Mixich Francisc, Ioana Mihai, Voinea Florea, Săftoiu Adrian, Ciurea Tudorel
Department of Molecular and Cellular Biology, University of Medicine and Pharmacy, Str. Petru Rares 2, Craiova, Romania.
J Gastrointestin Liver Dis. 2007 Mar;16(1):5-10.
Tumor exfoliated cells that shed into stool are attractive targets for molecular screening and early detection of colon malignancies. Many studies have suggested that the detection of activated ras may have diagnostic or prognostic importance. The aim of this study was to establish the suitability for use in diagnostic laboratories of the noninvasive screening test of K-ras mutation determination in the stool and its routine prognostic value in colorectal cancer.
Paired stool and tissue specimens obtained after polypectomy and colorectal biopsy from 28 patients diagnosed solely by histopathological findings with primary colorectal carcinoma, were prospectively studied for K-ras codon 12 mutations by restriction endonuclease-mediated selective (REMS)-PCR.
DNA was obtained in 28 of tissue samples (100%) and 26 of stool samples (92.8%). K-ras codon 12 mutation was seen in 14 (50.0%) paired stool and tissue samples. Mutation detection was possible in 1000-fold excess of wild-type sequence. These results may be important in the design of genetic screening programs, determination of prognosis, early detection and treatment for patients with colon malignancy.
The sensitivity and specificity of K-ras determination on stool-derived DNA in patients with colorectal carcinoma, support the opportunity of a large-scale trial to validate its use as a screening test. REMS- PCR is not labor intensive, but a sensitive, rapid, and robust assay for the detection of point mutations, and was introduced by us in a routine diagnostic laboratory.
脱落至粪便中的肿瘤脱落细胞是结肠癌分子筛查和早期检测的理想靶点。许多研究表明，检测激活的ras可能具有诊断或预后意义。本研究的目的是确定粪便中K-ras突变测定的非侵入性筛查试验在诊断实验室中的适用性及其在结直肠癌中的常规预后价值。
前瞻性地对28例仅通过组织病理学检查确诊为原发性结直肠癌的患者，在息肉切除和结直肠活检后获取的配对粪便和组织标本进行限制性内切酶介导的选择性（REMS）-PCR检测K-ras密码子12突变。
28份组织样本（100%）和26份粪便样本（92.8%）获得了DNA。14对（50.0%）粪便和组织样本中检测到K-ras密码子12突变。在野生型序列过量1000倍的情况下仍可进行突变检测。这些结果对于结肠癌患者的基因筛查方案设计、预后判定、早期检测和治疗可能具有重要意义。
结直肠癌患者粪便来源DNA中K-ras测定的敏感性和特异性，支持开展大规模试验以验证其作为筛查试验的应用。REMS-PCR并不耗费人力，是一种检测点突变的灵敏、快速且可靠的检测方法，是我们在常规诊断实验室中引入的。
