雌激素受體α基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性的meta分析*

馬英東， 王阿妮， 鐘韶萍， 金莉子

(中山大學(xué)附屬第五醫(yī)院 1介入科， 2冠心病重癥監(jiān)護(hù)室， 3心內(nèi)科， 廣東 珠海 519000)

?

雌激素受體α基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性的meta分析*

馬英東1， 王阿妮3， 鐘韶萍1， 金莉子2△

(中山大學(xué)附屬第五醫(yī)院1介入科，2冠心病重癥監(jiān)護(hù)室，3心內(nèi)科， 廣東 珠海 519000)

目的： 探討雌激素受體α(ESRα)基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性的關(guān)系。方法: 通過計(jì)算機(jī)檢索PubMed、CNKI和萬方數(shù)據(jù)庫，根據(jù)納入與排除標(biāo)準(zhǔn)篩選相關(guān)的病例對(duì)照研究，檢索時(shí)限至2014年4月。在提取有效資料后，應(yīng)用Stata 10.1 分析軟件對(duì)各項(xiàng)研究進(jìn)行異質(zhì)性檢驗(yàn)，在隨機(jī)效應(yīng)模型下計(jì)算合并優(yōu)勢比及其95%可信區(qū)間。結(jié)果: 該Meta分析共納入20項(xiàng)研究，累計(jì)前列腺癌組4 623例，對(duì)照組9 850例。ESRαrs2234693位點(diǎn)多態(tài)性在總體人群中與前列腺癌易感性明顯相關(guān)(P<0.05)，通過種族的亞組分析發(fā)現(xiàn)ESRαrs2234693位點(diǎn)多態(tài)性與前列腺癌易感性在歐洲人群中具有相關(guān)性(P<0.05)，然而在亞洲和非洲人群中無明顯關(guān)聯(lián)性(均P>0.05)。結(jié)論:ESRα基因 rs2234693位點(diǎn)態(tài)性與前列腺癌易感性相關(guān)，即rs2234693 的CC基因型可增加人群患前列腺癌的風(fēng)險(xiǎn)，尤其是歐洲人群。

雌激素受體α； 基因多態(tài)性； 前列腺腫瘤； Meta分析

前列腺癌是男性最常見的惡性腫瘤之一，占男性癌癥死亡病因的10%[1]，然而人們對(duì)于前列腺癌的發(fā)病原因仍不清楚。許多研究者認(rèn)為有可能是環(huán)境因素和(或)遺傳因素作用導(dǎo)致的。近年來的研究發(fā)現(xiàn), 一些特殊基因的多態(tài)性與前列腺癌的發(fā)生之間存在著復(fù)雜的相關(guān)性[2-6]。人類雌激素受體α(estrogen receptor α，ESRα)基因定位在染色體6號(hào)染色體長臂25區(qū)1帶(6q25.1)[7]，其內(nèi)含子和外顯子區(qū)域的若干多態(tài)性位點(diǎn)已被確定。其中，位于第1個(gè)內(nèi)含子內(nèi)的rs2234693位點(diǎn)是被廣泛研究的基因多態(tài)性位點(diǎn)之一。雖然目前有許多關(guān)于ESRα基因rs2234693位點(diǎn)的多態(tài)性與前列腺癌易感性的研究[8-23]，但由于這些同類研究質(zhì)量參差不齊，樣本量較小，使其結(jié)果存在分歧或不確定性。本研究旨在通過Cochrane 系統(tǒng)評(píng)價(jià)方法，對(duì)所有公開發(fā)表的ESRα基因rs2234693位點(diǎn)的多態(tài)性與前列腺癌易感性相關(guān)的病例對(duì)照研究進(jìn)行meta 分析，為基礎(chǔ)研究和臨床治療提供更可靠的證據(jù)。

材 料 和 方 法

1 納入及排除標(biāo)準(zhǔn)

