急性白血病患者p16及p15基因纯合子缺失及甲基化研究

目的　探讨血液系统恶性肿瘤患者ｐ１６ 及ｐ１５ 基因失活的发生率及其临床意义。方法　用聚合酶链反应（ Ｐ Ｃ Ｒ） 方法扩增ｐ１６ 及ｐ１５ 基因外显子１ 及外显子２ ，检测等位基因纯合子缺失；再用限制性内切酶 Ｐ Ｃ Ｒ 方法检测ｐ１６ 及ｐ１５ 基因甲基化； 然后用 Ｔ Ｕ Ｎ Ｅ Ｌ 法（ Ｔｄ Ｔｍｅｄｉａｔｅｄ ｄ Ｕ Ｔ Ｐｄｉｇｏｘｙｇｅｎｉｎ ｅｎｄｌａｂｅｌｉｎｇ） 检测细胞凋亡。结果　５６ 例患者中有ｐ１６ 和（ 或）ｐ１５ 基因失活者共３３ 例，其中急性淋巴细胞白血病（ Ａ Ｌ Ｌ）３８ 例中２３ 例（ 占６０ ．５ ％ ， Ｔ Ａ Ｌ Ｌ１２ 例， Ｂ Ａ Ｌ Ｌ１１ 例） ， Ａ Ｎ Ｌ Ｌ１８ 例中１０ 例（ 占５５５ ％ ） 。 Ａ Ｌ Ｌ 患者ｐ１６ 及ｐ１５ 基因均以甲基化失活为主。 Ｔ Ａ Ｌ Ｌ 失活的频率比 Ｂ Ａ Ｌ Ｌ 高。有ｐ１６ 和（ 或）ｐ１５ 基因失活者， 细胞的凋亡比例明显减少，病情进展迅速，治疗效果差，缓解率低， 缓解期明显缩短。结论　ｐ１６ 及ｐ１５ 基因失活的检测对于探讨急性白血病的发病机制，判断疾病进程有重要意义。

Homozygous deletion and methylation of p16 and p15 gene in acute leukemia

Objective To investigate the frequency of p16 and p15 gene inactivation in acute leukemia and to evaluate its clinical significance. Methods Fifty six patients with newly diagnosed acute leukemia was studied. PCR technique was used to detect homozygous deletion of p16 and p15 gene, restriction enzyme PCR technique was used to detect gene methylation, and TdT mediated dUTP digoxygenin end labeling (TUNEL) technique was used to detect cell apoptosis. Results p16 and /or p15 gene inactivation was detected in 33 of the 56 patients,including 23/38 (60.5%) of the ALL patients (T ALL 12/16, B ALL 11/22) and 10/18(55.5%) of the ANLL patients. For ALL patients, methylation was the major pathway of p16 and p15 gene inactivation. Patients with p16 and/or p15 gene inactivation had a delayed apoptosis, a poor response to chemotherapy, a lower remission rate and a shortened remission duration. Conclusion The inactivation of p16 and p15 gene plays a key role in the pathogenesis of acute leukemia.