Frequency Of Genetic Aberrations Research Articles

Cytogenetic and molecular genetic diagnostics in oncohematological disorders: a position paper of the Organization of Molecular Geneticists in Oncology and Oncohematology

Introduction. Currently, there is no unequivocal opinion on the optimal list of studies for the genetic diagnosis of oncohematological disorders in children and adults. These discrepancies are due to the limited technological capabilities of laboratories, the rapid development of science, and a significant expansion of the range of new molecular markers, that are attractive, but only for a limited group of patients. Moreover, in modern conditions of limited access to resources, it seems important to bring desires, interests and opportunities to a common denominator. Aim — to develop unified approaches to the cytogenetic and molecular genetic diagnosis of oncohematological diseases in children and adults based on the consensus opinion of the panel of experts. Main findings. The review proposes the arrangement of cytogenetic and molecular genetic diagnostic tests in oncohematological disorders in children and adults into 3 categories depending on the frequency of genetic aberrations, the study complexity and the prognostic impact. Based on this and taking into account the diagnosis and age of patients, the minimal and optimal lists of clinically significant parameters and research markers were identified. The basic preanalytical principles for conducting cytogenetic and molecular genetic studies in oncohematology are pointed out. A brief description of a conventional cytogenetic study and a polymerase chain reaction for the diagnosis of oncohematological diseases is given. The paper also focused on the need for reference diagnostics of cytogenetic and molecular genetic studies in oncohematology. The article is addressed to the specialists in the field of laboratory genetics, clinical laboratory diagnostics, but may also be of interest to hematologists, pediatric oncologists and doctors of related branches.

TPX2 Amplification-Driven Aberrant Mitosis in Culture Adapted Human Embryonic Stem Cells with gain of 20q11.21.

Despite highly effective machinery for the maintenance of genome integrity in human embryonic stem cells (hESCs), the frequency of genetic aberrations during in-vitro culture has been a serious issue for future clinical applications. By passaging hESCs over a broad range of timepoints (up to 6years), the isogenic hESC lines with different passage numbers with distinct cellular characteristics, were established. We found that mitotic aberrations, such as the delay of mitosis, multipolar centrosomes, and chromosome mis-segregation, were increased in parallel with polyploidy compared to early-passaged hESCs (EP-hESCs) with normal copy number. Through high-resolution genome-wide approaches and transcriptome analysis, we found that culture adapted-hESCs with a minimal amplicon in chromosome 20q11.21 highly expressed TPX2, a key protein for governing spindle assembly and cancer malignancy. Consistent with these findings, the inducible expression of TPX2 in EP-hESCs reproduced aberrant mitotic events, such as the delay of mitotic progression, spindle stabilization, misaligned chromosomes, and polyploidy. These studies suggest that the increased transcription of TPX2 in culture adapted hESCs could contribute to an increase in aberrant mitosis due to altered spindle dynamics.

The prevalence of drug resistance to antiretroviral therapy in the Republic of Mordovia

Objective. To study the causes of virological inefficiency of ART and to analyze the prevalence of mutations of resistance to ART drugs among HIV-infected patients, who lives in the Republic of Mordovia and receiving ART.Materials and methods. We studied 37 blood tests with detectable viral load from HIV-infected patients receiving observation in the GBUZ RM «MRTSPBSPID», taking ART for more than 24 weeks. We The evaluated patient’s adherence to treatment. The analysis for drug resistance was performed by genotyping, using HIV-Resist-Seg diagnostic test systems, (the Federal State Budgetary Institution of the Central Research Institute of Rospotrebnadzor, Russia). Statistical data processing (c2 calculation) StatSoft, Inc. (2011), STATISTICA, Russia.Results and discussion: in the group of patients with mutations of resistance to antiretroviral drugs, mutations of pharmacological resistance to drugs of two and three groups are most often determined (in 87.5% of cases). The number and frequency of genetic aberrations in general did not depend on the number of already approved treatment regimens. At the same time, in patients with two or more changes of ART regimens in the anamnesis, the occurrence of mutations of drug resistance to IP was significantly higher than in HIV-infected patients with one ART regimen.Conclusion: in the Republic of Mordovia, virological inefficiency is associated equally with both a violation of ART intake (poor adherence) and the development of pharmacoresistance. It is important to determine the drug resistance of HIV in patients receiving ART.

