DHFR and neoplasm: These tumor cells with low p16/CDKN2A expression exhibited sensitivity to various DNPS inhibitors, including LTX (GART inhibitor), mycophenolic acid, VX-944 (IMPDH inhibitor) and 6-mercaptopurine (a purine analog), as well as the antifolates methotrexate and aminopterin (dihydrofolate reductase [DHFR] inhibitors).