MUC1 and adenocarcinoma: Whereas binding to MUC1 IgG abs from nonmalignant control subjects are preferentially directed to variant repeats and exhibit variable binding to variant and invariant MUC1 glycopeptides, MUC1 IgG abs in patients with adenocarcinoma recognize preferentially the invariant PDTR peptide, and bind equally well to all glycopeptides [95].