Background: Chronic myeloid leukemia (CML) is one of the most frequent hematopoietic malignancies in the elderly population; however, knowledge is limited regarding the genetic factors associated with increased risk for CML. Polymorphisms affecting microRNA (miRNA) biogenesis or mRNA:miRNA interactions are important risk factors in the development of different types of cancer. Thus, we carried out a case-control study to test the association with CML susceptibility of gene variants located in the miRNA machinery genes AGO1 (rs636832) and GEMIN4 (rs2740348), as well as in the miRNA binding sites of the genes BRCA1 (rs799917) and KRAS (rs61764370). Materials and Methods: We determined the genotype of 781 Mexican-Mestizo individuals (469 healthy subjects and 312 CML cases) for the four polymorphisms using TaqMan probes to test the association with CML susceptibility. Results: We found a borderline association of the minor homozygote genotype of the KRAS_rs61764370 polymorphism with an increased risk for CML susceptibility (P = 0.06). After gender stratification, this association was significant only for women (odds ratio [OR] = 13.41, P = 0.04). The distribution of the allelic and genotypic frequencies of the four studied SNPs was neither associated with advanced phases of CML nor treatment response. Conclusions: To the best of our knowledge, this study is the first to show a significant association of the KRAS_rs61764370 SNP with CML. To further determine such an association of with CML susceptibility, our results must be replicated in different ethnic groups.

Chronic myeloid leukemia (CML) is one of the most frequent hematological neoplasia worldwide. The abnormal accumulation of reactive oxygen species may be an important factor in CML development. The transcription factor NRF2 can regulate the transcription of a battery of antioxidant and detoxificant genes after heterodimerizing with small-Maf proteins. Although the participation of NRF2 in the development of chronic degenerative diseases has been thoroughly studied, the role of small-Maf genes has not been documented. We have identified polymorphisms in the three MAF genes (F, G and K) and assessed their association with CML. Over 266 subjects with CML and 399 unrelated healthy donors have been studied. After sequencing each MAF gene by Sanger technology, we found 17 variants in MAFF gene, eight in MAFG and seven in MAFK. In the case-control study, the homozygote genotype CC for the rs9610915 SNP of MAFF was significantly associated with CML. The frequency of the ACC haplotype from MAFK was significantly lower than controls. After stratification by gender, the ACC and GTG haplotypes were associated only with males with CML. These novel data suggest an association between MAFF and MAFG and the development of CML.