On the move. breast cancer cells (above) can hitch a ride on the lymphatic tissue.
Cancer turns deadly when it spreads from a tumor and attack organs throughout the body. two research groups have now demonstrated a trick tumors use to travel: they induce the growth of lymphatic vessels, which serve as highways. By identifying this strategy, the teams hope they have opened up new possibilities to stop the spread of cancer.
malignant cancer cells have no difficulty swimming in blood and lymphatic system, a network of conduits which is part of the immune system response. Previous work has shown that tumors can open a door to the rest of the body by activating the growth of blood vessels, but it is unclear if they could grow their own lymphatic vessels also. A response was possible there about 2 years, when the researchers developed the first marker that specifically mark the lymphatic vessels, which makes them easy to spot under a microscope. In the February issue of Nature Medicine , two teams reported using the new marker to watch tumors grow new lymphatic vessels to grow.
For a better look at the process, both the teams tumor cells an unfair advantage: they boosted levels of natural proteins that stimulate the growth of lymphatic vessels. Cancer researcher Mihaela Skobe Massachusetts General Hospital (MGH) in Boston and colleagues added a gene for a growth factor called VEGF-C for cancer cells of the human breast. When these cells were injected into mouse mammary pads, they formed tumors that had four and a half times the concentration of the lymphatic vessels in the form of tumors from cells with normal levels of VEGF-C gene. In addition, the more cancer cells spread to the lymph nodes and lungs of mice injected with VEGF-C cells, suggesting that the rebels tumor cells were able to use the additional lymphatics to infiltrate other body parts. Meanwhile, a team led by Steven Stacker cancer researcher at the Ludwig Institute for Cancer Research in Melbourne, Australia, reported a growth factor linked, VEGF-D, also encourages the growth of blood vessels lymph and spread of cancer.
both groups say the lymphatic system deserves more attention of cancer researchers. "This may be one of the most important steps in the spread of cancer," says Stacker. In the future, he said, it could be possible to use levels of VEGF-C and VEGF-D to predict the risk of cancer spreading from a particular tumor, information that could help doctors choose the best treatment for a patient. in addition, Stacker said, VEGF-C and VEGF-D these could be promising targets for cancer drugs.
Related Sites
MGH / Harvard Cutaneous Biology Research Center
angiogenesis Lab, Ludwig Institute for Cancer Research in Melbourne, Australia
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