Molecular portraits of breast cancer: tumour subtypes as distinct disease entities

MicroRNA-30c-2-3p negatively regulates NF-κB signaling and cell cycle progression through downregulation of TRADD and CCNE1 in breast cancer

Nuclear Factor kappa B (NF-κB) signaling is frequently deregulated in a variety of cancers and is constitutively active in estrogen receptor negative (ER-) breast cancer subtypes. These molecular subtypes of breast cancer are associated with poor overall survival. We focused on mechanisms of NF-κB regulation by microRNAs (miRNAs), which regulate eukaryotic gene expression at the post-transcriptional level. In a previous genome-wide miRNA screen, we had identified miR-30c-2-3p as one of the strongest negative regulators of NF-κB signaling. Here we have uncovered the underlying molecular mechanisms and its consequences in breast cancer. In vitro results show that miR-30c-2-3p directly targets both TNFRSF1A-associated via death domain (TRADD), an adaptor protein of the TNFR/NF-κB signaling pathway, and the cell cycle protein Cyclin E1 (CCNE1). Ectopic expression of miR-30c-2-3p downregulated essential cytokines IL8, IL6, CXCL1, and reduced cell proliferation as well as invasion in MDA-MB-231 breast cancer cells. RNA interference (RNAi) induced silencing of TRADD phenocopied the effects on invasion and cytokine expression caused by miR-30c-2-3p, while inhibition of CCNE1 phenocopied the effects on cell proliferation. We further confirmed the tumor suppressive role of this miRNA using a dataset of 781 breast tumors, where higher expression was associated with better survival in breast cancer patients. In summary we have elucidated the mechanism by which miR-30c-2-3p negatively regulates NF-κB signaling and cell cycle progression in breast cancer.

Loss of estrogen-regulated microRNA expression increases HER2 signaling and is prognostic of poor outcome in luminal breast cancer

Among the genes regulated by estrogen receptor (ER) are miRNAs that play a role in breast cancer signaling pathways. To determine whether miRNAs are involved in ER-positive breast cancer progression to hormone independence, we profiled the expression of 800 miRNAs in the estrogen-dependent human breast cancer cell line MCF7 and its estrogen-independent derivative MCF7:2A (MCF7:2A) using NanoString. We found 78 miRNAs differentially expressed between the two cell lines, including a cluster comprising let-7c, miR99a, and miR125b, which is encoded in an intron of the long noncoding RNA LINC00478. These miRNAs are ER targets in MCF7 cells, and nearby ER binding and their expression are significantly decreased in MCF7:2A cells. The expression of these miRNAs was interrogated in patient samples profiled in The Cancer Genome Atlas (TCGA). Among luminal tumors, these miRNAs are expressed at higher levels in luminal A versus B tumors. Although their expression is uniformly low in luminal B tumors, they are lost only in a subset of luminal A patients. Interestingly, this subset with low expression of these miRNAs had worse overall survival compared with luminal A patients with high expression. We confirmed that miR125b directly targets HER2 and that let-7c also regulates HER2 protein expression. In addition, HER2 protein expression and activity are negatively correlated with let-7c expression in TCGA. In summary, we identified an ER-regulated miRNA cluster that regulates HER2, is lost with progression to estrogen independence, and may serve as a biomarker of poor outcome in ER(+) luminal A breast cancer patients.

Metaplastic breast carcinoma: a heterogeneous disease

The aim of this study is to evaluate clinicopathologic characteristics and the multi-disciplinary treatment results of metaplastic breast cancer (MBC) patients treated in a single institute. Seventeen female patients with MBC treated in our department between June 2000 and January 2012 were identified and retrospectively evaluated. The median age at diagnosis was 46 years (range, 26-66 years). The median tumor size at diagnosis was 3.5 cm (range 1.5-12 cm). Six (35%) patients underwent breast conservation surgery and 11 (65%) mastectomy. Axillary lymph node metastasis was found in 6 (35%) patients. Twelve (71%) had triple negative tumors. Postoperative RT and systemic adjuvant treatment was given to all patients accordingly to stage and biological characteristics. Median follow-up time was 27 months (range, 12-151 months). At the time of this analysis, 14 (82%) patients were alive with no evidence of disease, and 1 (6%) was alive with disease. The 3-year OS was 91% and 5-year 80%, and DFS rates were 76% and 76%, respectively. Despite the young age of our patients with mostly high grade tumors, larger tumor size and higher rates of lymph node metastasis, the survival outcomes in our study are favorable in comparison with previously reported series.

The impact of Oncotype DX testing on breast cancer management and chemotherapy prescribing patterns in a tertiary referral centre

INTRODUCTION

The use of chemotherapy in node-negative, (O)Estrogen Receptor (ER)-positive breast cancer has changed significantly since the introduction of Oncotype DX to determine systemic recurrence risk based on tumour genomic signature.

AIMS

This study aims to

METHODS

A cohort study was undertaken, including consecutive patients with early node-negative, ER-positive breast cancer diagnosed between 2006 and May 2013, including a period of prospective clinical trial (Trial Assigning Individualised Options for Treatment (TAILORx)) recruitment. Data were collected regarding patient demographics, tumour clinico-pathological features, Oncotype DX use and recurrence score and chemotherapy use. All therapeutic decisions were made following multidisciplinary discussion, with adherence to guidelines and consideration of trial protocol and Oncotype DX recurrence scores.

RESULTS

479 consecutive patients were included in the study, of whom 241 (50%) underwent Oncotype DX testing, 97 as part of the TAILORx clinical trial. Oncotype DX testing began on a trial basis in 2007 and until October 2011, only patients enrolled on TAILORx availed of genomic profiling. From October 2011, Oncotype DX was used in all eligible patients as per National Cancer Control Programme (NCCP) guidelines. A total of 216 (45%) patients received chemotherapy. The use of chemotherapy changed in inverse proportion to the availability of the genomic assay. Of those patients in whom Oncotype DX was utilised, 138 (57%) were spared chemotherapy.

CONCLUSION

This study validates the use of molecular testing in the rationalisation of systemic therapy.

Association between mammographic density and basal-like and luminal A breast cancer subtypes

Introduction

Mammographic density is a strong risk factor for breast cancer overall, but few studies have examined the association between mammographic density and specific subtypes of breast cancer, especially aggressive basal-like breast cancers. Because basal-like breast cancers are less frequently screen-detected, it is important to understand how mammographic density relates to risk of basal-like breast cancer.

Methods

We estimated associations between mammographic density and breast cancer risk according to breast cancer subtype. Cases and controls were participants in the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). A total of 491 cases had mammograms within five years prior to and one year after diagnosis and 528 controls had screening or diagnostic mammograms close to the dates of selection into CBCS. Mammographic density was reported to the CMR using Breast Imaging Reporting and Data System categories. The expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 1 and 2 (HER1 and HER2), and cytokeratin 5/6 (CK5/6) were assessed by immunohistochemistry and dichotomized as positive or negative, with ER+ and/or PR+, and HER2- tumors classified as luminal A and ER-, PR-, HER2-, HER1+ and/or CK5/6+ tumors classified as basal-like breast cancer. Triple negative tumors were defined as negative for ER, PR and HER2. Of the 491 cases 175 were missing information on subtypes; the remaining cases included 181 luminal A, 17 luminal B, 48 basal-like, 29 ER-/PR-/HER2+, and 41 unclassified subtypes. Odds ratios comparing each subtype to all controls and case-case odds ratios comparing mammographic density distributions in basal-like to luminal A breast cancers were estimated using logistic regression.

Results

Mammographic density was associated with increased risk of both luminal A and basal-like breast cancers, although estimates were imprecise. The magnitude of the odds ratio associated with mammographic density was not substantially different between basal-like and luminal A cancers in case–control analyses and case-case analyses (case-case OR = 1.08 (95% confidence interval: 0.30, 3.84)).

