Study on epidermal growth factor receptor status in primary colorectal cancers and related metastatic sites / 解放军医学杂志

ABSTRACT

Objective Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of colorectal cancer (CRC). There are several potential therapies to target EGFR. The detection of EGFR expression is usually performed by immunohistochemistry (IHC) only in the primary tumor. There are a few data regarding the EGFR status in the corresponding distant metastases. The aim of the present study was to correlate EGFR expression in primary tumors and related metastases in order to find out whether EGFR status is different between primary tumors and related metastases. Methods 37 cases (25 male, 12 female) of metastatic colorectal cancer were collected. The site of primary tumor was on colon in 16 patients (43.2%) and on rectum in 21 patients (56.8%). Metastatic sites analyzed were liver in 32 patients (86.5%), inguinal lymph nodes in 5 patients (13.5%). The EGFR status of primary tumors and related metastatic sites were evaluated retrospectively. The expression of EGFR was analyzed by immunohistochemical staining (IHC), EGFR status was defined as positive if the percentage of stained malignant cells was ≥5%, and the expression feature was analyzed. Results EGFR status was positive in 25 primary tumors (67.6%), in which the corresponding metastatic site was negative in 7 cases (28.0%), whereas it was positive in 3 metastases (25.0%) from 12 cases of EGFR-negative primary cancers. The difference between the primary tumors and metastatic lesions had no statistic significance (P=0.23). Conclusion When analyzed by IHC, The difference of EGFR status has no statistic significance between the paired primary tumors and distant metastatic lesions, and 73% of samples show concordant EGFR status.