Typical medullary breast carcinomas have a basal/myoepithelial phenotype

Recognizing invasive breast carcinoma of no special type with medullary pattern

Invasive breast carcinoma of no special type (IBC-NST) with medullary pattern is an uncommon histologic type of invasive breast carcinoma. It is associated with high-grade, poorly differentiated tumor cells that form large sheets of irregular confluent tumor cells associated with a prominent lymphocytic infiltrate. Patients with IBC-NST with medullary pattern are often postmenopausal women with a high body mass index and multiparity. We report the case of a 71-year-old woman who presented for routine screening mammography and breast mass suspicious for malignancy, initially thought to be invasive ductal carcinoma with an associated prominent lymphoid infiltrate. However, it was ultimately diagnosed as IBC-NST with medullary pattern, and radiologic imaging (particularly ultrasound and mammography) along with pathology review were critical in making the diagnosis. We make the case of the importance of radiographic imaging in diagnosing this condition, as the prognosis of IBC-NST with medullary pattern is typically more favorable compared to IBC-NST.

Breast cancer prognosis and P-cadherin expression: systematic review and study-level meta-analysis

OBJECTIVE

P-cadherin can act both as a tumour suppressor and an oncogene. The clinical prognostic value of P-cadherin overexpression in breast cancer (BC) remains unclear. We conducted a study-level meta-analysis to determine whether P-cadherin expression can help predict prognosis in BC.

METHODS

A systematic literature search was performed to review eligible studies and clarify the relationship between P-cadherin overexpression and overall survival (OS), disease-free survival (DFS), pathological features, molecular subtypes and molecular phenotypes in BC.

RESULTS

Thirty-one studies including 12 332 patients were included. P-cadherin overexpression was correlated with significantly worse OS (HR=1.77, p<0.00001) and DFS (HR=1.96, p<0.00001) than P-cadherin-negative. P-cadherin overexpression could lead to high histological grade (OR=3.33, p<0.00001) and lymph node metastasis (OR=1.62, p<0.00001). Moreover, P-cadherin overexpression was associated with low odds of the luminal A subtype and high odds of the human epidermal growth factor receptor-2 (HER2)-positive and triple-negative subtypes. P-cadherin expression led to low expression of oestrogen and progesterone receptor (OR=0.37 and OR=0.36, respectively, both p<0.00001) and high expression of HER2 (OR=2.31, p<0.00001), Ki-67 (OR=2.79, p<0.00001), epidermal growth factor receptor (OR=5.85, p<0.00001) and cytokeratin 5/6 (OR=6.79, p<0.00001).

CONCLUSIONS

P-cadherin was found to be associated with invasiveness and metastasis. P-cadherin expression can probably be a useful biomarker for predicting poor survival and may act as an independent prognostic predictor.

The 21-Gene Recurrence Score in Special Histologic Subtypes of Breast Cancer: A Population-Based Study

CONTEXT.—

Recurrence score (RS) testing was developed and validated in invasive ductal and rare lobular carcinomas, although it is used for all special types of breast cancers.

OBJECTIVE.—

To determine association of histologic type (HT) and RS, specifically high-risk RS.

DESIGN.—

We used RSs linked to Surveillance, Epidemiology, and End Results program registries of invasive breast cancers diagnosed in 2004 through 2015. Multivariable logistic regression was used to evaluate association between HT and high-risk RS. Relationships between HT and low-, intermediate-, and high-risk RS were compared with χ2 test. Kaplan-Meier curves were compared using log-rank test.

RESULTS.—

A total of 110 318 patients had RS testing. Of these, 23 220 (21%) had low, 70 822 (64.2%) intermediate, and 16 276 (14.8%) high RS. Histologic types were 80 476 (73%) ductal, 12 713 (11.5%) lobular, 12 449 (11.3%) mixed, 2151 (2%) mucinous, 610 (0.6%) tubular 382 (0.4%) micropapillary, 365 (0.3%) salivary, 208 (0.2%) papillary, 49 (0.04%) medullary, 26 (0.02%) metaplastic, 26 (0.02%) neuroendocrine, and 863 (0.8%) unknown. The distribution of low-, intermediate-, and high-risk RS was significantly different among HTs. Higher percentages of high-risk RS were identified in patients with ductal, medullary, and metaplastic types (P < .001). The odds of having high-risk RS were lower for some HTs, including micropapillary, after multivariable adjustment (P < .05). The low number of estrogen receptor-positive medullary and metaplastic carcinomas tested had higher odds of having high-risk RS. In T1 and T2 tumors, when ductal, lobular, mixed, and other types combined were compared, the mortality was different.

CONCLUSIONS.—

This population-based study of RS in HTs showed high-risk RSs are identified in traditionally good prognostic subtypes. Micropapillary carcinoma has lower odds of high-risk RS even after multivariable adjustment.

