IL-6 mediated JAK/STAT3 signaling pathway in cancer patients with cachexia

OBJECTIVES: We investigated the changes in the IL-6 and STAT3 expression levels in cachectic and non-cachectic patients with gastric, lung and breast cancer and evaluated the association between IL-6 and STAT3 levels and cancer types in terms of cachexia condition. BACKGROUND: Cancer-associated cachexia, observed in nearly 50.80 % of cancer patients, has drawn attention in advanced patients. IL-6/JAK/STAT pathway plays an essential role in the progression of cancer cachexia through the regulation of the inflammatory response. METHODS: This study consisted of 48 gastric, breast and lung cancer patients (18 cachectic and 30 non-cachectic) and healthy individuals. Total RNA isolation and cDNA synthesis was performed after the collection of blood samples. IL-6 and STAT3 expression levels were analyzed by RT- PCR analysis. RESULTS: Our findings demonstrated that IL-6 mRNA levels considerably increased 19.89 +/- 8.25, 5.18 +/- 2.81 and 15.33 +/- 9.54-fold in gastric, lung and breast cancer patients with cachexia, respectively. Additionally, a 16.67 +/- 7.13, 14.21 +/- 11.72 and 8.85 +/- 3.89-fold increase in the STAT3 expression level was detected in cachectic gastric, lung and breast cancer patients, respectively (p<0.01). CONCLUSION: STAT3 may be considered as a therapeutic target for cachectic patients with gastric, lung and breast cancer. Furthermore, IL-6 mediates STAT3 activation in cachectic gastric and breast cancer patients (Tab. 5, Fig. 2, Ref. 62).