Abstract A05: <i>Fusobacterium nucleatum</i> and clinicopathologic features of colorectal carcinoma: Results from the ColoCare Cohort

Abstract Background: Fusobacterium nucleatum (Fn) plays an active role in normal host physiology and has been associated with colorectal carcinogenesis. To date, the role of Fn in newly diagnosed colorectal cancer patients is unclear. This is the first study to evaluate associations between Fn abundance and clinicopathologic characteristics among neoadjuvant chemotherapy naïve colorectal cancer patients. Methods: We used presurgery collected fecal stool samples from n=101 prospectively followed, newly diagnosed colorectal cancer patients from the ColoCare Cohort. Quantitative real-time polymerase chain reaction was used to amplify/detect Fn DNA in neoadjuvant chemotherapy-naïve patients, not using antibiotics for at least 1 month. Patients were classified into Fn-high (n=50) or Fn-low (n=51) groups based on median Fn Cycle thresholding (Ct) values (low≤16.72; high&amp;gt;16.72) in fecal DNA. Multivariable regression was utilized to analyze associations between Fn and clinicopathologic characteristics such as tumor stage, tumor site, and tumor grade. Results: We did not observe statistically significant differences in clinicopathologic or demographic characteristics by Fn abundance groups. Compared to the Fn-low patient group, Fn-high patients were 69% more likely to be diagnosed with stage III colorectal cancer (odds ratio [OR]=1.69, 95% confidence interval [CI] 1.56-15.93, P=0.0067), while there was no difference for stage I or II. Conclusion: Human gut microbial composition, including Fusobacterium nucleatum abundance, may be linked to colorectal cancer progression. Citation Format: Patrick Mallea, Christy A. Warby, W. Zac Stephens, Biljana Gigic, Kate Buhrke, Tengda Lin, Juergen Boehm, Sheetal Hardikar, Elisa K. Santori, Petra Schrotz-King, Martin Schneider, Alexis Ulrich, Eric A. Swanson, Adetunji T. Toriola, June Round, Cornelia M. Ulrich, Andreana N. Holowatyj, Jennifer Ose. Fusobacterium nucleatum and clinicopathologic features of colorectal carcinoma: Results from the ColoCare Cohort [abstract]. In: Proceedings of the AACR Special Conference on Modernizing Population Sciences in the Digital Age; 2019 Feb 19-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(9 Suppl):Abstract nr A05.