Diagnostic methods for peritoneal molecular residual disease in gastric cancer / 中华胃肠外科杂志

Peritoneal metastasis of gastric cancer serving as the most frequent form of metastasis, is one of the leading causes of death. A portion of surgically treated patients often suffer from small peritoneal residual metastasis, which will lead to recurrence and metastasis of gastric cancer patients after surgery. Given these, the prevention and treatment of peritoneal metastasis of gastric cancer deserves more attention. Molecular residual disease (MRD) refers to the molecular abnormalities of tumor origin that cannot be found by traditional imaging or other laboratory methods after treatment, but can be found by liquid biopsy, representing the possibility of tumor persistence or clinical progress. In recent years, the detection of MRD based on ctDNA has gradually become a research hotspot in the prevention and treatment of peritoneal metastasis. Our team established a new method for MRD molecular diagnosis of gastric cancer, and reviewed the research achievements in this field.

Genomics of next generation sequencing in pediatric B-acute lymphoblastic leukemia and its impact on minimal residual disease / 中华儿科杂志

Objective: To describe the gene mutation profile of newly diagnosed pediatric B-acute lymphoblastic leukemia (B-ALL) and analyze its effect on minimal residual disease (MRD). Methods: A total of 506 newly diagnosed B-ALL children treated in Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences from September 2018 to July 2021 were enrolled in this retrospective cohort study. The enrolled children were divided into MRD ≥1.00% group and <1.00% group according to MRD results on the 19th day since chemotherapy, and MRD ≥0.01% group and <0.01% group according to MRD results on the 46th day. Clinical characteristics and gene mutations of two groups were compared. Comparisons between groups were performed with chi-square test or Fisher's exact test. Independent risk factors of MRD results on the 19th day and the 46th day were analyzed by Logistic regression model. Results: Among all 506 patients, there were 318 males and 188 females. On the 19th day, there were 114 patients in the MRD ≥1.00% group and 392 patients in the MRD <1.00% group. On the 46th day, there were 76 patients in the MRD ≥0.01% group and 430 patients in the MRD <0.01% group. A total of 187 gene mutations were detected in 487 (96.2%) of 506 children. The most common gene mutations were signal transduction-related KRAS gene mutations in 111 cases (22.8%) and NRAS gene mutations in 99 cases (20.3%). Multivariate analysis showed that PTPN11 (OR=1.92, 95%CI 1.00-3.63), KMT2A (OR=3.51, 95%CI 1.07-11.50) gene mutations and TEL-AML1 (OR=0.48, 95%CI 0.27-0.87), BCR-ABL1 (OR=0.27, 95%CI 0.08-0.92) fusion genes and age >10 years (OR=1.91, 95%CI 1.12-3.24) were independent influencing factors for MRD ≥1.00% on the 19th day. BCORL1 (OR=2.96, 95%CI 1.18-7.44), JAK2 (OR=2.99, 95%CI 1.07-8.42) and JAK3 (OR=4.83, 95%CI 1.50-15.60) gene mutations and TEL-AML1 (OR=0.43, 95%CI 0.21-0.87) fusion gene were independent influencing factors for MRD ≥0.01% on the 46th day. Conclusions: Children with B-ALL are prone to genetic mutations, with abnormalities in the RAS signaling pathway being the most common. Signal transduction related PTPN11, JAK2 and JAK3 gene mutations, epigenetic related KMT2A gene mutation and transcription factor related BCORL1 gene mutation are independent risk factors for MRD.

Research Progress of Next Generation Sequencing in Acute Leukemia --Review / 中国实验血液学杂志

With the advent of precision medicine, next-generation sequencing (NGS) is playing an increasingly important role in clinical oncology diagnosis and treatment with its advantages of high sensitivity, high accuracy, high efficiency and operability. NGS reveals the genetic characteristics of acute leukemia(AL) patients by screening for specific disease-causing genes to identify occult as well as complex genetic mutations in patients with AL, leading to early diagnosis and targeted drug therapy for AL patients, as well as to predict disease recurrence by detecting mnimal residual disease (MRD) and analyzing mutated genes to determine patient prognosis. NGS plays an increasingly important role in the diagnosis, treatment and prognosis assessment in AL, providing a direction for the pursuit of precision medicine. This paper reviews the research progress of NGS in AL.

