Factor In Human Breast Cancer Research Articles

The role of DDX46 in breast cancer proliferation and invasiveness: A potential therapeutic target.

DDX46, a member of DEAD-box (DDX) proteins, is associated with various cancers, while its involvement in the pathogenesis of breast cancer hasn't been reported so far. The study demonstrated the overexpression of DDX46 in human breast cancer cells and tissue samples, and correlated with high histological grade and lymph node metastasis. Downregulation of DDX46 in the breast cancer cell lines inhibited their proliferation and invasiveness in vitro. Furthermore, the growth of MDA-MB-231 xenografts was suppressed in nude mice by DDX46 knockingdown. Taken together, our findings suggest that DDX46 is an oncogenic factor in human breast cancer, and a potential therapeutic target.

ALKBH family members as novel biomarkers and prognostic factors in human breast cancer.

Breast cancer is the most common lethal carcinoma worldwide and better targeted therapies are still worthy of exploration, having had some great successes already. Abnormal expression of ALKBH members were found in various cancers, and the roles played by it were the focus of attention. The ALKBH gene family encodes nine homologous enzymes (ALKBH1-8 and FTO) to repair DNA or RNA depending on Fe2+ and α-ketoglutarate (α-KG), which is related to carcinogenesis. In this study, we applied several databases to explore the roles of ALKBHs in breast cancer. We found that ALKBH members were abnormal expression in breast cancer and associated with tumor stage and subclasses. Higher alteration rates of ALKBH family were found in breast cancer. Function enrichment revealed that several cancer-associated signal pathways were related to ALKBH family such as PI3K-Akt signaling pathway and axon guidance. Infiltration of immune cells (Eosinophiles, NK CD56bright cells, mast cells, T helper cells and so on) were strongly related to ALKBHs. Moreover, we further found that there was strong correlation between ALKBH7 and higher age, later T stage, ER/PR positive and post-menopause of breast cancer patients, and patients with higher ALKBH7 expression had shorter overall survival (OS) and post progression survival (PPS). In conclusion, our findings may provide novel insights into ALKBH-targeted therapy for breast cancer patients, and ALKBH7 may be a potential prognostic biomarker.

Comprehensive Analysis of Prognostic and immune infiltrates for FOXPs Transcription Factors in Human Breast Cancer

Forkhead-box-P family include FOXP1/2/3/4 and its clinical significance still remains unclear in breast cancer (BRCA). We analysed the expressions of FOXPs in BRCA patients to determine diagnostic and prognostic values. Our results indicated that the transcriptional levels of FOXP3/4 were up-regulated in BRCA patients, but FOXP2 were down-regulated. No statistically significant correlation were found between the expression levels of FOXPs in Pathologic stage. FOXP2/3 had a significantly high AUC value in the detection of breast cancer, with 96.8% or 95.7% in accuracy respectively. Our study also suggested that BRCA patients with high transcription levels of FOXP1/2/4 were significantly associated with longer Overall Survival (OS). In contrast, BRCA patients with high transcription level of FOXP3 was not statistically related with OS. Our work revealed that FOXPs were closely related to the alteration of extensive immune checkpoints in breast invasive carcinoma. Additionally, FOXP3 has a significant positive correlation with PDCD1, CD274, CTLA4 and TMB in breast cancer, and FOXP3 expression showed a statistically significant correlation with infiltration of immune cells. Finally, we found that FOXP3 expression predicted the breast cancer cells response to anticancer drugs. Altogether, our work strongly suggested that FOXPs could serve as a biomarker for tumor detection, therapeutic design and prognosis.

Downregulation of hsa_circ_0006220 and its correlation with clinicopathological factors in human breast cancer.

