【作者】 崔颖；

【导师】 师建国； 闫庆国；

【作者基本信息】 第四军医大学 ， 病理学， 2010， 硕士

【摘要】 研究背景YB-1(Y-box binding protein 1,YB-1)是Y-盒蛋白家族成员之一,是能够特异性结合目的基因启动子和增强子内部Y-box序列(CTGATTGGCCAA)的一类转录因子,也是一类高度保守的顺式作用元件,普遍存在于原核和真核生物细胞中。该类蛋白质具有3个典型的结构域:N末端结构域,富含丙氨酸和脯氨酸,是转录激活结构域;C末端结构域:属亲水结构域,其序列具有酸性和碱性氨基酸富集区交替出现的特点,是蛋白质与蛋白质之间相互作用的结构域;冷休克结构域(cold shock domain, CSD):氨基酸残基序列表现出高度的进化保守性,参与识别和结合DNA和RNA Y-box序列的过程。YB-1是一种多功能蛋白,在转录调节、翻译调控、mRNA选择性剪接、DNA的修复、细胞增殖和再生等过程中发挥多种重要的生物学功能。研究表明,YB-1蛋白在肿瘤的发生、演进、转移、肿瘤细胞耐药性、肿瘤治疗及预后中都发挥着极为重要的作用,而且临床病理研究表明YB-1蛋白在细胞核中的定位可作为肿瘤多药耐药治疗和肿瘤生长的靶标。已证实YB-1异常表达的肿瘤类型有骨肉瘤、前列腺癌、乳腺癌、肺癌、结肠癌、卵巢癌等多种肿瘤。YB-1蛋白的表达在乳腺癌可作为化疗后一种标志物,对选择辅助化疗方案有很大帮助,并且YB-1细胞核定位在包括乳腺癌在内的很多恶性肿瘤中提示预后不良。最近对乳腺癌的研究发现,YB-1通过正调控表皮细胞生长因子受体(Epidermal Growth Factor Receptor,EGFR)的表达,促进乳腺癌细胞的恶性增殖,而抑制YB-1活性对于肿瘤生长具有明显抑制作用。乳腺癌是女性最常见的一种恶性肿瘤,据WHO近年来的调查数据显示,全世界每年约有120万妇女罹患乳腺癌,50万人死于乳腺癌。与欧美等发达国家相比较,临床发现我国乳腺癌呈现出年轻化趋势,但缺乏确切的流行病学统计数据;对青年型乳腺癌组织中YB-1蛋白的表达情况及其与临床分期、病理分型相关性研究尚未见报道;青年性乳腺癌组织中YB-1蛋白表达与乳腺癌分子分型是否有相关性亦属未知。本实验围绕以上三个方面问题展开研究。目的抽样分析我国西部地区乳腺癌发病年龄特征及青年型乳腺癌的发病比例;探讨YB-1蛋白在青年型乳腺癌组织的表达及意义,研究YB-1蛋白表达与ER、PR、HER-2表达及其与临床分期、病理组织学分级等临床病理特征的关系;分析YB-1蛋白表达与乳腺癌分子分型的关系。方法抽样调查1975-2005年30年间西京医院住院诊断乳腺癌患者的发病年龄特征,并与美国SEER(Surveillance Epidemiology End Results, SEER)数据库做类比分析。应用免疫组化研究YB-1、ER、PR、HER-2、CK5/6、EGFR及CD44在青年型乳腺癌组织中的表达,并结合病理组织学类型、病理分级等临床特征分析YB-1在青年型乳腺癌中组织中的表达意义;依据ER、PR、HER-2、CK5/6、EGFR表达对青年型乳腺癌进行分子分型(Luminal-A、Luminal-B、HER2+和Basal-like 4个分子亚型),并分析其与YB-1表达的关系。结果(1)西京医院1975-2005年间住院治疗的3074例乳腺癌患者平均诊断年龄为48.65岁,诊断高峰年龄段为45岁-54岁之间(32.73%),其中<35岁的青年型乳腺癌患者297例(9.67%)。与美国SEER数据库资料显示的美国乳腺癌患者平均诊断年龄61岁、发病高峰年龄段在55岁-64岁、<35岁的青年型乳腺癌患者占总发病人数的1.9%相比,我国乳腺癌患者平均发病年龄较美国明显年轻,高峰诊断年龄段明显前移,诊断年龄段患者比例明显增高,青年型乳腺癌患者所占比例显著增高。(2)HE结果显示64例青年型乳腺癌病理组织学分类主要为浸润性导管癌,占59.4%。免疫组化结果显示64例青年型乳腺癌组织中YB-1阳性表达59例,阳性率为92.2%,其中细胞核阳性表达34例(53.1%),细胞浆阳性表达25例(39.1%);肿瘤>2cm的患者占59.4%,YB-1主要表达在细胞核(40.6%),患者肿瘤≦2 cm占37.5%,YB-1则主要在细胞浆表达(20.3%),YB-1表达类型(核表达/浆表达)与肿瘤大小有显著统计学意义(P=0.036);组织学3级所占比例最高,占48.4%,且多为YB-1细胞核表达(37.5%),乳腺癌不同的组织学分级间YB-1的表达不同(P=0.000);青年型乳腺癌患者发生淋巴结转移的比例高(84.4%),其中N3期所占比例最高,占40.6%,YB-1主要在细胞核表达,占31.3%,胞浆表达占7.8%;N2期次之,占总例数的23.4%,YB-1主要在细胞浆表达,占17.2%;N1期比例最少,仅为9.4。(3)青年型乳腺癌分子分型中主最多见的是Luminal-B型,占46.9%,其次为Luminal-A型,占25%,HER-2型与Basal-like型均占10.9%,其它类型6.3%。Luminal-B型中YB-1主要表达在细胞核(32.8%),浆表达仅占9.4%,统计分析显示YB-1表达的核浆分布特点与青年型乳腺癌分子分型有关(P=0.009)。结论(1)与美国SEER数据库中美国乳腺癌的数据相比较,中国西部地区乳腺癌平均诊断年龄和诊断高峰年龄段明显提前,且青年型乳腺癌患者比例明显增高。(2) YB-1在青年型乳腺癌组织中的表达特点与肿瘤大小、病理组织分级及淋巴结状态有一定关系,细胞核阳性主要见于肿瘤>2cm的患者,而细胞浆阳性主要见于肿瘤≦ 2cm的患者,且YB-1细胞核表达主要为组织学3级,且青年型乳腺癌淋巴结转移率高。(3)青年型乳腺癌不同分子分型中YB-1蛋白表达存在差异,YB-1可能成为青年型乳腺癌防治的新的分子靶点。更多还原

【Abstract】 IntroductionThe mammalian Y-box binding protein-1(YB-1) , belonging to a family of multifunctional proteins conserved from prokaryote to eucaryon , is one of proteins involved in transcriptional and translational regulation of a wide range of genes by specific binding of Y-box sequence (5’-CTGATTGGCCAA-3’) in their promoters and enhancers. A typical Y-box binding protein contains three structure domains: the N-terminal domain is rich in alanine and proline which have transcriptional activation; the C-terminal domain consists of alternating basic and aromatic regions which have