Abstract 6204: Differential gut microbiome alpha diversity in endometrial and ovarian carcinoma patients
Authors: Finnicum Casey T. , Meissner Tobias , Davis Christel , Viet Sarah , Petersen Jason L. , Deaton McKenna , Solomon Benjamin , Spanos William , Starks David , Elsey Rachel , Ehli Erik A. , Williams Casey 
Published: March 2024

Abstract
Background: Emerging research underscores the gut microbiome's critical role in cancer development, progression, and response to treatment. As a part of the “ASAP” study, which focuses on the implementation of comprehensive molecular profiling and deep clinical annotation of electronic health records in participants diagnosed with or at risk of developing cancer, we have established a microbiome-associated biobank and corresponding clinical dataset to systematically explore the dynamics of the gut microbiome as patients progress through cancer treatment. We describe a pilot project where we explore the baseline microbiome samples collected from ASAP participants, particularly from those with endometrial and ovarian carcinomas.
Methods: Stool samples from patients were collected at the time of enrollment in the ASAP study and sampling is repeated every three months to align with the additional biosampling procedures. Microbial DNA was extracted from the baseline stool samples and subjected to sequencing of the V4 region of the 16S rRNA gene. After generating species level operational taxonomic units (OTUs), alpha diversity measures were generated in the form of the inverse Simpson index. In order to determine whether there was a difference in alpha diversity between individuals with ovarian (N = 37) and endometrial (N = 35) carcinomas, we employed a t-test with 100,000 permutations to derive an empirical p-value.
Results: We present sequencing results from the initial n=297 samples. Our comparison of the alpha diversity between ASAP study participants with ovarian and endometrial carcinomas showed a significant difference between the two groups, with the ovarian cancer patients having a lower alpha diversity (empirical p-value = 0.03915). Due to the uniform sampling, biobanking, and analytical procedures, our study allows the ability to explore microbiome features amongst various cancer diagnoses while minimizing laboratory and analytical differences that plague microbiome reproducibility.
Conclusions: We observed a significant difference in alpha diversity between patients with endometrial and ovarian carcinomas. Although the current results are preliminary, the wealth of information available in the ASAP protocol will allow us to continue exploring the association of the gut microbiome with cancer and the associated treatment.
Citation Format: Casey T. Finnicum, Tobias Meissner, Christel Davis, Sarah Viet, Jason L. Petersen, McKenna Deaton, Benjamin Solomon, William Spanos, David Starks, Rachel Elsey, Erik A. Ehli, Casey Williams. Differential gut microbiome alpha diversity in endometrial and ovarian carcinoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6204.