Roles of tumor heterogeneity in the development of drug resistance: A call for precision therapy.

The drug resistance limits the optimal efficacy of drugs during target therapies for lung cancer and requires the development of precision medicine to identify and develop new highly selective drugs and more precise tailoring of medicine to the target population. Lung cancer heterogeneity as a potential cause of drug resistance to targeted therapy may foster tumor evolution and adaptation and fade personalized-medicine strategies. The present review elucidates the influence of tumor heterogeneity on drug efficacy and resistance, and discusses potential strategies to combat heterogeneity for cancer treatment. There is an urgent need to discover and develop disease- and biology-specific biomarkers for monitoring the existence and occurrence of lung cancer heterogeneity, testing targeted drugs in clinical trials, and implementing precision medicine for patients. Better understanding of lung cancer heterogeneity will strengthen therapeutic strategies and apply precision medicine to cure the disease.