Cyclin D1 (CCND1) G870A gene polymorphism is an ethnicity-dependent risk factor for digestive tract cancers: a meta-analysis comprising 20,271 subjects

Published data on the association between Cyclin D1 (CCND1) G870A gene polymorphism and digestive tract cancers (DTC) are inconclusive. We carried out a meta-analysis of published case-control studies to derive a more precise estimation of the association. Relevant studies were identified from PubMed, EMBASE, and China National Knowledge Infrastructure up to February 1st, 2011. Crude odds ratios (OR) and 95% confidence intervals (CI) were used to investigate the strength of the association. Data were available from a total of 33 case-control studies with 8534 cases and 11,737 controls. The combined results based on all studies showed that there was a statistically significant link between CCND1 G870A polymorphism and DTC risk (GG vs. AA: OR=0.83, 95%CI=0.71-0.96). In the analysis of ethnic groups, we found the A allele carriers had a significantly increased DTC susceptibility among Caucasians, but not among Asians. When stratified for tumor location, the results based on all studies only showed the variant allele 870A might have a significantly increased risk of colorectal cancer (CRC), especially of rectal cancer (GG vs. AA: OR=0.71, 95%CI=0.58-0.89). When stratifying by the stage and histological differentiation of CRC, we only observed that patients had a significantly higher frequency of CCND1 870 AA than non-cancer patients among Caucasians. The A allele carriers (hetero- or homozygotes) were significantly more common in cases with a family history of CRC than in controls. There was no evidence of publication bias for CCND1 G870A polymorphism with DTC risk. In summary, this meta-analysis demonstrates that the CCND1 G870A polymorphism may be an ethnicity-dependent risk factor for DTC. And this genetic variant may increase the risk of rectal cancer, but not colon cancer.     

Spectroscopic studies of DNA and ATP binding to human polynucleotide kinase: evidence for a ternary complex

Human polynucleotide kinase (hPNK), which possesses both 5'-DNA kinase and 3'-DNA phosphatase activities, is a DNA repair enzyme required for processing and rejoining of single- and double-strand-break termini. Full-length hPNK was subjected to sedimentation and spectroscopic analyses in association with its ligands, a 20-mer oligonucleotide, ATP, and AMP-PNP (a nonhydrolyzable analogue of ATP). Sedimentation equilibrium measurements indicated that hPNK was a monomer in the presence and absence of the ligands. Circular dichroism measurements revealed that the ligands induced different conformational changes in hPNK, although AMP-PNP induced the same conformational changes as ATP. CD also indicated that the oligonucleotide could bind to the protein-AMP-PNP complex. Protein-ligand binding affinities and stoichiometries were determined by measuring changes in protein intrinsic fluorescence. Titrating hPNK with the oligonucleotide indicated tight binding with a K(d) value of 1.3 microM and with 1:1 stoichiometry. A 5'-phosphorylated oligonucleotide with the same sequence exhibited an almost 6-fold lower affinity (K(d) value, 7.2 microM). ATP and AMP-PNP bound with high affinity (K(d) values, respectively, of 1.4 and 1.6 microM), and the observed binding stoichiometries were 1:1. Furthermore, the nonphosphorylated oligonucleotide was able to bind to hPNK in the presence of AMP-PNP with a K(d) value of 2.5 microM, confirming the formation of a ternary complex. This study provides the first direct physical evidence for such a ternary complex involving a polynucleotide kinase, AMP-PNP, and an oligonucleotide, and supports a reaction mechanism in which ATP and DNA bind simultaneously to the enzyme.     

Both G-type domains of protein S are required for the high-affinity interaction with C4b-binding protein.

Anticoagulant protein S interacts with the complement regulatory protein C4b-binding protein (C4BP) via its sex-hormone-binding globulin (SHB6)-like region, which contains two globular (G) domains. Similar G domains are found in Gas6, a protein homologous to protein S, which is not known to bind C4BP or to have any anticoagulant activity. To determine the relative importance of the two G domains in protein S for C4BP protein binding, three recombinant protein S chimeras were produced having either of the two globular domains, or the whole SHB6-like globulin region, replaced by corresponding parts from Gas6. The chimeras were tested for binding to immobilized C4BP using surface-plasmon-resonance technology and microtiter plate-based assays. In both systems, chimeras containing either only globular domains G1 or G2 from protein S were found to bind C4BP. Binding was stimulated by Ca2+ in a manner similar to that found for wild-type protein S. The affinities for C4BP of both chimeras containing individual G domains from protein S, were lower than that of wild-type protein S. Chimera II, containing the G1 domain from protein S, consistently bound C4BP more efficiently than chimera I, which had the protein S-derived G2 domain. The chimera containing the whole SHB6-like globulin region from Gas6 interacted considerably more weakly with C4BP. Our results demonstrate that both G domains of protein S are involved in the interaction between protein S and C4BP and that full affinity binding is dependent on contributions from both domains.     

