SIL-TAL1 fusion gene negative impact in T-cell acute lymphoblastic leukemia outcome

SIL-TAL1 fusion gene and the ectopic expression of HOX11L2 are common molecular abnormalities in T-cell acute lymphoblastic leukemia (T-ALL). To verify their influence on outcome, we analyzed a Brazilian pediatric T-ALL series of cases. One hundred and ninety two children, age ranged 0-21 years old, were consecutively diagnosed and treated. Reverse transcriptase-polymerase chain reaction (RT-PCR) technique was used to identify the molecular alterations. Kaplan-Meyer method was applied to estimate overall survival. The most frequent maturation stage was T-IV (40.1%), and 30.7% of cases were CD10(+). SIL-TAL1(+) and HOX11L2(+) accounted for 26.7% and 10.3% of the cases, respectively. The overall survival (OS) was 74% in 80-month follow-up. HOX11L2(+) was not predictive factor for outcome. Considering patients younger than nine years-old, those with SIL-TAL1(+) presented a poorer outcome (p = 0.02). The results of this study suggest that in the Brazilian population only the presence of SIL-TAL1 can predict outcome in a restricted group of patients.