Although serum concentrations of IL-13 did not differ in cancer cachexia compared with non-cachectic cancer patients, we have measured significantly higher concentrations of salivary IL-13 in cachectic patients, which could imply a salivary IL-13 as a possible biomarker of cancer cachexia and possibly establish the role of salivary cytokine measurement in the advanced cancer setting as a more reliable and informative parameter, what was not known so far. The gene discussed is IL13; the disease is cancer.