ACTB, CDKN1B, GAPDH, GRB2, RHOA and SDCBP were identified as constantly expressed genes with high stability (M-)values according to geNorm and NormFinder and coefficients of correlation making them suitable reference genes for expression analysis/biological normalization in neuroendocrine tumors of the lung. Here, CDKN1B is linked to lung neuroendocrine neoplasm.