Significance and expression of PTEN, MLL gene in T lymphoblastic lymphoma/leukemia / 白血病·淋巴瘤

ABSTRACT

Objective To investigate the significance and expression of PTEN, MLL in T lymphoblastic lymphoma/leukaemia(T-LBL/ALL). Methods Seventy-six cases of T-LBL/ALL were studied by using immunohistochemical EnVision method for PTEN. Fluorescence in-situ hybridization (FISH) for MLL gene (located on chromosome 11q23) was performed to detect its breakage and amplification. Results Among the 76 cases ofT- LBL/ALL, the positive rate of PTEN was 64.47 % (49/76), lower than that in reactivated lymphoid tissue (100 %, 20/20) (λ2= 19.220, P ＜0.05). PTEN expression was reversely correlated to theclinical stage, Ki-67 index and LDH level (P ＜0.05). Among the 76 cases, MLL gene with breakage of 11q23 was detected in 13 cases (17.11%), and amplification in 18 cases (23.68 %). Survival rate ot MLL gene breakage group was lower than that of non-breakage group (25.0 %, 43.6 %). Survival rate of MLL gene amplification group was lower than that of non-amplification group too (17.1%, 42.7 %). Both of breakage and amplification were related to prognosis ( λ 2 = 11.357, λ 2 = 4.533; P ＜0.05). Conclusion Anti-oncogene PTEN down-regulation may play an important role on the development and proceeding of T-LBL/ALL. MLL gene with breakage and amplification of 11q23 are helpful to predict prognosis of T-LBL/ALL. The case with MLL gene breakage and amplification of T-LBL/ALL may have a poor prognosis. It hints this group maybe a subtype of T-LBL/ALL.