A robust microsatellite instability detection model for unpaired colorectal cancer tissue samples / 中华医学杂志(英文版)

BACKGROUND@#Microsatellite instability (MSI) is a key biomarker for cancer immunotherapy and prognosis. Integration of MSI testing into a next-generation-sequencing (NGS) panel could save tissue sample, reduce turn-around time and cost, and provide MSI status and comprehensive genomic profiling in single test. We aimed to develop an MSI calling model to detect MSI status along with the NGS panel-based profiling test using tumor-only samples.@*METHODS@#From January 2019 to December 2020, a total of 174 colorectal cancer (CRC) patients were enrolled, including 31 MSI-high (MSI-H) and 143 microsatellite stability (MSS) cases. Among them, 56 paired tumor and normal samples (10 MSI-H and 46 MSS) were used for modeling, and another 118 tumor-only samples were used for validation. MSI polymerase chain reaction (MSI-PCR) was performed as the gold standard. A baseline was built for the selected microsatellite loci using the NGS data of 56 normal blood samples. An MSI detection model was constructed by analyzing the NGS data of tissue samples. The performance of the model was compared with the results of MSI-PCR.@*RESULTS@#We first intersected the target genomic regions of the NGS panels used in this study to select common microsatellite loci. A total of 42 loci including 23 mononucleotide repeat sites and 19 longer repeat sites were candidates for modeling. As mononucleotide repeat sites are more sensitive and specific for detecting MSI status than sites with longer length motif and the mononucleotide repeat sites performed even better than the total sites, a model containing 23 mononucleotide repeat sites was constructed and named Colorectal Cancer Microsatellite Instability test (CRC-MSI). The model achieved 100% sensitivity and 100% specificity when compared with MSI-PCR in both training and validation sets. Furthermore, the CRC-MSI model was robust with the tumor content as low as 6%. In addition, 8 out of 10 MSI-H samples showed alternations in the four mismatch repair genes ( MLH1 , MSH2 , MSH6 , and PMS2 ).@*CONCLUSION@#MSI status can be accurately determined along the targeted NGS panels using only tumor samples. The performance of mononucleotide repeat sites surpasses loci with longer repeat motif in MSI calling.

STIP1 correlates with tumor immune infiltration and prognosis as a potential immunotherapy target: a pan-cancer bioinformatics analysis / 南方医科大学学报

OBJECTIVE@#To investigate the correlation of stress-inducible phosphoprotein 1 (STIP1) expression level with prognosis of different cancers and its potential role in immunotherapy.@*METHODS@#TCGA, TARGET and GTEx databases were used for bioinformatic analysis of STIP1 expression level and its prognostic value in different cancers. We also detected STIP1 expression immunohistochemically in 10 pairs of colorectal cancer and adjacent tissues. We further analyzed the correlation of STIP1 expression level with tumor mutational burden, microsatellite instability, immune cell infiltration, immune regulators and outcomes of different cancers. STIP1- related proteins were identified using protein- protein interaction (PPI) network analysis, and functional enrichment analysis was performed to analyze the regulatory pathways involving STIP1.@*RESULTS@#Bioinformatics analysis showed that STIP1 was highly expressed in most tumors compared with the normal tissues (P < 0.05), which was confirmed by immunohistochemistry of the 10 pairs of colorectal cancer tissues. STIP1 expression level was correlated with clinical stages of multiple cancers (P < 0.05), and in some cancer types, an upregulated STIP1 expression was correlated with a poor prognosis of the patients in terms of overall survival, disease-specific survival, disease-free survival and progression-free survival (P < 0.05). STIP1 expression was significantly correlated with tumor mutational burden, microsatellite instability, immune cell infiltration and immunomodulatory factors in most tumors (P < 0.05). PPI network analysis indicated that STIP1-related proteins included HSPA4, HSPA8, and HSP90AA1. KEGG enrichment analysis suggested that the high expression of STIP1 in liver cancer was related mainly with valerate metabolism, tryptophan metabolism, and butyrate metabolism pathways; HALLMARK enrichment analysis suggested high STIP1 expression in liver cancer was involved in bile acid and fatty acid metabolism.@*CONCLUSION@#STIP1 is up-regulated in multiple cancer types and its expression level is correlated with clinical tumor stage, tumor mutational burden, microsatellite instability, immune cell infiltration and immunomodulatory factors.

Analysis of microsatellite instability in endometrial cancer: The significance of minimal microsatellite shift / 北京大学学报(医学版)

