Association of the progesterone receptor gene with endometrial cancer risk in a Chinese population

BACKGROUND:

Single nucleotide polymorphisms (SNPs) in the progesterone receptor (PGR) gene have been associated with the risk of endometrial cancer. However, to the authors' knowledge, no study to date has systematically evaluated the role of the PGR gene in endometrial carcinogenesis.

METHODS:

Exposure information and DNA samples collected in the Shanghai Endometrial Cancer Study, a population‐based case‐control study of 1204 incident cases and 1212 age‐ and frequency‐matched population controls, were used in this study. Seven tag SNPs were identified for the PGR gene plus the 5‐kilobase (kb) flanking regions using the Han Chinese data from the HapMap project with a pairwise correlation coefficient (r²) ≥ 0.90. These 7 SNPs captured 92% of SNPs in the region with a pairwise r² ≥ 0.90 or 100% of SNPs with a pairwise r² ≥ 0.80. Genotyping of polymorphisms was performed by using the Affymetrix MegAllele Targeted Genotyping System. A logistic regression model was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS:

Of 7 tag SNPs that were assessed, 2 polymorphisms in the 3′ flanking region of the PGR gene, reference SNP identification number (rs) 11224561 (rs11224561) and rs471767, were associated with the risk of endometrial cancer. The cytosine/cytosine (CC) genotype of SNP rs11224561 was associated with decreased risk (OR, 0.68; 95% CI, 0.50‐0.92) compared with the thymine/thymine (TT) genotype. Carrying the guanine (G) allele of the rs471767 SNP also was associated with decreased risk, although the association was not statistically significant (OR, 0.78, 95%CI, 0.59‐1.04 and OR, 0.32, 95%CI, 0.03‐3.05 for the adenine [A]G and GG genotypes, respectively, compared with the homozygote AA).

CONCLUSIONS:

The current findings suggested that polymorphisms in the 3′ flanking region of the PGR gene may be associated with the risk of endometrial cancer. Cancer 2009. © 2009 American Cancer Society.     

Progesterone receptor variation and risk of ovarian cancer is limited to the invasive endometrioid subtype: results from the Ovarian Cancer Association Consortium pooled analysis

There is evidence that progesterone plays a role in the aetiology of invasive epithelial ovarian cancer. Therefore, genes involved in pathways that regulate progesterone may be candidates for susceptibility to this disease. Previous studies have suggested that genetic variants in the progesterone receptor gene (PGR) may be associated with ovarian cancer risk, although results have been inconsistent. We have established an international consortium to pool resources and data from many ovarian cancer case-control studies in an effort to identify variants that influence risk. In this study, three PGR single nucleotide polymorphisms (SNPs), for which previous data have suggested they affect ovarian cancer risk, were examined. These were +331 C/T (rs10895068), PROGINS (rs1042838), and a 3' variant (rs608995). A total of 4788 ovarian cancer cases and 7614 controls from 12 case-control studies were included in this analysis. Unconditional logistic regression was used to model the association between each SNP and ovarian cancer risk and two-sided P-values are reported. Overall, risk of ovarian cancer was not associated with any of the three variants studied. However, in histopathological subtype analyses, we found a statistically significant association between risk of endometrioid ovarian cancer and the PROGINS allele (n=651, OR=1.17, 95% CI=1.01-1.36, P=0.036). We also observed borderline evidence of an association between risk of endometrioid ovarian cancer and the +331C/T variant (n=725 cases; OR=0.80, 95% CI 0.62-1.04, P=0.100). These data suggest that while these three variants in the PGR are not associated with ovarian cancer overall, the PROGINS variant may play a modest role in risk of endometrioid ovarian cancer.     

Association of the progesterone receptor gene with breast cancer risk: a single-nucleotide polymorphism tagging approach.

