螺旋断层放疗在胸中下段食管癌治疗中对心脏功能保护的研究

【摘要】目的:对比胸中下段食管癌螺旋断层放疗和适形调强放疗心脏的剂量分布,分析螺旋断层放疗前后的心肌酶谱,评估螺旋断层放疗在食管癌治疗中对心脏功能的保护作用。方法:筛选37例胸中下段食管鳞癌患者,为每位患者制定适形调强放疗和螺旋断层放疗计划,比较两种放疗方式的计划靶区（PTV）、心脏的剂量学参数。同时在螺旋断层放疗前一周及一周后进行心肌酶谱检查,并对放疗心肌酶谱进行对比分析。结果:螺旋断层放疗的PTV与心脏最大剂量,心脏V20、V30、V40、V50、V60均明显低于适形调强放疗,差异有统计学意义（P<0.05）;两种放疗方式的PTV适形度指数差异有统计学意义（P<0.05）,而PTV均匀性指数、TOMO前后心肌酶谱差异无统计学意义（P>0.05）。结论:螺旋断层放疗在靶区剂量分布优于适形调强放疗的条件下,能显著降低心脏的最大剂量,并且引起的早期心肌损伤不明显,对心脏起到更好的保护作用。     

妊娠期高血压疾病胎盘组织中CASR和EGFR的相关研究

目的探讨在妊娠期高血压疾病患者胎盘组织中细胞外钙受体（CASR）和表皮生长因子受体（EGFR）的表达情况及其相互关系。方法通过免疫组织化学方法检测妊娠期高血压疾病患者64例（妊娠期高血压组21例,子痫前期轻度组23例,重度组20例）及健康足月孕妇20例（对照组）胎盘组织中CASR和EGFR蛋白的表达情况。结果 （1）妊娠期高血压疾病患者胎盘组织中CASR在妊娠期高血压组表达水平为59.0532±8.039,子痫前期轻度组患者中为64.3623±3.7278,两组比较,差异有统计学意义（P〈0.0001）;CASR在子痫前期重度组患者中表达为112.2831±6.2060,与妊娠期高血压组比较,差异有统计学意义（P〈0.0001）,与子痫前期轻度组比较,差异有统计学意义（P〈0.0001）。CASR的蛋白在妊娠期高血压组患者胎盘组织中表达水平为59.0532±8.039,对照组为54.8585±4.3035,两组比较,差异无显著性（t=0.08,P=0.7759）。（2）妊娠期高血压疾病患者胎盘组织中表皮生长因子受体（EGFR）在妊娠期高血压组表达水平为56.174±3.1020,子痫前期轻度组患者中为78.6844±2.6713,两组比较,差异有统计学意义（t=18.73,P=0.0001）;EGFR在子痫前期重度组患者中表达为94.2090±6.8352,与子痫前期轻度组比较,差异有统计学意义（t=11.37,P〈0.0001）。（3）胎盘组织中CASR和表皮生长因子受体（EGFR）表达量呈正相关关系（r=0.352,P〈0.05）。结论妊娠期高血压疾病患者胎盘组织中CASR的蛋白表达升高和EGFR激活及过度增高,可能在妊娠期高血压疾病发生发展中起重要作用。     

胃癌癌变相关基因表达的cDNA微阵列研究

目的 建立胃癌基因表达谱,筛选胃癌相关基因。方法 用含10000个已知基因和7000个ESTs(expressed sequence tags)的cDNA微阵列分析胃癌和癌旁正常胃黏膜基因表达谱的变化,半定量RT-PCR研究差异表达基因与胃癌的关系。结果 二倍以上的差异表达基因359个,其中在胃癌组织中表达上调271个,表达下调88个;二倍以上的差异表达ESTs 28个,其中在胃癌组织中表达上调24个,下调4个。RT-PCR进一步证实碳酸酐酶Ⅱ在胃癌组织中存在表达下调,胰岛素样生长因子结合蛋白4在胃癌组织中存在表达上调。结论 发现碳酸酐酶Ⅱ、胰岛素样生长因子结合蛋白4可能与胃癌发生有关,为进一步寻找和克隆胃癌相关基因提供了重要的研究线索。     

