These include the breast cancer progenitors, SEMA5A, KITL, CAV2, EPS8 and PKP4, and the Rb1-targeted senescence-associated proteins, FRMD4A, SKA2, PRR11 and ITGBL1. Additionally, these genes encode proteins that are also involved in biological adhesion, cellular proliferation, cytoskeleton function, locomotion, movement of the cell or a subcellular component, or protein modification processes. Here, PKP4 is linked to breast cancer.