Juozas R. Lazutka

Chromosomal aberration frequency in lymphocytes predicts the risk of cancer: results from a pooled cohort study of 22 358 subjects in 11 countries.

Mechanistic evidence linking chromosomal aberration (CA) to early stages of cancer has been recently supported by the results of epidemiological studies that associated CA frequency in peripheral lymphocytes of healthy individuals to future cancer incidence. To overcome the limitations of single studies and to evaluate the strength of this association, a pooled analysis was carried out. The pooled database included 11 national cohorts and a total of 22 358 cancer-free individuals who underwent genetic screening with CA for biomonitoring purposes during 1965–2002 and were followed up for cancer incidence and/or mortality for an average of 10.1 years; 368 cancer deaths and 675 incident cancer cases were observed. Subjects were classified within each laboratory according to tertiles of CA frequency. The relative risk (RR) of cancer was increased for subjects in the medium [RR = 1.31, 95% confidence interval (CI) = 1.07–1.60] and in the high (RR = 1.41; 95% CI = 1.16–1.72) tertiles when compared with the low tertile. This increase was mostly driven by chromosome-type aberrations. The presence of ring chromosomes increased the RR to 2.22 (95% CI = 1.34–3.68). The strongest association was found for stomach cancer [RRmedium = 1.17 (95% CI = 0.37–3.70), RRhigh = 3.13 (95% CI = 1.17–8.39)]. Exposure to carcinogens did not modify the effect of CA levels on overall cancer risk. These results reinforce the evidence of a link between CA frequency and cancer risk and provide novel information on the role of aberration subclass and cancer type.

Genotoxicity of dill (Anethum graveolens L.), peppermint (Mentha×piperita L.) and pine (Pinus sylvestris L.) essential oils in human lymphocytes and Drosophila melanogaster

Genotoxic properties of the essential oils extracted from dill (Anethum graveolens L.) herb and seeds, peppermint (Menthaxpiperita L.) herb and pine (Pinus sylvestris L.) needles were studied using chromosome aberration (CA) and sister chromatid exchange (SCE) tests in human lymphocytes in vitro, and Drosophila melanogaster somatic mutation and recombination test (SMART) in vivo. In the CA test, the most active essential oil was from dill seeds, then followed essential oils from dill herb, peppermint herb and pine needles, respectively. In the SCE test, the most active essential oils were from dill herb and seeds followed by essential oils from pine needles and peppermint herb. Essential oils from dill herb and seeds and pine needles induced CA and SCE in a clear dose-dependent manner, while peppermint essential oil induced SCE in a dose-independent manner. All essential oils were cytotoxic for human lymphocytes. In the SMART test, a dose-dependent increase in mutation frequency was observed for essential oils from pine and dill herb. Peppermint essential oil induced mutations in a dose-independent manner. Essential oil from dill seeds was almost inactive in the SMART test.

Aberrant p16 promoter methylation in smokers and former smokers with nonsmall cell lung cancer.

Hypermethylation of cytosines in CpG‐rich islands of the promoter regions of regulatory genes has been discovered as a common mechanism of gene silencing during carcinogenesis. We analysed 64 primary lung carcinomas for promoter methylation of the tumour suppressor genes (TSGs) p16 (p16INK4a/CDKN2A) and p14 (p14ARF) by methylation‐specific PCR, in order to evaluate aberrant methylation as a potential biomarker for epigenetic alterations in tobacco‐related lung cancer. Methylation of p16 was observed in 34% (22/64) of the lung tumours examined. In particular, p16 methylation occurred in nonsmall cell lung cancer (NSCLC) only, with 41 % (22/54) of the tumours being positive. The highest frequency was found in large cell carcinoma (5/7, 71%), followed by adenocarcinoma (9/25, 36%) and squamous cell carcinoma (7/21, 33%). Methylation of the p14 gene was less frequent in lung cancer (4/52, 8%). When association with tobacco smoking was analysed, 42% (21/50) of NSCLC from ever smokers exhibited p16 methylation. Interestingly, the analysis revealed a significantly higher risk of p16 methylation in former smokers as compared to current smokers [odds ratio (OR) 5.1; 95% confidence interval (CI) 1.3–22]. The difference was retained after adjustment for age (OR 3.7; 95% CI 0.9–17). The promoter methylation results were then combined with data on genetic alterations determined previously in the same set of tumours. This data similarly showed that p16 methylation in parallel with p53 gene mutation or p14 methylation occurred more frequently in former smokers than in current smokers (44% vs. 14%; P = 0.035). Taken together, our data suggest that analysis of promoter methylation in TSGs may provide a valuable biomarker for identification of groups with an elevated risk of cancer, such as smokers and ex‐smokers.

Chromosomal aberrations and sister-chromatid exchanges in Lithuanian populations: effects of occupational and environmental exposures.