Circular ribonucleic acids (circRNAs) are highly stable and conserved forms of RNAs present in all eukaryotes. They can modulate the expression of genes by sponging specific micro RNAs (miRNAs), thereby affecting various disease processes. However, their expression pattern in human breast cancer has not been elucidated. In this study, differentially expressed circRNAs in breast cancer tissues and paired noncancerous tissues were analyzed using an Arraystar Human circRNA Microarray, and hsa_circ_0006220 was selected for its 27-fold downregulation in breast cancer tissues. Its expression was also verified in 50 breast cancer and paired noncancerous tissues using real-time polymerase chain reaction (RT-PCR). An analysis of the expression of hsa_circ_0006220 and the clinicopathological factors in breast cancer was conducted. A receiver operating characteristic (ROC) curve of hsa_circ_0006220 was constructed. The interaction between hsa_circ_0006220 and five possible target miRNAs was predicted, and their expression were verified when overexpressing hsa_circ_0006220 by RT-PCR. Hsa_circ_0006220 was found to be significantly downregulated in breast cancer tissues compared to the paired noncancerous tissues by microarray and RT-PCR. The expression of hsa_circ_0006220 was significantly inversely correlated with histological type (P=0.0028) and lymph node metastasis (P=0.0341). The area under the ROC curve (AUC) was 0.706. Five miRNAs that might be sponged by hsa_circ_0006220 were predicted. MiR-197-5p was significantly downregulated after overexpression of hsa_circ_0006220. Our results indicated that hsa_circ_0006220 may play a role in human breast cancer and might be a potential tumor marker for breast cancer screening.

Gas6 expression is reduced in advanced breast cancers

Growth arrest-specific gene 6 (Gas6) is a cytokine that binds to receptor tyrosine kinases Tyro3, Axl, and Mer. Numerous studies have suggested that macrophage-derived Gas6 interacts with Axl to promote cancer progression, and Axl has been associated with poor clinical outcome. However, the expression and relevance of Gas6 in human breast cancer patients has not been studied. Analysis of tissue microarrays showed that Gas6 was highly expressed in ductal carcinoma in situ (DCIS) but markedly decreased in invasive breast cancer. Gas6 and Axl were weakly correlated, suggesting that their functions may not exclusively rely on each other. Analyses of publicly available databases showed significantly improved overall and relapse-free survival in patients with high Gas6 mRNA, particularly in luminal A breast cancers. These findings indicate that tumor-derived Gas6 is not overexpressed in invasive breast cancer, and may not be a negative prognostic factor in human breast cancer.

Expression of RET is associated with Oestrogen receptor expression but lacks prognostic significance in breast cancer

BackgroundThe Rearranged during Transfection (RET) protein is overexpressed in a subset of Estrogen Receptor (ER) positive breast cancer, with both signalling pathways functionally interacting. This cross-talk plays a pivotal role in the resistance of breast cancer cells to anti-endocrine therapies, and RET expression is assumed to correlate with poor prognosis based on findings in small patient cohorts. The aim of our study was to investigate the impact of RET expression on patient outcome in human breast cancer.MethodsWe performed an immunohistochemical analysis of RET protein expression on a tissue microarray encompassing 990 breast cancer patients and correlated its expression with clinicopathological parameters and survival data.ResultsExpression of RET was detected in 409 out of 990 cases (41.3%). RET and ER expression significantly correlated (p < 0.0001). The Luminal B HER2-positive subtype showed the highest expression rate (48.9%). In univariate and multivariate survival analyses, RET expression had no impact on overall survival.ConclusionWe confirmed the co-expression of RET and ER, but we did not find RET expression to be an independent prognostic factor in human breast cancer. Clinical trials with newly developed RET inhibitors are needed to evaluate if RET inhibition has a beneficial impact on patient survival in ER positive breast cancer.

