Mammary-specific expression of Trim24 establishes a mouse model of human metaplastic breast cancer.

Conditional overexpression of histone reader Tripartite motif containing protein 24 (TRIM24) in mouse mammary epithelia (Trim24) drives spontaneous development of mammary carcinosarcoma tumors, lacking ER, PR and HER2. Human carcinosarcomas or metaplastic breast cancers (MpBC) are a rare, chemorefractory subclass of triple-negative breast cancers (TNBC). Comparison of Trim24 metaplastic carcinosarcoma morphology, TRIM24 protein levels and a derived Trim24 gene signature reveals strong correlation with human MpBC tumors and MpBC patient-derived xenograft (PDX) models.

Comparison of three scoring methods using the FDA-approved 22C3 immunohistochemistry assay to evaluate PD-L1 expression in breast cancer and their association with clinicopathologic factors.

Background: In the evaluation of PD-L1 expression to select patients for anti-PD-1/PD-L1 treatment, uniform guidelines that account for different immunohistochemistry assays, different cell types and different cutoff values across tumor types are lacking. Data on how different scoring methods compare in breast cancer are scant.

Methods: Using FDA-approved 22C3 diagnostic immunohistochemistry assay, we retrospectively evaluated PD-L1 expression in 496 primary invasive breast tumors that were not exposed to anti-PD-1/PD-L1 treatment and compared three scoring methods (TC: invasive tumor cells; IC: tumor-infiltrating immune cells; TCIC: a combination of tumor cells and immune cells) in expression frequency and association with clinicopathologic factors.

Imaging features of triple-negative breast cancers according to androgen receptor status.

Objective: Different molecular subtypes of triple-negative breast cancer (TNBC) have previously been identified through analysis of gene expression profiles. The luminal androgen receptor (LAR) subtype has been shown to have a lower rate of pathologic complete response to neoadjuvant chemotherapy than other TNBC subtypes. The purpose of this study was to determine if the imaging features of TNBCs differ by AR (androgen receptor) status, which is a surrogate immunohistochemical (IHC) marker for the chemoresistant LAR subtype of TNBC.

Comparative Effectiveness of an mTOR-Based Systemic Therapy Regimen in Advanced, Metaplastic and Nonmetaplastic Triple-Negative Breast Cancer.

Background: Triple-negative breast cancer (TNBC) is a heterogeneous disease with subtypes having different "targetable" molecular aberrations. Metaplastic breast cancers (MpBCs) are typically TNBCs and commonly have alterations in the PI3K/Akt/mTOR pathway. We previously reported efficacy for an mTOR-based chemotherapy regimen in MpBC.

A Clinical Feasibility Trial for Identification of Exceptional Responders in Whom Breast Cancer Surgery Can Be Eliminated Following Neoadjuvant Systemic Therapy.

Objective: To determine the accuracy of fine-needle aspiration (FNA) and vacuum-assisted core biopsy (VACB) in assessing the presence of residual cancer in the breast after neoadjuvant systemic therapy (NST).

Summary Background Data: Pathologic complete response (pCR) rates after NST have improved dramatically, suggesting that surgery might be avoided in some patients. Safe avoidance of surgery would require accurate confirmation of no residual invasive/in situ carcinoma.

Role of RPL39 in Metaplastic Breast Cancer.

Background: Metaplastic breast cancer is one of the most therapeutically challenging forms of breast cancer because of its highly heterogeneous and chemoresistant nature. We have previously demonstrated that ribosomal protein L39 (RPL39) and its gain-of-function mutation A14V have oncogenic activity in triple-negative breast cancer and this activity may be mediated through inducible nitric oxide synthase (iNOS). The function of RPL39 and A14V in other breast cancer subtypes is currently unknown.

Targeting the PI3K/AKT/mTOR Pathway for the Treatment of Mesenchymal Triple-Negative Breast Cancer: Evidence From a Phase 1 Trial of mTOR Inhibition in Combination With Liposomal Doxorubicin and Bevacizumab.

Importance: Triple-negative breast cancer (TNBC) classified by transcriptional profiling as the mesenchymal subtype frequently harbors aberrations in the phosphoinositide 3-kinase (PI3K) pathway, raising the possibility of targeting this pathway to enhance chemotherapy response. Up to 30% of mesenchymal TNBC can be classified histologically as metaplastic breast cancer, a chemorefractory group of tumors with a mixture of epithelial and mesenchymal components identifiable by light microscopy. While assays to identify mesenchymal TNBC are under development, metaplastic breast cancer serves as a clinically identifiable surrogate to evaluate potential regimens for mesenchymal TNBC.

