The types and frequencies of X chromosome abnormalities in women with reproductive problems.

X chromosome architecture and integrity are essential for normal ovarian function. Both numerical and structural X chromosome abnormalities play an important role in female infertility. This study aims to determine the types and frequency of X chromosome aberrations detected in women referred for cytogenetic investigation due to reproductive problems. 2936 women (average age: 37.5 years) were enrolled in the present study. Peripheral blood karyotyping was performed by conventional cytogenetic techniques. For each woman, 20 G-banded metaphases were studied and in case of suspected mosaicism, analysis was extended to 100 metaphases. 2588/2936 (88.15%) of women had a normal karyotype (46,XX), while 348/2936 (11.85%) had an abnormal one. Thirty-two women (1.09%) carried autosomal chromosome abnormalities and 316 (10.76%) had X chromosome rearrangements. In 311/2936 women (10.59%) X chromosome numerical aberrations were detected (low-level mosaicism) and in 5/2936 cases (0.17%) X structural abnormalities (two with pericentric inversion, one with Xq deletion and two 45,X mosaics, one with an Xp deletion cell line and the other with isochromosome Xq cell line). Low-level X mosaicism was a common finding in women > 35 years, as compared to younger ones (92.93% vs 7.07%), a finding consistent with loss of chromosome X with ageing. Other X chromosome abnormalities were detected in younger women (32.3 ± 4.13 vs. 41.04 ± 4.5 years). The mean age of women with Turner-like phenotype was 28.75 ± 6.6 years. The study confirms that the incidence of X chromosome abnormalities is increased in women with fertility problems and that karyotype is the gold standard for their identification. Genetic counselling is recommended in these cases to provide information concerning available treatment and fertility options.

A 46,XX Karyotype in Men with Infertility: Two New Cases and Review of the Literature.

46,XX male sex reversal syndrome is a rare genetic cause of male infertility. We report on two new cases of this syndrome in men presenting with hypogonadism and infertility. Cytogenetic and molecular analysis was performed in both patients. An extensive review of the literature for 46,XX male sex reversal syndrome cases related to infertility was also performed to fully characterise this syndrome. Genetic analyses showed translocation of the SRY on Xp chromosome and complete absence of all Azoospermia factor (AZF) genetic regions. All patients included in the review presented hypergonadotropic hypogonadism. Small testes were the most common clinical characteristic present in 90.2% of the patients, followed by small penis (31.8%), gynecomastia (26.8%) and poor hair distribution (15.4%). The presence of the SRY was identified in 130/154 (84.4%) patients: in 98.5% of cases, it was translocated on the Xp chromosome and in 1.5% on an autosome. All patients were azoospermic, due to the lack of AZF genetic regions. Males with normal phenotype and primary hypogonadism should be properly evaluated by the physicians and must be referred for cytogenetic and molecular analysis to exclude or confirm 46,XX male sex reversal syndrome. More cases of this syndrome with SRY translocated on an autosome are needed to identify if these patients have different characteristics than those with SRY translocated on Xp chromosome. Whole genome analysis of these patients is required to elucidate the genetic differences which are responsible for the phenotypic variability of the syndrome.

Cytogenetic findings of ectopic endometriotic tissue in women with endometriosis and review of the literature.

OBJECTIVE: To determine chromosome and gene alterations in ectopic endometrial (EM) tissue which may be implicated in the clinical course or the progression of endometriosis and to review the literature concerning the cytogenetic findings of women with endometriosis. STUDY DESIGN: 15 women who underwent laparoscopic endometriosis surgery at the Athens Genesis Clinic were enrolled in the study. Ectopic endometrial tissue was surgically removed and further analyzed by conventional and molecular cytogenetic techniques. Fluoresent in situ hibridization (FISH) with probes for p53, ATM, MYC, MLL1 and IGH genes, the centromeres of chromosomes 7 and 8 and 7q22/7q31 chromosomal regions was carried out. RESULTS: Karyotypic analysis revealed no clonal chromosomal abnormalities. However, an increased frequency of polyploidy (55.6%) and sporadic chromosomal abnormalities (40.0%) concerning chromosomes 9, 11, 17 and X were noticed involving mainly deletions, trisomies or monosomies. FISH analysis showed IGH gene rearrangements in 54% of the EM cases and MLL gene rearrangements in 73% of the examined samples. Normal hybridization patterns were observed for p53, ATM and MYC. The increased frequency of polyploidy shown by conventional karyotyping was also confirmed by FISH. CONCLUSION: Polyploidy, sporadic chromosomal abnormalities, as well as IGH and MLL gene rearrangements, may provoke genetic instability and play a potential role in the development of endometriosis. IGH and MLL gene rearrangements indicate a genetic relation between endometriosis and carcinogenesis. Confirmation of the above gene rearrangements in a large series of women may allow the determination of their possible involvement in the pathogenesis of this complex disease and their possible contribution in the early identification of women in danger for malignant transformation.

