Outdoor air pollution exposures and micronuclei frequencies in lymphocytes from pregnant women and newborns in Crete, Greece (Rhea cohort).

BACKGROUND: Micronuclei (MN) are biomarkers of early genetic effects that have been used to investigate the association between environmental exposures and cancer. However, few studies have examined the association between environmental exposures during pregnancy and MN in mothers and newborns. OBJECTIVES: We examined MN frequency in maternal blood and in cord blood, in relation to maternal air pollution exposure, and the potential interaction with maternal vitamin C intake and maternal smoking. METHODS: We used the cytokinesis-block micronucleus assay to assess MN frequency per 1000 bi-nucleated T-lymphocytes from 181 mothers and 183 newborns born in 2007-2008 in Heraklion (Crete, Greece). The ESCAPE land-use regression methods were used to estimate annual mean exposure to outdoor air pollution [particulate matter (PM), black carbon, nitrogen dioxide (NO2) and nitrogen oxides (NOx)] at maternal home addresses. Food frequency questionnaires were used to estimate maternal dietary vitamin C intake during pregnancy. Smoking habits were self-reported using questionnaires which were checked by measuring maternal urinary cotinine levels. RESULTS: Exposure to PM2.5 was associated with increased MN frequencies in pregnant women [rate ratio [RR (95%CI)] per 5 µg/m(3)=1.53 (1.02, 2.29)]. This increase was considerably higher among women who did not fulfill the recommended vitamin C dietary allowances [RR=9.35 (2.77, 31.61); n=20]. Exposure to PM2.5-10, PM10, NO2 and NOx were also associated with a higher incidence of MN frequencies in smoker women (n=56). No associations were found for newborns. CONCLUSIONS: We found an association between air pollution, particularly PM2.5, and MN frequency in mothers but not in newborns. This association was more pronounced among women with a lower dietary intake of vitamin C during pregnancy and among women who smoked during pregnancy. While results are clear in mothers, the association between maternal carcinogenic exposures during pregnancy and biomarkers of early biologic effect in the newborn remains poorly understood.

The effect of dietary estimates calculated using food frequency questionnaires on micronuclei formation in European pregnant women: a NewGeneris study.

The use of biomarkers of early genetic effects, predictive for cancer, such as micronuclei (MN) in lymphocytes, may help to investigate the association between diet and cancer. We hypothesised that the presence of mutagens in the diet may increase MN formation. A 'pooled' standardised analysis was performed by applying the same experimental protocol for the cytokinesis block micronucleus assay in 625 young healthy women after delivery from five European study populations (Greece, Denmark, UK, Spain and Norway). We assessed MN frequencies in mono- and binucleated T-lymphocytes (MNMONO and MNBN) and the cytokinesis blocked proliferation index using a semi-automated image analysis system. Food frequency questionnaires (FFQs) were used to estimate intake of fatty acids and a broad range of immunotoxic and genotoxic/carcinogenic compounds through the diet. Pooled difference based on delivery type revealed higher MNMONO frequencies in caesarean than in vaginal delivery (P = 0.002). Statistical analysis showed a decrease in MNMONO frequencies with increasing calculated omega-6 PUFA concentrations and a decrease in MNBN frequencies with increasing calculated omega-3 PUFA concentrations. The expected toxic compounds estimated by FFQs were not associated with MN formation in mothers after delivery. In pregnant women, an omega-3 and -6 rich diet estimated by FFQ is associated with lower MN formation during pregnancy and delivery.

Validation of the nucleotide excision repair comet assay on cryopreserved PBMCs to measure inter-individual variation in DNA repair capacity.

