OBJECTIVETo evaluate the two-tier MDACC grading system for ovarian serous carcinoma by comparing with the WHO grading system, and to investigate the role of p53 immunostaining in ovarian serous carcinoma grading.

METHODS72 cases ovarian serous carcinoma of ovary were graded basing on the MDACC and WHO grading systems, respectively. Statistic analyses were made for the relationship between the data obtained from two grading systems and their clinical significance. All the cases were examined immunohistochemically by using antibody against p53 protein and the immunohistochemistry findings were analyzed with the two grading systems and clinical parameters.

RESULTSThere was a good correlation between the MDACC and WHO grading system (r=0.543, P=0.000). Neither system has a definite relationship with the disease-free survival time (P=0.170 vs. P=0.075), cytoreduction (P=0.478 vs. P=0.120), and the curative effect of platinum-based chemotherapy (P=0.418 vs. P=0.403). However, compared with the WHO grading system, MDACC grading system has a better correlation with tumor stage (P=0.041 vs. P=0.002), 3-year disease-free survival rate (P=0.077 vs. P=0.004), overall survival time (P=0.080 vs. P=0.046), and p53 immunohistochemistry results (P=0.334 vs. P=0.035). No significant difference was found between p53 immunohistochemistry results with other clinical characteristics and prognostic factors.

CONCLUSIONSCompared with the WHO system, the MDACC system showed a better prognostic value and was more likely correlated with the novel dualistic model for ovarian serous carcinogenesis. Although p53 immunostaining was valuable in assisting MDACC grading, it should be cautious to use it alone as an independent indicator in predicting the prognosis of ovarian serous carcinoma.