SLC19A1 is a member of the Solute Carrier (SLC) group of membrane transporters, which encode for a membrane protein that functions as a folate carrier implicated in methotrexate cellular accumulation in pediatric acute lymphoblastic leukemia.38 Consequently, under the prism of the recent advances in this class of drugs,39 folate antagonists merit a new look in MM with low CIg. The gene discussed is CCL21; the disease is acute lymphoblastic leukemia.