Indeed, we observed a significant dose-dependent increase in the protein expression of P21 in both lung cancer cell lines and xenografts of lung cancer cell after treatment with Biochanin A. Furthermore, treatment with Biochanin A resulted in the downregulation of the protein expression of cyclin A and CDK2 in both lung cancer cell lines and xenografts of lung cancer cell. The gene discussed is CDK2; the disease is lung cancer.