EXPRESSION OF CELL REGULATORY PROTEINS IN OVARIAN BORDERLINE TUMORS

BACKGROUND. Tumors of borderline malignancy are still a controversial subgroup of ovarian neoplasms. The expression of several cell regulato ry proteins was studied to characterize the molecular phenotype of the se tumors, and to compare them with their benign and malignant counter parts. METHODS. Specimens from 22 patients with tumors of borderline m alignancy (11 serous and 11 mucinous tumors), 12 patients dth benign t umors, and 16 patients with invasive ovarian carcinomas were evaluated for expression of epidermal growth factor receptor (EGFR), HER-2/neu, PTP1B, and p53 by immunohistochemical techniques. RESULTS. One or bot h of the tyrosine kinase growth factor receptors EGFR and HER-2/neu wa s expressed by 42% of benign, 59% of borderline, and 81% of malignant ovarian tumors. EGFR was expressed in a significantly greater fraction of malignant lesions (69%) than borderline lesions (18%) (P < 0.004). EGFR expression was not observed among the 11 mucinous borderline tum ors. HER-2/neu was expressed by 50% of borderline tumors and was not a marker for malignancy. The tyrosine phosphatase PTP1B was expressed b y a similar fraction of benign (17%), borderline (27%), and malignant (19%) tumors. The number of cases studied precluded correlation of kin ase and phosphatase activity. However, among 12 tumors with PTP1B expr ession, 9 also expressed EGFR or HER-2/neu. Overexpression of p53 was observed only in malignant serous tumors and was not found in malignan t mucinous, borderline, or benign lesions. CONCLUSIONS. Either EGFR or HER-2/neu was detected in a majority of borderline cancers. PTP1B was present only in a minority of these cancers. Frankly malignant serous lesions differed from borderline and benign tumors with regard to exp ression of EGFR and overexpression of p53. (C) 1996 American Cancer So ciety.