CCL1 is a major regulatory T cell attracting factor in human breast cancer

BackgroundRegulatory T cells (Treg) suppress cytotoxic T cell anti-tumoral immune responses and thereby promote tumor progression. Prevention of intratumoral Treg accumulation by inhibition of their migration to the tumor microenvironment is a promising therapeutic strategy. The aim of this study was to identify the role of the two major Treg-attracting chemokines CCL1 and CCL22 in human breast cancer.MethodsOne hundred ninety-nine tissue samples of patients with invasive breast cancer were stained for CCL1 and CCL22 by immunohistochemistry. Chemokine expression and tumor infiltration by regulatory T cells, determined by expression of the transcription factor FoxP3, were quantified and their correlation to clinical features was statistically analyzed.ResultsBoth CCL1 and CCL22 were expressed in most breast cancer tissues. CCL1 was significantly over-expressed in invasive breast cancer as compared to normal breast tissue. CCL1, but surprisingly not CCL22, showed a significant correlation with the number of tumor-infiltrating FoxP3+ Treg (p< 0.001). High numbers of intratumoral CCL1 expressing cells were related to high grade tumors (G4) and a positive estrogen receptor (ER) status whereas high CCL22 expression was generally seen in lower grade tumors. The median survival of 88 patients with high intratumoral CCL1 expression was 37 months compared to 50 months for the 87 patients with low CCL1 levels, this trend was however not statistically significant.ConclusionsWe found a high expression of CCL1 in human breast cancer. CCL1 significantly correlated with the infiltration of immunosuppressive FoxP3+ Treg, that are known to negatively affect survival. Thus, CCL1 may serve as prognostic marker and novel therapeutic target in breast cancer.

Mammalian sterile 20-like kinase 1 expression and its prognostic significance in patients with breast cancer.

Mammalian sterile 20-like kinase 1 (Mst1) is a major inhibitor of cell proliferation, and is involved in apoptosis, oncogenesis and organ growth via its ubiquitously encoded serine threonine kinase. Previous studies have demonstrated that Mst1 has a tumor suppressor function in human breast cancer. Mst1 deletion or mutation is associated with tumorigenesis, whereas Mst1 overexpression leads to tumor cell apoptosis and decreases proliferation of tumor cells. Our previous study reported the tumor suppressive function of Mst1, and debated Mst1 as a prognostic factor in human breast cancer. In the present study, Mst1 levels were measured in the plasma of patients in order to elucidate their association with overall and disease-free survival. The results of the present study indicated that Mst1 is a strong prognostic and predictive factor in human breast cancer and a promising anticancer target.

Promoter-level expression clustering identifies time development of transcriptional regulatory cascades initiated by ErbB receptors in breast cancer cells.

The analysis of CAGE (Cap Analysis of Gene Expression) time-course has been proposed by the FANTOM5 Consortium to extend the understanding of the sequence of events facilitating cell state transition at the level of promoter regulation. To identify the most prominent transcriptional regulations induced by growth factors in human breast cancer, we apply here the Complexity Invariant Dynamic Time Warping motif EnRichment (CIDER) analysis approach to the CAGE time-course datasets of MCF-7 cells stimulated by epidermal growth factor (EGF) or heregulin (HRG). We identify a multi-level cascade of regulations rooted by the Serum Response Factor (SRF) transcription factor, connecting the MAPK-mediated transduction of the HRG stimulus to the negative regulation of the MAPK pathway by the members of the DUSP family phosphatases. The finding confirms the known primary role of FOS and FOSL1, members of AP-1 family, in shaping gene expression in response to HRG induction. Moreover, we identify a new potential regulation of DUSP5 and RARA (known to antagonize the transcriptional regulation induced by the estrogen receptors) by the activity of the AP-1 complex, specific to HRG response. The results indicate that a divergence in AP-1 regulation determines cellular changes of breast cancer cells stimulated by ErbB receptors.

Expression of programmed death ligand 1 (PD-L1) is associated with poor prognosis in human breast cancer

