21 recently reported that GPNMB is a prognostic factor for non-small cell lung cancer based on ELISA. A direct comparison between these findings and our results is difficult, because GPNMB expression is as low in lung cancer cells as it is in colon, ovary, and renal cancer cells 10,11,14, and a different measuring system was employed in their study. This evidence concerns the gene GPNMB and renal carcinoma.