The use of neuroendocrine immunoperoxidase markers to predict chemotherapy response in patients with non-small-cell lung cancer.

Small-cell lung cancer (SCLC), a chemotherapy-responsive disease, is characterized by neuroendocrine properties. In contrast, non-small-cell lung cancer (NSCLC) is at best moderately responsive to chemotherapy, and only 10% to 20% of cases demonstrate neuroendocrine properties. The present study is a retrospective analysis of the use of immunoperoxidase markers for neuron-specific enolase (NSE), Leu-7, and chromogranin A in NSCLC patients treated with chemotherapy. It was designed to determine if the presence of neuroendocrine markers predict for response to chemotherapy. The diagnostic slides and blocks were obtained on 52 NSCLC patients who were treated with chemotherapy (26 responders and 26 nonresponders). Immunoperoxidase studies were performed, and slides were scored without knowledge of the patient's response. Markers were positive in responders and nonresponders, respectively, as follows: NSE, 14 of 26 (54%) versus seven of 26 (27%), P = .04; Leu-7, 11 of 25 (44%) versus five of 26 (19%), P = .08; and chromogranin A, three of 26 (12%) versus 0 of 26 (0%), P = .71. Two markers were positive in 10 of 26 responders (38%) and 0 of 26 nonresponders (0%), P less than .01. Responders with two or more positive markers showed superior survival (median, 79 weeks) compared with responders with fewer than two positive markers (median, 51 weeks) and nonresponders (median, 27 weeks). These data suggest that the presence of neuroendocrine markers in NSCLC is associated with an increased likelihood of response to chemotherapy and may add to the standard parameters (performance status, weight loss) used to select patients for chemotherapy.