Immunological Subtypes of Acute Lymphoblastic Leukemia- Beyond Morphology: Experience from Kidwai State Cancer Institute, Bengaluru, India.

INTRODUCTION Acute lymphoblastic leukemia (ALL) is disease of lymphoid precursors and is the most common cancer. Diagnosis of ALL is made by evaluating morphology and flowcytometric Immunophenotyping (FCI)and is an important adjunct in diagnosis and determining treatment in ALL, with availability of extensive monoclonal antibodies in the recent years there is tremendous progress in the field of FCI, and is a requirement by World Health Organisation for the classification of acute lymphoblastic Leukemia. Flow cytometric immunophenotyping of the leukemic blasts helps in categorization of acute lymphoblastic leukemia as B-ALL or T-ALL. Though ALL is the most common cancer, there is paucity of study in Indian scenario, and very few reports of immunologically subtyping of ALL is reported. AIM To confirm the clinical/morphological diagnosis and to determine immunological subtype of acute lymphoblastic leukemia as per requirement by World Health Organization for the classification of acute lymphoblastic leukemia. MATERIAL AND METHODS At Kidwai State Cancer institute, Bangalore, we have performed of Immunophenotyping in 1425 untreated cases of acute leukemias during January 2012 - August 2015. RESULTS Flow cytometry analysis of 1425 cases of acute Leukemias were performed, 918 (64.42%) were acute lymphoblastic Leukemia, 688 were B-ALL (74.94%), majority(480) of B-ALL were in children (69.76%), 230 were T-ALL (25.05 %), B-ALL was the most common subtype of acute leukemias. CONCLUSIONS Acute lymphoblastic leukemia is the most common leukemia in adults and children. Immunophenotping helps in confirming the clinical/morphological diagnosis and in determining the immunological subtype of acute lymphoblastic leukemia, thus has an important role in deciding on the treatment regime. ALL is the disease of lymphoid precursors and is more common cancer in children than adults. B-ALL was the most common subtype of acute leukemias both in adults and in children. T-ALL is less common in pediatric population. Flowcytometric techniques are used to measure (submicroscopic) minimal residual disease (MRD), and is currently incorporated in many ALL treatment protocols as a tool for risk stratification.