Héctor Montoya-Fuentes

Genetic polymorphisms of the renin-angiotensin system in preterm delivery and premature rupture of membranes

Introduction. Premature rupture of membranes (PRM) is a late pregnancy complication commonly associated with preterm delivery (PD).Although several markers related to the renin-angiotensin system (RAS) have been evaluated in certain pregnancy complications, only the angiotensin-converting enzyme (ACE) I/D variant has been studied in PD-PRM.The aim of this survey was to investigate the association of the polymorphisms (angiotensin II type 1 [AT1] receptor T174M and M235T, renin G2805A,ACE I/D and AT1-receptor A1166C) of the genes of RAS in women with PD-PRM. Design. Deoxyribonucleic acid samples from 89 Mexican Mestizo women with PD and PRM and 224—288 controls were studied. Polymorphisms were analysed by polymerase chain reaction-sequence specific primer assays. restricted fragment length polymorphism or sequence specific prim assays. Results. For all loci , genotype distribution was in agreement with Hardy—Weinberg expectations in the control group. Significant intergroup difference (case vs. control) was seen for angiotensinogen (AGT) M235T polymorphism, with an increased allele M235 in affected cases (50% vs. 40% in controls).Analysis of two-locus haplotype agrees with an independent segregation of physically unlinked genes. Haplotype AGT 174T-235M was also increased (50 % vs. 40% in controls). Conclusions. Physically unlinked genes involved in RAS segregate independently. The AGT 174—235 region is associated with PD-PRM in this population.

Presence of HPV DNA in placenta and cervix of pregnant Mexican women.

PurposeTo identify the presence of HPV DNA in cervical as well as in placental tissue of pregnant Mexican women and to determine which type is more frequent.MethodsIn a cross-sectional study, 56 placental samples were obtained from 72 pregnant women. HPV DNA was extracted and amplified with polymerase chain reaction using a consensus primer and then identified by type using RsaI endonuclease. The main outcome measures were placenta with/without HPV relation and HPV types in placenta.ResultsHPV DNA was identified in 75% of cervical tissue samples and 47.2% of placental tissue samples. Type 18 was the most frequently identified HPV type.ConclusionsThere was a higher frequency of HPV DNA found in the cervix of Mexican women during pregnancy than reported in the previous studies. Its identification in full-term placental tissue has no relation to the type of delivery in childbirth.

Renin gene haplotype diversity and linkage disequilibrium in two Mexican and one German population samples

Introduction. Renin is the main rate-limiting enzyme in the renin—angiotensin—aldosterone system. Its gene, REN, is a candidate crucial factor in essential hypertension and cardiovascular disease. The aim of this study was to evaluate allele and haplotype distributions of REN polymorphisms, and to estimate normalised linkage disequilibrium (D’) in Mexican and German populations. Materials and methods. Four groups were studied for the REN single nucleotide polymorphisms (SNPs) 1205C>T, 1303G>A, and 10607G>A, in population samples of Mexican Mestizo (n = 86), Mexican Huichol (n = 49), German (n = 39), and individuals with hypertension diagnosis (n = 66). Polymorphisms were detected by PCR—RFLP. Genotype, allele and haplotype frequencies were estimated. Results. SNP 1205C>T and 10607G>A allele and genotype distribution showed inter-group differences. The 1205T and 10607A allele showed a significance difference in hypertensive population. Haplotype analysis also showed some inter-group differences, especially in 1205C-1303G-10607G, 1205C-1303G-10607A and 1205T-1303G-10607G haplotypes. The segregation analysis disclosed complete linkage disequilibrium between 1205 and 1303 loci. Conclusion. These results provide an example of genetic diversity in related populations and illustrate the convenience of increasing the number of loci in associative studies between diseases and candidate genes.

Association of RETN and CAP1 SNPs, Expression and Serum Resistin Levels with Breast Cancer in Mexican Women

BACKGROUND Breast cancer is the most common cancer in women worldwide. Approximately 70% of female breast cancer patients have a body mass index (BMI) >25. In obesity, adipose tissue secretes additional resistin, which prompts a proinflammatory effect through its action on adenylate cyclase-associated protein 1 (CAP1). Several studies have associated the RETN gene single nucleotide polymorphism (SNP) rs1862513 (-420C<G) with serum resistin levels and breast cancer. The CAP1 gene SNP rs35749351 (missense, Arg294His), located in the extracellular domain, has not previously been studied in cancer. These two SNPs, the mRNA expression levels of the two alleles for each of the cognate genes, and the serum resistin levels were compared between patients and controls to determine their association with breast cancer in Mexican women in this study. MATERIALS AND METHODS This study included 308 controls and 100 female patients with breast cancer. SNPs were detected by PCR-RFLP from DNA isolated from peripheral blood. Gene expression was performed with hydrolysis probes in tumor tissue. Resistin levels were quantified from serum samples by ELISA. RESULTS The RETN rs1862513CG/GG and CAP1 rs35749351GA/AA genotypes were associated with 1.61 and 2.193-fold increased risks of breast cancer, respectively, compared with the CC and GG genotypes. Similarly, carriers of the G allele of rs1862513 and the A allele of rs35749351, had 1.51 and 2.217-fold increased risks of breast cancer compared with the C and G alleles, respectively. The rs1862513GG/rs35749351AA genotype combination increased breast cancer risk by twofold. Serum resistin levels in postmenopausal breast cancer women were higher compared with postmenopausal controls. Tissue CAP1 expression showed differences with regard to molecular subtypes and metastases. CONCLUSION The RETN and CAP1 polymorphisms and gene expression may be potential biomarkers for breast cancer risk.

Distribution of IFITM3 polymorphism (dbSNP: rs12252) in mestizo populations in four states of Mexico

Interferon‐inducible transmembrane protein 3 (IFITM3) participates in the defense against viral infections. This study identified and compared the frequency of the IFITM3 rs12252 polymorphism in 410 individuals in western Mexico. The western Mexican allelic frequencies (frequency of the “C” allele = 0.18) differ from some American, East Asian and European populations.

Association of the rs2279744 Promoter Polymorphism in the MDM2 Gene with Breast Cancer in a Mexican Population

Introduction: The MDM2 gene plays an important role as negative regulator of the p53 tumor suppressor. Data on polymorphisms in the MDM2 gene have revealed associations with cancer, particularly for the rs2279744 promoter polymorphism (309 T > G), which attenuates the P53 pathway and promotes tumorigenesis in the mammary gland. Material and Methods: We examined the role of the MDM2 309 T > G polymorphism through a comparison of the genotypes of 408 healthy Mexican women with those of 529 Mexican women with breast cancer (BC). Results: The genotype frequencies of the MDM2 309 T > G polymorphism in controls and BC patients were 25% and 23% for T/T (wild type), 50% in BC and controls for T/G, and 25 and 27% for G/G (polymorphic type), respectively. The obtained odds ratio (OR) was 1.07, with a 95% confidence interval (95% CI) of 0.79-1.45, p = 0.64 for the T/GG/ G genotypes. The association was evident when the distributions of the G/G genotypes in patients exhibiting the following characteristics were compared: breastfeeding >6 months (OR 2.1, 95% CI 1.3-3.4, p = 0.002), obesity (OR 1.8, 95% CI 1.2-2.7, p = 0.003) and high GGT levels (OR 1.7, 95% CI 1.1-2.5, p = 0.012). The genotype G/G of the MDM2 309 T > G. Conclusions: The MDM2 309 T > G polymorphism was associated with BC susceptibility, particularity in breastfeeding, obesity and high GGT levels in the analyzed Mexican population.