CaMKI controls the progression of MCF-7 breast cancer of cells through G1 [110], potentially by regulating cdk4 and retinoblastoma protein (Rb) phosphorylation, as overexpression of the kinase-inactive CaMKI K49A mutant prevents cdk4 activation and Rb hyperphosphorylation in WI-38 fibroblasts [17]. This evidence concerns the gene RB1 and breast cancer.