DHFR and lymphoma: The important lymphoma specific up-regulated genes include Dihydrofolate reductase (DHFR); CD20 (MS4A1), Myelocytomatosis viral oncogene (MYC), DNA Polymerase-alpha 1 (POLA1), DNA Polymerase-epsilon (POLE), Ribonucleotide reductase M1 (RRM1), DNA Topoisomerase II alpha (TOP2A) and Thymidylate synthase (TYMS).