Overexpression of c-Abl predicts unfavorable outcome in epithelial ovarian cancer

Abelson tyrosine kinase (c-Abl) has been shown to promote solid tumor invasion and metastasis. However, little is known regarding whether c-Abl contributes to the development or progression of epithelial ovarian cancer (EOC). The aims of this study are to determine the expression of c-Abl and investigate a possible relationship between c-Abl and prognosis in EOC.

c-Abl protein level was evaluated in 137 EOC specimens by immunohistochemical staining and 32 EOC specimens by Western blot analysis. Expression of c-Abl in ovarian cancer cell lines was measured by Western blot analysis and immunofluorescence. Survival analysis was performed to assess the correlation between c-Abl expression and survival.

Immunohistochemical staining and Western blot analysis revealed that c-Abl was overexpressed in EOC compared with samples from a non-invasive ovarian tumor and normal ovaries (P<0.05). Furthermore, expression of c-Abl was significantly associated with advanced FIGO stage, poor grade, serum Ca-125 and residual tumor size (P<0.05). By Western blot analysis, c-Abl expression was examined in four ovarian cancer cell lines. Meanwhile, immunofluorescence was performed to show c-Abl expression in SKOV3 and 3AO cell lines. Survival analysis demonstrated that patients with low c-Abl staining had a significantly better survival compared to patients with high c-Abl staining (P<0.05). In multivariate analysis, c-Abl overexpression, poor grade, advanced stage and suboptimal surgical debulking were independent prognostic factors of poor survival.

Our present study finds that c-Abl overexpression is associated with an unfavorable outcome. c-Abl may be a crucial predictor for EOC metastasis.