深Ⅱ度烫伤创面早期应用重组人表皮生长因子后表皮生长因子受体的表达

背景：有研究表明重组人表皮生长因子能促进烧伤创面愈合,内源性表皮生长因子通过与表皮生长因子受体结合发挥生物学效应。 目的：观察局部应用重组人表皮生长因子对大鼠烫伤创面表皮生长因子受体的影响,分析其促进创面愈合的可能机制。 方法：制备Wistar大鼠背部深Ⅱ度烫伤模型,分为2组,对照组于创面喷洒生理盐水,实验组喷洒重组人表皮生长因子。烫伤后0,1,3,5,7,10,14,21 d取创面组织,采用Western blot检测表皮生长因子受体蛋白表达,并测定两组大鼠创面愈合率。 结果与结论：烫伤后7-21 d 实验组创面愈合率高于对照组(P < 0.05)。两组表皮生长因子受体蛋白表达在1 d明显降低(P < 0.05),随后又升高,7 d达峰值且对照组比实验组高(P < 0.05);峰值过后,对照组逐渐下降,21 d接近烫伤前水平,实验组迅速下降,14 d达谷值,随后上升,21 d接近烫伤前水平,两组差异有显著性意义(P < 0.05)。说明早期局部应用重组人表皮生长因子可影响表皮生长因子受体的表达规律,并显著促进大鼠深Ⅱ度烫伤创面愈合。     

胃癌术后调强和三维适形计划的剂量学比较

目的：研究比较胃癌术后放疗中三维适形和调强两种不同方法产生的计划在靶区剂量分布,正常组织受量等方面的区别。比较两种计划的优缺点,以期指导临床应用。方法：选取5个胃癌术后放疗病人,勾画完靶区后,分别运用三维适形和调强制作计划,比较靶区适形度,均匀性,正常肝组织（Liver-PTV）的（V30,Mean）,双肾（V5,V15,V20,Mean）,脊髓的受量。结果：三维适形计划与调强计划相比,适形度,均匀性较差;正常肝组织的V30和平均剂量调强计划略优于三维适形;双肾的V15平均剂量两者没有明显差异,V20。调强略优于适形计划,小于V5,的低剂量体积调强计划要小于三维适形;脊髓受量两者没有明显差异。结论：总体来说,胃癌术后的调强计划靶区适形度,均匀性优于三维适形计划,正常组织受量与三维适形相当或者略优于三维适形。所以调强计划可以替代三维适形计划作为胃癌术后放疗的主要计划设计方法。     

表皮生长因子受体和P53与食管鳞状细胞癌放疗敏感性的关系

目的 分析食管鳞状细胞癌患者标本中表皮生长因子受体(EGFR)和P53表达水平与其临床病理特征的相关性,探讨术前放疗对EGFR和P53表达的影响,为临床食管鳞状细胞癌手术联合放疗的治疗策略提供理论依据.方法 采用免疫组织化学方法检测食管鳞状细胞癌患者标本中EGFR、P53蛋白的表达水平,分析其表达与食管鳞状细胞癌临床病理参数的关系,对比术前放疗对患者癌组织中EGFR和P53表达水平的影响.结果 与正常食管黏膜上皮组织相比,食管鳞状细胞癌组织中EGFR和P53的表达水平均显著升高;食管鳞状细胞癌组织中EGFR和P53的表达均与其组织学分级、浸润程度、有无区域淋巴结转移呈正相关;术前放射治疗可显著降低食管鳞状细胞癌组织中EGFR和P53的表达水平.结论 在食管鳞状细胞癌中,EGFR和P53的表达水平与其临床病理特征有密切关系,且呈正相关,检测两种蛋白的表达水平对食管鳞状细胞癌的恶性程度及预后判断具有重要的临床意义.     