納入標(biāo)準(zhǔn)為：(1)文獻(xiàn)類型為病例對(duì)照研究；(2)病例組為組織學(xué)檢查確診為前列腺癌患者，對(duì)照組為與患者無血緣關(guān)系的非前列腺癌健康人群；(3)對(duì)照組基因型分布符合Hardy-Weinberg 遺傳平衡定律；(4)文獻(xiàn)中提供基因型數(shù)據(jù)。剔除標(biāo)準(zhǔn)為：(1)研究中只有病例組沒有對(duì)照組；(2)同一研究重復(fù)發(fā)表文獻(xiàn)；(3)數(shù)據(jù)不完整。

2 文獻(xiàn)檢索

以“single nucleotide polymorphism or SNP or variants”、 “prostate cancer or carcinoma”和“estrogen receptor alpha或ESR1”為英文關(guān)鍵詞，檢索PubMed數(shù)據(jù)庫；同時(shí)以“基因多態(tài)性”、“前列腺癌”和“雌激素受體α基因”為中文關(guān)鍵詞檢索CNKI和萬方數(shù)據(jù)庫。檢索時(shí)限均為建庫至2014年4月。

3 質(zhì)量評(píng)價(jià)及數(shù)據(jù)提取

由2名研究者獨(dú)立閱讀檢索文獻(xiàn)摘要，對(duì)可能符合納入標(biāo)準(zhǔn)的文獻(xiàn)進(jìn)一步閱讀全文，如有分歧通過討論解決或由第3位研究者決定是否納入。對(duì)納入的文獻(xiàn)參考Cochrane Reviewer’s Handbook 5.0系統(tǒng)評(píng)價(jià)員手冊推薦的質(zhì)量評(píng)價(jià)標(biāo)準(zhǔn)進(jìn)行以下質(zhì)量評(píng)價(jià): (1) 診斷標(biāo)準(zhǔn)是否明確; (2) 樣本量是否充分; (3) 病例組和對(duì)照組是否具有可比性; (4) 統(tǒng)計(jì)學(xué)分析方法是否恰當(dāng); (5) 是否對(duì)本研究可能存在的偏倚進(jìn)行了討論。以上每項(xiàng)為 1分，≥3分為質(zhì)量可靠。從每個(gè)納入的文獻(xiàn)中提取主要數(shù)據(jù)為：第一作者、發(fā)表年份、樣本量、種族、病例組和對(duì)照組基因型頻率、Hardy-Weinberg遺傳平衡定律。

4 統(tǒng)計(jì)學(xué)處理

采用Stata 10.1 軟件進(jìn)行meta分析。首先通過Q檢驗(yàn)和I2檢驗(yàn)對(duì)各研究的結(jié)果進(jìn)行異質(zhì)性檢驗(yàn)[24]，若Q檢驗(yàn)的P值大于0.1或I2值小于50%，則說明各研究間無顯著統(tǒng)計(jì)學(xué)異質(zhì)性，采用固定效應(yīng)模型進(jìn)行合并分析；若Q檢驗(yàn)的P值小于0.1或I2值大于50%，則說明結(jié)果間存在顯著統(tǒng)計(jì)學(xué)異質(zhì)性，且未發(fā)現(xiàn)來源于臨床異質(zhì)性，則可采用隨機(jī)效應(yīng)模型法進(jìn)行數(shù)據(jù)合并[25]。然后計(jì)算合并優(yōu)勢比(odds ratio,OR)及95% 可信區(qū)間(confidence interval,CI)，以P<0.05為差異有統(tǒng)計(jì)學(xué)意義，通過Egger’s和Begg’s檢驗(yàn)評(píng)價(jià)發(fā)表性偏倚[26-27]，最后繪制OR值分布森林圖和漏斗圖。

結(jié) 果

1 納入文獻(xiàn)的基本特征

文獻(xiàn)篩選流程見圖1。初檢獲得相關(guān)文獻(xiàn)75篇，閱讀標(biāo)題、摘要和全文，根據(jù)文獻(xiàn)納入和剔除標(biāo)準(zhǔn)，最終納入符合要求的文獻(xiàn)16篇[8-23]，其中共涉及20項(xiàng)獨(dú)立研究，試驗(yàn)設(shè)計(jì)均為病例對(duì)照，而且各項(xiàng)研究對(duì)照組的基因型分布均符合Hardy-Weinberg 遺傳平衡定律。所有研究的基本特征見表1。納入的20項(xiàng)研究累計(jì)前列腺癌患者4 623例，正常對(duì)照者9 850例。

Figure 1.The flow chart of literature search and study selection.

