Correlation of NTRK genetic fusions with mismatch repair protein deletion in patients with colorectal cancer / 中华病理学杂志

Objective: To investigate the relationship between the expression of four mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2) and NTRK genetic fusions in colorectal cancer. Methods: The paraffin-embedded tissue blocks of 830 cases of colorectal cancer were collected at the Affiliated Drum Tower Hospital, Nanjing University Medical School, China, from 2015 to 2019. Immunohistochemical and fluorescence in situ hybridization(FISH) method were used respectively to detect the expression of mismatch repair proteins and the break-apart of NTRKs; and the relationship between the expression of mismatch repair proteins and the NTRK genetic fusions was analyzed. Results: The overall mismatch repair protein deficiency (dMMR) rate was 9.88% (82/830), the mismatch repair proteins proficiency (pMMR) rate was 90.12%(748/830). The total deficiency rate of MLH1 protein was 9.04% (75/830), hPMS2 protein deficiency rate was 9.04% (75/830), MSH2 protein deficiency rate was 2.53% (21/830), MSH6 protein deficiency rate was 4.10% (34/830), the deficiency rate of synchronous MLH1 and PMS2 were 8.67% (72/830) and the deficiency rate of synchronous MSH2 and MSH6 were 2.17% (18/830). The dMMR group was associated with tumor location, different histological subgroups, tumor differentiation, AJCC stage and N stage (P<0.05). There were six cases (7.32%) carrying NTRK fusion by FISH among the 82 cases of dMMR, but only seven cases (0.94%) carrying NTRK fusion among the 748 cases of PMMR. The NTRKs translocation by FISH in all 13 cases were further confirmed by next generation sequencing. Among the clinicopathological characteristics, only differentiation showed significant difference between NTRK fusion positive and negative groups (P<0.05). More importantly, NTRK fusion was enriched in dMMR group (7.32% vs. 0.94%). Conclusion: In dMMR colorectal cancer group, the prevalence of NTRK fusion is higher than that in pMMR group.

Association of status of mismatch repair protein expression and EB virus infection with clinicopathological parameters in 886 gastric adenocarcinoma patients / 中华胃肠外科杂志

Objective: To analyze the expression of mismatch repair (MMR) protein and the EB virus infection in gastric adenocarcinoma, and to examine the association of MMR expression and EB virus infection with clinicopathological parameters. Methods: A case-control study was performed. Clinicopathological data of patients who was pathologically diagnosed as gastric adenocarcinoma, received radical gastrectomy and had complete clinicopathological data from August 2017 to April 2020 in Tianjin Medical University Cancer Institute and Hospital were retrospectively collected and analyzed. The immunohistochemistry (IHC) of MMR proteins and in situ hybridization (ISH) of Epstein-Barr virus encoded RNA (EBER) were reviewed. The associations of MMR and EBER results with clinicopathological parameters were analyzed. The main observations of the study were MMR and EBER expression, and association of MMR and EBER results with clinicopathological parameters. Results: Eight hundred and eighty-six patients were enrolled, including 98 patients who received preoperative neoadjuvant chemoradiotherapy. Of 886 patients, 613 (69.2%) were males and the median age was 60 (22-83) years; 831 (93.8%) were mismatch repair proficiency (pMMR), and 55 (6.2%) were mismatch repair deficiency (dMMR). In dMMR group, 47 cases (85.5%) had the deficiency of both MLH1 and PMS2, 1 case (1.8%) had the deficiency of both MSH2 and MSH6, 4 cases (7.3%) had the deficiency only in PMS2, 2 cases (3.6%) had the deficiency only in MSH6, and 1 case (1.8%) had the deficiency only in MSH2. The deficiency rates of PMS2, MLH1, MSH6 and MSH2 were 5.8% (51/886), 5.3% (47/886), 0.3% (3/886) and 0.2% (2/886), respectively. Among the 871 cases with EBER results, 4.9% (43/871) were positive EBER. Univariate analysis showed that dMMR was more frequently detected in female patients (χ(2)=10.962, P=0.001), cancer locating in the antrum (χ(2)=9.336,P=0.020), Lauren intestinal type (χ(2)=9.718, P=0.018), stage T3 (χ(2)=25.866, P<0.001) and TNM stage II (χ(2)=15.470, P=0.002). The ratio of dMMR was not significantly associated with age, tumor differentiation, histological type, lymph node metastasis, distant metastasis or Her-2 immunohistochemical score (all P>0.05). Compared with negative EBER, positive EBER was more frequent in male patients (χ(2)=9.701, P=0.002), cancer locating in gastric fundus and corpus (χ(2)=17.964, P<0.001), gastric cancer with lymphoid stroma (χ(2)=744.073, P<0.001) and poorly differentiated cancer (χ(2)=13.739, P=0.010). Positive EBER was not significantly associated with age, depth of invasion, lymph node metastasis, distant metastasis, TNM stage or Her-2 immunohistochemical score (all P>0.05). In addition, all dMMR cases were EBER negative, and all cases of positive EBER were pMMR. Conclusions: The positive EB virus status is mutually exclusive with dMMR, indicating that different molecular subtypes of gastric adenocarcinoma are involved in different molecular pathways in tumorigenesis and progression. The overlapping of dMMR or positive EBER status and positive Her-2 expression is found in some cases of gastric adenocarcinoma. Patients with gastric adenocarcinoma after radical surgery should be tested for MMR status if they are female, the tumor locates in gastric antrum, the TNM staging is stage II or T3, or if the Lauren classification is intestinal type. And if patients are male, the tumor locates in the gastric fundus and corpus, the cancer is lymphoid stroma, or poor differentiated, the expression of EBER should be detected. Results of our study may provide evidence for further decision-making of clinical treatment.

