Abstract 4403: The crosstalk between the tumor microbiome and epigenomic changes in penile squamous cell carcinoma

Abstract Penile squamous cell carcinoma (PSCC) is approximately three times more prevalent in Puerto Rico when compared to other ethnic groups in the United States. Moreover, the mortality rate for PSCC among Puerto Rican men is significantly higher when compared to the US population. Infection with human papillomavirus (HPV) has been identified as a risk factor for an average of 48% of PSCC cases in Puerto Rico. The molecular etiology of HPV+ and HPV- PSCC remains poorly understood. To date, the role of the microbiota in the pathogenesis of PSCC is unknown, as there are no studies that characterize the microbiome in association with penile cancer. Furthermore, the role of DNA methylation, which is an epigenetic alteration that can be found in cancer cells that can lead to changes in gene expression and cellular function, is also unknown. Therefore, there is an urgent need to address this knowledge gap. This study aims to analyze the DNA methylation patterns and bacterial communities in HPV-positive and HPV-negative PSCC tissues from Puerto Rican men. DNA was extracted from twenty-one fresh PSCC tissue samples from Puerto Rican patients. HPV status and genotyping were determined using the DNA ELISA kit HPV SPF10 protocol. DNA methylation assay was performed using the Infinium Methylation EPIC v2.0 BeadChip Kit to identify and compare average DNA methylation levels (%) in 7 HPV-positive and 14 HPV-negative penile cancer samples. Microbiota analyses were performed using 16S rRNA genes with the Illumina MiSeq platform. Demultiplexed data was deposited in QIITA for quality control and bioinformatic analyses and downstream analyses were done in R and Qiime2. Our results demonstrated that 45 loci methylation patterns were significantly different between HPV-positive and HPV-negative samples, with an adjusted p-value <0.1 (Benjamini-Hochberg method). Three loci methylation patterns were significantly affected by species diversity and richness. The abundance of Firmicutes, Proteobacteria, Bacteroidetes, Fusobacteria, and Actinobacteria was individually associated with number of affected loci (27, 19, 12, 6, and 3, respectively). We found that HPV status is associated with methylation patterns and microbiome in PSCC in Puerto Rican men. Both changes may be involved in triggering inflammatory responses and oncogenesis. Although many challenges must be overcome to dissect the specific interactions of coinfecting bacteria and methylation patterns during the penile cancer infectious process, our findings demonstrate that microbes may be involved in these cellular processes. Citation Format: Jorge Viera-Vera, Yarelis M. Roque-Reyes, Daniel Santiago-Negron, María Sánchez-Vázquez, Yakshi Ortiz Maldonado, Gabriel Borges-Vélez, Jasmine Figueroa-Díaz, Carlos A. Rivera-López, Niki M. Zacharias Millward, María J. Marcos-Martínez, Filipa Godoy-Vitorino, Antonio Puras-Baez, Julie Dutil, Josué Pérez-Santiago, Magaly Martínez-Ferrer. The crosstalk between the tumor microbiome and epigenomic changes in penile squamous cell carcinoma [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 4403.