Testing plasma for long DNA strands could help detect cancer

A blood test that looks for long DNA strands could represent a simple and inexpensive method for detecting cancer, according to a report published in the July 15th issue of Cancer Research.

When normal cells undergo apoptosis, small strands of DNA are released into the circulation. In contrast, the death of tumor cells releases much longer strands. By testing for these longer strands, clinicians could, in theory, detect cancers before they are clinically apparent.To test the idea, Dr. Ie-Ming Shih and colleagues, from Johns Hopkins University in Baltimore, used real-time PCR assays to test for long DNA strands in 61 patients with gynecologic and breast cancers and in 65 patients without neoplasia.The test was 62% sensitive and 100% specific in differentiating cancer patients from controls, the investigators note. In particular, the test was consistently able to discriminate benign adnexal masses from gynecologic malignancies. Before the test is ready for clinical use, several issues must be addressed, the authors state. One major concern is the relatively low sensitivity, but this could be improved by modifying the test or by combining its results with those of other tests, they add.(Source: Cancer Res 2003;63:000-000: Reuters Health: July 17, 2003:Oncolink)