OBJECTIVE@#To analyze the differences and characteristics of microsatellite instability (MSI) in endometrial cancer (EMC), by using colorectal cancer (CRC) as control.@*METHODS@#In the study, 228 cases of EMC were collected. For comparative analysis, 770 cases of CRC were collected. Mismatch repair (MMR) expression was detected by immunohistochemistry (IHC), and microsatellite instability (MSI) was analyzed by PCR and capillary electrophoresis fragment analysis (MSI-PCR). MSI-PCR was detected using five mononucleotide repeat markers: BAT-25, BAT-26, NR-21, NR-24, and MONO-27.@*RESULTS@#In EMC, we found 27.19% (62/228) of deficient mismatch repair (dMMR) using IHC, significantly higher than CRC (7.79%, 60/770). Meanwhile, subclonal expression of MMR protein was found in 4 cases of dMMR-EMC and 2 cases of dMMR-CRC. According to the criteria of major micro-satellite shift, we found 16.23% (37/228) of MSI-high (MSI-H), 2.63% (6/228) of MSI-low (MSI-L), and 81.14% (185/228) of microsatellite stability (MSS) in EMC using MSI-PCR. The discor-dance rate between MMR-IHC and MSI-PCR in EMC was 11.84% (27/228). In CRC, we found 8.05% (62/770) of MSI-H, 0.13% (1/770) of MSI-L, and 91.82% (707/770) of MSS. The discordance rate between MMR-IHC and MSI-PCR in CRC was only 0.52% (4/770). However, according to the criteria of minimal microsatellite shift, 12 cases of EMC showed minimal microsatellite shift including 8 cases of dMMR/MSS and 4 cases of dMMR/MSI-L and these cases were ultimately evaluated as dMMR/MSI-H. Then, 21.49% (49/228) of EMC showed MSI-H and the discordance rate MMR-IHC and MSI-PCR in EMC decreased to 6.58% (15/228). No minimal microsatellite shift was found in CRC. Compared with EMC group with major microsatellite shift, cases with minimal microsatellite shift showed younger age, better tumor differentiation, and earlier International Federation of Gynecology and Obstetrics (FIGO) stage. There were significant differences in histological variant and FIGO stage between the two groups (P < 0.001, P=0.006).@*CONCLUSION@#EMC was more prone to minimal microsatellite shift, which should not be ignored in the interpretation of MSI-PCR results. The combined detection of MMR-IHC and MSI-PCR is the most sensitive and specific method to capture MSI tumors.

Comparative study of next generation sequencing and immunohistochemistry on molecular classification of endometrial carcinoma / 中华病理学杂志

Objective: To investigate the differences in molecular classification of endometrial carcinoma (EC) between various technical methods and to explore molecular classification schemes suitable for Chinese population. Methods: The study used a comprehensive scheme of next generation sequencing (NGS) and immunohistochemistry for molecular classification of 254 EC cases that were obtained at Department of Pathology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China from April 2021 to March 2022. According to the recommended threshold of Sanger sequencing which was approximate-20% variant allele fraction (VAF), NGS data were extracted to simulate the results of Sanger sequencing. Results: The 254 EC patients had a mean age of 51 years (range, 24 to 89 years). Combination of POLE (9-14 exons), TP53 total exons and microsatellite instability (MSI) detection was a better single scheme than NGS alone, while combination of MSI fragment analysis and conventional immunohistochemistry was the best solution and seemed best aligned with TCGA data and recent studies. POLE ultramuted type, mismatch repair defect type, TP53 mutant type and non-specific molecular characteristic type accounted for 11.4% (29/254), 31.5% (80/254), 22.4% (57/254) and 34.6% (88/254) of the cases, respectively. If Sanger sequencing was adopted for POLE and TP53 detection, the frequencies of these EC types were 9.1% (23/254), 31.5% (80/254), 12.9% (33/254) and 46.6% (118/254), respectively, with greatly increasing non-specific molecular characteristics cases. If POLE was detected by Sanger sequencing and others by immunohistochemistry, they were 9.1% (23/254), 42.2% (92/218), 13.8% (35/254) and 40.9% (105/254), respectively, with increasing the false positive rates of the mismatch repair defect group. Conclusions: Small and medium-sized NGS panels with MSI detection is a better solution than NGS alone. Sanger sequencing is currently available for POLE mutation detection, which is not sensitive enough for TP53 mutation detection, and seems equivalent to the efficiency of TP53 by immunohistochemistry. Further optimization of small and medium-sized NGS panels covering MSI detection and POLE and TP53 full exons may be the best choice for the future to meet national conditions.

Neoadjuvant immunotherapy for colorectal cancer / 中华胃肠外科杂志

Immunotherapy has been one of the hot topics in the field of colorectal cancer research in recent years. Patients with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) are the main beneficiaries of immunotherapy. The response rate of patients with dMMR/MSI-H colorectal cancer receiving neoadjuvant immunotherapy is nearly 100%, of which the pathological complete response rate approximately accounts for 60%-67%. The prospect of neoadjuvant immunotherapy in dMMR or MSI-H colorectal cancer patients, especially in the rectal cancer patients, lies in achieving sustainable clinical complete response so as to achieve organ preservation and avoid adverse effects on reproductive, sexual, bowel and bladder function after surgery and radiotherapy. Studies have shown that part of the colorectal cancer patients of microsatellite stability (MSS) or mismatch repair proficient (pMMR) can respond to neoadjuvant immunotherapy in combination with other treatment methods such as radiotherapy and chemotherapy. In pMMR or MSS colorectal cancer, optimizing neoadjuvant immunotherapy regimens and finding effective efficacy prediction biomarkers are important research directions. In neoadjuvant immunotherapy, overcoming primary and secondary resistance and identifying the pseudoprogression and hyperprogression of neoadjuvant immunotherapy are clinical challenges that require attention. This paper comprehensively reviews the research progress, controversies,challenges and future research directions of neoadjuvant immunotherapy (mainly immune checkpoint inhibitors) in colorectal cancer.

