The NCI-H82 cell line was derived by A.F. Gazdar and associates in 1978 from the pleural fluid of a patient with small cell cancer of the lung. The morphology of the original tumor was not characteristic of SCLC. The line is a biochemical and morphological variant of SCLC that expresses neuron specific enolase and the brain isoenzyme of creatine kinase. It does not have detectable levels of L-DOPA decarboxylase or bombesin. The cells produce an abnormally sized p53 mRNA (3.7 kb). C-myc DNA sequences are amplified about 25 fold, and there is a 24 fold increase in c-myc RNA relative to normal cells. The cells are reported to express functional ANP receptors, but treatment with ANP does not alter their growth pattern. The cells stain positively for neurofilaments and vimentin. There is expression of v-fes, v-fms, Ha-ras, Ki-ras, N-ras and c-raf 1 mRNAs.