Causal association between metabolites and upper gastrointestinal tumors: A Mendelian randomization study.

Upper gastrointestinal (UGI) tumors, notably gastric cancer (GC) and esophageal cancer (EC), are significant global health concerns due to their high morbidity and mortality rates. However, only a limited number of metabolites have been identified as biomarkers for these cancers. To explore the association between metabolites and UGI tumors, the present study conducted a comprehensive two­sample Mendelian randomization (MR) analysis using publicly available genetic data. In the present study, the causal relationships were examined between 1,400 metabolites and UGI cancer using methods such as inverse variance weighting and weighted medians, along with sensitivity analyses for heterogeneity and pleiotropy. Functional experiments were conducted to validate the MR results. The analysis identified 57 metabolites associated with EC and 58 with GC. Key metabolites included fructosyllysine [EC: Odds ratio (OR)=1.450, 95% confidence interval (CI)=1.087­1.934, P=0.011; GC: OR=1.728, 95% CI=1.202­2.483, P=0.003], 2'­deoxyuridine to cytidine ratio (EC: OR=1.464, 95% CI=1.111­1.929, P=0.007; GC: OR=1.464, 95% CI=1.094­1.957, P=0.010) and carnitine to protonylcarnitine (C3) ratio (EC: OR=0.655, 95% CI=0.499­0.861, P=0.002; GC: OR=0.664, 95% CI=0.486­0.906, P=0.010). Notably, fructosyllysine levels and the 2'­deoxyuridine to cytidine ratio were identified as risk factors for both EC and GC, while the C3 ratio served as a protective factor. Functional experiments demonstrated that fructosyllysine and the 2'­deoxyuridine to cytidine ratio promoted the proliferation of EC and GC cells, whereas carnitine inhibited their proliferation. In conclusion, the present findings provide insights into the causal factors and biomarkers associated with UGI tumors, which may be instrumental in guiding targeted dietary and pharmacological interventions, thereby contributing to the prevention and treatment of UGI cancer.

Phosphate-to-alanine ratio and bilirubin-to-androsterone glucuronide ratio are the hub metabolites in upper gastrointestinal cancers: a Mendelian randomisation (MR) study.

Objective: Upper gastrointestinal (UGI) cancers, particularly esophageal cancer (EC) and gastric cancer (GC) represent a significant health burden with complex etiologies. Metabolic alterations are known to play a crucial role in cancer development and progression. Identifying key metabolic biomarkers may offer insights into the pathophysiology of UGI cancers and potential therapeutic targets. This study aimed to investigate the causal associations between 1,400 types of metabolites, specifically phosphate-to-alanine and bilirubin-to-androsterone glucuronide, and the risk of developing UGI cancers using Mendelian randomisation (MR) analysis. Method: We conducted a two-sample MR study utilising genetic instruments identified from large-scale genome-wide association studies (GWASs) for metabolic traits. The outcomes were derived from GWAS datasets of UGI cancer patients, including EC and GC. Several MR methods were employed to ensure the robustness of the findings, including inverse variance weighted (IVW), MR-Egger and weighted median approaches. Results: Our analysis found a total of 44 metabolites associated with EC and 15 metabolites associated with GC. The MR analyses revealed a significant causal relationship between the phosphate-to-alanine ratio (EC: OR = 1.002,95% CI = 1.00034-1.0037, p = 0.0037; GC: OR = 1.24,95% CI = 1.046-1.476, p = 0.01) and increased risk of UGI cancers. In contrast, the bilirubin-to-androsterone glucuronide ratio (EC: OR = 0.998,95% CI = 0.997-0.999, p = 0.03; GC: OR = 0.80,95% CI = 0.656-0.991, p = 0.04) was inversely associated with the risk, suggesting a potential protective effect. Conclusion: Our findings suggest that the phosphate-to-alanine ratio and bilirubin-to-androsterone glucuronide ratio are key hub metabolites in the etiology of UGI cancers. These metabolic ratios could serve as potential biomarkers for early detection or targets for therapeutic intervention. Further research is warranted to elucidate the underlying biological mechanisms and to validate the clinical utility of these associations.