This study, through analyzing 311 gastric cancer and colorectal cancer patients, found that the inflammatory factor, IL-6, was significantly elevated in male and female patients, but TNF-α, another common inflammatory factor concerning cachexia, had no apparent change in both male and female patients, indicating that serum IL-6 might play a more important role during the progress of cachexia. This evidence concerns the gene IL6 and Cachexia.