Detection of a novel unbalanced X;21 translocation in a girl with Turner syndrome phenotype.

OBJECTIVE: To describe a novel unbalanced X;21 translocation resulting in a derivative pseudodicentric chromosome X;21 lacking the critical region for ovarian development and function, in a 16-year-old girl referred for cytogenetic analysis due to primary amenorrhea and Turner-like features. METHODS: Cytogenetic analysis of the proband and her parents was performed on peripheral blood lymphocytes by GTG banding. Molecular cytogenetic FISH analysis was performed on metaphase preparations, using X chromosome centromeric probe and telomeric and pancentromeric peptide nucleic acid (PNA) analog probes. The HUMARA assay as well as methylation studies for PCSK1N and FMR-1 loci were performed. RESULTS: Cytogenetic analysis revealed a de novo unbalanced X;21 translocation, described as 45,X,der(X)t(X;21)(q22.2;p11.2),-21. FISH analysis showed that the derivative X chromosome carried both the X and 21 centromeres, as well as, the Xp and 21q telomeres. The karyotype was thus reevaluated as 45,X,psu dic(21;X)(21qter→21p13::Xq22.2→Xpter),-21. X inactivation studies revealed that the derivative chromosome was of paternal origin and confirmed the selective inactivation of the derivative X segment of the pseudodicentric chromosome. CONCLUSIONS: Primary amenorrhea and other Turner-like characteristics of the proband are apparently due to the loss of the Xq22.2→Xqter critical region which contains critical genes for the ovarian development and function. The chromosome X segment of the derivative pseudodicentric chromosome is selectively inactivated, but inactivation does not seem to spread onto the translocated chromosome 21, accounting probably for the lack of severe clinical consequences which would result from monosomy 21.

Perinatal lipocalin-2 profile at the extremes of fetal growth.

BACKGROUND: Lipocalin-2 (LCN-2) has been identified as an osteoblast-secreted hormone regulating immunity, inflammation and metabolic homeostasis and has emerged as a diagnostic and prognostic biomarker for acute kidney injury in neonates. We investigated the impact of fetal growth on antepartum maternal serum, cord serum and breast milk LCN-2 concentrations and the associations of the latter with perinatal parameters. METHODS: Maternal serum, cord serum and breast milk LCN-2 concentrations were measured by ELISA in samples from 80 mothers who delivered 40 appropriate (AGA), 20 large for gestational age (LGA) and 20 intrauterine growth restricted (IUGR) neonates, classified by customized weight centiles. LCN-2 concentrations were associated with birth weight, customized centile, gender, maternal age and delivery mode. RESULTS: Antepartum maternal serum LCN-2 concentrations were significantly higher in women delivering AGA infants compared to the other two groups. Cord blood LCN-2 concentrations were significantly higher compared to maternal ones; furthermore, they were significantly elevated in the IUGR group compared to the LGA one (p = .019). Lowest concentrations were detected in breast milk, which did not differ between the three growth groups. A negative correlation was documented between cord blood LCN-2 concentrations and customized centiles (r: -0.304, p = .007). CONCLUSIONS: The higher cord serum LCN-2 concentrations, compared to maternal ones, may point to its fetal origin and potential role in intrauterine growth. The negative correlation of cord LCN-2 concentrations with customized centiles, possibly implies reduced nephron endowment/subclinical kidney damage in IUGR neonates. The extremely low LCN-2 breast milk concentrations could imply that the secretion of LCN-2 from maternal circulation to breast milk is not influenced by factors leading to intrauterine growth pathology.

Female Reproductive Ageing and Chromosomal Abnormalities in a Large Series of Women Undergoing IVF.

