Assigning a tumor to the serous category requires the presence of a TP53 mutation/abnormal “mutation pattern” p53 immunostaining, the absence of endometrioid-type mutations (although this point is debatable, as some low-grade endometrioid carcinomas with PTEN mutations acquire TP53 mutations during tumor progression, along with “serous” morphology), and the presence of high copy number alterations. The gene discussed is TP53; the disease is endometrioid adenocarcinoma.