Blood test may determine susceptibility to bladder Ca

A new blood test can detect the abnormal pattern of chemical alteration of DNA associated with bladder cancer, suggesting it may be possible to assess susceptibility to the disease, say researchers from Brown University, Providence, RI.

In a study published online in the Journal of Clinical Oncology (Feb. 22, 2011), first author Carmen Marsit, PhD, and colleagues describe a blood test that can accurately detect biomolecular markers of bladder cancer that risky exposures may have left behind.

The test measures a pattern of methylation, a chemical alteration to DNA that affects which genes are expressed in cells, that Dr. Marsit’s team determined is associated with bladder cancer.

"What we might be measuring is an accumulated barometer of your life of exposures that then put you at risk," Dr. Marsit said. "Will you ever really figure out if eating something when you were 12 gave you cancer? Instead, we can use these kinds of markers as an integrated measure of your exposure history throughout your life."

The team studied the blood of 112 people who had bladder cancer and 118 who didn’t. That provided the pattern of methylation to look for in immune system cells in the blood. Then the researchers applied that test to the blood of a similar number of people who either had the cancer or did not, and made their predictions.

They found that they could determine who had the cancer and who did not based solely on the methylation pattern they observed. Controlling for the exposure to known risk factors that the patients reported, the researchers saw that patients with the methylation pattern were 5.2 times more likely to have bladder cancer than patients who did not have the pattern.

Dr. Marsit acknowledged that the investigators cannot be sure without further research whether the methylation markers in their immune system cells were predictors of cancer or a consequence of the cancer.