E. Piqué

Microsomal epoxide hydrolase and glutathione S-transferase polymorphisms in relation to laryngeal carcinoma risk

Two polymorphic sites of the microsomal epoxide hydrolase gene (EPHX1, 113Tyr-->113His, 139His-->139Arg) and four glutathione S-transferase genes (GSTM1, GSTM3, GSTP1, GSTT1) were genotyped in a group of patients with larynx cancer (N=204) and in a group of healthy controls (N=203), all Spanish caucasians. After adjusting for gender, age, and tobacco smoking, none of the polymorphisms alone were found to be associated with larynx cancer risk. The analysis of EPHX1/GST combinations, however, showed a significant over-representation of patients with a combination of 113Tyr/113Tyr EPHX1 and 105Ile/105Ile GSTP1 (adjusted odds ratio (OR): 1.95; 95% confidence interval (CI): 1.02-3.78). The calculation of the predicted epoxide hydrolase (EH) activity also showed an increased risk for the individuals with both predicted high activity EH and 105Ile/105Ile GSTP1 (OR: 2.90; 95% CI: 1.10-7.67). These results on larynx cancer tend to confirm a former study on lung cancer (Cancer Lett. 173 (2001) 155) suggesting the existence of an interaction between variants of EH and GSTpi, both enzymes being involved in the metabolism of aromatic hydrocarbons, that may increase susceptibility to tobacco-related cancers.

Genetic polymorphism of glutathione S-transferase P1 gene and lung cancer risk.

Objectives: The human GSTTP1 gene is polymorphic with an A → G transition in exon 5 causing a replacement 105 Ile→Val in the GSTP1 protein. The two isoforms, encoded by the alleles GSTP1*A and GSTP1*B, respectively, show different catalytic efficiencies towards some carcinogenic epoxides. In this study we have addressed the possible role of the Ile105Val GSTP1 polymorphism in lung cancer susceptibility.Methods: The polymorphic site was genotyped by RFLP in a group of lung cancer patients (n=164) and in two control groups (healthy smokers, n=132; general population, n=200). All patients and controls were Northwestern Mediterranean Caucasians of the same ethnic origin.Results and Conclusions: The cancer patients showed frequencies of GSTP1*A/A; GSTP1*A/B and GSTP1*B/B (50%, 38%, 11%, respectively) very similar to those of both control groups (healthy smokers: 48%, 41%, 11%). After adjusting for age, sex and smoking status, no association was found between the GSTP1*B allele and lung cancer risk (OR: 1.18; 95% CI: 0.67–2.07). The Ile105val GSTP1 polymorphism was also analysed in combination with the GSTM1 and GSTT1 genes. The results showed that allelism at GSTP1 did not increase the risk associated with the GSTM1 or GSTT1 deletions.

Lung cancer susceptibility in relation to combined polymorphisms of microsomal epoxide hydrolase and glutathione S-transferase P1

Human microsomal epoxide hydrolase (mEH) catalyzes a key step in the biotransformation of benzo[a]pyrene that yields the highly mutagenic (+)-anti-7,8-diol-9,10 epoxide (BPDE). Two polymorphisms have been described in the coding region of the mEH gene (EPHX1) that produce two protein variants: 113Tyr-->113His (exon 3) and 139His-->139Arg (exon 4). We performed a case-control study among Northwestern Mediterranean Caucasians to investigate a possible association between these EPHX1 variants and lung cancer risk. Both EPHX1 polymorphisms were analyzed in a group of lung cancer patients (n=176) and in a control group of healthy smokers (n=187). The results showed a significantly decreased risk for the rare homozygous 113His/113His (adjusted odds ratio (OR): 0.44, 95% confidence interval (CI): 0.27-0.71) and 139Arg/139Arg (adjusted OR: 0.55, 95% CI: 0.33-0.91) compared with the major wild-types 113Tyr/113Tyr and 139His/139His, respectively, as the references. Thereafter, we analyzed the EPHX1 variants in combination with three glutathione S-transferase polymorphic genes (GSTM1, GSTT1, and GSTP1) and we found a significant overepresentation of cancer patients with a combination of exon 3 113Tyr/113Tyr EPHX1 and exon 5 105Ile/105Ile GSTP1 (adjusted OR: 2.34, 95% CI: 1.21-4.52). The polymorphic site within the exon 5 of GSTP1 results in a Ile-->Val substitution, and the isoleucine GSTpi isoform has been found in vitro to be less active than the valine isoform towards the conjugation of BPDE. The 113 Tyr/Tyr EPHX1 encodes for a high-activity mEH. Our results agree with these observations in vitro and suggest that a genetically determined combination of a high-activity mEH and a low-activity GSTpi may increase lung cancer risk among smokers.

Haplotype frequencies of eight Y-chromosome STR loci in Barcelona (North-East Spain)

Abstract Haplotype frequencies for eight Y-chromosomal short tandem repeat (STR) loci were determined in ¶a population sample from Barcelona (NE Spain). After PCR amplification and denaturing PAGE electrophoresis, DYS19, DYS388, DYS389 I/II, DYS390, DYS391, DYS392 and DYS393 loci were typed. Complete eight ¶Y-chromosomal STRs haplotypes could be formed for 223 subjects, among which 137 different haplotypes were observed. The most common haplotype was shared by 13% of the sample, while 108 haplotypes were unique. The discrimination capacity was 61.5% and the gene diversity was 0.978. From the forensic point of view the combined polymorphisms provide a high diagnostic efficiency.