Caracterización molecular de pacientes con cáncer colorrectal / Molecular characterization of colorectal cancer patients

Introducción. El cáncer colorrectal tiene una alta incidencia en la población mundial. Diversas vías moleculares están involucradas en su desarrollo, entre ellas, la inestabilidad cromosómica, la inestabilidad microsatelital y la epigenética. Objetivo. Hacer la caracterización molecular de 44 individuos con cáncer colorrectal esporádico. Materiales y métodos. El análisis de mutaciones en los genes APC, KRAS, TP53 y BRAF se hizo mediante secuenciación de Sanger; la inestabilidad microsatelital se determinó mediante electroforesis capilar utilizando cinco marcadores de repetición corta en tándem (Short Tandem Repeat) y el estado de metilación del promotor del gen MLH1 se hizo con la técnica MS-PCR (Methylation-Specific PCR). Resultados. La frecuencia de mutación de los genes APC, KRAS y TP53 fue del 18,1, 25 y 4,5 %, respectivamente; las mutaciones detectadas se localizaron con mayor frecuencia en el colon derecho. La frecuencia de inestabilidad microsatelital fue del 27,2 % y el 73,1 % en los tumores con metilación en el gen MHL1, y el 91,6 % de los tumores con inestabilidad microsatelital presentaba metilación en el gen MLH1. En el grupo de tumores con estabilidad microsatelital, las mutaciones en los genes APC, KRAS y TP53 fueron más frecuentes que en el grupo de tumores con inestabilidad microsatelital. La metilación del gen MLH1 fue la alteración más predominante. Conclusiones. En los pacientes con cáncer colorrectal evaluados se demostró la presencia de alteraciones moleculares en las diferentes vías genéticas, las cuales son comunes en su carcinogénesis. Los pacientes presentaron un perfil de mutaciones diferente al de otras poblaciones. Los hallazgos obtenidos en este estudio confirman la heterogeneidad molecular descrita en el desarrollo del cáncer colorrectal.

Introduction: Colorectal cancer has a high incidence in the world population. Different molecular pathways, such as chromosomal instability, microsatellite instability, and epigenetics are involved in its development. Objective: To perform molecular characterization in 44 individuals with sporadic colorectal cancer. Materials and methods: We conducted mutation analyses of the APC, KRAS, TP53 y BRAF genes using Sanger sequencing techniques; microsatellite instability was determined by capillary electrophoresis with five STR genetic markers while the methylation status of the MHL1 promotor gene was analyzed using methylation-specific PCR. Results: APC, KRAS, and TP53 genes mutation frequency was 18.1%, 25%, and 4.5%, respectively; the somatic mutations detected were located more frequently in the right colon. The frequency of microsatellite instability was 27.2% and 73.1% of the tumors had the MHL1 gene methylated while 91.6% of microsatellite instability-positive tumors had the methylated MLH1 gene. The mutation profile of microsatellite stability tumors APC, KRAS, and TP53 genes was more frequent than in the microsatellite instability-positive tumors. The methylation of the MLH1 gene was the most predominant molecular alteration. Conclusions: We identified molecular alterations in different genetic pathways of the colorectal cancer patients evaluated, which are common in the carcinogenesis of this cancer. These patients showed a different mutational profile compared to other populations. Our findings confirm the molecular heterogeneity described in the development of colorectal cancer.

Immunotherapy for microsatellite-instability-high advanced colorectal cancer / 中华胃肠外科杂志

Microsatellite instability-high (MSI-H) colorectal cancer accounts for approximately 10%-15% of all colorectal cancer patients, while in metastatic diseases the MSI-H population accounts for only 5% of patients. Previous studies have shown that early-stage MSI-H colorectal cancer patients have a good prognosis, but those with advanced disease have a poor prognosis and are not sensitive to chemotherapy. The advent of PD-1 antibodies has significantly improved the prognosis and changed treatment landscape in this population, not only achieving good outcomes in late-line therapy, but also significantly outperforming traditional chemotherapy combined with targeted therapy in first-line therapy. How to overcome primary and secondary drug resistance is a key issue in improving the outcome of MSI-H metastatic colorectal cancer, and commonly used approaches include changing chemotherapy regimens, combining with other immunotherapies, combining with anti-angiogenesis, and local treatments (surgery, radiotherapy, or interventional therapy). It is worth noting that immunotherapy has certain lifelong or even lethal toxicity, and the indications for neoadjuvant immunotherapy must be evaluated with caution. Neoadjuvant immunotherapy in MSI-H advantaged population can achieve high rates of pathological complete remission (pCR) and clinical complete remission (cCR). Therefore, for MSI-H patients with a strong intention to preserve anal sphincter and a strict evaluation of cCR after neoadjuvant immunotherapy, the Watch-and-Wait strategy offers an opportunity to preserve sphincter function and improve long-term survival quality in a subset of mid-to-low rectal cancers. Research on adjuvant immunotherapy in the field of colorectal cancer is also in full swing, and the results are worth waiting for.

m7G-lncRNAs are potential biomarkers for prognosis and tumor microenvironment in patients with colon cancer / 南方医科大学学报

