Abstract
Oral cavity and oropharyngeal cancer (oral cancer) is a deadly disease that is increasing in incidence. Worldwide 5-year survival is only 50% due to delayed intervention with more than half of the diagnoses at stage III and IV, whereas earlier detection (stage I and II) yields survival rates up to 80% to 90%. Salivary soluble CD44 (CD44), a tumor-initiating marker, and total protein levels may facilitate oral cancer risk assessment and early intervention. This study used a hospital-based design with 150 cases and 150 frequency-matched controls to determine whether CD44 and total protein levels in oral rinses were associated with oral cancer independent of age, gender, race, ethnicity, tobacco and alcohol use, and socioeconomic status (SES). High-risk subjects receiving oral cancer prevention interventions as part of a community-based program (n = 150) were followed over 1 year to determine marker specificity and variation. CD44 ≥5.33 ng/mL was highly associated with case status [adjusted OR 14.489; 95% confidence interval (CI), 5.973-35.145; P < .0001, vs. reference group CD44 <2.22 ng/mL and protein <1.23 mg/mL]. Total protein aided prediction above CD44 alone. Sensitivity and specificity in the frequency-matched study was 80% and 48.7%, respectively. However, controls were not representative of the target screening population due, in part, to a high rate of prior cancer. In contrast, specificity in the high-risk community was 74% and reached 95% after annual retesting. Simple and inexpensive salivary CD44 and total protein measurements may help identify individuals at heightened risk for oral cancer from the millions who partake in risky behaviors. Cancer Prev Res; 9(6); 445-55. ©2016 AACR.