Conclusions

These results suggest that risk estimates associated with mammographic density are not distinct for separate breast cancer subtypes (basal-like/triple negative vs. luminal A breast cancers). Studies with a larger number of basal-like breast cancers are needed to confirm our findings.

Indolylmethylene benzo[h]thiazolo[2,3-b]quinazolinones: synthesis, characterization and evaluation of anticancer and antimicrobial activities

A series of novel 10-((1H-indol-3-yl)methylene)-7-aryl-7,10-dihydro-5H-benzo[h]thiazolo[2,3-b]quinazolin-9(6H)-ones (8a-t) have been synthesized in good yields by the reaction of benzo[h]quinazoline-2(1H)-thiones (4a-f) with 2-chloro-N-phenylacetamide (5) followed by Knoevenagel condensation with various indole-3-carbaldehydes (7a-d) under conventional method. All the synthesized compounds were characterized by spectral studies and screened for their in vitro anticancer and antimicrobial activities. Compound 8c has exhibited excellent activity against MCF-7 (breast cancer cell line) than the standard drug Doxorubicin. Compound 8d against both the cancer cell lines, 8q against MCF-7 and 8c, 8h against HepG2 have also shown good activity. Remaining compounds have shown moderate activity against both the cell lines. Antimicrobial activity revealed that, the compound 8q and 8t against Staphylococcus aureus and 8i, 8k, 8l, 8q &8t against Klebsiella pneumoniae have shown equipotent activity on comparing with the standard drug Streptomycin. Remaining compounds have shown significant antibacterial and comparable antifungal activities against all the tested microorganisms.

Lessons learned from the intrinsic subtypes of breast cancer in the quest for precision therapy

BACKGROUND

Wide variability in breast cancer, between patients and within each individual neoplasm, adds confounding complexity to the treatment of the disease. In clinical practice, hormone receptor status has been used to classify breast tumours and to guide treatment. Modern classification systems should take the wide tumour heterogeneity into account to improve patient outcome.

METHODS

This article reviews the identification of the intrinsic molecular subtypes of breast cancer, their prognostic and therapeutic implications, and the impact of tumour heterogeneity on cancer progression and treatment. The possibility of functionally addressing tumour-specific characteristics in in vivo models to inform decisions for precision therapies is also discussed.

RESULTS

Despite the robust breast tumour classification system provided by gene expression profiling, heterogeneity is also evident within these molecular portraits. A complicating factor in breast cancer classification is the process of selective clonality within developing neoplasms. Phenotypically and functionally distinct clones representing the intratumour heterogeneity might confuse molecular classification. Molecular portraits of the heterogeneous primary tumour might not necessarily reflect the subclone of cancer cells that causes the disease to relapse. Studies of reciprocal relationships between cancer cell subpopulations within developing tumours are therefore needed, and are possible only in genetically engineered mouse models or patient-derived xenograft models, in which the treatment-induced selection pressure on individual cell clones can be mimicked.

CONCLUSION

In the future, more refined classifications, based on integration of information at several molecular levels, are required to improve treatment guidelines. Large-scale translational research efforts paved the way for identification of the intrinsic subtypes, and are still fundamental for ensuring future progress in cancer care.

In vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) for metabolic profiling of human breast cancer xenografts

PURPOSE

To study cancer associated with abnormal metabolism of phospholipids, of which several have been proposed as biomarkers for malignancy or to monitor response to anticancer therapy. We explored 3D (31) P magnetic resonance spectroscopic imaging (MRSI) at high magnetic field for in vivo assessment of individual phospholipids in two patient-derived breast cancer xenografts representing good and poor prognosis (luminal- and basal-like tumors).

MATERIALS AND METHODS

Metabolic profiles from luminal-like and basal-like xenograft tumors were obtained in vivo using 3D (31) P MRSI at 11.7T and from tissue extracts in vitro at 14.1T. Gene expression analysis was performed in order to support metabolic differences between the two xenografts.

RESULTS

In vivo (31) P MR spectra were obtained in which the prominent resonances from phospholipid metabolites were detected at a high signal-to-noise ratio (SNR >7.5). Metabolic profiles obtained in vivo were in agreement with those obtained in vitro and could be used to discriminate between the two xenograft models, based on the levels of phosphocholine, phosphoethanolamine, glycerophosphocholine, and glycerophosphoethanolamine. The differences in phospholipid metabolite concentration could partly be explained by gene expression profiles.

CONCLUSION

Noninvasive metabolic profiling by 3D (31) P MRSI can discriminate between subtypes of breast cancer based on different concentrations of choline- and ethanolamine-containing phospholipids.

Molecular subtyping of invasive bladder cancer: time to divide and rule?

Therapeutic decisions for muscle-invasive bladder cancer (MIBC) are largely based on histopathologic characteristics. In this issue of Cancer Cell, Choi and colleagues report three molecular subtypes of MIBC with the potential to guide prognosis, patient stratification, and treatment.

Interplay of choline metabolites and genes in patient-derived breast cancer xenografts

Introduction

Dysregulated choline metabolism is a well-known feature of breast cancer, but the underlying mechanisms are not fully understood. In this study, the metabolomic and transcriptomic characteristics of a large panel of human breast cancer xenograft models were mapped, with focus on choline metabolism.

Methods

Tumor specimens from 34 patient-derived xenograft models were collected and divided in two. One part was examined using high-resolution magic angle spinning (HR-MAS) MR spectroscopy while another part was analyzed using gene expression microarrays. Expression data of genes encoding proteins in the choline metabolism pathway were analyzed and correlated to the levels of choline (Cho), phosphocholine (PCho) and glycerophosphocholine (GPC) using Pearson’s correlation analysis. For comparison purposes, metabolic and gene expression data were collected from human breast tumors belonging to corresponding molecular subgroups.

Results

Most of the xenograft models were classified as basal-like (N = 19) or luminal B (N = 7). These two subgroups showed significantly different choline metabolic and gene expression profiles. The luminal B xenografts were characterized by a high PCho/GPC ratio while the basal-like xenografts were characterized by highly variable PCho/GPC ratio. Also, Cho, PCho and GPC levels were correlated to expression of several genes encoding proteins in the choline metabolism pathway, including choline kinase alpha (CHKA) and glycerophosphodiester phosphodiesterase domain containing 5 (GDPD5). These characteristics were similar to those found in human tumor samples.

Conclusion

The higher PCho/GPC ratio found in luminal B compared with most basal-like breast cancer xenograft models and human tissue samples do not correspond to results observed from in vitro studies. It is likely that microenvironmental factors play a role in the in vivo regulation of choline metabolism. Cho, PCho and GPC were correlated to different choline pathway-encoding genes in luminal B compared with basal-like xenografts, suggesting that regulation of choline metabolism may vary between different breast cancer subgroups. The concordance between the metabolic and gene expression profiles from xenograft models with breast cancer tissue samples from patients indicates that these xenografts are representative models of human breast cancer and represent relevant models to study tumor metabolism in vivo.

