Dinucleotide Repeat Polymorphism Research Articles

Heme oxygenase-1 polymorphisms associate with ischemic cardiac complications and mortality in type 1 diabetes

Abstract Background/Introduction Heme oxygenase-1 (HO-1), encoded by the HMOX1 gene is a highly inducible enzyme with multiple cardiovascular protective properties. Polymorphisms of the HMOX1 gene, especially a guanine-thymine dinucleotide repeat polymorphism (GTn), affects its transcriptional activity and is associated with cardiovascular complications in the general population. Purpose We studied the association of HMOX1 polymorphisms and HO-1 plasma levels with cardiovascular complications in patients with type 1 diabetes (DM1). Methods The study population consists of patients with DM1 participating in the nationwide, multicenter Finnish Diabetic Nephropathy Study (FinnDiane). We genotyped the HMOX1 GTn repeat (n=3990), extracted from genome-wide genotyping data two single nucleotide polymorphisms (SNPs) (−413A/T upstream variant rs2071746, and +99G/C p.Asp7Asn missense variant rs2071747; n=4278), and measured the plasma HO-1 levels (n=861) from blood samples taken during a regular visit to the study center. The GTn repeats were divided into short (S) and long (L) alleles where the cutoff point was L>29 repeats. Results In men, LL genotype was associated with ischemic cardiac events (LL 22.9% vs. SS/SL 17.0%, p=0.001, see figure) and mortality (p=0.031, see figure). The association was detected also when analyzing all patients (LL 19.5% vs. SS/SL 16%, p=0.006, see figure) but not women alone (LL 15.7% vs. SS/SL 14.9%, p=0.657). For −413A/T SNP, men with AA genotype had higher odds for ischemic cardiac events (21.0% vs. 17.4%, p=0.044, see figure) but no differences in women or all together were found. There were no differences between different genotypes of +99G/C for cardiovascular complications. There was no difference in HO-1 plasma levels between different genotypes (GTn repeat, −413A/T or +99G/C). Men had significantly higher HO-1 plasma levels compared to women (3.12±1.23 ng/l vs. 2.64±1.04 ng/l, p<0.001). Interestingly, in women, higher HO-1 plasma levels were associated with cardiovascular complications and the need for antihypertensive and lipid lowering medications. Conclusions In men, but not in women LL genotype of the HMOX1 GTn repeat and AA genotype of −413A/T SNP were associated with ischemic cardiac complications and mortality. Thus, HMOX1 genotype may influence the development of cardiovascular complications in DM1 patients in a gender-dependent manner. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The Finnish Foundation for Cardiovascular ResearchFinnish State Funding for university-level research

Novel combined UGT1A1 mutations in Crigler Najjar Syndrome type I.

BackgroundUridine diphosphate‐glucuronosyl transferase 1A1 (UGT1A1), which is the major UGT1 gene product, is located on chromosome 2q37. The expression of UGT1A1 is relatively managed by a polymorphic dinucleotide repeat inside the promoter TATA box consisting of 5–8 copies of a TA repeat. A (TA) 6TAA is considered as the wild type. The A (TA) 7TAA allele has been identified as the most frequent allele in the Caucasian populations while A (TA) 8TAA allele remains the rarest allele worldwide in North Africa, including the Arab populations.MethodsThe spectrum of UGT1A1 genetic mutations in seventeen Tunisian children affected by persistent unconjugated hyperbilirubinemias is represented in addition to their relatives, notably parents, sisters, and brothers. Tunisian children, from 16 unrelated families as well as a 17th family without CN1 affected child, were originated from the West Center of Tunisia. The promoter region and coding exons of the UGT1A1 were PCR amplified, subsequently subjected to Sanger sequencing.ResultsThe frequencies of genotypes in CN1 patients were as follows (TA) (7/7) (12/17: 70.6%) and (TA) (8/8) (5/17: 29.4%). All patients harbored the c.1070A>G mutation of exon 3 (UGT1A1*16) in the homozygous state. Among relatives of our patients (n = 16), who were all heterozygotes for UGT1A1*16, 13/16 (81.25%) had a heterozygous state for UGT1A1∗1/UGT1A1∗28 or (TA) (6/7) and, 18.75% (3/16) were heterozygous for UGT1A1∗28/UGT1A1∗37 or (TA) (7/8) of the promoter polymorphisms.Conclusion UGT1A1*16 accompanied with UGT1A1*28 or UGT1A1*37 had a specific geographic and ethnic distribution for CN pathogenesis in this Tunisian cohort.

