Vav3 oncogene is upregulated and a poor prognostic factor in breast cancer patients

The Vav3 oncogene is overexpressed and has a significant role in the tumorigenesis of prostate cancer and glioblastoma. In the present study, the expression status and prognostic value of Vav3 expression was investigated in breast cancer. Vav3 protein levels were analyzed by immunoblotting in human breast cancer and epithelial cell lines. Immunohistochemistry was used to detect Vav3 in a tissue microarray of 173 breast cancers and 19 benign breast lesions. Statistical analysis was performed to reveal the association between Vav3 expression and clinicopathological parameters. Disease-free survival (DFS) and overall survival (OS) were calculated by Kaplan-Meier analysis and the Cox regression model. The Vav3 protein level was higher in the breast cancer cell lines than in the normal human breast cells. Vav3 was expressed in 86.1% of breast cancer patients, but in only 15.6% patients with benign breast disease. Patients with negative estrogen receptor expression, axillary lymph node involvement and a high tumor-node-metastasis stage demonstrated a higher positive rate of Vav3 expression. The Kaplan-Meier survival analysis revealed that patients with higher Vav3 expression exhibited shorter DFS and OS times. The multivariate Cox analysis revealed that Vav3 was a prognostic factor of survival. Overall, Vav3 was overexpressed in human breast cancer cells and this correlated with a shorter survival time, indicating that Vav3 is a biomarker of a poor prognosis for breast cancer patients.