USP22 and breast cancer: As expected, the protein levels of USP22, FoxM1, and integrin b1 was markedly higher in the breast tumor tissues than those in begin tumors (Fig. 6G, 6H & s6A-D), and levels were even further elevated in metastatic tissues (Fig. 6G, 6H), further supporting our discovery that upregulated USP22 in breast cancer stem cells though FoxM1-mediated ITGB1 gene transcription for promoting breast cancer lung metastasis.