In addition, immunoblot analysis has shown that depletion of DNA-PKcs by shRNA or inhibitors causes the decreased amplification of dihydrofolate reductase (DHFR) on ecDNA and the elimination of ecDNA in the methotrexate (MTX)-resistant colon cancer cell line HT-29 [36]. The gene discussed is DHFR; the disease is malignant colon neoplasm.