Objective: To evaluate the two-tier system for the grading of ovarian serous carcinomas, and to analyze Pax2, p53, Ki-67 protein expression and their prognostic values for low- and high-grade ovarian serous carcinomas.
Methods: A total of 38 cases of low-grade and 100 cases of high-grade ovarian serous carcinomas were selected based on the two-tier grading system. Immunohistochemistry was used to detect Pax2, p53 and Ki-67 protein expression in all cases. Correlation of the two-tier system with immunohistochemical results and prognostic parameters were performed.
Results: (1) The overall survival, disease-free survival and 5-year survival rates were significantly higher in the low-grade serous carcinoma cases than in the high-grade cases (P < 0.05). (2) Significant differences in protein expressions were found between the low- and high-grade serous carcinomas. The high-grade serous carcinomas had a significantly higher expression level of p53 (55.0% vs 13.2%, P < 0.05) and Ki-67 (42.1% vs 13.7%, P < 0.05), while low-grade carcinomas had a significantly higher expression level of Pax2 (65.8% vs 13.0%, P < 0.05). (3) Pax2 positive cases had a significantly better overall survival and 5-year survival rates than Pax2 negative cases (P < 0.05). The expressions of p53 and Ki-67 were found to have little correlation with overall survival and disease-free survival (P > 0.05).
Conclusions: The two-tier system for the grading of ovarian serous carcinomas has a good prognostic value. There are significantly differences in expressions of Pax2, p53 and Ki-67 between low- and high-grade ovarian serous carcinomas. Compared with p53 and Ki-67, Pax2 is likely a better prognostic indicator for ovarian serous carcinoma.