EP107: Accurate genotyping of UGT1A1 dinucleotide repeat polymorphism from targeted NGS data for the assessment of irinotecan chemotherapy adverse events

Colorectal cancer (CRC) is a leading cause of cancer-related death across the world. Irinotecan (IRI) is commonly used to treat metastatic CRC. The gene UGT1A1 encodes the enzyme responsible for the glucuronidation of SN-38, the active metabolite of IRI. Wild-type UGT1A1 contains six TA repeats [A(TA)6TAA] in its promoter region (also known as the *1 allele). Polymorphic UGT1A1 alleles with a higher number of TA repeats, such as UGT1A1 *28/(TA)7 and *37/(TA)8 alleles, cause decreased enzyme activity and are associated with severe toxicity in patients receiving IRI-based chemotherapy, for which dose reductions are recommended.

Dinucleotide (AC)n Repeat Polymorphism (rs36213840) in the Promoter Region of IL18R1 Gene and Genetic Susceptibility to Severe Malaria

Background: Cytokines are key regulator s of human immune response to malaria but polymorphisms within the regulatory or coding regions of their genes may lead to differences in expression levels which may consequently influence disease susceptibility. In this study, we characterized an adeninecytosine (AC)n dinucleotide repeat polymorphism (rs36213840) at the promoter region of the Interleukin 18 Receptor 1 (IL18R1) gene and investigated its association with severe malaria. Methods: We utilised the case-control study design to enrol a total of 207 children including 87 severe malaria cases and 120 asymptomatic controls. DNA was extracted from blood spot on filter paper using QIAamp® DNA Mini Kit (Qiagen, Hilden, Germany). Genotyping for dinucleotide repeat polymorphisms was done by PCR and capillary electrophoresis of sequenced products on ABI PRISM® 3100 DNA sequencer (PE Applied Biosystems). Results: The genotype frequencies of the dinucleotide repeats differed significantly between the two groups (χ2 = 8.69, P=0.026). We found a significantly higher frequency of the 14bp (AC)7 allele in severe malaria patients than in asymptomatic controls (odds ratio 1.945, 95% CI: 1.23 – 3.09, P = 0.005) while the frequency of the 16bp (AC)8 allele was significant higher in the asymptomatic controls than in severe cases (odds ratio 0.431, 95% CI: 0.244 – 0.761, P = 0.004). Conclusion: Results of this suggest that the 14bp (AC)7 dinucleotide repeats might be a genetic risk factor for susceptibility to severe malaria while the 16bp (AC)8 dinucleotide repeats might be a protective factor against severe malaria