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.

Immunoexpression of TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers and its correlation with degree of differentiation, tumor staging and prognostic factors in colorectal adenocarcinoma: a retrospective longitudinal study

ABSTRACT BACKGROUND: There are cases of colorectal tumors that, although small, show more aggressive evolution than large tumors. This motivated us to study whether there are any proteins capable of alerting about these changes. The aim here was to correlate the immunoexpression of the TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers in tumors in patients with colorectal adenocarcinoma, with the degree of cell differentiation, tumor staging and clinical-pathological prognostic factors. DESIGN AND SETTING: Retrospective observational study at a public tertiary-level hospital. METHODS: We analyzed tissue-microarray paraffin blocks of tumor tissues that had been resected from 107 patients. We used Fisher's exact test to study associations between tumor differentiation/staging and the immunoexpression of biomarkers. We also used Kaplan-Meier estimation, the log-rank test and the adjusted Cox regression model to investigate the patients' overall survival (in months) according to biomarkers and disease-free interval. RESULTS: The degree of tumor differentiation and tumor staging were not associated with the biomarkers, except in cases of patients in stages III or IV, in which there was a correlation with MLH1 expression (P=0.021). Patient survival and disease-free interval were not associated with the biomarkers. CONCLUSION: There were no associations between the degree of tumor differentiation, staging, length of survival or disease-free interval and the immunoexpression of the TS, p53, COX2, EGFR or MSH6 tumor markers. In advanced cases of colorectal adenocarcinoma (stages III and IV), there was a higher percentage of MLH1-negative results.

Relevance of hMLH1 -93G>A, 655A>G and 1151T>A polymorphisms with colorectal cancer susceptibility: a meta-analysis based on 38 case-control studies

SUMMARY OBJECTIVE: There has been increasing interest in the study of the association between human mutL homolog 1 (hMLH1) gene polymorphisms and risk of colorectal cancer (CRC). However, results from previous studies are inconclusive. Thus, a meta-analysis was conducted to derive a more precise estimation of the effects of this gene. METHODS: A comprehensive search was conducted in the PubMed, EMBASE, Chinese Biomedical Literature databases until January 1, 2018. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association. RESULTS: Finally, 38 case-control studies in 32 publications were identified met our inclusion criteria. There were 14 studies with 20668 cases and 19533 controls on hMLH1 −93G>A, 11 studies with 5,786 cases and 8,867 controls on 655A>G and 5 studies with 1409 cases and 1637 controls on 1151T>A polymorphism. The combined results showed that 655A>G and 1151T>A polymorphisms were significantly associated with CRC risk, whereas −93G>A polymorphism was not significantly associated with CRC risk. As for ethnicity, −93G>A and 655A>G polymorphisms were associated with increased risk of CRC among Asians, but not among Caucasians. More interestingly, subgroup analysis indicated that 655A>G might raise CRC risk in PCR-RFLP and HB subgroups. CONCLUSION: Inconsistent with previous meta-analyses, this meta-analysis shows that the hMLH1 655A>G and 1151T>A polymorphisms might be risk factors for CRC. Moreover, the −93G>A polymorphism is associated with the susceptibility of CRC in Asian population.

