One phase I trial involved the agent 212Pb-S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraaza-1,4,7,10-tetra(2-carbamoyl-methyl)cyclododecane trastuzumab (or, 212Pb-TCMC-trastuzumab) for women or men with recurrent or refractory HER2 1+ (10% tumor staining) or greater-expressing carcinomas disseminated in the abdominal cavity after at least one line of prior chemotherapy. The gene discussed is ERBB2; the disease is neoplasm.