Neuroblastoma Arising in an Immature Teratoma of the Ovary in a 13-Year-Old.

Somatic malignancies arising in mature teratomas are exceedingly rare entities and even more so are those arising in immature teratomas. Here, we present a unique case of a 13-year-old who initially underwent ovarian sparing cystectomy for a 7.7 cm left ovarian mass with a pre-operative diagnosis of mature cystic teratoma. Histologically, all 3 germ cell layers were present and immature neuroepithelial tubules were also identified. Subsequent sections revealed a nodular lesion composed of neuropil, neuroblasts with a spectrum of maturation, and Schwannian-type stroma. The neuroblasts were diffusely positive for PHOX2B. Neuroblastoma arising in an immature teratoma has only been described in the literature once previously in an adult patient.

Increased Otoferlin Expression in B Cells Is Associated with Muscle Weakness in Untreated Juvenile Dermatomyositis: A Pilot Study.

Otoferlin mRNA expression is increased in JDM patients' PBMCs and muscle compared to healthy controls. This study aims to evaluate the role of otoferlin in JDM disease pathophysiology and its association with disease activity in untreated children with JDM. A total of 26 untreated JDM (88.5% female, 92.3% white, non-Hispanic) and 15 healthy controls were included in this study. Otoferlin mRNA expression was determined by qRT-PCR before and a few months after therapy. Detailed flow cytometry of various cell surface markers and cytoplasmic otoferlin was performed to identify cells expressing otoferlin. In addition, muscle otoferlin expression was evaluated in situ in six untreated JDM patients and three healthy controls. There was a significant increase in otoferlin expression in JDM children compared to controls (Median 67.5 vs. 2.1; p = 0.001). There was a positive correlation between mRNA otoferlin expression and the following disease activity markers: disease activity scores (DAS)-total (rs = 0.62, p < 0.001); childhood myositis assessment scale (CMAS) (rs = -0.61, p = 0.002); neopterin (rs = 0.57, p = 0.004) and von Willebrand factor antigen (vWF: Ag) (rs = 0.60, p = 0.004). Most of the otoferlin-positive cells were unswitched B cells (63-99.4%), with 65-75% of them expressing plasmablast markers (CD19+, IgM+, CD38hi, CD24-). The findings of this pilot study suggest that otoferlin expression is associated with muscle weakness, making it a possible biomarker of disease activity. Additionally, B cells and plasmablasts were the primary cells expressing otoferlin.

ß-catenin regulates c-Myc and CDKN1A expression in breast cancer cells.

We previously reported that the Wnt pathway is preferentially activated in basal-like breast cancer. However, the mechanisms by which the Wnt pathway regulates down-stream targets in basal-like breast cancer, and the biological significance of this regulation, are poorly understood. In this study, we found that c-Myc is highly expressed in the basal-like subtype by microarray analyses and immunohistochemical staining. After silencing ß-catenin using siRNA, c-Myc expression was decreased in non-basal-like breast cancer cells. In contrast, c-Myc mRNA and protein expression were up-regulated in the basal-like breast cancer cell lines. Decreased c-Myc promoter activity was observed after inhibiting ß-catenin by siRNA in non-basal-like breast cancer cells; however, inhibition of ß-catenin or over-expression of dominant-negative LEF1 had no effect on c-Myc promoter activity in basal-like breast cancer cell lines. In addition, CDKN1A mRNA and p21 protein expression were significantly increased in all breast cancer cell lines upon ß-catenin silencing. Interestingly, inhibiting ß-catenin expression alone did not induce apoptosis in breast cancer cell lines despite c-Myc regulation, but we observed a modest increase of cells in the G1 phase of the cell cycle and decrease of cells in S phase upon ß-catenin silencing. Our findings suggest that the regulation of c-Myc in breast cancer cells is dependent on the molecular subtype, and that ß-catenin-mediated regulation of c-Myc and p21 may control the balance of cell death and proliferation in breast cancer.

Expression and sub-cellular localization of an epigenetic regulator, co-activator arginine methyltransferase 1 (CARM1), is associated with specific breast cancer subtypes and ethnicity.

