Location in the Large Bowel Influences the APC Mutations Observed in FAP Adenomas | oneFAPvoice

welcome to oneFAPvoice

- a positively charged Familial Adenomatous Polyposis community.
  • join today!
scientific articles

Location in the Large Bowel Influences the APC Mutations Observed in FAP Adenomas

key information

source: Familial cancer

year: 2010

authors: Will O C, Leedham S J, Elia G, Phillips R K, Clark S K, Tomlinson I P


The right colon differs from the left, in embryological origin, luminal environment, and function. In both sporadic colorectal cancer and Familial Adenomatous Polyposis (FAP), polyp density and cancer susceptibility vary markedly by colonic site. Adenomas in FAP have a different mutational spectrum in small intestine versus colon. This study aimed to investigate whether colonic location also influences the APC mutation spectrum in FAP. 127 1-2 mm mildly dysplastic adenomas from 5 patients with a codon 1309 germline mutation, and 41 from 3 patients with mutations proximal to codon 1265, were analysed to assess the frequency of loss of heterozygosity (LOH). We chose polyps from different locations in the colon. Immunohistochemistry for beta-catenin, caspase-3 and Ki-67 was performed to assess Wnt pathway activation, apoptosis and proliferation. In polyps from patients with a 1309 mutation, the frequency of LOH showed a gradient from rectum (highest) to caecum/ascending colon (lowest), but this was not present in patients with proximal germline APC mutations. Crypt-by-crypt analysis confirmed the LOH findings from whole polyps. Beta-catenin and caspase-3 expression showed no significant variation by colonic region, but Ki-67 expression decreased from ascending colon to rectum in tumours and normal tissue. Colonic site alters the mutational spectrum of APC, and crypt cell proliferation. The higher frequency of LOH in rectal polyps from patients with codon 1309 mutations may help to explain their increased polyp burden at this site compared with patients who have other germline APC mutations.

organization: St Mark's Hospital

DOI: 10.1007/s10689-010-9332-y

read more full text source

To improve your experience on this site, we use cookies. This includes cookies essential for the basic functioning of our website, cookies for analytics purposes, and cookies enabling us to personalize site content. By clicking on 'Accept' or any content on this site, you agree that cookies can be placed. You may adjust your browser's cookie settings to suit your preferences.
More information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.