The Effects of Environmental Factors on Carcinogenesis

Cell cycle is regulated by proto-oncogens, tumor suppressor genes, apoptosis regulating genes, DNA-repair genes and recently microRNAs.Different carcinogenic agents causeneoplastic transformation by manipulating and changing these genes and molecules.Carcinogenic agents are categorized into: chemicals, radiation and microbiologic agents.Among chemical agents, Bisphenol A is an endocrine disruptor that can disturbthe organ morphology and the development of reproductive tract. It is also considered as a risk factor for breast and prostatic cancers. Aflatoxin ingestion leads to hepatocellularcarcinoma and polycyclic hydrocarbons. Also. nitrosamines induce lung cancer. Ultraviolet radiation, specially UVB, is a known risk factor for skin cancers. Also, oncogenic viruses,either by themselves or in company with other carcinogens play important roles in neoplastic transformation in various cells