RESUMO OBJETIVO: Tem havido crescente interesse no estudo da associação entre polimorfismos do gene mutL homólogo 1 humano (hMLH1) e risco de câncer colorretal (CRC). No entanto, os resultados de estudos anteriores não são conclusivos. Assim, uma meta-análise foi conduzida para obter uma estimativa mais precisa dos efeitos desse gene. MÉTODOS: Uma pesquisa abrangente foi realizada nas bases de dados PubMed, Embase, Chinese Biomedical Literature até 10 de janeiro de 2018. Odds ratio (OR) com 95% de intervalo de confiança (IC) foi utilizado para avaliar a força da associação. RESULTADOS: Finalmente, foram identificados 38 estudos de casos e controles em 32 publicações, atendendo aos nossos critérios de inclusão. Houve 14 estudos com 20.668 casos e 19.533 controles em hMLH1 −93G>A, 11 estudos com 5.786 casos e 8.867 controles em 655A>G e cinco estudos com 1.409 casos e 1.637 controles em 1151T>Um polimorfismo. Os resultados combinados mostraram que os polimorfismos 655A>G e 1151T>A estavam significativamente associados ao risco de CRC, enquanto que o polimorfismo −93G>A não estava significativamente associado ao risco de CRC. Quanto à etnia, os polimorfismos de −93G>A e 655A>G foram associados ao risco aumentado de CRC entre os asiáticos, mas não entre os caucasianos. Mais interessante, a análise de subgrupos indicou que 655A>G pode aumentar o risco de CRC em subgrupos PCR-RFLP e HB. CONCLUSÃO: Inconsistente com a meta-análise anterior, esta meta-análise mostra que os polimorfismos hMLH1 655A>G e 1151T>A podem ser fatores de risco para CRC. Além disso, o polimorfismo −93G>A está associado à susceptibilidade do CRC na população asiática.

Link between immunoexpression of hMLH1 and hMSH2 proteins and clinical-epidemiological aspects of actinic cheilitis

Abstract: Background: The studies found in the literature associate the immunoexpression of hMLH1 and hMSH2 proteins with histologic aspects, but do not correlate it with clinical and epidemiological data. Objective: To evaluate the immunoexpression of hMLH1 and hMSH2 in actinic cheilitis, correlating it with clinical characteristics. Methods: We analyzed 40 cases. Histological and immunohistochemical analyses were performed. The following clinical variables were evaluated: gender, age range, ethnicity, clinical aspect and occupational sunlight exposure. Statistical evaluation included the Student t-test, while the significance level was set at 5%. Results: Greater immunoexpression of hMLH1 and hMSH2 was observed in females, individuals aged over 40, and mixed-race/black patients. Furthermore, the immunoexpression of these proteins was greater in actinic cheilitis with a white-colored appearance and in patients without occupational sunlight exposure. No statistical differences were observed for the variables studied. Conclusion: This study uncovered variations of hMLH1 and hMSH2 protein expression upon evaluation of clinical aspects in actinic cheilitis.

Mutación fundadora en síndrome de Lynch tipo II / Founder mutation in Lynch syndrome

El síndrome de Lynch es la más frecuente de las neoplasias colorrectales hereditarias. Se origina por mutaciones germinales deletéreas familia-específicas en los genes que codifican proteínas de reparación del ADN: MLH1 (homólogo humano de mutL), MSH2 y MSH6 (homólogo humano de mutS 2 y 6, respectivamente), PMS2 (homólogo humano de PMS1 2) y MUTYH (homólogo humano de la ADN-glycosilasa mutY). La mutación c.2252_2253delAA, p.Lys751Serfs*3 en el exón 19 del gen MLH1 segrega con un haplotipo descripto en la región norte de Italia y cuyo origen fue atribuido a un efecto fundador. Esta mutación co-segrega con características típicas del síndrome de Lynch, incluyendo afectación temprana y múltiples tumores primarios en el mismo individuo, una alta frecuencia de cáncer pancreático, elevada inestabilidad microsatelital y falta de expresión de PMS2. En el presente trabajo se comunica dicha mutación en una paciente argentina con adenocarcinoma endometroide de útero en cuya historia familiar existen antecedentes de cáncer de colon diagnosticado antes de los 50 años en familiares de primer grado, reuniendo los criterios de Ámsterdam I y síndrome de Lynch II. Los polimorfismos presentes en la paciente coinciden con el haplotipo descripto en una región del norte de Italia. El alto grado de patogenicidad asociada a esta mutación hace imprescindible el estudio de todos los integrantes de las familias con cáncer hereditario permitiendo el diagnóstico genético pre-sintomático, la instauración de tratamientos o conductas preventivas y su seguimiento.