Recent studies in multiple epithelial cancers have shown thatthe inhibitory receptor programmed cell death 1 (PD-1) is expressed on tumor-infiltrating lymphocytes and/or programmed death ligand 1 (PD-L1) is expressed on tumor cells, suggesting that antitumor immunity may be modulated by the PD-1/PD-L1 signaling pathway. In addition, phase 1 clinical trials with monoclonal antibodies targeting PD-1 or PD-L1 have shown promising results in several human cancers. The purpose of this study was to investigate the impact of PD-L1 expression in human breast cancer specimens. We conducted an immunohistochemistry study using a tissue microarray encompassing 650 evaluable formalin-fixed breast cancer cases with detailed clinical annotation and outcomes data. PD-L1 was expressed in 152 (23.4%) of the 650 breast cancer specimens. Expression was significantly associated with age, tumor size, AJCC primary tumor classification, tumor grade, lymph node status, absence of ER expression, and high Ki-67 expression. In univariate analysis, PD-L1 expression was associated with a significantly worse OS. In multivariate analysis, PD-L1 expression remained an independent negative prognostic factor for OS. In subset analyses, expression of PD-L1 was associated with significantly worse OS in the luminal B HER2(-) subtype, the luminal B HER2(+) subtype, the HER2 subtype, and the basal-like subtype. This is the first study to demonstrate that PD-L1 expression is an independent negative prognostic factor in human breast cancer. This finding has important implications for the application of antibody therapies targeting the PD-1/PD-L1 signaling pathway in this disease.

TFAP2C governs the luminal epithelial phenotype in mammary development and carcinogenesis.

Molecular subtypes of breast cancer are characterized by distinct patterns of gene expression that are predictive of outcome and response to therapy. The luminal breast cancer subtypes are defined by the expression of ER-alpha (ERα)-associated genes, many of which are directly responsive to the Transcription Factor Activator Protein 2C (TFAP2C). TFAP2C participates in a gene regulatory network controlling cell growth and differentiation during ectodermal development and regulating ESR1/ERα and other luminal cell-associated genes in breast cancer. TFAP2C has been established as a prognostic factor in human breast cancer, however, its role in the establishment and maintenance of the luminal cell phenotype during carcinogenesis and mammary gland development have remained elusive. Herein, we demonstrate a critical role for TFAP2C in maintaining the luminal phenotype in human breast cancer and in influencing the luminal cell phenotype during normal mammary development. Knockdown of TFAP2C in luminal breast carcinoma cells induced EMT with morphological and phenotypic changes characterized by a loss of luminal-associated gene expression and a concomitant gain of basal-associated gene expression. Conditional knockout of the mouse homolog of TFAP2C, Tcfap2c, in mouse mammary epithelium driven by MMTV-Cre promoted aberrant growth of the mammary tree leading to a reduction in the CD24hi/CD49fmid luminal cell population and concomitant gain of the CD24mid/CD49fhi basal cell population at maturity. Our results establish TFAP2C as a key transcriptional regulator for maintaining the luminal phenotype in human breast carcinoma. Furthermore, Tcfap2c influences development of the luminal cell type during mammary development. The data suggest that TFAP2C plays an important role in regulated luminal specific genes and may be a viable therapeutic target in breast cancer.

Prognostic significance of mammalian sterile 20-like kinase 1 in breast cancer

Mammalian sterile 20-like kinase 1 (Mst1) has been proved in the process of apoptosis and tumor suppression. The aim of the study was to investigate the expression of Mst1 in breast cancer and to evaluate its prognostic significance. The expression of Mst1 was examined in 110 breast cancer patients by immunohistochemistry, in which 80 (72.7 %) were defined as positive for Mst1 expression. Patients with negative expression of Mst1 had poor overall survival, comparing with those with positive expression using Kaplan-Meier survival analysis (P = 0.009). Multivariate analysis using Cox proportional hazards model showed that Mst1 expression was a significant independent prognostic factor in breast cancer (P = 0.030). Our results presented the tumor suppressive role of Mst1, and confirmed Mst1 was a prognostic factor in human breast cancer.

Src homology phosphotyrosyl phosphatase‐2 expression is an independent negative prognostic factor in human breast cancer