Chromosomal abnormalities are often detected in women with reproductive problems. This study aimed to investigate the presence and type of chromosomal aberrations in peripheral blood of women undergoing in vitro fertilization (IVF) and their possible association with advanced maternal age (AMA). A total of 1,837 women undergoing IVF between 2016 and 2019 were enrolled in the study. Women were further divided in AMA (≥35 years) and younger women (<35 years). Chromosomal abnormalities were detected by peripheral blood karyotyping using standard cytogenetic techniques. Chromosomal abnormalities were detected in 13.5% of the enrolled women; 1.1% had autosomal abnormalities including reciprocal translocations, inversions, Robertsonian translocations, and a supernumerary marker chromosome, while 12.4% had X chromosome abnormalities. The frequency of chromosomal abnormalities was significantly higher in AMA women than in younger ones (17.4% vs. 3.9%, p < 0.05). Women of AMA exhibited X chromosome mosaicism with a frequency of 16.1%, and mosaic karyotypes with 2 and 3 aneuploid cell lines were more frequently detected. X chromosome mosaicism is the most common karyotypic aberration in women undergoing IVF and has 6-fold increased incidence in AMA women compared to younger ones. The present study verifies previous observations that low-level peripheral blood X chromosome mosaicism and the number of aneuploid cell lines observed in women of AMA could be an indication of aneuploidy and poor quality of oocytes contributing to infertility.

Low-level X Chromosome Mosaicism: A Common Finding in Women Undergoing IVF.

BACKGROUND/AIM: To determine the incidence of X chromosome mosaicism in women undergoing in vitro fertilization (IVF) treatment and present preimplantation genetic testing for aneuploidy (PGT-A) outcome of this group. PATIENTS AND METHODS: A total of 1,058 women undergoing IVF and 154 women with no fertility problems were enrolled in the study. Karyotyping from peripheral blood lymphocytes was performed by conventional cytogenetics. Twenty-nine women with X mosaicism underwent PGT-A by array-comparative genomic hybridization from embryos at the blastocyst stage. RESULTS AND CONCLUSION: Out of 1,058 women undergoing IVF, 166 (15.7%) had an abnormal karyotype. The most common finding (14.6%) was X chromosome mosaicism. Its frequency was higher in women >35 years old and reached 46.1% in those >45 years of age. PGT-A results of 130 blastocysts tested showed that 29/117 (24.8%) were euploid; 17/29 (60%) were transferred and 10/17 (70%) were successfully implanted, indicating that PGT-A may be an option for women with low-level X chromosome mosaicism undergoing IVF in order to improve the likelihood of a successful pregnancy outcome.

I-131 Postablation SPECT/CT Predicts Relapse of Papillary Thyroid Carcinoma more Accurately than Whole Body Scan.

BACKGROUND/AIM: The aim of the study was to prospectively compare I-131 postablation Whole Body scan (WBS) and Single Photon Emission Computerized Tomography/Computerized Tomography (SPECT/CT) scan on thyroid cancer patients. PATIENTS AND METHODS: Overall, 58 patients with papillary thyroid carcinoma were submitted to total thyroidectomy and I-131 remnant ablation. Post-ablation WBS and SPECT/CT scans performed on the same day were compared. Results of SPECT/CT were confirmed by neck and upper mediastinum ultrasound scan and on specific cases by a fully diagnostic CT scan, other tests and definitive histology acting as the gold standard. A total of 36/58 patients were followed-up for 5 years to detect relapse. RESULTS: Mac Nemar Chi square and Fisher's exact tests disclosed statistically significant differences between WBS and SPECT/CT scan, concerning cervical lymphadenopathy detection (p=0.031) and relapse prediction by NM stage (p=0.033), respectively; SPECT/CT was more accurate in both comparisons. CONCLUSION: In papillary thyroid carcinoma I-131 post-ablation SPECT/CT scan detects cervical lymphadenopathy and predicts relapse by NM stage more accurately than WBS.

Paraoxonase 1 (PON1) Q192R and L55M Polymorphisms as Potential Predisposition Factors for Chronic Lymphocytic Leukemia.

BACKGROUND/AIM: PON1 gene has an executive role in antioxidant defense, protecting cells from genotoxic factors. Q192R and L55M PON1 polymorphisms reduce catalytic activity of the encoded protein. These polymorphisms were studied in 300 chronic lymphocytic leukemia (CLL) patients and 106 healthy donors. They were also associated with patients' cytogenetic findings, to investigate their possible implication in CLL pathogenesis. MATERIALS AND METHODS: SNP genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Karyotypic analysis was also performed by chromosome G-banding analysis and fluorescence in situ hybridization. RESULTS: Genotypic and allelic distribution of Q192R polymorphism showed a statistically significant higher frequency of mutant genotypes and mutant alleles in patients compared to controls. The same observation was noted in patients with abnormal karyotypes and those carrying abn14q32 and del(6q). A statistically increased frequency for the mutant allele was also revealed in patients with del(11q). On the contrary, L55M polymorphism showed a similar distribution between patients and controls. CONCLUSION: Q192R polymorphism plays a role in CLL predisposition and the formation of specific chromosomal aberrations.

