Estrogen receptor-negative and human epidermal growth factor receptor 2-negative breast cancer tissue have the highest Ki-67 labeling index and EGFR expression: gene amplification does not contribute to EGFR expression

Estrogen receptor (ER) and human epidermal growth factor 2 (HER2) are well-investigated molecules and the focus of many breast cancer therapies. There is a group of breast cancers lacking ER and HER2, but it is not fully understood. Treatment for these patients is limited to cytotoxic chemotherapy. The purpose of present study is to examine ER(-)/HER2(-) breast cancers, with a particular focus on epidermal growth factor receptor (EGFR). EGFR is a target molecule for which novel medicines have been recently developed for other organ cancers, however biological significance in breast cancer is not yet well demonstrated. Breast cancer specimens (n=58) were categorized into four groups: i) ER(+)/HER2(-) (51.7%); ii) ER(+)/HER2(+) (8.6%); iii) ER(-)/HER2(+) (20.7%); and iv) ER(-)/HER2(-) (19.0%). They were immunohistochemically (IHC) examined using antibodies for EGFR, platelet derived growth factor receptor (PDGFR)alpha, PDGFRbeta, parathyroid hormone (PTH) receptor, Ki-67, cyclinD1, p53, and vimentin. The Ki-67 labeling index (LI) was highest in ER(-)/HER2(-) (36.5%), and decreased in order from ER(-)/HER2(+) (31.4%), ER(+)/HER2(+) (17.7%), to (ER(+)/HER2(-) (15.9%) (p=0.001). EGFR, p53 and vimentin were highly expressed in ER(-)/HER2(-) breast cancer cells (p<0.01). CyclinD1 was inversely expressed to Ki-67 LI (p<0.001). Gene amplification of EGFR was examined by two in situ hybridization techniques, fluorescence in situ hybridization (FISH) and chromogenic in situ hybridization (CISH) in serial sections to IHC. Only 1 of 14 EGFR-positive breast cancers showed gene amplification at low levels by CISH. Overall, the ER(-)/HER2(-) breast cancer showed the highest Ki-67 LI, the most frequent expression of EGFR, p53 and vimentin, as well as the lowest expression of cyclinD1. It is unlikely that gene amplification contributes to EGFR expression. ER(-)/HER2(-) breast cancers have potential in the development of novel therapeutics, including targeted medicines.     

Epidermal growth factor receptor (EGFR) and the estrogen receptor modulator amplified in breast cancer (AIB1) for predicting clinical outcome after adjuvant tamoxifen in breast cancer

The epidermal growth factor receptor (EGFR) and the estrogen receptor (ER) modulator Amplified In Breast cancer-1 (AIB1) have been reported to be of importance for the prognosis of breast cancer patients. We have analyzed AIB1 and EGFR by immunohistochemistry in primary breast cancers (n = 297) arranged in a tissue microarray in order to predict outcome after adjuvant endocrine therapy with tamoxifen for two years. High expression of AIB1 was associated with DNA-nondiploidy, high S-phase fraction, HER2 amplification, and short term (相似文献   

YB-1在青年型乳腺癌组织中的表达及意义

目的:探讨YB-1(Y-box binding protein 1)在青年型乳腺癌组织中的表达及意义。方法:应用免疫组织化学方法研究YB-1蛋白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在青年型乳腺癌组织中的表达意义;依据ER、PR、HER-2、CK5/6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: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阳性率为92.2%,其中细胞核阳性表达率53.1%,细胞浆阳性表达率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?2cm占37.5%,YB-1则主要在细胞浆表达(20.3%),YB-1表达类型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的表达率不同(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%。青年型乳腺癌分子分型中主最多见的是Luminal-B型,占46.9%,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=0.04)。结论: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,YB-1主要在细胞核表达;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。     

Prognostic implications of the nuclear localization of Y-box-binding protein-1 and CXCR4 expression in ovarian cancer: their correlation with activated Akt, LRP/MVP and P-glycoprotein expression

The nuclear localization of Y-box-binding protein-1 (YB-1) is known to be a poor prognostic factor in several human malignancies, including ovarian carcinoma. Following on from our basic study dealing with microarray analyses of YB-1-associated gene expression in ovarian cancer cells, we examined whether nuclear localization of YB-1 is associated with the expression of CXCR4, a vault protein named lung resistance-related vault protein (LRP/MVP), phosphorylated Akt (p-Akt) or P-glycoprotein (P-gp) in human ovarian carcinoma. Fifty-three surgically resected ovarian carcinomas treated with paclitaxel and carboplatin were examined immunohistochemically for nuclear YB-1 expression and intrinsic expression of p-Akt, P-gp, LRP/MVP and CXCR4. Nuclear expression of YB-1 demonstrated significant correlation with p-Akt, P-gp and LRP expression, but no relationship with CXCR4 expression. By multivariate analysis, only YB-1 nuclear expression and CXCR4 expression were independent prognostic factors with regard to overall survival. These results indicate that YB-1 nuclear expression and CXCR4 expression are important prognostic factors in ovarian carcinoma.     