Immunohistochemistry-based subtyping of breast carcinoma in Egyptian women: a clinicopathologic study on 125 patients

Breast carcinoma is a heterogeneous disease affected by patients' ethnicity. Gene expression analysis identified several molecular subtypes, and similar subtyping has now been found to be feasible using immunohistochemistry. This study estimated the distribution of intrinsic breast cancer subtypes using estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2 (Her2/neu), and cytokeratin 5/6 immunostaining in a cohort of 125 Egyptian women diagnosed as having invasive breast carcinoma. Associations with clinicopathologic variables and the prognostic markers Bcl-2 and Cyclin D1 were investigated and statistically analyzed. Population difference in breast cancer subtypes was detected, suggesting etiologic and genetic heterogeneity among demographic groups. As reported worldwide, most tumors were luminal A (39.2%), but basal-like and unclassified subtypes had higher proportions among our cohort (16.8% and 16%, respectively), particularly in premenopausal patients (P = .0001), in contrast to postmenopausal African Americans, premenopausal European Americans, and other populations. Her2-overexpressing subtype was the least common subtype (13.65%) among our patients, although it is more common in Asians. Basal-like and unclassified carcinomas were more frequently grade 3 neoplasms (P = .035). Lobular histology was distributed among luminal A, B and unclassified subtypes (P = .006). The highest frequency of nodal positivity was associated with Her2 overexpressing carcinomas (94.1%, P = .0001). Luminal and unclassified carcinomas more likely expressed Bcl-2 (P = .011) and Cyclin D1 (P = .0001), whereas basal and Her2 subtypes had the lowest expression levels. Immunohistochemistry-based subtyping can be helpful in separating breast carcinoma into subtypes that vary in distribution among different populations. These subtypes have distinct clinicopathologic features and diverse prognostication, which may imply different therapeutic options for each subtype.

Differentiation between benign and malignant breast lesions using quantitative diffusion-weighted sequence on 3 T MRI

AIM

To investigate the capability and diagnostic accuracy of diffusion-weighted imaging (DWI) in differentiating benign from malignant breast lesions using 3 T magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Women with suspicious or indeterminate breast lesions detected at MRI, mammogram and/or ultrasound were recruited for dynamic contrast-enhanced (DCE)-MRI and DWI prior to their biopsy. Image fusion of DCE-MRI with apparent diffusion coefficient (ADC) map was utilized to select the region of interest (ROI) for ADC calculation in the area that showed the most avid enhancement. DWI was performed using two sets of b-values at 500 and 1000 s/mm(2), respectively.

RESULTS

Fifty women were recruited and the final analysis comprised 44 breast lesions, 31 of which were malignant and 13 were benign. Significant results were obtained between ADC values of benign and malignant lesions (p < 0.001). The cut-off ADC values for benign and malignant lesions were 1.21 × 10(-3) mm(2)/s for b = 500 s/mm(2) and 1.22 × 10(-3) mm(2)/s for b = 1000 s/mm(2), respectively. The sensitivity of DCE-MRI alone was 100% with a specificity of 66.7%. When DCE-MRI was combined with b = 1000 s/mm(2), the specificity rose to 100%, while only mildly affecting sensitivity (90.6%). No significant correlation was found between ADC values and prognostic factors, such as lymph node metastasis, tumour size, oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status, and tumour grades.

CONCLUSION

The present study provides consistent evidence to support DWI as a diagnostic tool for breast lesion characterization. A combination of DCE-MRI with DWI is suggested to improve the sensitivity and specificity of lesion characterization.

Locoregional and distant recurrences after breast conserving therapy in patients with triple-negative breast cancer: a meta-analysis

BACKGROUND

With higher incidence of recurrence, ongoing dispute exists on whether triple-negative breast cancer (TNBC) is a good candidate for breast conserving therapy (BCT).

OBJECTIVE

We aimed to appraise the safety of BCT in treating TNBC, in comparison with modified radical mastectomy. The prognostic effect of TN phenotype in conservatively managed patients was also assessed.

METHODS

A systematic search for studies regarding recurrences in patients with TNBC or treated by BCT was conducted up to March 2013. Summary relative risks (RRs) for ipsilateral locoregional recurrence (ILRR) and distant metastasis (DM) were calculated in a fixed-effects model.

RESULTS

Twenty-two studies concerning 15,312 breast cancer patients were analyzed. In the cohort of TNBC, the patients receiving BCT were less likely to develop ILRR and DM in comparison with mastectomy (RR 0.75, 95% CI 0.65-0.87; RR 0.68, 95% CI 0.60-0.76). In the cohort of BCT, the TN subtype increased the risks of both ILRR and DM than non-TN subtypes (RR 1.88, 95% CI 1.58-2.22; RR 2.12, 95% CI 1.72-2.62). Further subgroup analyses of BCT cohort revealed that the luminal phenotype had the most favorable prognosis. Notably, TN subtype was less likely to develop ILRR than HER-2 subtype (RR 0.69, 95% CI 0.53-0.91), there was no difference in DM rate between them.

CONCLUSIONS

BCT benefits patients with TNBC than mastectomy does. However, TN subtype predicts a poorer prognosis than non-TN subtype, suggesting more aggressive adjuvant therapy for TNBC be established in future trials.

Breast cancer stem cells

Cancer metastasis, resistance to therapies and disease recurrence are significant hurdles to successful treatment of breast cancer. Identifying mechanisms by which cancer spreads, survives treatment regimes and regenerates more aggressive tumors are critical to improving patient survival. Substantial evidence gathered over the last 10 years suggests that breast cancer progression and recurrence is supported by cancer stem cells (CSCs). Understanding how CSCs form and how they contribute to the pathology of breast cancer will greatly aid the pursuit of novel therapies targeted at eliminating these cells. This review will summarize what is currently known about the origins of breast CSCs, their role in disease progression and ways in which they may be targeted therapeutically.

Molecular and cellular heterogeneity in breast cancer: challenges for personalized medicine

Breast cancer is noted for disparate clinical behaviors and patient outcomes, despite common histopathological features at diagnosis. Molecular pathogenesis studies suggest that breast cancer is a collection of diseases with variable molecular underpinnings that modulate therapeutic responses, disease-free intervals, and long-term survival. Traditional therapeutic strategies for individual patients are guided by the expression status of the estrogen and progesterone receptors (ER and PR) and human epidermal growth factor receptor 2 (HER2). Although such methods for clinical classification have utility in selection of targeted therapies, short-term patient responses and long-term survival remain difficult to predict. Molecular signatures of breast cancer based on complex gene expression patterns have utility in prediction of long-term patient outcomes, but are not yet used for guiding therapy. Examination of the correspondence between these methods for breast cancer classification reveals a lack of agreement affecting a significant percentage of cases. To realize true personalized breast cancer therapy, a more complete analysis and evaluation of the molecular characteristics of the disease in the individual patient is required, together with an understanding of the contributions of specific genetic and epigenetic alterations (and their combinations) to management of the patient. Here, we discuss the molecular and cellular heterogeneity of breast cancer, the impact of this heterogeneity on practical breast cancer classification, and the challenges for personalized breast cancer treatment.

Novel Integrative Genomics Approach for Associating GWAS Information with Intrinsic Subtypes of Breast Cancer

Genome-wide association studies (GWAS) have achieved great success in identifying common variants associated with increased risk of developing breast cancer. However, GWAS do not typically provide information about the broader context in which genetic variants operate in different subtypes of breast cancer. The objective of this study was to determine whether genes containing single nucleotide polymorphisms (SNPs, herein called genetic variants) are associated with different subtypes of breast cancer. Additionally, we sought to identify gene regulator networks and biological pathways enriched for these genetic variants. Using supervised analysis, we identified 201 genes that were significantly associated with the six intrinsic subtypes of breast cancer. The results demonstrate that integrative genomics analysis is a powerful approach for linking GWAS information to distinct disease states and provide insights about the broader context in which genetic variants operate in different subtypes of breast cancer.

Are breast cancer subtypes prognostic for nodal involvement and associated with clinicopathologic features at presentation in early-stage breast cancer?

BACKGROUND

Breast cancer subtypes (BCS) determined from immunohistochemical staining have been correlated with molecular subtypes and associated with prognosis and outcomes, but there are limited data correlating these BCS and axillary node involvement. This study was conducted to assess whether BCS predicted for nodal metastasis or was associated with other clinicopathologic features at presentation.

