The association between Axl and vimentin protein expression has been observed in several cell lines. However, the clinical importance of Axl and vimentin expression in breast cancer have not been fully determined.

The expressions of Axl and vimentin were evaluated by immunohistochemistry in a total of 343 patients with invasive ductal carcinoma. The relationships between expression of Axl and vimentin and clinicopathologic characteristics and prognosis were analyzed.

Axl expression was classified into high (n = 170) and low (n = 173) expression groups. Axl expression alone was not associated with any clinicopathologic factor or prognosis. Coexistence of vimentin-positive and Axl-high expression was observed in 10.5% (n = 36). Vimentin-positive and Axl-high tumors were associated with triple-negative breast cancers (P = .0396) and with poor prognosis in terms of both recurrence-free survival (P = .0126) and overall survival (P = .0005) compared to the other groups, including vimentin-positive and Axl-low tumors, vimentin-negative and Axl-high tumors, and vimentin-negative and Axl-low tumors. Multivariate analysis showed that coexistence of vimentin-positive and Axl-high expression was an independent poor prognostic factor for recurrence-free survival (hazard ratio, 2.78; 95% confidence interval, 1.23-5.68; P = .0158) and overall survival (hazard ratio, 3.72; 95% confidence interval, 1.51-8.47; P = .0059).

Coexistence of vimentin-positive and Axl-high expression is a poor prognostic factor for primary breast cancer. Vimentin and Axl expression might contribute to the aggressive phenotype in breast cancer.