Cohesin RAD21 Gene Promoter Methylation in Patients with Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in adults and is characterized by the presence of specific cytogenetic abnormalities. CLL research has been focused on epigenetic processes like gene promoter methylation of CpG islands. In the present study, the methylation status of the RAD21 gene is studied and associated with cytogenetic findings in CLL patients in order to investigate its possible implication in CLL pathogenesis and the formation of CLL chromosomal abnormalities.

GSTP1 and CYP2B6 Genetic Polymorphisms and the Risk of Bronchopulmonary Dysplasia in Preterm Neonates.

Objectives Antioxidant response plays a key role in bronchopulmonary dysplasia (BPD) pathogenesis. The glutathione-S-tranferases pi 1 (GSTP1) and cytochrome P450 (CYP) detoxification enzymes protect cells from oxidative damage. The aim of the study was to investigate whether the A313G GSTP1 and G516T CYP2B6 inactivating polymorphisms could be associated with BPD susceptibility. Study Design To test this hypothesis, we conducted a case-control study enrolled 138 premature neonates ≤32 weeks of gestational age; of the 138, 46 developed BPD and 92 did not develop BPD. Genomic deoxyribonucleic acid was extracted from neonates' peripheral blood and was used as template for GSTP1 and CYP2B6 genotyping using the real-time polymerase chain reaction method. Results Our report provides evidence for a possible pathogenetic role of the G516T CYP2B6 polymorphism in BPD susceptibility. Although no differences in the frequencies of the GSTP1 variant genotypes were noticed between premature neonates who developed BPD and neonates who did not develop BPD, a significantly higher frequency of the GSTP1 polymorphism was observed in extremely low birth weight infants. Despite the small sample size, it is very interesting the fact that all neonates ≤1,000 g carrying the homozygous mutant GSTP1 genotype developed BPD. Conclusion Our results underscore the significance of both CYP2B6 and GSTP1 polymorphisms in modulating the risk of BPD.

Possible Implication of GSTP1 and NQO1 Polymorphisms on Natalizumab Response in Multiple Sclerosis.

Oxidative stress plays a pivotal role in the pathogenesis of multiple sclerosis (MS). Inactivating polymorphism of genes encoding detoxification enzymes, such as NQO1 and GSTP1 could influence susceptibility to MS. The monoclonal antibody natalizumab is an effective treatment in MS. Natalizumab's efficacy in MS patients with regard to NQO1 and GSTP1 genetic polymorphisms is investigated. 130 patients with definite MS according to the Mc Donald's criteria treated monthly with natalizumab were included in the study. MS patients were classified with regard to their clinical subtype, gender and clinical outcome after Natalizumab administration. GSTP1 and NQO1 genotyping was performed using Real-Time PCR and PCR-RFLP assays. Among our cohort of MS patients, 88.5% responded and 11.5% manifested clinical deterioration after natalizumab treatment. Statistical analysis revealed a significantly increased frequency of double NQO1 and GSTP1 mutant polymorphisms in non responders compared to the responders. Therefore, patients who carry the wild type genotype or only one polymorphism for either NQO1 or GSTP1 gene have possibly a better clinical outcome after the natalizumab therapy. Our findings indicate that antioxidant efficiency might reflect a better clinical outcome after natalizumab administration. Hence, oxidative stress reduction might be another mechanism through which natalizumab exerts its protective effect.

Polymorphisms and haplotypes of the CYP2B6 detoxification gene in the predisposition of Acute Myeloid Leukemia (AML) and induction of its cytogenetic abnormalities.