SNCA REP1 and Parkinson’s disease

REP1 is a polymorphic dinucleotide repeat sequence located in the promoter region of the SNCA gene (OMIM 163890). Opinions regarding the interaction between the various REP1 alleles and Parkinson’s disease (PD) or its phenotypes have been inconsistent and have thus far not been comprehensively analyzed. In this study, we searched Medline, Embase and Cochrane databases as well as the Chinese-language Wanfang and CNKI databases using strict inclusion and exclusion criteria and conducted our analysis using Revman 5.3 software. Our search produced 28 articles describing REP1 alleles and their associated PD risks and 8 articles which discussed the relationship between REP1 variation and PD phenotypes. We found that the 265-, 269-, and 271-bp alleles of REP1 (using the nomenclature established by Xia et al.) increased the risk of PD (OR: 1.81, 1.05, 1.17; p: 0.0002, 0.003, 0.002) while the 267-bp allele decreased PD risk (OR: 0.86, p: <0.00001) when taking all populations into account. By ethnicity, we observed an obvious population heterogeneity in the effects of various alleles, where the 269-, 271-, and 273-bp alleles increased PD risk (OR: 1.06, 1.22, 1.89; p: 0.001, 0.003, 0.001) and the 267-bp allele decreased PD risk (OR: 0.85; p: <0.00001) in Caucasian populations, and the 263- and 265-bp alleles increased the risk of PD (OR: 2.22, 2.03; p: 0.03, 0.0002) and the 267- and 273-bp alleles decreased PD risk (OR: 0.90, 0.78; p: 0.02, 0.03) in Asian populations. We also determined that the 267-, 269-, and 271-bp alleles occurred the most frequently, although the frequency distribution varied among different ethnicities. Phenotypic analysis demonstrated that PD patients carrying the 271-bp allele were prone to early onset PD (OR: 1.75, p: 0.02) while the 267-bp had the opposite effect (OR: 0.81; p: 0.01).

Heme oxygenase-1 promoter region (GT)n polymorphism associates with increased neuroimmune activation and risk for encephalitis in HIV infection

BackgroundHeme oxygenase-1 (HO-1) is a critical cytoprotective enzyme that limits oxidative stress, inflammation, and cellular injury within the central nervous system (CNS) and other tissues. We previously demonstrated that HO-1 protein expression is decreased within the brains of HIV+ subjects and that this HO-1 reduction correlates with CNS immune activation and neurocognitive dysfunction. To define a potential CNS protective role for HO-1 against HIV, we analyzed a well-characterized HIV autopsy cohort for two common HO-1 promoter region polymorphisms that are implicated in regulating HO-1 promoter transcriptional activity, a (GT)n dinucleotide repeat polymorphism and a single nucleotide polymorphism (A(-413)T). Shorter HO-1 (GT)n repeats and the ‘A’ SNP allele associate with higher HO-1 promoter activity.MethodsBrain dorsolateral prefrontal cortex tissue samples from an autopsy cohort of HIV−, HIV+, and HIV encephalitis (HIVE) subjects (n = 554) were analyzed as follows: HO-1 (GT)n polymorphism allele lengths were determined by PCR and capillary electrophoresis, A(-413)T SNP alleles were determined by PCR with allele specific probes, and RNA expression of selected neuroimmune markers was analyzed by quantitative PCR.ResultsHIV+ subjects with shorter HO-1 (GT)n alleles had a significantly lower risk of HIVE; however, shorter HO-1 (GT)n alleles did not correlate with CNS or peripheral viral loads. In HIV+ subjects without HIVE, shorter HO-1 (GT)n alleles associated significantly with lower expression of brain type I interferon response markers (MX1, ISG15, and IRF1) and T-lymphocyte activation markers (CD38 and GZMB). No significant correlations were found between the HO-1 (GT)n repeat length and brain expression of macrophage markers (CD163, CD68), endothelial markers (PECAM1, VWF), the T-lymphocyte marker CD8A, or the B-lymphocyte maker CD19. Finally, we found no significant associations between the A(-413)T SNP and HIVE diagnosis, HIV viral loads, or any neuroimmune markers.ConclusionOur data suggest that an individual’s HO-1 promoter region (GT)n polymorphism allele repeat length exerts unique modifying risk effects on HIV-induced CNS neuroinflammation and associated neuropathogenesis. Shorter HO-1 (GT)n alleles increase HO-1 promoter activity, which could provide neuroprotection through decreased neuroimmune activation. Therapeutic strategies that induce HO-1 expression could decrease HIV-associated CNS neuroinflammation and decrease the risk for development of HIV neurological disease.

Insulin-like Growth Factor 1 gene polymorphism and breast cancer risk.

