In the exploration cohort, FFAR4 was demonstrated as an independent prognostic factor for recurrences (HR: 2.183, 95% CI: 1.360–3.504, P = 0.001) and breast cancer-specific deaths (HR: 2.102, 95% CI: 1.173–3.766, P = 0.013) in HRPBC cases. This evidence concerns the gene FFAR4 and breast cancer.