ABSTRACT
Detection of genetic alterations in exfoliated intestinal cells in stool could represent an alternative, noninvasive tool for the screening of colorectal tumors. To verify this, we analyzed p53 and K-ras mutations and microsatellite instability on 46 cases of colorectal cancer and compared the presence of molecular alterations in tumor tissue and stool samples from individual patients. p53 exons 5-8 and K-ras exons 1-2 were analyzed by denaturing gradient gel electrophoresis. For the microsatellite instability, a set of 5 microsatellite markers (D2S123, D5S346, D17S250, BAT25, and BAT26) was evaluated. In the 18 healthy individuals, no genetic alterations in either tissue or stool were detected. p53 mutations were detected in 17 (37%), K-ras alterations in 15 (33%), and microsatellite instabilities in 5 (11%) of the 46 tumors analyzed. In a side study, we analyzed the correlation in genetic alteration profiles between tumors and macroscopically normal or healthy tissue from the same patient. The presence of at least one molecular alteration in tumor was observed in 31 (67%) of the cases. p53, K-ras mutations, and microsatellite instabilities were detected in stool samples in 18, 40, and 60% of patients with tumors harboring the same alterations. Due to the largely complementary presence of p53 and K-ras mutations in tumors, the use of highly sensitive procedures for stool analysis could offer a means competitive with colonoscopy and the fecal occult blood test.
Subject(s)
DNA Mutational Analysis/methods , Genes, p53/genetics , Genes, ras/genetics , Mutation , Neoplasms/diagnosis , Neoplasms/genetics , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , Electrophoresis, Polyacrylamide Gel , Exons , Feces , Humans , Microsatellite RepeatsABSTRACT
OBJECTIVE: To classify elementary endoscopic lesions of portal hypertensive gastropathy, assess their reproducibility, prevalences, sensitivity and specificity in the diagnosis of cirrhosis of the liver. METHODS: 1) A classification of portal hypertensive gastropathy elementary lesions was defined. 2) Thirty-two endoscopists evaluated videotapes of endoscopic examinations of patients with liver cirrhosis to assess beyond-chance agreement (kappa). 3) Fifteen centres enrolled consecutive patients with or without cirrhosis of the liver and recorded portal hypertensive gastropathy pattern according to its location. RESULTS: 1) Four elementary lesions (Mosaic-Like Pattern, Red Point Lesions, Cherry Red Spots, Black-Brown Spots) were identified, and graded. 2) A fair to good beyond-chance agreement was obtained for all 4 lesions. 3) portal hypertensive gastropathy prevalence was higher in patients with cirrhosis of the liver (0.63, sensitivity) than in controls (0.17). Mosaic-like pattern was the most prevalent sign (0.54). Specificity of portal hypertensive gastropathy was 0.83. Portal hypertensive gastropathy was tentatively classified as mild or severe when mosaic-like pattern alone or red marks of any kind were present, respectively; this classification led to a further improvement in reproducibility. CONCLUSIONS: Our results suggest that a sufficient degree of agreement can be achieved in recording portal hypertensive gastropathy. Therefore, the New Italian Endoscopic Club classification should be used to evaluate the natural history of this condition.