Src homology phosphotyrosyl phosphatase-2 (SHP2) is a ubiquitously expressed phosphatase that plays an essential role in the downstream signalling pathways of multiple growth factor receptors, thus representing a potential target for cancer therapy. Recent studies suggest that SHP2 contributes to tumour initiation, progression and metastasis in breast cancer, yet the impact of SHP2 expression on prognosis in human breast cancer has not been evaluated. To explore further the role of SHP2 in breast cancer, we conducted an immunohistochemical study using a tissue microarray encompassing 1401 formalin-fixed breast cancer specimens with detailed clinical annotation and outcome data. Of 1401 evaluable breast cancers, 651 (46%) were positive for SHP2. SHP2 expression was associated positively with tumour grade, lymph node status and tumour stage. In univariate survival analysis, cases with SHP2 expression had a significantly worse overall survival (OS). In multivariate analysis, SHP2 remained an independent negative prognostic factor for OS. SHP2 expression was a negative prognostic factor for OS in the luminal A and the luminal B HER2(-) intrinsic subtypes. Our data demonstrate for the first time that SHP2 is an independent predictor of survival in breast cancer, suggesting that SHP2 may be a potential target for therapy.

Abstract A79: Elucidating the role of E2F2 transcription factor in mediating human breast cancer metastasis

Abstract In human breast cancer metastasis, it is not the primary tumor that is the cause of mortality but metastasis to distant sites. Therefore, it is important to elucidate the biological mechanism that underlies the metastatic processes. To address this, we utilized bioinformatic methods in combination with biochemical assays and genetic studies. Specifically, we crossed a MMTV-Myc mouse model with various activator E2Fs mutants and found that the tumor incidence decreased in the MMTV-Myc mice crossed with E2F2 and E2F3 mutant background. Surprisingly, we also found that the loss of E2F2 sharply increased lung metastasis in MMTV-Myc mice. Here, we test whether these observations in mice translate to human breast cancer and identify the genes under the control of E2F2 transcription factor that are responsible for mediating breast cancer metastasis. To achieve these aims, we examined the probability of activation of the E2F2 transcription factors in human breast cancer. We calculated the probability of E2F2 activation and used this data to stratify the human breast cancer samples and their associated metastatic clinical data. We performed hierarchical clustering of human and mouse gene expression datasets and uncovered two clusters of human breast tumors in which E2F2 played distinctly different roles in mediating metastasis. The human breast cancer samples that clustered with our mouse gene expression data exhibited the same role for E2F2 whereby it increased time to distant metastasis. We then examined genes that were differentially regulated within this cluster and found that there was a set of genes that were associated with a difference in human metastasis survival times and with the E2F2 knockout in the mouse model. To further explore the mechanism by which E2F2 mediates human breast cancer metastasis, we have identified four genes asputative E2F2 target genes including KLK1, MYH2, PTPRD and TNNC2. We found that partial knockdown of KLK1 promotes the migratory capacity of MCF7 cell in vitro. In addition, partial knockdown of PTPRD affected cellular morphology, where they were found to grow in discreet clusters while having little effect on the migration capacity in a scratch assay. We are currently exploring the effects of MYH2 and TNNC2 ablation on these cells. Taken together, we have begun to elucidate the roles of E2F2 transcription factor in mediating breast cancer metastasis as well as establishing a mechanism by which E2F2 regulates metastasis. Citation Format: Inez Yuwanita, Danielle Barnes, Eran Andrechek. Elucidating the role of E2F2 transcription factor in mediating human breast cancer metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr A79.

Nuclear Expression of Snail Is an Independent Negative Prognostic Factor in Human Breast Cancer

Background. Snail is a key regulator of epithelial-mesenchymal transition of tumor cells. Several studies have shown nuclear Snail expression to be a negative prognostic factor in human cancer, where it is generally associated with more aggressive tumor behavior and worse survival. Objectives and Methods. To further explore the role of Snail expression in breast cancer, we conducted a study on a tissue microarray, encompassing 1043 breast cancer cases. Results. A total of 265 (25.4%) breast cancers were positive for Snail. Snail expression was significantly associated with greater tumor size, higher tumor stage and grade, positive lymph node status, and hormone receptor negative status and was differently expressed in the intrinsic subtypes of breast cancer, being the highest in the basal-like subtype and the lowest in the luminal A subtype. In multivariate analysis, Snail proved to be an independent negative prognostic factor for OS. In the intrinsic subtypes, Snail expression was a negative prognostic factor for OS in the luminal B HER2−, the luminal B HER2+, and the basal-like subtype. Conclusions. This is the first study demonstrating that nuclear Snail expression is an independent negative predictor of prognosis in breast cancer, thus suggesting that it may represent a potential therapeutic target.

