Other members of the ERBB family may play important roles in activating compensatory signals; for example, acquired resistance to cetuximab in CRC has been linked to activation of ERBB2 signaling (Yonesaka et al., 2011), while acquired resistance of lung tumors to gefitinib involves activation of the PI3K pathway through ERBB3 (Engelman et al., 2007). Here, EGFR is linked to colorectal carcinoma.