But, it should be noted that the levels (pg ml−1) of the cytokines observed in cancer patients in this study is approximately 100-fold lower than the 10 ng ml−1 concentrations of IL-6 and TGF-β required to significantly downregulate CYP2C19 mRNA in vitro (Aitken and Morgan, 2007). This evidence concerns the gene CYP2C19 and cancer.