Focus on Triple-Negative Breast Cancer: Potassium Channel Expression and Clinical Correlates

Despite improvements in early diagnosis and treatment, breast cancer is still a major health problem worldwide. Among breast cancer subtypes, the most challenging and harder to treat is represented by triple-negative molecular subtype. Due to its intrinsic features this subtype cannot be treated neither with hormonal therapy (since it does not express estrogen or progesterone receptors) nor with epidermal growth factor receptor 2 (HER2) inhibitors (as it does not express high levels of this protein). For these reasons, the standard of care for these patients is represented by a combination of surgery, radiation therapy and chemotherapy. In this scenario, searching for novel biomarkers that might help both in diagnosis and therapy is mandatory. In the last years, it was shown that different families of potassium channels are overexpressed in primary breast cancers. The altered ion channel expression may be useful for diagnostic and therapeutic purposes due to some peculiar characteristics of this class of molecules. Ion channels are defined as pore-forming transmembrane proteins regulating passive ion fluxes in the cells. Ion channels represent good potential markers since, being localized at the plasma membrane level, their detection and block with specific drugs and antibodies might be fast and tunable. This review focuses on triple-negative breast cancers and recapitulates the current knowledge about potassium channels' clinical relevance and their potential use in the clinical setting, for triple-negative breast cancer diagnosis and therapy.

Histological subtypes in triple negative breast cancer are associated with specific information on survival

Much research has focused on finding novel prognostic biomarkers for triple negative breast cancer (TNBC), whereas only scattered information about the relation between histopathological features and survival in TNBC is available. This study aims to explore the prognostic value of histological subtypes in TNBC. A multicenter retrospective TNBC cohort was established from five Dutch hospitals. All non-neoadjuvantly treated, stage I-III patients with estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 negative breast cancer diagnosed between 2006 and 2014 were included. Clinical and follow-up data (overall survival; OS, relapse free survival; RFS) were retrieved and a central histopathological review was performed. Of 597 patients included (median follow up 62.8 months, median age at diagnosis 56.0 years), 19.4% developed a recurrence. The most prevalent histological subtypes were carcinoma of no special type (NST) (88.4%), metaplastic carcinoma (4.4%) and lobular carcinoma (3.4%). Collectively, tumors of special type were associated with a worse RFS and OS compared to carcinoma NST (RFS HR 1.89; 95% CI 1.18-3.03; p = 0.008; OS HR 1.94; 95% CI 1.28-2.92; p = 0.002). Substantial differences in survival, however, were present between the different histological subtypes. In the presented TNBC cohort, special histological subtype was in general associated with less favorable survival. However, within the group of tumors of special type there were differences in survival between the different subtypes. Accurate histological examination can provide specific prognostic information that may potentially enable more personalized treatment and surveillance regimes for TNBC patients.

Bimodal age distribution at diagnosis in breast cancer persists across molecular and genomic classifications

PURPOSE

Female breast cancer demonstrates bimodal age frequency distribution patterns at diagnosis, interpretable as two main etiologic subtypes or groupings of tumors with shared risk factors. While RNA-based methods including PAM50 have identified well-established clinical subtypes, age distribution patterns at diagnosis as a proxy for etiologic subtype are not established for molecular and genomic tumor classifications.

METHODS

We evaluated smoothed age frequency distributions at diagnosis for Carolina Breast Cancer Study cases within immunohistochemistry-based and RNA-based expression categories. Akaike information criterion (AIC) values compared the fit of single density versus two-component mixture models. Two-component mixture models estimated the proportion of early-onset and late-onset categories by immunohistochemistry-based ER (n = 2860), and by RNA-based ESR1 and PAM50 subtype (n = 1965). PAM50 findings were validated using pooled publicly available data (n = 8103).

RESULTS

Breast cancers were best characterized by bimodal age distribution at diagnosis with incidence peaks near 45 and 65 years, regardless of molecular characteristics. However, proportional composition of early-onset and late-onset age distributions varied by molecular and genomic characteristics. Higher ER-protein and ESR1-RNA categories showed a greater proportion of late age-at-onset. Similarly, PAM50 subtypes showed a shifting age-at-onset distribution, with most pronounced early-onset and late-onset peaks found in Basal-like and Luminal A, respectively.

CONCLUSIONS

Bimodal age distribution at diagnosis was detected in the Carolina Breast Cancer Study, similar to national cancer registry data. Our data support two fundamental age-defined etiologic breast cancer subtypes that persist across molecular and genomic characteristics. Better criteria to distinguish etiologic subtypes could improve understanding of breast cancer etiology and contribute to prevention efforts.

