In contrast, the same effectors failed to lyse the HER-2/neu-overexpressing but HLA-A2− parental SKOV3 and breast cancer cell line SKBR3 (HLA-A2.1 was the only matching allele between the primary ovarian tumours and these tumour cell lines) or the HER-2/neu− mouse fibrosarcoma cell line MC57X(H-2b). This evidence concerns the gene ERBB2 and breast carcinoma.