PharmGKB summary: methotrexate pathway.

Methotrexate is a folate analog that is used in the treatment of cancers (e.g. acute lymphoblastic leukemia, non-Hodgkin lymphoma, osteosarcoma, and colon cancer) and autoimmune diseases (e.g. rheumatoid arthritis, Crohn's disease, and psoriasis). In the treatment of autoimmune diseases, methotrexate is usually administrated orally or subcutaneously, whereas in the cancer treatment, it can be given orally, intramuscularly, as intrathecal injections, or as intravenous infusions (up to 12 g/m2). The pharmacokinetics and pharmacodynamics of methotrexate show large interpatient variability regardless of the route of administration or disease being treated. The goal of this study is to provide an introduction to methotrexate pharmacogenomics, showing the candidate genes in the PharmGKB methotrexate pathway, important variants, discussing key knowledge, and pointing to more in-depth resources.