Association studies on susceptibility to breast cancer using single nucleotide polymorphisms (SNP) in the progesterone receptor (PGR) gene have been previously published, but the results have been inconclusive. We used a comprehensive SNP-tagging approach to search for low-penetrance susceptibility alleles in a study of up to 4,647 cases and 4,564 controls, in a two-stage study design. We identified seven tagging SNPs using genotype data from the National Institute of Environmental Health Sciences (NIEHS) Environmental Genome Project and typed these, and an additional three SNPs, in 2,345 breast cancer cases and 2,284 controls (set 1). Three SNPs showed no evidence for association and were not studied further, whereas seven SNPs (rs11571171, rs7116336, rs660149, rs10895068, rs500760, rs566351, and rs1042838) exhibited significant associations at P < 0.1 using either a heterogeneity or trend test and progressed to be genotyped in set 2. After both stages, only one SNP was significantly associated with an increased risk of breast cancer - the PGR-12 (rs1042638) V660L valine to leucine polymorphism [VL heterozygotes (odds ratio, 1.13; 95% confidence interval, 1.03-1.24) and the LL homozygotes (odds ratio, 1.30; 95% confidence interval, 0.98-1.73), P(het) = 0.008, P(trend) = 0.002]. Similar estimates were obtained in a combined analysis of our data with those from three other published studies. We conclude that the 660L allele may be associated with a moderately increased risk of breast cancer, but that other common SNPs in the PGR gene are unlikely to be associated with a substantial risk of breast cancer.     

Progesterone receptor polymorphisms and risk of breast cancer: results from two Australian breast cancer studies

Association studies aimed at identifying breast cancer susceptibility variants in the progesterone receptor (PGR) gene have been previously reported in the literature with conflicting results, ranging from a protective effect conferred by the PROGINS allele in German Caucasian women, to an increased risk for the leucine variant of the Val660Leu (rs1042838) polymorphism in East Anglian cases. We report the results of genotype and haplotype analyses of five PGR polymorphisms, +44C/T (rs518162), +331G/A (rs10895068), V660L (rs1042838), H770H (rs1042839) and Q886Q (rs500760), conducted on 1,847 Australian breast cancer cases (including 276 cases from a cohort of multiple-case breast cancer families) and 833 controls. Genotype and haplotype analyses of the five polymorphisms showed no evidence of an association with breast cancer (p > 0.3). We also conducted a meta-analysis of the V660 L (rs1042838) polymorphism on our and six other published studies including 10,205 cases and 11,320 controls. Compared to the VV homozygotes, VL heterozygotes and LL homozygotes were associated with a non-significant increased risk for breast cancer [Odds ratio (OR)_VL, 1.06; 95% confidence intervals (95% CI), 0.97–1.15, OR_LL, 1.05; 95% CI, 0.75–1.49]. Analysis of a per-leucine allele risk under a codominant model, however, suggested a significant leucine-allele dose effect, OR_per-L, 1.07; 95% CI, 1.02–1.13, p = 0.01. We conclude that the leucine allele of the V660L SNP may be associated with a small increase in breast cancer risk, while the other four PGR SNPs, +44C/T (rs518162), +331G/A (rs10895068), H770H (rs1042839) and Q886Q (rs500760), do not substantially increase breast cancer risk.     

Pathway-Affecting Single Nucleotide Polymorphisms (SNPs) in RPS6KA1 and MBIP Genes are Associated with Breast Cancer Risk

Background: Genetic mutations and polymorphisms play an important role in the transformation of primary cells to malignant cells as it may lead to disturbance of vital pathways regulating cell cycle, DNA damage repair, and apoptosis. In this study, we genotyped single nucleotide polymorphisms (SNPs) which were predicted to affect certain pathways and to increase the risk of breast cancer. Methods: The study included 81 Saudi breast cancer patients and 100 matching healthy controls from the Eastern Province in Saudi Arabia. The following SNPs (rs3168891, rs2899849, rs2230394, rs2229714) were then genotyped by TaqMan genotyping assay and the allele and genotype distribution was compared. Results: The minor allele frequency of the following SNPs (rs3168891, rs2899849, rs2230394, rs2229714) was T=0.17, A=0.28, A=0.22, and G=0.16 respectively. The G allele of the SNP rs3168891 was significantly associated with increased breast cancer risk (P = 0.00001) while the T allele of the same locus was associated with reduced risk of breast cancer in both heterozygous and homozygous states. The T allele of SNP rs2229714 which is located in the RPS6KA1 gene was also significantly associated with the increased risk of breast cancer. However, the rs2899849 SNP located in the Integrin beta-1 (ITGB1) gene was not associated with the increased risk of breast cancer in our study population. Haplotype analysis revealed the presence of three risk haplotypes that increases the risk of breast cancer (TGGT, TGTA, GATA). Conclusion: We showed that three, previously untested, SNPs are associated with increased risk of breast cancer in our population.  This may be added to the list of factors involved in breast cancer risk assessment studies. The benefit and the utility of the in-silico prediction of disease risk factors and their genetic association had been demonstrated in this study, yet the predicted risk alleles have to be tested in clinical studies.     

