Causal relationship between gout and liver cancer: A Mendelian randomization and transcriptome analysis

Gout is an inflammatory arthritis resulting from urate crystal deposition, now recognized as part of metabolic syndrome. Hyperuricemia, a hallmark of gout, is associated with various health complications, including liver cancer. Observational studies indicate a link between gout and increased cancer incidence. However, the causal relationship between gout and hepatocellular carcinoma remains uncertain. This study utilizes Mendelian randomization (MR) to explore this connection, minimizing confounding factors commonly present in observational studies. Genome-wide association study data for gout and liver cancer were sourced from the UK Biobank. We selected single nucleotide polymorphisms that are strongly associated with gout and liver cancer as instrumental variables for the analysis. We conducted 2-sample MR analysis using multiple MR methods (MR-Egger, weighted median, inverse variance weighting, and weighted mode) to evaluate causality. Co-localization and transcriptomic analyses were employed to identify target genes and assess their expression in hepatocellular carcinoma tissues. The 2-sample MR analysis indicated a significant causal relationship between gout and heightened liver cancer risk (P_IVW = .014). Co-localization analysis identified phosphatidylethanolamine N-methyltransferase (PEMT) as a crucial gene associated with gout (pH4 = 0.990). Transcriptomic data showed that PEMT expression was significantly higher in normal liver tissues compared to malignant samples (P < .001), and higher PEMT levels correlated with improved survival outcomes (P = .045). Immunohistochemical analysis revealed lower PEMT expression in hepatocellular carcinoma from patients with concurrent gout compared to those without (P < .05). The results indicate that gout increases the risk of hepatocellular carcinoma, with PEMT potentially playing a key role. Although this study focused on European populations, indicating a need for further research in diverse groups, the results emphasize the potential for liver cancer screening in newly diagnosed gout patients. Understanding the relationship between these conditions may inform future clinical practices and cancer prevention strategies.