Testing for Colon Cancer

In the new study, Kraus and colleagues first measured levels of the CD24 protein in 63 people with colon cancer, 19 people with adenomas, or precancerous colon growths, and 68 healthy people.

"CD24 was [dramatically] elevated in colon cancer and adenoma patients, compared with healthy subjects," Kraus says.

Then, they further tested the accuracy of the CD24 blood test in 73 people: 11 had colon cancer, 24 had adenomas, and 38 showed no signs of colon cancer.

The researchers found that the test accurately detected colorectal cancer in 92% of cases; only 8% of colon cancers were missed. It gave false-positive results to 8% of people who didn't have the cancer.

As for adenomas, the test accurately caught 84% of growths. The false-positive rate was 11%.

The next step is to validate the findings in studies of larger groups of people, Kraus says.

The test is expected to cost less than $50, she says.

This isn't the first time researchers have reported they're a step closer to developing a blood test for colon cancer. Just last year, two teams of European investigators said they had developed tests that look for genetic fingerprints of tumor growth and spread in the blood, for example.

Which tests will eventually make it out of the lab and into the clinic is still anyone's guess, doctors concede.

"People are putting a lot of thought into developing blood tests that are highly accurate and can detect colon cancer at an early stage," says Robert P. Sticca, MD, of the University of North Dakota School of Medicine and Health Sciences and moderator of a news briefing.