To test the ability of Erb-hcAb to induce CDC against ErbB2-positive tumour cells, SKBR3 target cells were incubated for 2 or 6 h with Erb-hcAb (at 3 or 10 μg ml−1 concentrations) in the absence or the presence of human serum as a source of complement. This evidence concerns the gene ERBB2 and neoplasm.