However, mouse p53 gene contains only a promoter, which differs from the selective promoter of the human p53 gene; the alternatively spliced RNA species of tumor-suppressor gene p53 (which contains an additional 96 bases derived from intron 10) is present at approximately 25 to 30% the level of regularly spliced p53 RNA in both normal epidermal cells, carcinoma cells, and mouse liver and testis cells [21]. Here, TP53 is linked to carcinoma.