Mucinous carcinoma (MC) of the ovary is rare, accounting for only 4% of cases, with the majority being diagnosed at stage I. Key genetic features of MC include mutations in KRAS, present in 40–50% of cases, and HER2/ERBB2 amplification, which occurs in 19% of cases [81]. This evidence concerns the gene ERBB2 and mucinous adenocarcinoma.