Volunteer selection criteria (Cyprus National Bioethics Committee protocol number EEBK/ΕΠ/2015/38)
(i) male or female, 50 to 70 years old, undergoing routine colonoscopy
(ii) without personal history of CRC or IBD
(iii) without having antibiotics or suffering from gastroenteritis during the month before colonoscopy.
During colonoscopy a gastroenterologist scans and samples visible tumours, while histopathologists assess the number, size and the degree of malignancy of such tumours. Volunteers are then categorized as:
(i) Healthy-appearing (bearing no or nonCRC-prone tumours)
(ii) CRC-prone (per Lieberman et al Gastroenterology 2012, when bearing ≥3 adenomas/serrated polyps, or ≥1 adenoma/serrated polyp ≥1cm, or ≥1 villus adenoma, or High-Grade Dysplasia)
(iii) CRC patients (bearing invasive tumours)
At least 32 of the “CRC-prone” volunteers, considered to be at risk for CRC, will be compared at multiple levels of molecular analysis with at least 64 healthy-appearing volunteers bearing no detectable tumours. “CRC patients” will be excluded due to potential secondary effects on the colonic mucosa.