BACKGROUND: Co-Activator Arginine Methyltransferase 1(CARM1) is an Estrogen Receptor (ER) cofactor that remodels chromatin for gene regulation via methylation of Histone3. We investigated CARM1 levels and localization across breast cancer tumors in a cohort of patients of either European or African ancestry. METHODS: We analyzed CARM1 levels using tissue microarrays with over 800 histological samples from 549 female cancer patients from the US and Nigeria, Africa. We assessed associations between CARM1 expression localized to the nucleus and cytoplasm for 11 distinct variables, including; ER status, Progesterone Receptor status, molecular subtypes, ethnicity, HER2+ status, other clinical variables and survival. RESULTS: We found that levels of cytoplasmic CARM1 are distinct among tumor sub-types and increased levels are associated with ER-negative (ER-) status. Higher nuclear CARM1 levels are associated with HER2 receptor status. EGFR expression also correlates with localization of CARM1 into the cytoplasm. This suggests there are distinct functions of CARM1 among molecular tumor types. Our data reveals a basal-like subtype association with CARM1, possibly due to expression of Epidermal Growth Factor Receptor (EGFR). Lastly, increased cytoplasmic CARM1, relative to nuclear levels, appear to be associated with self-identified African ethnicity and this result is being further investigated using quantified genetic ancestry measures. CONCLUSIONS: Although it is known to be an ER cofactor in breast cancer, CARM1 expression levels are independent of ER. CARM1 has distinct functions among molecular subtypes, as is indicative of its sub-cellular localization and it may function in subtype etiology. These sub-cellular localization patterns, indicate a novel role beyond its ER cofactor function in breast cancer. Differential localization among ethnic groups may be due to ancestry-specific polymorphisms which alter the gene product.

Use of Web-based training for quality improvement between a field immunohistochemistry laboratory in Nigeria and its United States-based partner institution.

The importance of hormone receptor status in assigning treatment and the potential use of human epidermal growth factor receptor 2 (HER2)-targeted therapy have made it beneficial for laboratories to improve detection techniques. Because interlaboratory variability in immunohistochemistry (IHC) tests may also affect studies of breast cancer subtypes in different countries, we undertook a Web-based quality improvement training and a comparative study of accuracy of immunohistochemical tests of breast cancer biomarkers between a well-established laboratory in the United States (University of Chicago) and a field laboratory in Ibadan, Nigeria. Two hundred and thirty-two breast tumor blocks were evaluated for estrogen receptors (ERs), progesterone receptors (PRs), and HER2 status at both laboratories using tissue microarray technique. Initially, concordance analysis revealed κ scores of 0.42 (moderate agreement) for ER, 0.41 (moderate agreement) for PR, and 0.39 (fair agreement) for HER2 between the 2 laboratories. Antigen retrieval techniques and scoring methods were identified as important reasons for discrepancy. Web-based conferences using Web conferencing tools such as Skype and WebEx were then held periodically to discuss IHC staining protocols and standard scoring systems and to resolve discrepant cases. After quality assurance and training, the agreement improved to 0.64 (substantial agreement) for ER, 0.60 (moderate agreement) for PR, and 0.75 (substantial agreement) for HER2. We found Web-based conferences and digital microscopy useful and cost-effective tools for quality assurance of IHC, consultation, and collaboration between distant laboratories. Quality improvement exercises in testing of tumor biomarkers will reduce misclassification in epidemiologic studies of breast cancer subtypes and provide much needed capacity building in resource-poor countries.

Proliferating macrophages associated with high grade, hormone receptor negative breast cancer and poor clinical outcome.

Macrophages, a key cell in the inflammatory cascade, have been associated with poor prognosis in cancers, including breast cancer. In this study, we investigated the relationship of a subset of macrophages-proliferating macrophages (promacs)-with clinico-pathologic characteristics of breast cancer, including tumor size, grade, stage, lymph node metastases, hormone receptor status, subtype, as well as early recurrence, and survival. This study included a discovery and validation set that was conducted at two institutions and laboratories (University of California, San Francisco and University of Chicago) using two independent cohorts of patients with breast cancer. Formalin-fixed, paraffin-embedded sections and/or tissue microarrays were double-stained with anti-CD68 (a macrophage marker) and anti-PCNA (a proliferation marker) antibodies. The presence of intratumoral promacs was significantly correlated with high grade, hormone receptor negative tumors, and a basal-like subtype. In contrast, there was no correlation between promacs and tumor size, stage, or the number of the involved lymph nodes. These findings were consistent between the two study cohorts. Finally, promac numbers were a significant predictor of recurrence and survival. In the pooled analysis, elevated promac levels were associated with a 77% increased risk of dying (P = 0.015). The presence of promacs in human breast cancer may serve as a prognostic indicator for poor outcomes and early recurrence and serve as a potential cellular target for novel therapeutic interventions.

