PMAIP1 and neoplasm: In DLD-1 (p53S241F), SW480(p53R273H,P309S), HCT116(p53WT), and HCT116 p53−/− tumor cells expressing the exogenous R175H p53 mutant, Noxa protein expression was found to be induced, though some variation across cell lines was observed (Figure 1G).