2 Meta分析結(jié)果

以野生純合子TT基因型為參照，評(píng)估突變純合子CC基因型與前列腺癌易感性的關(guān)系。因異質(zhì)性檢驗(yàn)結(jié)果顯示各研究間存在統(tǒng)計(jì)學(xué)異質(zhì)性(I2=52.7%，P=0.003)，故采用隨機(jī)效應(yīng)模型進(jìn)行meta 分析并繪制森林圖，見圖2。結(jié)果顯示，在ESRαrs2234693位點(diǎn)攜帶CC 基因型的人群前列腺癌的發(fā)病危險(xiǎn)比攜帶TT 基因型的人群高(OR=1.29, 95% CI: 1.08～1.55,P=0.005)。進(jìn)一步以種族因素做亞組分析，結(jié)果顯示，ESRα基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性在歐洲人群中具有相關(guān)性(OR=1.26, 95% CI: 1.01～1.58,P=0.041)，然而在亞洲和非洲人群中無明顯關(guān)聯(lián)性(亞洲人OR=1.37, 95% CI: 0.94～1.99,P=0.099; 非洲人OR=1.52, 95% CI: 0.86～2.69,P=0.145)。

3 發(fā)表性偏倚評(píng)價(jià)

漏斗圖中(圖3)納入的20項(xiàng)研究以合并效應(yīng)量OR 值(中線)為中心散開分布，基本對(duì)稱，呈倒置漏斗形，提示無明顯發(fā)表性偏倚。進(jìn)一步Egger’s和Begg’s檢驗(yàn)也提示總體研究不存在明顯的發(fā)表性偏倚(Egger’s:P=0.169; Begg’s:P=0.132)。

表1 所納入的 20 項(xiàng)病例對(duì)照研究的基本特征

HWE: Hardy-Weinberg equilibrium, for control.

Figure 2.Forest plot of the association between ESRα rs2234693 and prostate cancer risk (CC vs TT).

Figure 3.Funnel plot analysis to detect publication bias

討 論

ESR 屬于一類由配體激活的核轉(zhuǎn)錄因子，現(xiàn)發(fā)現(xiàn)的人類ESR 主要存在2種亞型：ESRα和ESRβ，其中ESRα主要分布于前列腺基底上皮細(xì)胞和基質(zhì)間隙[28]，而編碼ESRα的基因則定位于人類染色體6q25.1上，全序列共有14萬個(gè)堿基對(duì)，由8 個(gè)外顯子和7 個(gè)內(nèi)含子組成。rs2234693是ESRα基因最常見的多態(tài)性位點(diǎn)，位于第1個(gè) 內(nèi)含子內(nèi)距第2個(gè)外顯子上游397 bp位置。由于第1個(gè)內(nèi)含子位于氨基末端主要轉(zhuǎn)錄功能區(qū)，其含有啟動(dòng)子和增強(qiáng)子等重要調(diào)節(jié)序列，rs2234693在其中發(fā)生的堿基T 和C 置換有可能產(chǎn)生導(dǎo)致原有的酶切位點(diǎn)消失或產(chǎn)生新的酶切位點(diǎn)，無論是哪一種形式，都可以導(dǎo)致mRNA的錯(cuò)誤剪接，最后產(chǎn)生異常的表達(dá)產(chǎn)物[29-30]，而雌激素必須與ESRα結(jié)合才能發(fā)揮作用，異常ESRα的表達(dá)將直接影響個(gè)體內(nèi)雌激素的最終生理效應(yīng)，進(jìn)而對(duì)前列腺癌的發(fā)生、發(fā)展產(chǎn)生影響。因此我們有理由推測，ESRα rs2234693位點(diǎn)基因多態(tài)性可能是前列腺癌發(fā)病的危險(xiǎn)因素。