Biological membrane modeling with a liquid/liquid interface. Probing mobility and environment with total internal reflection excited fluorescence.

Total internal reflection of exciting light, in combination with fluorescence intensity and polarization measurements, was used to selectively study fluorescent compounds adsorbed to the interface region between two immiscible liquids. A fluorometer was constructed which provided excitation at variable angles of incidence and allowed sensitive detection of polarized fluorescence emitted from the interface. The compound 4,4'-bis-1-phenylamino-8-naphthalenesulfonate (bis-ANS) was examined at a decalin/water interface and was found to possess remarkable affinity for the interface region with the bulk of the adsorbed molecule residing in the decalin phase. The adsorbed fluorophore displayed an apparent hindered rotation in the plane of the interface with a rotational diffusion coefficient 3- to 12-fold lower than that expected for bis-ANS in solution. While other dyes examined were not found to be significantly surface active, the addition of cationic surfactant sufficed to induce adsorption of the anionic fluorophore 1-aminonaphthalene-3,6,8-trisulfonic acid. This fluoropore was found to reside in an aqueous environment when bound to the interface, and it also exhibited hindered rotation in the plane of the interface. As the concentrations of the dyes were increased, both adsorbed dyes exhibited polarization reductions consistent with excitation energy transfer. Adsorption of bis-ANS was reversed by addition of bovine serum albumin. The membrane protein cytochrome b5 was found not to bind at the decalin/water interface, indicating that interaction with lipid is required for its adherence to biological membranes.     

Phenolic Azo Dye Oxidation by Laccase from Pyricularia oryzae

Laccase oxidation of phenolic azo dyes was examined with a commercially available laccase from Pyricularia oryzae as the model. Methyl-, methoxy-, chloro-, and nitro-substituted derivatives of 4-(4(prm1)-sulfophenylazo)-phenol were examined as substrates for this laccase. Only the substituents on the phenolic ring were changed. Among the dyes examined, only 2-methyl-, 2-methoxy-, 2,3-dimethyl-, 2,6-dimethyl-, 2,3-dimethoxy-, and 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol served as substrates. Preliminary kinetic studies suggest that 2,6-dimethoxy-substituted 4-(4(prm1)-sulfophenylazo)-phenol is the best substrate. Laccase oxidized the 2,6-dimethyl derivative of 4-(4(prm1)-sulfophenylazo)-phenol to 4-sulfophenylhydroperoxide (SPH) and 2,6-dimethyl-1,4-benzoquinone. The 2-methyl- and 2-methoxy-substituted dyes were oxidized to SPH and either 2-methyl- or 2-methoxy-benzoquinone. Six products were formed from laccase oxidation of the 2,6-dimethoxy-substituted dye. Three of them were identified as SPH, 4-hydroxybenzenesulfonic acid, and 2,6-dimethoxybenzoquinone. A mechanism for the formation of benzoquinone and SPH from laccase oxidation of phenolic azo dyes is proposed. This study suggests that laccase oxidation can result in the detoxification of azo dyes.     

Characterization of mammalian eIF4E-family members.