Vitamin D receptor polymorphisms in patients with cutaneous melanoma

The vitamin D receptor (VDR) gene has been associated with cancer risk, but only a few polymorphisms have been studied in relation to melanoma risk and the results have been inconsistent. We examined 38 VDR gene single nucleotide polymorphisms (SNPs) in a large international multicenter population-based case-control study of melanoma. Buccal DNAs were obtained from 1,207 people with incident multiple primary melanoma and 2,469 with incident single primary melanoma. SNPs with known or suspected impact on VDR activity, haplotype tagging SNPs with ≥ 10% minor allele frequency in Caucasians, and SNPs reported as significant in other association studies were examined. Logistic regression was used to calculate the relative risks conferred by the individual SNP. Eight of 38 SNPs in the promoter, coding, and 3' gene regions were individually significantly associated with multiple primary melanoma after adjusting for covariates. The estimated increase in risk for individuals who were homozygous for the minor allele ranged from 25 to 33% for six polymorphisms: rs10875712 (odds ratios [OR] 1.28; 95% confidence interval (CI), 1.01-1.62), rs4760674 (OR 1.33; 95% CI, 1.06-1.67), rs7139166 (OR 1.26; 95%CI, 1.02-1.56), rs4516035 (OR 1.25; 95%CI, 1.01-1.55), rs11168287 (OR 1.27; 95%CI, 1.03-1.57) and rs1544410 (OR 1.30; 95%CI, 1.04-1.63); for two polymorphisms, homozygous carriers had a decreased risk: rs7305032 (OR 0.81; 95%CI 0.65-1.02) and rs7965281 (OR, 0.78; 95%CI, 0.62-0.99). We recognize the potential false positive findings because of multiple comparisons; however, the eight significant SNPs in our study outnumbered the two significant tests expected to occur by chance. The VDR may play a role in melanomagenesis.     

Association of progesterone receptor gene (PGR) variants and breast cancer risk in African American women

Prolonged exposure to combined hormone replacement therapy (estrogen plus progestin) increases a woman’s risk of breast cancer, whereas estrogen-only hormone replacement therapy does not. This suggests that progesterone may play a role in breast carcinogenesis. Association studies have reported inconsistent relationships between progesterone receptor gene variants and breast cancer. A population-based case–control study in three counties of the Philadelphia Metropolitan area was undertaken. We evaluated 8 PGR candidate SNPs and 18 PGR tagging SNPS in 487 breast cancer cases and 843 controls using multivariable logistic regression with adjustment for combined hormone replacement therapy use. Separate analyses were conducted for European Americans (EA: 399 cases, 490 controls) and African Americans (AA: 88 cases, 353 controls). In EAs, no significant associations were observed with the investigated PGR variants. In AAs, two tagging SNPs (rs590688 and rs10895054) were statistically significantly associated with breast cancer. For rs590688, each addition of the C allele was protective compared to the G allele (OR = 0.56, 95 % CI 0.39–0.82, p value 0.003, corrected p value 0.03). For rs10895054, each addition of the T allele increased the risk of breast cancer compared to the A allele nearly threefold (OR = 2.9, 95 % CI 1.47–6.02, p value 0.002, corrected p value 0.04). Three haplotype blocks, all containing rs590688, were found to be significantly associated with breast cancer risk. Environmental exposures, namely parity and obesity modified the effect of both SNPs on breast cancer risk in EA. This is the first study to find an association between two PGR variants and breast cancer in AA women. These results suggest that studies of PGR variants in other non-White populations may reveal additional cancer associations of interest.     