Exploring Collagen Parameters in Pure Special Types of Invasive Breast Cancer

One of the promising tools to evaluate collagen in the extracellular matrix is the second-harmonic generation microscopy (SHG). This approach may shed light on the biological behavior of cancers and their taxonomy, but has not yet been applied to characterize collagen fibers in cases diagnosed as invasive breast carcinoma (BC) of histological special types (IBC-ST). Tissue sections from 99 patients with IBC-ST and 21 of invasive breast carcinoma of no special type (IBC-NST) were submitted to evaluation of collagen parameters by SHG. Tissue microarray was performed to evaluate immunohistochemical-based molecular subtype. In intratumoral areas, fSHG and bSHG (forward-SHG and backward-SHG) collagen parameters achieved their lowest values in mucinous, papillary and medullary carcinomas, whereas the highest values were found in classic invasive lobular and tubular carcinomas. Unsupervised hierarchical cluster analysis and minimal spanning tree using intratumoral collagen parameters allowed the identification of three main groups of breast cancer: group A (classic invasive lobular and tubular carcinomas); group B (IBC-NST, metaplastic, invasive apocrine and micropapillary carcinomas); and group C (medullary, mucinous and papillary carcinomas). Our findings provide further characterization of the tumor microenvironment of IBC-ST. This understanding may add information to build more consistent tumor categorization and to refine prognostication.

Molecular Classification of Breast Cancer

Breast cancer is a heterogeneous disease, observed traditionally by morphology and protein expression but, more recently with the advent of modern molecular technologies, at the genomic and transcriptomic level. This review describes the association between the different molecular subtypes with the histologic subtypes of breast cancer alongside some of their major genomic characteristics and illustrates how these subtypes may affect the appearance of tumors on imaging studies. The authors aim to show how molecular stratification can be used to augment traditional methods to improve our understanding of breast cancers and their clinical management.

Immunohistochemical Analysis of ER, PR, HER-2, CK 5/6, p63 and EGFR Antigen Expression in Medullary Breast Cancer

Aims and Background

Recent publications of breast cancer classification based on gene expression profile analyses indicate that medullary breast carcinomas (MBC) may be considered part of the basal-like carcinoma spectrum made up of ER-negative, PR-negative and HER-2-negative cells (“triple-negative phenotype”). On the other hand, there are also data showing that a proportion of MBC and atypical MBC (AMBC) is ER, PR and/or HER-2 positive. Therefore, we have decided to immunohistochemically analyze ER, PR, HER-2 and basal/myoepithelial markers CK5/6, p63 and EGFR expression in our archival paraffin-embedded MBC and AMBC samples from 48 patients.

Methods

Immunohistochemical evaluation of samples which were derived from patients operated on at our two hospitals between 1999 and 2005.

Results

Typical MBC was found in 39 patients and AMBC in 9 patients. The patients ranged in age from 32 to 84 years (median 55). Modified radical mastectomy with axillary dissection was performed in 30/48 patients (63%) while breast segmentectomy with axillary dissection was performed in 18/48 patients (37%). Metastases in axillary lymph nodes were observed in 15/48 patients (31%). ER positivity was present in 3/48 patients (6%), PR positivity in 8/48 (17%), and a positive HER-2 reaction was present in 14/48 patients (29%). CK 5/6 was positive in 20/48, p63 in 24/48 and EGFR in 8/48 patients. Adjuvant therapy was applied in all but 2 patients. Alive were 45/48 (94%) of patients. With the exception of PR expression, 39 patients with typical MBC and 9 patients with AMBC were comparable in the analyzed parameters. Positive HER-2 antigen expression in the analyzed sample was not found to be associated to a statistically significant degree with the MBC or AMBC histological tumor type, tumor size, axillary lymph node metastases, ER and PR status nor with patient survival.

Conclusions

The data from our study seem to be generally comparable with the relatively scarce published data on clinicopathological parameters of MBC and AMBC.

Breast Cancer Genetics for Plastic Surgeons

Multidisciplinary genetic clinics offer counseling and testing to those who meet criteria for familial breast cancer, and plastic surgeons become integral to this process when risk-reducing surgery and postmastectomy reconstruction are deemed appropriate. As reconstructive surgeons, it is important that plastic surgeons are aware of the risks and issues associated with the genetic variants that cause patients to present for prophylactic or therapeutic surgery.

"Triple negative breast cancer": Translational research and the (re)assembling of diseases in post-genomic medicine

The paper examines the debate about the nature and status of "Triple-negative breast cancer", a controversial biomedical entity whose existence illustrates a number of features of post-genomic translational research. The emergence of TNBC is intimately linked to the rise of molecular oncology, and, more generally, to the changing configuration of the life sciences at the turn of the new century. An unprecedented degree of integration of biological and clinical practices has led to the proliferation of bio-clinical entities emerging from translational research. These translations take place between platforms rather than between clinical and laboratory settings. The complexity and heterogeneity of TNBC, its epistemic and technical, biological and clinical dualities, result from its multiple instantiations via different platforms, and from the uneven distribution of biological materials, techniques, and objects across clinical research settings. The fact that TNBC comes in multiple forms, some of which seem to be incompatible or, at least, only partially overlapping, appears to be less a threat to the whole endeavor, than an aspect of an ongoing translational research project. Discussions of translational research that rest on a distinction between basic research and its applications fail to capture the dynamics of this new domain of activity, insofar as application is built-in from the very beginning in the bio-clinical entities that emerge from the translational research domain.

Clinicopathologic characteristics of typical medullary breast carcinoma: a retrospective study of 117 cases

PURPOSE

This study analyzed the clinicopathologic characteristics of typical medullary breast carcinoma (TMBC) in a cohort of Chinese patients.