Wnt/beta-catenin pathway activation is enriched in basal-like breast cancers and predicts poor outcome.

Although Wnt/beta-catenin pathway activation has been implicated in mouse models of breast cancer, there is contradictory evidence regarding its importance in human breast cancer. In this study, invasive and in situ breast cancer tissue microarrays containing luminal A, luminal B, human epidermal growth factor receptor 2 (HER2)(+)/ER(-) and basal-like breast cancers were analyzed for beta-catenin subcellular localization. We demonstrate that nuclear and cytosolic accumulation of beta-catenin, a read-out of Wnt pathway activation, was enriched in basal-like breast cancers. In contrast, membrane-associated beta-catenin was observed in all breast cancer subtypes, and its expression decreased with tumor progression. Moreover, nuclear and cytosolic localization of beta-catenin was associated with other markers of the basal-like phenotype, including nuclear hormone receptor and HER2 negativity, cytokeratin 5/6 and vimentin expression, and stem cell enrichment. Importantly, this subcellular localization of beta-catenin was associated with a poor outcome and is more frequently observed in tumors from black patients. In addition, beta-catenin accumulation was more often observed in basal-like in situ carcinomas than other in situ subtypes, suggesting that activation of this pathway might be an early event in basal-like tumor development. Collectively, these data indicate that Wnt/beta-catenin activation is an important feature of basal-like breast cancers and is predictive of worse overall survival, suggesting that it may be an attractive pharmacological target for this aggressive breast cancer subtype.

Genomic analysis of estrogen cascade reveals histone variant H2A.Z associated with breast cancer progression.

We demonstrate an integrated approach to the study of a transcriptional regulatory cascade involved in the progression of breast cancer and we identify a protein associated with disease progression. Using chromatin immunoprecipitation and genome tiling arrays, whole genome mapping of transcription factor-binding sites was combined with gene expression profiling to identify genes involved in the proliferative response to estrogen (E2). Using RNA interference, selected ERalpha and c-MYC gene targets were knocked down to identify mediators of E2-stimulated cell proliferation. Tissue microarray screening revealed that high expression of an epigenetic factor, the E2-inducible histone variant H2A.Z, is significantly associated with lymph node metastasis and decreased breast cancer survival. Detection of H2A.Z levels independently increased the prognostic power of biomarkers currently in clinical use. This integrated approach has accelerated the identification of a molecule linked to breast cancer progression, has implications for diagnostic and therapeutic interventions, and can be applied to a wide range of cancers.

A selective small molecule inhibitor of c-Met, PHA665752, inhibits tumorigenicity and angiogenesis in mouse lung cancer xenografts.

The c-Met receptor tyrosine kinase is emerging as a novel target in many solid tumors, including lung cancer. PHA-665752 was identified as a small molecule, ATP competitive inhibitor of the catalytic activity of the c-Met kinase. Here, we show that treatment with PHA665752 reduced NCI-H69 (small cell lung cancer) and NCI-H441 (non-small cell lung cancer) tumorigenicity in mouse xenografts by 99% and 75%, respectively. Reduction in tumor size was also observed by magnetic resonance imaging of tumors in mice. PHA665752 inhibited c-Met phosphorylation at the autophosphorylation and c-Cbl binding sites in mouse xenografts derived from non-small cell lung cancer cell lines (NCI-H441 and A549) and small cell lung cancer cell line (NCI-H69). PHA665752 also inhibited angiogenesis by >85% in all the abovementioned cell lines and caused an angiogenic switch which resulted in a decreased production of vascular endothelial growth factor and an increase in the production of the angiogenesis inhibitor thrombospondin-1. These studies show the feasibility of selectively targeting c-Met with ATP competitive small molecule inhibitors and suggest that PHA665752 may provide a novel therapeutic approach to lung cancer.

Tamoxifen overrides autophagy inhibition in Beclin-1-deficient glioma cells and their resistance to adenovirus-mediated oncolysis via upregulation of PUMA and BAX.

