ERBB2 and neoplasm: ErbB2 overexpression has been demonstrated in 30% of osteosarcomas (Gorlick et al, 1999) and in many other tumours such as breast (Pegram and Slamon, 2000), ovary (Slamon et al, 1989), lung (Scheurle et al, 2000) and gastric (Lin et al, 2000) carcinomas.