到目前為止，已有2篇針對(duì)ESRα基因 rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性的meta分析論文發(fā)表[31-32]，但由于發(fā)表時(shí)間和篩選資料的標(biāo)準(zhǔn)不同，它們所納入的文獻(xiàn)不相一致，導(dǎo)致得出的結(jié)論并不穩(wěn)定。本研究通過全面檢索中英文數(shù)據(jù)庫，根據(jù)嚴(yán)格的納入及排除標(biāo)準(zhǔn)共納入20項(xiàng)關(guān)于ESRα基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性的研究，并采用meta 分析的方法對(duì)其結(jié)果進(jìn)行定量合并，是目前收集病例組及對(duì)照組數(shù)量最多的meta分析。研究結(jié)果顯示ESRα基因rs2234693位點(diǎn)多態(tài)性與前列腺癌易感性相關(guān)，即rs2234693 的CC基因型可增加人群患前列腺癌的風(fēng)險(xiǎn)，尤其是歐洲人群；對(duì)于亞洲人群而言，rs2234693 的CC基因型與前列腺癌易感性之間無明顯相關(guān)性，但由于納入的文獻(xiàn)僅5篇，樣本量較局限，因此尚不能下最后結(jié)論。同時(shí)，需要指出的本研究存在的局限性是：(1)由于語言的限制，本研究所選擇的數(shù)據(jù)庫僅限于英文和中文，對(duì)其它語言或數(shù)據(jù)庫的文獻(xiàn)沒有進(jìn)行搜選；(2)本研究只針對(duì)ESRα基因的rs2234693位點(diǎn)進(jìn)行分析，未考慮基因與基因和基因與環(huán)境等相互作用的影響。因此上述結(jié)果仍需在進(jìn)一步的嚴(yán)格設(shè)計(jì)、最大程度控制混雜因素、大樣本、同質(zhì)性的病例對(duì)照或前瞻性研究中加以驗(yàn)證，同時(shí)也需要充分考慮基因之間以及基因與環(huán)境之間的相互作用，以便發(fā)現(xiàn)前列腺癌的發(fā)病機(jī)制，為基礎(chǔ)研究和臨床治療提供更可靠的證據(jù)。

[1] Jemal A, Bray F, Center MM, et al. Global cancer statistics[J]. CA Cancer J Clin, 2011, 61(2):69-90.

[2] Vesovic Z, Herkommer K, Vogel W, et al. Role of a CYP17 promoter polymorphism for familial prostate cancer risk in Germany[J]. Anticancer Res, 2005, 25(2B):303-307．

[3] Brankovic A, Brajuskovic G, Nikolic Z, et al. Endothelial nitric oxide synthase gene polymorphisms and prostate cancer risk in Serbian population[J]. Int J Exp Pathol, 2013, 94(6):355-361.

[4] Zabaleta J, Lin HY, Sierra RA, et al. Interactions of cytokine gene polymorphisms in prostate cancer risk[J]. Carcinogenesis, 2008, 29(3):573-578.

[5] 孫穎浩, 楊 波, 王小慧, 等. 雌激素受體β的單核苷酸多態(tài)性與前列腺癌風(fēng)險(xiǎn)的相關(guān)性研究[J]. 中華外科雜志, 2005, 43(14):948-951.

[6] 李 峰, 李 帥, 郭麗榮, 等. 雌激素受體2對(duì)前列腺癌細(xì)胞系PC-3M增殖的影響[J]. 中國病理生理雜志, 2009, 25(4):656-660.

[7] Herynk MH, Fuqua SA. Estrogen receptor mutations in human disease[J]. Endocr Rev, 2004, 25(6):869-898.

