Expression of αvβ3 integrin is less frequent in ovarian epithelial tumors of low malignant potential in contrast to ovarian carcinomas

Abstract

Ovarian tumors of low malignant potential (LMPs) histologically lack invasion and have excellent prognosis in contrast to invasive carcinomas. Integrins are heterodimeric adhesion molecules thought to play a role in cell migration and tumor progression. The α v β 3 integrin in particular mediates melanoma invasion in vitro and promotes neoplastic angiogenesis, facilitating breast cancer metastasis. In addition, α v β 3 expression has been detected in ovarian cancer cell lines and in a limited number of human ovarian cancer samples. The distribution pattern of this integrin in LMPs is not known. We examined tissue sections from 19 LMPs and 31 ovarian carcinomas for α v β 3 in addition to α 5 β 1 and α 2 β 1 integrins, which have been shown to be expressed in ovarian cancer cell lines. Variable immunoreactivities of α 5 β 1 and α 2 β 1 were detected in both LMPs and ovarian carcinomas. Most (74.2%) ovarian carcinomas were α v β 3 positive, whereas only 36.8% of LMPs were positive, which is statistically significant ( P = .009). These results establish the distribution pattern of α 2 β 1, α 5 β 1, and α v β 3 integrins in LMPs. The biological significance of the less frequent expression of α v β 3 in LMPs compared with carcinomas of the ovary needs further elucidation.