Prevalence of thymidylate synthase gene 5'-untranslated region variants in an Argentinean sample

Thymidylate synthase (TYMS) is a key enzyme in nucleotide synthesis and therefore, an important target of many chemotherapeutic agents. Expression of TYMS mRNA is thought to be modulated by a 28-bp tandem repeat polymorphism within its 5'-untranslated region, raising the question of this variant's utility in predicting the efficacy and toxicity of cancer treatment regimens. The aim of the present research was to describe the distribution of this TYMS polymorphism in the Argentinean population. A total of 199 randomly selected DNA samples from healthy volunteers were analyzed using polymerase chain reaction and polyacrylamide gel electrophoresis. The 2R and 3R alleles were present in 47.74 and 52.26% of samples, respectively, with frequencies of 21.6 (43), 52.3 (104), and 26.1% (52) recorded for the 2R/2R, 2R/3R, and 3R/3R genotypes, respectively. No significant difference regarding gender was observed. Our prevalence data are similar to those reported for other Caucasian populations. This opens a discussion concerning the reference population valid for comparisons and the clinical importance of this genotyping test as an additional tool in personalized medicine.