The expression of selected neuroendocrine markers and of anti-neoplastic cytokines (IL-2 and IL-12) in lung cancers.

We have continued our studies by detecting three markers of neuroendocrine tumours of the lungs, including chromogranin A, NSE and synaptophysin, to confirm the neuroendocrine origin of lung tumours and by examining the content of two anti-neoplastic cytokines, IL-2 and IL-12 in the tumours. The studies were performed on paraffin sections of lung carcinoids (n = 13) and small cell lung carcinomas (SCLC) (n = 15). Pronounced expression of all 3 markers of neuroendocrine tumours was detected in most of the pulmonary carcinoids and in 5/15 of SCLC. Co-expression of the two cytokines (IL-2 and IL-12) in tumour cells was detected in 12/13 patients with lung carcinoid and expression of at least one cytokine in 12/15 patients with SCLC. Significantly lower numbers of cells immunoreactive to both cytokines were detected in SCLC as compared to lung carcinoids. The studies have confirmed the literature data on the lowered secretion of IL-2 in SCLC and extend the data by supplying information on the expression of IL-12. The lowered expression of the two cytokines at the time of diagnosis may represent a prognostic factor for survival in SCLC.