It is demonstrated that protein arginine methyltransferase 6 (PRMT6), poly(ADP‐ribose) polymerase 1 (PARP1), and the cullin 4 B (CUL4B)‐Ring E3 ligase (CRL4B) complex interact to form a transcription‐repressive complex that co‐occupies the core clock gene PER3 promoter, promoting the proliferation and metastasis of breast cancer by interfering with circadian rhythm oscillation. The gene discussed is PER3; the disease is breast cancer.