Immunohistochemical detection of p185 product, p21 product, and proliferating cell nuclear antigen (PCNA) in formalin-fixed, paraffin-embedded tissues from ovarian carcinomas. Preliminary data.

Immunohistochemical techniques for the detection of oncogene products and the assessment of cell kinetics can represent promising investigational tools in clinical oncology. In the present paper the immunohistochemical expression of p185, p21 and proliferating cell nuclear antigen (PCNA) was retrospectively assessed in formalin-fixed, paraffin-embedded tissue samples taken from 28 primary ovarian carcinomas at first surgery. Positive immunostaining for p185 was found in 0% of 6 Stage I and 23% of 22 Stage III-IV tumors. Positive immunostaining for p21 was observed in 0% of early and 41% of advanced carcinomas; this immunohistochemical finding correlated significantly with histologic grade (G3 vs G1-2 = 47% vs 9%, p = 0.042). Elevated PCNA immunoreactivity was detected in 33% of Stage I and 50% of Stage III-IV tumors. Among the 20 patients with advanced carcinoma who underwent cisplatin or carboplatin based chemotherapy followed by second-look laparotomy, the pathologic complete response (pCR) rate was 36% for patients with low PCNA expression and 0% for those with elevated PCNA expression. A tendency towards a higher pCR rate was also found for patients with negative immunostaining for p185 or for p21. The prognostic value of the immunohistochemical detection of p185, p21, and PCNA in ovarian carcinoma deserves to be further investigated.