TP53 and endometrial cancer: However, (high-grade) endometrioid endometrial cancers with TP53 mutations (which is found in about 61% of grade 3 endometrial cancers) are also included, which when molecularly classified have a similarly poor prognosis.45 49 Recent studies have shown frequent homologous recombination deficiency in p53 abnormal staining (p53abn) endometrial cancer.50