high hydrophilicity; the center cold shock domain (CSD) is highly conserved within the family of Y-box binding proteins. The CSD is involved in specific and non-specific RNA binding, and in specific DNA binding, which binds strongly to inverted CCAAT box. YB-1 is a multifunctional protein may expressed and involved in fundamental processes such as transcription, translation, mRNA splicing, DNA repair, cell proliferation and regeneration.Several laboratories have demonstrated that YB-1 play an important role in malignant tumorigenesis, aggressiveness, metastasis, multidrug resistance, chemotherapy and prognosis. Clinical pathologic researchers claimed that the nuclear localization of YB-1 could be an important therapeutic target against not only multidrug resistance but also tumor growth. Some studies showed that the expression of YB-1 can be found in many human malignant tumors such as osteosarcoma, prostate cancer, breast cancer, lung cancer, colon carcinoma and ovarian cancer etc. Particularly in prostate cancer and breast cancer. The expression of YB-1 in breast cancer patients who were treated with chemotherapy in can act as a molecular marker in clinical chemo-treatment. And nuclear expression of YB-1 is often associated with poor prognosis in various human malignancies, including breast cancer. In recent studies, scientists determined that YB-1 facilitated malignant tumor proliferation by positively regulated epidermal growth factor receptor (EGFR). And to suppress the expression of YB-1 can obviously inhibit the tumor growth. Breast cancer is very common in human malignant tumor and is the number one in female cancers. The data from World Health Organization (WHO) showed that there were about 1.2 million women suffering from breast cancer around the world every year, and 500000 died from breast cancer. The diagnosis ages of breast cancer in China seems younger than that in developed nation such as USA and European countries.While in clinical work pathologist found the age of breast cancer patients younger than American and European breast cancer patients.However, there were short of epidemiologic study for this. Besides, there is no research has been found about the relationship between the expression of YB-1 and clinical characteristics and molecular subtypes in young breast cancer. ObjectiveIn order to analysis the diagnostic age of breast cancer and find the percentage of young breast cancer patients in west regions of China; To investigate the expression and significance of YB-1protein in human young breast cancer; To analyze the relativity between YB-1 and ER, PR, HER2 and cilinical characteristics in human young breast cancer; To analysis the expression of YB-1protein between molecular subtypes in young breast cancer patients.MethodsThe clinical records of the patients with breast cancer from 1975 to 2005(30 years) were gathered in Xijing Hospital. The diagnostic age of breast cancer was analyzed and compared with data from Surveillance Epidemiology End Results(SEER)of the USA.The expression of YB-1, ER, PR, HER-2, CD44, CK5/6 