Expression of functional folate receptors in multiple myeloma.

Receptor-targeted delivery of imaging and therapeutic agents has emerged as an attractive strategy to diagnosis and treat many diseases including cancer. One of the most well-studied receptors for targeted therapies is the folate receptor (FR) family. FR-α and FR-β are present on many cancers with little expression in normal tissues; leading to the testing of at least six folate-targeted drugs in human clinical trials for various cancers. However, the expression of FR in blood cancers has not been fully explored with no reports of FR expression in myelomas. Herein, we report the expression of both FR-α and FR-β on CD138 + plasma cells isolated from patients with multiple myeloma. In addition, all-trans retinoic acid was shown to increase the levels of FR-α and FR-β in two myeloma cell lines. Altogether, this data suggests that folate-targeted therapies for the treatment of multiple myeloma warrants further investigation.