Extent of apoptosis in ovarian serous carcinoma: relation to mitotic and proliferative indices, p53 expression, and survival.

AIMS To assess the extent of apoptosis in ovarian serous carcinoma and to examine possible relations between apoptosis, cell proliferation, p53 overexpression, and patient survival. METHODS Apoptotic and mitotic indices were obtained by examining haematoxylin and eosin stained sections from 30 patients with ovarian serous carcinoma. Apoptosis was also evaluated semiquantitatively by in situ end labelling of fragmented DNA. Expression of p53 and determination of Ki-67 labelling indices were based on immunohistochemical staining. Clinical details were obtained from patients' clinical records. For statistical analysis, Fisher's exact test, parametric (Pearson) linear correlations, and the Kaplan-Meier method were used. RESULTS The mean apoptotic index was 1.3% (range 0.02-3.9%), the mean mitotic index was 0.4% (range 0.02-1.1%), and the mean Ki-67 labelling index was 16% (range 4-32%). There were significant correlations between the apoptotic and mitotic indices (p < 0.0205) and between the mitotic and Ki-67 labelling indices (p < 0.024). There was a significant correlation between a high apoptotic index and poor prognosis (p < 0.02). p53 was overexpressed in 16 cases but the extent of apoptosis and outcome were both independent of p53 status. CONCLUSIONS These results suggest that regulation of apoptosis is an integral component of tumour cell kinetics in ovarian serous carcinoma, and that increased apoptosis is indicative of aggressive tumour growth. p53 expression did not correlate with altered apoptosis, but the possibility of an attenuated apoptotic response to subsequent DNA damage by anticancer agents is not excluded.