Hypoxia-inducible factor 1 alpha in high-risk breast cancer: an independent prognostic parameter?

BACKGROUND: Hypoxia-inducible factor 1 alpha (hif-1alpha) furnishes tumor cells with the means of adapting to stress parameters like tumor hypoxia and promotes critical steps in tumor progression and aggressiveness. We investigated the role of hif-1alpha expression in patients with node-positive breast cancer.

METHODS: Tumor samples from 77 patients were available for immunohistochemistry. The impact of hif-1alpha immunoreactivity on survival endpoints was determined by univariate and multivariate analyses, and correlations to clinicopathological characteristics were determined by cross-tabulations.

RESULTS: hif-1alpha was expressed in 56% (n = 43/77) of the patients. Its expression correlated with progesterone receptor negativity (P = 0.002). The Kaplan-Meier curves revealed significantly shorter distant metastasis-free survival (DMFS) (P = 0.04, log-rank) and disease-free survival (DFS) (P = 0.04, log-rank) in patients with increased hif-1alpha expression. The difference in overall survival (OS) did not attain statistical significance (5-year OS, 66% without hif-1alpha expression and 55% with hif-1alpha expression; P = 0.21). The multivariate analysis failed to reveal an independent prognostic value for hif-1alpha expression in the whole patient group. The only significant parameter for all endpoints was the T stage (T3/T4 versus T1/T2: DMFS, relative risk = 3.16, P = 0.01; DFS, relative risk = 2.57, P = 0.03; OS, relative risk = 3.03, P = 0.03). Restricting the univariate and multivariate analyses to T1/T2 tumors, hif-1alpha expression was a significant parameter for DFS and DMFS.

CONCLUSIONS: hif-1alpha is expressed in the majority of patients with node-positive breast cancer. It can serve as a prognostic marker for an unfavorable outcome in those with T1/T2 tumors and positive axillary lymph nodes.