Poor Response to Standard Chemotherapy in Early T-precursor (ETP)-ALL: A Subtype of T-ALL Associated with Unfavourable Outcome: A Brief Report.

Early T-precursor (ETP)-ALL, a type of T-ALL, is a new pathobiologic entity with distinct immunophenotype (CD1a(-), CD8(-), CD5(weak/absent) with stem-cell/myeloid markers) and genetic expression, poor response to standard intensive chemotherapy and very high risk of relapse. The genetic mutations typically associated with the pathogenesis of acute myeloid leukemia are seen with increased prevalence in ETP-ALL. No Indian data exists regarding this rare entity. Recently we have seen six cases of ETP-ALL and hereby reporting their clinical characteristics and treatment outcome. All patients were given induction chemotherapy according to standard protocols. Only one out of six patients could achieve remission after induction therapy. Rest five patients died because of their leukemia. This reflects the aggressive biology of this disease and its poor response to standard chemotherapy regimens generally used in T-ALL. The limited experience with ETP-ALL reflects whether rarity of this condition or failure to recognize this is not clear at this time. More studies are required to understand the basic biology of this disease and new therapeutic strategies need to be devised.