MUC5AC and disease of peritoneum: In contrast, M staging exerts greater prognostic influence: M0 indicates absence of peritoneal dissemination, M1a denotes acellular mucin only, and M1b denotes mucin deposits containing epithelial cells—M1b is strongly associated with disease progression and poorer outcomes (27–29).The PSOGI consensus, intended to complement AJCC staging, places greater emphasis on the histopathologic characteristics and grading of peritoneal disease.