Word: tumorous
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
Some of these therapies prevent a class of chemicals called growth factors from reaching a tumor, blocking signals that would otherwise instruct the cell to grow out of control. Others tip the delicate balance that every cell maintains between life and death, driving cancerous cells to self-destruct. Still others block enzymes that cancer cells use to chew openings in normal tissues and give themselves room to expand. And, most famously, the class of compounds known as angiogenesis inhibitors keep tumors from building new blood vessels to supply themselves with food and oxygen. Three years ago, Nobel laureate James Watson...
Then just this year researchers at Sloan-Kettering showed that the drug could dramatically boost the effectiveness of standard colorectal-cancer chemotherapy, shrinking tumors in more than a fifth of otherwise hopeless cases. Says Sloan-Kettering's Saltz: "The fact that we got a 20% response rate is staggering." What is happening, he surmises, is that the growth-factor inhibitor weakens the tumor enough for chemotherapy to finish...
Another reason cancers grow inexorably is that unlike normal cells, which die a natural death after a fixed number of divisions, cancer cells live forever. Scientists have been looking for compounds that will rewire tumor cells so they will know when it's time to go. The research is still in its early stages, but scientists in several labs have started looking at a group of enzymes called caspaces; inhibiting these enzymes disrupts the process of DNA repair that occurs each time a cell divides...
Folkman's insight was to look for substances that prevent tumors from building those pipelines. This approach worked beautifully in mice. Now more than 50 angiogenesis inhibitors are being studied in humans with a wide range of cancers; a dozen are in the final stages of testing. Thus far, only a tiny number of human patients treated with these compounds have seen their tumors shrink or disappear. Clinicians are nonetheless encouraged; while angiogenesis inhibitors don't make cancer go away, they do appear to slow tumor growth. And that means they may work best in conjunction with some...
...many scientists focus their attention on potential weaknesses in the cancer cell, others are concentrating on the flip side--recruiting the body's immune system to seek and destroy the renegade tissues. So far, this approach has proved less successful, largely because no matter how badly they are misbehaving, tumor cells are purely homegrown and thus presumed innocent by the immune system. When it finally catches on that something is wrong, it's usually too late...