PTEN，表皮生长因子受体和Ki-67在胸腺瘤中的表达及其临床意义

目的探讨张力蛋白同源、10号染色体缺失的磷酸酶基因（phosphatase and tensin homolog deleted on chromosome ten，PTEN）、表皮生长因子受体（epidermal growth factor receptor，EGFR）及增殖性核抗原Ki-67在人胸腺瘤发生、浸润和转移中表达的生物学意义及其相互关系。方法采用免疫组织化学SP法，检测45例胸腺瘤患者中PTEN、EGFR和Ki-67的表达，用5例先天性心脏病手术患者的正常胸腺组织作对照。结果5例正常胸腺组织中，PTEN全部为阳性表达，EGFR仅微量阳性表达，Ki-67无1例阳性表达。45例胸腺瘤组织中，从良性胸腺瘤、侵袭性胸腺瘤到胸腺癌，PTEN阳性表达率逐渐下降，差异有统计学意义（x^2=7．808，P=0．020）；EGFR、Ki-67表达率逐渐增高，差异有统计学意义（x^2=8．032，0．018，7．006，P=0．030）；PTEN、EGFR和Ki-67的阳性表达率与胸腺瘤的肿瘤性质、Masaoka分期及淋巴结转移等参数有关（P〈0．05）；PTEN与EGFR、Ki-67的表达呈负相关（r=0．632，-0．653；P〈O．01），EGFR与Ki-67的表达呈正相关（r-0．807，P〈O．01）。结论胸腺瘤的发病分子机制中存在多种基因变异，PTEN的失表达和EGFR、Ki-67的过度表达在其发生、浸润和转移中起一定的作用；PTEN、EGFR和Ki-67的异常表达密切相关，共同影响着胸腺瘤的发生、发展，三者的检测有助于对胸腺瘤的早期诊断，并判断其恶性程度、侵袭和转移能力及预后。

Expression and Clinical Significance of Phosphatase and Tensin Homoiogue Deleted on Chromosome Ten,Epidermal Growth Factor Receptor and Ki-67 in Human Thymic Tumors

Objective To investigate the expression and correlation of phosphatase and tensin homologue deleted on chromosome ten（PTEN）, epidermal growth factor receptor（EGFR） and Ki-67 in human thymic tumors, and their possible role in tumor genesis, infiltration and metastasis. Methods The expression of PTEN, EGFR and Ki 67 were detected by using SP immunohistochemical technique in 45 cases of thymic tumors and 5 cases of normal thymic tissues. Results In 5 cases of normal thymic tissues, the expression of PTEN was strongly positive, whereas EGFR and Ki-67 were weakly positive or negative. In 45 cases of thymic tumors, the positive ratio of PTEN were significantly reduced from benign thymoma, invasive thymoma to thymic carcinoma （X2- 7. 808, P= 0. 020）, but the positive ratio of EGFR and Ki-67 were gradually increased（X2=8. 032, 0. 018, 7. 006; P=0. 030）. The positive ratio of PTEN, EGFR and Ki-67 protein were significantly related to Levine classification, Masaoka staging and lymph node metastasis （P%0.05）. PTEN positive cases were negatively correlated with EGFR and Ki-67 （r=--0. 632,--0. 653;P~0.01）, EGFR positive cases were positively correlated with Ki-67 in thymic tumors（r= 0. 807,P〈0. 01）. Conclusions Reduced or absent PTEN and increased EGFR and Ki-67 expression might play an important role in the genesis, invasiveness and metastasis of thymic tumors. The expression of PTEN is strongly associated with the expression of abnormal EGFR and Ki-67. Detection of the three protein expressions simultaneously might be more helpful in making an early diagnosis of the tumors jndgement of theirs malignant degree ,invasiveness and metastasis capacity, as well as the prognosis.