New secrets behind bone metastasis.

Secreted proteins play essential roles in every step of cancer metastasis, while the identities and functions of those that contribute to tissue-specific metastasis are largely uncharacterized. Two articles in Cell Research report the discovery and functional analyses of novel secreted proteins that are biologically and clinically relevant to bone metastasis. The combinatory approaches represented here, together with advances in related technology, will promise a better understanding of the cancer secretome.