Enfermedad residual medible mediante reordenamientos de inmunoglobulinas y receptores de linfocitos-T / Measurable residual disease by rearrangements of immunoglobulins and T-lymphocyte receptors

Resumen Las leucemias agudas constituyen la neoplasia más frecuente en pacientes pediátricos. Actualmente, el 80% de los niños con leucemia linfoblástica aguda (LLA) logran curarse con quimioterapia con vencional pero el 20% de los mismos presentarán una reaparición de la enfermedad. La enfermedad residual medible (ERM) ha sido descripta como un importante factor pronóstico, que permite evaluar la respuesta de los pacientes al tratamiento. Una de las técnicas más sensibles par a estudiar ERM es la cuantificación de reordena mientos génicos de inmunoglobulinas (Ig) y receptores de linfocitos-T (TCR). Los objetivos del presente trabajo fueron describir los reordenamientos detectados de Ig/TCR, evaluar el efecto de la ERM en la supervivencia de niños con LLA y comparar la ERM por Ig/TCR con la cuantificada mediante citometría de flujo multiparamétrica (CFM). Del total de 455 pacientes estudiados, en el 96% fue posible caracterizar al menos un reordenamiento de Ig/TCR. El total de reordenamientos clonales detectados fue de 1550. La ERM pudo ser estudiada en forma exitosa en el 89% de los casos. El valor de ERM positiva combinada al día 33 y 78 de tratamiento, permitió identificar pacientes de alto riesgo, entre los previamente estratificados por la ERM mediante CFM al día 15. La comparación entre la determinación de ERM mediante reordenamientos Ig/TCR y CFM mostró una excelente correlación. El presente trabajo constituye un estudio de ERM mediante Ig/TCR realizado en un número muy significativo de pacientes diagnosticados en forma consecutiva, tratados en el marco de un protocolo homogéneo y con excelente seguimiento clínico.

Abstract Acute leukemias are the most common neoplasm in pediatric patients. Currently, 80% of children with diagnosis of acute lymphoblastic leukemia (ALL) are cured with conventional chemotherapy, but 20% of them will have a recurrence of the disease. Measurable Residual Disease (MRD) has been described as an important prognostic factor that allows evaluating the response of patients to treatment. One of the most sensitive techniques to study MRD is the quantification of immunoglobulins (Ig) and T-lymphocyte receptors (TCR) genes rearrangements. The aims of this study were to describe the detected Ig/TCR rearrangements, to evaluate the prognostic impact of MRD in our population of children with ALL and to compare the MRD values by Ig/TCR with those obtained by multiparametric flow cytometry (MFC). A total of 455 patients were studied. In 96% of the cases, it was possible to characterize at least one Ig/TCR rearrangement. The total number of Ig/TCR rear rangements detected was 1550. MRD was successfully applied in 89% of the cases. The combined positive MRD values at day 33 and 78 of treatment allow the identification of high-risk patients in cases previously stratified by MRD using flow cytometry at day 15. The comparison between MRD determination by Ig/TCR rearrangements and FC showed excellent correlation. The present work constitutes a study of MRD by Ig/TCR carried out in a very significant number of patients consecutively diagnosed, treated within a homogeneous protocol and with excellent clinical follow-up.