Cytogenetic analysis of chromosomal aberrations (CA) in 175,229 cells from 1113 individuals, both unexposed and occupationally or environmentally exposed to heavy metals (mercury and lead), organic (styrene, formaldehyde, phenol and benzo(a)pyrene) and inorganic (sulfur and nitrogen oxides, hydrogen and ammonium fluorides) volatile substances and/or ionizing radiation was performed. In addition, 11,250 cells from 225 individuals were scored for the frequency of sister-chromatid exchanges (SCE). Increased frequencies of CA were found in all occupationally exposed groups. A principal difference between the exposure to heavy metals and organic substances was found: increase in the CA frequency was dependent on duration of exposure to mercury but not dependent on duration of exposure to styrene, formaldehyde and phenol. A higher CA incidence was found in lymphocytes of children living in the vicinity of a plant manufacturing phosphate fertilizers. This indicates that children are a sensitive study group for the assessment of environmental exposure. However, the results of SCE analysis in these children were inconclusive. Exposure to ionizing radiation was found to cause chromosome breaks and chromatid exchanges in Chernobyl clean-up workers and chromatid breaks, chromatid exchanges, dicentric chromosomes and chromosome translocations in workers from the Ignalina Nuclear Power Plant. The increased frequency of chromatid exchanges in individuals exposed to ionizing radiation was quite unexpected. This may be attributed to the action of some unrecognized life-style or occupational factors, or to be a result of radiation-induced genomic instability. Also an increased SCE frequency was found in lymphocytes of Chernobyl clean-up workers.

Sister-chromatid exchanges and their distribution in human lymphocytes in relation to age, sex and smoking

The effects of age, sex and smoking on sister-chromatid exchange (SCE) frequency and distribution in human lymphocytes were assessed by means of multiple linear regression. Differences in SCE scores were associated with all above variables: SCE increased with age and cigarette smoking intensity, and higher SCE frequencies were observed in females. Changes in SCE distribution were associated with age and smoking: the ratio of sample variance to sample mean (heterogeneity index) increased with age and smoking intensity. Cell proliferation kinetics, as measured by replication index, inversely correlated with age. Monte Carlo methods were used to show that in the occupational study, analysis of 20-50 persons per group and 25 cells per person may be recommended.

Immunohistochemistry profiles of breast ductal carcinoma: factor analysis of digital image analysis data

BackgroundMolecular studies of breast cancer revealed biological heterogeneity of the disease and opened new perspectives for personalized therapy. While multiple gene expression-based systems have been developed, current clinical practice is largely based upon conventional clinical and pathologic criteria. This gap may be filled by development of combined multi-IHC indices to characterize biological and clinical behaviour of the tumours. Digital image analysis (DA) with multivariate statistics of the data opens new opportunities in this field.MethodsTissue microarrays of 109 patients with breast ductal carcinoma were stained for a set of 10 IHC markers (ER, PR, HER2, Ki67, AR, BCL2, HIF-1α, SATB1, p53, and p16). Aperio imaging platform with the Genie, Nuclear and Membrane algorithms were used for the DA. Factor analysis of the DA data was performed in the whole group and hormone receptor (HR) positive subgroup of the patients (n = 85).ResultsMajor factor potentially reflecting aggressive disease behaviour (i-Grade) was extracted, characterized by opposite loadings of ER/PR/AR/BCL2 and Ki67/HIF-1α. The i-Grade factor scores revealed bimodal distribution and were strongly associated with higher Nottingham histological grade (G) and more aggressive intrinsic subtypes. In HR-positive tumours, the aggressiveness of the tumour was best defined by positive Ki67 and negative ER loadings. High Ki67/ER factor scores were strongly associated with the higher G and Luminal B types, but also were detected in a set of G1 and Luminal A cases, potentially indicating high risk patients in these categories. Inverse relation between HER2 and PR expression was found in the HR-positive tumours pointing at differential information conveyed by the ER and PR expression. SATB1 along with HIF-1α reflected the second major factor of variation in our patients; in the HR-positive group they were inversely associated with the HR and BCL2 expression and represented the major factor of variation. Finally, we confirmed high expression levels of p16 in Triple-negative tumours.ConclusionFactor analysis of multiple IHC biomarkers measured by automated DA is an efficient exploratory tool clarifying complex interdependencies in the breast ductal carcinoma IHC profiles and informative value of single IHC markers. Integrated IHC indices may provide additional risk stratifications for the currently used grading systems and prove to be useful in clinical outcome studies.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1512077125668949

Chromosome aberrations and rogue cells in lymphocytes of Chernobyl clean-up workers

A cytogenetic analysis was performed on peripheral blood lymphocytes from 183 Chernobyl clean-up workers and 27 control individuals. Increased frequencies of chromosome aberrations were associated with exposure to radiation at Chernobyl, alcohol abuse and a history of recent influenza infection. However, only approximately 20% of Chernobyl clean-up workers had an increased frequency of dicentric and ring chromosomes. At the same time, an increased frequency of acentric fragments in lymphocytes of clean-up workers was characteristic. The use of multivitamins as dietary supplement significantly decreased the frequency of chromosome aberrations, especially of chromatid breaks. Rogue cells were found in lymphocytes of 28 clean-up workers and 3 control individuals. The appearance of rogue cells was associated with a recent history of acute respiratory disease (presumably caused by adenoviral infection) and, probably, alcohol abuse. Dicentric chromosomes in rogue cells were distributed according to a negative binomial distribution. Occurrence of rogue cells due to a perturbation of cell cycle control and abnormal apoptosis is suggested.

