Oncogene expression in ovarian cancer: a pilot study of c-myc oncoprotein in serous papillary ovarian cancer.

The nuclear-associated protein product of the c-myc gene, p62c-myc, was assayed simultaneously with total DNA using flow cytometry in nuclei extracted from archival biopsies of serous papillary carcinoma of the ovary. The oncoprotein was probed with a synthetic peptide-induced mouse monoclonal antibody which was subsequently labeled with a fluorescent rabbit anti-mouse immunoglobulin and DNA was assayed using the nucleic acid fluorochrome propidium iodide. Serous papillary ovarian carcinoma expressed significantly higher p62c-myc levels compared with normal ovary (P less than 0.00003 Mann-Whitney U test). Biopsies classified as "borderline" low-potential malignancy exhibited levels between normal ovary and carcinoma. The difference between normal and "borderline" was significant at P less than 0.003, but no difference between "borderline" and frankly invasive biopsies was observed, P = 0.149. There was no difference among the histological grades of carcinomas. All normal ovaries had diploid DNA content as did 5/6 cases of "borderline" malignancy. The majority of cases of carcinoma, 28/36, were aneuploid. There was a statistically significant difference in the distribution of aneuploidy, P less than 0.005, between invasive carcinomas and those classified as "borderline" low-potential malignancy.