TP63 also known as the p63 gene was discovered 20 years after the the discovery of the p53 tumor suppressor gene and along with p73 constitutes the p53 gene family based on their structural similarity.Tumor protein p63 is a member of the p53 family of transcription factors. p63 mice have several developmental defects which include the lack of limbs and other tissues, such as teeth and mammary glands, which develop as a result of interactions between mesenchyme and epithelium.p63 immunostaining has utility for differentiating prostatic adenocarcinoma (the most common type of prostate cancer) and benign prostatic tissue; normal prostatic glands stain with p63 (as they have basal cells), while the malignant glands in prostatic adenocarcinoma (which lacks these cells) do not.