Abstract: |
Ongoing advances in tobacco carcinogenesis reveal a multiplicity of factors that contribute to disease. Although head and neck cancer is defined as a single disease entity, it is comprised of heterogeneous neoplasias that in any single circumstance may reflect the effect of some but not all tobacco-carcinogens. Cancer induced by one carcinogen, such as tobacco-specific nitrosamines, may differ from cancers induced by tobacco-generated free-radical oxygen. Evidence would also say that the majority of carcinogen-related mechanisms which underlie cancer initiation, though ascribed to tobacco, may originate from a different etiology. Thus, though an individual may consume tobacco, the possibility exists that the mutational event which led to the head and neck cancer may have originated from a different exposure. The heterogeneity of tobacco-related cancers also reflects host-susceptibility factors which determine not only the frequency and type of mutational event, but also the rate in which each step of the multistage carcinogenesis pathway takes place. Critical host determinants include intrinsic xenobiotic enzymes and their polymorphic characteristics as well as individual DNA repair capacities. This report will briefly review concepts regarding tobacco-carcinogenesis and head and neck cancer. |