GDF15 and Cachexia: Some markers of cancer cachexia have been identified (growth differentiation factor 15, i.e., GDF-15 or parathyroid hormone release peptide, i.e., PTHrP) but none of them have been shown to change before the cachexia appears [6], so that “omics” studies are in development to identify novel muscular or circulating markers of cachexia [65].