Frequency of Chromosomal Abnormalities in Pakistani Adults with Acute Lymphoblastic Leukemia


Background: The difference in prognosis of adult and childhood acute lymphoblastic leukemia (ALL) can beattributed largely to variation in cytogenetic abnormalities with age groups. Cytogenetic analysis in acute leukemiais now routinely used to assist patient management, particularly in terms of diagnosis, disease monitoring,prognosis and risk stratification. Knowing about cytogenetic profile at the time of diagnosis is important in orderto take critical decisions in management of the patients. Aim and
Objectives: To determine the frequency ofcytogenetic abnormalities in Pakistani adult patients with ALL in order to have insights regarding behavior ofthe disease. Materials and
Methods: A retrospective analysis of all the cases of ALL (≥15years old) diagnosed atAga Khan University from January 2006 to June 2014 was performed. Phenotype (B/T lineage) was confirmedin all cases by flow cytometry. Cytogenetic analysis was made for all cases using the trypsin-Giemsa bandingtechnique. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature(ISCN) criteria.
Results: A total of 166 patients were diagnosed as ALL during the study period, of which 151samples successfully yielded metaphase chromosomes. The male to female ratio was 3.4:1. The majority (n=120,72.3%) had a B-cell phenotype. A normal karyotype was present in 51% (n=77) of the cases whereas 49% (n=74)had an abnormal karyotype. Of the abnormal cases, 10% showed Philadelphia chromosome; t(9;22)(q34;q11.2).Other poor prognostic cytogenetic subgroups were t(4;11)(q21;q23), hypodiploidy (35-45 chromosomes) andcomplex karyotype. Hyperdiploidy (47-57 chromosomes) occurred in 6.6%; all of whom were younger than 30years.
Conclusions: This study showed a relatively low prevalence of Philadelphia chromosome in Pakistaniadults with ALL with an increase in frequency with age (p=0.003). The cumulative prevalence of Philadelphianegativepoor cytogenetic aberrations in different age groups was not significant (p=0.6).