Sex-specific metabolic features in pre-cancerous polyps identified in Puerto Rican stool samples: A pilot study

Background: Colorectal cancer (CRC) is the leading cause of cancer deaths in Puerto Rico when combining men and women, with notable differences in presentation according to sex. Men have a higher incidence of CRC, with a higher overall mortality, while women are more often diagnosed with proximal tumors that respond less effectively to conventional therapies. This pattern suggests the existence of underlying sex-specific pathways that influence CRC development. Metabolite abundance analysis offers a comprehensive approach to identifying biochemical alterations associated with disease mechanisms and progression. This study aimed to characterize metabolite differences in stool between pre-cancerous polyps and healthy samples, and to explore sex-specific metabolic differences in a Hispanic cohort. Methods: A case-control design was used to analyze stool samples from ninety-seven Puerto Rican participants (68 females, 29 males) with and without colorectal adenomas. Gas chromatography-mass spectrometry was used for metabolite identification; afterwards spectral peak data was normalized and analyzed using MetaboAnalyst 6.0 and RStudio. Significance was assessed using paired t-test for pairwise comparisons and 2-way ANOVA for multivariate analysis. Results: Fifty-nine metabolites were detected across samples, with significant abundance differences between polyps and controls observed in females: beta-alanine (adjusted p=0.0014) and N-acetyl-L-aspartic acid (adjusted p=0.0017). We observed different top metabolites in males: Thapsic acid (nominal p= 0.019) and cholesterol (nominal p = 0.035). In a multivariate analysis, seven metabolites were identified in polyps vs controls, adjusting for sex (nominal p<0.05): Nicotinic acid, beta-alanine, 3,4-Dihydroxyhydrocinnamic acid, Isoleucine, Callitrisic acid, Palmitoleic acid, and Thapsic acid. Conclusion: The different metabolite profiles observed in males versus females provide evidence supporting different carcinogenic mechanisms according to sex, which may contribute to the CRC differences in presentation and outcomes reported. The metabolites detected could be potential biomarker candidates and we will be examining microbiome integration analyses with additional samples and even matching across groups. Together, these efforts will enable a more precise delineation of sex-dependent metabolic pathways that can ultimately inform tailored CRC risk stratification and prevention strategies.