Observation on frequency & clinico-pathological significance of various cytogenetic risk groups in multiple myeloma: an experience from India

Cytogenetic Abnormalities in Multiple Myeloma: Incidence, Prognostic Significance, and Geographic Heterogeneity in Indian and Western Populations

Multiple myeloma (MM) is a genetically complex and heterogeneous neoplasm in which cytogenetics is a major factor playing an important role in the risk stratification of disease. High-risk MM based upon cytogenetic classification includes primary IGH translocations t(4;14), t(14;16), t(14;20), and secondary progressive aberrations such as gain/amp(1q), 1p deletion, del(17p), and hypodiploidy. Several studies have proved that interphase FISH can detect primary as well as secondary cryptic aberrations very efficiently in lowest 5-10% abnormal plasma cell population. The present large-scale study was undertaken to evaluate the incidence of cytogenetic abnormalities, to analyse the correlation of conventional karyotyping with FISH, and to seek the geographic heterogeneity in the incidence of primary as well as secondary aberrations in our Indian versus Western populations. We conducted prospective studies of 1,104 patients consecutively referred from the primary, secondary, and tertiary oncology centres from all over India. Interphase FISH was performed on isolated plasma cells. Karyotype analysis was done as per ISCN 2016 and 2020. FISH could detect cytogenetic abnormalities in 67.6% of the cases with an incidence of 59% non-hyperdiploidy. The incidence of IGH translocation was 26% versus literature frequency of 40-50% which was mainly due to a low incidence (6%) of t(11;14) in contrast to 15-20% in other series. Additionally, the association of secondary progressive aberrations in the hyperdiploid group rather than the non-hyperdiploid group in our patients is not a common finding. A biallelic inactivation of TP53 as an ultra-high risk factor was detected in old-aged patients. These observations disclose the novel findings and strongly indicate the racial disparity which leads to geographic heterogeneity. In contrast to FISH, conventional karyotyping could detect MM-related aberrations in 50% of cases, of which 44% revealed highly complex karyotypes with common aberrations of chromosome 1q. Overall, FISH was found to be a novel, easy approach with high success rate and capability of detection of all cytogenetic abnormalities that add valid information for the risk stratification of disease. This, in future, in combination with mutation profile and gene expression profile will help in further refinement of disease and identification of actionable targets.

Cytogenetics and Revised International Staging System (R-ISS): Risk Stratification in Multiple myeloma - A Retrospective Study in Indian Population

Background & Objective:

Cytogenetic abnormalities in Multiple myeloma (MM) has emerged as the most important factor that determine the prognosis and survival. Fluorescence in situ hybridization (FISH) can detect a greater number of cytogenetic abnormalities as compared to conventional karyotyping and hence has become the standard test in determining genetic abnormalities in MM. The present study was planned as there is an unmet need to find out various cytogenetic abnormalities and to implement them in prognostic stratification by Revised International Staging System (R-ISS) among Indian population.

Methods:

A single institution retrospective study was conducted among a total of 117 patients newly diagnosed as Multiple Myeloma. They were analyzed for various cytogenetic abnormalities by using interphase FISH (iFISH) and were staged according to Revised International Staging System (R- ISS).

Results:

Out of the 117 patients studied, deletion 17p13 (p53) was present in 16 patients (13.67%). Thirty patients (25.64%) showed deletion 13q14.3. Three patients (2.56%) were detected to have t(4:14).Two patients (1.7%) had t(11:14) and t(14:16), respectively. Total of 19 patients (16.23%) in our study exhibited high risk cytogenetics and two among them had more than one high risk cytogenetic abnormalities. There was a 66.4% moderate correlation between ISS-III and high-risk cytogenetics which was statistically insignificant. Of the total 117 patients, 37 (31.62%) were staged R-ISS III.

Conclusion:

High risk cytogenetics was found in 16.23 % of our study population and del 17p13 was the most common high-risk cytogenetic abnormality. Of the studied subjects, 31.62% had R-ISS III, which is significantly higher compared to western population.

Cytogenetic Abnormalities in Multiple Myeloma Patients at a Tertiary Healthcare Center in India

Objective:

Multiple myeloma (MM) is a clinically and genetically heterogeneous plasma cell neoplasm. The prognosis of MM patients is dependent on several factors including the patient’s age, the stage of disease and genetic alterations. This study aimed to determine the frequency of common chromosomal abnormalities and their significance in MM patients referred to a tertiary healthcare center in India.

