The frequency of micronuclei (MN) in peripheral blood lymphocytes (PBL) is extensively used as a biomarker of chromosomal damage and genome stability in human populations. Much theoretical evidence has been accumulated supporting the causal role of MN induction in cancer development, although prospective cohort studies are needed to validate MN as a cancer risk biomarker. A total of 6718 subjects from of 10 countries, screened in 20 laboratories for MN frequency between 1980 and 2002 in ad hoc studies or routine cytogenetic surveillance, were selected from the database of the HUman MicroNucleus (HUMN) international collaborative project and followed up for cancer incidence or mortality. To standardize for the inter-laboratory variability subjects were classified according to the percentiles of MN distribution within each laboratory as low, medium or high frequency. A significant increase of all cancers incidence was found for subjects in the groups with medium (RR=1.84; 95% CI: 1.28-2.66) and high MN frequency (RR=1.53; 1.04-2.25). The same groups also showed a decreased cancer-free survival, i.e. P=0.001 and P=0.025, respectively. This association was present in all national cohorts and for all major cancer sites, especially urogenital (RR=2.80; 1.17-6.73) and gastro-intestinal cancers (RR=1.74; 1.01-4.71). The results from the present study provide preliminary evidence that MN frequency in PBL is a predictive biomarker of cancer risk within a population of healthy subjects. The current wide-spread use of the MN assay provides a valuable opportunity to apply this assay in the planning and validation of cancer surveillance and prevention programs.

The pharmacokinetics and pharmacodynamics of morphine are under the control of several polymorphic genes, which can account for part of the observed interindividual variation in pain relief. We focused on two such genes: ABCB1/MDR1, a major determinant of morphine bioavailability, and OPRM1, which encodes for the mu-opioid receptor, the primary site of action for morphine. One hundred and forty-five patients of Italian origin undergoing morphine therapy were genotyped for the single-nucleotide polymorphism (SNP) C3435T of ABCB1/MDR1 and for the A80G SNP of OPRM1. Pain relief variability was significantly (P<0.0001) associated with both polymorphisms. Combining the extreme genotypes of both genes, the association between patient polymorphism and pain relief improved (P<0.00001), allowing the detection of three groups: strong responders, responders, and non-responders, with sensitivity close to 100% and specificity more than 70%. This study provides a good example of the possible clinical use of pharmacogenetics.

Cigarette smoke is a mixture of chemicals having direct and/or indirect toxic effects on different lung cells. We investigated the effect of cigarette smoke on human lung fibroblasts (HFL-1) oxidation and apoptosis. Cells were exposed to various concentrations (1, 5, and 10%) of cigarette smoke extract (CSE) for 3 h, and oxidative stress and apoptosis were assessed by fluorescence-activated cell sorting and confocal laser fluorescence microscopy. Both oxidative stress and apoptosis exhibited a dose-response relationship with CSE concentrations. Lung fibroblasts also showed marked DNA fragmentation at the Comet assay after exposure to 10% CSE. Coincubation of HLF-1 cells with N-acetylcysteine (1 mM) during CSE exposure significantly reduced oxidative stress, apoptosis, and DNA fragmentation, whereas preincubation (3 h) with the glutathione-depleting agent buthionine sulfoximine (125 μM) produced a significant increase of oxidative stress. Cigarette smoke is a potent source of oxidative stress, DNA damage, and apoptosis for HFL-1 cells, and we speculate that this could contribute to the development of pulmonary emphysema in the lungs of smokers.

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The RET protooncogene is constitutively activated by point mutations in hereditary medullary thyroid carcinomas (MTCs). RET somatic point mutations have also been reported in 40-50% of sporadic MTCs. Several single nucleotide polymorphisms of the RET gene have been described in the general population as well as in patients with MTC. These allelic variants do not seem to confer any transforming activity to the tyrosine kinase domain of the RET gene. Because the exon 11 RET polymorphism determines an important aminoacidic variation (G691S), we studied its frequency in 212 subjects, 106 sporadic MTC patients and 106 normal age-, sex-, race-, and geographic origin-matched controls. In 46 cases of sporadic MTCs, we also studied the cosegregation of somatic RET gene mutation and G691S polymorphism as well as the linkage of the polymorphism with RET germline mutation in 60 members of eight multiple endocrine neoplasia type 2 families. The influence of this polymorphism on the RET gene transcription has also been studied. In parallel we analyzed the frequencies of another three neutral polymorphisms (L769L, S836S, S904S). We found a statistically significant (P = 0.029) higher allelic frequency of G691S polymorphism in MTCs (27.83%) than that found in normal controls (18.86%), at variance with the three neutral polymorphisms whose frequencies were not different in patients and controls. With this study we excluded the influence of the G691S polymorphism on RET mRNA expression, the development of the somatic RET mutation, the linkage with the germline RET mutation, the younger onset of the MTCs, and the clinical outcome of the disease. A putative role of the G691S polymorphism as genetic modifier in the normal subjects remains to be established.

No abstract

Molecular sensing in the lingual mucosa and in the gastro-intestinal tract play a role in the detection of ingested harmful drugs and toxins. Therefore, genetic polymorphisms affecting the capability of initiating these responses may be critical for the subsequent efficiency of avoiding and/or eliminating possible threats to the organism. By using a tagging approach in the region of Taste Receptor 2R38 (TAS2R38) gene, we investigated all the common genetic variation of this gene region in relation to colorectal cancer risk with a case-control study in a German population (709 controls and 602 cases) and in a Czech population (623 controls and 601 cases). We found that there were no significant associations between individual SNPs of the TAS2R38 gene and colorectal cancer in the Czech or in the German population, nor in the joint analysis. However, when we analyzed the diplotypes and the phenotypes we found that the non-taster group had an increased risk of colorectal cancer in comparison to the taster group. This association was borderline significant in the Czech population, (OR = 1.28, 95% CI 0.99–1.67; Pvalue = 0.058) and statistically significant in the German population (OR = 1.36, 95% CI 1.06–1.75; Pvalue = 0.016) and in the joint analysis (OR = 1.34, 95% CI 1.12–1.61; Pvalue = 0.001). In conclusion, we found a suggestive association between the human bitter tasting phenotype and the risk of CRC in two different populations of Caucasian origin.

Recent evidence indicates that small, nonprotein-coding RNA molecules, called microRNAs (miRNAs), control cell growth, differentiation, and apoptosis, and are also involved in tumorigenesis. miRNAs can bind to the 3' untranslated regions (3'UTRs) of messenger RNAs and interfere with their translation. We hypothesized that common polymorphisms within their genes or within their targets could have an important impact for an individual's risk to develop complex diseases. In this study, we selected the 3'UTRs of 129 genes involved in pathways commonly acknowledged as important for cancer, and we identified putative miRNA-binding sites by means of specialized algorithms (PicTar, DIANA-MicroT, miRBase, miRanda, TargetScan, and MicroInspector). Then we investigated 79 single-nucleotide polymorphisms (SNPs) within the putative binding sites for their ability to affect or impair the binding with the miRNA by assessing the DeltaDeltaG, the variation of DeltaG (Gibbs free energy), through comparing the wild-type and their corresponding variant alleles. Moreover, we reported seven identified SNPs in seven pre-miRNA hairpin regions and one SNP in the mature sequence of miR-608. Considering the validation status of the SNPs and their frequencies, we found at least 23 candidate polymorphisms of biological relevance that we propose for further investigation in case-control association studies.