Insulin-like Growth Factor-1 (IGF-1) gene polymorphism has been associated with an increased risk for breast cancer. IGF-1 is a key regulator of proliferation, cell differentiation and apoptosis. It has important mitogenic and anti-apoptotic activities in normal cells and in breast cancer cells, acting synergistically with estrogen to increase neoplastic cell proliferation. This review aims to present the recent finds of IGF-1 gene polymorphism and its relationship with the risk of breast cancer through following the polymorphic dinucleotide repeat cytosine-adenine (CA) and single nucleotide polymorphisms (SNPs) by searching in the PubMed database publications focused studies published from 2010 to 2015 related to IGF-1 gene polymorphism and breast cancer risk. A growing number of studies support an association between IGF-1 gene polymorphism and breast cancer risk with conflicting results, nevertheless elucidation of the patterns of IGF-1 gene expression may permit characterization of women at high-risk for breast cancer, as well as the development of strategies for early diagnosis and efficient treatment against the disease.

The DPYSL2 gene connects mTOR and schizophrenia.

We previously reported a schizophrenia-associated polymorphic CT di-nucleotide repeat (DNR) at the 5′-untranslated repeat (UTR) of DPYSL2, which responds to mammalian target of Rapamycin (mTOR) signaling with allelic differences in reporter assays. Now using microarray analysis, we show that the DNR alleles interact differentially with specific proteins, including the mTOR-related protein HuD/ELAVL4. We confirm the differential binding to HuD and other known mTOR effectors by electrophoretic mobility shift assays. We edit HEK293 cells by CRISPR/Cas9 to carry the schizophrenia risk variant (13DNR) and observe a significant reduction of the corresponding CRMP2 isoform. These edited cells confirm the response to mTOR inhibitors and show a twofold shortening of the cellular projections. Transcriptome analysis of these modified cells by RNA-seq shows changes in 12.7% of expressed transcripts at a false discovery rate of 0.05. These transcripts are enriched in immunity-related genes, overlap significantly with those modified by the schizophrenia-associated gene, ZNF804A, and have a reverse expression signature from that seen with antipsychotic drugs. Our results support the functional importance of the DPYSL2 DNR and a role for mTOR signaling in schizophrenia.

Polymorphic GT dinucleotide repeat in the PIK3CA gene and risk of colorectal cancer

Activated PI3K generate PIP3 to trigger different signaling pathways which regulate a number of cellular functions including cell survival, apoptosis, proliferation and motility. Mutations in many cancers were discovered in the gene encoding the PI3K catalytic subunit, PIK3CA. To date, there has been no report on the association between polymorphism of PIK3CA gene microsatellites and risk of colorectal cancer. In this study, we investigate the relation between the GT dinucleotide repeat in intron 1 of the PIK3CA gene and colorectal cancer risk. A case-control study of 103 colorectal cancer patients and 150 controls was conducted in Iranian people. The results of our study demonstrate that PIK3CA gene allele distribution in Iranian population varies between 13 and 20 repeats. Here we demonstrate that individuals who carry alleles shorter than 17 GT repeat are at higher risk of developing colorectal cancer (OR = 4.0, p= 0), by contrast, those individuals with two alleles longer than 16 GT repeats are at a significantly lower risk of developing colorectal cancer (OR = 0.12, p= 0). This result suggests polymorphic GT repeat of PIK3CA gene may be a potential predictive marker of colorectal cancer risk in Iranian population.

A thymine-adenine dinucleotide repeat polymorphism near IL28B is associated with spontaneous clearance of hepatitis C virus.

Genome-wide association studies have revealed several single-nucleotide polymorphisms around interleukin 28B (IL28B) that are strongly associated with hepatitis C virus (HCV) clearance. However, their predictive value is not perfect, which suggests that other genetic factors may also be involved in HCV clearance. We previously reported a wide variation in the length of a thymine-adenine (TA) dinucleotide repeat in the promoter region of IL28B and that the transcriptional activity of the promoter increased gradually in a TA repeat length-dependent manner. We determined the length of the TA repeats of 1,060 Japanese and 201 African-American samples to investigate the relation to spontaneous HCV clearance. The distribution of the TA repeats greatly differed between the two ethnicities. The variation ranged from 10 to 18 repeats, and the most frequent allele, 12, accounted for over 80% for Japanese. The African-American data showed a gently sloping distribution, and the allele with six repeats was detected only in the African-American sample. The TA repeats 11 or greater were correlated with spontaneous clearance. Multiple logistic regression analysis extracted the genotype of the TA repeats as an independent factor in both the Japanese [p = 0.0004, odds ratio (OR) = 13.02 95% confidence interval (CI) = 2.59-237.0] and African-American (p = 0.027, OR = 3.70 95% CI = 1.16-11.8) populations. A long TA repeat in the promoter region of IL28B was associated with spontaneous HCV clearance. Although its efficacy may be limited in Japanese population because of its allele distribution, this novel genetic factor will be useful for predicting HCV clearance especially for the African Americans.