雌激素受体α基因单核苷酸多态性与中国陕西地区汉族人群子宫内膜癌的相关性研究

目的:探讨雌激素受体α（estrogen receptor α,ERα）基因exon 4 的A908G、C926T、G933A、C975G 4个单核苷酸多态性（single nucleotide polymorphisms,SNPs）与子宫内膜癌易感性的相关性。方法:基于人群的病例-对照研究,通过PCR产物直接测序法鉴定中国陕西地区汉族89例子宫内膜癌与115例良性病变组织的这4个SNPs的基因型,采用Logistic回归模型分析两组基因型与等位基因频率的分布,确定SNP位点基因型与子宫内膜癌临床病理特征的相关性。结果:所有组织的ERα基因3个位点SNPs 均呈A908A、C926C、G933G野生型;而exon 4 C975G 位点SNP呈三种基因型形式,其频率分布在两组均达到Hardy-Weinberg遗传平衡(P>0.05),说明具有群体代表性。两组975G等位基因的发生频率分别为48.9%和51.7%,均＞1%,说明均存在exon 4 位点C975G SNP。两组间基因型与等位基因频率均无显著性差异（P>0.05）,说明位点C975G SNP与子宫内膜癌的危险性无关。ERα基因C975G SNP基因型与临床病理特征无相关性（P>0.05）。结论:首先在中国人子宫内膜癌和对照组中发现ERα基因exon 4 突变975G等位基因,发生频率分别为48.9%和51.7%,均＞1%,但C975G SNP与子宫内膜癌的危险性无关;且提示ERα基因的多态性可能具有肿瘤类型和种族的特异性。首先在中国人子宫内膜癌和对照组中未发现ERα基因exon 4位点A908G、C926T、G933A 3个SNPs,表明这些位点多态性在子宫内膜癌病人中并不常见。     

Genetic variants on chromosome 5p12 are associated with risk of breast cancer in African American women: the Black Women’s Health Study

Two single nucleotide polymorphisms (SNPs), rs4415084, and rs10941679 on chromosome 5p12 were associated with risk of breast cancer in a recent genome-wide association study (GWAS) of women of European ancestry. Both SNPs are located in a large high-LD region and the causal variant(s) are still unknown. We conducted a nested case–control study in a cohort of African American women to replicate and narrow the region carrying the causal variant(s). We evaluated 14 tagging SNPs in a 98 kb LD block surrounding the index SNPs in 886 breast cancer cases and 1,089 controls from the Black Women’s Health Study. We used the Cochran–Armitage trend test to assess association with breast cancer risk. Odds ratios were derived from logistic regression analyses adjusted for potential confounders including percent European admixture. We confirmed the reported association of rs4415084 SNP with overall risk of breast cancer (P = 0.06), and, as in the original study, observed a stronger association with estrogen receptor positive tumors (P = 0.03). We identified four other SNPs (rs6451770, rs12515012, rs13156930, and rs16901937) associated with risk of breast cancer at the nominal alpha value of 0.05; all of them were located in a 59 kb HapMap YRI LD block. After correction for multiple testing, the association with SNP rs16901937 remained significant (P permutated = 0.038). The G allele was associated with a 21% increased risk of breast cancer overall and with a 32% increase in tumors positive for both estrogen and progesterone receptors. The present results from an African ancestry (AA) population confirm the presence of breast cancer susceptibility genetic variants in the chromosome 5p12 region. We successfully used the shorter range of LD in our AA sample to refine the localization of the putative causal variant.     

Estrogen receptor alpha haplotypes and breast cancer risk in older Caucasian women