Clinical significance of minimal residual disease in B-lineage acute lymphoblastic leukemia pediatric patients with different fusion gene backgrounds / 中国当代儿科杂志

OBJECTIVE@#To study the clinical significance of minimal residual disease (MRD) in B-lineage acute lymphoblastic leukemia (B-ALL) pediatric patients with different fusion gene backgrounds.@*METHODS@#A retrospective analysis was performed on the medical data of 441 B-ALL children who were treated from January 2008 to April 2015. Among the 441 children, 336 had negative fusion gene, 79 had positive @*RESULTS@#In patients with negative fusion gene, the positive MRD group had significantly lower overall survival (OS) rate and event-free survival (EFS) rate (@*CONCLUSIONS@#MRD has the most definite prognostic significance in pediatric B-ALL patients with negative fusion gene, while it has unsatisfactory prognostic significance in those with positive

Leucemia linfoblástica aguda infantil: una aproximación genómica / Acute lymphoblastic leukemia: a genomic perspective

Resumen: En paralelo al proyecto de la secuenciación del genoma humano, se han desarrollado varias plataformas tecnológicas que están permitiendo ganar conocimiento sobre la estructura del genoma de las entidades humanas, así como evaluar su utilidad en el abordaje clínico del paciente. En la leucemia linfoblástica aguda (LLA), el cáncer infantil más común, las herramientas genómicas prometen ser útiles para detectar a los pacientes con alto riesgo de recaída, ya sea al diagnóstico o durante el tratamiento (enfermedad mínima residual), además de que permiten identificar los casos en riesgo de presentar reacciones adversas a los tratamientos antineoplásicos y ofrecer una medicina personalizada con esquemas terapéuticos diseñados a la medida del paciente. Un ejemplo claro de esto último es la identificación de polimorfismos de un solo nucleótido (SNPs) en el gen de la tiopurina metil transferasa (TPMT), donde la presencia de dos alelos nulos (homocigotos o heterocigotos compuestos) indica la necesidad de reducir la dosis de la mercaptopurina hasta en un 90% para evitar efectos tóxicos que pueden conducir a la muerte del paciente. En esta revisión se proporciona una visión global de la genómica de la LLA, describiendo algunas estrategias que contribuyen a la identificación de biomarcadores con potencial utilidad en la práctica clínica.

Abstract: In parallel to the human genome sequencing project, several technological platforms have been developed that let us gain insight into the genome structure of human entities, as well as evaluate their usefulness in the clinical approach of the patient. Thus, in acute lymphoblastic leukemia (ALL), the most common pediatric malignancy, genomic tools promise to be useful to detect patients at high risk of relapse, either at diagnosis or during treatment (minimal residual disease), and they also increase the possibility to identify cases at risk of adverse reactions to chemotherapy. Therefore, the physician could offer patient-tailored therapeutic schemes. A clear example of the useful genomic tools is the identification of single nucleotide polymorphisms (SNPs) in the thiopurine methyl transferase (TPMT) gene, where the presence of two null alleles (homozygous or compound heterozygous) indicates the need to reduce the dose of mercaptopurine by up to 90% to avoid toxic effects which could lead to the death of the patient. In this review, we provide an overview of the genomic perspective of ALL, describing some strategies that contribute to the identification of biomarkers with potential clinical application.

Role of RT-PCR and FISH in diagnosis and monitoring of acute promyelocytic leukemia.

Background: Patients with a presence of Promyelocytic Leukemia-Retinoic Acid Receptor Alpha (PML-RARA) genes rearrangement predict a favorable response to all-trans retinoic acid (ATRA), and a significant improvement in survival. Therefore, establishing the presence of PML-RARA rearrangement is important for optimal patient management. Aim: The objective of this study is to compare and assess the role of fluorescent in situ hybridization (FISH) and reverse transcriptase polymerase chain reaction (RT-PCR) in the diagnosis and long-term monitoring of Acute Promyelocytic Leukemia (APL). Materials and Methods: We compared 145 samples received at different interval of times to analyze the sensitivity of RT-PCR and FISH. Results: The failure rate for RT-PCR was 4% at baseline, 13% at induction, and 0% at the end of consolidation. And for FISH it was 8% at baseline, 38% at induction, and 66% at the end of consolidation. The predictive values of relapse in the patients who were positive and negative by RT-PCR, at the end of induction, were 60 % and 3%, respectively, and at end of consolidation it was 67 % and 4%, respectively. On the other hand the predictive values of relapse in patients who were positive and negative by FISH at end of induction were 57 % and 6%, respectively; while at end of consolidation it was 14% who were negative by FISH. Conclusion: Both RT-PCR and FISH are important for the diagnosis of APL cases, as both techniques complement each other in the absence or failure of any one of them. However, RT-PCR is more sensitive than FISH for the detection of minimal residual disease in the long-term monitoring of these patients. The present study shows that the predictive value of relapse is more associated with minimal residual disease (MRD) results by RT-PCR than that by FISH.

