While a low Δ40p53:p53α ratio supported p53’s canonical function, leading to an increased proportion of cells in G1 (Fig. 2), accompanied by pro-apoptotic gene expression (Fig. 3E–L), and apoptosis (Fig. 3A, Supplementary Fig. 2H), a high Δ40p53:p53α ratio was found to be associated with a reduction of the G1 population (Fig. 2), diminished apoptotic gene expression (Fig. 3M–O), and enhanced cell survival (Fig. 3B, D) in response to DOX and CIS. The gene discussed is TP53; the disease is in situ carcinoma.