After administration with the chemotherapeutic agent from Withania somnifera along with paclitaxel, an effective chemical agent against lung cancer, significant up-regulation of the key enzymes in tricarboxylic acid (TCA) cycle such as IDH, succinate dehydrogenase, malate dehydrogenase, and alpha-ketoglutarate dehydrogenase was observed in lung cancer bearing animals, suggesting strong anti-tumor effects of the combination therapy [67]. The gene discussed is PHGDH; the disease is lung carcinoma.