Autophagy is an evolutionarily conserved process regulating cellular homeostasis via digestion of dysfunctional proteins and whole cellular organelles by mechanisms, involving their enclosure into double-membrane vacuoles that are subsequently fused to lysosomes. Glioma stem cells utilize autophagy as a main mechanism of cell survival and stress response. Most recently, we and others demonstrated induction of autophagy in gliomas in response to treatment with chemical drugs, such as temozolomide (TMZ) or oncolytic adenoviruses (Ads). As autophagy has been implicated in the mechanism of Ad-mediated cell killing, autophagy deficiency in some glioma tumors could be the reason for their resistance to oncolysis. Despite the observed connection, the exact relationship between autophagy-activating cell signaling and adenoviral infection remains unclear. Here, we report that inhibition of autophagy in target glioma cells induces their resistance to killing by oncolytic agent CRAd-S-5/3. Furthermore, we found that downregulation of autophagy inducer Beclin-1 inhibits replication-competent Ad-induced oncolysis of human glioma by suppressing cell proliferation and inducing premature senescence. To overcome the autophagy-deficient state of such glioma cells and restore their susceptibility to oncolytic Ad infection, we propose treating glioma tumors with an anticancer drug tamoxifen (TAM) as a means to induce apoptosis in Ad-targeted cancer cells via upregulation of BAX/PUMA genes. In agreement with the above hypothesis, our data suggest that TAM improves susceptibility of Beclin-1-deficient glioma cells to CRAd-S-5/3 oncolysis by means of activating autophagy and pro-apoptotic signaling pathways in the target cancer cells.

Survivin-driven and fiber-modified oncolytic adenovirus exhibits potent antitumor activity in established intracranial glioma.

The poor prognosis of patients with malignant gliomas necessitates the development of novel therapies. Virotherapy, using genetically engineered adenovectors that selectively replicate in and kill neoplastic cells, represents one such strategy. In this study, we examined several oncolytic vectors with modified transcriptional and transductional control of viral replication. First, we incorporated the survivin promoter (S) to drive E1A gene expression. We then modified the adenovirus serotype 5 (Ad5) fiber protein via genetic knob switching or incorporation of peptide ligands to target the following glioma-associated receptors: the Ad3 attachment protein, or CD46, alpha(v) beta(3)/alpha(v)beta(5) integrins, or heparan sulfate proteoglycans. The three conditionally replicative adenoviruses, CRAd-S-5/3, CRAd-S-RGD, and CRAd-S-pk7, were then examined in vitro with respect to transduction efficiency and tissue specificity. The most promising virus was then tested in vivo for evidence of tumor growth inhibition. CRAd-S-pk7 provided the highest level of viral replication and tumor oncolysis in glioma cell lines. At the same time, we observed minimal viral replication and toxicity in normal human brain. Injection of CRAd-S-pk7 inhibited xenograft tumor growth by more than 300% (p < 0.001). Sixty-seven percent of treated mice with intracranial tumors were long-term survivors (>110 days; p < 0.005). Analysis of tumor tissue indicated increased adenoviral infectivity, decreased mitotic activity, and enhanced tumor apoptosis. These findings demonstrate the effectiveness of CRAd-S-pk7 and provide the rationale for further development of this novel oncolytic virus for glioma gene therapy.

Enhanced transduction of malignant glioma with a double targeted Ad5/3-RGD fiber-modified adenovirus.

Malignant brain tumors remain refractory to adenovirus type 5 (Ad5)-based gene therapy, mostly due to the lack of the primary Ad5 receptor, the coxsackie and adenovirus receptor, on brain tumor cells. To bypass the dependence on coxsackie and adenovirus receptor for adenoviral entry and infectivity, we used a novel, double targeted Ad5 backbone-based vector carrying a chimeric Ad5/3 fiber with integrin-binding RGD motif incorporated in its Ad3 knob domain. We then tested the new virus in vitro and in vivo in the setting of malignant glioma. Ad5/3-RGD showed a 10-fold increase in gene expression in passaged cell lines and up to 75-fold increase in primary tumors obtained from patients relative to the control. These results were further corroborated in our in vivo human glioma xenograft model, where the Ad5/3-RGD vector showed a 1,000-fold increase in infectivity as compared with the control. Taken together, our findings indicate that Ad5/3-RGD may be a superior vector for applications in glioma gene therapy and therefore warrants further attention in the field of neuro-oncology.

