Researchers ID New Blood Test for Prostate CA

The combination of 22 biomarkers–autoantibody signatures–identified by researchers from the University of Michigan Comprehensive Cancer Center seems to be a better test than a standard PSA (prostate specific antigen) in diagnosing prostate cancer. The results of the study were published in the New England Journal of Medicine:

Researchers looked at blood samples taken from 331 prostate cancer patients prior to surgery, and from 159 control males with no history of cancer. They began by testing the samples against a library of 2,300 bacteriophage, organisms that express proteins on their surface, and were able to narrow the field to the 22 biomarkers that most often pinpointed the cancerous blood samples.
Researchers looked at blood samples taken from 331 prostate cancer patients prior to surgery, and from 159 control males with no history of cancer. They began by testing the samples against a library of 2,300 bacteriophage, organisms that express proteins on their surface, and were able to narrow the field to the 22 biomarkers that most often pinpointed the cancerous blood samples…
In the current study, researchers first tested the blood serum samples of 39 men with prostate cancer and 21 controls to identify autoantibodies against prostate cancer. Cancer patients produce antibodies that fight against proteins that play a role in cancer. The researchers scanned 2,300 autoantibodies and initially narrowed it down to 186 that reacted with blood serum from the men with prostate cancer.
This discovery phase formed the basis for the next round of tests, in which 59 prostate cancer samples and 70 control samples were tested against the 186 autoantibodies. In this phase, the researcher identified a panel of 22 compounds that best distinguished the prostate cancer blood samples from the controls. Using these 22 markers, only two of 70 controls incorrectly tested positive for prostate cancer, and seven of 59 prostate cancer samples were falsely negative.
Next, the researchers validated their findings using the remaining 128 blood serum samples. They found eight of 68 controls and 11 of 60 prostate cancer samples were misclassified. This means 88 percent of the time, samples that were not cancerous were correctly identified and 81.6 percent of the time, samples that were cancerous tested positive.
“These 22 biomarkers appear to be the right number. If you used too many or too few, the accuracy went down a bit. Our findings held up when we tested the model on an independent set of blood serum samples,” Chinnaiyan says.

The press release…
The study…