ecancermedicalscience Editor-in-Chief Dr Enrique Soto Pérez de Celis talks to ecancer at ASCO 2025 about his study analysing the presence of DPYD gene variants linked to fluoropyrimidine toxicity in 208 Mexican patients with gastrointestinal cancers.

Using a genotyping array, researchers assessed 34 variants, including six classified as clinically actionable by CPIC. Only 1% of patients were found to carry actionable variants associated with intermediate metabolizer status. No patients had other high-risk variants commonly observed in Caucasian populations. While several low-frequency variants were detected, their clinical impact remains unclear.

The findings reveal a stark contrast in the prevalence of actionable DPYD variants between Mexican and predominantly European populations, suggesting that existing pharmacogenomic testing guidelines may not be suitable for admixed populations such as Hispanics/Latinos.

Dr Soto Pérez de Celis emphasises the need for larger, population-specific studies, broader variant screening through next-generation sequencing, and consideration of additional genes affecting drug metabolism to ensure equitable and accurate prediction of toxicity risks.