It is interesting to note that knockdown of CDK8 in colon cancer cell lines HCT116, LOVO, and SW480 does not appear to affect E2F1 protein levels, but does affect E2F1 transcriptional activity [33].We have also demonstrated that the decrease in cell viability of MDA-MB-468 cells treated with inhibitor 4 is dependent on the induction of STAT3 phosphorylation, and this effect is not observed in the two colon cancer cell lines used in this study. This evidence concerns the gene E2F1 and malignant colon neoplasm.