Life-long exposure to estrogen is an established risk factor for breast cancer development. The underlying mechanism has been suggested to be the binding of estrogen-to-estrogen receptors in mammary tissue, which in turn promotes the proliferation and differentiation of breast tissue. Polymorphisms and haplotypes in estrogen receptor alpha (ESR1) have been reportedly associated with breast cancer risk; however, the results are not fully consistent. In this study, we investigated breast cancer risk associated with genotypes and haplotypes resulting from four ESR1 single nucleotide polymorphisms (SNPs), rs746432, rs2234693, rs9340799, and rs1801132. Genotyping has been performed on 393 breast cancer cases and 790 randomly selected controls in 1,183 Caucasian women over age 65 from the Study of Osteoporotic Fractures (SOF). We observed an allelic protective effect for SNP rs9340799 with an estimated odds ratio (OR) of 0.82 (95% CI = 0.68–1.00; P = 0.04) after adjustment for age, BMI and hip BMD. A protective effect of this SNP has been reported before in several different studies. We did not replicate the previously reported C–C–A–G haplotype association to breast cancer—the C–C–A–G haplotype from these SNPs was rare in this study (estimated frequency below 0.001% in cases and controls). No other statistically significant associations were observed between ESR1 haplotypes from the same four SNPs and the risk of breast cancer in older Caucasian women.     

A functional variant at the miR-184 binding site in TNFAIP2 and risk of squamous cell carcinoma of the head and neck

Although the role of TNFAIP2 is still unclear, it is an important gene involved in apoptosis, and there are single-nucleotide polymorphisms (SNPs) at its microRNA (miRNA)-binding sites that could modulate miRNA target gene function. In this study, we evaluated associations of four selected SNPs (rs8126 T > C, rs710100 G > A, rs1052912 G > A and rs1052823 G > T) in the miRNA-binding sites of the 3' untranslated region (UTR) with squamous cell carcinoma of the head and neck (SCCHN) risk in 1077 patients with SCCHN and 1073 cancer-free controls in a non-Hispanic White population. We found that, compared with the rs8126 TT genotype, the variant C allele were associated with increased SCCHN risk in an allele dose-response manner (adjusted odds ratio = 1.48 and 95% confidence interval = 1.06-2.05 for CC, respectively; P(trend) = 0.009). No significant associations were seen for the other three SNPs (rs710100 G > A, rs1052912 G > A and rs1052823 G > T). Additionally, we identified that the rs8126 T > C SNP is within the miR-184 seed binding region in the 3' UTR of TNFAIP2. Further functional analyses showed that the rs8126 variant C allele led to significantly lower luciferase activity, compared with the T allele. In the genotype-phenotype correlation analysis of peripheral blood mononuclear cells from 64 SCCHN patients, the rs8126 CC genotype was associated with reduced expression of TNFAIP2 messenger RNA. Taken together, these findings indicate that the miR-184 binding site SNP (rs8126 T > C) in the 3' UTR of TNFAIP2 is functional by modulating TNFAIP2 expression and contributes to SCCHN susceptibility. Larger replication studies are needed to confirm our findings.     

Single nucleotide polymorphisms associated with risk for contralateral breast cancer in the Women's Environment, Cancer, and Radiation Epidemiology (WECARE) Study

Introduction

Genome-wide association studies, focusing primarily on unilateral breast cancer, have identified single nucleotide polymorphisms (SNPs) in a number of genomic regions that have alleles associated with a significantly increased risk of breast cancer. In the current study we evaluate the contributions of these previously identified regions to the risk of developing contralateral breast cancer. The most strongly disease-associated SNPs from prior studies were tested for association with contralateral breast cancer. A subset of these SNPs, selected upon their main effects on contralateral breast cancer risk was further evaluated for interaction with treatment modalities and estrogen receptor (ER) status.

Methods

We genotyped 21 SNPs in 708 women with contralateral breast cancer and 1394 women with unilateral breast cancer who serve as the cases and controls in the Women's Environment, Cancer and Radiation Epidemiology (WECARE) Study. Records of treatment and ER status were available for most of WECARE Study participants. Associations of SNP genotypes and risk for contralateral breast cancer were calculated with multivariable adjusted conditional logistic regression methods.

Results

Multiple SNPs in the FGFR2 locus were significantly associated with contralateral breast cancer, including rs1219648 (per allele rate ratio (RR) = 1.25, 95%CI = 1.08-1.45). Statistically significant associations with contralateral breast cancer were also observed at rs7313833, near the PTHLH gene (per allele RR = 1.26, 95%CI = 1.08-1.47), rs13387042 (2q35) (per allele RR = 1.19, 95%CI = 1.02-1.37), rs13281615 (8q24) (per allele RR = 1.21, 95%CI = 1.04-1.40), and rs11235127 near TMEM135 (per allele RR = 1.26, 95%CI = 1.04-1.53). The A allele of rs13387042 (2q35) was significantly associated with contralateral breast cancer in ER negative first tumors while the A allele of rs11235127 (near TMEM135) was significantly associated with contralateral breast cancer in ER positive first tumors. Although some SNP genotypes appeared to modify contralateral breast cancer risk with respect to tamoxifen treatment or particular radiation doses, trend tests for such effects were not significant.