TGFBR1基因调控Wnt/β-catenin信号通路对结缔组织病相关的肺间质病变中抗纤维化的机制研究

目的：探讨TGF-β受体Ⅰ（TGFBR1）基因调控Wnt/β-catenin信号通路对结缔组织病相关的肺间质病变（CTD-ILD）的抗纤维化作用。方法：以肺癌的癌旁组织作为正常对照组,Western blot检测CTD-ILD患者肺组织TGFBR1的蛋白表达;人胚肺成纤维细胞系MRC-5分为空白对照组、TGF-β1组、阴性对照组和TGFBR1-siRNA组,各组细胞培养48 h,Western blot检测TGFBR1、Ⅰ型胶原、结缔组织生长因子（CTGF）、α-平滑肌肌动蛋白（α-SMA）、E-钙黏蛋白（E-cad）及Wnt/β-catenin信号通路β 连环蛋白（β-catenin）和c-Myc的蛋白表达;CCK8法检测各组细胞的活力。结果：TGFBR1在CTD-ILD肺组织中的表达显著高于正常肺组织（P<0.05）;与空白对照组比较,TGF-β1组细胞活力、TGFBR1、Ⅰ型胶原、CTGF、α-SMA、β-catenin和c-Myc的蛋白表达均显著升高,E-cad蛋白表达显著降低（P<0.05）;TGF-β1组和阴性对照组细胞活力、TGFBR1、Ⅰ型胶原、CTGF、α-SMA、E-cad、β-catenin和c-Myc的蛋白表达差异均无统计学意义（P＞0.05）;与TGF-β1组比较,TGFBR1-siRNA组细胞活力、TGFBR1、Ⅰ型胶原、CTGF、α-SMA、β-catenin和c-Myc的蛋白表达均显著降低,E-cad蛋白表达显著升高（P<0.05）。结论：TGFBR1基因在CTD-ILD肺组织中表达升高,抑制TGFBR1的表达可通过下调Wnt/β-catenin信号通路降低CTD-ILD纤维化的发生。     

凋亡抑制蛋白Livin和Ki67在胃癌的表达及临床意义

目的探讨凋亡抑制蛋白Livin和Ki67在胃癌的表达及临床意义。方法采用免疫组织化学SP法检测60例胃癌（其中男性44例,女性16例,年龄41～77岁,中位年龄58_3岁）和30例癌旁正常组织中Livin蛋白和Ki67蛋白的表达情况。结果Livin蛋白在胃癌组织中的表达（58．3％）明显高于癌旁正常组织（3.3％）,两者比较差异有统计学意义（P〈0．05）;Livin蛋白的表达与临床分期、病理组织分级和淋巴结转移呈正相关（P〈0．05）;Ki67蛋白在胃癌组织中表达（66．7％）明显高于癌旁正常组织（0％）,两者比较差异有统计学意义（P〈0．05）;Livin蛋白表达与Ki67蛋白表达呈正相关（r=0．482,P〈0．05）。结论Livin蛋白在胃癌组织中表达上调,提示其可能在胃癌发生、发展中起重要作用,有望成为胃癌诊断和基因治疗的新靶点。Livin蛋白和Ki67蛋白可能在胃癌癌变中起协同作用。     

AS、VEGF在胎儿生长受限患者脐血及胎盘部位的表达及意义

目的通过检测脐血与胎盘部位血管生长抑素（angiostatin,AS）、血管内皮生长因子（vascular endotrelial growtr factor,VEGF）的表达,探讨其与胎儿生长受限（fetal growth restriction,FGR）发病的关系。方法取80例产妇（正常妊娠组50例,FGR组30例）分娩后采脐血和胎盘绒毛组织,检测AS、VEGF在脐血中的水平及其在胎盘部位的表达。结果①脐血中：在FGR组AS平均水平显著高于对照组（P〈0.05）;VEGF平均水平显著低于对照组（P〈0.05）。②胎盘中：在FGR组绒毛滋养细胞AS的表达强度较正常对照组显著增强（P〈0.05）,而VEGF的表达降低,差异有统计学意义（P〈0.05）。结论血管生长抑素（AS）与血管内皮生长因子（VEGF）浓度的变化可能在胎儿生长受限（FGR）的发病中起重要作用。     

胃癌患者预后及病理因素与Bmi-1表达的相关性研究

目的： 探讨胃癌组织中Bmi-1蛋白的表达与胃癌患者病理因素及预后的相关性。方法： 收集我院2002-2004年146例有3年以上完整随访资料的胃癌术后患者，采用免疫组织化学法对手术标本石蜡切片进行染色，检测Bmi-1蛋白的表达情况，并分析该蛋白表达对胃癌患者临床病理因素及预后的影响。结果： Bmi-1蛋白在本组胃癌中阳性表达率为67.8%（99/146）。Bmi-1的表达与胃癌大小、临床分期、淋巴结转移和侵润深度密切相关（P<0.05），而与患者的性别、年龄、肿瘤分化程度等无关（P>0.05）。Bmi-1阳性表达者生存率明显低于阴性者（P<0.01）。多因素分析显示，Bmi-1表达、癌侵润深度、淋巴结转移、远处转移、肿瘤大小、术后化疗均为具有显著统计学意义的影响预后的因素。结论： Bmi-1在胃癌组织表达状态与胃癌的生长和侵润转移关系密切，可以作为反映胃癌生物学行为和判断预后的有效指标     

