MUC1 and cancer: A sandwich ELISA assay consisting of capture mAb MPR2G10 and detecting biotinylated mAb MPR4B3 could readily detect the MUC1-ARF protein (see below section "Endogenous MUC1-ARF protein is detected in human cancer cell lines"), and although the anti-MUC1-ARF mAbs recognize discrete epitopes in the MUC1-ARF repeat sequence, they all bind to the MUC1-ARF protein.