MUC1 and cancer: Of the various mucins, MUC1 is predominantly found in lung adenocarcinoma and correlates with disease progression.64 The Muc1 knockout mouse model has helped in understanding the critical role played by MUC1 in cancer pathobiology.65 During cancer development, epithelial cells lose their polarity resulting in reposition of MUC1 over the entire epithelial cell surface membrane, rather than just the apical surface.