Enhanced performance of the lung- NEPS genes (red; see Table 1) relative to previously reported and standard reference genes traditionally used in qPCR and microarray normalization (blue). The x-axis represents the permutation score of a defined gene and the y-axis represents the average raw (non-normalized) tag count for the same gene. Data used in the graph are given in Additional file 7. Lung NEPS genes are stable and highly expressed as compared to the traditionally used genes. B2 M appears to perform the best with respect to high average tag count and low permutation score. Notably, the gene that performs the poorest is GAPDH.