胃癌组织中SIRT-1、VEGF的表达及临床意义

目的探讨胃癌组织中沉默信息调节因子1(SIRT-1)和血管内皮生长因子(VEGF)的表达及临床意义。方法选取2016年6月至2018年6月本院胃癌患者120例,均接受胃癌手术切除术。采用免疫组化检测胃癌组织及其癌旁正常组织中SIRT-1、VEGF的表达。结果胃癌组织SIRT-1、VEGF表达阳性率明显高于癌旁正常组织,差异有统计学意义(P<0.05);胃癌组织SIRT-1、VEGF的表达与TNM分期、浸润深度、浆膜受侵、淋巴结转移有关(P<0.05),与性别、年龄、肿瘤位置、分化程度、肿瘤直径无关(P>0.05);胃癌组织SIRT-1与VEGF表达呈正相关(P<0.05)。结论胃癌组织中SIRT-1、VEGF呈高表达状态,且与胃癌的发生发展有关,可能共同促进了胃癌的生长、侵袭、转移等生物学行为。     

Type 1 protein tyrosine kinases in Chinese breast carcinomas: a clinicopathologic study

Immunostaining for epidermal growth factor receptor (EGFR), c-erbB-2, c-erbB-3, c-erbB-4, ER, and PR was performed in 107 cases of primary breast carcinomas from Anyang, China. The expression rates of EGFR, c-erbB-2, c-erbB-3 and c-erbB-4 in this series were 43.9%, 36%, 27%, and 45.8%, respectively, and a stronger c-erbB-4 staining of "normal" glandular structures inside tumors and in the vicinity of tumor clusters was confirmed. Larger tumor size, lymph node metastases, and higher histologic grade in invasive ductal carcinomas were shown to be statistically valuable negative prognostic factors, and c-erbB-2 expression was also weakly associated with a poor prognosis no matter what the nodal status. The expressions of c-erbB-4 and ER in invasive ductal carcinomas were inversely associated with histologic grade of the tumors. Associations between the expression of c-erbB-4 and ER (p = 0.001) and the expression of ER and PR study (p = 0.004) were found in the present study. No significant associations between the expressions of EGFR, c-erbB-3, c-erbB-4, ER, and PR and overall survival were detected. The expression of c-erbB-4 in the node negative group was, however, associated with a better prognosis, indicating a different role of c-erbB-4 protein in breast tumor development than other EGFR family members have. Int J Surg Pathol 9(3):177-187, 2001     

Hormonal therapy for stomach cancer.

Stomach cancer is one of the major cancers in Asia. Recent advances in diagnosis and surgical techniques have improved the survival of patients with gastric cancer. But radiation and chemotherapy had limited value in promoting the outcome of patients with gastric cancer. Hormonal therapy with tamoxifen had been tried with conflicting results. Previously, we have found that estrogen receptors (ER) were present in 50% cases of Chinese patients with gastric cancers. Recently, the amplification of c-erbB-2 oncogene and its overexpression have been found to correlate with the advancement of lung, ovarian, breast and gastric cancers. In addition, estrogen has been found to inhibit the expression of c-erbB-2 through ER in breast cancer cell lines. A hypothesis is that the same event may occur in ER-positive gastric cancer cell. Thus patients with gastric cancers whose tumors were positive for both ER and c-erbB-2 gene expression, may benefit from estrogen therapy rather than tamoxifen therapy.     

STAT5、VEGF和EGFR在非小细胞肺癌中表达的相关性研究

目的:检测信号转导与转录激活因子5(STAT5)、血管内皮生长因子(VEGF)和表皮生长因子受体(EGFR)在非小细胞肺癌(NSCLC)中的表达情况,探讨三者与NSCLC临床病理特征之间的关系及三者彼此的关系。方法:采用免疫组化(SP法)检测STAT5、VEGF和EGFR在68例NSCLC及26例癌旁正常对照组织中的表达情况。结果:(1)STAT5、VEGF及EGFR在NSCLC组织中的阳性表达明显高于肺正常组织(P<0.05);(2)STAT5的阳性表达与NSCLC组织学类型有关,在腺癌中的表达明显高于鳞癌,与组织分化程度、TNM分期及淋巴结转移无关;(3)VEGF的阳性表达与NSCLC的分化程度、淋巴结转移和TNM分期有关(P<0.01),与NSCLC的组织学类型无关(P>0.05);(4)EGFR的阳性表达与NSCLC的TNM分期和淋巴结转移有关(P<0.01),与NSCLC的组织学类型和分化程度无关(P>0.05);(5)Spearman相关分析显示STAT5、VEGF和EGFR在NSCLC中的阳性表达两两比较(秩和检验方法)均呈正相关。结论:STAT5、VEGF、EGFR可能在肺癌的发生、侵袭和转移中起重要的作用,抑制STAT5信号通路可望成为非小细胞肺癌的治疗靶点。     

