PTEN、MLL基因在T淋巴母细胞淋巴瘤／白血病的表达及其意义

 目的　分析肿瘤抑制基因PTEN、混合系白血病（MLL）基因等在T淋巴母细胞淋巴瘤／白血病（T-LBL／ALL）的表达及意义。方法　选用76例T-LBL／ALL患者淋巴结存档蜡块，应用免疫组织化学EnVision法进行PTEN标记，用20例反应性增生淋巴结标本作正常对照。并用荧光原位杂交（FISH）技术检测MLL基因所在11q23染色体的断裂和扩增情况。结果　76例T-LBL／ALL中，PTEN的表达率为64.47 %（49／76），低于淋巴结反应性增生的100 %（20／20）（χ2＝19.220，P＜0.05）。PTEN表达与临床分期、Ki-67、乳酸脱氢酶（LDH）呈负相关（P＜0.05）。76例T-LBL／ALL中，MLL基因发生11q23染色体断裂13例（17.11 %），扩增18例（23.68 %）。MLL基因断裂组总体生存率（25.0 %）低于非断裂组（43.6 %）（χ2＝11.357，P＜0.05）。MLL基因扩增组总体生存率（17.1 %）低于非扩增组（42.7 %）（χ2＝4.533，P＜0.05）。结论　抑癌基因PTEN表达降低在T-LBL／ALL的发生发展中可能具有重要作用。MLL基因发生染色体11q23断裂和扩增有助于对T-LBL／ALL预后的判断，发生MLL基因断裂或扩增的T-LBL／ALL预后较差，提示MLL基因断裂或扩增可能为T-LBL／ALL的一种分子亚型。

Significance and expression of PTEN, MLL gene in T lymphoblastic lymphoma/leukemia

Objective To investigate the significance and expression of PTEN, MLL in T lymphoblastie 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 1 lq23） was performed to detect its breakage and amplification. Results Among the 76 cases of T- LBL/ALL, the positive rate of PTEN was 64.47 % （49/76）, lower than that in reactivated lymphoid tissue （100 %, 20/20） （X^2= 19.220, P 〈0.05）. PTEN expression was reversely correlated to the clinical 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 of 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 （ X 2 = 11.357, X^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-LBIdALL.