**2. Epidemiology of NPC**

NPC is a rare malignancy that exhibits a distinct ethnic and geographic variation (Chang & Adami, 2006). While in most regions of the world, age standardized incidence rates for both males and females are <1 per 100,000 person-years (Chang & Adami, 2006; Chong, 2006)), higher rates are observed in a few well-defined populations. Studies have demonstrated intermediate incidence rates in several indigenous populations in Southeast Asia, the Arctic, and the Middle East/North Africa (ranging from 0.5 to 31.5 per 100,000 person-years in males and 0.1 to 11.8 person-years in females) (Chang & Adami, 2006; Parkin *et al*., 2002), and endemic rates in the natives of southern China reaching 20-30 per 100,000 person-years and 15-20 per 100,000 person-years amongst males and females, respectively, in the province of Guangdong (Ho, 1978; Yoshizaki *et al.*, 2011). In addition, within geographic regions, a distinct ethnic variation also exists. For example, in the US, rates are highest amongst Chinese Americans, followed by Filipino Americans, Japanese Americans, Blacks, Hispanics, and finally Caucasians (Burt *et al*., 1992).

Globally, there are more than 80,000 incident cases and 50,000 deaths annually due to NPC (Parkin *et al*., 2005). NPC shows a male predilection of 2-3:1 (Parkin *et al*., 2002). In low risk populations, incidence increases with age, while in high risk populations, incidence peaks in the 6th decade of life and declines thereafter. NPC is rare in pediatric populations. Thus, the highest incidence rates are observed in middle-aged men (Chang & Adami, 2006).