大肠癌c—erbB—2,EGFR及p21^ras蛋白共同表达与肿瘤细胞增殖

目的：搪塞ｃ－ｅｒｂＢ－２、ＥＧＦＲ及Ｐ２１＾ｒａｓ癌基因蛋白共同表达对大脾性癌细胞增殖的影响。方法：应用免疫组化ＡＢＣ法检测ｃ－ｅｒｂＢ－２、ＥＧＦＲｅｙ ｐ２１＾ｒａｓ蛋白在６９例大肠癌中的表达情况,同时计数肿瘤细胞ＰＣＮＡ增殖指数。结果：３种癌基因蛋白全部阳性,ｃ－ｅｒｂＢ＿２和ＥＧＦＲ同时阳性及单独ｃ－ｅｒｂＢ－２阳性的大肠癌,癌细胞ＰＣＮＡ指数高于３种蛋白全部阴性组。结果：ｃ－ｅｒｂＢ－     

TWIST、HIF-1α、VEGF在胃癌中的表达及意义

目的:探讨TWIST,HIF-1α和VEGF在人胃癌组织中的表达及与临床病理参数、预后的关系。方法:选择120例胃癌标本,应用SP法免疫组化检测TWIST、HIF-1α和VEGF在人胃癌组织中的表达,分析TWIST、HIF-1α和VEGF的表达与患者临床病理参数之间的关系。结果:胃癌组织及正常胃黏膜组织中均可检测到TWIST、HIF-1α和VEGF的表达,但胃癌组织中的表达水平均明显高于正常胃黏膜组织,表达差异有显著性(P<0.05)。TWIST的表达与浸润深度、肿瘤远处转移及淋巴结转移明显相关(P<0.05)。HIF-1α的表达与肿瘤的分化程度、浸润深度及淋巴结转移呈明显相关性(P<0.05)。VEGF的阳性表达与浸润深度、淋巴结转移及TNM分期有关(P<0.05)。TWIST和(或)HIF-1α阳性表达的患者其5年生存率明显低于其阴性表达的患者。结论:胃癌中TWIST、HIF-1α和VEGF的高表达与胃癌的生物学行为及预后密切相关,检测其表达对预测胃癌的转移及判断预后有一定价值。     

NOTUM基因在胃癌组织中的表达及临床病理意义

目的:检测NOTUM基因在胃癌组织中的表达情况,探讨其与胃癌患者的临床病理关系.方法:收集2014年10月至2015年4月在中国人民解放军总医院普通外科手术治疗的胃癌标本及正常胃黏膜组织80例,采用免疫组织化学方法检测胃癌组织及胃黏膜正常组织中NOTUM基因的表达情况,分析NOTUM基因的表达与患者的临床病理及预后的关系.采用免疫印迹检测NOTUM蛋白及β-catenin蛋白的表达量,使用SPSS进行相关性分析确定NOTUM蛋白与β-catenin蛋白之间的关系.应用Kaplan-Meier方法比较NOTUM阳性表达胃癌患者与阴性表达胃癌患者在术后生存时间的差异.分别采用Log-rank检验和Cox回归模型对可能影响预后的临床病理特征进行单因素和多因素分析.结果:胃癌组织中NOTUM基因的表达显著增加,其表达与淋巴结转移及TNM分期及预后生存相关(P＜0.05),与患者的年龄、性别、肿瘤发生部位、肿瘤大小及肿瘤病理类型无关.胃癌组织中NOTUM基因和β-catenin蛋白的表达呈正相关.在NOTUM基因表达阳性的胃癌患者的生存时间明显缩短.NOTUM基因表达可以作为影响胃癌患者生存的独立危险因素.结论:胃癌中NOTUM基因在胃癌组织中呈高表达,可作为判断胃癌患者疾病进展及预后的生物学标志物.     

Type 1 protein tyrosine kinases in benign and malignant breast lesions

Aims : To determine their significance, we examined the expression pattern of the four epidermal growth factor receptor (EGFR) family members as well as the phosphotyrosine kinase activity in breast tumour tissues.  

