Chromosome-1 abnormalities in Childhood B-Lymphoblastic Leukemia - An analysis with reference to clinical variables and survival outcome.

Abstract

Chromosome-1 abnormalities (C1As) are common genetic aberrations in hematological malignancies. We sought to evaluate significance of these abnormalities with reference to clinical characteristics and survival outcome in a pediatric B-Lymphoblastic Leukemia (B-ALL) cohort. This is a retrospective study conducted in cytogenetic section of Indus Hospital and Health Network. Data was retrieved from October 2020 to July 2022 for childhood B-ALL cases exhibiting C1As. Chromosome analysis was performed on Cytovision MB8 using G-banded metaphases derived from unstimulated bone marrow culture. Results were recorded according to the International System for Human Cytogenetic Nomenclature (ISCN-2020). Data analyzed using SPSS, version 24.0. C1As were observed in 60/450 (13.3%) cases of B-ALL. Among C1As, 29 (48%) cases had t(1;19). There were 13 (45%) balanced and 16 (55%) unbalanced translocations. The aberrations without t(1;19) were seen in 31 (52%) cases including 1q duplication with hyperdiploidy in 14 (45%) cases. The median age for C1As with and without t(1;19) was eight years and six years while the median leukocyte count was 32 x 109/L vs. 17 x 109/L. Event-free survival (EFS) for cases with and without t(1;19) was 69% and 74.2% respectively. Despite the fact that the t(1;19) positive group had a higher median age, a higher white cell count and more CNS positives, the difference in EFS is statistically insignificant when compared to the t(1;19) negative cases. Furthermore, we found a survival difference between balanced and unbalanced t(1;19) groups, which is statistically insignificant but warrants large-scale prospective studies for further understanding.