What is a circulating tumor cell chip?

Finding just one type of blood cell amidst all these cells can be like finding a needle in a haystack.  See more blood pictures.
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On the second season of the Discovery Channel's popular television program "MythBusters," Adam and Jamie tried to determine whether modern technology could make finding a needle in a haystack easy, thus rendering that old cliché outdated. The two men used fire, water, magnets and agitators to construct elaborate machines for finding the needles, but what they expected to take only an hour or so turned into an all-day event. Even with the best technology and ideas, it seemed that finding a needle in a haystack would still be a tough task.

When it comes to cancer, the needle in the haystack is the circulating tumor cell, or CTC. This blood cell breaks free from cancerous tumors and travels through the bloodstream to other parts of the body, a process known as metastasizing, or the spreading of cancer. Many cancer deaths are attributed to this blood-based distribution of cancerous cells. But despite the damage these cells do, they're very hard to find; for every 1 billion blood cells, there may be only one circulating tumor cell [source: Anthes].

Doctors have long known that these tiny cells could determine the effectiveness of a cancer treatment -- a decrease in CTC count would indicate that the cancer was responding to the therapy, while an increase or unchanged would reveal it was time to try something else. Yet, despite the impressive bounds that medical technology has made, doctors have lacked the proper means to count these cells. Previous devices used to track CTCs were only effective in about 20 to 60 percent of patients with advanced cancer [source: Anthes]. Since these devices were only able to locate the cells in advanced patients, it may have been too late to try another means of treatment. Additionally, the devices required pre-processing that sometimes destroyed the few available circulating tumor cells, making it difficult to search for other clues about the nature of the cancer.

But at the end of 2007 came some news that we might be on the way to finding these needles in our bloodstream, with a device far more simple and straightforward than anything Adam or Jamie could whip up. The invention of the circulating tumor cell chip holds the promise of giving doctors immediate feedback on how cancer treatments are working, even in the earliest stages, allowing them to try another method if necessary. Find out more about how this invention nabs those hard-to-find circulating tumor cells on the next page.