METHODS

Patients with stage I/II disease who underwent breast-conserving surgery and axillary surgical assessment with available tissue blocks underwent a institutional pathological review and construction of a tissue microarray. The slides were stained for estrogen receptor, progesterone receptor, and HER-2/neu (HER-2) for classification into BCS. Nodal involvement and other clinicopathologic features were analyzed to assess associations between BCS and patient and tumor characteristics. Outcomes were calculated a function of BCS.

RESULTS

The study cohort consisted of 453 patients (luminal A 48.6%, luminal B 16.1%, HER-2 11.0%, triple negative 24.2%), of which 22% (n=113) were node positive. There were no significant associations with BCS and pN stage, node positivity, or absolute number of nodes involved (p>0.05 for all). However, there were significant associations with subtype and age at presentation (p<0.001), method of detection (p=0.049), tumor histology (p<0.001), race (p=0.041), and tumor size (pT stage, p<0.001) by univariate and multivariate analysis. As expected, 10-year outcomes differed by BCS, with triple negative and HER-2 subtypes having the worse overall (p=0.03), disease-free (p=0.03), and distant metastasis-free survival (p<0.01).

CONCLUSIONS

There is a significant association between BCS and age, T stage, histology, method of detection, and race, but no associations to predict nodal involvement. If additionally validated, these findings suggest that BCS may not be a useful prognostic variable for influencing regional management considerations.

Biphasic papillary and lobular breast carcinoma with PIK3CA and IDH1 mutations

Morphologic "special types" of breast carcinomas have been recognized for many years, and their molecular and genetic properties have not been specifically studied until recently. Lobular carcinoma lacks functional E-cadherin expression but shares molecular similarities with low-grade invasive ductal carcinomas. Papillary carcinoma is relatively rare, and molecular features are just being elucidated. We report a case of concurrent invasive lobular and papillary carcinoma, the latter with extensive nodal involvement. Multiplex screening for activating point mutations identified different point mutations in the distinct morphologic components: lobular PIK3CA H1047R, papillary; PIK3CA Q546P, and IDH1 R132H. These molecular data favor coincidental "collision tumors" over clonal evolution. The IDH1 R132H point mutation is common in gliomas and acute myelogenous leukemia, but this has not been previously reported in breast carcinoma. The characterization of activating point mutations in morphologic special types of breast carcinoma may suggest avenues amenable to targeted therapy.

Biomarkers of residual disease, disseminated tumor cells, and metastases in the MMTV-PyMT breast cancer model

Cancer metastases arise in part from disseminated tumor cells originating from the primary tumor and from residual disease persisting after therapy. The identification of biomarkers on micro-metastases, disseminated tumors, and residual disease may yield novel tools for early detection and treatment of these disease states prior to their development into metastases and recurrent tumors. Here we describe the molecular profiling of disseminated tumor cells in lungs, lung metastases, and residual tumor cells in the MMTV-PyMT breast cancer model. MMTV-PyMT mice were bred with actin-GFP mice, and focal hyperplastic lesions from pubertal MMTV-PyMT;actin-GFP mice were orthotopically transplanted into FVB/n mice to track single tumor foci. Tumor-bearing mice were treated with TAC chemotherapy (docetaxel, doxorubicin, cyclophosphamide), and residual and relapsed tumor cells were sorted and profiled by mRNA microarray analysis. Data analysis revealed enrichment of the Jak/Stat pathway, Notch pathway, and epigenetic regulators in residual tumors. Stat1 was significantly up-regulated in a DNA-damage-resistant population of residual tumor cells, and a pre-existing Stat1 sub-population was identified in untreated tumors. Tumor cells from adenomas, carcinomas, lung disseminated tumor cells, and lung metastases were also sorted from MMTV-PyMT transplant mice and profiled by mRNA microarray. Whereas disseminated tumors cells appeared similar to carcinoma cells at the mRNA level, lung metastases were genotypically very different from disseminated cells and primary tumors. Lung metastases were enriched for a number of chromatin-modifying genes and stem cell-associated genes. Histone analysis of H3K4 and H3K9 suggested that lung metastases had been reprogrammed during malignant progression. These data identify novel biomarkers of residual tumor cells and disseminated tumor cells and implicate pathways that may mediate metastasis formation and tumor relapse after therapy.

Gene expression profile analysis of t1 and t2 breast cancer reveals different activation pathways

Breast cancers today are of predominantly T1 (0.1 ≥ 2.0 cm) or T2 (>2 ≤ 5 cm) categories due to early diagnosis. Molecular profiling using microarrays has led to the notion of breast cancer as a heterogeneous disease both clinically and molecularly. Given the prognostic power and clinical use of tumor size, the purpose of this study was to search for molecular signatures characterizing clinical T1 and T2. In total 46 samples were included in the discovery dataset. After adjusting for hormone receptor status, lymph node status, grade, and tumor subclass 441 genes were differently expressed between T1 and T2 tumors. Focal adhesion and extracellular matrix receptor interaction were upregulated in the smaller tumors while p38MAPK signaling and immune-related pathways were more dominant in the larger tumors. The T-size signature was then tested on a validation set of 947 breast tumor samples. Using the T-size expression signatures instead of tumor size leads to a significant difference in risk for distant metastases (P < 0.001). If further confirmed, this molecular signature can be used to select patients with tumor category T1 who may need more aggressive treatment and patients with tumor category T2 who may have less benefit from it.

Biclustering reveals breast cancer tumour subgroups with common clinical features and improves prediction of disease recurrence

BACKGROUND

Many studies have revealed correlations between breast tumour phenotypes, variations in gene expression, and patient survival outcomes. The molecular heterogeneity between breast tumours revealed by these studies has allowed prediction of prognosis and has underpinned stratified therapy, where groups of patients with particular tumour types receive specific treatments. The molecular tests used to predict prognosis and stratify treatment usually utilise fixed sets of genomic biomarkers, with the same biomarker sets being used to test all patients. In this paper we suggest that instead of fixed sets of genomic biomarkers, it may be more effective to use a stratified biomarker approach, where optimal biomarker sets are automatically chosen for particular patient groups, analogous to the choice of optimal treatments for groups of similar patients in stratified therapy. We illustrate the effectiveness of a biclustering approach to select optimal gene sets for determining the prognosis of specific strata of patients, based on potentially overlapping, non-discrete molecular characteristics of tumours.

RESULTS

Biclustering identified tightly co-expressed gene sets in the tumours of restricted subgroups of breast cancer patients. The co-expressed genes in these biclusters were significantly enriched for particular biological annotations and gene regulatory modules associated with breast cancer biology. Tumours identified within the same bicluster were more likely to present with similar clinical features. Bicluster membership combined with clinical information could predict patient prognosis in conditional inference tree and ridge regression class prediction models.

CONCLUSIONS

The increasing clinical use of genomic profiling demands identification of more effective methods to segregate patients into prognostic and treatment groups. We have shown that biclustering can be used to select optimal gene sets for determining the prognosis of specific strata of patients.

Clinicopathologic features and prognosis of triple-negative breast cancer in patients 40 years of age and younger in Saudi Arabia

BACKGROUND AND OBJECTIVES

Triple-negative breast cancer (TNBC) has a poor prognosis and overall survival (OS) compared to other types of breast cancer tumors. However, there is to date no evidence that this is also the case in Saudi Arabia.

DESIGN AND SETTING

Retrospective review of breast cancer patients who were treated from January 2001 to December 2008 (517 patients) at the King AbdulAziz Medical City, Riyadh, Saudi Arabia.

PATIENTS AND METHODS

Patients were selected as TNBC if all three markers of estrogen receptor (ER), progesterone receptor (PR) and the human epidermal growth factor (HER2) tested by immunohistochemistry as negative. They were then age- and stage-matched, and compared with non-TNBC patients to examine differences, if any, in their clinicopathologic features, prognosis and OS.

