Role of autophagy in head and neck cancer and therapeutic resistance.

Head and neck squamous cell carcinomas (HNSCC) are one of the most common cancers worldwide, accounting for almost 50% of all malignancies in developing nations. Autophagy is a catabolic process involving turnover of long-lived proteins and organelles and is an important mechanism for cell survival under stress conditions. Autophagy has been shown to play a pivotal role in etio-pathogenesis of several cancers. Autophagy and apoptosis may be triggered by common upstream signals, and sometimes this results in combined autophagy and apoptosis, or defective apoptosis rendering immortalized epithelial cells highly tumorigenic. Autophagy has been found to buffer metabolic stress and may help in cell survival; however, inhibiting autophagy under conditions of nutrient limitation can restore cell death to apoptosis-refractory tumors. Therefore, autophagy acts as a double-edged sword in cancer therapeutics. Role of autophagy in pathophysiology and as a potential cancer therapeutics is a subject of intensive research. This review will focus on the role of autophagy and how it contributes to the pathogenesis and overcoming therapeutic resistance in HNSCC.