The human epithelial mucin encoded by the gene MUC1 is an example of a tumor-specific antigen that is highly restricted on normal tissues but it is overexpressed on almost all human cancers (breast, ovarian, pancreatic, colorectal, lung, prostate, gastric cancers) and in particular, by primary and metastatic breast cancers (Kufe, 2009; Lakshminarayanan et al., 2012; Singh & Bandyopadhyay, 2007), thus making MUC1 a promising tumor-antigen with diagnostic as well as therapeutic potential in the management and treatment of cancer (Moore et al., 2004; Muller & Hanisch, 2002). Here, MUC1 is linked to gastric cancer.