Circulating Tumor Cells Reveal Insights Into Lung Cancers (HealthDay)

WEDNESDAY, July 2 (HealthDay News) -- A new technique for findingand analyzing stray cancer cells in the blood of lung cancer patients maymake it possible for doctors to one day not only determine the genetic"signature" of particular tumors but to monitor changes in those cells andadjust treatments accordingly.

"I think this is key to personalized medicine," said Dr. Daniel Haber,senior author of a paper detailing the technology, to be published in theJuly 24 issue of the New England Journal of Medicine but releasedearly online Wednesday. "As we get to targeted therapies in increasingnumbers, and increasing understanding about the genetics that guidetargeted therapies, we need a way to know what we're treating."

The "CTC chip" technology described in the new paper may also one dayaid in the detection of cancers that are likely to spread. "This is anearly warning sign we could use for earlier detection," said Haber, who isdirector of the Massachusetts General Hospital Cancer Center inBoston.

A previous study published in Nature used the CTC (CirculatingTumor Cells) chip technology to look at CTCs in lung, pancreatic,prostate, breast and colon cancers. The CTC chip successfully found suchcells in 99 percent of the samples.

"We're very interested in the biology of these cells because no one hasreally been able to study metastasis [spread of cancer to other parts ofthe body] in action," Haber said. "These are the cells that causemetastases and the lethality of cancer. Now that we can identify andpurify them in decent numbers, we can study and hopefully identify some oftheir vulnerabilities. It opens up a whole field of human metastasis andhuman therapies."

The CTC chip is a silicon chip about the size of a business card thathas 80,000 "columns" coded with an antibody that acts like a "glue" tocapture tumor cells "that have no business being in the blood," Haberexplained.

Haber and his colleagues analyzed blood samples from 27 patients withnon-small cell lung cancer, 23 who had EGFRgene mutations and four whodid not. CTCs were identified in all samples and in genetic analyses frommutations 92 percent of the time.

Mutations in EGFR, a protein, can help predict whether these tumorswill respond to a family of drugs called tyrosine kinase inhibitors.

"Even in the three to four months that we followed patients, thegenetic make-up of the tumors changed. Resistant mutations appear andother mutations appear, obviously because we're doing things [with drugtherapy] to the cancer," Haber said. "But the way we practice oncology wedon't typically test for that. We do one biopsy which takes a tiny, tinyamount and assume that for the rest of the course, the tumor is thesame."

"It's important to know in real time what you're treating," hecontinued. "We need to be able to follow the patient without needing tore-biopsy the tumor every time."

The technology is in its infancy, however. "This is still in a very,very early stage where it takes a long time to handle every sample, toflow the blood through the chip," Haber said. "This is a proof ofprinciple that we can do this. We need a much more automated system forlarger clinical trials."

Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in NewYork City, said that "you have to have some circulating cells to do thistest, but it's very exciting because they're getting a genetic fingerprintof a tumor which will tell an oncologist what therapy the tumor mightrespond to or not respond to.

"It's expensive, but it may well be that if we can identify patientswho can have a personalized regimen that works, we will be saving the costof treating all those patients with regimens that don't work," headded.

Two other studies looking at lung cancer are published in the Julyissue of the Journal of Thoracic Oncology.

One, a review of existing studies, concluded that analyzing so-calledvolatile organic compounds in the breath of lung cancer patients may holdpromise as a tool to detect cancer earlier. The technique deserves furtherattention, said researchers from the Cleveland Clinic.

For the second study, researchers at the University of Alabama atBirmingham found certain socioeconomic factors that may contribute to ahigher death rate among blacks with non-small cell lung cancer. Theseincluded a higher smoking rate among blacks patients than white patients;a greater delay to the start of treatment among blacks; and lesswillingness to undergo chemotherapy among blacks than their whitecounterparts.

More information

Visit the for more on lungcancer.