ABSTRACT

Prostate cancer is the most commonly diagnosed cancer in men in the United States and other Western nations. According to the American Cancer Society, approximately 220,800 new cases and 27,540 deaths from prostate cancer are projected to occur in the United States in 2015 (ACS 2015, Siegal et al., 2014). Despite widespread screening efforts and advancement in therapeutic regimens, incidence of prostate cancer is still on the rise and continues to be the second-leading cause of cancer-related deaths among men in the United States. The occurrence of prostate cancer seems mostly sporadic, with <10% inherited, although several genetic and environmental factors are attributed in controlling the development of this disease (Syed et al., 2007). The incidence of prostate cancer in the United States is highest among African Americans, followed by Caucasian and Hispanic men, while Asian-American men exhibit the lowest risk (Shavers et al., 2009). Geographic variations attributed to the incidence of prostate cancer exhibit higher rates in North America and northern Europe, intermediate levels in the Mediterranean region, and relatively low in many parts of Asia (Shavers et al., 2009; Zlotta et al. 2013). Although racial background and family history are the most common risk factors for prostate cancer, the other major risk factors that contribute to the development of prostate cancer are age, environmental factors, and lifestyle. Aging remains a

critical factor that seems to be responsible for the progression of prostate cancer (Moyad and Carroll 2004 a,b). The strong correlation between aging and the onset of prostate cancer is evident from pathological examination of prostate tissue in aging men (Hankey et al., 1999). There is a characteristic age-related decrease in the ratio of androgens to estrogen in men which may contribute to prostate cancer initiation. An additional strong risk factor for prostate cancer is a positive family history of the disease. There is evidence for both autosomal dominant and X-linked inheritance in families with a history of prostate cancer. Consequently, there is considerable scientifi c interest in identifying highly penetrant alleles in genes associated with hereditary prostate cancer (Kommu et al., 2004). Environmental factors also play an important role in the risk of prostate cancer; variations in dietary patterns have shown to be related to an increase in prostate cancer incidence among Asian immigrants who adopt a Western diet (Lee et al., 2007; Zhu et al., 2015). Lifestyle factors have also been implicated in the development of prostate cancer. Diet is an important part of lifestyle; ecological studies have implicated a “Western-style” diet in the development of prostate cancer (Lin et al., 2015). In fact, high incidence of prostate cancer is observed in American men consuming Western stereotypical diets, which are quite different from Asian diets. The typical Western diet contains high amounts of fats and meats, both of which have been implicated as candidate risk factors for prostate cancer. In comparison, Asian diets are low-fat, plant-based diets rich in fruits and vegetables having high fi ber content and certain beverages with high polyphenolic content.