目的 探讨抑癌基因p27^kip1和细胞周期蛋白Ki-67在原发性中枢神经系统生殖细胞肿瘤(CNSGCTs)中的表达及其临床病理学意义。方法 采用免疫组织化学方法检测28例原发性CNSGCTs组织中p27^kip1和Ki-67的表达，计算Ki-67增殖指数（Ki-67 LI）。结果 28例原发性CNSGCTs中，17例（60.7%）p27^kip1高表达，其中成熟性畸胎瘤5例，生殖细胞瘤10例，胚胎性癌和混合性生殖细胞瘤各1例；11例（39.3%）p27^kip1低表达，其中生殖细胞瘤8例，未成熟性畸胎瘤、混合性生殖细胞瘤、绒毛膜癌各1例。13例（46.4%）Ki-67LI>50%，9例（32.1%）Ki-67LI为25%～50%，6例（21.4%）Ki-67LI<25%。原发性CNSGCTs组织中p27^kip1表达和Ki-67LI与肿瘤的组织学类型有关，p27^kip1表达水平与患者性别、年龄，肿瘤大小、部位，预后和复发以及Ki-67LI均无相关性(P>0.05)。结论 p27^kip1在恶性程度较高的原发性CNSGCTs中呈现低表达，提示其可能通过下调细胞周期G1→S的调控点而参与生殖细胞肿瘤的发生和发展。

Objective To investigate the clinicopathological significance of expressions of tumor suppressor gene p27kip1 and expression of cyclin Ki-67 in primary central nervous system germ cell tumors (CNSGCTs). Methods The expressions of p27kip1 and Ki-67 in tissues of 28 cases of primary CNSGCTs were detected by immunohistochemical method and Ki-67 labeling index (Ki-67 LI) was calculated. Results Among 28 cases of primary CNSGCTs, the p27kip1 expression of 17 cases (60.7%) was high, including 5 cases of mature teratomas, 10 cases of germinomas, 1 case of embryonal carcinoma, and 1 case of mixed GCT; and the p27kip1 expression of 11 cases (39.3%) was low, including 8 cases of germinomas, 1 case of immature teratoma, 1 case of choriocarcinoma, and 1 case of mixed GCT. The Ki-67 LI of 13 cases (46.4％) was higher than 50%; Ki-67 LI of 9 cases (32.1%) was 25%-50%; and Ki-67 LI of 6 cases (21.4%) was lower than 25%. The expression of p27kip1 and Ki-67 LI correlated with the histological types of CNSGCTs. The expression of p27kip1 did not correlate with sex, age, size of tumor, location, recurrence, prognosis, or Ki-67 LI (P>0.05). Conclusion The expression of p27kip1 is low in malignant primary CNSGCTs, which suggests that p27kip1 may involve in the formation and development of germ cell tumor by down-regulating the control point for transiting from G1 to S phase.