NEW YORK, Nov. 18 - Researchers at Johns Hopkins University have developed a test for ovarian cancer that uses SNP analysis to detect tumor DNA in the blood.
The Johns Hopkins team, led by Ie-Ming Shih, compared plasma DNA from cancer patients, healthy people, and people with non-cancerous diseases. Tumors often shed large amounts of genomic DNA into the blood, and the team found eight times more DNA in the plasma of ovarian cancer patients.
Shih's team determined the allelic status of these samples with digital SNP, a technique that measures chromosomal imbalances, a molecular hallmark of cancer. Using sequences that included eight SNP markers that are often lost in ovarian cancers, they probed plasma DNA samples from 54 patients with ovarian tumors and 31 women with non-neoplastic disease.
The technique, outlined in the Nov. 20 issue of the Journal of the National Cancer Institute, identified allelic imbalances in 13 out of 15 of patients with early-stage cancer and 37 out of 39 of patients with late-stage cancer.
However, because this method does not identify the type of cancer or the tumor site, it would probably not be useful as a screen or early diagnostic. The authors suggest that a version of this test combined with a serologic biomarker might jointly provide a specific and sensitive test for cancer.