Study underlines that, even in a population of young, asymptomatic and well-chelated patients with TM, there is an impairment of myocardial function and that this condition could be easily detected by more advanced ultrasound techniques such as TDI and SI. The better indices of myocardial function in patients treated with deferiprone clearly needs confirmation from larger prospective studies.

Correlations among biomarkers, an important issue in biomarker research, provide enhanced insight and understanding of the complexity of molecular mechanisms initiated by environmental genotoxic agents in the human organism. Occupational and environmental exposures mostly represent mixtures of genotoxic agents, whereas the specificity of biomarker measurements varies widely. Here, we give an overview of the correlation studies with particular emphasis on DNA adduct biomarker analysis of exposure to polycyclic aromatic hydrocarbons (PAHs) and/or tobacco smoke. We have collected data on correlations between different DNA adduct detection methods, DNA adduct structures and DNA adduct levels in human tissues. Data are also presented on the correlation between DNA adducts and other biomarkers of exposure and of early biological effects, including protein adducts, urinary metabolites and cytogenetic end points. In numerous studies, 32P-postlabelling and immunoassay measurements of DNA adducts recognized the difference between exposure groups similarly; however, at the individual level, there was, in general, not a statistically significant correlation between the two determinations. Inconsistency was found regarding the correlation between the levels of total bulky adducts and specific single DNA adduct structures. A number of studies found a positive correlation between DNA adduct levels in target and surrogate tissues, although stratification for exposure level may have influenced the results. Characteristically, there was a positive correlation between DNA adduct levels in tumour and normal tissue pairs. In general, there was a lack of correlation between DNA adducts and urinary PAH metabolites, but after stratification for particular genetic polymorphisms correlation may have emerged between the two biomarkers of exposure. The correlations with cytogenetic biomarkers were very complex, with examples of both positive correlation and lack of correlation. Exploration of correlations among biomarkers contributes to the further progress of molecular cancer epidemiology and to the selection of the optimal biomarkers for the investigation of human exposure to carcinogens.

Young asymptomatic patients with TM have increased cardiac repolarization variability as assessed by QT variability indices, probably due to cardiac iron deposition. These easily assessed, non-invasive markers could be used to identify increased myocardial repolarization lability early in asymptomatic patients with TM.

Smoking is a major risk factor for lung cancer. This comparative study of smoking-related carcinogen-DNA adducts in pulmonary tissues and peripheral blood lymphocytes aims to further explore the primary DNA damaging processes by cigarette smoke in target and surrogate tissues. Samples of tumour and normal peripheral lung tissue, normal bronchial tissue and peripheral blood lymphocytes were obtained from a total of 85 lung cancer patients who underwent lung resection. Bulky DNA adducts were determined by 32P-postlabelling, and polycyclic aromatic hydrocarbon (PAH)-DNA adducts were detected by (+/-)-7beta, 8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene-DNA chemiluminescence immunoassay (BPDE-DNA CIA) in smaller subsets of tissue samples subject to availability of DNA. Bulky DNA adduct levels ranged between 0.3 and 27.8 adducts/10(8) nucleotides (nt) with mean adduct levels between 2.8 and 11.5 adducts/10(8) nt. Mean PAH-DNA adduct levels were 2.6-6.2 adducts/10(8) nt. Significantly higher bulky DNA adduct levels were detected in smokers' lungs as compared with non-smokers' (P < 0.02). PAH-DNA adduct levels appeared higher in the lungs of smokers compared with non-smokers but the difference was not significant. Lung tumour contained on average a 50% lower DNA adduct level compared with normal lung tissue. A statistically significant positive correlation was found between the DNA adduct levels of the corresponding tumour and normal lung tissue samples in both smokers and non-smokers using both methodologies. Bulky DNA adduct levels in normal lung and blood lymphocytes correlated significantly in non-smokers only (r = 0.55, P = 0.023). In lung tumour DNA samples there was a weak correlation between values obtained by 32P-postlabelling and by the BPDE-DNA immunoassay (r = 0.27, P = 0.054). However, with normal lung DNA samples, values obtained by the two assays did not correlate.

Tobacco smoke contains many alkylating agents that can react with DNA to produce O(4)-ethylthymidine (O(4)-etT) and several other types of promutagenic base modifications. Our aims were (i) to confirm results of a pilot study (Godschalk, R., Nair, J., Schooten, F. J., Risch, A., Drings, P., Kayser, K., Dienemann, H. and Bartsch, H. (2002) Comparison of multiple DNA adduct types in tumor adjacent human lung tissue: effect of cigarette smoking. Carcinogenesis, 23, 2081-2086) on the formation of O(4)-etT in smokers' lung; (ii) to explore associations between levels of O(4)-etT and smoking status and (iii) to investigate whether a correlation exists between levels of O(4)-etT and bulky (polycyclic aromatic hydrocarbons-derived) DNA adducts. Archived DNA samples originated from histologically normal peripheral lung tissues of 64 Hungarian lung cancer patients, who underwent lung resection. O(4)-etT was determined by an immunoenriched (32)P-postlabelling-high-performance liquid chromatography method. Levels of bulky DNA adducts were determined by the nuclease P1 adduct-enriched (32)P-postlabelling. O(4)-etT levels ranged from 0.01 to 3.91 adducts/10(8) thymidines. In the combined group of subjects who smoked until surgery or gave up smoking at most 1 year before it, the mean level of O(4)-etT was 1.7-fold (P = 0.015) and of bulky DNA adducts 2.2-fold (P < 0.0001) higher than in long-term ex-smokers (LES) and never-smokers (NS) combined. We found no significant correlation between the individual levels of the two DNA adduct types. No dose-response was detected between O(4)-etT formation and smoking dose. In one-third of LES, O(4)-etT levels were above the 2.0-fold mean level of adducts found in NS, indicating its high persistence. Our results confirm the smoking-related formation of O(4)-etT in human lung DNA that should be explored as biomarker. Its long persistence in target tissue implicates a role of this potentially miscoding lesion in tobacco smoking-associated cancers.