CYP2B6 is a polymorphic detoxification gene which plays a vital role in the degradation of genotoxic compounds. In this study we hypothesized that inadequate detoxification due to CYP2B6 polymorphisms may contribute to AML. To evaluate the potential impact of CYP2B6 polymorphisms on AML development and induction of its specific chromosomal abnormalities we studied C777A and A785G polymorphisms for the first time in AML. Furthermore, we investigated the co-existence of the above polymorphisms with G516T polymorphism to determine the CYP2B6 high-risk haplotypes in AML susceptibility. Our study included 619 AML patients and 430 healthy donors. Concerning C777A CYP2B6 polymorphism, no significant difference was found between patients and controls. However, A785G CYP2B6 polymorphism showed a statistically higher frequency of the variant genotypes in patients (48.2%), mainly in secondary AML patients (49.1%) than in controls (26.1%). Moreover, an increased frequency of the variant genotypes was found in those with abnormal karyotypes, especially with -7/del(7q), -5/del(5q), +8, inv(16) and t(8;21). The combination of the three CYP2B6 polymorphisms (G516T, C777A & A785G) revealed seven haplotypes. Four out of six haplotypes with at least one mutant allele were significantly associated with an increased risk for AML. Interestingly, T516A777G785 haplotype, where the three mutant alleles co-existed, had ~3-fold increased risk to be found in patients than controls. The association between haplotypes and cytogenetic aberrations revealed a positive correlation between specific CYP2B6 haplotypes and AML cytogenetic abnormalities. Our data suggest that A785G CYP2B6 gene polymorphism and specific CYP2B6 haplotypes may contribute to AML and its specific chromosomal aberrations.

Association of C609T-Inborn Polymorphism of NAD(P)H: Quinone Oxidoreductase 1 with the Risk of Bronchopulmonary Dysplasia in Preterm Neonates.

UNLABELLED: Objectives In bronchopulmonary dysplasia (BPD), direct exposure to oxygen therapy can damage the pulmonary epithelium via oxidative stress. The NAD(P)H: quinone oxidoreductase 1 (NQO1) enzyme detoxifies genotoxic products of oxidative stress. The corresponding gene is subject to an inactivating single-nucleotide polymorphism (C(609)T), which reduces detoxifying ability. The aim of this study was to investigate whether the C(609)T NQO1 inborn gene polymorphism is associated with an increased risk of BPD. Study Design Peripheral blood samples from 119 premature neonates ≤ 32 weeks of gestational age (42 BPD and 77 non-BPD) were used for DNA extraction. NQO1 genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. Results A significantly higher frequency of the NQO1 polymorphism was observed in BPD neonates compared with neonates without BPD. All neonates with ≤ 1,000 g birth weight who carried the mutant allele in heterozygous or homozygous state developed BPD. None of the BPD nonaffected group neonates with ≤ 1,000 g birth weight carried the NQO1 polymorphism. Conclusion The higher incidence of NQO1 mutants among BPD neonates as well as the presence of the mutant allele in all neonates with ≤ 1,000 g who developed BPD provided the first evidence for a possible pathogenetic role of the C(609)T polymorphism in BPD susceptibility due to the reduction or loss of NQO1 enzymatic activity.

Comparison of Bacterial Community Composition of Primary and Persistent Endodontic Infections Using Pyrosequencing.

INTRODUCTION: Elucidating the microbial ecology of endodontic infections (EIs) is a necessary step in developing effective intracanal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population using high-throughput sequencing methods. METHODS: 16S amplicon pyrosequencing of 48 root canal bacterial samples was conducted, and sequencing data were analyzed using an oral microbiome-specific and a generic (Greengenes) database. Bacterial abundance and diversity were examined by EI type (primary or persistent), and statistical analysis was performed by using non-parametric and parametric tests accounting for clustered data. RESULTS: Bacteroidetes was the most abundant phylum in both infection groups. Significant, albeit weak associations of bacterial diversity were found, as measured by UniFrac distances with infection type (analyses of similarity, R = 0.087, P = .005) and symptoms (analyses of similarity, R = 0.055, P = .047). Persistent infections were significantly enriched for Proteobacteria and Tenericutes compared with primary ones; at the genus level, significant differences were noted for 14 taxa, including increased enrichment of persistent infections for Lactobacillus, Streptococcus, and Sphingomonas. More but less abundant phyla were identified using the Greengenes database; among those, Cyanobacteria (0.018%) and Acidobacteria (0.007%) were significantly enriched among persistent infections. Persistent infections showed higher phylogenetic diversity (PD) (asymptomatic: PD = 9.2, standard error [SE] = 1.3; symptomatic: PD = 8.2, SE = 0.7) compared with primary infections (asymptomatic: PD = 5.9, SE = 0.8; symptomatic: PD = 7.4, SE = 1.0). CONCLUSIONS: The present study revealed a high bacterial diversity of EI and suggests that persistent infections may have more diverse bacterial communities than primary infections.

Combined GSTP1 and NQO1 germline polymorphisms in the susceptibility to Multiple Sclerosis.