乳腺癌组织HR与HER-2和SATB1表达相关性研究

目的：检测乳腺癌组织中激素受体（hormonereceptor,HR）、人表皮生长因子受体2（humanepidermalgrowthfactOrreceptor2,HER-2）和特异性核基质结合蛋白（specialATrichsequencebindingprotein1,SATB1）的表达,探讨HR与HER-2、SATB1及临床病理参数的关系。方法：应用免疫组织化学方法检测乳腺癌患者雌激素受体（estrogenre-ceptor,ER）、孕激素受体（progesteronereceptor,PR）、HER-2及SATB1蛋白的表达,荧光原位杂交方法检测HER-2基因扩增状态,统计学方法分析HR（包括ER及PR）的表达与HER-2、SATB1及临床病理参数之间的相关性。结果：乳腺癌组织ER及PR的表达均与患者年龄正相关（r=0．286,P=0．010;r=0．249,P=0．026）,ER的表达与肿瘤分级负相关（r=-0．306,P=0．006）;ER及PR的表达与肿瘤大小、组织学类型、淋巴转移情况及TNM分期均无明显相关性,P值均〉0．05。HR的表达与SATB1、HER-2及SATB1／HER2双阳性表达均呈负相关关系（r=-0．248,P=0．027;r=-0．392,P〈0．001;r=-0．150,P〈0．001）。结论：HR阳性患者治疗及预后相对较好;乳腺癌组织HR的表达与HER-2和SATB1呈负相关关系,三者之间可能存在相互联系的信号通路。     

Alteration of Y-box binding protein-1 expression modifies the response to endocrine therapy in estrogen receptor-positive breast cancer

Y-box binding protein-1 (YB-1) plays an important role in tumor progression and drug resistance. This study examined whether YB-1 is involved in the alteration of response to endocrine therapy in estrogen receptor (ER)-positive breast cancer cells. MCF7 cells that stably expressed YB-1 (MCF7-YB-1) and vector control cells (MCF7-vector) were established. These cells were used to analyze the expression of the factors related to ER and growth factor receptor signaling pathways and responses to antiestrogens (tamoxifen and fulvestrant) and estrogen responsive element (ERE) activity. The effect of knocking down endogenous YB-1 expression was tested in wild-type MCF7 cells. In addition, the expression of YB-1 and the factors related to ER and growth factor receptor signaling pathways were evaluated in clinical breast cancers treated with preoperative chemotherapy. The expression of HER2, AIB1, p-Erk, and c-Myc was increased in MCF7-YB-1 cells. In contrast, knocking down of YB-1 decreased the expression of these factors but increased the expression of ERα in wild-type MCF7 cells. Furthermore, sensitivity to antiestrogens was decreased in the MCF7-YB-1 in comparison to that in MCF7-vector cells. The introduction of YB-1 into MCF7 cells inhibited apoptosis and cell cycle arrest at G1 phase induced by antiestrogens. In MCF7-YB-1 cells, the expression levels of p-Erk and c-Myc were continuously upregulated when cells were treated with either tamoxifen or fulvestrant. The ERE activity was reduced in MCF7-YB-1 cells in comparison to MCF7-vector cells, and the ERE activity in MCF7-YB-1 cells was inhibited by fulvestrant at a lower concentration than that which inhibited the ERE activity in MCF7-vector cells. In ER-positive clinical breast cancers treated with preoperative chemotherapy, significantly more number of specimens that showed increased or positive YB-1 expression after chemotherapy was positive for HER2 expression. These data suggest that alteration of YB-1 may modify the crosstalk between the ER pathway and HER2 pathway in ER-positive breast cancer cells, and consequently, may alter the response to endocrine therapy in ER-positive breast cancer cells.     