Functional variants in DPYSL2 sequence increase risk of schizophrenia and suggest a link to mTOR signaling.

Numerous linkage and association studies by our group and others have implicated DPYSL2 at 8p21.2 in schizophrenia. Here we explore DPYSL2 for functional variation that underlies these associations. We sequenced all 14 exons of DPYSL2 as well as 27 conserved noncoding regions at the locus in 137 cases and 151 controls. We identified 120 variants, eight of which we genotyped in an additional 729 cases and 1542 controls. Several were significantly associated with schizophrenia, including a three single-nucleotide polymorphism (SNP) haplotype in the proximal promoter, two SNPs in intron 1, and a polymorphic dinucleotide repeat in the 5′-untranslated region that alters sequences predicted to be involved in translational regulation by mammalian target of rapamycin signaling. The 3-SNP promoter haplotype and the sequence surrounding one of the intron 1 SNPs direct tissue-specific expression in the nervous systems of Zebrafish in a pattern consistent with the two endogenous dpysl2 paralogs. In addition, two SNP haplotypes over the coding exons and 3′ end of DPYSL2 showed association with opposing sex-specific risks. These data suggest that these polymorphic, schizophrenia-associated sequences function as regulatory elements for DPYSL2 expression. In transient transfection assays, the high risk allele of the polymorphic dinucleotide repeat diminished reporter expression by 3- to 4-fold. Both the high- and low-risk alleles respond to allosteric mTOR inhibition by rapamycin until, at high drug levels, allelic differences are eliminated. Our results suggest that reduced transcription and mTOR-regulated translation of certain DPYSL2 isoforms increase the risk for schizophrenia.

Association between the lengths of GT dinucleotide repeat in the PIK3CA gene with breast cancer risk.

The phosphatidylinositol 3-kinase (PI3 K)/Akt signaling pathway is one of the most commonly mutated pathways in breast cancer. To date, there has been no study on polymorphism of phosphatidylinositol-3,4-bisphosphonate 3-kinase, catalytic subunit alpha (PIK3CA) gene microsatellites and their link with breast cancer risk. In the present study, we investigate the guanine-thymine (GT) dinucleotide repeat polymorphism in intron 1 of PIK3CA gene in a cohort of 200 breast cancer patients and 200 healthy individuals and its link to the risk of developing breast cancer. The results of this study demonstrate that PIK3CA gene allele distribution in Isfahan population varies between 13 and 20 repeats. GT14 and GT16 were the most common allele present in patients, and GT17 was the most common allele in controls. Women with one or two alleles shorter than 17 GT repeat have a significantly higher risk of developing breast cancer [Odds ratio (OR) 3.6, p = 0.00001 and OR 3.98, p = 0.000001, respectively], in contrast, women with one or two alleles longer than 16 are at lower risk of breast cancer. This result suggests a potential role for this microsatellite as a predictive marker of breast cancer risk in Iranian women.

Abstract 2394: Impact of epidermal growth factor receptor (EGFR) gene intron 1 dinucleotide CA repeat polymorphism on protein expression and clinical outcome in oral cavity squamous cell carcinoma.