Assessment of developmental delay in the zebrafish embryo teratogenicity assay

In this study we analyzed some aspects of the assessment of developmental delay in the zebrafish embryotoxicity/teratogenicity test and explored the suitability of acetylcholinesterase (AChE) activity as a biochemical marker and as a higher throughput alternative to morphological endpoints such as head-trunk angle, tail length and morphological score. Embryos were exposed from 4 to 52 h post-fertilization (hpf) to a selection of known embryotoxic/teratogen compounds (valproic acid, retinoic acid, caffeine, sodium salicylate, glucose, hydroxyurea, methoxyacetic acid, boric acid and paraoxon-methyl) over a concentration range. They were evaluated for AChE activity, head-trunk angle, tail length and several qualitative parameters integrated in a morphological score. In general, the different patterns of the concentration-response curves allowed distinguishing between chemicals that produced growth retardation (valproic and methoxyacetic acid) and chemicals that produced non-growth-delay related malformations. An acceptable correlation between the morphological score, AChE activity and head-trunk angle as markers of developmental delay was observed, being AChE activity particularly sensitive to detect delay in the absence of malformations.

Catalonian population study of the tetranucleotide repeat loci D3S1358, D8S1179, D18S51 and D19S253

Abstract Allele frequencies for four short tandem repeat loci were determined in a population sample from Catalonia (NE Spain). After denaturing PAGE electrophoresis, 8 alleles were identified for D3S1358 (n = 201), 10 alleles for D8S1179 (n = 198), 13 alleles for D18S51 (n = 197) and 11 alleles for D19S253 (n = 201). No deviation from Hardy-Weinberg equilibrium was found. Complete and relative uniformity in Caucasoid populations has been observed for D18S51 and D8S1179 respectively. Pronounced differences were found between different ethnic groups for both systems. Catalonia and Portugal do not differ for D3S1358 locus. Multiplex PCR amplifications of three loci (D3S1358, D18S51 and D19S253) without overlapping fragment size ranges could be interesting for monochrome automated laser fluorescence devices.

Population study of Aymara Amerindians for the PCR-DNA polymorphisms HUMTH01, HUMVWA31A, D3S1358, D8S1179, D18S51, D19S253, YNZ22 and HLA-DQα

Abstract Allele and genotype frequencies for eight DNA polymorphisms (HUMTH01, HUMVWA31A, D3S1358, D8S1179, D18S51, D19S253, YNZ22 and HLA-DQα) were determined in a population sample of Aymara Indians from Bolivia using PCR. No deviations of the ¶observed allelic frequencies from Hardy-Weinberg equilibrium were found for all the systems studied. Significant differences in the allele frequencies were found between the Aymara and Quechua populations only for HUMVWA31A, which suggests a certain degree of genetic differentiation between the two populations.

Developmental effects and genotoxicity of 10 water disinfection by-products in zebrafish

Disinfection by-products are contaminants produced during drinking water disinfection. Several DBPs have been implicated in a variety of toxic effects, mainly carcinogenic and genotoxic effects. Moreover, DBPs exposure has also been associated with an increased risk of developmental effects. In this study, the developmental toxicity and genotoxicity of 10 DBPs (four trihalomethanes [THMs], five haloacetic acids [HAAs] and sodium bromate) in the zebrafish embryo model were evaluated. Embryos exposed for 72 hours were observed for different endpoints such as growth, hatching success, malformations and lethality. THMs exposure resulted in adverse developmental effects and a significant reduced tail length. Two HAAs, tribromoacetic acid and dichloroacetic acid, along with sodium bromate were found to cause a significant increase in malformation rate. Chloroform, chlorodibromomethane and sodium bromate produced a weak induction of DNA damage to whole embryos. However, developmental effects occurred at a range of concentrations (20-100 μg/mL) several orders of magnitude above the levels that can be attained in fetal blood in humans exposed to chlorinated water. In conclusion, the teratogenic and genotoxic activity observed by some DBPs in zebrafish reinforce the view that there is a weak capacity of disinfection products to cause developmental effects at environmentally relevant concentrations.

The Bubi population of Equatorial Guinea characterised by HUMTH01, HUMVWA31A, HUMCSF1PO, HUMTPOX, D3S1358, D8S1179, D18S51 and D19S253 STR polymorphisms

Abstract Allele frequencies for eight STR loci (HUMTH01, HUMVWA31A, HUMCSF1PO, HUMTPOX, D3S1358, D8S1179, D18S51, D19S253) have been analysed in the Bubi population of Bioko Island, Equatorial Guinea. For all loci, no deviation from Hardy-Weinberg equilibrium was found. Data obtained were compared with that of Caucasian and African populations. Significant differences were found for all systems between all the black populations compared and the Caucasoid population. Similarities were observed between the Bubi and Zimbabweans, and also with African American populations. Also, more affinities were observed between Zimbabweans and Ugandans and Ovambos than between these groups and the Bubi population. From these comparisons it is suggested that in Africa, as in other continents, there is a certain genetic heterogeneity.

Presence of two mutations between father and child in two cases of paternity testing

Abstract We report two cases of paternity testing presenting two inconsistencies between father and child in the same two STR-loci from a total of 16 STR and several VNTR loci examined.