The translational factor eukaryotic initiation factor 4E (eIF4E) is a central component in the initiation and regulation of translation in eukaryotic cells. Through its interaction with the 5' cap structure of mRNA, eIF4E functions to recruit mRNAs to the ribosome. The accumulation of expressed sequence tag sequences has allowed the identification of three different eIF4E-family members in mammals termed eIF4E-1, eIF4E-2 (4EHP, 4E-LP) and eIF4E-3, which differ in their structural signatures, functional characteristics and expression patterns. Unlike eIF4E-1, which is found in all eukaryotes, orthologues for eIF4E-2 appear to be restricted to metazoans, while those for eIF4E-3 have been found only in chordates. Like prototypical eIF4E-1, eIF4E-2 was found to be ubiquitously expressed, with the highest levels in the testis. Expression of eIF4E-3 was detected only in heart, skeletal muscle, lung and spleen. Similarly to eIF4E-1, both eIF4E-2 and eIF4E-3 can bind to the mRNA cap-structure. However, in contrast to eIF4E-1 which interacts with both the scaffold protein, eIF4G and the translational repressor proteins, the eIF4E-binding proteins (4E-BPs), eIF4E-2 and eIF4E-3 each possesses a range of partial activities. eIF4E-2 does not interact with eIF4G, but does interact with 4E-BPs. Conversely, eIF4E-3 interacts with eIF4G, but not with 4E-BPs. Neither eIF4E-2 nor eIF4E-3 is able to rescue the lethality of eIF4E gene deletion in yeast. It is hypothesized that each eIF4E-family member fills a specialized niche in the recruitment of mRNAs by the ribosome through differences in their abilities to bind cap and/or to interact with eIF4G and the 4E-BPs.     

Pnk1, a DNA kinase/phosphatase required for normal response to DNA damage by gamma-radiation or camptothecin in Schizosaccharomyces pombe.

We report the characterization of Pnk1, a 45-kDa homolog of the human polynucleotide kinase PNKP in Schizosaccharomyces pombe. Recombinant Pnk1 like human PNKP exhibits both 5'-DNA kinase and 3'-DNA phosphatase activities in vitro. Furthermore, we detected 3'-DNA phosphatase activity with a single-stranded substrate in extracts from wild-type yeast, but no activity was detected in pnk1delta strains. We have shown that GFP-tagged Pnk1 like mammalian PNKP localizes to the nucleus. Deletion of pnk1 does not affect cell growth under normal conditions but results in significant hypersensitivity to gamma-radiation or camptothecin, an inhibitor of topoisomerase I, suggesting that Pnk1 plays an important role in the repair of DNA strand breaks produced by these agents. The pnk1 deletion mutants were not hypersensitive to ethyl methanesulfonate, methyl methanesulfonate, or 4-nitroquinoline N-oxide. Expression of human PNKP in pnk1delta cells restores resistance to gamma-radiation or camptothecin, suggesting that the functions of yeast Pnk1 and human PNKP have been conserved.     

Spectrofluorometry of dyes with DNAs of different base composition and conformation

The increase in fluorescence, upon interaction with several fluorescent dyes was found to depend on the base composition of DNA. 4',6-Diamidino-2-phenylindole-2 HCl and Hoechst 33258 which bind to AT base pairs show a logarithmic relation. This relation is linear when DNAs interact with mithramycin, chromomycin A3, and olivomycin, which bind to GC base pairs. Deviations from these relationships were observed for T2 DNA, containing hydroxymethylcytosine, and for 2C DNA, containing hydroxymethyluracil. On the basis of these data, a simple technique is proposed for determination of base composition. The presence of abnormal bases can be monitored by the use of given fluorophores. Fluorescence intensities were not modified upon linearization of covalently closed circular plasmid pBR322. Denaturation of lambda DNA was accompanied by a decrease of fluorescence, when complexed with the five dyes tested.     

Synthetic dye decolorization capacity of white rot fungus Dichomitus squalens

The ability to decolorize eight chemically different synthetic dyes (Orange G, Amaranth, Orange I, Remazol Brilliant Blue R (RBBR), Cu-phthalocyanin, Poly R-478, Malachite Green and Crystal Violet) by the white rot fungus Dichomitus squalens was evaluated on agar plates. The fungus showed high decolorization capacity and was able to decolorize all dyes tested, but not to the same extent. Some of the dyes did not limit the decolorization capacity of the strain tested even at a concentration of 2g/l. The presence of the dyes in solid media reduced the mycelial growth rate of D. squalens; a positive correlation was found between the growth rate and the decolorization ability. Decolorization of Orange G and RBBR was studied also in liquid culture, where both dyes caused an enhancement of ligninolytic enzyme and overall hydrogen peroxide production and a decrease of biomass production. RBBR was removed to a higher extent than Orange G.     

