In a similar study, β-elemene which is a volatile oil isolated from Rhizoma zeodaria, was used to enhance the therapeutic efficacy of cisplatin in non-small-cell lung cancer by synergistically inducing cell cycle arrest at the G2/M phase with increased level of checkpoint kinase 2 (CHK2) and reduced activity of cell division cycle protein 2 (CDC2) 42. The gene discussed is CHEK2; the disease is non-small cell lung carcinoma.