Low expression of galectin-3 is associated with poor survival in node-positive breast cancers and mesenchymal phenotype in breast cancer stem cells.

Background: Galectin-3 (Gal3) plays diverse roles in cancer initiation, progression, and drug resistance depending on tumor type characteristics that are also associated with cancer stem cells (CSCs). Recurrence of breast carcinomas may be attributed to the presence of breast CSCs (BCSCs). BCSCs exist in mesenchymal-like or epithelial-like states and the transition between these states endows BCSCs with the capacity for tumor progression.

Transection of Radioactive Seeds in Breast Specimens.

Radioactive seed localization is a new procedure for localizing breast lesions that has several advantages over the standard wire-localization procedure. It is reported to be safe for both patients and medical personnel. Although it is theoretically possible to transect the titanium-encapsulated seed while processing the breast specimen in the pathology laboratory, the likelihood of such an event is thought to be exceedingly low.

Histone deacetylase inhibitor-induced cancer stem cells exhibit high pentose phosphate pathway metabolism.

Purpose: We recently demonstrated that histone deacetylase (HDAC) inhibitors can "reprogram" differentiated triple-negative breast cancer cells to become quiescent stem-like cancer cells. We hypothesized that the metabolic state of such cells differs from that of their differentiated progeny.

Results: In untreated cells, glucose uptake was higher in ALDH+ cells than in ALDH- cells (p = 0.

Improved Axillary Evaluation Following Neoadjuvant Therapy for Patients With Node-Positive Breast Cancer Using Selective Evaluation of Clipped Nodes: Implementation of Targeted Axillary Dissection.

Purpose: Placing clips in nodes with biopsy-confirmed metastasis before initiating neoadjuvant therapy allows for evaluation of response in breast cancer. Our goal was to determine if pathologic changes in clipped nodes reflect the status of the nodal basin and if targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of clipped nodes, improves the false-negative rate (FNR) compared with SLND alone.

Methods: A prospective study of patients with biopsy-confirmed nodal metastases with a clip placed in the sampled node was performed.

Inhibition of the phosphoinositide 3-kinase pathway for the treatment of patients with metastatic metaplastic breast cancer.

Background: Mesenchymal/metaplastic breast cancers (MpBCs) are often triple-negative (TNBC), and chemo-refractory, and can harbor phosphoinositide 3-kinase (PI3kinase) alterations; thus, therapy with mTor inhibitors may demonstrate activity.

Patients And Methods: Patients with mesenchymal/MpBC treated with temsirolimus-based regimens were evaluated. Mutational analyses [polymerase chain reaction (PCR)-based DNA sequencing method, mass spectrometric detection (Sequenom MassARRAY), or next-generation sequencing] as well as loss of phosphatase and tensin homolog (PTEN) (immunohistochemistry) were performed (archived tissue when available).

GATA-binding protein 3 enhances the utility of gross cystic disease fluid protein-15 and mammaglobin A in triple-negative breast cancer by immunohistochemistry.

Aims: We have demonstrated previously that gross cystic disease fluid protein-15 (GCDFP-15) and mammaglobin A (MAM) are of limited utility in triple-negative breast cancer (TNBC). GATA-binding protein 3 (GATA-3) is an emerging breast-associated immunohistochemical (IHC) marker with limited data in TNBC. Here, we examined GATA-3 expression in TNBC in comparison with GCDFP-15 and MAM.

Interobserver variability by pathologists in the distinction between cellular fibroadenomas and phyllodes tumors.

Fibroepithelial lesions with cellular stroma are frequently termed cellular fibroadenomas although criteria for distinguishing them from a phyllodes tumor are vague and subjective. However, the clinical implications and surgical management for these 2 lesions may be different. We randomly selected 21 cases of fibroepithelial lesions sent in consultation to the senior author that were challenging to classify as cellular fibroadenoma or phyllodes tumor.

Targeting RPL39 and MLF2 reduces tumor initiation and metastasis in breast cancer by inhibiting nitric oxide synthase signaling.