Lynch syndrome is the most frequent syndrome in hereditary colorectal cancer, a family-specific deleterious mutations in genes encoding DNA reparation proteins: MLH1 (mutL homolog 1), MSH2, MSH6 (mutS homolog 2 y 6, respectively), PMS2 (PMS1 homolog 2, mismatch repair system component) y MUTYH (mutY DNA glycosylase).The c.2252_2253delAA, p.Lys751Serfs*3 mutation in MLH1 gene segregates with a haplotype reported in the northern region of Italy and whose origin was attributed to a founder effect. This mutation co-segregates with typical characteristics of Lynch syndrome, including early age at onset and multiple primary tumors in the same individual, a high frequency of pancreatic cancer, high microsatellite instability and lack of PMS2 expression. This report describes a mutation in an Argentinian patient with endometrioid adenocarcinoma of uterus. Her first-degree relatives had a history of colon cancer diagnosed before 50 years, fulfilling the Amsterdam Criteria I and Lynch syndrome II. The high pathogenicity associated to this mutation makes necessary the study of all members from families with hereditary cancer, allowing pre-symptomatic genetic diagnosis, early assessment and the instauration of preventive treatments.

Expression difference of DNA mismatch repair gene hMLH1 and hMSH2 between schistosomiasis-associated colorectal cancer and sporadic colorectal cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To investigate the expression difference of DNA mismatch repair gene hMLH1 and hMSH2 between schistosomiasis-associated colorectal cancer and sporadic colorectal cancer.</p><p><b>METHOD</b>Clinical and pathological data of colorectal cancer patients receiving operations in Zhejiang Cancer Hospital between January 2008 and December 2010 were retrospectively analyzed. Patients were divided into schistosomiasis group(n=80) and sporadic group (n=258) according to the preoperative history and pathologic results. Pathological specimens were collected and tissue chips were made to analyze the expression of hMLH1 and hMSH2 by immunohistochemistr.</p><p><b>RESULTS</b>Compared with sporadic group, older age [(62.2 ± 9.6) year vs. (57.2 ± 11.7) year, P=0.000)], lower platelet level [(197.0 ± 59.6) × 10(9)/L vs. (217.0 ± 84.3) × 10(9)/L, P=0.02] and lower WBC level [(5.9 ± 1.9) × 10(9)/L vs. (6.6 ± 2.8) × 10(9)/L, P=0.02] were found in schistosomiasis group. Ratio of low differentiation-undifferentiation tumor was significantly higher in schistosomiasis group [44.2% (34/77) vs. 4.9% (12/247), P<0.05]. Lower positive rate of hMLH1 expression [77.5% (62/80) vs. 98.1% (253/258), P=0.000] and hMSH2 expression [75.0% (60/80) vs. 95.3% (246/258), P=0.000] was found in schistosomiasis group compared with sporadic group. Concurrent schistosomiasis was one of the risk factors of hMLH1/hMSH2 deficiency (RR: 0.913, 95% CI: 0.836-0.997, P=0.043), but not an independent factor (RR: 0.951, 95% CI: 0.867-1.043, P=0.286).</p><p><b>CONCLUSION</b>Schistosomiasis is associated with lower positive expression of hMLH1 and hMSH2, which indicates that hMLH1/hMSH2 deficiency may be a potential mechanism of schistosomiasis inducing carcinogenesis of colorectal cancer.</p>

Effect of methylation of hMLH1 gene promotor on stage tumorigenesis and progression of human gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To illustrate the role of methylation level of hMLH1 gene promoter in different stages of gastric carcinogenesis by methylation-specific PCR (MSP) detection of samples from paracancerous tissue and gastric cancer tissue.</p><p><b>METHODS</b>Methylation status of hMLH1 gene promoter of 40 patients undergoing radical stomach cancer operation in the Tumor Research Institute of China Medical University between January 2006 and August 2006 was detected by MSP. For each patient, 2 samples were chosen from the cancer site, paracancerous tissues of 1 cm, 3 cm, 5 cm away from the cancer site, separately. One sample was used in pathology examination, and the other in methylation detection.</p><p><b>RESULTS</b>Positive rates of hMLH1 gene promoter methylation in the paracancerous tissues of 1 cm, 3 cm, 5 cm away from the cancer site were 10%(4/40), 12.5%(5/40) and 2.5%(1/40) respectively, which were significantly lower than 32.5%(13/40) in cancer site(all P<0.05). Pathological examination showed precancerous lesions in 23 samples of paracancerous 1 cm and 3 cm tissues and normal tissues in 24 samples of paracancerous 5 cm tissues. Positive rates of hMLH1 gene promoter methylation in the cancer site, paracancerous tissue and normal gastric tissue were 32.5%(13/40), 8.7%(2/23) and 0(0/24) (P<0.01). For cancer tissue penetrated the gastric serosa, 8 out of 14 tissue samples were positive methylation (57.1%), which was significantly higher compared with 5 out of 26 tissue samples without penetration of gastric serosa(19.2%). Positive rate of hMLH1 gene promoter methylation in tissue samples with 7 or more of metastatic lymphatic node number was 61.5%(8/13), which was higher compared to that with less than 7(5/27, 18.5%) (P<0.05). No significant differences of positive rate of hMLH1 gene promoter methylation were found between different tumor gross types, tumor grow pattern, tumor differentiation degree, patient age and sex(all P>0.05).</p><p><b>CONCLUSION</b>Hypermethylation of hMLH1 gene promoter may be associated with the carcinogenesis stages and progression of human gastric cancer.</p>

