IMMUNOHISTOCHEMICAL STUDY OF TYPE-I COLLAGEN AND TYPE-I PN-COLLAGEN IN BENIGN AND MALIGNANT OVARIAN NEOPLASMS

Background. Type I collagen is a major constituent of the interstitial connective tissue. Although ovarian carcinoma is known to induce the expression of type I collagen in the peritoneal cavity, the distributi on and metabolic activity of this collagen in ovarian tumor tissue are not known. Methods. The distributions and staining intensities of dif ferent molecular forms of type I collagen in ovarian neoplasms were st udied immunohistochemically with antibodies to the aminoterminal prope ptide of type I procollagen (PINP) and the cross-linked carboxytermina l telopeptide of type I collagen (ICTP), reflecting the presence of ne wly synthesized and old, cross-linked type I collagen,respectively. Re sults. A regular pattern of moderately staining, relatively uniform fi bers was observed in the stroma of benign serous and mucinous cystaden omas, indicating limited participation in tumor growth. The staining w as accentuated subepithelially in borderline epithelial neoplasms and in well differentiated cystadenocarcinomas, suggesting induction of th e stromal collagen synthesis by the tumor cells. Fewer degraded collag en fibers were found in moderately differentiated carcinomas, most lik ely because of enzymatic degradation of the stroma surrounding the neo plasms during tumor spread. Strongly staining, irregular collagen fibe rs occurred closely around islets of tumor cells in undifferentiated m alignant neoplasms and in metastases of ovarian carcinomas; also, intr acellular staining was present in part of the malignant cells. In most cases, the staining reactions obtained with the two different antibod ies were similar, probably indicating rapid processing of the newly sy nthesized type I collagen (indicated by PINP) to a maturely cross-link ed form (indicated by ICTP). Conclusions. Synthetic and degradative pr ocesses are typical of the collagenous matrix in malignant ovarian tum ors. Aberrant expression of type I collagen may occur in anaplastic ov arian carcinomas.