Device can spot cancer cells in blood: U.S. study

Device can spot cancer cells in blood: U.S. study
CHICAGO (Reuters) - A highly sensitive microchip may helpdoctors detect rare traces of cancer circulating in thebloodstream, offering a way to better manage treatment, U.S.researchers said on Wednesday.
The device can isolate, count and analyze circulating tumorcells from a blood sample, the team at Massachusetts GeneralHospital and Harvard Medical School in Boston said.
These circulating tumor cells, or CTCs, are the tiniestfragments of tumors, which are carried in the blood.
Doctors have known about them for some time, but becausethey are so rare and so fragile, they have been hard to trapand study in a meaningful way.
"What our technology does is increase the sensitivity many,many fold, to a point where it can become a tool that can beused clinically," said Mehmet Toner, whose group developed thedevice.
He said routine monitoring of these cells could helpdoctors tailor treatments to patients and may one day aid withdiagnosis.
"Nine out 10 deaths in cancer are due to the metastaticprocess because the cancer spreads to other parts of the body,"said Toner, whose study appears in the journal Nature.
"These are really the cells that end up killing people."
Current blood tests to detect these rare cells involvedmany steps of mixing and spinning and shaking, often killingwhat few cells they found.
"We went to the blackboard and designed it from scratch,"Toner said in a telephone interview.
TRAPPING CANCER CELLS
The device they made uses a business-card sized siliconchip. It has microscopic posts that are coated with antibodiesthat recognize cancer cells.
As blood flows over the chip, these posts act like glue,trapping cancer cells and leaving blood cells behind.
Older methods may have produced one to five cells out of 60billion cells screened in an 8-milliliter tube of blood. Thenew device can find 1,000 cancer cells.
The researchers tested their chip against blood samplesfrom 68 patients with five types of tumors -- lung, prostate,breast, pancreatic and colorectal.
Out of 116 samples, they found circulating tumor cells inall but one sample, and none were found in samples taken fromhealthy people.
And the test was sensitive enough to detect changes incirculating tumor cell levels during treatment, with drops indetected CTC levels matching tumor shrinkage seen on standardCT scans.
"Suddenly, we have a great opportunity to have an impact incancer in major ways," Toner said.He said the technology will allow for much morepersonalized cancer care. "You get a sense of how a patient isresponding to treatment."Eventually, it also may prove useful for cancer screening.And ready access to live cancer cells will advance cancerresearch."We will start to understand the biology of cancer muchbetter," Toner said.(Editing by Maggie Fox and Xavier Briand)