and EGFR in human young breast cancer were studied by immunohistochemistry (IHC);The relationship between YB-1expression and significance with clinical characteristics as histologic type, histopathologic grading, tumor size and lymph node status were analyzed; Four different molecular subtypes of breast cancer(Luminal-A, Luminal-B,HER-2 and Basal-like) were defined by IHC markers of estrogen receptor (ER), progesterone receptor (PR), HER2 and CK5/6. And the relationship between the expression of YB-1 and can the molecular subtypes of breast cancer was also analyzed.Results(1) The epidemiologic statistics showed that the average diagnostic age of breast cancer among 3074 cases of breast cancer patients in Xijing hospital from 1975-2005 was 48.65. The peak period was from 45 to 54, among which there were 1006 patients and occupied 32.73%. There were 297 patients who were younger than 35 years old, which occupied 9.67%. Compared with data in SEER, there was an obvious difference between Chinese and American among the breast cancer patients on both of the diagnostic age and the distribution of whole diagnostic age. (2)The expression of YB-1 protein in tissues of young breast cancer patients (<35 years): the positive rate of YB-1 were 92.2% (59/64), among which nucleus staining rate were 53.1% (34/64), cytoplasm staining rate were 39.1% (25/64). When the tumor size >2cm that YB-1 were mainly stained in nucleus (40.6%); on the contrary, when the tumor size≦2cm that YB-1 were mainly stained in cytoplasm (20.3%). There were significant correlation between YB-1 expression paterns and tumor size (P=0.036). In all cases of breast cancer the main histopathologic type is grade 3.Interestingly, in this group YB-1 stained mainly in nucleus(37.5%). There were significant different expression paterns of YB-1 in different histopathologic grade of breast cancer (P=0.000). Our study showed that there were higher metastasis rate of lymph node (84.4%) among these young breast cancer patients. (3) Among all 64 young breast cancer patients, the subtype of Luminal-B was the majority (46.9%) and the next were Luminal-A (25%). YB-1 primarily expressed in nucleus (32.8%) in the subtype of Luminal-B and cytoplasm expression was only 9.4%. In HER-2 and Basal-like subtypes YB-1 expressed at a same percentage (10.9%). There were different expression paterns of YB-1 in different molecular subtypes (P=0.009)..Conclusions(1)Compared with data in SEER both of the average diagnostic age and peak period of breast cancer in west regions of China were younger than that in the USA. The percentage of young breast cancer patients in west regions of China is much higher than that in USA.(2)The expression paterns of YB-1 in young breast cancer were related with the histopathologic characteristics such as tumor size, histopathologic grading and lymph node status.(3)There were different kinds of expression of YB-1 among different molecular subtypes in young breast cancer. YB-1 maybe can be used as a new molecular target in the prevention and therapy in young breast cancer.更多还原