Persistence of epidermal growth factor receptor and interleukin 10 in blood of colorectal cancer patients after surgery identifies patients with high risk to relapse

Purpose: Despite the great number of studies performed to detect circulating markers of disease progression in colorectal cancer, few have shown a clinical use; among those, epidermal growth factor receptor (EGFR) and, more recently, interleukin (IL)-10. In this article, we sought to investigate how primary surgery could affect expression levels of EGFR, IL-6, and IL-10 in blood from colorectal cancer patients. Experimental Design: We investigated by reverse transcriptase-PCR assay the expression at mRNA level of EGFR, IL-6, and IL-10 in blood samples taken from 56 colorectal cancer patients. Each gene expression was evaluated 1 day before and 20 days after primary surgery. Persistence of each gene in blood after surgery was then correlated to the relapse free time in a follow-up of 3 years. Results: In blood samples taken before surgery, EGFR, IL-6, and IL-10 were found expressed in 62, 100, and 100% of patients, respectively. EGFR expression, but not IL-6 and IL-10, correlates with stage of disease. In the group of 41 patients who underwent follow-up studies, EGFR was found persistently high in 67%; 94% of them had relapse. Persistence of IL-10 after surgery also identifies relapses in 89% of cases. IL-6 persistence was not found to significantly correlate to progression of disease. Conclusions: Persistence of both EGFR and IL-10 in blood of colorectal cancer patients after surgery identifies patients with high propensity to relapse. These findings may suggest a clinical use of preoperative EGFR/IL-10 reverse transcriptase-PCR assay in the prediction of tumor recurrence.