TNF and respiratory system cancer: Thus, the present study focused on two types of solid cancers with different pathological entities, pancreatic cancer “digestive system cancer” and lung cancer “respiratory system cancer.” Cumulative evidences have proven that TNF-α is a pro-cachectic protein; therefore, two SNPs of TNF-α gene, as well as miR-155 expression, have been investigated and correlated the gene genotype with risk of cancer-associated cachexia.