RESULTS

Twenty-six patients with a follow up time of at least three years were identified as TNBC. Thirty-three patients who were age- and stage-matched were selected as the non-TNBC controls. Clinicopathologic results illustrated significantly more grade 3 tumors (P=.02) and CK 5/6 expression (P<.001) in the TNBC group compared to the non-TNBC group. TNBC patients aged ≤40 years showed a significantly worse prognosis and OS compared to TNBC patients aged >40 years (P=.01), and when compared to the non-TNBC group (P=.04).

CONCLUSION

The incidence of TNBC in our cohort is similar to what has been illustrated in previous studies in Western population. There was no significant difference in 3-year survival between TNBC and non-TNBC groups. However, the aggressiveness of this type of tumor and OS is significantly higher in younger patients aged ≤40 years, compared to those over 40 years of age.

[Regional recurrence of triple-negative breast cancer: interest of systematic adjuvant lymph node irradiation?]

OBJECTIVE

To evaluate the percentage of regional recurrence (RR) in patients with triple-negative (TN) N0 breast cancer in order to consider the interests of a systematic adjuvant nodal irradiation.

PATIENTS AND METHODS

Between February 1996 and June 2009, 249 patients were treated for TN breast cancer in Léon-Bérard center (Lyon, France). All patients received first surgical treatment followed or not by chemotherapy or radiotherapy. We excluded patients with metastasis at diagnosis, patients who were initially irradiated regional lymph node, patients which ER, PR and/or HER2 status was not known and patients who didn't have standard treatment. Ultimately, 100 patients were included.

RESULTS

Two patients (2%) developed regional recurrence (1 sub and supraclavicular recurrence and 1 supraclavicular recurrence). The median follow-up was 34 months (95% CI: 29,2 to 37,4). The survival rate at 3 years was 98% (95% CI: 90-99). Our study showed no differences in terms of RR between TN cancers and not TN cancers for a median followed up of 34 months.

CONCLUSION

The results of our study do not suggest that patients with TN breast cancer should receive systematic nodal adjuvant radiotherapy.

Immunohistochemical profile and clinical-pathological variables in breast cancer

OBJECTIVE

To describe the main characteristics of women with breast cancer, according to the immunohistochemical profile.

METHODS

The population comprised a hospital cohort, consisting of women diagnosed with breast cancer between 2003 and 2005 (n = 601) and treated at a referral center for cancer care in Juiz de Fora, MG, Brazil. Only 397 women who had complete immunohistochemistry analysis were selected. To define the groups according to the immunohistochemical profile, the assessment of estrogen and progesterone receptors, Ki-67 cell proliferation index, and overexpression of human epidermal growth factor receptor 2 (HER2) was chosen. According to the different phenotypes, five subtypes were defined: luminal A, luminal B HER2 negative, luminal B HER2 positive, triple negative, and HER2 overexpression.

RESULTS

Most patients were white (80.7%) and post-menopausal (64.9%), with a mean age of 57.4 years (± 13.5). At diagnosis, 57.5% had tumor size > 2.0 cm, and 41.7% had lymph node involvement. The most common subtypes were luminal B - HER2 negative (41.8%) and triple negative (24.2%). In the luminal A subtype, 72.1% of patients were post-menopausal, while the highest percentage of premenopausal women were observed in the luminal B - HER2 positive and triple negative subtypes (45.2% and 44.2%, respectively). A higher frequency of tumors > 2.0 cm and lymph node involvement was observed in triple negative and HER2 positive subtypes.

CONCLUSION

This study allowed the distribution assessment of the main clinical and pathological characteristics and those related to health services in a cohort of Brazilian women with breast cancer, according to the immunohistochemical tumor subtypes.

Hypothesized role of pregnancy hormones on HER2+ breast tumor development

Breast cancer incidence rates have declined among older but not younger women; the latter are more likely to be diagnosed with breast cancers carrying a poor prognosis. Epidemiological evidence supports an increase in breast cancer incidence following pregnancy with risk elevated as much as 10 years post-partum. We investigated the association between years since last full-term pregnancy at the time of diagnosis (≤10 or >10 years) and breast tumor subtype in a case series of premenopausal Hispanic women (n = 627). Participants were recruited in the United States, Mexico, and Spain. Cases with known estrogen receptor (ER), progesterone receptor (PR), and HER2 status, with one or more full-term pregnancies ≥1 year prior to diagnosis were eligible for this analysis. Cases were classified into three tumor subtypes according to hormone receptor (HR+ = ER+ and/or PR+; HR- = ER- and PR-) expression and HER2 status: HR+/HER2-, HER2+ (regardless of HR), and triple negative breast cancer. Case-only odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated for HER2+ tumors in reference to HR+/HER2- tumors. Participants were pooled in a mixed-effects logistic regression model with years since pregnancy as a fixed effect and study site as a random effect. When compared to HR+/HER2- cases, women with HER2+ tumors were more likely be diagnosed in the post-partum period of ≤10 years (OR = 1.68; 95 % CI, 1.12-2.52). The effect was present across all source populations and independent of the HR status of the HER2+ tumor. Adjusting for age at diagnosis (≤45 or >45 years) did not materially alter our results (OR = 1.78; 95 % CI, 1.08-2.93). These findings support the novel hypothesis that factors associated with the post-partum breast, possibly hormonal, are involved in the development of HER2+ tumors.

Biological role of NK cells and immunotherapeutic approaches in breast cancer

In recent decades, tumor surveillance by the immune system and its impact on disease outcomes in cancer patients in general and in breast cancer (BC) patients in particular has been documented. Natural killer (NK) cells are central components of the innate immunity and existing data indicate that they play a role in preventing and controlling tumor growth and metastasis. Their biological significance was first recognized by their ability to exert direct cellular cytotoxicity without prior sensitization. This is important in tumors, as transforming events are likely to result in downregulation of self-ligands and expression of stress-induced ligands which can be recognized by NK cells. Their activation also leads to secretion of stimulatory cytokines which participate in cancer elimination by several direct mechanisms as well as by stimulating the adaptive immune system. In this regard, it was recently revealed a dendritic cell (DC)-NK-cell crosstalk which provides another novel pathway linking innate and adaptive immunity. In addition, NK cells are feasible targets of stimulation in immunotherapeutic approaches such as antibody-based strategies and adoptive cell transfer. Nevertheless, NK cells display impaired functionality and capability to infiltrate tumors in BC patients. This review compiles information about NK-cell biology in BC and the attempts which aim to manipulate them in novel therapeutic approaches in this pathology.

Luminal B tumors are the most frequent molecular subtype in breast cancer of North African women: an immunohistochemical profile study from Morocco

Background

Breast cancer may be classified into luminal A, luminal B, HER2+/ER-, basal-like and normal-like subtypes based on gene expression profiling or immunohistochemical (IHC) characteristics. The aim of our study is to show the molecular profile characteristic of breast cancer in the North African population of Morocco. This work showed preliminary results and correlations with clinicopathological and histological parameters. Three hundred and ninety primary breast carcinomas tumor tissues were immunostained for ER, PR, HER2, CK5/6, CK8/18 and Ki67 using paraffin tissue.

Methods

We reviewed 390 cases of breast cancer diagnosed on January 2008 to December 2011 at the Department of pathology, Hassan II teaching hospital, Fez, Morocco. Age, size tumor, metastatic profile, node involvement profile, histological type and immunohistochemical profile were studied.

Results

The average age was 46 years; our patients were diagnosed late with a high average tumor size. Luminal B subtype was more prevalent (41.8%), followed by luminal A (30.5%), basal-like (13, 6%), Her2-overexpressing (9, 2%), and unclassified subtype (4.9%).

Conclusion

This study showed that molecular classification and biological profile may be different according to geographical distribution, to encourage further studies to know the genomic profile of tumors and the environment.

