• Open Access

Prognostic significance of tumor/stromal caveolin-1 expression in breast cancer patients

Authors


To whom correspondence should be addressed.
E-mail: toi@kuhp.kyoto-u.ac.jp

Abstract

Caveolin-1 (Cav-1) has been extensively characterized in cancer biological research. However, the role of Cav-1 in the interaction between tumor and stromal cells remains unclear. In the present study, we examined Cav-1 expression in tumor cells and stromal cells in breast cancer tissue by immunohistochemical analysis and evaluated its prognostic value in a training cohort. Immunohistochemical analysis of Cav-1 expression was scored as (++), (+) or (−) according to the proportion of positively stained tumor cells (T) and stromal cells (S). Correlation analysis between tumor/stromal Cav-1 expression and clinicopathological parameters revealed that only T(++) Cav-1 status was positively associated with tumor size and histological nodal status (= 0.019 and 0.021, respectively). Univariate analysis revealed that combined T(++)/S(−) status was significantly correlated with unfavorable prognostic outcomes (< 0.001). Multivariate analysis demonstrated that this combined status is an independent prognostic factor for primary breast cancer (= 0.002). Clinical outcomes in different subgroups of breast cancer patients were also strictly dependent on this combined status (< 0.05). The prognostic value of T(++)/S(−) Cav-1 status was also validated in the testing cohort. Collectively, our data indicate that high Cav-1 expression in tumor cells and lack of this expression in stromal cells could help identify a particular subgroup of breast cancer patients with potentially poor survival. Further studies are required to understand the regulatory mechanism of Cav-1 in the tumor microenvironment. (Cancer Sci 2011; 102: 1590–1596)

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