Analysis of the relationship of DNA mismatch repair with clinicopathologic features and prognosis of colon cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the relationship between DNA mismatch repair (MMR) and clinicopathologic features and prognosis in patients with stages II and III colon cancers.</p><p><b>METHODS</b>The clinical and pathological data of 440 patients with stage II/III colon cancer after radical resection were retrospectively reviewed and analyzed. Immunohistochemical staining was used to assess the expression of MMR proteins (MLH1, MSH2, MSH6 and PMS2), and the correlation between DNA MMR and clinicopathological features and prognosis of colon cancers was analyzed.</p><p><b>RESULTS</b>Of the 440 tumor samples tested for DNA mismatch repair status, 90 (20.5%) demonstrated defective DNA mismatch repair and 350 (79.5%) had proficient DNA mismatch repair. Defective DNA mismatch repair (dMMR) was associated with young patients (≤ 60), proximal colon cancer, stage II, poorly differentiated adenocarcinoma and mucinous adenocarcinoma (P<0.05 for all). Among the 440 patients, 126 (28.6%) cases had recurrence or metastasis and 93 (21.1%) died during the median follow-up of 61.0 months. The five-year disease-free survival (DFS) rate was 82.2% among the patients with tumor exhibiting dMMR, significantly higher than that in patients with tumors exhibiting pMMR (68.9%, P=0.02). The univariate and mutlivariate analyses showed that the MMR status is an independent factor affecting 5-year disease-free survival and overall survival (OS) in colon cancer patients (P<0.05 for both).</p><p><b>CONCLUSIONS</b>Defective DNA mismatch repair (dMMR) is associated with patients with proximal colon cancer, stage II and poorly defferentiated adenocarcinoma and mucinous adenocarcinoma. The prognosis for patients with dMMR is better than those with pMMR. dMMR may be a useful biomarker for the prognosis of colon cancer.</p>

Genomics of Hereditary Colorectal Cancer: Lessons Learnt from 25 Years of the Singapore Polyposis Registry

<p><b>INTRODUCTION</b>The Singapore Polyposis Registry (SPR) was established in 1989 in Singapore General Hospital (SGH). The aims were to provide a central registry service to facilitate identification, surveillance and management of families and individuals at high risk of colorectal cancer.</p><p><b>MATERIALS AND METHODS</b>This is a review of published literature in the department.</p><p><b>RESULTS</b>The registry currently has 253 families with several genetic conditions-93 familial adenomatous polyposis (FAP) families, 138 Amsterdam-criteria positive presumed Lynch syndrome (LS) families, 12 families with Peutz Jeghers syndrome, 2 families with Cowden's syndrome, and 8 families with hereditary mixed polyposis syndrome (HMPS). There are also 169 families with a strong family history of colorectal cancer but no abnormal genes yet identified. In FAP, a diagnostic tool developed has allowed a 94% local APC germline detection rate in FAP families. Knowledge obtained studying the phenotype of FAP patients has allowed better choice of surgery between ileal pouch anal anastomosis (IPAA) against an ileal-rectal anastomosis (IRA). In LS, our review has noted a highly heterogenous mutational spectrum and novel variants made up 46.7% (28/60) of all variants identified in this cohort. This may suggest that our Southeast Asian ethnic groups have distinct mutational variants from Western populations. Pathogenic mutations were only confined to MLH1 and MSH2, and identified in 28.8% of families.</p><p><b>CONCLUSION</b>The impact of predictive gene testing for hereditary cancer risk in clinical practice has allowed evolution of care. Risk-reducing surgery and aggressive surveillance allows reduction in morbidity and mortality of patients. The SPR will continue to grow and improve outcomes in hereditary colorectal cancer patients and families.</p>

