title: Studies on the amplification of dihydrofolate reductase genes in methotrexate-resistant cultured mouse cells.
mesh_terms: D000818:Animals; D002460:Cell Line; D002469:Cell Separation; D002478:Cells, Cultured; D006224:Cricetinae; D004351:Drug Resistance; D005784:Gene Amplification; D005796:Genes; D008727:Methotrexate / Q000494:pharmacology*; D051379:Mice; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*
chemical_list: D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate