Additionally, several missense mutations in the extracellular domain (ECD, encoding amino acids 23–652), the transmembrane domain (TMD, encoding amino acids 653–675), and the intracellular domain (ICD, encoding amino acids 676–1255) of the HER2 protein have been identified as functional and oncogenic in NSCLC. Here, ERBB2 is linked to non-small cell lung carcinoma.