MRC1 and neoplasm: In this respect, we previously demonstrated that the injection of a molar excess of unlabelled (biv)anti-MMR Nbs (un-(biv)anti-MMR Nbs) was able to significantly reduce the on-target, but off-tumor accumulation of tracer amounts of radiolabelled (m)anti-MMR Nbs (especially in the liver), while minimally impacting their tumor targeting potential 21.