Prevalence of Genetic Abnormalities in Patients with Multiple Myeloma and Its Clinical Relevance in a Developing Country like India

Introduction Multiple myeloma (MM) is a malignancy involving terminally differentiated plasma cells. Its incidence in India is about 0.7/1,00,000 population amounting to about 6,800 new cases a year A number of genomic aberrations are associated with MM, most of which confer prognostic significance. Cytogenetic abnormalities are a part of R-ISS score for prognostication which stratifies presence of del(17p), t(4;14) or t(14;16) as stage 3, mSMART is another risk stratification tool which divides MM into high risk and standard risk groups based on genetic aberrations. Hence it is evident that determining the genetic abnormality in MM is important. however, due to limited resources genetic testing is not routinely done and the data in the Indian population is limited. Objective: To estimate the prevalence of molecular cytogenetic abnormalities by Fluorescent in situ hybridization (FISH) analysis in patients with MM and to assess the co-relation with response to induction chemotherapy, relapse and overall survival. Material and Methods: 64 patients were included from January 2016 to December 2019 and followed up till June 2020. Interphase FISH study was performed either at diagnosis or at relapse, on bone marrow aspirate with panel of probes consisting of CKS1B (1q21-22), CDKN2C (1p32.3), D13S319 (13q14.2/13q34), IGH (14q32.33), p53 (17p13.1) and trisomy (5p15/9q22/15q22) (trisomies are considered as hyperdiploidy in this study). Plasma cell purification techniques were not applied prior to FISH analysis. Patients were divided into 2 risk groups; 1) high risk group with presence of del17p, del13q, amplification 1q, del1p and two or more aberrations with either of these and 2) standard risk group with presence of hyperdiploidy or no genetic abnormality. There was no difference in chemotherapy regimen between the 2 groups; 46 (71.8%) received bortezomib-thalidomide-dexamethasone, 10 (15.6%) received bortezomib-cyclophosphamide-dexamethasone, 2(3.1%) received bortezomib-lenalidomide-dexamethasone, 1(1.5%) received daratumumab-bortezomib-dexamethasone and 5(7.8%) received 2 drug chemotherapy. Patients who did not complete minimum follow up of 6 months either due to death or lost to follow up were excluded from the study. Institutional Ethics Committee's approval was taken. Results: Mean age of the population was 60.33 years and male to female ratio was 1.65. 46.87%, 28.13% and 25% of the study population were in the age group of ≤ 60, 61 - 65 and ≥66 years respectively. 12.3%, 43.8% and 43.8% were in R ISS stage 1, 2 and 3 respectively. FISH analysis was done on 61 out of 64 patients (remaining 3 were excluded due to hemodilute bone marrow sample). 22 (36.1%) patients had abnormal genetic aberration on FISH analysis with 10 (16.39%) having two or more abnormalities. The frequency of genetic aberrations was as follows; amplification 1q (13/61, 21.31%), del13q (9/61, 14.75%), hyperdiploidy (7/61, 11.47%), del17p (4/61, 6.55%), IgH rearrangement (3/61, 4.91%), and del1p (1/61, 1.6%). All 3 patients with IgH rearrangement had associated one or more high-risk genetic aberration and hence were included in high risk group. 31.1% of the patients were high risk and 68.9% were standard risk. The response to induction chemotherapy, incidence of relapse, time to 1st relapse and total number of relapses are shown in (table;1) and there was no significant difference between high risk and standard risk group. Overall survival in standard risk group at 2 and 5 years was 89.6% ± 5.8% and 78.6% ± 13.9% and in high risk group was 60.7% ± 13.2% and 29.5% ± 23.1% respectively (p value: 0.762). Overall survival was significantly lower in age group ≥66 years as compared to age group ≤ 60 years and 61 - 65 years (p value 0.001) and it was also significantly lower in R ISS stage 3 as compared to R ISS stage 1 and 2 (p value 0.006). Conclusion: More than one third patients of MM (36.1%) showed genetic abnormality, amplification 1q being the most frequent. Overall survival was significantly lower in older age group and R ISS stage 3 patients. Response to induction chemotherapy and relapse rate were similar in high and standard risk groups. Although overall survival was lower in high risk group, it was statistically not significant. This study highlights the importance of FISH analysis for disease stratification and prognostication which should be routinely practiced. Disclosures No relevant conflicts of interest to declare.

