Taken together, our data showed that PpIX, a metabolite of aminolevulinic acid, activates TAp73 by several mechanisms converging on activation of its transcription activity and protein stabilization leading to the transactivation of pro-apoptotic PUMA and NOXA. Next, pharmacologically activated TAp73 compensates for p53 loss and induces apoptosis in cancer cells. Here, TP53 is linked to cancer.