Methods and results

Fifty-three malignant breast tumours, four breast cancer cell lines, and 10 benign breast tumours were investigated. Fifty-three per cent (28/53) of the malignant tumours expressed EGFR protein, and the majority of these positive tumours were strongly positive. Eighty per cent (8/10) of the benign tumours also expressed EGFR protein, but all in a lower or moderate level. An association between EGFR expression and increasing malignancy grade was found in the group of infiltrating ductal carcinomas. Of the malignant tumours, 35.8% (19/53) expressed c-erbB-2 protein and 17% (9/53) c-erbB-3 protein, while no expression of c-erbB-2 and c-erbB-3 proteins was found in the benign tumours. Contrary to previous reports, we observed c-erbB-4 receptor protein to be less expressed in the malignant breast tumours. The 'normal' breast epithelial cells adjacent to the malignant tumours and the benign tumours demonstrated intensified membrane staining for c-erbB-4, while a number of the malignant tumours demonstrated a weak cytoplasmic staining or were negative. However, several malignant tumours with strong membrane staining for the c-erbB-4 protein were also found. No simple association between the expression of the four receptors and phosphotyrosine kinase activity was found.  

Conclusion

Our study has revealed a complex expression pattern of the EGFR family members in breast tumour cells. While the data about EGFR, c-erbB-2, c-erbB-3 and phosphotyrosine are largely in line with what has been reported, we found the c-erbB-4 protein expression to be decreased in the malignant tumours.     

A proposal for diagnostically meaningful criteria to classify increased epidermal growth factor receptor and c-erbB-2 gene copy numbers in gastric carcinoma,based on correlation of fluorescence in situ hybridization and immunohistochemical measurements

Amplification of the epidermal growth factor receptor (EGFR) and/or c-erbB-2 oncogenes and overexpression of their proteins are detected in 30% of gastric carcinomas, but there are few reports regarding the correlation between gene amplification and protein overexpression. We examined the correlation between amplification of the EGFR and c-erbB-2 genes, detected using fluorescence in situ hybridization, and overexpression of their proteins, detected using immunohistochemistry, in formalin-fixed tissue sections of 54 surgically resected gastric carcinomas. A mean EGFR copy number per nucleus of four or more and an EGFR/chromosome 7 centromere (CEP7) ratio of 1.7 or more were each detected in 4 specimens (7%). The sensitivity and specificity of both criteria for EGFR protein overexpression were 75% and 92%, respectively. A mean c-erbB-2 copy number per nucleus of 7.0 or more and a c-erbB-2/chromosome 17 centromere (CEP17) ratio of 2.0 or more were detected in six (11%) and eight (15%) specimens, respectively. The sensitivity and specificity of the former criterion to c-erbB-2 overexpression were 83% and 98%, respectively, while those of the latter were 63% and 98%. A mean EGFR gene copy number of 4.0 or more and/or an EGFR/CEP7 ratio of 1.7 and a mean c-erbB-2 gene copy number of 7.0 or more and/or a c-erbB-2/CEP17 ratio of 2.0 or more would be useful in defining increased EGFR and c-erbB-2 gene copy numbers, respectively, in gastric carcinomas.     

Down-regulation of long non-coding RNA LET is associated with poor prognosis in gastric cancer

Introduction: Long non-coding RNAs (lncRNAs) have emerged recently as major players in tumor biology and may be used for cancer diagnosis, prognosis, and potential therapeutic targets. Although down-regulation of lncRNA LET in several cancers has been studied, its role in gastric cancer remains unknown. The aim of our study was to investigate the expression, and clinical significance of lncRNA LET in gastric cancer. Methods: The expression of lncRNA LET was detected by quantitative real-time PCR (qRT-PCR) in pairs of tumor tissues and adjacent non-tumor tissues of 93 gastric cancer patients. Then, we analyzed the potential relationship between lncRNA LET expression levels in tumor tissues and clinicopathological features of gastric cancer, and clinical outcome. Results: We found that lncRNA LET expression was markedly down-regulated in tumor tissues compared with adjacent non-tumor tissues, and associated with depth of invasion, lymph node metastasis, distant metastasis, and TNM stage. Kaplan-Meier analysis showed that patients with low lncRNA LET expression had a poor overall survival than those with high lncRNA LET expression. Moreover, univariate and multivariate analyses showed that low lncRNA LET expression was an independent poor prognostic factor for gastric cancer patients. Conclusions: Our data provided the first evidence that lncRNA LET might be a novel prognostic indicator in gastric cancer and might be a potential target for diagnosis and gene therapy.