title: Assessment of epidermal growth factor receptor (EGFR) expression in primary colorectal carcinomas and their related metastases on tissue sections and tissue microarray.
abstract: Metastatic colorectal carcinomas (CRC) resistant to chemotherapy may benefit from targeting monoclonal therapy cetuximab when they express the epidermal growth factor receptor (EGFR). Because of its clinical implications, we studied EGFR expression by immunohistochemistry on tissue sections of primary CRC (n=32) and their related metastases (n=53). A tissue microarray (TMA) was generated from the same paraffin blocks to determine whether this technique could be used for EGFR screening in CRC. On tissue sections, 84% of the primary CRC and 94% of the metastases were EGFR-positive. When matched, they showed a concordant EGFR-positive status in 78% of the cases. Moreover, staining intensity and extent of EGFR-positive cells in the primary CRC correlated with those observed in the synchronous metastases. On TMA, 65% of the primary CRC, 66% of the metastases, and 43% of the matched primary CRC metastases were EGFR-positive. There was no concordant EGFR status between the primary and the metastatic sites. A strong discrepancy of EGFR status was noted between TMA and tissue sections. In conclusion, EGFR expression measured in tissue sections from primary CRC and their related metastases was found to be similar and frequent, but it was significantly underestimated by the TMA technique.
authors.affiliation: Department of Pathology, Centre Régional de Lutte Contre le Cancer Val d'Aurelle, 34298, Montpellier, Cedex 5, France. fbibeau@valdorel.fnclcc.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bibeau
authors.forename: Florence
authors.initials: F
authors.lastname: Boissière-Michot
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Sabourin
authors.forename: Sophie
authors.initials: S
authors.lastname: Gourgou-Bourgade
authors.forename: Michèle
authors.initials: M
authors.lastname: Radal
authors.forename: Frédérique
authors.initials: F
authors.lastname: Penault-Llorca
authors.forename: Philippe
authors.initials: P
authors.lastname: Rochaix
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnould
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Bralet
authors.forename: David
authors.initials: D
authors.lastname: Azria
authors.forename: Marc
authors.initials: M
authors.lastname: Ychou
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000556:secondary; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006652:Histological Techniques; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D046888:Tissue Array Analysis
chemical_list: D066246:ErbB Receptors