OBJECTIVE@#To assess the value of m7G-lncRNAs in predicting the prognosis and microenvironment of colorectal cancer (CRC).@*METHODS@#We screened m7G-lncRNAs from TCGA to construct an m7G-lncRNAs risk model using multivariate Cox analysis, which was validated using ROC and C-index curves. Calibration and nomogram were used to predict the prognosis of CRC patients. Point-bar charts and K-M survival curves were used to assess the correlation of risk scores with the patients' clinical staging and prognosis. CIBERSORT and ESTIMATE were used to explore the association between the tumor microenvironment and immune cell infiltration in patients in high and low risk groups and the correlation of risk scores with microsatellite instability, stem cell index and immune checkpoint expression. A protein-protein interaction network was constructed, and the key targets regulated by m7G-lncRNAs were identified and validated in paired samples of CRC and adjacent tissues by immunoblotting.@*RESULTS@#We identified a total of 1722 m7G-lncRNAs from TCGA database, from which 12 lncRNAs were screened to construct the risk model. The AUCs of the risk model for predicting survival outcomes at 1, 3 and 5 years were 0.727, 0.747 and 0.794, respectively. The AUC of the nomogram for predicting prognosis was 0.794, and the predicted results were consistent with actual survival outcomes of the patients. The patients in the high-risk group showed more advanced tumor stages and a greater likelihood of high microsatellite instability than those in the low-risk group (P < 0.05). The tumor stemness index was negatively correlated with the risk score (r=-0.19; P=7.3e-05). Patients in the high-risk group had higher stromal cell scores (P=0.0028) and higher total scores (P=0.007) with lowered expressions of activated mast cells (r=-0.11; P=0.045) and resting CD4+ T cells (r=-0.14; P=0.01) and increased expressions of most immune checkpoints (P < 0.05). ATXN2 (P= 0.006) and G3BP1 (P=0.007) were identified as the key targets regulated by m7G-lncRNAs, and their expressions were both higher in CRC than in adjacent tissues.@*CONCLUSION@#The risk model based on 12 m7G-lncRNAs has important prognostic value for CRC and can reflect the microenvironment and the efficacy of immunotherapy in the patients.

Pan-cancer analysis of the expression pattern of long non-coding RNA MIR22HG / 南方医科大学学报

OBJECTIVE@#To conduct a pan-cancer analysis of the expression of long non-coding RNA (lncRNA) MIR22HG and explore its association with clinical characteristics.@*METHODS@#We analyzed the expression of MIR22HG in different tumors and its association with clinical staging, lymph node metastasis, tumor mutation burden (TMB) and microsatellite instability (MSI) using R package based on the Cancer Genome Atlas (TCGA) datasets. The relationship between MIR22HG expression and infiltrating immune cells was analyzed using TIMER algorithm. The association of MIR22HG gene alteration frequency with the clinical outcomes was examined using cBioPortal online software. Data form Genomics of Drug Sensitivity in Cancer (GDSC) were used to analyze the relationship between MIR22HG and the sensitivity of chemotherapy drugs. We specifically analyzed MIR22HG expression in hepatocellular carcinoma (HCC) and its correlation with sorafenib treatment using GEO database and verified the results in 12 pairs of HCC specimens. Kaplan-Meier analysis was performed to analyze the correlation of MIR22HG with the outcomes of sorafenib treatment. We also tested the effects of MIR22HG overexpression and knockdown on IC50 of sorafenib in HCC cells.@*RESULTS@#MIR22HG was downregulated in most tumors (P < 0.05), where its deletion mutations were frequent, and associated with a poor prognosis (P < 0.05). In many tumors, MIR22HG expression level was correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, immune checkpoint-related genes, and sensitivity to common chemotherapeutic drugs (P < 0.05). Among the 6 common infiltrating immune cells in cancers, neutrophil infiltration had the strongest correlation with MIR22HG expression level, especially in breast cancer, rectal cancer and kidney renal papillary cell carcinoma (P < 0.05). MIR22HG was downregulated in HCC in association with HCC progression (P < 0.05). In HCC patients, a low MIR22HG expression was associated with a favorable outcome after sorafenib treatment (HR=2.94, P=0.075) and was capable of predicting the response to sorafenib treatment (AUC=0.8095). Compared with the negative control, MIR22HG overexpression obviously reduced sorafenib sensitivity (with IC50 of 7.731 vs 15.61) while MIR22HG knockdown increased sorafenib sensitivity of HCC cells (with IC50 of 7.986 vs 5.085).@*CONCLUSION@#MIR22HG expression level is correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, and chemosensitivity in most cancer, suggesting its potential as an immunotherapeutic target and also a prognostic biomarker for tumors.

