Digital DNA Test Can Detect Ovarian Cancer

Scientists have been able to detect ovarian cancer by using a blood test for DNA shed by tumors. Details of their initial studies were published in the November 20, 2002, issue of the Journal of the National Cancer Institute (USA).

The test is based on the digital analysis of single nucleotide polymorphisms (SNPs), in which the researchers separated the two strands of code found in every gene to search for imbalances that are a hallmark of cancer cell DNA. Tumor cells have an unequal ratio of maternal and paternal alleles. Digital SNP analysis counts the alleles present in each blood sample.

Using this test on 54 blood samples from late- and early-stage ovarian cancer patients, the researchers found allelic imbalance in 87% (13 of 15) of early-stage cancers and 95% (37 of 39) of late-stage disease. No allelic imbalance was detected in 31 blood samples from healthy people.

"Digital SNP appears to detect ovarian cancers very well and is far more precise than other available tests,” says le-Ming Shih, M.D., Ph.D., pathologist and director of the study at the Kimmel Cancer Center at Johns Hopkins (Baltimore, MD, USA). However, she cautions that digital SNP is too costly and labor intensive at present to serve as a general screening test. "Currently, there still is no way to usefully screen all women for ovarian cancer.” She notes that the Hopkins research team is investigating ways of achieving the same accurate detection rate with a less costly, more efficient test that could be used on a broader scale for ovarian and other cancers.




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Hopkins Kimmel Center