In the scenery of peritoneal dissemination, the grade of the peritoneal disease defined the prognosis and four prognostic groups were identified: acellular mucin (AM), low-grade mucinous carcinoma peritonei (LGMCP), high-grade mucinous carcinoma peritonei (HGMCP), and high-grade mucinous carcinoma peritonei with signed ring cells (HGMCP-SRC). The gene discussed is MUC5AC; the disease is disease of peritoneum.