Fever in cancer patients is defined as an axillary temperature higher than or equal to 38.3 °C in a single reading or an increase in body temperature above 38 °C for a period greater than or equal to one hour [3] The development of fever is a complex phenomenon, mediated by the release of proinflammatory mediators, mainly interleukin-1β (IL-1β), tumor necrosis factor alpha (TNF-α), and IL-6. This evidence concerns the gene TNF and cancer.