[8] Modugno F, Weissfeld JL, Trump DL, et al. Allelic variants of aromatase and the androgen and estrogen receptors: toward a multigenic model of prostate cancer risk[J]. Clin Cancer Res, 2001, 7(10):3092-3096.

[9] Tanaka Y, Sasaki M, Kaneuchi M, et al. Polymorphisms of estrogen receptor alpha in prostate cancer[J]. Mol Carcinog, 2003, 37(4):202-208.

[10]Fukatsu T, Hirokawa Y, Araki T, et al. Genetic polymorphisms of hormone-related genes and prostate cancer risk in the Japanese population[J]. Anticancer Res, 2004, 24(4):2431-2437.

[11]Hernandez J, Balic I, Johnson-Pais TL, et al. Association between an estrogen receptor alpha gene polymorphism and the risk of prostate cancer in black men[J]. J Urol, 2006, 175(2):523-527.

[12]Low YL, Taylor JI, Grace PB, et al. Phytoestrogen exposure, polymorphisms in COMT, CYP19, ESR1, and SHBG genes, and their associations with prostate cancer risk[J]. Nutr Cancer, 2006, 56(1):31-39.

[13]Kjaergaard AD, Ellervik C, Tybjaerg-Hansen A, et al. Estrogen receptor alpha polymorphism and risk of cardiovascular disease, cancer, and hip fracture: cross-sectio-nal, cohort, and case-control studies and a meta-analysis[J]. Circulation, 2007, 115(7):861-871.

[14]Cunningham JM, Hebbring SJ, McDonnell SK, et al. Evaluation of genetic variations in the androgen and estrogen metabolic pathways as risk factors for sporadic and familial prostate cancer[J]. Cancer Epidemiol Biomarkers Prev, 2007, 16(5):969-978.

[15]Berndt SI, Chatterjee N, Huang WY, et al. Variant in sex hormone-binding globulin gene and the risk of prostate cancer[J]. Cancer Epidemiol Biomarkers Prev, 2007, 16(1):165-168.

[16]Onsory K, Sobti RC, Al-Badran AI, et al. Hormone receptor-related gene polymorphisms and prostate cancer risk in North Indian population[J]. Mol Cell Biochem, 2008, 314(1-2):25-35.

[17]Beuten J, Gelfond JA, Franke JL, et al. Single and multigenic analysis of the association between variants in 12 steroid hormone metabolism genes and risk of prostate cancer[J]. Cancer Epidemiol Biomarkers Prev, 2009, 18(6):1869-1880.

[18]Gupta L, Thakur H, Sobti RC, et al. Role of genetic po-lymorphism of estrogen receptor-alpha gene and risk of prostate cancer in north Indian population[J]. Mol Cell Biochem, 2010, 335(1-2):255-261.

[19]Sonoda T, Suzuki H, Mori M, et al. Polymorphisms in estrogen related genes may modify the protective effect of isoflavones against prostate cancer risk in Japanese men[J]. Eur J Cancer Prev, 2010, 19(2):131-137.

[20]Sissung TM, Danesi R, Kirkland CT, et al. Estrogen receptor α and aromatase polymorphisms affect risk, prognosis, and therapeutic outcome in men with castration-resistant prostate cancer treated with docetaxel-based therapy[J]. J Clin Endocrinol Metab, 2011, 96(2):E368-E372.

[21]Szendroi A, Speer G, Tabak A, et al. The role of vitamin D, estrogen, calcium sensing receptor genotypes and serum calcium in the pathogenesis of prostate cancer[J]. Can J Urol, 2011, 18(3):5710-5716.

[22]Safarinejad MR, Safarinejad S, Shafiei N, et al. Estrogen receptors alpha (rs2234693 and rs9340799), and beta (rs4986938 and rs1256049) genes polymorphism in prostate cancer: evidence for association with risk and histopathological tumor characteristics in Iranian men[J]. Mol Carcinog, 2012, 51 (Suppl 1):E104-E117.

