RESEARCH Promoter methylation of t p in

Full list of author information is available at the end of the articlePre-neoplastic lesion classification Background Colorectal cancer (CRC), a disease arising from complex and heterogeneous etiological factors and pathogenetic mechanisms, develops in a multi-step manner from normal epithelium, through a pre-malignant lesion (adenoma), into a malignant lesion (carcinoma) [1]. Histopathological evalu-ation of early stage CRC in many cases reveals areas of adenomatous mucosa, but the presence of tissue with histo-logical features ranging from pure tubular to pure villous adenomas accompanied by dysplasia is also frequently detected in invasive colorectal cancer [1,2]. Although indi-viduals with syndromes that strongly predispose to aden-omas, e.g. familial adenomatous polyposis (FAP), invariably develop CRC by the third to fifth decade of life if these lesions are not removed [3], most adenomas (not FAP) have a low risk of progressing into cancer (about 5%) if not resected. An adenomatous polyp is a much more frequen