An Overview, Current Challenges of Drug Resistance, and Targeting Metastasis Associated With Lung Cancer

Abstract Lung cancer is one of the deadliest and most common forms of cancer and is the leading global cause of cancer-related deaths in men and second only to breast cancer in women. Nonsmall-cell lung cancer (NSCLC) accounts for almost 80% of all lung cancer cases. In the past decade, discoveries regarding the molecular pathways and alterations implicated in the development and progression of lung cancer have facilitated the opening of new research avenues in the realms of therapeutics and targeted therapy, ultimately boosting clinical results. However, with the recent advancements in the treatment strategies, the prognosis of lung cancer patients is still poor, and this is due to the lack of early diagnosis, metastasis, and resistance to chemotherapeutics. Most often, by the time a patient is detected with lung cancer, metastasis has already occurred. Additionally, resistance to chemotherapeutic drugs over the course of treatment is one of the major challenges of lung cancer-associated therapies. In this context, tumor heterogeneity is the biggest culprit, owing to the fact that individual tumors are distinct at histologic and molecular levels; thus, making it even more challenging to nail down one particular mechanism of drug resistance that is common to lung cancer and its associated pathologies. This chapter discusses the basic molecular alterations in NSCLC, existing treatment strategies, drug resistance, and metastasis in NSCLC. This knowledge will aid in the identification of new targets, defining novel molecular biomarkers and how they can be exploited to improve the current state of early cancer detection and overcome drug resistance.