Presencia de inestabilidad microsatélite en pacientes colombianos con adenocarcinoma colorrectal / Microsatellite instability in Colombian patients with colorectal adenocarcinoma

Resumen Introducción y objetivos: la vía de inestabilidad de microsatélites (IMS) está implicada en la carcinogénesis de un 15 % de carcinomas colorrectales (CCR). La detección de esta alteración tiene relevancia en el pronóstico y en el tratamiento de los pacientes con CCR. El objetivo del presente estudio es determinar la prevalencia de IMS en CCR en una cohorte de pacientes de Bogotá, Colombia. Materiales y métodos: se evaluó por inmunohistoquímica la presencia de homólogo MutL 1 (MLH1), segregación posmeiótica aumentada 2 (PMS2), homólogo mutS 2 (MSH2) y homólogo mutS 6 (MSH6) en muestras de CCR prevenientes de colectomías. Adicionalmente, se analizaron las variables clinicopatológicas. A los casos con pérdida de MLH1 y PMS2 se les evaluó la mutación del gen BRAF. Resultados: en total se incluyeron 86 casos. La mediana de edad de los pacientes con CCR fue de 69 años, 52,3 % fueron hombres. De los pacientes con CCR, 12 (13,9 %) presentaron IMS, de los cuales 10 (83,3 %) tenían ausencia de expresión MLH1/PMS2 y 2 (16,7 %), de MSH2/MSH6. La mediana de edad de los pacientes con CCR e IMS fue de 52 años (45-76,5), 9 eran hombres y el 66,7 % de estos casos se localizaron en el colon derecho. El tipo histológico más frecuente fue adenocarcinoma moderadamente diferenciado (67 %). Los linfocitos infiltrantes al tumor fueron observados en el 83 %, la presencia de infiltrado de tipo Crohn estaba presente en el 42 %. La mutación de BRAF se observó en el 30 % de los pacientes con pérdida de MLH1 y PMS2. Conclusión: la prevalencia de la IMS en nuestra población fue de 14 %, datos similares a los observados en la población norteamericana y europea. Sin embargo, se observa que el 83 % presentó pérdida de expresión del complejo MLH1/PMS2, una prevalencia mayor comparada con otras poblaciones.

Abstract Introduction: The microsatellite instability (MSI) pathway is involved in the carcinogenesis of 15% of colorectal carcinomas (CRC). The detection of this alteration is relevant for the prognosis and treatment of CRC patients. Objective: The aim of this study is to determine the prevalence of MSI in CRC in a cohort of patients in Bogotá, Colombia. Materials and methods: The presence of MLH1, PMS2, MSH2, and MSH6 was evaluated by immunohistochemistry in CRC samples collected during colectomy. Clinicopathological variables were analyzed as well. Cases with loss of MLH1 and PMS2 were evaluated for BRAF gene mutation. Results: A total of 86 cases were included. The median age was 69 years, 52.3% were male. 12 (13.9%) patients had IMS, 10 (83.3%) had absence of MLH1/PMS2 expression and 2 (16.7%) absence of MSH2/MSH6 expression. The median age of patients with IMS was 52 years (45-76.5), of which 9 were male. 66.7% of carcinomas were located in the right colon and the most frequent histological type was moderately differentiated adenocarcinoma (67%). Tumor infiltrating lymphocytes were observed in 83% of the cases, while the presence of Crohn's-like infiltrate was present in 42%. BRAF mutation was observed in 30% of patients with loss of MLH1 and PMS2. Conclusion: The prevalence of IMS in our population was 14%, similar to the data observed in the North American and European populations. However, we observed that 83% had loss of expression of the MLH1/PMS2 complex, a higher prevalence compared to other populations.

The association between the histopathological features and microsatellite instability in young patients with urothelial carcinoma of the bladder

SUMMARY OBJECTIVE: Bladder cancer under the age of 40 is extremely rare. Bladder cancer development involves complex and multi-stage processes, one of which is the DNA damage repair mechanism. In this retrospective study, we aimed to evaluate the histopathological features of bladder urothelial carcinoma seen in patients under 40 years of age and tumor microsatellite instability status using immunohistochemistry. METHODS: A total of 50 patients under the age of 40 with urothelial bladder carcinoma from two different centers in the same country were included. Expression of the mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 was analyzed by immunohistochemistry. RESULTS: Age at the time of diagnosis ranged from 17 to 40 years old. Most tumors were non-invasive papillary urothelial carcinoma. Two cases had nuclear loss of MSH-6 and PMS-2. We observed that tumor grade, tumor stage, presence of tumor differentiation, and infiltrative growth pattern of the tumor have significant impact on prognosis, but microsatellite instability does not have an effective role in bladder carcinogenesis in young patients. CONCLUSIONS: Our results indicate that the presence of microsatellite instability is not related to the low tumor grade and stage in urothelial neoplasms in young patients, suggesting that urothelial carcinoma of the bladder in young patients may represent a genetically stable form of neoplasia.

Inestabilidad microsatelital y cáncer gástrico / Microsatellite instability and gastric cancer

La inestabilidad microsatelital es causada por una alteración de los sistemas de reparación de apareamiento incorrecto, que puede afectar los microsatélites dentro de todo el genoma humano, produciendo errores en su replicación. Los estudios publicados, principalmente en la literatura inglesa, han encontrado que algunos tumores, como los gástricos, pueden expresar inestabilidad microsatelital. En la siguiente revisión de tema, se presenta una descripción de los sistemas de reparación de apareamientos incorrectos y su relación con la presencia de inestabilidad microsatelital en los tumores gástricos, así como su posible utilidad clínica, como factor asociado en la respuesta al tratamiento con inmunoterapia en los pacientes con dicha patología

