Overexpression of c-erbB2 protein correlates with disease-stage and chromosomal gain at the c-erbB2 locus in non-small cell lung cancer

Overexpression of the c-erbB2 protein is observed in a variety of malignanc ies including non-small cell lung cancer (NSCLC). We aimed to determine the rate of c-erbB2-overexpression in our tumour collection and to clarify its correlation with the chromosomal status at the c-erbB2 locus 17q21 in NSCL C. Eighty-nine NSCLC were analysed immunohistochemically using a polyclonal c-erbB2 antibody (DAKO). The staining was scored according to the guidelin es of the Clinical Trial Assay recommendations (0-3 +). Of these, 44 cases were also analysed by comparative genomic hybridisation (CGH). Overexpressi on was observed in 37% of the cases (score > 1) which was associated with h igher disease stages and a positive nodal status in adenocarcinomas. Chromo somal gains at 17q21 were clearly correlated with overexpression of the gen e (P = 0.009). In addition, there was a highly significant correlation betw een the c-erbB2 expression comparing the whole section immunostaining analy sis and a 127 lung tumour tissue array which included 74 of the 89 cases th at were analysed by the classical procedure. We conclude that c-erbB2 is a marker of tumour progression in NSCLC which can be observed on protein leve l and reflects chromosomal alterations at 17q21. (C) 2001 Elsevier Science Ltd. All rights reserved.