Rebecca J. Leary, M.D., of the Johns Hopkins Kimmel Cancer Center in Baltimore, and colleagues conducted whole-genome analyses of circulating cell-free DNA obtained from the plasma of 10 patients with colorectal and breast cancer. These results were compared with those from 10 healthy individuals in an effort to identify tumor-derived chromosomal alterations.

The researchers identified structural alterations in all patients; these alterations were not present in plasma DNA from healthy individuals. Detected alterations included chromosomal copy number changes and rearrangements and amplification of ERBB2, CDK6, and other cancer driver genes. Among cancer patients, the level of circulating tumor DNA varied from 1.4 to 47.9 percent.

"The sensitivity and specificity of this approach are dependent on the amount of sequence data obtained and are derived from the fact that most cancers harbor multiple chromosomal alterations, each of which is unlikely to be present in normal cells," the authors write. "Given that chromosomal abnormalities are present in nearly all human cancers, this approach represents a useful method for the noninvasive detection of human tumors that is not dependent on the availability of tumor biopsies."

Several authors disclosed financial ties to Inostics and Personal Genome Diagnostics.

Abstract
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