Screening of specific CDK8 kinase inhibitors as targeted drugs for cancer therapy has demonstrated that inhibition of CDK8 kinase can result in decreased phosphorylation of STAT1 at S727 in a variety of cancer cells, and phosphorylation of STAT1-S727 could serve as a biomarker of CDK8 kinase activity in vitro and in vivo [75,76,77]. The gene discussed is STAT1; the disease is cancer.