Pten, P27 And Ki-67 Expression In Thymoma And Clinical Significance

Objective:To study the expression of PTEN, p27and Ki-67 in thymoma and to explore the correlation between the expression of the factors and the thymoma status, including pathological types, clinical stage and differentiation, MG combine and prognosis .Methods:Surgically resected and pathologically proved cases of thynoma were collected. These patients have been followed up for 5 years by questionnaire and phone calls.All of clinical and follow-up information were included in the study, and all the patients received neither radiocherapy nor chemocherapy before the surgery. Information related to patient's histological type, pathological stage and surive time were recorded. The expression of PTEN, p27 and Ki-67 were detected by immunohistochemistry SP method. All the results were statistically analyzed with SPSS 13.0 software package.Results:In 12 cases of normal thymic tissues, the expression of PTEN, p27 was strongly positive, where Ki-67 were weakly positive or negative. In 52 cases of thymic tumors, the positive ratio of PTEN were significantly reduced from benign thymoma, invasive thymoma to thymic carcinoma(χ2=8.54, P<0.05), the positive ratio of p27 were significantly reduced also(χ2=16.46, P<0.01), but the positive ratio of Ki-67 were gradually increased(χ2=13.95, P<0.01). The positive ratio of PTEN, p27 and Ki-67 protein were significantly related to Levine classification, Masaoka staging and lymph node metastasis (P<0.05). The expression of PTEN and p27, Ki-67 wasn't different in Bernatz histological classification and with/without MG(P>0.05). Ki-67 positive cases were negatively correlated with PTEN and p27(r=-0.761, -0.576; P<0.01). PTEN positive cases were positively correlated with p27 in thymic tumors(r=0.758, P<0.01).ConclusionThe absence of PTEN and p27 in human thymic tumors is closely related to malignant degree, Masaoka stage and prognosis. Therefore, it can be used to evaluate the progress of tumor. The over-expression of Ki-67 in human thymic tumors is obviously associated with the differentiation degree of the tumor, which can be referred to as an important index reflecting the malignant degree and progress of tumor. The protein expression of PTEN,p27 and Ki-67 does not have any relationship with whether the thymic tumor combined with MG and Bernatz histological classification. The joint detection of the three protein expressions plays a significant importance in the early diagnosis of the human thymic tumors, the judgment of their malignant degree, invasiveness and metastasis capacity as well as the prognosis.