-Background -Colorectal cancer is one of the main cause of cancer in the world. Colonoscopy is the best screen method, however the compliance is less than 50%. Quantification of human DNA (hDNA) in the feces may be a possible screen non-invasive method that is a consequence of the high proliferation and exfoliation of cancer cells. Objective -To quantify the human DNA in the stools of patients with colorectal cancer or polyps. Methods -Fifty patients with CRC, 26 polyps and 53 with normal colonoscopy were included. Total and human DNA were analyzed from the frozen stools. Results -An increased concentration of hDNA in the stools was observed in colorectal cancer patients compared to controls and polyps. Tumors localized in the left side of the colon had higher concentrations of hDNA. There were no difference between polyps and controls. A cut off of 0.87 ng/mL of human DNA was determined for colorectal cancer patients by the ROC curve, with a sensitivity of 66% and a specificity of 86.8%. For polyps the cut off was 0.41, the sensitivity was 41% and the specificity 77.4%. Conclusion -A higher concentration of hDNA had been found in colorectal cancer patients The quantification of hDNA from the stools can be a trial method for the diagnosis of colorectal cancer.
Background: Colorectal cancer (CRC) is one of the most frequent cancers. Genetic mutations in CRC already described can be detected in feces. Microarray methods in feces can represent a new diagnostic tool for CRC and significant improvement at public health. Aim: to analyze stool DNA by human DNA quantify and microarray methods as alternatives to CRC screening. Method: Three methods were analyzed in stool samples: Human DNA Quantify, RanplexCRC and KRAS/BRAF/PIK3CA (KBP) Arrays. Results: KBP array mutations were presented in 60.7% of CRC patients and RanplexCRC Array mutations in 61.1% of CRC patients. Sensitivity and specificity for human DNA quantification was 66% and 82% respectively. Fecal KBP Array had 35% sensitivity and 96% specificity and RanplexCRC Array method had 78% sensitivity and 100% specificity. Conclusion: Microarray methods showed promise as potential biomarkers for CRC screening; however, these methods had to be optimized to improve accuracy and applicability by clinical routine.
e22074 Background: Colorectal cancer (CRC) is the third leading cause of cancer in the world. Noninvasive screening tests have higher compliance. Changes in tumoral cells are also found in the stools after cancer cell exfoliation. Aim: to detect mutations in the stools of CRC patients and compare to mutations found in CRC tissue Methods: Patients referred for colonoscopy were divided into 3 groups: control, cancer, and polyp. The DNA was extracted from tissue and stool and it was analysed by two microarrays, the KRAS/BRAF/PIK3CA Array and the RanplexCRC Array (Randox Laboratories Ltd). Both based on the simultaneous detection of 20 mutations in KRAS, BRAF and PIK3CA and 28 mutations in KRAS, BRAF, TP53 and APC respectively. Positive tissue sample mutations were confirmed by Sanger sequencing. Results: 90 stools and 112 tissue biopsies were studied. Analysis of tissue samples was initially performed using the KRAS/BRAF/PIK3CA Array. In total mutations were detected in 16(55%) CRC, 12(45%) polyp and 2(6%) control samples. Mutations were confirmed via Sanger sequencing (76%). In the stool the frequency were 17(35%) in CRC, 10(71%) in polyp and 1(4%) in the control. Inconclusive tests were higher among the controls (32.5%) and polyps (22%), being less frequent in the CRC patients (6%). Excluding the inconclusive tests, WT genes were common in the controls (96%). The most common mutation was within KRAS codon 12. Stools samples from 48 subjects were compared to the results obtained by the RanplexCRC Array and mutations were found in 50% of CRC. KRAS/BRAF/PIK3CA Array stool results had a correlation with RanplexCRC Array in 64% of CRC patients and in 47% of polyp patients. The average human DNA in the stools was 15ng/ul in CRC patients and 0.46ng/ul in the controls (p=0.0001). Conclusions: Both arrays had a good correlation and a sensitivity between 30-50% with a high specificity (95-100%). The KRAS/BRAF/PIK3CA Array is currently optimized and recommended for assessment of tissue samples. This initial set of data however does indicate its potential applicability to stool specimens. Inconclusive tests are likely as a result of limited human DNA content within stool control samples. FAPESP (Sao Paulo Research Foundation) project 09/16618-8.
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