[23]Jurecekova J, Sivonova MK, Evinova A, et al. The association between estrogen receptor alpha polymorphisms and the risk of prostate cancer in Slovak population[J]. Mol Cell Biochem, 2013, 381(1-2):201-207.

[24]Wang T, Wang B. Association between glutathioneS-transferase M1/glutathioneS-transferase T1 polymorphisms and Parkinson’s disease: a meta-analysis[J]. J Neurol Sci, 2014, 338(1-2):65-70.

[25]DerSimonian R, Laird N. Meta-analysis in clinical trials[J]. Control Clin Trials, 1986, 7(3):177-188.

[26]Egger M, Davey SG, Schneider M, et al. Bias in meta-analysis detected by a simple, graphical test[J]. BMJ, 1997, 315(7109):629-634.

[27]Begg CB, Mazumdar M. Operating characteristics of a rank correlation test for publication bias[J]. Biometrics, 1994, 50(4):1088-1101.

[28]Hiramatsu M, Maehara I, Orikasa S, et al. Immunoloca-lization of oestrogen and progesterone receptors in prostatic hyperplasia and carcinoma[J]. Histopathology, 1996, 28(2):163-168.

[29]Matsubara Y, Murata M, Kawano K, et al. Genotype distribution of estrogen receptor polymorphisms in men and postmenopausal women from healthy and coronary populations and its relation to serum lipid levels[J]. Arterioscler Thromb Vasc Biol, 1997, 17(11):3006-3012.

[30]季敬璋, 白永恒, 俞雅萍, 等. 雌激素受體α基因多態(tài)性與良性前列腺增生相關(guān)研究[J]. 溫州醫(yī)學(xué)院學(xué)報(bào), 2010, 40(1):9-12.

[31]Ding X, Cui FM, Xu ST, et al. Variants on ESR1 and their association with prostate cancer risk: a meta-analysis[J]. Asian Pac J Cancer Prev, 2012, 13(8):3931-3936.

[32]Gu Z, Wang G, Chen W. Estrogen receptor alpha gene polymorphisms and risk of prostate cancer: a meta-analysis involving 18 studies[J]. Tumor Biol, 2014, 35(6):5921-5930.

A meta-analysis ofESRαrs2234693 polymorphism associated with prostate cancer risk

MA Ying-dong1, WANG A-ni3, ZHONG Shao-ping1, JIN Li-zi2

(1InvasiveTechnologyDepartment,2CoronaryHeartDiseaseIntensiveCareUnit,3CardiologyDepartment,TheFifthAffiliatedHospitalofSunYat-senUniversity,Zhuhai519000,China.E-mail:Jinlizizhuhai@163.com)

AIM: To investigate the pooled association between estrogen receptor α (ESRα) rs2234693 polymorphism and prostate cancer risk. METHODS: A systematic literature search was performed to identify the related studies (up to April 2014) in several online databases including PubMed, the CNKI and Wanfang online libraries. Odds ratios with 95% confidence intervals were used to calculate the strength of association in the random effect model. RESULTS: A total of 20 studies including 4 623 cases and 9 850 controls were enrolled in the final meta-analysis. The results indicated thatESRαrs2234693 polymorphism was significantly associated with prostate cancer risk (P<0.05) in a dominant genetic model. In the subgroup analysis by ethnicity, there were significant associations betweenESRαrs2234693 polymorphism and prostate cancer risk in Caucasians (P<0.05), but not in Asians and Africans (bothP>0.05). CONCLUSION: This meta-analysis suggests thatESRαrs2234693 polymorphism is significantly associated with prostate cancer risk, especially in Caucasians.

Estrogen receptor α; Genetic polymorphism; Prostatic neoplasms; Meta-analysis

1000- 4718(2015)01- 0104- 05

2014- 07- 21

2014- 11- 13

珠海市科技計(jì)劃項(xiàng)目(No. 2012D0401990002)

△通訊作者 Tel: 0756-2528200； E-mail: Jinlizizhuhai@163.com

R195.1;R4

A

10.3969/j.issn.1000- 4718.2015.01.020