Head and Neck cancer is sixth most common malignancies worldwide, with about 600,000 new cases diagnosed annually, of which 62% arise in developing countries [1, 2]. The most common head and neck cancer type is head and neck squamous cell carcinoma (HNSCC), representing >90% of cases [1]. HNSCC is a highly heterogeneous disease because of the different subsites associated with the variable range of etiological factor, patients outcome, treatment regimens, and molecular profile [3]. The anatomic subsites include oral cavity (tongue, lip, and law), pharynx (nasal cavity, oropharynx, and hypopharynx), and larynx. HNSCC is known to arise due to the interplay of an environmental and genetic factor and is highly complex in nature [1]. The major environmental chemical risk factors include smoking, tobacco/betel quid chewing, excessive alcohol consumption, and infection by certain viruses such as by high-risk human papillomaviruses (HPV) (Figure 1.1) [4-7]. The role of genetic risk factors include genetic susceptibility to a mutagen and inherited disorders such as Fanconi Anemia, Li-Fraumeni syndrome, Bloom syndrome
show more
