Analysis of neuroendocrine markers, HER2 and CEA before and after chemotherapy in patients with stage IIIA non-small cell lung cancer: A Cancer and Leukemia Group B study

Abstract

Several studies have suggested that biochemical or molecular markers examined in non-small cell lung cancer carry prognostic or treatment response information. Non-small cell lung cancer patients whose tumors have neuroendocrine (NE) features may be more responsive to chemotherapy. In addition, increased expression of HER2 (c- erbB-2), a membrane-bound receptor with tyrosine kinase activity, has been associated with shortened survival. The Cancer and Leukemia Group B (CALGB) performed a study of patients with stage IIIA (N2 nodes positive) non-small cell lung cancer in which patients received initial chemotherapy followed by surgery, then post-operative therapy consisting of sequential chemotherapy and radiation therapy. Since all patients underwent mediastinoscopy, this provided an opportunity to compare pre- and post-chemotherapy tumor specimens to test the hypothesis that these proteins would predict treatment response. In particular, we hypothesized that the post-chemotherapy specimens would be enriched for NE marker negative cells because of the increased sensitivity of NE positive cells to chemotherapy. We performed immunohistochemical analysis for a panel of NE markers [neuron-specific enolase (NSE), Leu-7, chromogranin A (ChrA), synaptophysin (Syn)], HER2 and CEA to determine if there was an effect of therapy on the percentage of cells expressing these markers. Secondary endpoints were a correlation with chemotherapy response and survival. Slides were scored for intensity (0–4) and percentage of cells positive (0–4). Of 61 eligible patients, there were 38 with both pre- and post-chemotherapy specimens. When both intensity of staining and percentage of positive cells were considered, post-chemotherapy specimens had a higher percentage of positive NE markers compared with pre-chemotherapy. In addition, there was no correlation between NE marker, HER2 or CEA expression (prior to or post treatment) and response to chemotherapy or survival. These data do not support the hypothesis that NE positive tumor cells are preferentially killed by chemotherapy in patients with stage IIIA non-small cell lung cancer.