Abstract Epidermal growth factor receptor (EGFR) is one of the four members of the ErbB receptor family and has been shown to play a key role in tumorigenesis of many human cancers including oral cavity squamous cell carcinoma (OSCC). Previous studies have observed a significant relationship between EGFR overexpression and poor outcomes in head and neck squamous cell carcinoma (HNSCC) including OSCC. Elevated EGFR levels have primarily been attributed to enhanced transcriptional activity, rather than amplification of the gene. Since the EGFR intron 1 polymorphic CA dinucleotide repeats has been suggested to affect EGFR transcription efficiency, the present study was designed to explore the relationship between this CA repeats polymorphism, gene copy number and protein levels in Taiwanese OSCC. A total of 194 OSCCs were examined for EGFR protein overexpression using immunohistochemistry and for copy number using a fluorescence in situ hybridization (FISH) assay. DNAs from peripheral blood of 164 OSCC patients were also available for EGFR intron 1 CA dinucleotide repeats analysis. Overexpression and increased gene copy numbers of EGFR were found in 101 (52.06%) and 59 (30.41%) cases, respectively. The length of EGFR CA repeats were not associated with EGFR protein expression (p = 0.261) while the copy number was strongly related to protein overexpression (p &amp;lt; 0.001). EGFR protein overexpression was associated with young age (p = 0.036), tumor differentiation (p &amp;lt; 0.001) and lymph node metastasis (p = 0.028). EGFR gene copy number was also associated with young age (p = 0.009), tumor cell differentiation (p = 0.002), tumor depth (p = 0.001), lymph node metastasis (p = 0.051) and bone invasion (p = 0.003). However, the length of EGFR CA repeats was not associated with clinicopathologic factors. Patients with EGFR overexpression in their tumors were found to have significant poorer disease-free survival (DFS) (p = 0.026, log-rank test) and overall survival (OS) (p = 0.019, log-rank test) than those without overexpression. Patients with CA repeats SS form (both alleles &amp;lt; 19 repeats) had significantly shorter DFS and OS than those with SL and LL forms (both alleles ≥ 19 repeats) (p = 0.039 and 0.018 for DFS and OS, respectively). On the other hand, the association between an increase in EGFR gene copies and DFS or OS was insignificant. In summary, our current findings confirm that EGFR protein overexpression is closely related to EGFR copy number; but, do not support the role of CA repeats as an EGFR expression regulator. On the other hand, the length of CA repeats was significantly associated with both DFS and OS. Citation Format: Shiang-Fu Huang, I-How Chen, Chun-Ta Liao, Hung-Ming Wang, Ling-Ling Hsieh. Impact of epidermal growth factor receptor (EGFR) gene intron 1 dinucleotide CA repeat polymorphism on protein expression and clinical outcome in oral cavity squamous cell carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2394. doi:10.1158/1538-7445.AM2013-2394

Genetic variants of FOXP3 influence graft survival in kidney transplant patients

FOXP3(+) regulatory T cells (Treg) play a role in controlling alloreactivity. It has been shown that short (GT)n dinucleotide repeats (≤(GT)15; S) in the promoter region of the FOXP3 gene enhance the promoter activity when compared to long (GT)n repeats (≥(GT)16; L). The present study retrospectively investigated the influence of this (GT)n FOXP3 gene polymorphism on renal allograft survival. A total of 599 consecutive first-time kidney transplant patients (median follow-up time 7.7 years) were subdivided according to their FOXP3 genotype into the S-genotype group (SG) and the L-genotype group (LG). The SG was superior to the LG in both general graft survival censored for death (logrank test, p=0.013) and graft survival following acute rejection (p=0.021). Multivariate analysis defined the (GT)n FOXP3 dinucleotide repeat polymorphism as an independent factor and confirmed an advantage for the SG in renal allograft survival (HR=0.67, 95% CI 0.48-0.94, p=0.02). This gene association study identified a beneficial effect of FOXP3 genetic variants on graft survival in kidney transplant patients.