In ovarian cancer the prognostic influence of HER2/neu is not dependent on the CXCR4/SDF-1 signalling pathway

HER2/neu overexpression is a driving force in the carcinogenesis of several human cancers. In breast cancer the prognostic influence of HER2/neu was shown to be at least partly based on increased metastatic potential mediated by the chemokine-chemokine receptor pair SDF-1(CXCL12)/CXCR4. We wanted to evaluate the influence of HER2/neu on ovarian cancer prognosis and to investigate whether compromised survival would correlate with CXCR4 expression and/or SDF-1 abundance. Therefore, we analysed HER2/neu, CXCR4, and SDF-1 in 148 ovarian tumour samples by means of immunohistochemistry on tissue microarrays. Overexpression of HER2/neu was found in 27.6% of ovarian cancer tissues and in 15% of ovarian borderline tumours. In ovarian cancer patients, overexpression of HER2/neu correlated closely with overall survival (univariate hazard ratio (HR) 2.59, P=0.005; multiple corrected HR 1.92, P=0.074). In contrast, CXCR4 expression and SDF-1 abundance had no impact on overall survival, and both parameters were not correlated with HER2/neu expression. As expected, cytoplasmic CXCR4 expression and SDF-1 abundance correlated closely (P<0.0001). Our results confirm a univariate influence of HER2/neu expression on overall survival, which was completely independent of the expression of CXCR4 and the abundance of SDF-1, implying significant differences between the HER2/neu downstream pathways in ovarian cancer compared with breast cancer.     

Y-box factor YB-1 predicts drug resistance and patient outcome in breast cancer independent of clinically relevant tumor biologic factors HER2, uPA and PAI-1.

Intrinsic or acquired resistance to chemotherapy is responsible for failure of current treatment regimens in breast cancer patients. The Y-box protein YB-1 regulates expression of the P-glycoprotein gene mdr1, which plays a major role in the development of a multidrug-resistant tumor phenotype. In human breast cancer, overexpression and nuclear localization of YB-1 is associated with upregulation of P-glycoprotein. In our pilot study, we analyzed the clinical relevance of YB-1 expression in breast cancer (n = 83) after a median follow-up of 61 months and compared it with tumor-biologic factors already used for clinical risk-group discrimination, i.e., HER2, urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1). High YB-1 expression in tumor tissue and surrounding benign breast epithelial cells was significantly associated with poor patient outcome. In patients who received postoperative chemotherapy, the 5-year relapse rate was 66% in patients with high YB-1 expression. In contrast, in patients with low YB-1 expressions, no relapse has been observed so far. YB-1 expression thus indicates clinical drug resistance in breast cancer. Moreover, YB-1 correlates with breast cancer aggressiveness: in patients not treated with postoperative chemotherapy, those with low YB-1 expression are still free of disease, whereas the 5-year relapse rate in those with high YB-1 was 30%. There was no significant correlation between YB-1 expression and either HER2 expression or uPA and PAI-1 levels. Risk-group assessment achieved by YB-1 differed significantly from that by HER2 or uPA/PAI-1. In conclusion, YB-1 demonstrated prognostic and predictive significance in breast cancer by identifying high-risk patients in both the presence and absence of postoperative chemotherapy, independent of tumor-biologic factors currently available for clinical decision making.     

CCR7 and CXCR4 as novel biomarkers predicting axillary lymph node metastasis in T1 breast cancer.

PURPOSE: The chemokine receptors CCR7 and CXCR4 have been shown to play an important role in cancer metastasis. We therefore studied the differential expression of CCR7 and CXCR4, along with that of the biomarker HER2-neu, to evaluate whether these biomarkers could predict axillary lymph node metastasis in breast cancer. EXPERIMENTAL DESIGN: Biomarker expression levels were evaluated using paraffin-embedded tissue sections of lymph node-negative (n = 99) and lymph node-positive (n = 98) T1 breast cancer by immunohistochemical staining. RESULTS: Lymph node-positive tumors showed higher rates of high cytoplasmic CCR7 staining (21.5% versus 8.5%, P = 0.013) and HER2-neu overexpression (21.5% versus 9.3%, P = 0.019) than did lymph node-negative tumors. Similarly, high cytoplasmic CXCR4 expression occurred more commonly in lymph node-positive tumors (11.2% versus 5.1%, P = 0.113). In contrast, predominantly nuclear CXCR4 staining was more likely to be found in lymph node-negative tumors (54.5% versus 37.8%, P = 0.018). Furthermore, cytoplasmic CXCR4 coexpressed with HER2-neu was the only factor associated with involvement of four or more lymph nodes (16.7% versus 1.2%, P = 0.04) among lymph node-positive tumors. When all three biomarkers (CCR7, CXCR4, HER2-neu) were utilized together, 50.0% of lymph node-positive tumors highly expressed one of these biomarkers compared with 18.8% of the lymph node-negative tumors (P < 0.0001). CONCLUSIONS: Our results suggest that the chemokine receptor CCR7 is a novel biomarker that can predict lymph node metastases in breast cancer. Utilization of additional markers, such as CXCR4 and HER2-neu, further improves the prediction of the presence and extent of lymph node involvement.     

