In recent years, many personalized treatments have been developed for NSCLC 
(non-small-cell lung cancer) patients. Among these, gefitinib, erlotinib, and 
afatinib are selective epidermal growth factor receptor (EGFR) tyrosine kinase 
inhibitors for patients with EGFR gene mutations, while crizotinib and ceritinib 
are two new tyrosine kinase inhibitors directed against the echinoderm 
microtubule-like protein 4-anaplastic lymphoma kinase translocation. The 
possibility of these new molecules being used to treat patients without 
adenocarcinoma histology is notably small. For example, EGFR mutations and 
anaplastic lymphoma kinase fusion gene rearrangement are rare in patients with 
squamous cell carcinoma (generally <1%). Additionally, the benefit of targeted 
treatment approaches in patients with small-cell lung cancer histology is 
limited. All of these findings highlight the distinctive nature of 
adenocarcinoma of the lung among all lung cancer subtypes. Unfortunately, to 
date, less than 15% of patients with adenocarcinoma of the lung are ideal 
candidates for these targeted therapies.