Screening for Lynch syndrome in colorectal cancer / 中华病理学杂志

<p><b>OBJECTIVE</b>To evaluate the application of mismatch repair (MMR) genes proteins expression to screen for Lynch syndrome in colorectal cancer patients.</p><p><b>METHODS</b>One hundred consecutive colorectal cancers cases collected from 2012 to 2013 were tested immunohistochemically for the protein expression of MLH1, MSH2, MSH6 and PMS2, and also by the ARMS method for the mutation status of BRAF genes in those cases lacking protein expression for MLH1.</p><p><b>RESULTS</b>The result of MMR immunocytochemistry showed that nine of 100 cases lacked MMR protein expression, including three cases each that were MLH1-/PMS2- and MSH2-/MSH6- respectively, two cases were MLH6- and one case was PMS2-; overall, the majority of these cases lacked protein expression of MLH1 and MSH2. The BRAF genes mutation test showed one case of mutation, indicating that the patient might have MLH1 gene methylation as a result of the mutation of BRAF genes, and that was a sporadic case. The age of onset for patients lacking MMR protein expression was lower than patients with sporadic colorectal cancer (P = 0.011). Colorectal cancers associated with the lack of MMR protein expression mostly occurred in the right colon (P = 0.001), and histomorphologically were often accompanied by mucinous adenocarcinoma (P = 0.010) and tumor lymphocytic infiltration.</p><p><b>CONCLUSION</b>Immunohistochemical staining for MMR proteins in patients with colorectal cancer, accompanied by testing for BRAF genes mutation, may be an effective approach to screen for Lynch syndrome.</p>

Immunophenotypes and gene mutations in colorectal precancerous lesions and adenocarcinoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To analyze immunophenotypes and gene mutations of colorectal precancerous lesions and adenocarcinoma, and to compare the difference of carcinogenetic mechanisms between the two precancerous lesions.</p><p><b>METHODS</b>Fifty-three cases of colorectal serrated lesions including 30 hyperplastic polyps, 20 sessile serrated adenomas (SSA) and 3 mixed polyps were collected from January 2006 to June 2012.Forty-five cases of traditional adenomas and 50 cases of colorectal adenocarcinomas were also recruited. Thirty hyperplastic polyps, 20 cases of SSA, 3 mixed polyps and 45 traditional adenomas were investigated by immunohistochemistry for the expression of DNA mismatch repair (MMR) proteins (MLH1, MSH2 and MSH6) and DNA methyltransferase MGMT. Mutations of KRAS, BRAF and PIK3CA genes in 10 cases of SSAs, 10 traditional adenomas, 1 mixed polyps and 50 colorectal adenocarcinomas were analyzed by PCR followed by direct Sanger sequencing.</p><p><b>RESULTS</b>(1) Only 3 cases of hyperplastic polyps lost MLH1 expression, and none of SSAs or traditional adenomas showed loss of MLH1. The negative expression rates of MSH2, MSH6 and MGMT in hyperplastic polyps and SSA were significantly higher than those of traditional adenomas. (2) KRAS mutation was found in 5/10 cases of SSAs, 5/10 traditional adenomas and 1/1 mixed polyps. (3) Colorectal adenocarcinomas harbored the mutations of KRAS (48%, 24/50), BRAF (6%, 3/50) and PIK3CA (4%, 2/50).</p><p><b>CONCLUSIONS</b>Immunophenotypic and gene mutation profiles are different between colorectal serrated lesion and traditional adenoma. Alterations of MMR and MGMT expression play important roles in the pathogenesis of "serrated neoplasm". KRAS mutation is a significant genetic change in the early phase of colorectal carcinogenesis.</p>

Aberrant methylation of hMLH1 gene promoter in papillary thyroid cancer and its clinical significance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the aberrant promoter methylation of hMLH1 gene promoter and its clinical significance in papillary thyroid cancer (PTC).</p><p><b>METHODS</b>methylation of hMLH1 gene promoter in the cancer tissue and matched tumor-adjacent normal tissue of 152 PTC patients were detected by real-time methylation specific PCR (qMSP). The relationship between the methylation of hMLH1 gene promoter and clinicopathological features was analyzed.</p><p><b>RESULTS</b>The methylation rate of hMLH1 gene promoter in cancer tissues was 37.5% (57/152), of which 33 cases were totally methylated and 24 cases were partially methylated. The methylation rate of adjacent normal tissues was 5.3% (8/152)(all were partially methylated). The methylation rate of PTC tissues was significantly higher than that in the tumor-adjacent normal tissue (P < 0.01). The promoter methylation of hMLH1 gene in PTC was significantly correlated with age, size and number of the primary lesion, local invasion, T stage and lymph node metastasis (P < 0.05) , but not correlated with gender and clinical stage (P > 0.05).</p><p><b>CONCLUSION</b>Promoter methylation of hMLH1 gene is a common molecular event in PTC tissue, and it is significantly correlated with the progression of PTC.</p>

hMLH1 gene promoter methylation in joint cartilage in patients with osteoarthritis / 中南大学学报(医学版)

