Consistently, inhibition of the folate pathway using methotrexate or knockdown of either ALDH1L2 (aldehyde dehydrogenase 1 family member L2) or MTHFD1 (methylenetetrahydrofolate dehydrogenase) blocks melanoma metastasis in vivo via hindering the survival of circulating melanoma tumors while having no impact on subcutaneous tumor growth [5]. Here, MTHFD1 is linked to melanoma.