METHODS

We conducted a retrospective review of clinical data including general information, pathologic results, treatment regimens, and patient survival in cases of TMBC diagnosed between February 2004 and April 2011.

RESULTS

A total of 117 patients were enrolled, with a median age of 52 years (range, 28∼92 years). Stage I and II disease accounted for 31.6% and 61.6% of the cases, respectively. Hormonal receptor negative disease (estrogen receptor negative, 68.4%; progestogen receptor negative, 86.3%) was more prevalent in this population. Human epidermal growth factor receptor-2 (HER-2) positivity was 20.5%, while equivocal and HER-2 negative cases represented 16.2% and 63.2% of the cohort. The triple-negative, luminal, and HER-2 overexpressing subtypes constituted 44.4%, 31.6%, and 15.4% of the cases, respectively. The various TMBC subtypes showed no differences regarding tumor size, rates of lymph node(s) metastasis, TNM staging, treatment regimens, and 2-year recurrence rates. However, patients with triple-negative disease were more likely to be younger, when compared to those with luminal disease (P = 0.002). At a median follow-up of 56 months (range, 2-112 months), the 2-year disease-free survival and overall survival rates were 99.1% and 98.2%, respectively.

CONCLUSION

Early stage disease dominated the study cohort, and at two years after surgery, recurrence was extremely low. The heterogeneity of molecular subtypes was clearly shown, and no apparent differences were found among the clinicopathologic characteristics of the triple-negative, luminal, and HER-2 overexpressing subtypes.

Squamous/epidermoid differentiation in normal breast and salivary gland tissues and their corresponding tumors originate from p63/K5/14-positive progenitor cells

A small group of tumors of breast and salivary glands contains squamous/epidermoid elements as a constitutive feature (e.g., squamous carcinoma, syringomatous tumors, and mucoepidermoid carcinoma). Other tumors (e.g., pleomorphic adenoma, adenomyoepithelial tumors, and adenoid cystic carcinoma) may show occasionally squamous differentiation. Furthermore, squamous metaplasia may be observed in non-neoplastic breast and salivary tissues. However, the histogenesis of these squamous differentiations is far from being understood. Based on our earlier in situ triple immunofluorescence and quantitative reverse transcription (RT)-PCR experiments for basal keratins K5/14 and p63 as well as for glandular keratins (K7/K8/18), squamous keratins (K10 and K13), and myoepithelial lineage markers (smooth muscle actin, SMA), we here traced the squamous/epidermoid differentiation lineage of 60 tumors of the breast and/or salivary glands, cultured tumor cells of 2 tumors, and of 7 squamous metaplasias of non-neoplastic breast and salivary tissues. Our results indicate that both the neoplastic lesions as well as the non-neoplastic squamous metaplasia contain p63/K5/14+ cells that differentiate toward K10/13+ squamous cells. Thus, cells with squamous/epidermoid differentiation undergo a transition from its original p63/K5/14+ precursor state to K10/13+ squamous lineage state, which can be pictured by triple-immunofluorescence experiments. Given the immunophenotypic similarity of p63/K5/14+ tumor cells to their physiological p63/K5/14+ counterparts in normal breast and salivary duct epithelium, we suggest that these cells provide an important histogenetic key to understanding the pathogenesis of squamous differentiation both in normal breast/salivary gland tissues and their corresponding tumors.

Clinicopathological features and prognosis of triple negative breast cancer in Kuwait: A comparative/perspective analysis

AIM

The aim of this study was to determine the incidence of TNBC in Kuwait, to analyze the clinicopathologic features and prognosis of this type of breast cancer, and compare it with reports from other regions of the world.

BACKGROUND

Triple negative breast cancer (TNBC) is defined as a subtype that is negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). There is a growing evidence of the heterogeneity of such entity on the molecular level that may cause discrete outcomes.

METHODS

We analyzed the clinicopathologic features of 363 TNBC cases which were diagnosed in Kuwait from July 1999 to June 2009. The disease-free survival (DFS) and overall survival (OS) were analyzed by Kaplan-Meier method. Comparison was done with reports from USA, Europe, Middle and Far East.

RESULTS

Among 2986 patients diagnosed with breast cancer in Kuwait, 363 patients (12.2%) were TNBC. The median age was 48 years, 57.2% had lymph nodes (LN) metastasis, 56.9% were of grade III tumor and 41.9% had stage II disease. 81% developed recurrences and 75% of deaths occurred by 2.5 years after treatment. There is marked variation of clinicopathologic features according to country of patients' cohort.

CONCLUSION

The incidence of TNBC in our study is similar to other studies. TNBC patients showed an early major recurrence surge peaking at approximately year 2.5. Regional variation of clinicopathologic features indicates a need for molecular studies to define underlying molecular features and its impact on survival.