In this study, we compared the long-term effects of different iron chelation regimens (deferoxamine, deferiprone, deferoxamine + deferiprone, and deferasirox) in preventing or reversing endocrinopathy (diabetes mellitus, hypothyroidism, or hypogonadism) and bone disease (measured through DEXA) in 165 adults with β-thalassemia major (TM) (mean age 39.9 ± 8.3 years, 43 % males). After five consecutive years of therapy, patients on deferasirox had the highest decrease in the prevalence of any endocrinopathy compared to other chelators which either had no change (deferiprone and deferoxamine) or had an increase (deferoxamine + deferiprone), p = 0.015. This was attributed to a lower proportion of patients on deferasirox developing new-onset endocrinopathy and higher proportion showing reversal of disease, compared to other chelators. A serum ferritin level of >1300 ng/mL predicted the development of new endocrinopathy (p = 0.025) while a level of <200 ng/mL predicted reversal of existing endocrinopathy (p = 0.147). A significant increase in mean BMD T-score (p < 0.001) and a considerable decrease in osteoporosis prevalence were observed in patients receiving deferasirox but not other chelators. Iron chelation therapy with deferasirox has a role in the prevention of endocrinopathy and reversal of existing disease.

Background: Tobacco-smoke, airborne, and dietary exposures to polycyclic aromatic hydrocarbons (PAHs) have been associated with reduced prenatal growth. Evidence from biomarker-based studies of low-exposed populations is limited. Bulky DNA adducts in cord blood reflect the prenatal effective dose to several genotoxic agents including PAHs.Objectives: We estimated the association between bulky DNA adduct levels and birth weight in a multicenter study and examined modification of this association by maternal intake of fruits and vegetables during pregnancy.Methods: Pregnant women from Denmark, England, Greece, Norway, and Spain were recruited in 2006–2010. Adduct levels were measured by the 32P-postlabeling technique in white blood cells from 229 mothers and 612 newborns. Maternal diet was examined through questionnaires.Results: Adduct levels in maternal and cord blood samples were similar and positively correlated (median, 12.1 vs. 11.4 adducts in 108 nucleotides; Spearman rank correlation coefficient = 0.66, p < 0.001). Cord blood adduct levels were negatively associated with birth weight, with an estimated difference in mean birth weight of –129 g (95% CI: –233, –25 g) for infants in the highest versus lowest tertile of adducts. The negative association with birth weight was limited to births in Norway, Denmark, and England, the countries with the lowest adduct levels, and was more pronounced in births to mothers with low intake of fruits and vegetables (–248 g; 95% CI: –405, –92 g) compared with those with high intake (–58 g; 95% CI: –206, 90 g)Conclusions: Maternal exposure to genotoxic agents that induce the formation of bulky DNA adducts may affect intrauterine growth. Maternal fruit and vegetable consumption may be protective.Citation: Pedersen M, Schoket B, Godschalk RW, Wright J, von Stedingk H, Törnqvist M, Sunyer J, Nielsen JK, Merlo DF, Mendez MA, Meltzer HM, Lukács V, Landström A, Kyrtopoulos SA, Kovács K, Knudsen LE, Haugen M, Hardie LJ, Gützkow KB, Fleming S, Fthenou E, Farmer PB, Espinosa A, Chatzi L, Brunborg G, Brady NJ, Botsivali M, Arab K, Anna L, Alexander J, Agramunt S, Kleinjans JC, Segerbäck D, Kogevinas M. 2013. Bulky DNA adducts in cord blood, maternal fruit-and-vegetable consumption, and birth weight in a European mother–child study (NewGeneris). Environ Health Perspect 121:1200–1206; http://dx.doi.org/10.1289/ehp.1206333

There is a need for validation of biomarkers. Our aim is to review published work on the validation of selected biomarkers: bulky DNA adducts, N-nitroso compounds, 1-hydroxypyrene, and oxidative damage to DNA. A systematic literature search in PubMed was performed. Information on the variability and reliability of the laboratory tests used for biomarkers measurements was collected. For the evaluation of the evidence on validation we referred to the ACCE criteria. Little is known about intraindividual variation of DNA adduct measurements, but measurements have a good repeatability irrespective of the technique used for their identification; reproducibility improved after the correction for a laboratory factor. A high-sensitivity method is available for the measurement of 1-hydroxypyrene in urine. There is consensus on validation of biomarkers of oxidative damage DNA based on the comet assay and chromatographic measurement in blood while urinary measurements by chromatographic assays are well validated, and ELISA-based assays appear to lack specificity. Immunoassays for the quantification of adducts of N-nitroso compounds are useful for large epidemiological studies, given their sensitivity, the small amount of DNA required and their potential for rapid and high-throughput analysis.