CDKN1A and neoplasm: TGF-β-mediated expression of genes encoding pro-apoptotic factors such as the cell cycle inhibitors p15INK4B and p21CIP1 [47] is mediated by canonical Smad-dependent signaling, while the acceleration of tumor progression, survival, and EMT is activated by non-canonical TGF-β signaling such as MAPK and PI3K pathways [54].