MUC5AC and adenocarcinoma: EpCAM is an antigen expressed by progenitor cells in multiple carcinomas (Baeuerle and Gires, 2007, Ricci-Vitiani et al., 2007, Yamashita et al., 2009), while MUC2 is a mucin expressed by normal colon epithelia, but differentially expressed in adenocarcinomas (Ajioka et al., 1996, Bu et al., 2010).