Multiple detection of genetic alterations in turners and stool

Detection of genetic alterations in exfoliated intestinal cells in stool co uld represent an alternative, noninvasive tool for the screening of colorec tal tumors. To verify this, we analyzed p53 and K-ras mutations and microsa tellite instability on 46 cases of colorectal cancer and compared the prese nce of molecular alterations in tumor tissue and stool samples from individ ual 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, D17S254 BAT25, and BAT26) was eva luated,In the 18 healthy individuals, no genetic alterations in either tiss ue or stool were detected. p53 mutations were detected in 17 (37%), K-ras a lterations 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 t issue from the same patient The presence of at least one molecular alterati on in tumor was observed in 31 (67%) of the cases. p53, K-ras mutations, an d microsatellite instabilities were detected in stool samples in 18, 40, an d 60% of patients with tumors harboring the same alterations. Due to the la rgely complementary presence of p53 and Ii-ras mutations in tumors, the use of highly sensitive procedures for stool analysis could offer a means comp etitive with colonoscopy and the fecal occult blood test.