The purpose Of the present article is to review the links between cancer and cytokine expression. Cytokines are proteins produced by cells that act as mediators of cell-to-cell communication. Many recent reports indicate that uncontrolled, constitutive cytokine expression in tumors contributes to tumor growth, tumor progression and immuno-suppression, activities that dexceed their usual functions in host anti-tumor response. In addition, cancer susceptibility and severity seem to be associated with functional polymorphisms in cytokine genes. Thus, cytokine expression genomics may have clinical applications. Here we propose approaches to cancer detection hi the clinic based oil altered patterns of cytokine expression. Although the function and diagnostic importance of cytokines needs to be studied in more detail, examining the relationship between aberrant cytokine expression and cancer promises to be extremely useful for the identification of a new generation of biomarkers, and to advance cancer diagnosis, prevention, and treatment.