CXCR4表达上调与HER2介导乳腺癌转移的相关性研究

背景与目的： 检测CXCR4和HER2在乳腺患者的表达水平,观察HER2特异性抗体Herceptin对CXCR4表达和乳腺癌细胞体外转移活性的抑制作用。 材料与方法： 采用免疫组化法,检测临床不同时期乳腺癌组织CXCR4和HER2的表达水平;采用Western blot检测Herceptin作用后CXCR4蛋白表达,RT_PCR技术检测CXCR4 mRNA的表达;采用趋化实验和粘附实验检测Herceptin对HER2不同表达水平的乳腺癌细胞趋化和粘附活性的影响。 结果： CXCR4表达与乳腺癌细胞淋巴结转移状况、乳腺癌组织学分期及HER2的表达呈正相关(P值分别为0.032、0.000和0.015);在高表达HER2的乳腺癌细胞株SKBR3中,Herceptin可下调CXCR4的蛋白及mRNA的表达(P<0.05),并抑制其趋化和粘附活性(P<0.05)。 结论： 在HER2介导的肿瘤转移中,CXCR4表达上调可能是关键因素。     

The prognostic significance of transforming growth factors in human breast cancer.

Transforming growth factor alpha (TGF alpha) and Transforming growth factor beta-1 (TGF-beta 1) are growth regulatory for breast cancer cell lines in vitro and several studies have suggested that levels of the receptor for TGF alpha, the epidermal growth factor (EGFR) in tumour biopsies predict relapse and survival. We have examined the prognostic significance of TGF alpha, TGF-beta 1 and EGFR mRNA expression in a series of patients with primary breast cancer with a median follow up period of 60 months. In 167 patients the expression of TGF-beta 1 was inversely correlated with node status (P = 0.065) but not ER status, tumour size or menopausal status. Patients with high levels of TGF-beta 1 had a longer disease free interval with a significantly longer probability of survival at 80 months although the overall relapse free survival was not increased. EGFR mRNA expression was measured in 106 patients and was inversely correlated with ER status (P = 0.018). EGFR levels did not predict for early relapse or survival. TGF alpha mRNA levels were measured in 104 patients, no correlation was seen tumour size, node status, Er status, or clinical outcome.     

The Significance of CXCR4 Expression for the Prediction of Lymph Node Metastasis in Breast Cancer Patients

OBJECTIVE The chemokine receptor(CXCR4)CXC chemokine receptor 4)plays an important role in cancer metastasis.We therefore studied differential expression of the CXCR4,as well as that of the biomarker HER2,so as to evaluate whether these biomarkers can be used to predict axillary lymph node metastasis in breast cancer patients. METHODS Immunohistochemistry was used to evaluate the CXCR4 and HER2 expressions and to examine the paraffin sections of the breast cancers at various stages.Positive lymph node expression was found in 80 of the cases,and in 7 there was negative expression. RESULTS Compared to the cases with negative lymph nodes, there was a high expression of CXCR4(26.3% vs.14.3%,P=0.013), and an over-expression of HER2(28.8% vs.14.3%,P=0.011). Moreover,there was a direct correlation between the CXCR4 and HER2 expressions and the tumor staging(P=0.000)and lymph node metastasis(P=0.032).When the two biomarkers,i.e.CXCR4 and HER2,were concurrently labeled,a high expression of one of the biomarkers could be seen in the cases with positive lymph nodes(51.3% vs.28.6%,P<0.003). CONCLUSION The chemokine receptor,CXCR4,is a new-type biomarker in predicting axillary lymph-node metastasis in breast cancers.Compared with the other markers,such as HER2 etc., assessment of CXCR4 can improve the prediction of the presence and extent of lymph node involvement.     

Loss of breast cancer metastasis suppressor 1 protein expression predicts reduced disease-free survival in subsets of breast cancer patients.

PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors.     

