Comparison between human c-erbB-2 gene product and EGFR shows a homology of approximately 50% in aminoacid sequence. According to the aminoacid sequence inferred for c-erbB-2 protein, it was postulated that c-erbB-2 encodes a transmembrane protein similar to EGFR

We assessed the immunohistochemical expression of c-erbB-2 transmembrane receptor in 15 primary lung carcinomas using the polyclonal antibody anti-human c-erbB-2 oncoprotein. Tissue fragments routinely processed (formalin-fixed and paraffin-embedded) were then investigated for c-erbB-2 oncoprotein expression using the Avidin-Biotin Complex staining method. Tumor cells showed positive c-erbB-2 expression in 86.6% of non small cell lung carcinomas (NSCLC). Positive c-erbB-2 immunoreaction correlated with the advanced stage of the disease, with lymph node involvement and high metastasis rate. The results obtained suggest that tissue overexpression of c-erbB-2 protein in NSCLC characterizes a group of tumors with an aggressive clinical-biological behavior and poor prognosis; c-erbB-2 protein can be considered a useful tumor marker in the morphological diagnosis and monitoring the clinical behavior of these neoplasms.