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Updated: Feb 8, 2026

Manipulation of Gene Function in Mexican Cavefish
Published on: April 22, 2019
TYMS 2R3R polymorphism and DPYD [IVS]14+1G>A gene mutation in Mexican colorectal cancer patients
Martha Patricia Gallegos-Arreola1, Guillermo Moisés Zúñiga-González2, Josefina Yoaly Sánchez-López1
1Genetics Division, Western Biomedical Research Center, Western National Medical Center, Mexican Institute of Social Security, Guadalajara, Jalisco, Mexico.
Objective:
To examine the association between TYMS 2R3R polymorphism and DPYD [IVS]14+1G>A mutation by comparing healthy subjects with colorectal cancer (CRC) patients in the Mexican population.
Method:
Genotyping of the 2R/3R was performed by polymerase chain reaction (PCR) and [IVS]14+1G>A mutation by real-time PCR analysis.
Results:
The observed frequencies of the TYMS 2R3R polymorphism and the -[IVS]14+1G>A mutation in DPYD did not indicate an increased risk for CRC (p>0.05). However we observed an association of the 2R/2R (OR 3.08, 95% CI 1.66-6.08, p=0.0017) and heterozygous (OR 1.98, 95% CI 1.32-2.97, p=0.0012) genotypes as risk factors when comparing controls and CRC patients that were also tobacco consumers. An association between the genotype and the disease was evident. The distribution of the 2R/2R genotype and hematological toxicity (adjusted OR 2.26, 95% CI 1.54-4.45, p=0.0259), heterozygous (2R/3R) with tumor stage III-IV (OR 1.81, 95% CI 1.11-2.94, p=0.020) and 2R/2R-2R/3R in non-chemotherapy response CRC patients with hematological (OR 2.3, 95% CI 1.21-4.4, p=0.014) and gastric toxicities (OR 3.11, 95% CI 1.18-8.2, p=0.035) confirmed that this factor may significantly contribute to the CRC susceptibility.
Conclusion:
TYMS 2R3R polymorphism and the -[IVS]14+1G>A mutation in DPYD was not associated with susceptibility to CRC. However, the 2R/2R and 2R/3R genotypes of TYMS polymorphism could significantly contribute to hematological and gastric toxicity in CRC patients in this sample population.
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