乳腺癌组织P16基因异常表达及意义

Objective To evaluate the relationship between the aberrant expression of P16 and the clinic-pathological features in breast cancer. Methods 72 cases of breast cancer were collected and the expression of P16, Her-2, ER, PR, P53, Ki-67 was measured by immunohistochemistry. Their correlations with the clinic-pathological features（menstruation, tumor size, histological grade, lymph node metastasis were statistically analyzed. Results Abnormal expression of P16 was detected in 36.1%（26/72 case）of breast cancers. The staining of P16 was not only increased，but also the subcellular distribution was changed from nuclear to cytoplasmic or whole cell staining. In general, the individual cell staining (1+) usually presented nuclear, while as increasing expression, P16 showed mainly in cytoplasmic or whole cells( 3+) even diffusing in extracellular, and the moderate staining was multi-focal both in nuclear and cytoplasmic. The expression of P16 was significantly increased in ER negative group compared with ER positive group (78.6% vs 9.1%)(p<0.001). Statistical analysis showed a significant correlation of high Ki67 index with the group of P16 positive (U=314.500, Degree freedom=2, p=0.003). In addition, significant difference was calculated between pre- and post- menopause (55.6% vs 24.4%, p=0.008）and P16 expression were also more credited to the poor-differentiated group in histological grading: 11.8% for high differentiated, 27.6% for moderated and 61.5% for poor group, respectively(p=0.002). Conclusions The aberrant expression of P16 in breast cancers correlated closely with loss of estrogen receptor, high proliferation index or high histologic grade, predisposed to the patients of premenopause, implicating that the abnormal expression of P16 should be a predictor of poor response to endocrine therapy or more aggressive behavior.