We previously described a gene signature for breast cancer stem cells (BCSCs) derived from patient biopsies. Selective shRNA knockdown identified ribosomal protein L39 (RPL39) and myeloid leukemia factor 2 (MLF2) as the top candidates that affect BCSC self-renewal. Knockdown of RPL39 and MLF2 by specific siRNA nanoparticles in patient-derived and human cancer xenografts reduced tumor volume and lung metastases with a concomitant decrease in BCSCs.

Benign papillomas without atypia diagnosed on core needle biopsy: experience from a single institution and proposed criteria for excision.

Background: The management of benign papilloma (BP) without atypia identified on breast core needle biopsy (CNB) is controversial. In this study, we determined the upgrade rate to malignancy for BPs without atypia diagnosed on CNB and whether there are factors associated with upgrade.

Methods: Through our pathology database search, we studied 80 BPs without atypia identified on CNB from 80 patients from 1997 to 2010, including 30 lesions that had undergone excision and 50 lesions that had undergone ≥ 2 years of radiologic follow-up.

Multi-institutional comparison of whole slide digital imaging and optical microscopy for interpretation of hematoxylin-eosin-stained breast tissue sections.

Context: Whole slide imaging (WSI) is now used for educational purposes, for consultation, and for archiving and quantitation of immunostains. However, it is not routinely used for the primary diagnosis of hematoxylin-eosin-stained tissue sections.

Objective: To compare WSI using the Aperio digital pathology system (Aperio Technologies, Inc, Vista, California) with optical microscopy (OM) for the interpretation of hematoxylin-eosin-stained tissue sections of breast lesions.

Primary squamous cell carcinoma of the breast: predictors of locoregional recurrence and overall survival.

Studies evaluating the biological behavior of primary squamous cell carcinoma (SCC) of the breast have yielded inconsistent results, perhaps in part because most studies have not taken into consideration specific histologic subtypes. We identified 21 cases of primary SCC of the breast diagnosed between the years 1985 and 2010 and analyzed the association between particular histologic features and disease outcome. Most tumors (17/21) were moderately or poorly differentiated, and most had a high nuclear grade (15/21).

Gross cystic disease fluid protein-15 and mammaglobin A expression determined by immunohistochemistry is of limited utility in triple-negative breast cancer.

Aims:   In addition to oestrogen and progesterone receptors, gross cystic disease fluid protein-15 (GCDFP-15) and mammaglobin A (MAM) are the most common markers used to identify breast origin by immunohistochemistry. GCDFP-15 expression has been reported in approximately 60% of breast carcinomas and MAM expression in approximately 80%. Data on their expression in triple-negative breast cancer (TNBC) are very limited.

The role for sentinel lymph node dissection after neoadjuvant chemotherapy in patients who present with node-positive breast cancer.

Background: Sentinel lymph node (SLN) dissection has been investigated after neoadjuvant chemotherapy and has shown mixed results. Our objective was to evaluate SLN dissection in node-positive patients and to determine whether postchemotherapy ultrasound could select patients for this technique.

Methods: Between 1994 and 2010, 150 patients with biopsy proven axillary metastasis underwent SLN dissection after chemotherapy and 121 underwent axillary lymph node dissection (ALND).

Tissue-based predictors of germ-line BRCA1 mutations: implications for triaging of genetic testing.

BRCA testing of patients with breast cancer considered at high risk for having a germ-line BRCA mutation usually consists of comprehensive mutational analysis of both BRCA1 and BRCA2. A more cost-effective strategy of triaging patients for analysis of a single gene could be adopted if tissue-based predictors indicated a high risk specifically for either BRCA1 or BRCA2. To identify potentially useful tissue-based predictors of BRCA mutation status in breast cancer, we evaluated multiple histopathologic features of invasive breast carcinoma on archival tissue sections from 196 high-risk patients who had undergone BRCA testing, and we analyzed which individual or combination of features was most associated with BRCA mutations.

Imaging features of primary breast sarcoma.

Objective: This purpose of this study is to describe the imaging findings in patients who presented with a diagnosis of primary breast sarcoma.

Materials And Methods: A search was performed of the pathology database at a single institution for patients with a histopathologic diagnosis of primary breast sarcoma or pure sarcomatoid carcinoma and who underwent preoperative mammography, sonography, or MRI. Patients with malignant phyllodes tumors were excluded.