Both IL-6 and its receptors (IL-6R and sIL-6R) are, indeed, upregulated in tumors [56,57,58,59,60,61] and their increased content in plasma of cancer patients correlates with a poor diagnosis [28,56,61,62], thus indicating clinical utility of IL-6 as a biomarker or therapeutic target in cancer management. This evidence concerns the gene IL6 and cancer.