FOXM1 and breast cancer: Indeed, reconstitution of FoxM1 expression fully restored the endogenous integrin b1 expression in both USP22-null 4T1 and L2G+ TN1 breast cancer cells as determined by western blotting and qRT-PCR (Fig. 4A & 4B), which was further confirmed by flow cytometry (Fig. 4C & 4D).