Inter-individual susceptibility to mutagens/carcinogens can be assessed by either genotyping DNA repair genes in different pathways or phenotyping DNA repair capacity (DRC) at the molecular or cellular level. Due to the large number of known DNA repair genes, and the interactions between repair pathways, phenotyping is becoming the preferred approach to measure DRC, and reliable assays are therefore increasingly needed. The use of a cellular phenotype comet assay for the nucleotide excision repair (NER) pathway using benzo[a]pyrene diol epoxide (BPDE) has been described in previous papers, but no thorough evaluation of its applicability in large genotype-phenotype studies has been presented. Our aim was to evaluate the possibility of using cryopreserved instead of fresh peripheral blood mononuclear cells (PBMCs) to evaluate intra- and inter-assay variation, and inter-individual variation, for the aphidicolin (APC)-block NER comet assay. Moreover, we measured the variation for the designated internal standard (K562 erythroleukaemia cell line) and we evaluated the feasibility to use lymphoblastoid cell lines (LCLs) as surrogate of PBMCs. Our results showed a low intra-assay [coefficient of variation (CV) 19.9%] and inter-assay (CV 32.3%) variation, with a good inter-individual variation (122 subjects, mean ± standard deviation 7.38 ± 4.99; range 0.66-26.14; CV 67.63%). A significant correlation between results derived from cryopreserved and fresh PBMCs from the same individuals was found (10 subjects, r = 0.62, P = 0.05). Results from LCLs and cryopreserved PBMCs from the same subjects showed an inverse significant correlation (10 subjects, r = -0.712, P = 0.02). K562 cells as internal standard showed low intra-assay variation. In the present study the APC-block NER comet assay on cryopreserved PBMCs seemed to be a reliable method to measure DRC variation in epidemiological studies; LCLs were not a good surrogate in this assay.

Preterm newborns show slower repair of oxidative damage and paternal smoking associated DNA damage.

Newborns have to cope with hypoxia during delivery and a sudden increase in oxygen at birth. Oxygen will partly be released as reactive oxygen species having the potential to cause damage to DNA and proteins. In utero, increase of most (non)-enzymatic antioxidants occurs during last weeks of gestation, making preterm neonates probably more sensitive to oxidative stress. Moreover, it has been hypothesized that oxidative stress might be the common etiological factor for certain neonatal diseases in preterm infants. The aim of this study was to assess background DNA damage; in vitro H(2)O(2) induced oxidative DNA damage and repair capacity (residual DNA damage) in peripheral blood mononucleated cells from 25 preterm newborns and their mothers. In addition, demographic data were taken into account and repair capacity of preterm was compared with full-term newborns. Multivariate linear regression analysis revealed that preterm infants from smoking fathers have higher background DNA damage levels than those from non-smoking fathers, emphasizing the risk of paternal smoking behaviour for the progeny. Significantly higher residual DNA damage found after 15-min repair in preterm children compared to their mothers and higher residual DNA damage after 2 h compared to full-term newborns suggest a slower DNA repair capacity in preterm children. In comparison with preterm infants born by caesarean delivery, preterm infants born by vaginal delivery do repair more slowly the in vitro induced oxidative DNA damage. Final impact of passive smoking and of the slower DNA repair activity of preterm infants need to be confirmed in a larger study population combining transgenerational genetic and/or epigenetic effects, antioxidant levels, genotypes, repair enzyme efficiency/levels and infant morbidity.

Automated image analysis of micronuclei by IMSTAR for biomonitoring.

For many years, the analysis of micronuclei (MN) has been successfully applied to human biomonitoring of in vivo genotoxin exposure and provides a sensitive and relatively easy methodology to assess genomic instability. However, there is a need for automation of MN analysis for rapid, more reliable and non-subjective MN detection. In this review, we evaluate the application of automated image analysis of the in vitro cytokinesis-block MN assay on human lymphocytes for human biomonitoring, starting with the requirements that should be fulfilled by a valid and efficient image analysis system. Considering these prerequisites, we compare the automated facility developed in the framework of the European Union-project NewGeneris with other already published systems for automated scoring of MN. Although the automated scoring of MN is now put into place, extension to other cytome assay end points such as apoptosis, necrosis, nuclear buds and nucleoplasmic bridges would greatly enhance the specificity and sensitivity of future biomonitoring studies. Inclusion of these end points would also allow an automated approach to in vitro genotoxicity testing. In addition, automated scoring of the MN assay in exfoliated buccal cells would be very beneficial for large-scale biomonitoring studies, as cells can be collected in a minimally invasive manner.

The in vitro MN assay in 2011: origin and fate, biological significance, protocols, high throughput methodologies and toxicological relevance.