Conclusions

Our results indicate that some common risk variants associated with primary breast cancer also increase risk for contralateral breast cancer, and that these risks vary with the ER status of the first tumor.     

Genome-wide single nucleotide polymorphism analysis of lung cancer risk detects the KLF6 gene

A genome-wide association analysis using the Affymetrix 100K SNP array was carried out in a case-control study of lung cancer. Allele frequencies were estimated initially in DNA pools. Significant differences in allele frequency detected in the SNP array analysis were first tested in the same DNA pools by pyrosequencing and then by individual genotyping. DNA pooling analysis identified rs10508266 SNP, located approximately 12.5kb from the 5'-end of the KLF6 gene, as a marker showing significant association with lung cancer risk. Since the SNP was in significant linkage disequilibrium with the KLF6 gene region, we analyzed an Italian population of 338 lung adenocarcinoma cases and 335 controls for the possible role of the reported functional rs3750861 SNP, located 15.6kb from the rs10508266 SNP. The rs3750861 affects expression of KLF6 splicing variants in prostate cancer and we found that its rare allele is associated with reduced lung cancer risk (odds ratio, 0.5; 95% CI, 0.3-0.8). A Norwegian replication series of 265 non small cell lung cancer cases, and 356 controls, however, did not confirm the association. In light of the reported functional involvement of the KLF6 gene in lung cancer and in other cancer types and to the functional nature of the rs3750861 SNP, our results suggest a potential involvement of KLF6 polymorphisms in lung cancer risk, although additional studies in large series are needed to confirm our findings and to elucidate the mechanism by which the KLF6 SNPs influence lung cancer risk.     

Estrogen Receptor β lpar;ESR2) Polymorphisms and Endometrial Cancer (United States)

OBJECTIVE: We hypothesized that variations in the ESR2 gene may influence estrogen exposure in the uterus and thus influence endometrial cancer risk. We validated and screened for variants in the ESR2 gene and examined whether they are associated with endometrial cancer risk. METHODS: We resequenced the promoter and coding regions of the ESR2 gene in 24 endometrial cancer cases, and genotyped the validated/discovered SNPs and intronic dinucleotide CA repeat in a nested case-control study of endometrial cancer (cases = 222, controls = 666) in the Nurses' Health Study (NHS). We also explored statistical interaction between ESR2 genotypes and body mass index (BMI) or hormone replacement therapy (HRT) use among postmenopausal women and cancer risk. RESULTS: Two SNPs were validated [rs1256049 in exon 5 (allelic frequencies = 98% G, 2% A) and rs1271572 in the promoter region (allelic frequencies = 60% G, 40% T)]. After adjusting for potential confounders, we observed no association between ESR2 gene polymorphisms and endometrial cancer risk [rs1256049 (OR = 1.2; 95%CI: 0.7-2.3), rs1271572 (OR = 0.8; 95%CI: 0.5-1.1) and CA repeat (22 repeat allele versus > or = 22 repeat allele, OR = 1.1; 95%CI: 0.7-1.7)]. We also did not observe any significant effect modification of the ESR2 polymorphisms by BMI or HRT use among postmenopausal women. CONCLUSION: Our results indicate that ESR2 polymorphisms may not be associated with endometrial cancer risk.     