CLL-132: Mutational Status of IGVH in Correlation with Genetic Abnormalities of Patients with Chronic Lymphocytic Leukemia in Macedonia - A Single-Centre Experience

Context B-cell chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. One of the most important molecular predictors, the immunoglobulin VH gene mutational status, divides CLL into two prognostic groups, where unmutated U-CLL is associated with remarkably worse prognosis than mutated M-CLL. In many studies, multiple recurring chromosomal aberrations appear to be effective prognostic markers in CLL. Objective The aim of the study was first-time evaluation of rearrangement of IG genes and genetic abnormalities in Macedonian CLL patients. Design Prospective study of Macedonian patients with CLL at early and advanced stage of disease in a period of time from January 2011 to January 2019. The median follow-up was 48 months (1-96 months). Setting Mutational status and configuration of IGHV-IGHD-IGHJ rearrangements in 90 treatment-naive CLL patients were analyzed using reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing methodology. We used multiplex ligation-dependent probe amplification (MLPA) for detection of most common genetic abnormalities. Interventions We introduced prognostic markers like cytogenetic aberrations, and mutational status of immunoglobulin heavy chain in prognostic stratification of Macedonian patients with CLL. Results Our evaluation has shown that 54.7% patients belonged to the U-CLL subset, whereas 45.3% belonged to the M-CLL subset. The most frequently expressed IGHV subgroup was IGHV3 (40%), followed by IGHV4 (29%), IGHV1(27%), and IGHV5 (3%). The most frequent subgroup with 8% were IGHV1-69*13 and IGHV4-34*0. In the IGHD and IGHJ sets, most frequently expressed genes were IGHD3 (59.7%) and IGHJ6(53.1%), respectively. We found that 80% of IGHV1, 65.6% of IGHD3, and 83.3% of IGHJ6 genes were U-CLL (p=0.0005). Frequency of genetic aberrations by MLPA were 13q14 deletion (20%) followed by 11q deletion (14%), then trisomy 12 (13%) and 17p deletion (6.6%), multiple mutations (6.7%), and NOTCH mutation (5.3%). Conclusions Our evaluation of mutational status on IGVH, IGDH, and IGJH genes in Macedonian CLL patients resulted with data that are consubstantial to those from the Mediterranean area. Novel mutations discovered in this study must be validated through large cohort studies and may offer clues to the mechanisms underlying the difference in CLL survival. In the future, therapeutic strategies targeting these genes should be evaluated and considered.

STAT3 Expression and Clinical Implications In De Novo Diffuse Large B-Cell Lymphoma: A Report From The International DLBCL Rituximab-CHOP Consortium Program

IntroductionExpression of signal transducer and activator of transcription 3 (STAT3) in de novo diffuse large B-cell lymphoma (DLBCL) has not been studied broadly and the prognostic value of STAT3 expression in DLBCL is controversial. MethodsThe study group included 876 de novo DLBCL patients. All patients were treated with rituximab, cyclophosphamide, hydroxydoxorubicin, vincristine and prednisone (R-CHOP). Cases excluded from the study group included large cell transformation from low-grade B-cell lymphoma, primary cutaneous large B-cell lymphoma, primary mediastinal large B-cell lymphoma, primary DLBCL of the central nervous system and cases associated with Epstein-Barr virus or human immunodeficiency virus. Immunohistochemical (IHC) studies for several biomarkers were performed using fixed, paraffin embedded sections of tissue microarrays. Fluorescence in situ hybridization (FISH) for BCL2, BCL6, MYC, and TP53 were performed andTP53 was also sequenced Gene expression profiling (GEP) was performed on 500 cases and the cell of origin (COO) classification was determined by GEP (gold standard) and immunohistochemistry. ResultsSTAT3 was positive in 240 (32.9%) patients, including 133 men and 107 women. The median age of STAT3+ DLBCL patients was 65 years (range, 21-93) and was similar to STAT3- DLBCL patients (63, range 12-95). B symptoms (44.4% vs. 35.2%, P=0.021) and advanced stage (60.5% vs. 52.1%, P=0.035) were more commonly present in STAT3+ DLBCL compared with STAT3- DLBCL patients. Other clinical characteristics were similar between the groups. STAT3+ DBLCLs were more often activated B-cell (ABC) type than STAT3- DLBCLs (61.8% vs. 41.1%, P<0.001). STAT3+ DLBCLs more often expressed MYC (76.7% vs. 56.5%, P<0.001), p50 (43.3% vs. 34.1%, P=0.018), and p65 (33.9% vs. 25.3%, P=0.017) than STAT3- DLBCLs. c-Rel, however, was less commonly expressed in STAT3+ DLBCL (18.9% vs. 27.2%, P=0.018). Expression of BCL2 was similar between the two groups. Genetic aberrations involving BCL2 (10.9%), MYC (7.6%) and TP53 deletion (8.1%) by FISH were uncommon. Aberrations of BCL6 were present in 24.6% of STAT3+ DLBCL. TP53 mutation was found in 27 patients (20.1%). The frequency of genetic aberrations by FISH was similar in the STAT3+ and STAT3- DLBCL groups. Patients with STAT3+ versus STAT3- DLBCL had similar OS (P=0.494) and PFS (P=0.224). When looking at all DLBCL cases divided into GCB versus ABC type, STAT3 expression did not predict survival in the GCB (OS, P=0.945 and PFS, P=0.604) or ABC types (OS, P=0.211 and PFS, P=0.079, respectively). In multivariate analysis, STAT3 expression did not show an increased hazard ratio (HR 0.806, 95% CI 0.578-1.125, P=0.205). ConclusionSTAT3 is expressed in approximately 1/3 of de novo DLBCLs. STAT3 expression is associated with B symptoms, advanced stage of disease, ABC type, and expression of MYC. Expression of p50 and p65 are more frequently expressed in STAT3+ DLBCL, illustrating activated NF-κB through canonical pathway. C-Rel is less commonly expressed in STAT3+ DLBCL, suggesting p65 is the principal partner for p50. Genetic aberrations are rare. Although STAT3 expression is associated with several adverse prognostic parameters, it does not confer inferior OS and PFS in DLBCL overall, suggestive of the presence of yet unidentified putative tumor suppressive functions in STAT3+ DLBCL patients. Disclosures:Winter:Millenium: Research Funding; Novartis : Research Funding; Pfizer (Wyeth): Research Funding; Seattle Genetics: Research Funding; Spectrum: Research Funding; Janssen (Pharmacyclics): Research Funding; Spectrum (Allos): Consultancy; Sanofi Aventis: Consultancy; Tgen: Consultancy; AMBIT Biosciences (Spouse): Research Funding; Celgene (Spouse): DSMB, DSMB Other, Research Funding; Ariad Pharmaceuticals (Spouse): Research Funding; Novartis (Spouse): Consultancy, Research Funding; Amgen (Spouse): Consultancy, Research Funding; Astellas (Spouse): Research Funding; Caremark/CVS: Consultancy; Pfizer (Spouse): Consultancy; Sanofi Aventis (Spouse): DSMB, DSMB Other; Bristol Myers Squibb (Spouse): DSMB, DSMB Other; UptoDate, Inc.(Spouse): Patents & Royalties.