Prognostic significance of E-cadherin protein expression in pathological stage I-III endometrial cancer.

PURPOSE: Decreased expression of E-cadherin in endometrial cancer cells is associated with adverse prognostic features. This study aimed to evaluate the prognostic significance of decreased E-cadherin expression in patients with endometrial cancer. EXPERIMENTAL DESIGN: Between 1992 and 1999, 102 endometrial cancer patients with stage I-III disease underwent primary surgery at the University of Chicago. Representative tissue specimens were immunostained with a monoclonal antibody to E-cadherin. A semiquantitative evaluation scale was developed based on the percentage of endometrial cancer cells with membranous E-cadherin staining. Tissue sections were scored as "3" if >75%, "2" if 25-75%, "1" if 5-25%, and "0" if <5% of cells stained. E-Cadherin staining was correlated with overall survival (OS), cause-specific survival (CSS), progression-free survival (PFS), and extrapelvic progression. Multivariate Cox proportional hazards modeling was used to estimate hazard ratios, controlling for clinicopathological characteristics and adjuvant treatment. Median follow-up for the study group was 58.5 months. RESULTS: E-Cadherin staining was scored as 0, 1, 2, and 3 in 29.4%, 18.6%, 26.5%, 25.5% of cases, respectively. E-Cadherin expression was positively correlated with myometrial invasion (Kendall tau: 0.30, P < 0.01), and negatively correlated with grade (Kendall tau: -0.13, P = 0.15) and papillary serous or clear cell histology (Kendall tau: -0.14, P = 0.12). Five-year actuarial OS, CSS, PFS, and extrapelvic recurrence rates for negative (score = 0), heterogeneous (score = 1-2), and positive (score = 3) staining were as follows: OS, 69.2 versus 75.7 versus 81.0% (P = 0.64); CSS, 78.8 versus 91.2 versus 95.5% (P = 0.19); PFS, 69.1 versus 88.6 versus 92.2% (P = 0.079), and extrapelvic progression, 20.8 versus 7.3 versus 4.0% (P = 0.17). On multivariate Cox regression, a higher E-cadherin expression score was associated with decreased overall mortality [hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.34-1.03; P = 0.066), and statistically significant decreases in endometrial cancer mortality (HR, 0.23; 95% CI, 0.055-0.94; P = 0.040), disease progression (HR, 0.28; 95% CI, 0.10-0.77; P = 0.014), and extrapelvic recurrence (HR, 0.24; 95% CI, 0.062-0.97; P = 0.045). CONCLUSIONS: Decreased E-cadherin expression is an independent prognostic factor for disease progression and mortality in pathological stage I-III endometrial cancer. Evaluation of E-cadherin expression may aid in the selection of patients for more aggressive adjuvant therapy.

Endothelial-like properties of claudin-low breast cancer cells promote tumor vascular permeability and metastasis.

The vasculature serves as the main conduit for breast tumor metastases and is a target of therapeutics in many tumor types. In this study, we aimed to determine if tumor-associated vascular properties could help to explain the differences observed in metastagenicity across the intrinsic subtypes of human breast tumors. Analysis of gene expression signatures from more than 3,000 human breast tumors found that genomic programs that measured vascular quantity, vascular proliferation, and a VEGF/Hypoxia-signature were the most highly expressed in claudin-low and basal-like tumors. The majority of the vascular gene signatures added metastasis-predictive information to immunohistochemistry-defined microvessel density scores and genomically defined-intrinsic subtype classification. Interestingly, pure claudin-low cell lines, and subsets of claudin-low-like cells within established basal-like cancer cell lines, exhibited endothelial/tube-like morphology when cultured on Matrigel. In vivo xenografts found that claudin-low tumors, but not luminal tumors, extensively perfused injected contrast agent through paracellular spaces and non-vascular tumor-lined channels. Taken together, the endothelial-like characteristics of the cancer cells, combined with both the amount and the physiologic state of the vasculature contribute to breast cancer metastatic progression. We hypothesize that the genetic signatures we have identified highlight patients that should respond most favorably to anti-vascular agents.

Expression of polycomb targets predicts breast cancer prognosis.