Calretinin expression in high-grade invasive ductal carcinoma of the breast is associated with basal-like subtype and unfavorable prognosis

Calretinin, a calcium-binding protein, is a widely used marker for mesothelial differentiation. There is accumulating evidence of calretinin expression in epithelial and mesenchymal malignancies, as well. The objectives of this study were to (1) further delineate the expression of calretinin in grade 3 breast carcinomas in the context of molecular subtypes and (2) identify the impact of calretinin expression on overall and disease-free survival. On the basis of immunohistochemical expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER2), cytokeratin 5/6, and epidermal growth factor receptor, 214 grade 3 invasive ductal carcinomas were stratified into 36 luminal A, 63 luminal B, 24 HER2 positive, 81 basal-like (including 13 metaplastic carcinomas), and 10 unclassified. Tissue microarrays were analyzed for immunohistochemical expression of calretinin. High-level calretinin expression was identified in a significant proportion of basal-like (54.3%), HER2 (33.3%), and unclassified (30%) tumors. In contrast, luminal A and B subtypes demonstrated high-level calretinin expression in only 11.1% and 12.7%, respectively (P < .0001). Within the basal-like group, 38.5% of the metaplastic carcinomas demonstrated high-level expression, associated predominantly with the epithelial component and squamous metaplasia. High-level calretinin expression was strongly associated with decreased overall survival in the entire cohort of grade 3 cancer (P = .0096) and in the basal-like group (P = .039). Multivariate analysis revealed that both tumor stage and high-level calretinin expression were independent predictors of overall survival (P = .0002 and P = .0023, respectively). In conclusion, high-level calretinin expression is most common in grade 3 tumors with a basal-like phenotype and is associated with poor overall survival.

[Triple-negative breast cancer: histoclinical and molecular features, therapeutic management and perspectives]

Triple-negative breast cancer (TNBC), as defined by the absence of estrogen and progesterone receptor expression, as well as the lack of HER2 overexpression/amplification, corresponds to 15% of breast cancer and represents an aggressive form of the disease. TNBC are frequently confounded with basal subtype in the molecular classification of breast cancer and also share some similarities with BRCA1-mutated tumors. Epidemiological and clinical characteristics are distinct from other subtypes, including a younger age at diagnosis, a higher risk of relapse in spite of increased chemosensitivity, and a higher incidence of lung and brain metastatic relapses. Conventional cytotoxics remain the mainstay of current systemic management but recent evaluation of more targeted therapeutics, including specific cytotoxics (such as the use of platinum salts), PARP and EGFR inhibition, and antiangiogenics have been performed, providing contrasted but rather disappointing results. Recent data indicate that TNBC represent a heterogeneous entity composed of multiple and distinct molecular subtypes, which should deserve specific targeted therapeutics.

In vitro and in vivo evaluation of novel anticancer agents in triple negative breast cancer models

Triple negative breast cancer (TNBC) is subtype of breast disease devoid of the estrogen, progesterone, and Her2/neu receptors which are targets for pharmacological intervention. There is a need for novel anti-breast cancer agents that target TNBC. Therefore, novel isochalcone DJ52 was evaluated using the alamar blue dye exclusion assay, the luciferase colony assay, and xenograft models to determine its efficacy and potency. DJ52 significantly decreased proliferation of cells measured by using the alamar blue dye method and produced IC50 values of DJ52, DJ56, and DJ82 at 10-6M, 10-5M, and 10-5M, respectively. In vivo studies were conducted by injecting MDA-MB-231 cells into SCID mice to determine tumor regression was measured over 20 days. DJ52 at 50 mg/kg caused significant decrease in tumor volume (p value <.05) by nearly 50% compared with the control with vehicle alone. These data suggest that DJ52 has merit for further evaluation as a novel anticancer agent.

Prediction of BRCA1 germ-line mutation status in patients with breast cancer using histoprognosis grade, MS110, Lys27H3, vimentin, and KI67

Family structure, lack of reliable information, cost, and delay are usual concerns when deciding to perform BRCA analyses. Testing breast cancer tissues with four antibodies (MS110, lys27H3, vimentin, and KI67) in addition to grade evaluation enabled us to rapidly select patients for genetic testing identification. We constituted an initial breast cancer tissue microarray, considered as a learning set, comprising 27 BRCA1 and 81 sporadic tumors. A second independent validation set of 28 BRCA1 tumors was matched to 28 sporadic tumors using the same original conditions. We investigated morphological parameters and 21 markers by immunohistochemistry. A logistic regression model was used to select the minimal number of markers providing the best model to predict BRCA1 status. The model was applied to the validation set to estimate specificity and sensibility. In the initial set, univariate analyses identified 11 markers significantly associated with BRCA1 status. Then, the best multivariate model comprised only grade 3, MS110, Lys27H3, vimentin, and KI67. When applied to the validation set, BRCA1 tumors were correctly classified with a sensitivity of 83% and a specificity of 81%. The performance of this model was superior when compared to other profiles. This study offers a new rapid and cost-effective method for the prescreening of patients at high risk of being BRCA1 mutation carriers, to guide genetic testing, and finally to provide appropriate preventive measures, advice, and treatments including targeted therapy to patients and their families.