Methods:

Fluorescence in situ hybridization on interphase nuclei from bone marrow cells using seven MM-specific probes for recurrent aberrations was performed in a total of 215 newly diagnosed patients.

Results:

Chromosomal abnormalities were detected in 161 (74.9%) MM patients in this study. The most frequent aberration was trisomy(ies) involving only gain of chromosomes in 48 (22.3%) cases. A translocation involving the IGH gene alone or accompanied by trisomy(ies) or by monosomy 13/13q deletion or by both was registered in 80 (37.2%) patients. Atypical patterns such as a deletion of the IGH variable segment (IGHv) on the derivative chromosome 14 or on the native (normal) chromosome 14, biallelic deletion of IGHv, deletion of the IGH constant segment on the rearranged chromosome14 and extra fusions were noticed in 21 (9.8%) patients with an IGH rearrangement. Monosomy 13/deletion 13q was identified singly or as part of a complex karyotype in 74 patients (34.4%). Clonal heterogeneity and additional abnormalities including TP53 deletion and monosomies of chromosomes 4, 9, 14 and 16 were recorded in 18.6% and 16.3% of patients respectively. Patients with abnormalities exhibited plasmacytosis, reduced hemoglobin value and high level of ß2-microglobulin.

Conclusions:

A lower median age and a low frequency of IGH translocations particularly t(11;14) and chromosome 13 abnormalities suggest ethnic diversity. Further investigations on genetic alterations including IGH deletions will contribute to improved insights into the biology of myeloma disease, risk stratification and patient management.

Plasma Cell Dyscrasias in India-2017 Updates

Rapid advances are being made in the field of plasma cell dyscrasias. Many abstracts pertaining to the laboratory aspects, clinical features, treatment modalities and outcome of plasma cell dyscrasias were presented at Hematocon 2017. All the total of 24 abstracts pertaining to plasma cell dyscrasias presented at the Hematocon 2017 were reviewed. Out of them 10 were original research and 14 were case reports/short case series. The key findings of original research studies conducted in India are being summarized. Exciting research in the field of plasma cell dyscrasias is being carried out by various centers in the country. Data presented on various aspects of research in plasma cell disorders is encouraging. Multicentric research in the field plasma cell dyscrasias should be encouraged to highlight the various aspects of disease biology and challenges in management unique to our country.

Comparison of Diagnostic Yield of a FISH Panel Against Conventional Cytogenetic Studies for Hematological Malignancies: A South Indian Referral Laboratory Analysis Of 201 Cases

Objectives:

Genetic markers are crucial fort diagnostic and prognostic investigation of hematological malignancies (HM). The conventional cytogenetic study (CCS) has been the gold standard for more than five decades. However, FISH (Fluorescence in Situ Hybridization) testing has become a popular modality owing to its targeted approach and the ability to detect abnormalities in non-mitotic cells. We here aimed to compare the diagnostic yields of a FISH panel against CCS in HMs.

Methods:

Samples of bone marrow and peripheral blood for a total of 201 HMs were tested for specific gene rearrangements using multi-target FISH and the results were compared with those from CCS.

Results:

Exhibited a greater diagnostic yield with a positive result in 39.8% of the cases, as compared to 17.9% of cases detected by CCS. Cases of chronic lymphocytic leukaemia (CLL) benefited the most by FISH testing, which identified chromosomal aberrations beyond the capacity of CCS. FISH was least beneficial in myelodysplastic syndrome (MDS) where the highest concordance with CCS was exhibited. Acute lymphocytic leukaemia (ALL) demonstrated greater benefit with CCS. In addition, we found the following abnormalities to be most prevalent in HMs by FISH panel testing: RUNX1 (21q22) amplification in ALL, deletion of D13S319/LAMP1 (13q14) in CLL, CKS1B (1q21) amplification in multiple myeloma and deletion of EGR1/RPS14 (5q31/5q32) in MDS, consistent with the literature.

Conclusions:

In conclusion, FISH was found to be advantageous in only a subset of HMs and cannot completely replace CCS. Utilization of the two modalities in conjunction or independently should depend on the indicated HM for an optimal approach to detecting chromosomal aberrations.