PTP1B expression is an independent positive prognostic factor in human breast cancer

Protein tyrosine phosphatase 1B (PTP1B) is a non-transmembrane protein tyrosine phosphatase that has come into focus as a critical regulator of multiple signaling pathways. The role of PTP1B in breast cancer remains unclear with evidence suggesting that PTP1B can exert both tumor-suppressing and tumor-promoting effects. To better define the role of PTP1B in human breast cancer, and its relationship with HER2, we performed immunohistochemical studies on a large cohort of functionally annotated primary breast cancer specimens. 683 of 1,402 (49 %) evaluable primary breast cancers are positive for PTP1B. There is no statistically significant association between PTP1B expression and age, tumor size, T stage, histologic grade, lymph node status, or histological subtype. Of note, there is no significant association between PTP1B expression and HER2 expression (PTP1B expression 53.1 % in HER2(+) cancers vs. 47.5 % in HER2(-) cancers, p = 0.0985). However, PTP1B expression is significantly associated with estrogen receptor expression (PTP1B expression 50.7 % in ER(+) cancers vs. 43.1 % in ER(-) cancers, p = 0.0137) and intrinsic molecular subtype (PTP1B expression 53.9 % in the luminal B HER2(+) subtype and 37.9 % in the basal-like subtype). Of note, multivariate analyses demonstrate that PTP1B is an independent predictor of improved survival in breast cancer (HR 0.779, p = 0.006). Taken together, we demonstrate in the largest study to date that (1) PTP1B is commonly expressed in breast cancer, (2) there is no association or functional impact of PTP1B expression in HER2(+) breast cancer, and (3) PTP1B expression in breast cancer is associated with significantly improved clinical outcome. Until additional studies are performed, caution should be exercised in using PTP1B inhibitors in human breast cancer.

Abstract 2596: Correlation of TGF beta receptor II and pSmad2 expression with clinico-pathological factors in human breast cancer: An immunohistochemical observation from the Shanghai Breast Cancer Study

Abstract Loss of transforming growth factor (TGF)-α expression occurs in the early stages of breast carcinogenesis, which contributes to tumor progression. The loss of TGF-β responsiveness frequently occurs at the level of the TGF- ≤ receptor II (TGF-βRII) in breast cancer. Smad2 is a major receptor-activated Smad downstream of TGF-β signaling. Phosphorylated Smad2 (pSmad2) is translocated into the nucleus to modulate transcription of target genes involved in many cell functions. We evaluated the correlation of TGF-βRII and pSmad2 protein expression with clinico-pathological factors in human breast cancer tissue from 435 breast cancer cases from the Shanghai Breast Cancer Study, a population-based, case-control study. Expression of the TGF-βRII and pSmad2 proteins was detected using a double immunofluorescence staining method, which was validated with standard single immunostains. Lab-constructed tissue microarray samples were used as positive and negative controls. The immunofluorescence signals were designated as negative, positive, or strong-positive based on a modified Allred scoring system. Staining patterns of TGF-βRII were classified into membranous or cytoplasmic predominant. TGF-βRII expression intensity was significantly higher in normal and early-stage breast cancers (in situ carcinoma) than that in later stages (in situ carcinoma adjacent to invasive carcinoma, and invasive carcinoma) (P&amp;lt;0.001). The cytoplasmic predominant expression pattern of TGF-βRII was more frequently observed in breast cancer than that in normal breast epithelium on the same tissue section (P&amp;lt;0.001). pSmad2 expression was significantly increased in breast cancer compared with adjacent normal breast epithelium. In addition, the increased pSmad2 expression was significantly associated with higher breast cancer grade (P=0.004). No significant correlations between TGF-βRII/pSmad2 protein expression and other prognostic factors, such as age at diagnosis, menopause status, history of breast cancer, TNM stage, and ER/PR/HER2 status, was found. The results of this study suggest that reduced TGF-βRII expression and its cytoplasmic predominant expression pattern may be associated with the progression of breast cancer, and increased pSmad2 expression may be associated with carcinogenesis and poor differentiation of breast cancer cells. Additional samples are being analyzed to validate these findings and to evaluate the expression of TGF-βRII and pSmad2 in relation to breast cancer survival. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2596. doi:1538-7445.AM2012-2596