Molecular pathology of breast cancer: what a pathologist needs to know

Pathologists are now more than ever "diagnostic oncologists" and serve a critical role as clinical consultants on the biology of disease. In the last decade and a half, molecular information has transformed our thinking about the biologic diversity of breast cancers and redirected the way clinical treatment decisions are made. A basic understanding of the current molecular classification of breast cancers and the biologic pathways from precursors to invasive disease is key to both informing diagnostic practice and serving as clinical consultants. In addition, both single-marker and panel-based molecular tests are currently being utilized in breast cancer tissue to predict the benefit of specific therapies such as HER2-targeted biologic therapy and chemotherapy. Familiarity with the current issues involving these molecular tests as well as the pathologist's role in ensuring appropriate tissue handling, tissue selection, and results interpretation and correlation are paramount to providing optimal patient care.

Prognosis of medullary breast cancer: analysis of 13 International Breast Cancer Study Group (IBCSG) trials

BACKGROUND

To evaluate whether medullary breast cancer has a better prognosis compared with invasive ductal tumors.

METHODS

Among 12,409 patients, 127 were recorded as invasive medullary tumors and 8096 invasive ductal tumors. Medullary and ductal invasive tumors were compared with regard to stage, age at diagnosis, grade, hormone receptor status, peritumoral vascular invasion, and local and systemic treatment. Pattern of relapse, distant recurrence-free interval (DRFI), and overall survival (OS) were determined for both histological groups. Two cohorts were investigated: a full cohort including the pathologist-determined medullary histology without regard to any other tumor features and a cohort restricted to patients with ER-negative grade 3 tumors.

RESULTS

Fourteen-year DRFI and OS percents for medullary tumors (n = 127) and invasive ductal tumors (n = 8096) of the full cohort were 76% and 64% [hazard ratio (HR) 0.52, P = 0.0005] and 66% and 57% (HR = 0.75, P = 0.03), respectively. For the restricted cohort, 14-year DRFI and OS percents for the medullary (n = 47) and invasive ductal tumors (n = 1407) were 89% and 63% (HR 0.24, P = 0.002) and 74% and 54% (HR = 0.55, P = 0.01), respectively. Competing risk analysis for DRFI favored medullary tumors (HR medullary/ductal = 0.32; 95% confidence interval = 0.13-0.78, P = 0.01).

CONCLUSION

Medullary tumors have a favorable prognosis compared with invasive ductal tumors.

A comprehensive morphological study for basal-like breast carcinomas with comparison to nonbasal-like carcinomas

Background

Breast carcinomas can be classified into five subtypes based on gene expression profiling or immunohistochemical characteristics. Among these subtypes, basal-like breast carcinomas (BLBCs) are one of the most studied group, due to their poor prognosis. The aim of this study was to investigate the prevalance, morphological and immunohistochemical features of BLBCs, in Turkish population.

Methods

Five hundred invasive breast carcinomas were reviewed for several morphological features and immunostained for oestrogen and progesterone receptors, c-ERB-B2, cytokeratin5/6, cytokeratin14, vimentin and epidermal growth factor receptor (EGFR). Basal-like breast carcinoma was defined as a triple negative tumor with cytokeratin5/6 and/or EGFR positive.

Results

The prevalance of BLBC was 9.6%. All medullary carcinomas and 55.6% of metaplastic carcinomas showed basal-like immunophenotype. Patients with BLBC were younger (p=0.04) and had higher-grade tumors (p<0.0001). Morphologic features associated with BLBC included increased mitosis, nuclear pleomorphism, presence of geographic and/or central necrosis, pushing margin of invasion and stromal lymphocytic response (p<0.0001). Presence of prominent nucleoli and vesicular nuclear chromatin were the cytological features correlated with basal-like phenotype (p<0.0001). On multivariate analyses, BLBCs were associated with high mitotic number (p<0.0001), the presence of vesicular chromatin (p=0.004), high tubular grade (p=0.011), lymphocytic response (p=0.031) and the absence of carcinoma insitu (p=0.039). Vimentin was positive in 53.2% of BLBCs, while cytokeratin14 was less frequently expressed (27.7%).

Conclusions

BLBCs have some distinctive, but not pathognomonical, morphological features. Paying attention to these features and adding cytokeratin14 and vimentin to the immunohistochemical panel can help the definitive diagnosis of BLBCs.

