Iron may be implicated in the generation of oxidative stress by the catalyzing the Haber–Weiss or Fenton reaction. On the other hand, oxidative stress has been implicated in the pathogenesis of age-related macular degeneration (AMD) and heme oxygenase-1 (HO-1), encoded by the HMOX1 gene and heme oxygenase-2 (HO-2), encoded by the HMOX2 gene are important markers of iron-related oxidative stress and its consequences. Therefore, variability of the HMOX1 and HMOX2 genes might be implicated in the pathogenesis of AMD through the modulation of the cellular reaction to oxidative stress. In the present work, we investigated the association between AMD and a G → C transversion at the 19 position in the HMOX1 gene (the 19G>C-HMOX1 polymorphism, rs2071747) and a A → G transition at the −42 + 1444 position in the HMOX2 gene (the −42 + 1444A>G-HMOX2 polymorphism, rs2270363) and its modulation by some environmental factors. 279 patients with AMD and 105 controls were recruited in this study and the polymorphisms were typed by restriction fragment length polymorphism and allele-specific polymerase chain reaction (PCR). We observed an association between the occurrence of dry AMD and the G/A genotype of the −42 + 1444A>G-HMOX2 polymorphism (odds ratio (OR) 2.72), whereas the G/G genotype reduced the risk of dry AMD (OR 0.41). The G/C genotype and the C allele of the 19 G>C-HMOX1 polymorphism and the G/G genotype and the G allele of the −42 + 1444A>G-HMOX2 polymorphism were associated with progression of AMD from dry to wet form (OR 4.83, 5.20, 2.55, 1.69, respectively). On the other hand, the G/G genotype and the G allele of the 19 G>C-HMOX1 polymorphism and the A/G genotype and the A allele of the −42 + 1444A>G-HMOX2 polymorphism protected against AMD progression (OR 0.19, 0.19, 0.34, 0.59, respectively). Therefore, the 19G>C-HMOX1 and the −42 + 1444A>G-HMOX2 polymorphisms may be associated with the occurrence and progression of AMD.Electronic supplementary materialThe online version of this article (doi:10.1007/s11033-011-0955-3) contains supplementary material, which is available to authorized users.
Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, characterized by a peak of incidence between 2 and 5 years. Since recently conducted genome-wide association (GWA) studies revealed that the common low-penetrance susceptibility allele at 7p12.2 (IKZF1 gene) confers an increased risk of pediatric ALL, we investigated whether the risk allele at rs4132601 also coexists with well-established prognostic factors, among 508 Polish pediatric patients with newly diagnosed ALL. Additionally, to verify whether the risk allele is favored by somatic tumor evolution, we examined the incidence of IKZF1 deletions in leukemic clones derived from 153 previously genotyped cases of pediatric ALL. Results of the analysis provide statistically significant support for an association between the rs4132601 polymorphic site and age at diagnosis of childhood ALL (p = 0.04). No association between allele variant and occurrence of IKZF1 deletions was found. These data provide further evidence of a biological role of gene variants in the development of ALL.
SummaryBackgroundAge-related macular degeneration (AMD) is a primary cause of blindness among the elderly in developed countries. The nature of AMD is complex and includes both environmental and hereditary factors. Oxidative stress is thought to be essential in AMD pathogenesis. Iron is suggested to be implicated in the pathogenesis of AMD through the catalysis of the production of reactive oxygen species, which can damage the retina. Heme oxygenase-2 is capable of degradation of heme producing free iron ions, thus, diversity in heme oxygenase-2 gene may contribute to AMD. In the present work we analyzed the association between the c.544G>A polymorphism of the heme oxygenase-2 gene (HMOX2) (rs1051308) and AMD.Material/MethodsThis study enrolled 276 AMD patients and 105 sex- and age-matched controls. Genotyping of the polymorphism was performed with restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR) on DNA isolated from peripheral blood.ResultsWe did not find any association between the genotypes of the c.544G>A polymorphism and the occurrence of AMD. This lack of association was independent of potential AMD risk factors: tobacco smoking, sex and age. Moreover, we did not find any association between AMD and smoking in our study population.ConclusionsThe results suggest that the c.544G>A polymorphism of the heme oxygenase-2 gene is not associated with AMD in this Polish subpopulation.
Introduction The human leucocyte antigen-G (HLA-G) is a nonclassical class Ib molecule that suppresses various immune cell functions and may contribute to immune escape and cancer development. HLA-G polymorphisms, especially HLA-G-725(C/G/T) 5’URR and HLA-G 14bp del/ins 3’UTR, might influence the expression of HLA-G transcript and protein, and in consequence, affect the biological features of HLA-G. Therefore, we investigated whether these two polymorphisms, which seem to be functionally relevant, may play a role in susceptibility to chronic lymphocytic leukemia (CLL) and a clinical course of the disease. So far, no studies have reported any potentially impact of HLA-G polymorphisms on lymphoid neoplasms. Methods HLA-G725(C/G/T) 5’URR and HLA-G 14bp del/ins 3’UTR polymorphisms were genotyped in 167 previously untreated patients with CLL. The control group consisted of 98 randomly selected blood donors. Results Strong linkage disequilibrium between HLA-G-725(C/G/T) and HLA-G 14 bp del/ins was observed (D’=1.0 and r2=0.2). Six distinct haplotypes, including G/del, C/del, T/del, G/ins, C/ins, T/ins were found in the CLL patients. Among the controls only five haplotypes were found due to the T/ins haplotype not being observed. The probability of the occurrence of G/ins and T/ins haplotypes was higher in the CLL than in the controls (p= 0.01). The analysis of the prognostic significance of diplotypes, as well as the previously reported correlations between HLA-G genotypes and HLA-G expression in vitro and in vivo, allowed us to identify the HLA-G diplotype-based risk groups. The low-risk (LR) group comprised CC/del-del, CC/del-ins and CC/ins-ins diplotypes, and the high risk (HR) group included GG/del-del, GG/del-ins, GG/ins-ins, GC/del-del, GC/del-ins, GC/ins-ins, TT/del-del, TT/del-ins, TT/ins-ins and CT/del-ins diplotypes. The patients carrying LR diplotypes presented a higher 3-year treatment-free survival (TFS) (56.7%, 95% CI 47-66) than those with HR diplotypes (38.6%, 95% CI 27-52; p= 0.005). Additionally in the group of mutated IGHV patients, subjects carrying LR diplotypes presented a higher probability of 3-year TFS than those with HR diplotypes (68.5% vs 43.2%; p= 0.04). In regard to overall survival (OS), the estimated 5-year OS rates were 95.6% (95% CI 89-98) and 74.2% (95% CI 57-86) in the LR and HR group respectively (p= 0.005). Moreover, among the unmutated IGHV patients, those carrying LR diplotypes had a better 5-year OS compared to the patients with HR diplotypes (87.1% vs 71%; p= 0.02). Multivariate analysis demonstrated the IGHV mutation status (p= 0.005) and HLA-G diplotype-based risk groups (p= 0.01) to be independent factors predicting OS. Conclusions The results suggest the potential role of HLA-G and its polymorphisms in CLL. The inherited ability of the host to increase expression of the HLA-G antigen might contribute to the escape of CLL cells of the immuno-surveillance of the host and in turn to disease progression and the worse outcome for patients with CLL. Disclosures: No relevant conflicts of interest to declare.
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