Expression Of P16 And Cyclin D1 Protein, DNA Ploidy Analysis In Renal Cell Carcinoma And It's Clinical Significance

Objective: Inactivation of tumor suppressor genes on chromosome 9p is considered a critical event in renal cell carcinoma pathogenesis. Alterations of CDKN2A on 9p21 have been reported in renal cancer cell lines, but their relevance for primary renal carcinomas is unclear. Fluorescence in situ hybridization analysis of 54 RCCs revealed homozygous CDKN2A deletions indicating that this mechanism of CDKN2A inactivation is not rare in RCC. Immunohistochemical CDKN2A expression was absent in normal renal tissue and was only detected in six of 382 RCCs (1.5%) on a renal tumor microarray. These data suggest that CDKN2A alterations are present in RCCs and a second, yet unknown tumor suppressor gene proximal to the CDKN2A locus, may play a role in RCC development.In addition, Cyclins D1 were not expressed in normal renal tissue. Low protein contents of cyclin D1 were associated with high nuclear grade, large tumour size, and poor prognosis for patients with conventional tumours,but in some research Cyclin D1 expression in RCC did not correlate with survival.However, very little is known about aberrations in the G1-S transition in human renal-cell carcinoma (RCC). In this study, the expression of P16, Cyclin D1 protein and DNA ploidy in RCC tisssues were detected by flow cytometry (FCM) to study their relations and the relation to the development and the biological characteristics of RCC. Methods: Fresh samples of 68 renal cell carcinoma (49 men and 19 women, mean age 55.4 years, range from 33 to 79 years) and 60 corresponding paratumor tissues (43 men and 17 women, mean age 57 years, range from 33 to 79 years) were obtained from patients with RCC who underwent radical nephrectomy at the Fourth Hospital of Hebei Medical Univercity between 2002 and 2004. Meanwhile 8 normal renal tissues were used as control. Cell type of RCC: clear cell type 40 cases, granular cell type 3 cases, mixed-cell type 20 cases, sarcomatoid type 5 cases. According to Robson staging : stage Ⅰ13 cases, stage Ⅱ40 cases, stage Ⅲ7 cases, stage Ⅳ8 cases. According to Fuhrman grading:gradeⅠ~Ⅱ48 cases, grade Ⅲ20 cases. Single cell suspensions were made and labeled with fluorescence by indirect immunofluorescence technique and studied by FCM, the results were anlysised by computer. Fluorescence Index (FI) was defined as the quantitative expression index of P16 and Cyclin D1 protein, the FI value more than 1.0 should be considered positive expression, whereas negative expression. DNA ploidy levels was expressed by DNA Index (DI), the DI value within 1.00±0.16 should be considered DNA diploid, whereas DNA aneuploid. Results: 1 The expression of P16 protein in renal cellcarcinoma and corresponding paratumor tissues.In the tissues of renal cell carcinoma, the positive expression rate of P16 protein was 26.5% in renal cell carcinoma and 60% in corresponding paratumor tissues, the difference was statistically significant (p<0.05). Quantitative expressing rate of P16 protein in tumors sized larger than 50 mm (17.5%), Robson Ⅲ-Ⅳstaging (7.1%), Fuhrman gradeⅢ(7.1%) were significantly lower than those in tumors sized less than 50 mm (35.7%), RobsonⅠ-Ⅱstaging (29.6%), Fuhrman gradeⅠ~ Ⅱ(37.5%), it has remarkable difference in statistics (P<0.05). The expression positive rate of P16 protein was 11.5% in the RCC with clinical sympotom,and 33.3% in the RCC without clinical sympotom, the difference was statistically significant (p<0.05). The expression positive rate of P16 protein was7.1% in the RCC invaded around tissues,and 29.6% in the RCC without invading around tissues, the difference was statistically significant (p<0.01).2 The expression of Cyclin D1 protein in renal cell carcinoma and corresponding paratumor tissues.In the tissues of renal cell carcinoma, the positive expression rate of Cyclin D1 protein was 79.4% in renal cell carcinoma and 46.7% in corresponding paratumor tissues, the difference was statistically significant (p<0.01). Quantitative expressing rate of Cyclin D1 protein in Robson Ⅲ~Ⅳstaging (92.7%)were significantly higher than those in...