A number of tumour antigen-derived autoantibodies have already been widely used as biomarkers in various types of cancer, such as p53, c-erbB-2/HER2/neu and MUC1/CA15.3 (Angelopoulou et al, 1996, 1997; Angelopoulou and Diamandis, 1997; Molina et al, 1998; Duffy, 1999). Here, ERBB2 is linked to cancer.