HIF1A and breast cancer: Most strikingly, in our multivariate analysis, which was also employed to evaluate the clinical impact of HIF-1α/ PGC-1α plasma level on prognosis, PGC-1α plasma level was an independent prognostic factor for disease free survival in breast cancer patients (HR=1.582, 95.0% CI 0.951~2.633, P < 0.1).