CDKN2A and neoplasm: Furthermore, MDM2 is a negative regulator of p53 activity, being sequestered by p14arf (the alternate reading frame product of p16INK4A) in the nucleoli, where it prevents export of p53 from the nucleus to the cytoplasm for degradation by the 26S proteasome subunit.55 Senescence is associated with loss of p53 activity that greatly enhances the SASP,7 as confirmed by our study; small molecule drugs that can restore function of tumour‐suppressing genes such as p53 may be used as treatment for senescence‐associated conditions.