Micronuclei (MN) are small, extranuclear bodies that arise in dividing cells from acentric chromosome/chromatid fragments or whole chromosomes/chromatids lagging behind in anaphase and are not included in the daughter nuclei at telophase. The mechanisms of MN formation are well understood; their possible postmitotic fate is less evident. The MN assay allows detection of both aneugens and clastogens, shows simplicity of scoring, is widely applicable in different cell types, is internationally validated, has potential for automation and is predictive for cancer. The cytokinesis-block micronucleus assay (CBMN) allows assessment of nucleoplasmic bridges, nuclear buds, cell division inhibition, necrosis and apoptosis and in combination with FISH using centromeric probes, the mechanistic origin of the MN. Therefore, the CBMN test can be considered as a "cytome" assay covering chromosome instability, mitotic dysfunction, cell proliferation and cell death. The toxicological relevance of the MN test is strong: it covers several endpoints, its sensitivity is high, its predictivity for in vivo genotoxicity requires adequate selection of cell lines, its statistical power is increased by the recently available high throughput methodologies, it might become a possible candidate for replacing in vivo testing, it allows good extrapolation for potential limits of exposure or thresholds and it is traceable in experimental in vitro and in vivo systems. Implementation of in vitro MN assays in the test battery for hazard and risk assessment of potential mutagens/carcinogens is therefore fully justified.

An aphidicolin-block nucleotide excision repair assay measuring DNA incision and repair capacity.

The objective of the present study was to develop a cellular phenotype assay for nucleotide excision repair (NER), using benzo[a]pyrene diol epoxide (BPDE) as model mutagen. Since in vitro exposure to BPDE may lead to DNA strand breaks resulting from both direct interaction with DNA and incisions introduced by the repair enzymes, we aimed to discriminate between both types of breaks using the comet assay and quantified the DNA strand breaks after in vitro challenge of peripheral blood mononucleated cells (PBMCs) with BPDE in the presence or absence of the DNA polymerase inhibitor aphidicolin (APC). The assay was performed with a low (0.5 microM) and a high (2.5 microM) BPDE concentration. The individual NER capacity was defined as the amount of DNA damage induced by BPDE in presence of APC, diminished with the damage induced by BPDE and APC alone. First, the assay was applied to a NER-deficient human fibroblast cell line (XPA-/-) to validate the methodology. Lower repair capacity and a higher amount of BPDE-induced DNA adducts were observed for the XPA-/- fibroblasts as compared to the wild-type fibroblasts. Repeated experiments on PBMCs from four donors showed low intra-individual, intra-experimental and inter-assay variation for both concentrations, indicating the reliability of the method. To assess the inter-individual variation, the assay was applied to PBMCs from 22 donors, comparing the repair capacity after exposure to 0.5 microM (N = 10) and 2.5 microM (N = 12) BPDE. The repair capacity showed a higher inter-individual variation as compared to the intra-individual variation. Moreover, this difference was more pronounced using the low concentration. All these results indicate the adequacy of the method using this low concentration. Further improvement, however, should be recommended by applying the study with low BPDE concentration in a larger population and taking into account the relevant genotypes for NER.

Automated image analysis of cytokinesis-blocked micronuclei: an adapted protocol and a validated scoring procedure for biomonitoring.

Micronuclei (MN) frequencies in peripheral blood lymphocytes have been used worldwide as a biomarker of chromosomal damage for genotoxicity testing and biomonitoring studies. Automation of MN analysis would provide faster and more reliable results with minimizing subjective MN identification. We developed an automated facility for the scoring of the in vitro MN cytokinesis-block assay for biomonitoring on Giemsa-stained slides, fulfilling the following criteria: applicable to the cytokinesis-block micronucleus methodology, discriminating between mono-, bi- and polynucleated cells, MN scoring according to HUMN scoring criteria, false-negative MN rate <10% and false-positive (FP) MN rate <1%. We first adapted the slide preparation protocol to obtain an optimal cell density and dispersion, which is important for image analysis. We developed specific algorithms starting from the cell as a detection unit. The whole detection and scoring process was separated into two distinct steps: in the first step, the cells and nuclei are detected; then, in the second step, the MN are searched for in the detected cells. Since the rate of FP MN obtained by the automatic analysis was in the range of 0.5-1.5%, an interactive visual validation step was introduced, which is not time consuming and allows quality control. Validation of the automated scoring procedure was undertaken by comparing the results of visual and automated scoring of micronucleated mono- and binucleated cells in human lymphocytes induced by two clastogens (ionizing radiation and methyl methane-sulphonate), two aneugens (nocodazole and carbendazim) and one apoptogen (staurosporine). Although the absolute MN frequencies obtained with automated scoring were lower as compared to those detected by visual scoring, a clear dose response for MNBN frequencies was observed with the automated scoring system, indicating that it is able to produce biologically relevant and reliable results. These observations, together with its ability to detect cells, nuclei and MN in accordance with the HUMN scoring criteria, confirm the usability of the automated MN analysis system for biomonitoring.

