Arguably metastasis is what makes cancer so dangerous: that a single malignant tumor of any size can seed further tumors throughout the body; that a diaspora of metastasized cells is exceedingly hard to eliminate once let lose. If metastasis could be blocked many forms of cancer would become tractable and far less threatening, which is a fair-sized step towards a robust cure for cancer - very much needed as a part of any package of biotechnologies aimed at greatly extending healthy human life. Thus it is promising to see signs of early progress along these lines:
In laboratory experiments, scientists have eliminated metastasis, the spread of cancer from the original tumor to other parts of the body, in melanoma by inhibiting a protein known as melanoma differentiation associated gene-9 (mda-9)/syntenin. ... With further research, the approach used by the scientists could lead to targeted therapies that stop metastasis in melanoma and potentially a broad range of additional cancers.
[Researchers] found that Raf kinase inhibitor protein (RKIP) interacted with and suppressed mda-9/syntenin. Mda-9/syntenin [was] shown in previous studies to interact with another protein, c-Src, to start a series of chemical reactions that lead to increased metastasis. ... Prior research suggests that RKIP plays a seminal role in inhibiting cancer metastasis, but, until now, the mechanisms underlying this activity were not clear.
Now that the researchers have demonstrated the ability of RKIP to inhibit mda-9/syntenin-mediated metastasis, they are focusing their attention on developing small molecules imitating RKIP that could be used as new treatments for melanoma.