DNA technology shows high sensitivity for colorectal cancer from stool sample

27 August 2008

EXACT Sciences Corporation (NASDAQ: EXAS) has announced the results of a study that compared the use of stool and blood plasma samples for the detection of colorectal cancer (CRC).

The study showed that improved 'BEAMing DNA' detection technology, which was developed by Johns Hopkins University, demonstrated 92% sensitivity for detecting CRC from stool samples.

Importantly, the results showed that, using this BEAMing technology, stool-based DNA testing outperformed blood plasma testing, especially for the detection of early stage CRCs. EXACT Sciences has exclusive rights to the Johns Hopkins University BEAMing technology for use in a next generation stool-based DNA (sDNA) detection technology for CRC.

In the study, a total of 25 stool DNA samples from colorectal cancer patients were analyzed and a next-generation sDNA technology correctly identified 23 (92%) of the cancers.

In the 16 of 25 cases where there were paired stool and plasma DNA samples, the sDNA technology detected mutated DNA in stool in 14 cases (88%) while only 8 (50%) corresponding plasma DNA samples had detectable levels of mutated DNA.

Further, when late-stage disease (Stage IV) is removed from the total, non-invasive sDNA performance remained at 86% (12/14) while plasma DNA performance fell to 43% (6/14). The results of the study, Analysis of Mutations in DNA Isolated from Plasma and Stool of Colorectal Cancer Patients, were published in the August 2008 issue of the journal Gastroenterology.

“We are very excited by these latest results as they underscore the early detection power that is achievable when combining advanced detection techniques with a DNA target-rich environment like stool,” commented Jeffrey R. Luber, EXACT Sciences’ President and Chief Executive Officer.

“Although this technology is still at the very early stages of development, the results of this latest study suggest that stool, which is in immediate contact with the colorectal cancers and polyps, is the more reliable and robust source of mutated DNA when compared to blood plasma for detecting early stage colorectal cancer — an essential characteristic for a mass screening test.”

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