OBJECTIVE@#To investigate the role of Human MutL homologue 1 (hMLH1) gene promoter methylation in the occurrence and development of osteoarthritis (OA).@*METHODS@#General DNA was dealt with sodium bisulfite. The methylation of hMLH1 promoter was detected by methylation-specific PCR (MSP). hMLH1 protein expression in joint cartilage was detected by immunohistochemical method.@*RESULTS@#The positive percent of hMLH1 promoter methylation in OA patients was higher than that in healthy persons (χ(2)=30.634, P<0.001); the positive percent of hMLH1 protein in OA patients was significantly lower than that in healthy persons (χ(2)=37.724, P<0.001); prmoter methylation and protein expression level of hMLH1 gene showed negative correlation (rs=-0.554, P<0.001).@*CONCLUSION@#hMLH1 promoter is hypermethlated in joint cartilage cells of OA patients. Hypermethylation may affect the protein expression of hMLH1, which might play a role in the occurrence and development of OA.

Effects of Baicalin on an orthotopic transplantation mouse model of mismatch repair gene deficient colorectal cancer / 中华外科杂志

<p><b>OBJECTIVE</b>To study the anticancer effects of Baicalin on an orthotopic transplantation mouse model of mismatch repair gene deficient colorectal cancer.</p><p><b>METHODS</b>Sixty orthotopic transplantation mice model of human colon cancer cell line HCT-116 expressing eGFP were established, which were divided randomly into negative controlled group (5% NaHCO3) and 50, 100, 200 mg/kg Baicalin groups. The nude mice were treated with intragastric infusion twice a day. Nude mice growth state, average weigh, inhibition rate of transplanted tumor, tumor metastasis and survival state were observed.</p><p><b>RESULTS</b>At 14, 21 and 28 days after treatment with different dose of Baicalin, tumor growth velocity was significantly slower in the treatment groups, and tumor volume was significantly smaller than the controlled group (there were (832 ± 637), (2012 ± 1566) and (2494 ± 1557) mm(3) respectively in 14, 21 and 28 days) (F = 4.433, P < 0.05). At the end point of study, survival state of 100 mg/kg group (13/15) was superior to controlled group (8/15) and 200 mg/kg group (8/15) (χ(2) = 4.665 and 3.980, P < 0.05).However, there were no significant differences in tumor metastasis and tumor surface vessel density.</p><p><b>CONCLUSIONS</b>Baicalin has statistically significant effects in inhibiting tumor growth in an orthotopic transplantation mouse model of mismatch repair gene deficient colorectal cancer, and 100 mg/kg may be an ideal treatment dose.</p>

Expression of hMLH1 in rectal intraepithelial neoplasm and early rectal carcinoma / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore whether the abnormality of hMLH1 gene may be an early event of carcinogenesis in rectal carcinoma, and to evaluate the diagnostic value in differentiation between intraepithelial neoplasm and early stage of colorectal carcinoma.</p><p><b>METHODS</b>The expression of hMLH1 protein in 28 cases with early invasive rectal carcinoma(EIRC), 36 cases with rectal intraepithelial neoplasm(RIEN), and 30 cases with normal rectal mucosa(NRM) which were collected through surgical operations were detected by PV-9000 immunohistochemical method.</p><p><b>RESULTS</b>The positive expression rates of hMLH1 protein were 100%(30/30), 77.8%(28/36), and 39.3%(11/28) in NRM, RIEN, and EIRC respectively. The difference was statistically significant between RIEN and EIRC(P=0.002), and the difference was also statistically significant between RIEN and NRM(P=0.006). The positive expression of hMLH1 was not related to age, gender, tumor maximum diameter, dysplasia, tumor types, and distance from the anal verge in RIEV group(P>0.05). In EIRC group, hMLH1 was associated with tumor differentiation(P<0.05).</p><p><b>CONCLUSION</b>hMLH1 gene deletion may be an early event during carcinogenesis of rectal carcinoma, which may be useful in differentiation of intraepithelial neoplasm from early rectal carcinoma.</p>

Expression of MMR in endometrial adenocarcinoma in women under 50 years old / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6 and PMS2) in endometrial adenocarcinoma (EC) of patients under 50 years and to explore the relationship between MMR expression and clinicopathological features including body mass index (BMI), histological grade and pathological stage of EC.</p><p><b>METHODS</b>MMR gene expression was investigated by immunohistochemical S-P method in endometrial adenocarcinomas of patients under age of 50. The control groups included complexity atypical hyperplasia endometrium (CAHE), simple hyperplasia endometrium (SHE), normal endometrium (NE) of patients under age of 50 and EC of patients older than 65 years.</p><p><b>RESULTS</b>Twenty seven of 40 EC (67.5%) lost at least one MMR protein expression. Loss of at least one MMR protein expression was seen in 5/15 cases of CAHE, 1/13 SHE and 1/11 NE, respectively (P < 0.01). The rates of loss of expression of MLH1, MSH2, MSH and PMS2 proteins in EC were 52.5%, 12.5%, 35.0%, and 30.0%, respectively. The difference between MLH1 and MSH6 expression among the four groups were significant (P < 0.05), but the expression of MSH2 showed no significant difference among the groups (P = 0.295). The expression of MMR protein had no relationship with histological grade and pathological stage, although loss of MSH6 was more frequently seen in patients of higher BMI.</p><p><b>CONCLUSIONS</b>Abnormal expression of MMR proteins is correlated with the development of EC from complex atypical hyperplasia. With the exception of the correlation of MSH6 expression with higher BMI, the expression of MMR proteins in EC has no significant relationship with histological grade and pathological stage.</p>