Polymorphic CT dinucleotide repeat in the GATA3 gene and risk of breast cancer in Iranian women

GATA3 is an enriched transcription factor in mammary epithelium. To date, there has been no study on the relationship between microsatellites in the GATA3 gene and breast cancer risk. In this study, we investigated the existence of polymorphisms in the cytosine-thymine (CT) dinucleotide repeat in intron 3 of the GATA3 gene and its association with breast cancer risk. A case-control study of 206 breast cancer patients and 262 controls was conducted in Iranian women. Several different CT repeat alleles of GATA3 were detected in both the patients and controls. The frequencies of 17 and 18 alleles in patients were significantly lower than controls. Our findings demonstrate that women who carry 17-CT (OR = 0.5; p = 0.003) or 18-CT (OR = 0.41, p = 0.02) alleles of GATA3 gene are at lower risk of developing breast cancer. The highest protection against breast cancer was observed with heterozygotes of 16/17 repeats (OR = 0.12, p = 0.02). Also, the presence of the 17-CT allele has a positive relation with estrogen receptor expression. However, we found that the allelic length of GATA3 polymorphisms had no significant effect on the age onset or grade of the disease, as well as the expression of progesterone receptors and HER2.

Association of a cytosine-adenine repeat polymorphism in the estrogen receptor &amp;lt;i&amp;gt;β&amp;lt;/i&amp;gt; gene with occurrence and severity of rheumatoid arthritis

We investigated the influence of the cytosine-adenine (CA) dinucleotide repeat polymorphism in intron 6 of estrogen receptor β (ERβ) gene on rheumatoid arthritis (RA) risk. One hundred and ninety-three RA patients and 77 control subjects with osteoarthritis (OA) were recruited. The CA repeat polymorphism was assayed by a dye-terminator cycle sequencing analysis. No statistically significant difference in the mean number of CA repeats between the RA and OA patients was observed (RA: 21.47, OA: 21.23, P = 0.324). The alleles were categorized according to the number of repeats: short (S, ≦21) and long (L, ≧22), in which the genotypes SS, SL, and LL were observed. No significant differences were observed for the allele and genotype distributions of this polymorphism in both patient groups. The RA patients were classified according to RA severity: mild (least erosive disease) and severe (more erosive and mutilating disease). Again, no significant difference in genotype frequency between these groups was observed, even after stratifying by sex. The present study indicates that additional studies are needed to clarify the roles of this polymorphism, estrogen, and ER in the development of autoimmune diseases.

Microsatellite polymorphism in the heme oxygenase-1 gene promoter and the risk of psoriasis in Taiwanese

Psoriasis is a chronic disease characterized by inflammation of the skin. The expression of heme oxygenase-1 (HO-1), the rate-limiting enzyme involved in heme degradation, correlates well with the severity of psoriasis, and is a heritable trait. This study aimed to assess the role of (GT)(n) dinucleotide repeat polymorphisms in the promoter region of the HO-1 gene in Chinese-Taiwanese patients with psoriasis. In total, 288 patients with psoriasis and 542 control subjects were analyzed for the presence of the HO-1 microsatellite polymorphism by using polymerase chain reaction. The alleles were classified as the S and L alleles according to the number of (GT)(n) repeats, with the alleles with ≤26 repeats designated as S and alleles with ≥27 repeats designated as L alleles. The subjects were then classified as having S/S, S/L, or L/L genotypes according to each of their HO-1 alleles. No significant difference was observed in either the genotype or allele distribution between the patients and healthy controls. However, the average number of repeats of both alleles in psoriasis patients with late disease onset was lower than that of psoriasis patients with early disease onset (26.7±3.2 vs. 27.5±3.4; P=0.043, adjusted for age and sex), but the difference was not significant after additional adjustment for body mass index, smoking, diabetes, and hypertension (P=0.189). Our results suggest that the HO-1 microsatellite polymorphism may not contribute to the genetic background of psoriasis in Chinese-Taiwanese patients.

