Since most recent results indicate strong in vivo activity of an immunoconjugate comprising the parental humanised mAb huHMFG1 and rapLRI in tumour-xenotransplanted immunodeficient mice (DL Newton, unpublished results), we believe that the novel, stable immunoenzyme derivative merits further investigation as a therapeutic agent for patients with MUC1+ malignancies. Here, MUC1 is linked to neoplasm.