Virtual slide

http://www.diagnosticpathology.diagnomx.eu/vs/1675272504826544

Silencing of miRNA-218 promotes migration and invasion of breast cancer via Slit2-Robo1 pathway

MiRNAs play an important role in regulating tumor migration and invasion, and abnormal expression of miRNAs occurs in various kinds of human cancers. In this essay, it is reported that the level of miRNA-218 decreases in metastatic breast cancer cells, moreover, miRNA-218 suppresses breast cancer cells migration and invasion through binding Robo1 (one of Slit receptors) to its 3'UTR. MiRNA-218 restoration suppresses Robo1 expression and inhibits breast cancer cells invasion and migration. What the results describe is that the function of Robo1 regulated by miRNA-218 may provide a new strategy for inhibiting migration and invasion of breast cancer cells.

Distinct tumor protein p53 mutants in breast cancer subgroups

Tumor protein p53 (TP53) is mutated in approximately 30% of breast cancers, but this frequency fluctuates widely between subclasses. We investigated the p53 mutation status in 572 breast tumors, classified into luminal, basal and molecular apocrine subgroups. As expected, the lowest mutation frequency was observed in luminal (26%), and the highest in basal (88%) tumors. Luminal tumors showed significantly higher frequency of substitutions (82 vs. 65%), notably A/T to G/C transitions (31 vs. 15%), whereas molecular apocrine and basal tumors presented much higher frequencies of complex mutations (deletions/insertions) (36 and 33%, respectively, vs. 18%). Accordingly, missense mutations were significantly more frequent in luminal tumors (75 vs. 54%), whereas basal tumors displayed significantly increased rates of TP53 truncations (43 vs. 25%), resulting in loss of function and/or expression. Interestingly, as basal tumors, molecular apocrine tumors presented with a high rate of complex mutations, but paradoxically, these were not associated with increased frequency of p53 truncation. As in luminal tumors, this could reflect a selective pressure for p53 gain of function, possibly through P63/P73 inactivation. Collectively, these observations point not only to different mechanisms of TP53 alterations, but also to different functional consequences in the different breast cancer subtypes.

Advances in the management of metastatic breast cancer: options beyond first-line chemotherapy

This article provides an overview of recent advances in chemotherapy that may be used for the treatment of patients with locally advanced or metastatic breast cancer (MBC). Key phase ii and iii trial data for eribulin mesylate, ixabepilone, and nab-paclitaxel, published since 2006, are discussed on the basis of recency, depth, and quality.Eribulin mesylate is the first monotherapy to significantly increase overall survival in patients with pretreated MBC, but nab-paclitaxel offers a novel and safer mode of delivery in comparison with standard taxanes. By contrast, the use of ixabepilone will be limited for now, until the associated neurotoxicity can be better managed. Alongside a brief overview of the other major chemotherapies currently in use, we have aimed to provide a Canadian context for how these novel agents may be integrated into clinical practice.

Prevalence of molecular subtypes and prognosis of invasive breast cancer in north-east of Morocco: retrospective study

Background

Breast carcinoma is known as a heterogeneous disease because gene expression analyses identify several subtypes and the molecular profiles are prognostic and predictive for patients. Our aim, in this study, is to estimate the prevalence of breast cancer subtypes and to determine the relationship between clinico-pathological characteristics, overall survival (OS) and disease free survival (DFS) for patients coming from north-east of Morocco.

Methods

We reviewed 366 cases of breast cancer diagnosed between January 2007 to June 2010 at the Department of pathology. Age, size tumor, metastatic profile, node involvement profile, OS and DFS were analyzed on 181 patients. These last parameters were estimated by Kaplan-Meier analysis and log-rank test to estimate outcome differences among subgroups.

Results

The average age was 45 years, our patients were diagnosed late (57% stage III, 17.5% stage IV) with a high average tumor size. Luminal A subtype was more prevalent (53.6%) associated with favorable clinic-pathological characteristics, followed by luminal B (16.4%), Her2-overexpressing (12.6%), basal-like (12.6%) and unclassified subtype (4.9%).

Survival analysis showed a significant difference between subtypes. The triple negative tumors were associated with poor prognosis (49% OS, 39% DFS), whereas the luminal A were associated with a better prognosis (88% OS, 59% DFS). The luminal B and the Her2-overexpressing subtypes were associated with an intermediate prognosis (77% and 75% OS, and 41% and 38% DFS respectively).

Conclusion

This study showed that molecular classification by immunohistochemistry was necessary for therapeutic decision and prognosis of breast carcinoma. The luminal A subtype was associated with favorable biological characteristics and a better prognosis than triple negative tumors that were associated with a poor prognosis and unfavorable clinic-pathological characteristics.

Protein expression changes during human triple negative breast cancer cell line progression to lymph node metastasis in a xenografted model in nude mice

Triple negative breast cancers (TNBC) lacking hormone receptors and HER-2 amplification are very aggressive tumors. Since relevant differences between primary tumors and metastases could arise during tumor progression as evidenced by phenotypic discordances reported for hormonal receptors or HER-2 expression, in this analysis we studied changes that occurred in our TNBC model IIB-BR-G throughout the development of IIB-BR-G-_MTS6 metastasis to the lymph nodes (LN) in nude mice, using an antibody-based protein array to characterize their expression profile. We also analyzed their growth kinetics, migration, invasiveness and cytoskeleton structure in vitro and in vivo.

In vitro IIB-BR-G-_MTS6 cells grew slower but showed higher anchorage independent growth. In vivo IIB-BR-G-_MTS6 tumors grew significantly faster and showed a 100% incidence of LN metastasis after s.c. inoculation, although no metastasis was observed for IIB-BR-G. CCL3, IL1β, CXCL1, CSF2, CSF3, IGFBP1, IL1α, IL6, IL8, CCL20, PLAUR, PlGF and VEGF were strongly upregulated in IIB-BR-G-_MTS6 while CCL4, ICAM3, CXCL12, TNFRSF18, FIGF were the most downregulated proteins in the metastatic cell line. IIB-BR-G-_MTS6 protein expression profile could reflect a higher NFκB activation in these cells. In vitro, IIB-BR-G displayed higher migration but IIB-BR-G-_MTS6 had more elevated matrigel invasion ability. In agreement with that observation, IIB-BR-G-_MTS6 had an upregulated expression of MMP1, MMP9, MMP13, PLAUR and HGF. IIB-BR-G-_MTS6 tumors presented also higher local lymphatic invasion than IIB-BR-G but similar lymphatic vessel densities. VEGFC and VEGFA/B expression were higher both in vitro and in vivo for IIB-BR-G-_MTS6. IIB-BR-G-_MTS6 expressed more vimentin than IB-BR-G cells, which was mainly localized in the cellular extremities and both cell lines are E-cadherin negative.

Our results suggest that IIB-BR-G-_MTS6 cells have acquired a pronounced epithelial-to-mesenchymal transition phenotype. Protein expression changes observed between primary tumor-derived IIB-BR-G and metastatic IIB-BR-G-_MTS6 TNBC cells suggest potential targets involved in the control of metastasis.

Pathologic response to short intensified taxane-free neoadjuvant chemotherapy in patients with highly proliferative operable breast cancer

OBJECTIVES

Breast cancer treatment relies on 3 major phenotypical subtypes, including the triple-negative (TN), HER2-positive, and hormone receptor-positive (estrogen receptor/progesterone receptor) ones. We retrospectively determined the clinical and pathologic response rates to intensified taxane-free neoadjuvant chemotherapy according to these phenotypical classes in a series of patients with highly proliferative operable breast cancer, and examined the patterns of recurrence.

