Content area
Full Text
Significance of this study
What is already known on this subject?
Long-standing colitis in inflammatory bowel disease patients has an increased risk of early onset colitis-associated colon cancer (CAC).
Screening colonoscopy to detect CAC or dysplasia is important to reduce mortality rates; however, protocols of detecting CAC are not optimised.
[gamma]-Glutamyltranspeptidase is a cell surface enzyme of glutathione metabolism and is highly expressed in various types of human cancers.
Disseminated ovarian cancer was instantly visualised after spray administration of a newly synthesised hydroxylmethyl rhodamine green based enzymatically activatable fluorescent probe (gGlu-HMRG) in vivo.
What are the new findings?
[gamma]-Glutamyltranspeptidase expression was higher in human colon cancer cells than in normal human colon cells.
gGlu-HMRG fluorescence colonoscopy depicted murine colitis-associated colon cancers developing in the microscopic inflammatory mucosa with a high cancer to background ratio.
By using gGlu-HMRG fluorescence-guided biopsy, all fluorescent specimens histologically contained cancer and/or low-to-high grade dysplasia.
How might it impact on clinical practice in the foreseeable future?
This cancer-targeted, probe ([gamma]-glutamyl hydroxymethyl rhodamine green; gGlu-HMRG) in vivo fluorescence-guided endoscopic imaging allows us to assist the endoscopic screening of colitis-associated cancers in patients with long-standing inflammatory bowel disease by topically spraying the probe during the colonoscopic procedure because of the rapid activation of cancer-specific fluorescence and small administration doses.
Introduction
Patients with long-standing colonic inflammation due to ulcerative colitis or Crohn's disease have an increased risk of developing early onset cancers. 1 2 Although colitis-associated colon cancer (CAC) represents only 1%-2% of colon cancer deaths, the cumulative risk of colon cancer is generally higher in ulcerative colitis patients than in normal subjects. 3-6 To detect dysplasia or early stage cancer at a surgically curable stage, colonoscopic surveillance is recommended for patients with a history of at least 8-10 years of extensive colitis or 12-15 years of left-sided colitis. 7 Detection of early tumours in a background of chronic colitis can be difficult and, therefore, guidelines recommend that two to four non-targeted biopsies be obtained for every 10 cm of colon and rectum evaluated. 8 Despite this practice, the diagnosis of CAC is often (17%-28%) delayed or missed largely because CACs are often multiple, nearly flat and broadly infiltrating and may be difficult to distinguish from background inflammation. 9 Moreover, missed cancers are often...