The Belgian Virtual Tumorbank: A Tool for Translational Cancer Research.

Background: Biobanks play a critical role in cancer research by providing high quality biological samples for research. However, the availability of tumor samples in single research institutions is often limited, especially for rare cancers. In order to facilitate the search for samples scattered among different Belgian institutions, a nationwide virtual tumorbank project was launched and is operational since February 2012. The Belgian Virtual Tumorbank (BVT) network encompasses the tumor biobanks from eleven Belgian university hospitals that collect and store residual human tumor samples locally and is coordinated by the Belgian Cancer Registry. Materials and Methods: A web application was developed and consists of two modules. The registration module (BVTr) centralizes the tumor sample data from the local partner biobanks. The catalog module (BVTc) allows researchers to trace the tumor samples in the 11 tumor biobanks. The BVTc contains patient, medical and technical data, but excludes identifying information to ensure privacy of individuals. Automatic and manual controls guarantee high quality data on the samples requested by scientists for research purposes in oncology. A major advantage of the BVT network is that the available data can be linked to the data of the Belgian Cancer Registry for quality control purposes. Results: Currently, more than 92,000 registrations are available in the catalog. Twenty-seven percent of the residual primary tumor samples originate from breast tissue, but also less frequent localisations such as head and neck (4%), male genital organs (1.7%), and urinary tract (1%) are available. In addition to the residual tumor tissue samples, also other available material can be stored and registered by the local biobanks. The most common type is corresponding normal tissue (19%).Other frequently available materials are plasma, blood, serum, DNA, and buffy coat. Even PBMCs, RNA, cytology, and urine are available in some cases. Discussion and Conclusion: The BVT catalog is a valuable source of information for oncology research and the ultimate goal is to promote multidisciplinary cancer research (i.e., pathogenesis, disease prediction, prevention, diagnosis, treatment, and prognosis) for the benefit of all cancer patients.

Vitamin D insufficient levels during pregnancy and micronuclei frequency in peripheral blood T lymphocytes mothers and newborns (Rhea cohort, Crete).

BACKGROUND & AIMS: Vitamin D deficiency is common among pregnant women and may be associated with several adverse health outcomes including cancer. Micronuclei frequency is a biomarker of early genetic effects and has been used to examine the association between genotoxic exposures and cancer. We examined maternal vitamin D levels during pregnancy in associations with micronuclei frequency in maternal blood and in cord blood. METHODS: 173 mothers and 171 newborns born between 2007 and 2008 in Heraklion (Crete, Greece) were included in the study. Between 14th and 18th weeks of gestation we collected information on maternal diet using food frequency questionnaires (FFQs). We measured maternal serum concentrations of 25-hydroxyvitamin D [25(OH)D] between the first and second trimester of pregnancy. We estimated dietary vitamin D intake using information from FFQ. After delivery we collected cord blood and maternal peripheral blood. We used the cytokinesis-block micronucleus (CBMN) assay to assess the frequencies of micronucleated cells in binucleated T lymphocytes (MNBN). RESULTS: Maternal insufficient serum levels of 25(OH)D (<50 nmol/L) during pregnancy were associated with increased MNBN frequency in cord blood [IRR = 1.32 (95%CI: 1.00, 1.72)]. This increase was higher for newborns with birth weight above the third quartile [≥3.500 kg; IRR = 2.21 (1.26, 3.89)]. Similarly, low levels of dietary vitamin D were associated with increased MNBN frequency in cord blood [middle tertile IRR = 1.08 (0.78, 1.47), lower tertile IRR = 1.51 (1.06, 2.14)]. Insufficient levels of vitamin D were not associated with MNBN in mothers. CONCLUSION: Our results suggest that vitamin D deficiency during pregnancy increases genotoxic risks in newborns. The prevalence of vitamin D deficiency globally is high and it is important to further investigate whether vitamin D supplementation or similar interventions during pregnancy could prevent DNA damage at early stages of life.

Lower nucleotide excision repair capacity in newborns compared to their mothers: a pilot study.

Recognition of the potential vulnerability of children and newborns and protection of their health is essential, especially regarding to genotoxic compounds. Benzo(a)pyrene B(a)P a commonly found carcinogen, and its metabolite BPDE, are known to cross the placenta. To investigate how well newborns are able to cope with BPDE-induced DNA damage, a recent developed nucleotide excision repair cell phenotype assay was applied in a pilot study of 25 newborn daughters and their mothers, using the Alkaline Comet Assay and taking demographic data into account. Newborns seemed to be less able to repair BPDE-induced DNA damage since lower repair capacity levels were calculated compared to their mothers although statistical significance was not reached. Assessment of repair capacity in combination with genotypes will provide important information to support preventive strategies in neonatal care and to define science based exposure limits for pregnant women and children.

