CAMs are stopping cancer in its metastatic tracks.

A counterintuitive idea is making the rounds in cancer research: Stickiness promotes mobility. Proteins that help cells stick together, called cellular adhesion molecules (CAMs), may be a driving force in metastasis, and they seem to be present in almost every cancer tested. The good news is that blocking CAMs seems to slow the spread of cancer. In fact, using antibodies to interfere with CAMs is promising enough to warrant a clinical trial, according to Peter Altevogt , Ph.D., at the German Cancer Research Center in Heidelberg, where a phase I trial is planned. “ Since the situation with tumor patients is so disastrous, it’s exciting, ” he said. “ Antibody-based therapy bears a lot of hope and expectation. ” But researchers are also trying to understand the underlying biology — what the CAMs do on the surface in the fi rst place, whether they transfer biochemical signals from the surface to the cell’s interior, and whether tackling them with antibodies is likely to cause a chain reaction that leads to cellular suicide. “ There’s not a huge amount of information out there, ” said Anthony Montgomery, Ph.D., a cell biologist at the University of California, San Diego. “ But it’s gaining more momentum. ” Adhesion molecules keep cells together; the CAMs sit on cell surfaces and stick to each other. Other proteins, such as eand n-cadherin, anchor cells to the matrices to form tissues. But unlike the cadherins, which form strong links, CAMs are generally like the glue on sticky notes — not overly adhesive but sticky enough to get the job done. They can be found on cells that normally stay in one place, such as epithelial cells, or cells that fl oat through the bloodstream, such as those of the immune system. A key feature of CAMs is that their presence on cancer cells indicates a worse prognosis. But why? So far, CAM research has revealed only a few scattered details about their role in cancer malignancy. “ The story is much more complicated than it was several years ago, ” said Avri Ben-Ze’ev, Ph.D., a cancer biologist at Weizmann Institute of Science in Tel Aviv, Israel. For example, there appear to be no hard-and-fast rules indicating which molecules will be found associated with which cancers.