DNA sequence recognition in the minor groove by hairpin microgonotropens

Two novel microgonotropens (MGTs) comprised of hairpin N-propylaminepyrrole polyamides linked to a Hoechst 33258 (Ht) analogue (3 and 4) were synthesized on solid phase by adopting an Fmoc technique using a series of HOBt mediated coupling reactions. The dsDNA-binding properties of MGTs 3 and 4 were determined by thermal denaturation experiments. Both MGTs were found to be selective for their nine-bp match dsDNA sequence 9 and were less tolerant of G/C bp substitutions in the binding region than linear progenitor MGT 1. MGT 3 was intolerant of a G/C substitution located in the middle of the binding region and did not bind to sequences 13 and 14. MGT 4 also did not bind to sequence 13, and its linker-bound Ht moiety was found to be more sensitive to a G/C substitution in the Ht-binding target, as demonstrated by the lack of binding to sequence 16.     

Supramolecularity creates nonstandard protein ligands

Congo red and a group of structurally related dyes long used to stain amyloid proteins are known to associate in water solutions. The self-association of some dyes belonging to this group appears particularly strong. In water solutions their molecules are arranged in ribbon-like micellar forms with liquid crystalline properties. These compounds have recently been found to form complexes with some native proteins in a non-standard way. Gaps formed by the local distribution of beta-sheets in proteins probably represent the receptor sites for these dye ligands. They may result from higher structural instability in unfolding conditions, but also may appear as long range cooperative fluctuations generated by ligand binding. Immunoglobulins G were chosen as model binding proteins to check the mechanism of binding of these dyes. The sites of structural changes generated by antigen binding in antibodies, believed to act as a signal propagated to distant parts of the molecule, were assumed to be suitable sites for the complexation of liquid-crystalline dyes. This assumption was confirmed by proving that antibodies engaged in immune complexation really do bind these dyes; as expected, this binding affects their function by significantly enhancing antigen binding and simultaneously inhibiting C1q attachment. Binding of these supramolecular dyes by some other native proteins including serpins and their natural complexes was also shown. The strict dependence of the ligation properties on strong self-assembling and the particular arrangement of dye molecules indicate that supramolecularity is the feature that creates non-standard protein ligands, with potential uses in medicine and experimental science.     

Redox-mediated decolorization of recalcitrant textile dyes by <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> WL1 laccase

The efficiency of crude and partially purified Trichoderma harzianum WL1 laccase for the decolorization of synthetic dyes (Rhodamine 6G, Erioglaucine and Trypan blue) with complex aromatic structures were evaluated. Selection of dyes was based on their extensive usage in local dyeing and textile industries around the study area. Studies on the role of redox potential of laccases on dye decolorization are rarely discussed and hence, for the first time we have shown the redox mediated dye decolorizing efficiency of T. harzianum WL1 laccase with the commonly employed redox mediator 1-hydroxybenzotriazole (HBT). The process parameters such as initial dye concentration, enzyme load and HBT concentration were studied and found that they had a great influence on dye removal process. When the dyes were treated with increased concentration of enzyme, it showed a greater percentage of decolorization. Compared to the crude laccase, partially purified laccase accounts for maximum decolorization of all the dyes studied. In addition, the rate of dye decolorization was considerably enhanced in presence of 4 mM HBT. Maximum and minimum decolorization were recorded for Rhodamine 6G and Trypan blue, respectively. The results of this study further confirmed that, T. harzianum laccase was found to be suitable with HBT and this laccase-mediator system (LMS) could be applied for the decolorization of various classes of dyes.     

DNA ligation catalyzed by human topoisomerase II alpha

The DNA ligation reaction of topoisomerase II is essential for genomic integrity. However, it has been impossible to examine many fundamental aspects of this reaction because ligation assays historically required the enzyme to cleave a DNA substrate before sealing the nucleic acid break. Recently, a cleavage-independent DNA ligation assay was developed for human topoisomerase IIalpha [Bromberg, K. D., Hendricks, C., Burgin, A. B., and Osheroff, N. (2002) J. Biol. Chem. 277, 31201-31206]. This assay overcomes the requirement for DNA cleavage by monitoring the ability of the enzyme to ligate a nicked oligonucleotide in which the 5'-terminal phosphate at the nick has been activated by covalent attachment to the tyrosine mimic, p-nitrophenol. The cleavage-independent ligation assay was used to more fully characterize the DNA ligation activity of human topoisomerase IIalpha. Results suggest that the active site tyrosine contributes little to the catalysis of DNA ligation beyond its primary role as an activating/leaving group. Although arginine 804 (the residue immediately N-terminal to the active site tyrosine) has been proposed to help anchor the 5'-DNA terminus during cleavage, conversion of this residue to alanine had only a modest effect on DNA ligation. Thus, it appears that arginine 804 does not play an essential role in DNA strand joining. In contrast, disruption of base pairing at the 5'-DNA terminus abrogated DNA ligation in the absence of a covalent enzyme-DNA bond. Therefore, it is proposed that base pairing represents a secondary mechanism for aligning the 5'-DNA termini for ligation. Finally, the human enzyme appears to ligate the two scissile bonds of a cleavage site in a nonconcerted fashion.     

