c-erbB-2 protein in serum of primary lung cancer patients

We determined c-erbB-2 protein level in serum of 86 primary lung cancer patients (78 non-small cell lung carcinomas (NSCLC), 3 small cell carcinomas, 5 not histologically defined) and in 61 controls. Aim of this study was to evaluate the clinical usefulness of c-erbB-2 as marker for lung cancer diagnosis. The protein was measured with a commercially available sandwich enzyme immunoassay. Mean levels of c-erbB-2 were 72.8±122.3 fmol/ml in lung cancers and 64.6±17.5 fmol/ml in controls (P=0.2). No association was found between c-erbB-2 levels and histotype, tumor stage, sex and smoking habits. Among NSCLC, only four patients showed a c-erbB-2 concentration higher than the selected cut-off value of 99.6 fmol/ml. Subjects with levels higher than the 75th percentile in tumors (73 fmol/ml) had a shorter median survival than those with lower levels (6.3 months versus 10.0 months, P=0.003). Our results indicated that serum c-erbB-2 protein is not a reliable diagnostic marker. There is, however, a suggestion of a possible clinical usefulness in terms of survival prediction.