ERBB2 and colonic neoplasm: And preclinical experiments showed that cetuximab induces HER2-HER3 dimers in colon cancer cells [89].Several small clinical reports support the importance of expression of other markers in the HER axis, suggesting that HER2 amplification and HER3 overexpression appear to be predictive markers of resistance to anti-EGFR mAb therapy [90–94].