MUC1 and cancer: Furthermore, cancer cells that express MUC1 display increased sialyl-Tn antigen (Dalziel et al., 2001; Gill et al., 2011; Reis et al., 1998), and alterations in MUC1 affect immune detection and increase macrophage activation through binding to sialylated MUC1, promoting tumor growth (Saeland et al., 2007; Nath et al., 1999; Cascio and Finn, 2016).