Recent studies have found several diagnostic biomarkers for loss of muscle mass such as N‐terminal peptide of procollagen type III, C‐terminal agrin fragment, leptin, ghrelin, and obestatin6, 7 and prognostic biomarkers in cancer patients such as matrix metalloproteinases, survivin, and butyrylcholinesterase.8, 9, 10 Although GDF15 might also be a useful prognostic marker in cancer patients, the small sample size, the heterogeneous population, and the selection bias could have some impacts on the findings in this study. The gene discussed is BIRC5; the disease is cancer.