The interaction between endogenous TRIM21 and mutp53 was confirmed by co-IP assays in different human cancer cell lines expressing different homozygous endogenous GOF mutp53, including breast cancer SK-BR3 (R175H) and HCC70 (R248Q) cells as well as colorectal cancer HT29 (R273H) and LS1034 (G245S) cells. Here, TRIM21 is linked to breast cancer.