Germline polymorphisms of detoxification genes could influence susceptibility to Multiple Sclerosis (MS). Glutathione-S-transferases (GSTs) and NAD(P)H: quinone oxidoreductase 1 (NQO1) are detoxifying enzymes involved in biotransformation of metabolites preventing cells from oxidative damage. In order to evaluate the possible contribution of the A313G GSTP1 inactivating polymorphism, alone and in combination with the C609T NQO1 genetic variant in MS susceptibility, we performed a case-control study consisting of 254 MS patients and 370 healthy donors. Genotypes were investigated using a new Real-Time PCR and PCR-RFLP assays. The GSTP1 polymorphism was evaluated in relation to patients' characteristics (clinical subtypes, age and gender) and the NQO1 gene status. GSTP1 genotype distribution was similar between cases and controls. Higher frequency of GSTP1 heterozygotes was observed in patients with relapsing remitting disease (RRMS) (p = 0.019), especially in those presenting a benign form (EDSS ≤ 2 after 10-15 years from the disease onset). Interestingly, genotype distribution analysis of combined GSTP1 and NQO1 polymorphisms revealed significantly higher frequency of GSTP1 heterozygous (A/G) and NQO1 variant genotypes (C/T and T/T) in patients as compared to the controls (p = 0.031). The increased incidence of combined GSTP1 and NQO1 variant genotypes in MS patients may suggest that defective function of detoxification enzymes might be an important determinant of susceptibility and clinical manifestation of the disease. Moreover, the results suggest a possible role for the GSTP1 heterozygous background in the development of RRMS.

The G5¹6T CYP2B6 germline polymorphism affects the risk of acute myeloid leukemia and is associated with specific chromosomal abnormalities.

The etiology of acute myeloid leukemia (AML) underlies the influence of genetic variants in candidate genes. The CYP2B6 enzyme detoxifies many genotoxic xenobiotics, protecting cells from oxidative damage. The CYP2B6 gene is subjected to a single-nucleotide polymorphism (G5¹6T) with heterozygotes (GT) and homozygotes (TT) presenting decreased enzymatic activity. This case-control study aimed to investigate the association of CYP2B6 G5¹6T polymorphism with the susceptibility of AML and its cytogenetic and clinical characteristics. Genotyping was performed on 619 AML patients and 430 healthy individuals using RCR-RFLP and a novel LightSNip assay. The major finding was a statistically higher frequency of the variant genotypes (GT and TT) in patients compared to the controls (GT:38.8% vs 29.8% and TT:9.3% vs 5.3% respectively) (p<0.001). More specifically, a significantly higher frequency of GT+TT genotypes in de novo AML patients (46.6%) and an immensely high frequency of TT in secondary AML (s-AML) (20.5%) were observed. The statistical analysis showed that the variant T allele was approximately 1.5-fold and 2.4-fold higher in de novo and s-AML respectively than controls. Concerning FAB subtypes, the T allele presented an almost 2-fold increased in AML-M2. Interestingly, a higher incidence of the TT genotype was observed in patients with abnormal karyotypes. In particular, positive correlations of the mutant allele were found in patients carrying specific chromosomal aberrations [-7/del(7q), -5/del(5q), +8, +21 or t(8;21)], complex or monosomal karyotypes. Finally, a strikingly higher frequency of TT genotype was also observed in patients stratified to the poor risk group. In conclusion, our results provide evidence for the involvement of the CYP2B6 polymorphism in AML susceptibility and suggest a possible role of the CYP2B6 genetic background on the development of specific chromosomal aberrations.

High frequency of NAD(P)H:quinone oxidoreductase 1 (NQO1) C(609)T germline polymorphism in MDS/AML with trisomy 8.

The NQO1 C(609)T germline polymorphism resulting in a lowering of enzyme activity may confer susceptibility to MDS. To assess this association, we performed a case-control study including 330 Greek patients with de novo MDS and 416 healthy donors, using a Real-Time PCR genotyping method. Focusing on cytogenetic aberrations most commonly found in MDS, we retrospectively genotyped 566 MDS/AML patients carrying -5/del(5q), -7/del(7q), +8, del(20q) and -Y. The case-control analysis revealed no differences in NQO1 genotype distribution. Interestingly, a 6-fold increased frequency of the homozygous variant genotype was observed among patients with isolated trisomy 8 (p<0.0001), suggesting that null NQO1 activity may influence the occurrence of +8 in MDS/AML.