Global changes in the epigenome are increasingly being appreciated as key events in cancer progression. The pathogenic role of enhancer of zeste homolog 2 (EZH2) has been connected to its histone 3 lysine 27 (H3K27) methyltransferase activity and gene repression; however, little is known about relationship of changes in expression of EZH2 target genes to cancer characteristics and patient prognosis. Here we show that through expression analysis of genomic regions with H3K27 trimethylation (H3K27me3) and EZH2 binding, breast cancer patients can be stratified into good and poor prognostic groups independent of known cancer gene signatures. The EZH2-bound regions were downregulated in tumors characterized by aggressive behavior, high expression of cell cycle genes, and low expression of developmental and cell adhesion genes. Depletion of EZH2 in breast cancer cells significantly increased expression of the top altered genes, decreased proliferation, and improved cell adhesion, indicating a critical role played by EZH2 in determining the cancer phenotype.

Molecular analysis of colorectal tumors within a diverse patient cohort at a single institution.

PURPOSE: African American colorectal cancer patients have worse survival outcomes than Caucasian patients. To determine whether differences exist in the molecular mechanisms driving colorectal cancer between African Americans and Caucasians, we characterized patient tumors from a single institution by assessing genetic alterations involved in colorectal cancer progression and response to treatment. EXPERIMENTAL DESIGN: We retrospectively examined 448 African Americans and Caucasians diagnosed with colorectal cancer at The University of Chicago Medical Center between 1992 and 2002. Microsatellite instability (MSI) status was determined by genotyping the BAT25, BAT26, BAT40, D5S346, and BAX loci. Mutations in KRAS codons 12 and 13 and BRAF codon 600 were identified by direct sequencing. MSI and detected mutations were correlated with clinicopathologic features. RESULTS: Overall, no difference existed in MSI or BRAF mutation frequencies between African Americans and Caucasians. However, African Americans with microsatellite stable (MSS)/MSI-low (MSI-L) tumors had a higher proportion of KRAS mutations than Caucasians (34% vs. 23%, P = 0.048) that was isolated to proximal colon cancers and primarily driven by mutations in codon 13. There was no racial difference in receipt of chemotherapy, but African Americans with MSS/MSI-L tumors had a 73% increased risk of death over Caucasians that could not be explained by known prognostic factors. CONCLUSIONS: The significantly higher risk of death among African Americans with MSS/MSI-L tumors may be related to differences in the distribution of factors influencing response to standard therapies. These data underscore the need for further research into the molecular mechanisms driving colorectal cancer progression in underserved and understudied populations.

Concordance in histological and biological parameters between first and second primary breast cancers.

BACKGROUND: Women with breast cancer are more likely to have a second breast cancer than women in the general population are to have a primary cancer. However, the biological relationship between primary and second breast cancers is not clear. METHODS: A total of 30,617 patients diagnosed with bilateral breast cancers between 1990 and 2007 were identified through 17 cancer registries of the Surveillance, Epidemiology, and End Results program. Logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) was used to model strength of association in hormone receptor status, grade, and histology between 2 cancers. RESULTS: There was a strong association in estrogen receptor status between 2 bilateral tumors (OR, 7.64; 95% CI, 7.00-8.35). The strength of association in estrogen receptor status depended on the time interval between the first and second tumors and age at diagnosis. The OR was 25.9 for synchronous tumors (within 1 month) and 3.69 for metachronous tumors separated by ≥10 years. The strength of association was stronger in patients whose first cancer was diagnosed before age 50 (OR, 11.7) versus after age 50 (OR, 5.71). A similar pattern was observed for progesterone receptor, grade, and histological type, but with relatively weaker association. CONCLUSIONS: The strong concordance in hormone receptor status of primary and second breast cancers suggests that 2 breast cancers arise in a common milieu and that tumor subtypes are predetermined in the early stage of breast carcinogenesis.

Apc mutation enhances PyMT-induced mammary tumorigenesis.

