Blockade of extracellular NM23 or its endothelial target slows breast cancer growth and metastasis.

Background: Nucleoside Diphosphate Kinase (NDPK), described as NM23 a metastasis suppressor, is found in the culture medium of cancer cells lines suggesting that the kinase may have an extracellular role. We propose that extracellular NM23 released from breast cancers stimulates tumor cell migration, proliferation and endothelial cell angiogenesis in support of metastasis development.

Methods: NM23 in the bloodstream of immunocompromised mice carrying human triple-negative breast cancers or in breast cancer patients was measured by ELISA.