ABSTRACT
A number of cancer-causing agents, also known as carcinogens, have been identi ed (Milman and Weisburger 1994). Sustained exposure to carcinogens causes irreparable genetic mutations, which increases the risk of cancer development. e carcinogenic potential of materials such as asbestos, arsenic, coal tar, heavy metals, tobacco, and dyes as well as environmental risk factors such as exposure to ultraviolet radiation is well characterized. Further, some pathogens have been recognized as cancer-causative agents (Table 34.1). For example, chronic infection with the human papillomavirus (HPV) has been linked with cervical cancer development (Wu 2004). Carcinogenic synergies between multiple agents have also been recorded. For instance, carcinogenic synergy between hepatitis B virus and a atoxin has been observed to drastically amplify the possibility of liver cancer development (Zur Hausen et al. 2006). Owing to the ubiquitous presence of carcinogens as well as numerous cases of congenital susceptibility to cancer, the prevention of the disease in its totality is extremely challenging.
