Abstract 6526: Phylogenetic and metagenomic analysis of the human pancreatic cancer microbiome

Pancreatic cancer ranks third in cancer related deaths in the USA, however, no reliable theragnostic biomarker exists for the disease. The community of bacteria within the body can become dysbiotic and promote cancer through inflammation and other means. The objectives of this study were to determine the identity and abundance of bacterial species in the gut of mice before and after development of pancreatic cancer. As there can be significant variation in the genomes of different strains of bacterial species, a metagenome analysis was also performed. We hypothesized that there would be significant variation in species and genes of the gastrointestinal tract of mice before and after xenografting with pancreatic cancer. A decrease in ecological diversity was also predicted. Fifteen female SCID mice were divided into three cages. To develop the SubQ pancreatic cancer model, 5 X 106 Panc1 cells were injected at the flank. Fecal materials were collected prior to tumor cell implantation and after tumor development. DNA was extracted from the fecal material. For phylogenetic analysis the seven variable regions of the 16S rRNA gene were amplified and sequenced. Metagenomic analysis was performed as well. Average tumor size in mice after 40 days was ∼ 32 mm3. Microbial diversity was decreased in two out of the three groups of mice. Principle component analysis showed major differences between all samples. There were at least 15 OTUs in each set of samples specific to pretumor mice and 15 OTUs specific to tumor bearing mice. One genus of bacteria, Alistipes, was specific to each set of tumor bearing mice. Taxa at significantly increased abundances in tumor bearing mice included Prevotellaceae and Porpyromonadaceae. Moreover, there were several gene functions that were enriched in tumor bearing mice. This study produced data that demonstrates that there is a link between health status and the gut microbiome. However, this is not a new idea. This study could serve as foundation to establish a gut microbiota profile of pancreatic cancer. Precision medicine is becoming more common due to the decreasing costs of DNA sequencing. The findings of our investigation strengthens the hypothesis that there is an interaction between gut microbiome and pancreatic cancer development and bacteria or bacterial genes could serve as theragnostic biomarker for pancreatic cancer. Acknowledgement: This research was supported by NIH Grant# T34-GM100831, NSF-NOYCE Graduate student training award, a US Department of Education Graduate student training award to Elizabeth City State University Campus of The University of North Carolina and a University of North Carolina Collaboratory Grant award to Dr. H. Banerjee and Dr. Colby Hunter. Citation Format: Gabrielle Morgan, Colby Hunter, Michael Hall, Narendra Banerjee, Erik Armstrong, Kanisha McNeil, Karington Perry, Santanu Bhattacharya, Hirendra N. Banerjee, Krishna K. Rachamala, Shamit Dutta, Naga M. Nakka. Phylogenetic and metagenomic analysis of the human pancreatic cancer microbiome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6526.