The correlation analysis between C14orf166 expression and clinicopathological characteristics suggested C14orf166 expression was significantly correlated with clinical stages, T classification, N classification and PR expression, Kaplan–Meier curves with log rank tests showed patients with low C14orf166 expression had better survival, Cox-regression analysis suggested C14orf166 was an unfavorable prognostic factor for breast cancer patients. The gene discussed is RTRAF; the disease is breast cancer.