Frequency of genetic aberrations in mucosa-associated lymphoid tissue lymphoma of different sites

To study the frequency of certain specific genetic aberrations, including t (11; 18)/API2-MALT1, t (1; 14)/IgH-bcl-10 and t (14; 18)/IgH-MALT1, in mucosa-associated lymphoid tissue (MALT) lymphoma of different sites. One hundred and ninety-six cases of MALT lymphoma from Cancer Hospital of Fudan University were enrolled into the study. The samples consisted of MALT lymphomas from stomach (53 cases, including 44 cases of low-grade MALT lymphoma and 9 cases of MALT lymphoma with diffuse large B-cell lymphoma component), ocular adnexa (50 cases), salivary gland (20 cases), lung (20 cases), intestine (17 cases), skin (17 cases), liver (8 cases), thyroid (5 cases) and other sites (2 cases from tongue, 1 case from pancreas, 1 case from larynx, 1 case from vocal cords and 1 case from kidney). Fluorescence in-situ hybridization for API2-MALT1 fusion gene, bcl-10, MALT1 and IgH genes was performed on paraffin sections. Among the 196 cases of MALT lymphoma, 25 cases (12.8%) possessed API2-MALT1 fusion gene. The positive rates in various sites were significantly different (P = 0.002), as follows: 45.0% (9/20) in lung, 22.7% (10/44) in stomach (without large cell component), 15.0% (3/20) in salivary gland, 2 of 17 cases in intestine and 2.0% (1/50) in ocular adnexa. The fusion gene was not detected in the 9 cases of gastric MALT lymphoma with large cell transformation. It was also negative in the MALT lymphomas from skin, thyroid and other sites. One of the pulmonary MALT lymphoma cases showed simultaneous aberrations of IgH and MALT1 genes, such as t (14; 18)/IgH-MALT1. Two of the gastric MALT lymphoma cases without large cell transformation and one of the pulmonary MALT lymphoma cases showed aberrations in both IgH and bcl-10 genes, such as t (1; 14)/IgH-bcl-10. Six cases of MALT lymphoma, including 2 cases from salivary gland, 2 cases from liver, 1 case from thyroid and 1 case from stomach (large cell transformation), showed trisomy 18. On the other hand, 3 cases, including 2 cases from stomach and 1 case from intestine, showed MALT1 gene amplification. In general, specific genetic aberrations have a relatively low frequency of occurrence in MALT lymphomas. The positive rates however show a remarkable difference in tumors of different anatomic sites. This phenomenon may suggest that MALT lymphomas in different sites, though sharing similar morphologic features, may have a divergent tumorgenesis.