Stock dynamics of Cleisthenes herzensteini in the central and southern Yellow Sea

Anthropogenic activities and environmental changes have had a significant effect on the fishery ecosystem, biological characteristics, and population dynamics of marine fishes. Overfishing threatens the sustainability of many populations. We evaluated changes in the biological characteristics, distribution, and abundance of Cleisthenes herzensteini using bottom trawl survey data collected from 1985 to 2010 in the central and southern Yellow Sea. The dominant body length of C. herzensteini during spring was 80–160 mm in 1986, 60–160 mm in 1998, and 41–80 mm and 111–170 mm in 2010. During summer, the dominant body length was 80–180 mm and 130–169 mm in 2000 and 2007, respectively. During autumn, the dominant body length was 60–160 mm, 100–180 mm, and 90–149 mm in 1985, 2000, and 2009, respectively. During winter, the dominant body length was 80–200 mm, 120–220 mm, and 100–200 mm in 1985, 1999, and 2010, respectively. The dominant body length decreased gradually from 1985 to 2010 (excluding spring, 2010), illustrating the “miniaturization” of the C. herzensteini population. Growth was significantly different between male and female individuals, with male individuals forming a “smaller-size type”. The sex ratio of C. herzensteini was relatively stable during spring and summer, but significantly different during autumn and winter. The diet of C. herzensteini also changed significantly from 1985 to 2010. During 1985–1986, the diet consisted primarily of Crangon affinis, Eualus sinensis and Gammaridae species. C. affinis, Engraulis japonicus, and Ammodytes personatus were dominant during 1998–2000, whereas C. affinis was the dominant prey species during 2009–2010. Thus, there was a clear decrease in dietary diversity, with a shift to benthos shrimp, particularly C. affinis, which accounted for 82.58% of the total diet (by weight) in 2010. The gastric vacuous rate also decreased in every season and the gonad developmental stage changed with each season. The distribution of C. herzensteini shifted northward and offshore and became more concentrated. The average catch per haul of C. herzensteini decreased in spring and autumn. The average catch per haul ranged from 1.44 kg h^-1 to 0.14 kg h^-1 in spring and the percentage by weight ranged from 6.53% to 1.28%. The average catch per haul ranged from 3.03 kg h^-1 to 0.26 kg h^-1 in autumn and the percentage by weight ranged from 8.00% to 0.60%. The average catch per haul increased significantly during summer, ranging from 0.18 kg h^-1 to 0.58 kg h^-1, with a percentage by weight of 0.03–0.80%. The average catch per haul was relatively stable in winter (around 1.00 kg h^-1), but the percentage by weight gradually increased during 1985–2010. Taken together, our results suggested that the population structure, diet composition, and distribution of C. herzensteini had been altered during the last three decades. To address this, it is essential to initiate measures to conserve the C. herzensteini resource.     

Dye-ligand centrifugal affinity chromatography.

A fast method for the screening of a large number of immobilized dyes for the purification or binding of proteins called dye-ligand centrifugal affinity chromatography, is described. The ease and speed of this method is demonstrated by screening 65 immobilized dyes for the binding of purified goat IgG. Two immobilized dyes (Drimarene Blue K-R and Drimarene Rubine R/K-5BL) with a high affinity for goat IgG were found to bind specifically the Fc-fragment of the IgG.     