Nuclear HER3 is associated with favorable overall survival in uveal melanoma

HER3 is a member of the epidermal growth factor receptor (EGFR) family and is expressed in several types of cancer. Both the cytoplasmic and nuclear appearances of the receptor have been reported. Here, we investigate the expression and subcellular distribution of HER3 in uveal melanoma (UM) cells and tissues and its potential impact on clinical outcome of patients. Paraffin-embedded samples from 128 consecutive UM patients, enucleated without alternative treatment on UM diagnosis, were evaluated for HER3 using immunohistochemistry. Immunoreactivity was scored for frequency, intensity of positive cells, and subcellular distribution. The results were correlated with the established clinicopathological parameters using univariate and multivariate statistical analyses. HER3 expression was shown in 70% of the cases (89/128). This contrasts with the other EGFR family receptors (EGFR, HER2 and HER4) that are infrequently expressed in UM. Surprisingly, HER3 was found to be localized solely in the cell nuclei in 56 cases. The remaining 33 HER3 positive cases showed diffuse distribution (cytoplasmic ± nuclear). Nuclear HER3 was independently correlated with a more favorable overall survival (p = 0.043 and hazard ratio = 0.618) compared to cases with diffuse and/or no HER3. Nuclear localization of HER3 was also confirmed in fresh UM material and in UM cell lines. In conclusion, HER3 is frequently localized solely in the cell nuclei in UM and as such it predicts a more favorable overall survival.     

Correlates and determinants of nuclear epidermal growth factor receptor content in an oropharyngeal cancer tissue microarray.

BACKGROUND: We have previously reported nuclear localization of epidermal growth factor receptor (EGFR) protein in oropharyngeal cancer tissue. Nuclear EGFR levels were inversely correlated with survival and response to radiotherapy. Here, we sought to identify the determinants and correlates of nuclear EGFR content. METHODS: We analyzed an oropharyngeal cancer tissue microarray for the expression of the key molecules of the EGFR signaling cascade using an automated image analysis technique (AQUA) scored on a scale of 0 to 255, which permits protein quantitation and subcellular localization. Patients with oropharyngeal squamous cell cancer treated with radiotherapy or surgery and radiotherapy were eligible. Data were analyzed using Spearman correlations and multiple linear regression with robust SEs. RESULTS: Of the 95 tumors included in this study, 72 (75%) had sufficient tissue for analysis of nuclear EGFR. Nuclear EGFR levels were associated with membranous/cytoplasmic EGFR levels (rho = 0.82, P < 0.001), nuclear extracellular signal-regulated kinase-2 (rho = 0.30, P = 0.01), and nuclear proliferating cell nuclear antigen (PCNA; rho = 0.36, P = 0.003). Nuclear phosphorylated-Akt, cyclin D1, phosphatase and tensin homolog (mutated in multiple cancers 1) (PTEN), p53, and proliferation marker Ki-67 levels did not correlate with nuclear EGFR level. In multivariable analysis, only PCNA retained its significant association (P = 0.01). CONCLUSIONS: These results are consistent with preclinical data showing that EGFR may function as a tyrosine kinase in the nucleus, phosphorylating and stabilizing PCNA. The nuclear activity of EGFR may constitute a novel therapeutic target.     

The role of CXCR4 receptor expression in breast cancer: a large tissue microarray study

Summary The chemokine receptor CXCR4 is an important factor in the migration, invasiveness, metastasis and proliferation of breast cancer cells. We have retrospectively analyzed the levels of expression of CXCR4 in a large cohort of breast cancers and pre-invasive breast samples linked to clinical data. A total of 1808 invasive breast carcinomas and 214 pre-invasive breast samples could be analyzed in correlation with basic clinico-pathological data such as hormone receptor status, HER2 status and tumor grade. The majority of breast cancers expressed either nuclear or cytoplasmic staining or both. CXCR4 cytoplasmic expression was associated with parameters of tumor aggressivity (tumor grade and lymph node status) and had prognostic value (age-adjusted hazard ratio=1.73; Confidence Interval: 1.07–2.77) with respect to disease-specific survival. CXCR4 positivity in the cytoplasm but not the nucleus was associated with HER2 expression and amplification as well as with hormone receptor negativity (both ER and PR). The percentage of nuclear staining increased from normal breast tissue (20%) to ductal carcinoma-in-situ DCIS (43%) to invasive cancer (67%) while CXCR4 was expressed in the cytoplasm of 67% of (DCIS) cases (double that in normal breast samples), suggesting an important role in breast tumor progression. The CXCR4 receptor is expressed in many breast cancers, justifying its development as a therapeutic target in breast cancer patients. Its cytoplasmic expression is associated with breast tumor progression, suggesting potential value as a diagnostic marker.