Virtual slide

Http://www.diagnosticpathology.diagnomx.eu/vs/5962175467857400

Risk factors for uncommon histologic subtypes of breast cancer using centralized pathology review in the Breast Cancer Family Registry

Epidemiologic studies of histologic types of breast cancer including mucinous, medullary, and tubular carcinomas have primarily relied on International Classification of Diseases-Oncology (ICD-O) codes assigned by local pathologists to define histology. Using data from the Breast Cancer Family Registry (BCFR), we compared histologic agreement between centralized BCFR pathology review and ICD-O codes available from local tumor registries among 3,260 breast cancer cases. Agreement was low to moderate for less common histologies; for example, only 55 and 26 % of cases classified as mucinous and medullary, respectively, by centralized review were similarly classified using ICD-O coding. We then evaluated risk factors for each histologic subtype by comparing each histologic case group defined by centralized review with a common set of 2,997 population-based controls using polytomous logistic regression. Parity [odds ratio (OR) = 0.4, 95 % confidence interval (95 % CI): 0.2-0.9, for parous vs. nulliparous], age at menarche (OR = 0.5, 95 % CI: 0.3-0.9, for age ≥13 vs. ≤11), and use of oral contraceptives (OCs) (OR = 0.5, 95 % CI: 0.2-0.8, OC use >5 years vs. never) were associated with mucinous carcinoma (N = 92 cases). Body mass index (BMI) (OR = 1.05, 95 % CI: 1.0-1.1, per unit of BMI) and high parity (OR = 2.6, 95 % CI: 1.1-6.0 for ≥3 live births vs. nulliparous) were associated with medullary carcinoma (N = 90 cases). We did not find any associations between breast cancer risk factors and tubular carcinoma (N = 86 cases). Relative risk estimates from analyses using ICD-O classifications of histology, rather than centralized review, resulted in attenuated, and/or more imprecise, associations. These findings suggest risk factor heterogeneity across breast cancer tumor histologies, and demonstrate the value of centralized pathology review for classifying rarer tumor types.

Molecular classification of breast carcinomas with particular emphasis on "basal-like" carcinoma: a critical review

During the last 11 years, 5 molecular subtypes of breast carcinoma (luminal A, luminal B, Her2-positive, basal-like, and normal breast-like) have been characterized and intensively studied. As genomic research evolves, further subtypes of breast cancers into new "molecular entities" are expected to occur. For example, a new and rare breast cancer subtype, known as claudin-low, has been recently found in human carcinomas and in breast cancer cell lines. There is no doubt that global gene expression analyses using high-throughput biotechnologies have drastically improved our understanding of breast cancer as a heterogeneous disease. The main question is, however, whether new molecular techniques such as gene expression profiling (or signature) should be regarded as the gold standard for identifying breast cancer subtypes. A critical review of the literature clearly shows major problems with current molecular techniques and classification including poor definitions, lack of reproducibility, and lack of quality control. Therefore, the current molecular approaches cannot be incorporated into routine clinical practice and treatment decision making as they are immature or even can be misleading. This review particularly focuses on the "basal-like" breast cancer subtype that represents one of the most popular breast cancer "entities". It critically shows major problems and misconceptions with and about this subtype and challenges the common claim that it represents a "distinct entity". It concludes that the term "basal-like" is misleading and states that there is no evidence that expression of basal-type cytokeratins in a given breast cancer, regardless of other established prognostic factors, does have any impact on clinical outcome.

Dissecting the heterogeneity of triple-negative breast cancer

Triple-negative breast cancer (TNBC) accounts for 15% to 20% of breast cancers. It is a heterogeneous disease, not only on the molecular level, but also on the pathologic and clinical levels. TNBC is associated with a significantly higher probability of relapse and poorer overall survival in the first few years after diagnosis when compared with other breast cancer subtypes. This is observed despite its usual high sensitivity to chemotherapy. In the advanced setting, responses observed with chemotherapy lack durability. Early-stage clinical studies suggested impressive potential when a poly (ADP-ribose) polymerase (PARP) inhibitor is given for the treatment of advanced TNBC with BRCA gene dysfunction. The molecular complexity of TNBC has led to proposed subclassifications, which will be of great value for the development of targeted therapies. In this review, we discuss the biology of TNBC at the pathologic and the molecular levels. We also elaborate on the role of systemic therapies and the results of the first phase III clinical trial evaluating the addition of iniparib, a novel investigational anticancer agent that does not possess characteristics typical of the PARP inhibitor class, in combination with chemotherapy in advanced TNBC.

Basal breast cancer: a complex and deadly molecular subtype

During the last decade, gene expression profiling of breast cancer has revealed the existence of five molecular subtypes and allowed the establishment of a new classification. The basal subtype, which represents 15-25% of cases, is characterized by an expression profile similar to that of myoepithelial normal mammary cells. Basal tumors are frequently assimilated to triple-negative (TN) breast cancers. They display epidemiological and clinico-pathological features distinct from other subtypes. Their pattern of relapse is characterized by frequent and early relapses and visceral locations. Despite a relative sensitivity to chemotherapy, the prognosis is poor. Recent characterization of their molecular features, such as the dysfunction of the BRCA1 pathway or the frequent expression of EGFR, provides opportunities for optimizing the systemic treatment. Several clinical trials dedicated to basal or TN tumors are testing cytotoxic agents and/or molecularly targeted therapies. This review summarizes the current state of knowledge of this aggressive and hard-to-treat subtype of breast cancer.