Microsatellite instability is caused by an alteration of the mismatch repair systems, which can affect microsatellites within the entire human genome, causing errors in their replication. Published studies, mainly in the English literature, have found that some tumors, such as gastric ones, can express microsatellite instability. In this review, a description of the mismatch repair systems and their relationship with the presence of microsatellite instability in gastric tumors is presented, as well as its possible clinical utility, as an associated factor in the response to immunotherapy treatment, in patients with gastric cancer

Genome instability and lymphoma / 中南大学学报(医学版)

Lymphoma is one of the most common malignant tumor of the hematologic system. The genome instability is not only an important molecular basis for the development of lymphoma, but also has important value in the diagnosis and prognosis of lymphoma. There are 2 types of genome instability: Microsatellite instability (MSI/MIN) at gene level and chromosomal instability at chromosome level. Through the study on genes associated with lymphoma, the unstable genes associated with lymphoma could be found, meanwhile the mechanism of its occurrence and development of lymphoma could be explored, and the important basis of molecular biology could also be provided in the field of current hot lymphoma precision medical research.

Advances in immunotherapy for neuroendocrine neoplasms / 中华胃肠外科杂志

Neuroendocrine neoplasms (NEN) is a rare and heterogeneous tumor. Different pathologic morphology, differentiation, grade and clinical stages of the tumors had various treatment and prognosis. Patients with recurrent or metastatic NEN have limited treatment options and poor prognosis. In recent years, PD-1 pathway blockade has become integral components of disease management for many cancers. Immunotherapy is being explored in NEN. Studies have shown that the efficacy of immune monotherapy in NEN is limited, and it can be considered for selected patients. Biomarkers for predicting efficacy of immunotherapy include PD-L1 expression, TMB-H, MSI-H/dMMR, etc. Combined regimens of anti-CTLA-4 and anti-PD-1/PD-L1 inhibitors, and immune checkpoint inhibitor combined with anti-angiogenic drugs or chemotherapy are promising in patients with NEN, and it is worthwhile to further explore of the responding populations.

Identificación del fenotipo de inestabilidad microsatelital en carcinoma colorrectal mediante el análisis de la expresión de proteínas reparadoras del ADN: Revisión narrativa / Identification of microsatellite instability phenotype in colorectal carcinoma through expression analysis of DNA mismatch repair proteins: Narrative review

El carcinoma colorrectal (CCR) es de las primeras causas de mortalidad del mundo, presentando Guatemala una incidencia anual de 7.4/millón de habitantes. El síndrome de Lynch se caracteriza clínicamente por un inicio temprano del CCR con lesiones causadas por alteraciones en genes que codifican proteínas reparadoras.Los microsatélites son regiones del ADN con una unidad repetitiva de uno o más nucleótidos y son susceptibles a errores durante la replicación de ADN de los enterocitos. Existe un sistema de reparación que corrige estos errores. Cuando las proteínas reparadoras de este sistema están mutadas o ausentes, dichos errores del ADN persisten. Estas proteínas reparadoras se expresan en el núcleo de las células colónicas normales y son detecta-bles utilizando estudios de inmunohistoquímica (IHQ). Los genes MLH1 y MSH2 pueden encontrarse mutados en el 90% de los casos de cáncer colorrectal y el resto corresponde a MSH6 y PMS2. Esta vía oncogénica se caracteriza por alteración del sistema de reparación de errores durante la replicación del ADN, controlado por los genes MMR (mismatch repair), principalmente MLH1, MSH2, MSH6 y PMS2. Se realizó una revisión extensa de la literatura en PubMed, Springer y JAMA, usando las palabras clave: fenotipo de CCR, Síndrome de Lynch e inestabilidad microsatelital, detectándose 55 artículos. El objetivo de esta revisión es describir la importancia de la identificación del fenotipo del CCR por medios de IHQ y de pruebas moleculares para el eficaz tratamiento con inmunoterapia anti-PD1/PD-L1.

Colorectal cancer (CRC) is one of the leading causes of mortality in the world. In Guatemala it's an important cause of morbidity (7.4 per million inhabitants). Lynch syndrome is clinically characterized by an early onset of nonpolyposis colorectal carcinoma, with multiple lesions and neoplasms. The syndrome is caused by mutations in genes encoding DNA mismatch repair proteins. The microsatellites are regions of the DNA that repeat between one or more nucleotides and are susceptible to errors during replication, these are corrected by a repair system, when genes are mutated, the errors persist. The genes encoding repair proteins are expressed in the nuclei of normal colonic cells which can be observed using immunohistochemical studies. The MLH1, MSH2 genes are found to be mutated in 90% of the cases and the rest corresponds to the MSH6 and PMS2 genes. This oncogenic pathway characteristically consists of an alteration in the DNA repair system that is controlled by mismatch repair genes (MMR). An extensive research was conducted on PubMed, Springer and JAMA, using the keyword: CRC phenotype, Lynch syndrome and microsatellite instability. 55 articles were found. This review«s objective is to understand the mechanisms of nonpolyposis colorectal cancer and the importance of identifying patients with a mutant phenotype as a predictive factor for the efficacy of the anti-PD1/PDL1 immunotherapy and for prognosis.

