After the initial report of a statistically significantly increased risk of breast cancer in women who were homozygous for the proline allele [22], it has been found that PP variant leads to increased breast cancer risk [23], and it has also been found that R72 form of wild-type p53 is almost five times more efficient in apoptosis induction than the P72 form, which is presumed to rely on the increased localization of the R72 form of TP53 in the mitochondria when compared with the P72 form [7]. The gene discussed is TP53; the disease is breast cancer.