EGFR and HER2 levels are frequently elevated in colon cancer cells

OBJECTIVE: Correlation between EGFR/HER2 protein levels and colon cancer prognosis has been suggested. However, reports on the prevalence of EGFR/HER2 overexpression have been divergent and inconclusive due to technical variations. The uncertainty of the prevalence greatly affects decisions on therapeutic interventions targeting both molecules. We aim at evaluating the prevalence and significance of EGFR/HER2 overexpression in colon cancer cell lines. METHODS: We employed normal colon epithelial cell strain FHC and examined EGFR and HER2 levels in a series of colon carcinoma cell lines using Western blotting, and evaluated the effectiveness of siRNA targeting expression of the genes to inhibit the oncogenic properties of colon cancer cells. RESULTS: We found that (1) as compared with normal colon epithelial cells, EGFR levels and HER2 levels were significantly increased in 7 of the 8 colon cancer cell lines examined (2) siRNA targeting EGFR or HER2 reduced colony formation in soft agar of SW480 colon cancer cells, and combined treatment further reduced the colony formation ability.