Root mass distribution patterns under standardised conditions in species of Chionochloa and Festuca from New Zealand

The vertical biomass allocation patterns of roots grown under standardised conditions were determined for species representing the major New Zealand indigenous grass genera Chionochloa and Festuca. Ten ramets, each of 2–3 tillers from garden collections of each species were grown in irrigated vertical sand columns in a glasshouse, and harvested after 168 days. Chionochloa teretifolia, Chionochloa macra, and Chionochloa crassiusucula, characteristic of alpine environments failed to produce new roots and died. However, most of the Chionochloa taxa (Chionochloa beddiei, Chionochloa pallens, Chionochloa rigida ssp. rigida, Chionochloa rubra ssp. cuprea, Chionochloa vireta), developed extensive new roots that reached the base of the one metre sand column. Roots of Chionochloa cheesemanii and Chionochloa conspicua reached 80–90 cm depth. Two Festuca taxa (Festuca actae, Festuca luciarum) had roots to 1 m depth, and roots of Festuca coxii, Festuca matthewsii ssp. latifundii, Festuca matthewsii ssp. matthewsii, Festuca multinodis, and Festuca novae-zelandiae grew to 70–90 cm depth. The edaphic specialists (Festuca deflexa, Chionochloa spiralis, Chionochloa defracta) were all shallow rooting.Species of Festuca maintained at least 40% of the root mass in the upper 10 cm of the column and most of the Chionochloa taxa had less than 40% of root mass in the upper zone. Genotype level variation in root mass less than 10 cm deep was greater in Chionochloa than in Festuca, and least in the edaphic specialist grasses.     

DNA recognition and binding by the Euplotes telomere protein.

The 51-kDa telomere protein from Euplotes crassus binds to the extreme terminus of macronuclear telomeres, generating a very salt-stable telomeric DNA-protein complex. The protein recognizes both the sequence and the structure of the telomeric DNA. To explore how the telomere protein recognizes and binds telomeric DNA, we have examined the DNA-binding specificity of the purified protein using oligonucleotides that mimic natural and mutant versions of Euplotes telomeres. The protein binds very specifically to the 3' terminus of single-stranded oligonucleotides with the sequence (T4G4) > or = 3 T4G2; even slight modifications to this sequence reduce binding dramatically. The protein does not bind oligonucleotides corresponding to the complementary C4A4 strand of the telomere or to double-stranded C4A4.T4G4-containing sequences. Digestion of the telomere protein with trypsin generates an N-terminal protease-resistant fragment of approximately 35 kDa. This 35-kDa peptide appears to comprise the DNA-binding domain of the telomere protein as it retains most of the DNA-binding characteristics of the native 51-kDa protein. For example, the 35-kDa peptide remains bound to telomeric DNA in 2 M KCl. Additionally, the peptide binds well to single-stranded oligonucleotides that have the same sequence as the T4G4 strand of native telomeres but binds very poorly to mutant telomeric DNA sequences and double-stranded telomeric DNA. Removal of the C-terminal 15 kDa from the telomere protein does diminish the ability of the protein to bind only to the terminus of a telomeric DNA molecule.     

Imbalances in T cell subpopulations in multiple sclerosis patients.

Abnormal proportions of a distinct T cell subpopulation able to bind IgG immune complexes (T.G cells) were found in peripheral blood samples from patients with MS. About 50% of the patients examined had an overabundance of T.G cells. The possible role of these cells in the pathogenesis of MS is considered.     

Cytochrome P450 1A1 gene polymorphisms and digestive tract cancer susceptibility: a meta‐analysis

Cytochrome P450 1A1 (CYP1A1) is a phase I enzyme that regulates the metabolism of environmental carcinogens and alter the susceptibility to various cancers. Many studies have investigated the association between the CYP1A1 MspI and Ile462Val polymorphisms and digestive tract cancer (DTC) risk in different groups of populations, but their results were inconsistent. The PubMed and Embase Database were searched for case–control studies published up to 30th September, 2015. Data were extracted and pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the relationship. Totally, 39 case–control studies (9094 cases and 12,487 controls) were included. The G allele in Ile/Val polymorphism was significantly associated with elevated DTC risk with per‐allele OR of 1.24 (95% CI = 1.09–1.41, P = 0.001). Similar results were also detected under the other genetic models. Evidence was only found to support an association between MspI polymorphism and DTC in the subgroups of caucasian and mixed individuals, but not in the whole population (the dominant model: OR = 1.19, 95% CI = 0.94–1.91, P = 0.146). In conclusion, our results suggest that the CYP1A1 polymorphisms are potential risk factors for DTC. And large sample size and well‐designed studies with detailed clinical information are needed to more precisely evaluate our founding.