ERBB2 and non-small cell lung carcinoma: Indeed, EGFR, also known as HER1, belonging to the ErbB family of structurally related RTKs that comprises four isoforms: ErbB2 (HER2), ErbB3 (HER3) and ErbB4/HER4 [98], is overexpressed and constitutively activated in 62% of NSCLC cases [99].