Ornithine decarboxylase (ODC) is a critical regulatory enzyme in the polyaminebiosynthesis pathway. In both human and animal models, ODChas been implicated as an important gene during the early stagesof tumor progression. A polymorphic site at position 316 (G to A) in the promoter regulatory region of the human ODC gene has been identified and in vitro reporter gene studies have demonstrated a three to ten-fold difference in expression between the alleles. Recent studies of prostrate and gastric cancers have implicated the A allele in conferring increased susceptibility to cancer. This association is stronger in the presence of tobacco smoke. Cancer of the head and neck caused primarily by exposure to tobacco smoke is the fifth most common cancer worldwide. Since ODC appears to increase the susceptibility of cells to proliferation, especially in the presence of tobacco exposure, it may be an important candidate gene for increased susceptibility to tobacco related squamous cell carcinoma of the head and neck (SCCHN). Here, we examined for the first time, the potential association with SCCHN risk in 273 cases and 285 age, race and gender matched controls. However, no difference in the frequency of the polymorphism between the two groups was observed (OR 0.91, 95% CI 0.7 to 1.3). Although among cases and controls, the majorityreported smoking histories, either current (48% and 25%) or former (32 and 44%) smokers respectively, an increased risk among smokers was also not observed. We concludethat it is unlikely that ODC G316A plays a significantrole in the development of SCCHN. Supported in part by NIH 1P50 CA097190.

98th AACR Annual Meeting-- Apr 14-18, 2007; Los Angeles, CA