Byrne CA, et al. - Researchers performed a systematic review in order to compile the current evidence on genes expressed in the skeletal muscles of humans with chronic disease-associated cachexia and/or sarcopenia (cases) compared with controls. In addition, they estimated the strength of such evidence. They analyzed a total of 27 articles in this review; of these, at least three research articles were on 18 genes. Participants were nearly 60 years of age and were male in majority; the sample size was highly variable. All four criteria used to assess the quality of molecular analysis were not fulfilled by any of the studies; there was only one study powered on the outcome of gene expression. The only gene significantly increased in cases vs healthy controls was FOXO1. A significant decrease in expression of genes involved in autophagy, apoptosis or inflammation in cases vs controls was not identified in any of the studies. The evidence thus gained on gene expression in the skeletal muscles of humans with chronic disease-associated cachexia and/or sarcopenia is not powered properly and is not homogenous; hence, it is hard to match results across studies and diseases.