"In updated analysis of cohort of patients with gastrointestinal malignancies treated with fluoropyrimidines the prevalence of heterozygous and homozygous DPYD*9A genotypes were 41% and 10% respectively. The correlation between DPYD*9A genotype and dihydropyrimidine dehydrogenase deficiency clinical phenotype was not reproduced. Previously reported correlation is likely because of small sample size and selection bias."xsd:string