Expression and significance of a new tumor suppression gene PTEN in primary renal cell carcinoma.

BACKGROUND & OBJECTIVE: PTEN gene is a newly discovered tumor suppressor gene, that maps to chromosome 10q23, and of longstanding interest to those studying somatic mutations in human tumors. Mutation and deletion of PTEN gene probably resulted in a new signal transduction pathway related to human malignant tumors. It was reported that PTEN gene mutated and deleted in renal cell carcinoma, however, there was no report concerning its expression in renal cell carcinoma. This study was designed to investigate expression and significance of PTEN gene in primary renal cell carcinoma. METHODS: Immunohistochemical peroxidase-conjugated streptavidin (SP) method was used to detect expression of PTEN gene in 40 cases of primary renal cell carcinoma, 18 with renal tissues closely adjacent to carcinoma and 5 case of normal renal tissues. The relationship between expression of tumor suppressor gene of PTEN and the percentage of lymph node metastasis of renal cell carcinoma was analyzed. RESULT: It was showed that PTEN gene was expressed in all 5 case of normal renal tissues and 18 cases of renal tissues closely adjacent to carcinoma. The intensity was relatively strong and it was localized mainly in cytoplasm of epithelium cells of renal tubular. Expression of PTEN in 40 cases of renal cell carcinoma were different, 12.5% were negative, 17.5% were weak positive, and 70% were strong positive. PTEN protein was localized in cytoplasm of carcinoma cells. The percentage of lymph node metastasis of renal cell carcinoma negative or weak positive of PTEN protein was 80% and 51.74%, respectively. The percentage of lymph node metastasis of renal cell carcinoma positive of PTEN protein was 10.71%, comparing with those of renal cell carcinoma negative or weak positive of PTEN protein, the difference was significant (P < 0.05). CONCLUSION: This study suggested that PTEN gene was deleted or weakly expressed in primary renal significant cell carcinoma, which is probably related to tumorigenesis and development of renal cell carcinoma.