TP53 and colonic neoplasm: Furthermore, downregulation of TAp73 was also observed in p53-WT LOVO and RKO, and p53-mutant DLD1 colon cancer cells, as well as in mouse embryonic fibroblast (MEF) cells, following cisplatin treatment at a dose that induced substantial γH2Ax and apoptosis (Fig. 1F and data not shown).