Membrane connectivity estimated by digital image analysis of HER2 immunohistochemistry is concordant with visual scoring and fluorescence in situ hybridization results: algorithm evaluation on breast cancer tissue microarrays

IntroductionThe human epidermal growth factor receptor 2 (HER2) is an established biomarker for management of patients with breast cancer. While conventional testing of HER2 protein expression is based on semi-quantitative visual scoring of the immunohistochemistry (IHC) result, efforts to reduce inter-observer variation and to produce continuous estimates of the IHC data are potentiated by digital image analysis technologies.MethodsHER2 IHC was performed on the tissue microarrays (TMAs) of 195 patients with an early ductal carcinoma of the breast. Digital images of the IHC slides were obtained by Aperio ScanScope GL Slide Scanner. Membrane connectivity algorithm (HER2-CONNECT™, Visiopharm) was used for digital image analysis (DA). A pathologist evaluated the images on the screen twice (visual evaluations: VE1 and VE2). HER2 fluorescence in situ hybridization (FISH) was performed on the corresponding sections of the TMAs. The agreement between the IHC HER2 scores, obtained by VE1, VE2, and DA was tested for individual TMA spots and patients maximum TMA spot values (VE1max, VE2max, DAmax). The latter were compared with the FISH data. Correlation of the continuous variable of the membrane connectivity estimate with the FISH data was tested.ResultsThe pathologist intra-observer agreement (VE1 and VE2) on HER2 IHC score was almost perfect: kappa 0.91 (by spot) and 0.88 (by patient). The agreement between visual evaluation and digital image analysis was almost perfect at the spot level (kappa 0.86 and 0.87, with VE1 and VE2 respectively) and at the patient level (kappa 0.80 and 0.86, with VE1max and VE2max, respectively). The DA was more accurate than VE in detection of FISH-positive patients by recruiting 3 or 2 additional FISH-positive patients to the IHC score 2+ category from the IHC 0/1+ category by VE1max or VE2max, respectively. The DA continuous variable of the membrane connectivity correlated with the FISH data (HER2 and CEP17 copy numbers, and HER2/CEP17 ratio).ConclusionHER2 IHC digital image analysis based on membrane connectivity estimate was in almost perfect agreement with the visual evaluation of the pathologist and more accurate in detection of HER2 FISH-positive patients. Most immediate benefit of integrating the DA algorithm into the routine pathology HER2 testing may be obtained by alerting/reassuring pathologists of potentially misinterpreted IHC 0/1+ versus 2+ cases.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1973465132560208.

High titers of antibodies to two human polyomaviruses, JCV and BKV, correlate with increased frequency of chromosomal damage in human lymphocytes

Associations of antibody titers to the JC and BK human polyoma viruses and the frequency of chromosome aberrations (CA) in human peripheral blood lymphocytes were studied. Study group consisted of 33 workers occupationally exposed to low doses of ionizing radiation and 11 control persons. There were no statistically significant differences in the JC and BK virus titer values between two groups of donors. It was found that JC and BK virus titers explained approximately 6% of total inter-individual variation in CA frequency. Such factors as alcohol abuse, age and, in this special group, exposure to ionizing radiation explained an additional 53% of the total variation in CA frequency. In six clean-up workers and one control, rogue cell (cells with multiple chromosome-type aberrations) were found. The incidence of rogue cells correlated significantly with JC and BK virus titers as well as a history of recent acute respiratory disease.

The utility of urine-circulating miRNAs for detection of prostate cancer.

Background:In this paper, the utility of urine-circulating microRNAs (miRNAs) as the potential biomarker of prostate cancer (PCa), the second most prevalent male cancer worldwide, was evaluated.Methods:Cancerous (N=56) and non-cancerous (N=16) prostate tissues were analysed on TaqMan Low Density Array, with the initial screening of 754 miRNAs in a subset of the samples. The abundance of selected miRNAs was analysed in urine specimens from two independent cohorts of patients with PCa (N=215 overall), benign prostatic hyperplasia (BPH; N=23), and asymptomatic controls (ASC; N=62) by means of quantitative reverse transcription PCR.Results:Over 100 miRNAs were found deregulated in PCa as compared with non-cancerous prostate tissue. After thorough validation, four miRNAs were selected for the analysis in urine specimens. The abundance of miR-148a and miR-375 in urine was identified as specific biomarkers of PCa in both cohorts. Combined analysis of urine-circulating miR-148a and miR-375 was highly sensitive and specific for PCa in both cohorts (AUC=0.79 and 0.84) and strongly improved the diagnostic power of the PSA test (AUC=0.85, cohort PCa1), including the grey diagnostic zone (AUC=0.90).Conclusions:Quantitative measurement of urine-circulating miR-148a and miR-375 can serve as the non-invasive tool for sensitive and specific detection of PCa.