Word: tumors
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Months, years, even decades may pass. Then an ominous transition occurs. Some cells in the tumor begin secreting chemicals that attract endothelial cells -- the key components of blood vessels. These cells form capillaries that grow into the tumor. They also pump out molecular messengers called growth factors that stimulate the tumor to divide more quickly...
Angiogenesis is the harbinger of metastasis. The same vessels that feed the tumor also provide it with avenues of escape. Not all the myriad cells shed by tumors survive the turbulent voyage through the bloodstream, notes experimental oncologist Ann Chambers of the London Regional Cancer Centre in Ontario. But those that do eventually slip through blood-vessel walls with ease. Using a video camera attached to a microscopic lens, Chambers has watched in wonder as melanoma and breast-cancer cells, injected into mice, become lodged in capillary walls, then crawl out into the liver. Three days later, her camera resolves...
...subject of some 1,000 scientific papers in 1993 alone, was considered the most important cancer gene. The journal Science even named it Molecule of the Year. But now there is a new contender for notoriety -- MTS1, as Alexander Kamb and his colleagues refer to the multiple tumor- suppressor gene they have just discovered. "Multiple" refers to the fact that defects in this gene can cause many kinds of cancer, including melanoma, lung, breast and brain tumors. In fact, functional copies of MTS1 may be missing in more than 50% of all human cancers...
...attack the problem. But those that directly influence a cell's decision to divide are spurring particular interest. The protein made by the MTS1 gene seems exceptionally promising, for it has characteristics suggesting it may be easily fashioned into a drug, which then might be able to stop tumor cells in their tracks. "In terms of therapeutic potential," declares Kamb, "MTS1 may be the most important tumor-suppressor gene yet discovered...
Still, as pharmaceutical companies well know, many surprises can pop up on the way to developing a new drug, and other approaches to cancer therapy may win out in the end. Among the possibilities are anticancer vaccines designed to stimulate the immune system to combat tumors. Currently being tested in the U.S. and Canada is a vaccine that spurs an assault on the weirdly configured carbohydrates that protrude from tumor cells like spikes on a medieval ball and chain. At the meeting of the American Society for Cancer Research last week, Dr. David Berd of Thomas Jefferson University presented...