The Adenomatous Polyposis Coli (APC) tumor suppressor gene is silenced by hypermethylation or mutated in up to 70% of human breast cancers. In mouse models, Apc mutation disrupts normal mammary development and predisposes to mammary tumor formation; however, the cooperation between APC and other mutations in breast tumorigenesis has not been studied. To test the hypothesis that loss of one copy of APC promotes oncogene-mediated mammary tumorigenesis, Apc(Min/+) mice were crossed with the mouse mammary tumor virus (MMTV)-Polyoma virus middle T antigen (PyMT) or MMTV-c-Neu transgenic mice. In the PyMT tumor model, the Apc(Min/+) mutation significantly decreased survival and tumor latency, promoted a squamous adenocarcinoma phenotype, and enhanced tumor cell proliferation. In tumor-derived cell lines, the proliferative advantage was a result of increased FAK, Src and JNK signaling. These effects were specific to the PyMT model, as no changes were observed in MMTV-c-Neu mice carrying the Apc(Min/+) mutation. Our data indicate that heterozygosity of Apc enhances tumor development in an oncogene-specific manner, providing evidence that APC-dependent pathways may be valuable therapeutic targets in breast cancer. Moreover, these preclinical model systems offer a platform for dissection of the molecular mechanisms by which APC mutation enhances breast carcinogenesis, such as altered FAK/Src/JNK signaling.

Population differences in breast cancer: survey in indigenous African women reveals over-representation of triple-negative breast cancer.

PURPOSE: Compared with white women, black women experience a disproportionate burden of aggressive breast cancer for reasons that remain unknown and understudied. In the first study of its kind, we determined the distribution of molecular subtypes of invasive breast tumors in indigenous black women in West Africa. PATIENTS AND METHODS: The study comprised 507 patients diagnosed with breast cancer between 1996 and 2007 at six geographic regions in Nigeria and Senegal. Formalin-fixed and paraffin-embedded sections were constructed into tissue microarrays and immunostained with 15 antibodies. Five molecular subtypes were determined, and hierarchical cluster analysis was conducted to explore subgroups for unclassified cases. RESULTS: The mean (+/- standard deviation) age of 378 patients in the first cohort was 44.8 +/- 11.8 years, with the majority of women presenting with large (4.4 +/- 2.0 cm) high-grade tumors (83%) in advanced stages (72% node positive). The proportions of estrogen receptor (ER) -positive, progesterone receptor-positive, and human epidermal growth factor receptor 2 (HER2) -positive tumors were 24%, 20%, and 17%, respectively. Triple negativity for these markers was predominant, including basal-like (27%) and unclassified subtype (28%). Other subtypes were luminal A (27%), luminal B (2%), and HER2 positive/ER negative (15%). The findings were replicated in the second cohort of 129 patients. The unclassified cases could be grouped into a bad prognosis branch, with expression of vascular endothelial growth factor, B-cell lymphoma extra-large protein, and Cyclin E, and a good prognosis branch, with expression of B-cell lymphoma protein 2 and Cyclin D1. CONCLUSION: These findings underscore the urgent need for research into the etiology and treatment of the aggressive molecular subtypes that disproportionately affect young women in the African diaspora.

Identification of conserved gene expression features between murine mammary carcinoma models and human breast tumors.

BACKGROUND: Although numerous mouse models of breast carcinomas have been developed, we do not know the extent to which any faithfully represent clinically significant human phenotypes. To address this need, we characterized mammary tumor gene expression profiles from 13 different murine models using DNA microarrays and compared the resulting data to those from human breast tumors. RESULTS: Unsupervised hierarchical clustering analysis showed that six models (TgWAP-Myc, TgMMTV-Neu, TgMMTV-PyMT, TgWAP-Int3, TgWAP-Tag, and TgC3(1)-Tag) yielded tumors with distinctive and homogeneous expression patterns within each strain. However, in each of four other models (TgWAP-T121, TgMMTV-Wnt1, Brca1Co/Co;TgMMTV-Cre;p53+/- and DMBA-induced), tumors with a variety of histologies and expression profiles developed. In many models, similarities to human breast tumors were recognized, including proliferation and human breast tumor subtype signatures. Significantly, tumors of several models displayed characteristics of human basal-like breast tumors, including two models with induced Brca1 deficiencies. Tumors of other murine models shared features and trended towards significance of gene enrichment with human luminal tumors; however, these murine tumors lacked expression of estrogen receptor (ER) and ER-regulated genes. TgMMTV-Neu tumors did not have a significant gene overlap with the human HER2+/ER- subtype and were more similar to human luminal tumors. CONCLUSION: Many of the defining characteristics of human subtypes were conserved among the mouse models. Although no single mouse model recapitulated all the expression features of a given human subtype, these shared expression features provide a common framework for an improved integration of murine mammary tumor models with human breast tumors.