Given the dependence of the senescence program on the tumor suppressor pathways Arf-p53 and pRB-p16INK4a [10, 1], we investigated whether differences in the proportion of SAβ-gal-positive tumor cells within the breast cancer samples correlate with alterations in p53 and p16INK4a expression. The gene discussed is CDKN2A; the disease is neoplasm.