Association between estrogen receptor-β dinucleotide repeat polymorphism and incidence of femoral fracture

Estrogens are thought to play an important role in bone metabolism through estrogen receptors (ER). Dinucleotide (cytosine-adenine, CA) repeat polymorphism in the human ER-β gene (ESR2) has been reported to be associated with bone mineral density. We aimed to further elucidate the importance of this polymorphism in the pathogenesis of osteoporosis by examining its association with the incidence of femoral fracture. Deoxyribonucleic acids extracted from the renal cortex of 1489 consecutive Japanese autopsies (799 male, mean age 79years, 690 female, mean age 82years) with complete clinical/pathological data were enrolled in the study. ESR2 CA repeat polymorphism was determined by polymerase chain reaction using fluorescein-labeled primers. The presence or absence of femoral fracture during each subject's lifetime was determined by thorough examination of the clinical record. Incidence of femoral fracture in subjects bearing at least one allele of 20 CA repeats (4/132, 3.0%) was significantly lower than in those without this allele (127/1357, 9.4%, P=0.0098). After adjustments for age and sex, logistic regression analysis revealed that having no allele of 20 CA repeats was an independent risk factor of femoral fracture [adjusted odds ratio (OR) 3.875, 95% confidence interval (CI) 1.392-10.788, P=0.0095], which was emphasized among women (adjusted OR 6.360, 95% CI 1.520-26.618, P=0.0133). Japanese subjects, especially women, bearing at least one allele of 20 CA repeats in the ESR2 may have a lower risk of femoral fracture than those without it, suggesting this polymorphism plays a role in bone metabolism.

Abstract B11: EGFR polymorphism as a predictor of clinical outcome in advanced lung cancer patients treated with EGFR-TKI

Abstract Background: Mutations in the epidermal growth factor receptor (EGFR) have been confirmed as predictors of efficacy for EGFR-tyrosine kinase inhibitors (TKIs). We investigated whether polymorphisms of the EGFR gene were associated with clinical outcome in NSCLC patients treated with EGFR-TKI. Methods: A polymorphic dinucleotide repeat (CA simple sequence repeat 1 [CA-SSR1]) in intron one and single nucleotide polymorphisms in the promoter region (SNP -216 GG or GT) were evaluated in 71 NSCLC patients by PCR-RFLP and DNA sequencing. Genetic polymorphisms were correlated with clinical outcomes of EGFR-TKIs. Results: SNP-216G/T polymorphisms were associated with the efficacy of EGFR-TKI. The response rate for the SNP-216G/T was significantly higher than that for the GG (62.5% vs. 27.4%, P=0.044). SNP-216G/T genotype was also associated with longer progression-free survival compared with GG genotype (16.7 months vs. 5.1 months, P=0.005). However, Genotypes for the CA-SSR1 was not associated with the efficacy of EGFR-TKI. Conclusions: SNP-216G/T polymorphism is potential predictor for clinical outcome in NSCLC patients treated with EGFR-TKI.

EGFRPolymorphism as a Predictor of Clinical Outcome in Advanced Lung Cancer Patients Treated withEGFR-TKI

PurposeMutations in the epidermal growth factor receptor (EGFR) have been confirmed as predictors of the efficacy of treatment with EGFR-tyrosine kinase inhibitors (TKIs). We investigated whether polymorphisms of the EGFR gene were associated with clinical outcomes in non-small cell lung cancer (NSCLC) patients treated with EGFR-TKI.Materials and MethodsA polymorphic dinucleotide repeat in intron 1 [CA simple sequence repeat in intron 1(CA-SSR1)] in intron 1 and single nucleotide polymorphisms (SNP-216) in the promoter region of the EGFR gene were evaluated in 71 NSCLC patients by restriction fragment length polymorphism and DNA sequencing. The relationship between genetic polymorphisms and clinical outcomes of treatment with EGFR-TKIs was evaluated.ResultsSNP-216G/T polymorphisms were associated with the efficacy of EGFR-TKI. The response rate for the SNP-216G/T tended to be higher than that for G/G (62.5% vs. 27.4%, p=0.057). The SNP-216G/T genotype was also associated with longer progression-free survival compared with the GG genotype (16.7 months vs. 5.1 months, p=0.005). However, the length of CA-SSR1 was not associated with the efficacy of EGFR-TKI.ConclusionSNP-216G/T polymorphism was a potential predictor of clinical outcomes in NSCLC patients treated with EGFR-TKI.