RNA-binding protein with serine-rich domain 1 regulates microsatellite instability of uterine corpus endometrial adenocarcinoma

OBJECTIVE: To determine the role of RNA-binding protein with serine-rich domain 1 (RNPS1) in uterine corpus endometrial carcinoma (UCEC), the role of RNPS1 knockdown in UCEC development in vitro and in vivo, and the relationship between RNPS1 and mismatch repair (MMR) in UCEC. METHODS: We predicted the potential function of RNPS1 using bioinformatics systems. The expression of RNPS1 in tissues and cell lines was analyzed by western blotting and immunohistochemistry. The expression of RNPS1 in MMR was assessed using bioinformatics and western blotting. The proliferation and apoptosis of UCEC cells were assessed under RNPS1 knockdown conditions, and RNPS1 regulation in MMR was detected by suppressing Notch signaling. Associations between RNPS1 and gene mutations in UCEC and prognosis were analyzed. RESULTS: The RNPS1 level was higher in UCEC tumors than in normal tissues and tumors or RL952 cells. Prognostic outcomes were worse when UCEC showed abundant RNPS1 expression. Lentiviral RNPS1 knockdown weakened tumor cell proliferation and suppressed biomarker expression, reduced the tumor volume, promoted apoptosis in vitro and in vivo, and inhibited UCEC development. Increased MutS homolog 2 (MSH2) and MutS homolog 6 (MSH6) levels in MMR after RNPS1 knockdown were reversed by inhibiting Notch signaling. Furthermore, RNPS1 was associated with mutations in NAA11, C2orf57, NUPR1, and other genes involved in UCEC prognosis. CONCLUSION: RNPS1 may regulate the expression levels of MSH2 and MSH6 in MMR, enhancing the proliferation, development, and prognosis of UCEC through a Notch signaling pathway in UCEC. Our study offers a new method and strategy for delaying UCEC development through modulating MMR.

PD-1 blockade as a future treatment for colorectal cancer with microsatellite instability / Bloqueio do PD-1 como futuro tratamento do cancro colorretal com instabilidade de microssatélites

ABSTRACT Introduction: Colorectal cancer is the third most common cancer worldwide, with about 15% of these tumours related with microsatellite instability, which confers distinct characteristics to these tumours, both clinicopathological and in the response to treatments. In fact, the poor response to chemotherapy in these tumours has led to the investigation for new treatments, with immunotherapy being the most successful one to date. The focus of this review is to assess the response of microsatellite unstable colorectal cancer to PD-1 blockade, and the mechanisms behind that response. Methods: A PubMed research was conducted, resulting in the inclusion of 47 articles in this review. Results: Microsatellite instability results in a high neoantigen load, leading to a highly active immune microenvironment of the tumour, mainly due to T-cells. To counteract this, there is an upregulation of PD-1, acting as a "brake" for immune cells, facilitating tumour growth and metastasis. This upregulation makes these tumours great candidates for treatment with PD-1 blockade, as seen in many clinical trials, where the overall responses and progression free survival rates were higher than those observed in microsatellite stable tumours. Conclusion: With the importance of colorectal cancer with microsatellite instability new treatments are necessary. Therefore, PD-1 blockade is a promising treatment for colorectal cancer with microsatellite instability, with improvement in survival rates and a better prognosis for these patients.

RESUMO Introdução: O câncer colorretal é o terceiro mais comum em todo o mundo, com cerca de 15% desses tumores relacionados com instabilidade dos microssatélites, o que confere características distintas a esses tumores, tanto clínico patológicas quanto na resposta aos tratamentos. De fato, a fraca resposta à quimioterapia nesses tumores levou à investigação de novos tratamentos, sendo a imunoterapia a mais bem sucedida até o momento. O foco desta revisão é avaliar a resposta do câncer colorretal com microssatélites instáveis ao bloqueio do PD-1 e os mecanismos por trás dessa resposta. Métodos: Foi realizada uma pesquisa na base de dados PubMed, resultando na inclusão de 47 artigos nesta revisão. Resultados: A instabilidade de microssatélites resulta em uma alta carga de neoantígenos, levando a um microambiente imunológico altamente ativo do tumor, principalmente devido às células T. Para neutralizar isso, há uma maior expressão do PD-1, atuando como um "freio" para as células imunes, facilitando o crescimento do tumor e suas metástases. Essa expressão faz desses tumores grandes candidatos ao tratamento com bloqueio PD-1, como demonstrado em vários ensaios clínicos, onde as respostas globais e as taxas de sobrevivência livres de progressão foram maiores do que as observadas em tumores com microssatélites estáveis. Conclusão: Com a importância do câncer colorretal com instabilidade de microssatélites, novos tratamentos são necessários. Portanto, o bloqueio do PD-1 é um tratamento promissor para o câncer colorretal com instabilidade de microssatélites, com melhora nas taxas de sobrevivência e melhor prognóstico para esses pacientes.

