Acute lymphoblastic leukaemia is the most common hematopoietic malignancy in childhood, comprising of B-cell lineage (85%) and T-cell lineage (15%). Recent studies have identified a subtype of T-cell acute lymphoblastic leukaemia (T-ALL) termed “early T-cell precursors (ETP)” recognised as a new provisional entity in 2016 update to the World Health Organization (WHO) classification of acute leukaemia, early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is characterized by a unique immunophenotype and genetic profile and its origin has been found to be from migration of cells from thymus to bone marrow. Hence, our study aims at reporting the prevalence of ETP-ALL among immunophenotypically categorised acute T-cell lymphoblastic leukaemia cases. Present work is a retrospective observation of acute T-cell lymphoblastic leukemias and reporting ETP-ALL cases seen during the period of over two years (from August 2018 to August 2020) received for flowcytometry in the department of Pathology, PGIMS, Rohtak, Haryana. Peripheral blood showed features of acute leukemia and immunophenotyping was performed. Fourteen cases were received for flowcytometry showing features of acute leukemia and immunophenotyping was performed revealing two ETP-ALL cases with positivity for cytCD3, CD7 (T-cell markers), HLA-DR, CD13 (myeloid marker-aberrant expression), sCD34, CD117 (stem cell markers), CD19 (B-cell marker) and dim expression of CD45. This study is a supportive data for immunophenotypic identification of ETP-ALL cases in centres where genetic study and other ancillary techniques are not available. It needs to be differentiated from non ETP-ALLs as this entity has been reported to show treatment failure with the treatment modalities for non ETP-ALLs.
Risk factors and outcomes in children with high-risk B-cell precursor and T-cell relapsed acute lymphoblastic leukaemia: combined analysis of ALLR3 and ALL-REZ BFM 2002 clinical trials