Overexpression of focal adhesion kinase, a protein tyrosine kinase, in ovarian carcinoma.

Abstract

Focal adhesion kinase (FAK) is a tyrosine kinase that is important to such key functions such as cell adhesion, motility, and invasion. A MEDLINE search of the years 1980-1998 found no previous reports of FAK expression in human ovarian carcinoma. The authors performed experiments to determine whether FAK expression is elevated in this disease. Ten normal human ovarian tissue samples and 26 cancer samples from patients with Stage I-IV ovarian carcinoma were obtained. Two ovarian carcinoma cell lines were also analyzed. FAK expression was determined by Western blot analysis with the V39 anti-human FAK polyclonal antibody. The level of FAK protein expression was determined using densitometric scanning of the 125 kD band on autoradiographs of Western immunoblots. Serous cancers expressed fourfold-increased values of FAK relative to normal ovarian tissue (P < 0.0001), and nonserous adenocarcinomas expressed threefold- to fourfold-increased values of FAK (P < 0. 0006). Ovarian carcinoma cell lines also expressed increased values of FAK. With a cutoff of 40, an elevated FAK level was associated with a sensitivity of 93% and specificity of 100%. There was no significant difference in FAK expression with regard to grade or stage of tumor. FAK is significantly overexpressed in ovarian carcinoma, implying that FAK may play an important role in ovarian carcinogenesis. FAK expression may be useful as a screening tool to identify newly developed disease or as a tumor marker in confirmed cases of epithelial ovarian carcinoma. FAK may also serve as a potential target for therapeutic disruption of ovarian carcinoma progression.