ALK and lung cancer: Nowadays, tyrosine kinase inhibitors (TKIs) targeting the genomic alternations such as epidermal growth factor receptor (EGFR) mutation, anaplastic lymphoma kinase (ALK)-rearrangement and Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) mutations are currently in clinical development and are proven to markedly improve survival in lung cancer [6].