Prognostic importance of TLX1 (HOX11) oncogene expression in adults with T-cell acute lymphoblastic leukaemia

The activation of oncogenic transcription factors defines distinct molecular subsets of T-cell acute lymphoblastic leukaemia and has prognostic relevance in children. We investigated the prognostic effect of the expression levels of eight oncogenic transcription factors - TLX1 (HOX11), TLX3 (HOX11L2), TAL1, TAL2, LYL1, OLIG2 (BHLHB1), LMO1, and LMO2 - in 52 adults with T-cell acute lymphoblastic leukaemia. The leukaemia-specific survival rate for the 16 TLX1-positive patients was 88% (90% CI 73-100%), compared with 56% (42-70%) for all other cases (p=0.019). Only the TLX1 oncogene expression subgroup showed difference in leukaemia-specific survival. Our results suggest that overexpression of TLX1 confers a good outlook for adults with T-cell acute lymphoblastic leukaemia. Furthermore, our findings lead to questions about whether stem-cell transplantation in first remission is necessary for effective treatment of patients in the low-risk subgroup of patients with TLX1 oncogene expression.