Imaging and Advanced TechnologyIn Vivo Molecular Imaging of Colorectal Cancer With Confocal Endomicroscopy by Targeting Epidermal Growth Factor Receptor
Section snippets
Tumor Cell Lines
SW480 and SW620 cells32 were cultured in RPMI (with 10% fetal calf serum, 1% glutamine, 1% streptomycin, and 1% penicillin) at 37°C (5% CO2). Cells were harvested after 24–48 hours. For fluorescence-activated cell sorting (FACS), 105 tumor cells were incubated with 2.5 μL of fluorescein isothiocyanate (FITC)-labeled anti-EGFR-antibody (CBL416F; Chemicon/Millipore, Schwalbach, Germany), isotype control (36875K; Pharmingen, Germany), or no antibody (negative control). Immunohistochemistry (IHC)
Differential EGFR Expression by Tumor Cell Lines
FACS analysis confirmed the high EGFR expression of SW480 cells, whereas SW620 cells only showed an absent-to-mild EGFR staining. These patterns were paralleled by a strong specific staining of SW480 cells in IHC of cytospins in contrast to an almost absent specific staining of SW620 cells (Figure 1).
The ability of handheld CLE to discriminate EGFR expression was corroborated by visualizing unfixed tumor cells in cell culture after incubation with FITC-labeled antibody: A strong cellular signal
Discussion
In this study, the first evidence is provided that in vivo endomicroscopic molecular imaging of human CRC is possible by specifically targeting EGFR with a fluorescently labeled antibody. This approach successfully visualized and differentiated human CRC tumor types based on their EGFR expression in a rodent xenograft model in vivo. To mimic a potential topical use of such molecular imaging in CLE in humans, labeled antibody was applied to unfixed human tissue specimens, and successful
Acknowledgments
The authors thank Kathrin Kuhr, Institut für Medizinische Biometrie, Epidemiologie und Informatik, Universitätsmedizin Mainz, Germany, for help with the statistical analysis.
Aspects of this trial are part of the doctor of medicine theses of A.Z. and S.F.
References (54)
- et al.
Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology
Gastroenterology
(2008) - et al.
Epidermal growth factor-related peptides and their receptors in human malignancies
Crit Rev Oncol Hematol
(1995) - et al.
Epidermal growth factor receptor (EGFR) signaling in cancer
Gene
(2006) - et al.
KRAS wild-type state predicts survival and is associated to early radiological response in metastatic colorectal cancer treated with cetuximab
Ann Oncol
(2008) - et al.
Optical biopsy of GI lesions by reflectance-type laser-scanning confocal microscopy
Gastrointest Endosc
(2007) - et al.
Fluorescence induced with 5-aminolevulinic acid for the endoscopic detection and follow-up of esophageal lesions
Gastrointest Endosc
(2001) - et al.
Confocal laser endoscopy for diagnosing intraepithelial neoplasias and colorectal cancer in vivo
Gastroenterology
(2004) - et al.
In vivo histology of Barrett's esophagus and associated neoplasia by confocal laser endomicroscopy
Clin Gastroenterol Hepatol
(2006) - et al.
A fluorescence confocal endomicroscope for in vivo microscopy of the upper- and the lower-GI tract
Gastrointest Endosc
(2005) - et al.
Twelve colorectal cancer cell lines exhibit highly variable growth and metastatic capacities in an orthotopic model in nude mice
Eur J Cancer
(2004)
Identification of epithelial gaps in human small and large intestine by confocal endomicroscopy
Gastroenterology
Hexaminolevulinate-induced fluorescence endoscopy in patients with rectal adenoma and cancer: a pilot study
Gastrointest Endosc
Epidermal growth factor receptor-negative colorectal cancer: is there truly such an entity?
Clin Colorectal Cancer
EGFR FISH in colorectal cancer: what is the current reality?
Lancet Oncol
Cancer statistics, 2008
CA Cancer J Clin
A case-control study of screening sigmoidoscopy and mortality from colorectal cancer
N Engl J Med
Monoclonal antibodies to target epidermal growth factor receptor-positive tumors: a new paradigm for cancer therapy
Cancer
EGFR antagonists in cancer treatment
N Engl J Med
EGFR and cancer prognosis
Eur J Cancer
Epidermal growth factor receptor in colorectal carcinoma: correlation with clinico-pathological prognostic factors
Colorectal Dis
Epidermal growth factor receptor immunohistochemical reactivity in patients with American Joint Committee on Cancer Stage IV colon adenocarcinoma: implications for a standardized scoring system
Cancer
Developing inhibitors of the epidermal growth factor receptor for cancer treatment
J Natl Cancer Inst
Epidermal growth factor receptor (EGFR) expression is associated with a worse prognosis in gastric cancer patients undergoing curative surgery
World J Surg
Phase II trial of cetuximab in patients with refractory colorectal cancer that expresses the epidermal growth factor receptor
J Clin Oncol
Cetuximab monotherapy and cetuximab plus irinotecan in irinotecan-refractory metastatic colorectal cancer
N Engl J Med
Cetuximab for the treatment of colorectal cancer
N Engl J Med
KRAS mutations as an independent prognostic factor in patients with advanced colorectal cancer treated with cetuximab
J Clin Oncol
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Conflicts of interest The authors disclose the following: Peter Delaney is director of technology at Optiscan Pty, Ltd, Notting Hill, Victoria, Australia. Ralf Kiesslich and Markus F. Neurath report having received research grants from Pentax, Tokio, Japan. The remaining authors disclose no conflicts.
Funding Supported by a government grant of the “Stiftung Rheinland-Pfalz für Innovation” (961-38 62 61/821-Projekt 821) (to M.G.).