We treated human HDQ-P1 breast carcinoma cells carrying endogenous R213X nonsense mutant TP53 with G418 and examined expression of full-length p53 protein by immunofluorescence staining with FL393 polyclonal p53 antibody and the monoclonal antibody PAb421 that recognizes an epitope in the p53 C-terminus. This evidence concerns the gene TP53 and breast carcinoma.