Prognosis in colorectal cancer beyond TNM / Prognóstico no carcinoma colorretal para além do TNM

ABSTRACT Introduction: Colorectal cancer is one of the neoplasms with the greatest social impact. Given the great molecular heterogeneity and diversity of pathophysiological mechanisms, it is difficult to define prognostic factors that could guide therapy. Objectives: To identify the molecular prognostic factors that may be of interest in clinical practice and to synthesize the existing evidence. Material and methods: The search for the articles was carried out using the PubMed platform and the keywords "sporadic colorectal cancer and prognosis", for articles published between 2014 and 2019. We selected all articles published on studies in humans and written in English or Portuguese. Of the 215 articles found, 35 articles were selected to perform this review. Results: Current evidence supports the use of four molecular markers in clinical practice − KRAS, NRAS and BRAF (EGFR signalling pathway) and the mismatch repair status. Conclusion: The use of molecular biomarkers in clinical practice to define prognosis is still little supported by the existent evidence. The studies are slightly contradictory, so new projects and international collaborations must be carried out in this area to obtain more robust evidence.

RESUMO Introdução: O carcinoma colorretal é uma das neoplasias com maior impacto social. Dada a grande heterogeneidade molecular e diversidade de mecanismos fisiopatológicos, torna-se difícil definir fatores de prognóstico que orientem a terapêutica. Objetivos: Identificar os fatores de prognóstico moleculares que poderão vir a ter interesse na prática clínica e fazer uma síntese da evidência existente. Material e métodos: A pesquisa dos artigos foi realizada recorrendo à plataforma PubMed e utilizou-se as palavras-chave "sporadic colorectal cancer and prognosis", para artigos publicados entre 2014 e 2019. Foram selecionados todos os artigos publicados sobre estudos em humanos e escritos em inglês ou em português. Dos 215 artigos encontrados, foram selecionados 35 artigos para realizar esta revisão. Resultados: A evidência atual apoia a utilização de quatro marcadores moleculares na prática clínica - KRAS, NRAS e BRAF (via de sinalização do EGFR) e o estado mismatch repair. Conclusão: A utilização na prática clínica de biomarcadores moleculares para definir o prognóstico é ainda pouco apoiada pela evidência disponível. Os estudos são algo contraditórios, pelo que novos projetos e colaborações internacionais devem ser realizados neste âmbito para se obter evidência mais robusta.

Clinicopathological features and types of microsatellite instability in 1394 patients with colorectal cancer / 南方医科大学学报

OBJECTIVE@#To explore the clinicopathological features and types of genic mutations in DNA mismatch repair (MMR) in colorectal cancer (CRC).@*METHODS@#Immunohistochemistry was used to determine the expression of MMR proteins in 1394 patients with CRC, and PCR-capillary electrophoresis (PCR-CE) was used to detect microsatellite instability (MSI) in 106 cases of defective MMR (dMMR), 46 cases of proficient MMR (pMMR) with heterogeneous expression and 147 randomly selected cases of pMMR. The relationship between the expressions of MMR proteins and the clinicopathological features of the patients was evaluated. The consistency between the results of immunohistochemistry and PCR-CE was assessed.@*RESULTS@#Immunohistochemical staining showed an incidence of dMMR of 7.6% in the patients. The main type of dMMR was co-deletion of MLH1 and PMS2, accounting for 55.7% of the total dMMR cases. The deletion of MMR proteins was significantly correlated with the patients' age, tumor location, tumor size, gross type, histological type, degree of differentiation, lymph node status and TNM stage (@*CONCLUSIONS@#The main type of dMMR is co-deletion of MLH1 and PMS2 in patients with colorectal cancer. dMMR colorectal cancer has typical clinicopathological features and a lower incidence in China than in Western countries. The results of immunohistochemistry and PCR-CE are highly consistent for detecting dMMR in colorectal cancer patients.

Características histopatológicas del carcinoma colorrectal con inestabilidad microsatelital (IMS) / Histopathologic characteristics of microsatellite instability in colorectal cancer

El carcinoma colorrectal es una de las neoplasias con mayor incidencia a nivel mundial. Algunos de los tipos tienen componente hereditario y asociación con defectos en la reparación génica a nivel replicacional, por mutaciones en los genes encargados (MLH1, MSH2, MSH6 y PMS2), llamándose esto la inestabilidad microsatelital. Esta situación se acompaña de mayor predisposición a desarrollar carcinoma colorrectal y algunos extracolónicos que incluyen cáncer de estómago, endometrio, ovarios y tracto urinario, entre otros. Es importante, entonces, evaluar la presencia de la inestabilidad microsatelital a nivel histopatológico conociendo que hay ciertos hallazgos que hacen sospechar la presencia de estas alteraciones genéticas, tales como la presencia de linfocitos intraepiteliales, infiltrado inflamatorio Crohn-like , el subtipo histológico y la localización. El objetivo de este artículo es revisar en detalle algunas características de las variables mencionadas, así como resaltar la importancia de otras variables histopatológicas con impacto pronóstico.

Colorectal cancer (CRC) is one of the most common cancers in the world. Some have a heritable component and are associated with a genetic defect in replication error repair due to MLH1, MSH2, MSH6 and PMS2 genes mutations known as microsatellite instability. This entails a greater predisposition to CRC and other extracolonic cancers including stomach, endometrium, ovary and urinary tract cancers, among other. Thus, it is important to detect histologic microsatellite instability through certain findings such as intraepithelial infiltrating lymphocytes, Crohn-like inflammatory reaction, histologic subtype and anatomical location leading to suspect the presence of genetic alterations. The objective of this article was to examine some features of said variables in detail and highlight the importance of other histopathologic variables with prognostic significance.