METHODS

Patients with early breast cancer with highly proliferative (S-phase fraction >4%) operable tumors of >3 cm received 4 cycles of intensified neoadjuvant chemotherapy with high-dose cyclophosphamide (doxorubicin 70 mg/m d1, cyclophosphamide 700 mg/m d1/d8, and 5 FU 700 mg/m d1-d5) every 3 weeks.

RESULTS

Fifty-five patients were included in the analysis. Patients with TN phenotype experienced a high pathologic complete response (pCR) rate to intensified chemotherapy in comparison with patients with HER2-positive and estrogen receptor/progesterone receptor tumors (47%, 0%, and 12%, respectively). Forty percent of patients with TN breast cancer recurred after a median follow-up of nearly 11 years, but only 22% of those achieving a pCR.

CONCLUSIONS

A high pCR rate to short intensified neoadjuvant chemotherapy with high-dose cyclophosphamide was achieved in patients with operable highly proliferative TN breast cancer, and pCR was associated with a low rate of recurrence.

Treatment options for metaplastic breast cancer

Metaplastic breast cancer (MBC) is a malignancy characterized by the histologic presence of two or more cellular types, commonly a mixture of epithelial and mesenchymal components. MBC is rare relative to invasive ductal carcinoma (IDC), representing less than 1% of all breast cancers. Other than a lower rate of lymph node metastases, MBC tumors display poorer prognostic features relative to IDC. Due to its low incidence and pathological variability, the ideal treatment paradigm for MBC is unknown. Because of its rarity, MBC has been treated as a variant of IDC. Despite similar treatment regimens, however, patients with MBC have worse outcomes. Recent research is focused on biological differences between MBC and IDC and potential novel targets for chemotherapeutic agents. This paper serves as a summation of current literature on approaches to the multidisciplinary treatment of patients with MBC.

A taxonomy of organ-specific breast cancer metastases based on a protein-protein interaction network

We carried out a systems-level study of the mechanisms underlying organ-specific metastases of breast cancer. We followed a network-based approach using microarray expression data from human breast cancer metastases to select organ-specific proteins that exert a range of functions allowing cell survival and growth in the microenvironment of distant organs. MinerProt, a home-made software application, was used to group organ-specific signatures of brain (1191 genes), bone (1623 genes), liver (977 genes) and lung (254 genes) metastases by function and select the most differentially expressed gene in each function. As a result, we obtained 19 functional representative proteins in brain, 23 in bone, 15 in liver and 9 in lung, with which we constructed four organ-specific protein-protein interaction networks. The network taxonomy included seven proteins that interacted in brain metastasis, which were mainly associated with signal transduction. Proteins related to immune response functions were bone specific, while those involved in proteolysis, signal transduction and hepatic glucose metabolism were found in liver metastasis. No experimental protein-protein interaction was found in lung metastasis; thus, computationally determined interactions were included in this network. Moreover, three of these selected genes (CXCL12, DSC2 and TFDP2) were associated with progression to specific organs when tested in an independent dataset. In conclusion, we present a network-based approach to filter information by selecting key protein functions as metastatic markers or therapeutic targets.

Methylation of HIN-1, RASSF1A, RIL and CDH13 in breast cancer is associated with clinical characteristics, but only RASSF1A methylation is associated with outcome

BACKGROUND

Aberrant promoter CpG island hypermethylation is associated with transcriptional silencing. Tumor suppressor genes are the key targets of hypermethylation in breast cancer and therefore may lead to malignancy by deregulation of cell growth and division. Our previous pilot study with pairs of malignant and normal breast tissues identified correlated methylation of two pairs of genes - HIN-1/RASSFIA and RIL/CDH13 - with expression of estrogen receptors (ER), progesterone receptors (PR), and HER2 (HER2). To determine the impact of methylation on clinical outcome, we have conducted a larger study with breast cancers for which time to first recurrence and overall survival are known.

METHODS

Tumors from 193 patients with early stage breast cancer who received no adjuvant systemic therapy were used to analyze methylation levels of RIL, HIN-1, RASSF1A and CDH13 genes for associations with known predictive and prognostic factors and for impact on time to first recurrence and overall survival.

RESULTS

In this study, we found that ER was associated with RASSF1A methylation (p < 0.001) and HIN-1 methylation (p = 0.002). PR was associated with RIL methylation (p = 0.012), HIN-1 (p = 0.002), and RASSF1A methylation (p = 0.019). Tumor size was associated with RIL and CDH13 methylation (both p = 0.002), and S-phase was associated with RIL methylation (p = 0.036). Only RASSF1A was associated with worse time to first recurrence (p = 0.045) and worse overall survival (p = 0.016) after adjusting for age, tumor size, S-phase, estrogen receptor and progesterone receptor.

CONCLUSIONS

Methylation of HIN-1, RASSF1A, RIL and CDH13 in breast cancers was associated with clinical characteristics, but only RASSF1A methylation was associated with time to first recurrence and overall survival. Our data suggest that RASSF1A methylation could be a potential prognostic biomarker.

JMJD6 is a driver of cellular proliferation and motility and a marker of poor prognosis in breast cancer

Introduction

We developed an analytic strategy that correlates gene expression and clinical outcomes as a means to identify novel candidate oncogenes operative in breast cancer. This analysis, followed by functional characterization, resulted in the identification of Jumonji Domain Containing 6 (JMJD6) protein as a novel driver of oncogenic properties in breast cancer.

Methods

Through microarray informatics, Cox proportional hazards regression was used to analyze the correlation between gene expression and distant metastasis-free survival (DMFS) of patients in 14 independent breast cancer cohorts. JMJD6 emerged as a top candidate gene robustly associated with poor patient survival. Immunohistochemistry, siRNA-mediated silencing, and forced overexpression of JMJD6 in cell-based assays elucidated molecular mechanisms of JMJD6 action in breast cancer progression and shed light on the clinical breast cancer subtypes relevant to JMJD6 action.

Results

JMJD6 was expressed at highest levels in tumors associated with worse outcomes, including ER- and basal-like, Claudin-low, Her2-enriched, and ER⁺ Luminal B tumors. High nuclear JMJD6 protein was associated with ER negativity, advanced grade, and poor differentiation in tissue microarrays. Separation of ER⁺/LN^- patients that received endocrine monotherapy indicated that JMJD6 is predictive of poor outcome in treatment-specific subgroups. In breast cancer cell lines, loss of JMJD6 consistently resulted in suppressed proliferation but not apoptosis, whereas forced stable overexpression increased growth. In addition, knockdown of JMJD6 in invasive cell lines, such as MDA-MB231, decreased motility and invasion, whereas overexpression in MCF-7 cells slightly promoted motility but did not confer invasive growth. Microarray analysis showed that the most significant transcriptional changes occurred in cell-proliferation genes and genes of the TGF-β tumor-suppressor pathway. High proliferation was characterized by constitutively high cyclin E protein levels. The inverse relation of JMJD6 expression with TGF-β₂ could be extrapolated to the breast cancer cohorts, suggesting that JMJD6 may affect similar pathways in primary breast cancer.

Conclusions

JMJD6 is a novel biomarker of tumor aggressiveness with functional implications in breast cancer growth and migration.

Integrating contextual miRNA and protein signatures for diagnostic and treatment decisions in cancer

The promise of personalized medicine is highly dependent on the identification of biomarkers that inform diagnostic decisions and treatment options, as well as on the accurate, rapid and cost-effective detection and interpretation of these biomarkers. miRNAs, which are short noncoding regulatory RNAs, are rapidly emerging as a novel class of biomarkers with a unique set of biological and chemical properties that makes them very appealing candidates for theranostic applications in cancer. Since the utility of some protein-encoding gene biomarkers is already exploited in routine clinical practice, it will be important to identify areas in which miRNAs provide complementary or superior information to these existing (and other translational) biomarkers to enhance the diagnostic, prognostic and predictive power of molecular characterization of tumors. In this article, the challenges and opportunities for integration of miRNA-based assays in the clinical toolkit to improve care and management of patients afflicted with solid tumors will be discussed.