Use of immunoglobulin heavy chain and kappa light chain gene rearrangements by PCR for molecular diagnosis of minimal residual disease in Iranian children suffering from beta-precursor acute lymphoblastic leukemia

Diversity of IgH and IgK molecules is generated during B and T Lymphocyte differentiation through the rearrangement of variable, diversity, junction and constant gene segments. Additionally, random insertion and deletions of nucleotides between gene segments make unique sequences which are cell or clone specific. Similar IgH and IgK genes rearranged in normal cells of lymphoid leukemia cases can be used as a marker of clonality and for evaluation of minimal residual disease [MRD]. The purpose of this study is to evaluate the pattern of IgH chain and IgK gene rearrangements using polymerase chain reaction [PCR] in beta-precursor acute lymphoblastic leukemias [ALL] to follow the MRD at day 14, day 28 [end of remission induction], week 10, 3-6 months and 6-12. month after the initiation of treatment. In our prospective study bone marrow aspirates of 183 children at the mean age of 63.6 months with diagnosis of acute leukemia were collected at admission before any chemotherapy. After reviewing cytomorphology and immunophenotyping, only 140 cases with diagnosis of beta-precursor ALLs were selected for study. Mononuclear cells including leukemic blasts were isolated by density gradient. After DNA extraction, IgH and IgK [V[K] I-IV / Kde] were amplified by consensus primers using PCR. PCR products were analyzed after heteroduplex analysis and polyacrylamide gel electrophoresis [silver stain]. The DNA sequences were compared and aligned with the sequences homologous for IgH and IgK published by Gene Bank. The follow up specimens were collected at day 14, day 28 [end of remission induction], day 45-month 3, and 3-6 months and 6-12 months after initiation of treatment. After routine cytomorphologic analysis, similar PCR was done on follow up extracted DNAs in parallel with diagnosis DNA. MRD was considered to be approved positive if bands similar to those at the time of diagnosis were present. Statistical analysis using SPSS software [version 11.5] was performed. 90.5% of patients had clonal IgH gene rearrangements. Monoclonal, biclonal and oligoclonal patterns were observed in 57.8%, 34.9% and 5.5% of patients with IgH [CDR III] rearrangement, respectively. Clonal patterns of IgK-Kde were detected in 59 [67%; n: 88] of BP-ALLs. According to cytomorphology about 92% of patients were in complete remission. MRD positivity decreased from more than 90% to 20% using different gene rearrangements in defined time points. Four patients who relapsed during follow up were MRD positive using 1-3 rearrangements and all except one were in clinical remission. Clonal rearrangement of IgH had a pattern similar to other populations. IgK was slightly more frequent than previously reported and the VKI [25%] was the most common type. These differences can be explained by different techniques, DNAs and clonality markers. According to the results, these clonal markers can be used in diagnosis and follow up of MRD

Evaluation of bi/oligoclonal rearrangement of immunoglobulin and T-cell receptor genes in Iranian children suffering B-precursor acute lymphoblastic leukemia