Exposure to brominated trihalomethanes in water during pregnancy and micronuclei frequency in maternal and cord blood lymphocytes.

BACKGROUND: Water disinfection by-products have been associated with an increased cancer risk. Micronuclei (MN) frequency in lymphocytes is a marker of genomic damage and can predict adult cancer risk. OBJECTIVE: We evaluated maternal exposure to drinking water brominated trihalomethanes (BTHM) in relation to MN frequency in maternal and cord blood lymphocytes. METHODS: MN frequency was examined in 214 mothers and 223 newborns from the Rhea mother-child cohort in Crete, Greece, in 2007-2008. Residential BTHM water concentrations were estimated during pregnancy using tap water analyses and modeling. Questionnaires on water related habits were used to estimate BTHM exposure from all routes. Associations between BTHM and MN frequency were estimated using negative binomial regression. RESULTS: BTHM concentrations in residential tap water during pregnancy ranged from 0.06 to 7.1 µg/L. MN frequency in maternal binucleated lymphocytes was found to increase with BTHM concentrations in residential water for exposure during the first [rate ratio (RR) for 1 µg/L=1.05; 95% CI: 1.00, 1.11] and second trimesters (RR for 1 µg/L=1.03; 95% CI: 1.00, 1.06), and through all routes of BTHM exposure during the first trimester (RR for 1 µg/week=3.14; 95% CI: 1.16, 8.50). CONCLUSIONS: These findings suggest that exposure to BTHM may increase the frequency of MN in maternal binucleated lymphocytes.

Micronuclei in cord blood lymphocytes and associations with biomarkers of exposure to carcinogens and hormonally active factors, gene polymorphisms, and gene expression: the NewGeneris cohort.

BACKGROUND: Leukemia incidence has increased in recent decades among European children, suggesting that early-life environmental exposures play an important role in disease development. OBJECTIVES: We investigated the hypothesis that childhood susceptibility may increase as a result of in utero exposure to carcinogens and hormonally acting factors. Using cord blood samples from the NewGeneris cohort, we examined associations between a range of biomarkers of carcinogen exposure and hormonally acting factors with micronuclei (MN) frequency as a proxy measure of cancer risk. Associations with gene expression and genotype were also explored. METHODS: DNA and protein adducts, gene expression profiles, circulating hormonally acting factors, and GWAS (genome-wide association study) data were investigated in relation to genomic damage measured by MN frequency in lymphocytes from 623 newborns enrolled between 2006 and 2010 across Europe. RESULTS: Malondialdehyde DNA adducts (M1dG) were associated with increased MN frequency in binucleated lymphocytes (MNBN), and exposure to androgenic, estrogenic, and dioxin-like compounds was associated with MN frequency in mononucleated lymphocytes (MNMONO), although no monotonic exposure-outcome relationship was observed. Lower frequencies of MNBN were associated with a 1-unit increase expression of PDCD11, LATS2, TRIM13, CD28, SMC1A, IL7R, and NIPBL genes. Gene expression was significantly higher in association with the highest versus lowest category of bulky and M1dG-DNA adducts for five and six genes, respectively. Gene expression levels were significantly lower for 11 genes in association with the highest versus lowest category of plasma AR CALUX® (chemically activated luciferase expression for androgens) (8 genes), ERα CALUX® (for estrogens) (2 genes), and DR CALUX® (for dioxins). Several SNPs (single-nucleotide polymorphisms) on chromosome 11 near FOLH1 significantly modified associations between androgen activity and MNBN frequency. Polymorphisms in EPHX1/2 and CYP2E1 were associated with MNBN. CONCLUSION: We measured in utero exposure to selected environmental carcinogens and circulating hormonally acting factors and detected associations with MN frequency in newborns circulating T lymphocytes. The results highlight mechanisms that may contribute to carcinogen-induced leukemia and require further research.

Global gene expression analysis in cord blood reveals gender-specific differences in response to carcinogenic exposure in utero.