Association between single nucleotide polymorphisms on chromosome 17q and the risk of prostate cancer in a Chinese population

In European populations, 7 single nucleotide polymorphisms (SNPs) on chromosome 17q, 3 SNPs on 17q12, and 4 SNPs on 17q24.3 were recently identified to be closely related to the risk of prostate cancer by a genome-wide association study. In Japanese populations, the correlation between 2 SNPs on 17q and the risk of prostate cancer and tumor aggressiveness was also confirmed by a large-scale experiment. However, whether 17q is associated with prostate cancer and its clinical manifestations in Chinese populations is still unknown. Therefore, we conducted a case-control study in a northern Chinese population and tested 2 SNPs, rs4430796 and rs1859962, on 17q in 124 prostate cancer patients and 111 controls using polymerase chain reaction-high resolution melting curve (PCR-HRM) combined with sequencing. We analyzed the association of the 2 SNPs with the risk of prostate cancer as well as patients' lifestyles, onset ages, Gleason scores, PSA levels, and pathologic stages. We found a significant difference in the G allele of SNP rs1859962 (P = 0.035, OR = 1.51, 95% CI = 1.03-2.21) but not in the rs4430796 genotype frequency or allele frequency distribution between prostate cancer patients and the controls (P > 0.05). Neither of the SNPs was significantly associated with the onset age, Gleason score, PSA level, pathologic stage, or other clinical indicators of patients with prostate cancer (P > 0.05). Our results show that polymorphism of the G allele of SNP rs1859962 is associated with the risk of prostate cancer in a Chinese population.     

A genome-wide association study identifies a locus on chromosome 14q21 as a predictor of leukocyte telomere length and as a marker of susceptibility for bladder cancer

Telomeres play a critical role in maintaining genome integrity. Telomere shortening is associated with the risk of many aging-related diseases. Classic twin studies have shown that genetic components may contribute up to 80% of the heritability of telomere length. In the study we report here that we used a multistage genome-wide association study to identify genetic determinants of telomere length. The mean telomere length in peripheral blood leukocytes was measured by quantitative real-time PCR. We first analyzed 300,000 single-nucleotide polymorphisms (SNPs) in 459 healthy controls, finding 15,120 SNPs associated with telomere length at P < 0.05. We then validated these SNPs in two independent populations comprising 890 and 270 healthy controls, respectively. Four SNPs, including rs398652 on 14q21, were associated with telomere length across all three populations (pooled P values of <10(-5)). The variant alleles of these SNPs were associated with longer telomere length. We then analyzed the association of these SNPs with the risk of bladder cancer in a large case-control study. The variant allele of rs398652 was associated with a significantly reduced risk of bladder cancer (odds ratio = 0.81; 95% confidence interval, 0.67-0.97; P = 0.025), consistent with the correlation of this variant allele with longer telomeres. We then conducted a mediation analysis to examine whether the association between rs398652 and reduced bladder cancer risk is mediated by telomere length, finding that telomere length was a significant mediator of the relationship between rs398652 and bladder cancer (P = 0.013), explaining 14% of the effect. In conclusion, we found that the SNP rs398652 on 14q21 was associated with longer telomere length and a reduced risk of bladder cancer and that a portion of the effect of this SNP on bladder cancer risk was mediated by telomere length.     

Polymorphic variants in PTGS2 and prostate cancer risk: results from two large nested case-control studies

Chronic inflammation has been hypothesized to increase prostate cancer risk. Prostaglandin-endoperoxide synthase 2 (PTGS2) encodes the proinflammatory cyclooxygenase 2 enzyme believed to be the rate-limiting step in the synthesis of prostaglandins, important mediators of inflammation. We investigated associations between PTGS2 polymorphisms and prostate cancer risk among 2321 prostate cancer cases and 2560 controls in two large case-control studies nested within the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial and the Cancer Prevention Study II Nutrition Cohort. Five single nucleotide polymorphisms (SNPs) (rs5277, rs20432, rs4648276, rs5275 and rs689470) were examined in SNP and haplotype analyses (five SNPs in PLCO and four SNPs in the Nutrition Cohort). In PLCO, the Ex10 +837 T>C marker (rs5275) was initially associated with prostate cancer risk (P-trend = 0.02) but became non-significant after adjustment for multiple comparisons (P = 0.08); this SNP showed no association with prostate cancer risk in the Nutrition Cohort (P-trend = 0.54) or in an analysis pooling the two cohorts (P-trend = 0.20). No other SNP was associated with prostate cancer risk in PLCO or the Nutrition Cohort individually or combined. Haplotype analyses suggested an association between PTGS2 variants in PLCO alone (global P = 0.007), but not in the Nutrition Cohort (global P = 0.78) or pooled analysis (global P = 0.18). In conclusion, despite the potential importance of inflammation in prostate carcinogenesis, results from our large study of five PTGS2 SNPs does not support a strong association between PTGS2 variants and prostate cancer risk in non-Hispanic white men.     

