Smoking as a modulator of cancer biomarkers: Variation among ethnic groups

CN03-01

Cigarette smoking is thought to play a major role in the etiology of certain smoking-related cancers such as, lung, head & neck and bladder; however, data also suggest its involvement in causation of other cancers such as esophagus, pancreas and kidney. Identifying specific biomarkers associated with smoking in these cancers remains a controversial area of research. A cancer biomarkers can be defined as any substance that can be measured biologically and is associated with the risk of cancer. Biomarkers can be present in a patient’s serum or they may be genetic factors. Associating smoking with changes in known biomarkers of cancer may be an important area of research for investigating disparities in rates of smoking-related cancers in certain ethnic groups. Investigators have shown striking differences in smoking-related lung cancer risk among African-Americans and Hawaiians when compared to whites, Hispanics, and Japanese Americans. However, identifying specific biomarkers among these groups as it relates to smoking remains an understudied area of research. Cancer biomarkers that have been identified to be modulated by smoking include increased mutation frequency of the tumor suppressor gene p53, over-expression of the heterogeneous nuclear ribonucleoprotein (hnRNPB1), increased expression of NAD(P)H: quinone oxidoredutase 1 (NQO1) and increased expression of DNA methyltransferase 1 (DNMT1). Recently, other studies have shown smoking as a modulator of methylation status of specific genes, such as the hypermethylation of p16. In examining the above cancer biomarkers, factors that differ among various ethnic groups, which may affect their incidence in certain smoking-related cancers, in addition to smoking, are diet/nutrition and other environmental exposures. Therefore, addressing smoking status of patients at the time of diagnosis, nutritional status and other exposures are crucial in assessing treatment and cancer progression. Research will be discussed in this presentation examining the above biomarkers modulation by smoking, and other potential interactive factors, as a means to further understand health disparities among various ethnic groups.