Cytogenetics in Acute Lymphoblastic Leukaemia Patients: A Retrospective Study from a Teaching Hospital in Karnataka, India

Abstract

Introduction: Cytogenetic assessment is an essential test in patients with Acute Lymphoblastic Leukaemia (ALL), as it is required for diagnosis, treatment and to know the prognosis. Although these tests are done as standard of care in most of the institutes, there are limited publications from India describing karyotypic abnormalities in ALL patients. Aim: To assess the various cytogenetic abnormalities encountered in patients suffering from ALL and to know the pattern of chromosomal abnormalities. Materials and Methods: The present study was a retrospective cross-sectional study done at a tertiary care teaching hospital in Karnataka, India. Patients who were diagnosed with ALL based on flow cytometry between January 2017 and June 2021 were included in the present study and total 61 patients were evaluated for the cytogenetic findings. The medical records of these 61 patients were reviewed to collect their details like age, sex, immunophenotype and cytogenetic findings. Results: During flow cytometry analysis, side scatter vs CD45 expression strategy was applied. Events with low side scatter and dim CD45 expression (blast gate) were gated. Leukaemias expressing precursor markers (CD34/HLA-DR) along with cytoplasmic/surface CD3 were diagnosed as T-ALL. Leukaemias with precursor markers along with any two out of three B-cell markers i.e CD19, CD79a or CD10 were diagnosed as B-ALL. In this study 13 patients out of 35 had normal karyotype and this was the most common cytogenetic finding. The most common cytogenetic abnormality in B-ALL patients was hypodiploidy, but t(9;22) (q34;q11.2) was the most common cytogenetic abnormality in adult patients with B-ALL. Among the patients with T-ALL, only 2 (15.38%) patients had chromosomal abnormalities. Conclusion: The present study highlights the role of cytogenetics in patients undergoing treatment for ALL. Chromosomal abnormalities like t(9;12) (q13;p11.2), t(X;1) (q13;p36.1) and t(9;15) (p13;q11.2) are novel chromosomal abnormalities which were found in the present study. Long-term follow-up is necessary to identify prognostic implications of such chromosomal abnormalities.