Genetic polymorphisms in obesity-related genes and endometrial cancer risk

BACKGROUND:

Obesity is associated with circulating levels of adiponectin and leptin and endometrial cancer risk. Little is known about whether single nucleotide polymorphisms (SNPs) in the genes that encode adiponectin (ADIPOQ), leptin (LEP), adiponectin receptor 1 (ADIPOR1), adiponectin receptor 2 (ADIPOR2), and leptin receptor (LEPR) are associated with endometrial cancer.

METHODS:

The authors selected 87 tagging SNPs to capture common genetic variants in these 5 genes. These SNPs were evaluated in 1028 endometrial cancer cases and 1932 community controls recruited from Chinese women. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs).

RESULTS:

Three of the 10 SNPs evaluated in the ADIPOQ gene were significantly associated with reduced cancer risk. The OR for women homozygous for the minor allele (A/A) for rs3774262 was 0.68 (95% CI, 0.48‐0.97) compared with women homozygous for the major allele (G/G). Similar results were found for SNPs rs1063539 and rs12629945 in ADIPOQ, which were in linkage disequilibrium with rs3774262. These associations became nonsignificant after Bonferroni correction was applied. Controls with the minor allele A at rs3774262 had lower weight, smaller waist and hip circumferences, and lower body mass index than controls with the major allele G (all P < .05). Women homozygous for the minor allele (T/T) of rs2071045 in the LEP gene also had significantly lower risk (OR, 0.70; 95% CI, 0.54‐0.90) than women homozygous for the major allele (C/C). No other SNPs in the LEP, ADIPOR1, ADIPOR2, or LEPR genes were found to be associated with cancer risk.

CONCLUSIONS:

Although a chance finding cannot be ruled out, the consistency of findings for gene‐endometrial cancer risk and gene‐obesity measurements suggests that genetic polymorphisms in the ADIPOQ gene may play a role in endometrial cancer development. Cancer 2011. © 2011 American Cancer Society.     

Genetic variation in genes encoding for polymerase ζ subunits associates with breast cancer risk, tumour characteristics and survival

Chromosomal instability is a known hallmark of many cancers. DNA polymerases represent a group of enzymes that are involved in the mechanism of chromosomal instability as they have a central function in DNA metabolism. We hypothesized that genetic variation in the polymerase genes may affect gene expression or protein configuration and by that cancer risk and clinical outcome. We selected four genes encoding for the catalytic subunits of the polymerases β, δ, θ and ζ (POLB, POLD1, POLQ and REV3L, respectively) and two associated proteins (MAD2L2 and REV1) because of their previously reported association with chromosomal instability and/or tumorigenesis. We selected potentially functional and most informative tagging single nucleotide polymorphisms (SNPs) for genotyping in a population-based series of 783 Swedish breast cancer (BC) cases and 1562 controls. SNPs that showed a significant association in the Swedish population were additionally genotyped in a Polish population consisting of 506 familial/early onset BC cases and 568 controls. SNPs in all three polymerase ζ subunit genes associated either with BC risk or prognosis. Two SNPs in REV3L and one SNP in MAD2L2 associated with BC risk: rs462779 (multiplicative model: OR 0.79, 95% CI 0.68-0.92), rs3204953 (dominant model: OR 1.28, 95% CI 1.05-1.56) and rs2233004 (recessive model: OR 0.49, 95% CI 0.28-0.86). Homozygous carriers of the minor allele C of the third SNP in REV3L, rs11153292, had significantly worse survival compared to the TT genotype carriers (HR 2.93, 95% CI 1.34-6.44). Minor allele carriers of two REV1 SNPs (rs6761391 and rs3792142) had significantly more often large tumours and tumours with high histological grade and stage. No association was observed for SNPs in POLB, POLQ and POLD1. Altogether, our data suggest a significant role of genetic variation in the polymerase ζ subunit genes regarding the development and progression of BC.