Uncontrolled chronic inflammation, in most cases due to excessive cytokine signaling through their receptors, is known to contribute to the development of tumorigenesis. Recently, it has been reported that the antiviral membrane protein IFITM3 (interferon-induced transmembrane protein 3), induced by interferon signaling as part of the inflammatory response after viral infection, contributes to the development of B-cell malignancy. The unexpected oncogenic signaling of IFITM3 upon malignant B cell activation elucidated the mechanism by which the uncontrolled expression of inflammatory proteins contributes to leukemogenesis. In this review, the potential effects of inflammatory cytokines on upregulation of IFITM3 and its contribution to tumorigenesis are discussed.