Abstract 1286: Elucidating the role of E2F2 in mediating human breast cancer metastasis

Abstract In human breast cancer it is not the primary tumor that is the cause of mortality but tumor metastasis to distant sites. Therefore, it is important to elucidate the biological mechanisms that underlie the metastatic processes. To address this, we utilized bioinformatic methods in combination with biochemical assays and genetic studies. Specifically, we crossed MMTV-Myc transgenic mice with various activator E2Fs mutants. We found that the tumor incidence decreased in MMTV-Myc mice interbred with E2F2 and E2F3 mutant backgrounds. Surprisingly, we also found that the loss of E2F2 sharply increased the percentage of lung metastasis in MMTV-Myc mice. Here, we test whether these observations in mice translate to human breast cancer and identify the genes under the control of E2F2 transcription factor that are responsible for mediating breast cancer metastasis. To achieve these aims, we examined the probability of activation of the E2F2 transcription factors in human breast cancer. We calculated the probability of E2F2 activation and used this data to stratify the human breast cancer samples and their associated metastatic clinical data. Examining this data we found that a low probability of E2F2 pathway activation led to decreased time to distant metastasis. To account for this discrepancy, we performed hierarchical clustering of human and mouse gene expression datasets. We found two clusters of human breast tumors in which E2F2 played distinctly different roles in mediating metastasis. One particular cluster clustered with our mouse gene expression data and exhibited the same role for E2F2 where it increased time to distant metastasis. In addition, we examined the ontology of the genes in this cluster and found that the majority of these genes had putative E2F binding sites. To further identify genes that are involved in metastasis, we stratified human breast cancer metastasis clinical annotation using gene expression values from these genes. We found that there were seven genes that are uniquely differentially regulated in this cluster. Interestingly, we observed that this group of seven genes included genes that were implicated in the metastatic process such as MMP16. Taken together, our results showed that there is an important role for E2F2 in mediating breast cancer metastasis and using our bioinformatic methods, we have begun to elucidate this role of E2F2 in mediating breast cancer metastasis. Our future directions include further validation of these target genes in vitro and in vivo to establish the mechanism by which E2F2 mediates breast cancer metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1286. doi:1538-7445.AM2012-1286

Nucleobindin 2 in human breast carcinoma as a potent prognostic factor.

It is well-known that estrogens immensely contribute to the progression of human breast carcinoma, but their detailed molecular mechanisms remain largely unclear. In this study, we identified nucleobindin 2 (NUCB2) as a gene associated with recurrence based on microarray data of estrogen receptor (ER)-positive breast carcinoma cases (n = 10), and subsequent in vitro study showed that NUCB2 expression was upregulated by estradiol in ER-positive MCF-7 cells. However, NUCB2 has not yet been examined in breast carcinoma, and its significance remains unknown. Therefore, we further examined the biological functions of NUCB2 in breast carcinoma using immunohistochemistry and in vitro studies. NUCB2 immunoreactivity was detected in carcinoma cells in 77 of 161 (48%) breast cancer cases, and positively associated with lymph node metastasis and ER status of the patients. In addition, NUCB2 status was significantly associated with an increased risk of recurrence and adverse clinical outcome of the patients using both univariate and multivariate analyses. Results of siRNA transfection experiments showed that NUCB2 significantly increased cell proliferation, and migration and invasion properties in both MCF-7 and ER-negative SK-BR-3 cells. These results suggest that NUCB2 is upregulated by estrogens and plays an important role, especially in the process of metastasis, in breast carcinomas. NUCB2 status is considered a potent prognostic factor in human breast cancer.

New Therapeutic Approach and Prognostic Factors in Human Breast Cancer

New Therapeutic Approach and Prognostic Factors in Human Breast Cancer