Synthesis of new troglitazone derivatives: anti-proliferative activity in breast cancer cell lines and preliminary toxicological study

Breast cancer is the most prevalent cancer in women. The development of resistances to therapeutic agents and the absence of targeted therapy for triple negative breast cancer motivate the search for alternative treatments. With this aim in mind, we synthesised new derivatives of troglitazone, a compound which was formerly used as an anti-diabetic agent and which exhibits anti-proliferative activity on various cancer cell lines. Among the compounds prepared, some displayed micromolar activity against hormone-dependent and hormone-independent breast cancer cells. Furthermore, the influence of the compounds on the viability of primary cultures of human hepatocytes was evaluated. This enabled us to obtain for the first time interesting structure-toxicity relationships in this family of compounds, resulting in 6b and 8b, which show good anti-proliferative activities and poor toxicity towards hepatocytes, compared to troglitazone.

Breast density, body mass index, and risk of tumor marker-defined subtypes of breast cancer

PURPOSE

Breast density and body mass index (BMI) are correlated attributes and are both potentially modifiable risk factors for breast cancer. However, relationships between these factors and risk of molecularly-defined subtypes of breast cancer have not been established.

METHODS

We used breast density and BMI data collected by the Breast Cancer Surveillance Consortium from 1,054,466 women ages 40 to 84 years receiving mammography, including 13,797 women subsequently diagnosed with breast cancer. Cases were classified into three groups on the basis of expression of the estrogen receptor (ER), progesterone receptor (PR), and HER2:1) ER-positive (ER+, n = 10,026), 2) HER2-expressing (ER-negative/PR-negative/HER2-positive, n = 308), or triple-negative (ER-negative/PR-negative/HER2-negative, n = 705). Using Cox regression, we evaluated subtype-specific associations with breast density and BMI.

RESULTS

Breast density was similarly positively associated with risk of all subtypes, especially among women ages 40 to 64 years. BMI was positively associated with risks of ER+ and triple-negative breast cancer in women ages 50 to 84 who were not users of hormone therapy.

CONCLUSIONS

Breast density is positively associated with breast cancer risk, regardless of disease subtype. Associations with BMI appear to vary more by breast cancer subtype. Additional studies are needed to confirm and further characterize risk factors for HER2-expressing and triple-negative breast cancer.

Incidence of brain metastases as a first site of recurrence among women with triple receptor-negative breast cancer

BACKGROUND

This retrospective study sought to define the incidence of brain metastases as a first site of recurrence among women with triple receptor-negative breast cancer (TNBC).

METHODS

A total of 2448 patients with stage I through III TNBC who were diagnosed between 1990 and 2010 were identified. We computed the cumulative incidence of developing brain metastases as a first site of recurrence at 2 and 5 years. Cox proportional hazards models were fitted to determine factors that could predict for the development of brain metastases as a first site of recurrence. The Kaplan-Meier product limit method was used to compute survival following a diagnosis of brain metastases.

RESULTS

At a median follow-up of 39 months, 115 (4.7%) patients had developed brain metastases as a first site of recurrence. The cumulative incidence at 2 and 5 years was 3.7% (95% confidence interval [CI] = 2.9%-4.5%) and 5.4% (95% CI = 4.4%-6.5%), respectively. Among patients with stage I, II, and III disease, the 2-year cumulative incidence of brain metastases was 0.8%, 3.1%, and 8%, respectively (P < .0001). The 5-year cumulative incidence was 2.8%, 4.6%, and 9.6% among patients with stage I, II, and III disease, respectively (P < .0001). In the multivariable model, patients with stage III disease had a significant increase in the risk of developing brain metastases as a first site of recurrence (hazards ratio = 3.51; 95% CI = 1.85-6.67; P = .0001) compared to patients with stage I disease. Those with stage II disease had a nonsignificant increased risk of developing brain metastases as a first site of recurrence (hazards ratio = 1.61; 95% CI = 0.92-2.81; P = .10) compared with patients with stage I disease. Median survival following a diagnosis of brain metastases was 7.2 months (range, 5.7-9.4 months).

CONCLUSIONS

Patients with nonmetastatic TNBC have a high early incidence of developing brain metastases as a first site of recurrence, which is associated with subsequent poor survival. Patients with stage III TNBC in particular would be an ideal cohort in which to research preventive strategies.

Molecular insights on basal-like breast cancer

Molecular classification of breast cancer (BC) identified diverse subgroups that encompass distinct biological behavior and clinical implications, in particular in relation to prognosis, spread, and incidence of recurrence. Basal-like breast cancers (BLBC) compose up to 15% of BC and are characterized by lack of estrogen receptor (ER), progesterone receptor (PR), and HER-2 amplification with expression of basal cytokeratins 5/6, 14, 17, epidermal growth factor receptor (EGFR), and/or c-KIT. There is an overlap in definition between triple-negative BC and BLBC due to the triple-negative profile of BLBC. Also, most BRCA1-associated BCs are BLBC, triple negative, and express basal cytokeratins (5/6, 14, 17) and EGFR. There is a link between sporadic BLBC (occurring in women without germline BRCA1 mutations) with dysfunction of the BRCA1 pathway. Despite the molecular and clinical similarities, these subtypes respond differently to neoadjuvant therapy. BLBCs are associated with an aggressive phenotype, high histological grade, poor clinical behavior, and high rates of recurrences and/or metastasis. Their molecular features render these tumors especially refractory to anti-hormonal-based therapies and the overall prognosis of this subset remains poor. In this article, the molecular profile, genomic, and epigenetic characteristics as well as BRCA1 pathway dysfunction, clinicopathological behavior, and therapeutic options in BLBC are presented, with emphasis on the discordant findings in current literature.

Molecular characterisation of formalin-fixed paraffin-embedded (FFPE) breast tumour specimens using a custom 512-gene breast cancer bead array-based platform

Background:

Formalin-fixed, paraffin-embedded (FFPE) tumour tissue represents an immense but mainly untapped resource with respect to molecular profiling. The DASL (cDNA-mediated Annealing, Selection, extension, and Ligation) assay is a recently described, RT–PCR-based, highly multiplexed high-throughput gene expression platform developed by Illumina specifically for fragmented RNA typically obtained from FFPE specimens, which enables expression profiling. In order to extend the utility of the DASL assay for breast cancer, we have custom designed and validated a 512-gene human breast cancer panel.

Methods:

The RNA from FFPE breast tumour specimens were analysed using the DASL assay. Breast cancer subtype was defined from pathology immunohistochemical (IHC) staining. Differentially expressed genes between the IHC-defined subtypes were assessed by prediction analysis of microarrays (PAM) and then used in the analysis of two published data sets with clinical outcome data.

Results:

Gene expression signatures on our custom breast cancer panel were very reproducible between replicates (average Pearson's R²=0.962) and the 152 genes common to both the standard cancer DASL panel (Illumina) and our breast cancer DASL panel were similarly expressed for samples run on both panels (average R²=0.877). Moreover, expression of ESR1, PGR and ERBB2 corresponded well with their respective pathology-defined IHC status. A 30-gene set indicative of IHC-defined breast cancer subtypes was found to segregate samples based on their subtype in our data sets and published data sets. Furthermore, several of these genes were significantly associated with overall survival (OS) and relapse-free survival (RFS) in these previously published data sets, indicating that they are biomarkers of the different breast cancer subtypes and the prognostic outcomes associated with these subtypes.

Conclusion:

We have demonstrated the ability to expression profile degraded RNA transcripts derived from FFPE tissues on the DASL platform. Importantly, we have identified a 30-biomarker gene set that can classify breast cancer into subtypes and have shown that a subset of these markers is prognostic of OS and RFS.