Cytoplasmic MUC1 in PanIN-1

To the Editors: In a recent issue of Clinical Cancer Research , Dr. Gold describes MUC1 as a biomarker of pancreatic intraepithelial neoplasm of low grade (PanIN-1) using PAM4 monoclonal antibodies (mAb; ref. [1][1]). This claim is questionable. PAM4 mAb does not react in normal pancreas, but