Epidermal growth factor receptor mutations in colorectal cancer patients.

Purpose: The epidermal growth factor receptor (EGFR) plays an important role in tumorigenesis and tumor progression of colorectal cancer and leads to the activation of intracellular signaling pathways. The use of anti-EGFR-targeted therapy has increased for patients with colorectal cancer, but patients with EGFR mutations will be resistant to anti-EGFR-targeted therapy. The identification of gene mutations is critical in cancer treatment; therefore, the aim of this study is to investigate the incidences of EGFR mutations in colorectal cancer patients in Korea.

Methods: We retrospectively reviewed 58 colorectal cancer patients who underwent surgery between 2003 and 2006. We analyzed their EGFR mutations in four loci by DNA sequencing. In addition, we analyzed the correlation between the presence of EGFR mutation and patients' clinicopathologic features.

Results: Of the 58 patients, 35 patients were male and 23 were female. Their mean age was 63.28 ± 11.18 years. Two patients (3.45%) were diagnosed as stage Tis, 7 patients (12.07%) as stage I, 24 patients (41.38%) as stage II, 20 patients (34.48%) as stage III, and 5 patients (8.62%) as stage IV. As a result of mutational analysis, EGFR mutations on exon 20 were detected in 13 patients (22.41%, G→A transitions). No EGFR mutations were detected on exons 18, 19, and 21. EGFR mutation was increased in the earlier stage and in the absence of lymph node metastasis (P = 0.028).

Conclusion: The incidence of EGFR mutation in Korean colorectal cancer patients is 22.41%. In addition, EGFR mutation was significantly increased in the earlier stage and in the absence of lymph node metastasis.