It is also important to note that from the TCGA lung cancer datasets, the mRNA levels of both CDK8 and Cyclin C were slightly increased in NSCLC tissue as compared to normal lung tissue; indeed, CDK8 protein levels were rarely upregulated in eight pairs of NSCLC tissues, whereas RFC4 protein levels were significantly upregulated (Supplementary Fig. 5a). Here, CDK8 is linked to lung cancer.