Rapid DNA extraction protocol from stool, suitable for molecular genetic diagnosis of colon cancer

Abstract

Background: Colorectal cancer (CRC) is one of the most common forms of cancers in the world and is curable if diagnosed at the early stage. Analysis of DNA extracted from stool specimens is a recent advantage to cancer diagnostics. Many protocols have been recommended for DNA extraction from stool, and almost all of them are difficult and time consuming, dealing with high amount of toxic materials like phenol. Their results vary due to sample collection method and further purification treatment. In this study, an easy and rapid method was optimized for isolating the human DNA with reduced PCR inhibitors present in stool. Methods: Fecal samples were collected from 10 colonoscopy-negative adult volunteers and 10 patients with CRC. Stool (1 g) was extracted using phenol/chloroform based protocol. The amplification of P53 exon 9 was examined to evaluate the extraction efficiency for human genomic targets and also compared its efficiency with Machiels et al. and Ito et al. protocols. Results: The amplification of exon 9 of P53 from isolated fecal DNA was possible in most cases in 35 rounds of PCR using no additional purification procedure for elimination of the remaining inhibitors. Conclusion: A useful, rapid and easy protocol for routine extraction of DNA from stool was introduced and compared with two previous protocols.