The antibody for the anti-p53 tumor suppressor protein detects a 53 kDa phosphoprotein, known as the product of the p53 suppressor gene. It interacts with both the wild type and mutant versions of p53, but the test using the IHC method relies on the notable buildup of the mutant p53 protein, which has a longer half-life.1 This antibody has demonstrated nuclear staining in breast cancer, lung cancer, colorectal cancer, and urothelial cancer.