BACKGROUND: It has been suggested that fetal carcinogenic exposure might lead to predisposition to develop cancer during childhood or in later life possibly through modulation of the fetal transcriptome. Because gender effects in the incidence of childhood cancers have been described, we hypothesized differences at the transcriptomic level in cord blood between male and female newborns as a consequence of fetal carcinogenic exposure. The objective was to investigate whether transcriptomic responses to dietary genotoxic and nongenotoxic carcinogens show gender-specific mechanisms-of-action relevant for chemical carcinogenesis. METHODS: Global gene expression was applied in umbilical cord blood samples, the CALUX-assay was used for measuring dioxin(-like), androgen(-like), and estrogen(-like) internal exposure, and acrylamide-hemoglobin adduct levels were determined by mass spectrometry adduct-FIRE-procedure(TM). To link gene expression to an established phenotypic biomarker of cancer risk, micronuclei frequencies were investigated. RESULTS: While exposure levels did not differ between sexes at birth, important gender-specific differences were observed in gene expressions associated with these exposures linked with cell cycle, the immune system and more general cellular processes such as posttranslation. Moreover, oppositely correlating leukemia/lymphoma genes between male and female newborns were identified in relation to the different biomarkers of exposure that might be relevant to male-specific predisposition to develop these cancers in childhood. CONCLUSIONS/IMPACT: This study reveals different transcriptomic responses to environmental carcinogens between the sexes. In particular, male-specific TNF-alpha-NF-kB signaling upon dioxin exposure and activation of the Wnt-pathway in boys upon acrylamide exposure might represent possible mechanistic explanations for gender specificity in the incidence of childhood leukemia.

Maternal and gestational factors and micronucleus frequencies in umbilical blood: the NewGeneris Rhea cohort in Crete.

BACKGROUND: The use of cancer-related biomarkers in newborns has been very limited. OBJECTIVE: We investigated the formation of micronuclei (MN) in full-term and preterm newborns and their mothers from the Rhea cohort (Crete), applying for the first time in cord blood a validated semiautomated analysis system, in both mono- and binucleated T lymphocytes. METHODS: We assessed MN frequencies in peripheral blood samples from the mothers and in umbilical cord blood samples. We calculated MN in mononucleated (MNMONO) and binucleated (MNBN) T lymphocytes and the cytokinesis block proliferation index (CBPI) in 251 newborns (224 full term) and 223 mothers, including 182 mother-child pairs. Demographic and lifestyle characteristics were collected. RESULTS: We observed significantly higher MNBN and CBPI levels in mothers than in newborns. In newborns, MNMONO and MNBN were correlated (r = 0.35, p < 0.001), and we found a moderate correlation between MNMONO in mothers and newborns (r = 0.26, p < 0.001). MNMONO frequencies in newborns were positively associated with the mother's body mass index and inversely associated with gestational age and mother's age, but we found no significant predictors of MNBN or CBPI in newborns. CONCLUSIONS: Although confirmation is needed by a larger study population, the results indicate the importance of taking into account both mono- and binucleated T lymphocytes for biomonitoring of newborns, because the first reflects damage expressed during in vivo cell division and accumulated in utero, and the latter includes additional damage expressed as MN during the in vitro culture step.

Evaluation of the genotoxicity of 10 selected dietary/environmental compounds with the in vitro micronucleus cytokinesis-block assay in an interlaboratory comparison.

Complex exposure to xenobiotics is one of the reasons for the reported increase of respiratory diseases, cancer and immunological disturbances. Among such xenobiotics there are food mutagens whose effects on human health in the low level and/or chronic exposure still remains unknown. In the present manuscript, the compounds ethanol (EtOH), 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4'-tetrachlorobiphenyl (PCB 153), benzo[a]pyrene (BaP), 2-amino-3-methylimidazol[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine (PhIP), N-Nitrosodimethylamine (NDMA) and acrylamide (AA) were evaluated in an interlaboratory comparison in the in vitro cytokinesis-block micronucleus assay (CBMN) with objective of assessing the induction of micronuclei, buds and nucleoplasmic bridges in dose responses. Statistically significant increase in MNBN frequency in binucleated cells was recorded by both laboratories for the compound PhIP (2.5µM). The compounds PCB (250 microM) and AA (500 microM) induced statistically significant increase of MNBN although it was recorded by one of the two laboratories. Induction of buds and nucleoplasmic bridges was only observed for BaP (100 microM) and AA (500 microM) by one of the laboratories. Data generated in this study may assist in the interpretation of the mother/newborn biomonitoring study being carried out within project NewGeneris and will contribute to overall knowledge on the genotoxic potential of dietary/environmental toxicants.