MUC1 and neoplasm: We found that two of the MUC1 antibodies (H7L1 and H9K4) showed some staining of HEK293, a cell line that does not express MUC1, indicating non-specific binding, and 3 of the antibodies did not recognize any MUC1 on the cells (H17K7, H21K7 and H22K7), whereas all other antibodies exhibited specificity for hypoglycosylated MUC1 found only on tumor cells.