Loss of Epidermal Growth Factor Receptor Expression in Lymph Node and Liver Metastases of Colon Carcinoma

Abstract

TO THE EDITOR: We read with great interest the article by Scartozzi et al published in the December 1, 2004, issue of the Journal of Clinical Oncology. In their series, epidermal growth factor receptor (EGFR) status was positive in only 53% of colorectal tumors and its status in primary tumors did not correlate with EGFR expression in related metastatic sites. We would like to emphasize that using a different test of EGFR immunohistochemical detection, we also observed this discrepancy between primary colon carcinoma and liver metastases in a series of 40 patients (25 men, 15 women; mean age, 57.5 years). All patients underwent a first hepatectomy for liver metastases; second and third hepatic resections were performed in 14 and three patients, respectively. In addition, seven patients had tumor liver biopsy. Using CONFIRM anti-EGFR (3C6) primary antibody (Ventana Medical Systems; Illkirch, France) on a Ventana NexES immunohistochemistry staining platform (Ventana Medical Systems), we analyzed EGFR expression on 40 surgically resected colon adenocarcinomas, on the 27 metastatic regional lymph nodes, and on the 64 related liver metastases. Membranous EGFR expression was detected in 1% of the tumor cells of 38 colon carcinomas (95%), 23 metastatic lymph nodes (88%), and 51 liver metastases (79%). In our series, both primary tumors and related metastases (lymph node and liver) were positive for EGFR expression in 28 patients (73%). In six patients with a positive EGFR status in colon carcinoma, EGFR expression was detected either in lymph node or in liver metastases, as listed in Table 1. Taken together, these data point out the variability of EGFR detection using different immunohistochemical methods. Even in a series of patients with a high rate of EGFR-positive colon carcinomas, immunohistochemical expression of EGFR could be lost in the related metastases. Which sample—primary or metastic tumor—is the most adequate to determine a therapeutically relevant EGFR status is yet to be solved.