In addition, elevated expression of ZEB1 and total USP51 protein was demonstrated to be correlated with poor overall survival rates in the same cohort (Supplementary Fig. S7), which is consistent with the notion that ectopic USP51 contributes to the malignant progression of breast cancer.33 Altogether, these observations reveal that aberrant functionality of the CDK4/6-USP51-ZEB1 axis might contribute to metastasis and could be used to predict poor clinical outcomes in breast cancer patients. This evidence concerns the gene CDK4 and breast cancer.