Clonal gene rearrangement of immunoglobulin and T cell receptor may have mono, bi or oligoclonal pattern. Significance of these patterns were studied at diagnosis and follow up of MRD in many countries, however, similar studies have not been conducted among Iranian patients. We investigated the bi/oligoclonal pattern and their association with quantitative and qualitative parameters especially MRD in Iranian children suffering from B-precursor acute lymphoblastic leukemia. In our prospective study, bone marrow aspirates of 140 patients with B-precursor ALLs were selected. Mononuclear cells including leukemic blasts isolated by density gradient. Having DNA extracted, hypervariable regions of IgH, IgK, TCR-delta [D delta 2-D delta 3, V delta 2-D delta 3] and TCR-lambda [V lambda, V lambda I, V lambda II] were amplified by consensus primers using PCR. PCR products were analyzed after heteroduplex analysis and polyacrylamide gel electrophoresis [silver stain]. The DNA sequences were compared and aligned to the sequences homologous for IgH and IgK published by Gene Bank. Bone marrow aspirates of days 14, 28 and 45, as well as months 3 and 6 were treated similarly. IgH gene rearrangements were reported in 114 [90.5%] patients using consensus primers for CDR-III and CDR-I regions [monoclonal: 57.8%, biclonal:34.9% and oligoclonal:5.5%]. Clonal pattern of IgK-Kde were present in 59 cases [67%] [biclonal:10%] Clonal rearrangement of TCR-lambda [V lambda] and V lambda I/II were present in 79.3% and 64.9% of patients, respectively, however, only 5% of cases showed biclonal pattern. The V lambda II rearrangement was the most common [46.8%] type in TCR-lambda. 47 [45.2%] and 11 [16.6%] patients had V delta 2-D delta 3 and D delta 2-D delta 3 partial gene rearrangements, respectively. Biclonal/oligoclonal pattern were present in 13 [27.7%] and 2 [4.3%] cases with V delta 2-D delta 3 rearrangement. Only one patient had biclonal D delta 2-D delta 3 rearrangement. No significant difference regarding the quantitative and qualitative parameters and MRD was observed between the two groups. Bi/oligoclonal rearrangement of IgH, IgK, TCR-delta [D delta 2-D delta 3, V delta 2-Ddelta 3] and TCR-lambda [V lambda, V lambda I, Vlambda II] genes had comparable pattern to other populations. Results of MRD study showed no significant differences between the two groups

Fluorescent in-situ hybridization (FISH) for BCR/ABL in chronic myeloid leukemia after bone marrow transplantation

CONTEXT: Identification of Philadelphia chromosome or BCR/ABL gene rearrangement in chronic myeloid leukemia is important at diagnosis as well as after treatment. OBJECTIVE: To compare the results of karyotyping using fluorescent in-situ hybridization (FISH) upon diagnosis and 1 year after bone marrow transplantation in 12 patients. TYPE OF STUDY: Diagnostic test and residual disease detection. SETTING: Hematology and Hemotherapy Department, Federal University of São Paulo/Escola Paulista de Medicina, São Paulo, Brazil. SAMPLE: 12 patients with chronic myeloid leukemia at diagnosis and 1 year after bone marrow transplantation. DIAGNOSTIC TEST: Karyotyping was done in the usual way and the BCR/ABL gene-specific probe was used for FISH. MAIN MEASUREMENTS: Disease at diagnosis and residual. RESULTS: At diagnosis, 10 patients presented t(9;22)(q34.1;q11) as well as positive FISH. Two cases did not have metaphases but FISH was positive. After bone marrow transplantation, 8 patients presented normal karyotype, 1 had persistence of identifiable Philadelphia chromosome and 3 had no metaphases. Two cases showed complete chimera and 2 had donor and host cells simultaneously. FISH was possible in all cases after bone marrow transplantation and confirmed the persistence of identifiable Philadelphia chromosome clone in one patient, and identified another that did not present metaphases for analysis. Cases that showed mixed chimera in karyotype were negative for BCR/ABL by FISH. CONCLUSION: The applicability of FISH is clear, particularly for residual disease detection. Classical and molecular cytogenetics are complementary methods