Abstract LB-272: Effect of smoking cessation on soluble CD44 levels in head and neck cancer
Authors: Alotaibi Faisal F. , Almuhaimid Turki M. , Reategui Erika , Franzmann Elizabeth , Goodwin Jarrard 
Published: August 2015

Abstract
In the past year, an estimated 55,070 individuals were diagnosed with head and neck cancer and approximately 12,000 related deaths occurred. This disease is devastating to the patients and families it affects due to its significant impact on swallowing, speech and appearance. Tobacco, the single largest risk factor for head and neck cancer, accounts for an estimated 85% of head and neck cancers. Carcinogens found in tobacco smoke induce damage to DNA leading to mutations and DNA strand breaks. When not correctly repaired, overexpression of gene products including CD44, a cancer stem cell marker, occurs. CD44 can be cleaved into a soluble form (solCD44) that is found in body fluids. CD44 levels in oral rinses distinguish head and neck cancer patients from controls with around 62% sensitivity and 88% specificity. CD44 becomes abnormally expressed in dysplasia and elevated levels of solCD44 have been found prior to clinical evidence of disease, in some cases. In this study we investigate changes in solCD44 levels with smoking cessation.
150 smokers from a South Florida community known to be at high-risk for oral cancer were recruited and enrolled in smoking cessation programs. At baseline, questions on smoking status, frequency and history were administered to participants. Oral rinses and saliva samples were also collected to determine levels of solCD44 and cotinine, which was used to confirm quit status, using ELISA assays. One year after enrollment (± 3 weeks), samples and questionnaires were taken again from participants to identify quitters and measure their CD44 levels. Results were then computed and analyzed by paired t-test using SAS University Edition.
So far, thirty-seven participants (24.6%) reported quitting smoking but only half of them (n = 13) were confirmed by cotinine (&lt;21). For confirmed quitters, the mean solCD44 dropped from 1.81 (SD = 1.29) prior to quitting to 1.65 (SD = 1.12) one year after enrollment. This association between solCD44 level and smoking cessation was not statistically significant (p = 0.65). Four out of 13 quitters had elevated CD44 levels prior to quitting. Three of 4 with elevated levels experienced drops in their CD44 levels following smoking cessation, including 2 subjects whose CD44 level returned to the normal range.
Based on this data, a larger number of quitters and/or an additional time points post quitting are needed as it might reveal more profound results. Such results would be critical, offering smoking cessation as a means for subjects with high levels of CD44 to decrease their risk of progression.
Citation Format: Faisal F. Alotaibi, Turki M. Almuhaimid, Erika Reategui, Elizabeth Franzmann, Jarrard Goodwin. Effect of smoking cessation on soluble CD44 levels in head and neck cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-272. doi:10.1158/1538-7445.AM2015-LB-272