Reversal effect of 5-Aza-dc on cisplatin-resistance in human NSCLC cells in vitro / 中华肿瘤杂志

<p><b>OBJECTIVE</b>The aim of this study was to investigate the effect of 5-aza-2'-deoxycytidine (5-Aza-dc), a methylation inhibitor, on cisplatin-resistance in non-small cell lung cancer cell line A549/DDP and to explore its possible mechanism.</p><p><b>METHODS</b>MTT assay was used to test the cytotoxicity of 5-Aza-dc on A549/DDP cells, and the IC(50) and cisplatin resistance index of A540/DDP cells at 48 hours after 5-Aza-dc (0 µmol/L, 20 µmol/L, 40 µmol/L) treatment at different concentrations. MSP, fluorescence quantitative RT-PCR (real-time RT-PCR) and Western blot were used to detect the hMLH1 methylation status, mRNA and protein expressions, respectively.</p><p><b>RESULTS</b>The IC(50) value of cisplatin in A549/DDP cells was 30.15 ± 0.76 µmol/L. The MTT assay results demonstrated that during the 5-Aza-dc treatment for 48 hours, the dose of 20 µmol/L was non-toxic and 40 µmol/L was low-toxic. 5-Aza-dc at those two doses reduced IC(50) value of cisplatin to 16.54 ± 0.35 µmol/L (RI = 1.82) and 6.82 ± 0.16 µmol/L (RI = 4.42), respectively. MSP, real-time RT-PCR and Western blot showed that 5-Aza-dc at non-toxic and low-toxic doses removed the partial hMLH1-hypermethylation, and up-regulated hMLH1 mRNA and protein expressions.</p><p><b>CONCLUSIONS</b>Low dose 5-Aza-dc can partially reverse the cisplatin-resistance in A549/DDP cells, which may be achieved through removal of hMLH1 hypermethylation and increased expression of hMLH1 gene. 5-Aza-dc may have a role in increasing the efficacy of chemotherapy for patients whose tumors are lack of hMLH1 expression because of hMLH1 promoter hypermethylation.</p>

Methylation of p16 and hMLH1 genes in esophageal squamous cell carcinoma and reflux esophagitis / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the promoter methylation pattern of p16 and hMLH1 genes in esophageal squamous cell carcinoma and reflux esophagitis, and to correlate the results with clinical and pathologic findings.</p><p><b>METHODS</b>Twelve cases of normal esophagus, 13 cases of esophageal squamous cell carcinoma, 43 cases of reflux esophagitis with basal cell hyperplasia and 21 cases of reflux esophagitis with dysplasia, as confirmed by endoscopic and pathologic examination, were enrolled into the study. Genomic DNA was extracted. The promoter methylation status of p16 was measured by methylation-specific polymerase chain reaction. The promoter methylation status of hMLH1 was measured by sodium bisulfite-restriction enzyme digestion. Immunohistochemical study for p16 and hMLH1 proteins was also carried out.</p><p><b>RESULTS</b>The rates of p16 methylation in normal esophageal epithelium, basal cell hyperplasia, dysplasia and esophageal squamous cell carcinoma were 0/12, 14.0% (6/43), 38.1% (8/21) and 6/13, respectively. The p16 methylation correlated with the progress of esophageal lesions. On the other hand, the hMLH1 methylation was not observed in the normal esophageal epithelium and reflux esophagitis. One case of esophageal squamous cell carcinoma showed the presence of hMLH1 methylation. The hMLH1 promoter hypermethylation did not correlate with the clinical and pathologic features.</p><p><b>CONCLUSIONS</b>The p16 methylation may be one of the earliest events in the pathogenesis of esophageal squamous cell carcinoma and is also observed in reflux esophagitis. Reflux esophagitis may be related to the development of esophageal squamous cell carcinoma in Chinese population. In contrast, hMLH1 methylation may not be directly involved in the tumorigenesis of esophageal squamous cell carcinoma.</p>