Finally, we investigated how the CDK8 substitutions affected the kinase activity by measuring phosphorylation of one of its well-validated targets: p.Ser727, of the human transcription factor STAT1.30, 31, 32, 33, 34 We used a CRISPR-Cas9-engineered human cell line (SW620 colorectal carcinoma cells) that lacks both CDK8 and CDK19 (M.J. Ortiz-Ruiz et al., Cancer Res., abstract). This evidence concerns the gene CDK8 and colorectal carcinoma.