Through gain and loss of function and rescue experiments, we confirm that MIR200CHG regulates the expression of tumor-associated proteins CDKN2A, cyclin D1, cyclin E1, BCL2, BAX, MMP1, MMP2, and MRP1 by binding YB-1, thereby promoting breast cancer proliferation, invasion, and resistance. The gene discussed is CCND1; the disease is breast cancer.