High expression of indoleamine 2,3-dioxygenase in the tumour is associated with medullary features and favourable outcome in basal-like breast carcinoma

Medullary breast cancer (MBC) is a basal-like breast carcinoma (BLBC) with a favourable outcome, whereas nonmedullary BLBC has a poor prognosis. Tumour infiltrating lymphocytes (TILs) are present in both MBC and BLBC. We hypothesized that the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) could modulate the TILs effects among these tumours and explain their different outcomes. The amount of TILs and IDO expression were analysed using immunohistochemistry (IHC) in 155 BC cases including MBC (n = 17), atypical MBC (n = 13) and non-MBC (n = 125). Messenger RNA expression of the INDO gene, which encodes IDO, was measured in 262 cases from our institution. INDO mRNA expression and histoclinical data of 1,487 BC cases were collected from public databases. IDO immunostaining was present in both neoplastic and stromal cells in 100% of MBC and was associated with histological medullary features among non-MBC cases. There was a significant correlation between IDO positivity and TIL amounts. In our series including mostly grade-3 BC, IDO immunostaining was the most significant marker (p = 0.02) associated with better survival in multivariate analysis. Among our 262 analysed BC cases, INDO mRNA showed significant overexpression in BLBC as compared to luminal A tumours, and in MBC as compared to basal-like non-MBC. In the pooled series of 1,749 BC cases, INDO mRNA was overexpressed in BLBC and was the most significant predictor of better survival in this subtype using multivariate analysis (p = 0.0024). In conclusion, high IDO expression is associated with morphological medullary features and has an independent favourable prognostic value in BLBC.

Expression of MAGE-A and NY-ESO-1 cancer/testis antigens in medullary breast cancer: retrospective immunohistochemical study

Aim

To immunohistochemically evaluate the expression of MAGE-A1, MAGE-A, and NY-ESO-1 cancer/testis (C/T) tumor antigens in medullary breast cancer (MBC) tumor samples and to analyze it in relation to the clinicopathological features.

Methods

This retrospective study included samples from 49 patients: 40 with typical MBC and 9 with atypical MBC. Tumor specimens were obtained from patients operated on in the University Hospital for Tumors and the Sisters of Mercy University Hospital, Zagreb, Croatia, from 1999 to 2005. Standard immunohistochemistry was used on archival paraffin-embedded MBC tissues.

Results

MAGE-A1, MAGE-A, and NY-ESO-1 antigens were expressed in 33% (16/49), 33% (16/49), and 22% (11/49) of patients, respectively. No difference between the groups with and without C/T tumor antigen expression in age at diagnosis, tumor size, axillary lymph node metastasis, adjuvant therapy, and HER-2 expression was identified. Significantly more patients died in the MAGE-A-positive group than in the MAGE-A-negative group (P = 0.010), whereas a borderline significance was found between MAGE-A1-positive and the MAGE-A1-negative group (P = 0.079) and between NY-ESO-1-positive and NY-ESO-1-negative group (P = 0.117). Overall survival, as evaluated by the Kaplan-Meier curves, was lower in MAGE-A1- (P = 0.031), MAGE-A- (P = 0.004), NY-ESO-1-positive groups (P = 0.077).

Conclusion

Expression of C/T antigens may represent a marker of potential prognostic relevance in MBC.

Triple-Negative Breast Cancer: Clinical and Histological Correlations

SUMMARY: Triple-negative breast cancer (TNBC) is characterized by the lack of estrogen and progesterone receptors and the lack of HER2 expression or amplification. Much interest has recently been focused on these triple-negative (TN) subtypes because they may be aggressive and are more likely to recur and metastasize than other subtypes of breast cancer. TNBC accounts for approximately 10-24% of all breast cancer cases, and typically it occurs in younger patients and in patients with BRCA1 mutation. There is a substantial heterogeneity of TNBCs both at the morphological and the molecular level, but there are also common features, such as low tumor grade and accelerated tumor proliferation. Morphologically, TNBC may present as invasive ductal, metaplastic, medullary, apocrine, or other types. Molecularly, they are most frequently associated with a basal phenotype, but there is a distinct subgroup of cancers that are not of basal type and belong to the claudin-low or molecular-apocrine type. The basal phenotype is frequently associated with the loss of BRCA1.

Basal phenotype breast cancer: implications for treatment and prognosis

Breast cancer is the most common malignancy in females. The origins and biology of breast carcinomas remain unclear. Cellular and molecular heterogeneity results in different distinct groups of tumors with different clinical behavior and prognosis. Gene expression profiling has delineated five molecular subtypes based on similarities in gene expression: luminal A, luminal B, HER2 overexpressing, normal-like and basal-like. Basal-like breast cancer (BLBC) lacks estrogen receptor, progesterone receptor and HER2 expression, and comprises myoepithelial cells. Specific features include high proliferative rate, rapid growth, early recurrence and decreased overall survival. BLBC is associated with ductal carcinoma in situ, BRCA1 mutation, brain and lung metastasis, and negative axillary lymph nodes. Currently, chemotherapy is the only therapeutic choice, but demonstrates poor outcomes. There is an overlap in definition between triple-negative breast cancer and BLBC due to the triple-negative profile of BLBC. Despite the molecular and clinical similarities, the two subtypes respond differently to neoadjuvant therapy. Although particular morphologic, genetic and clinical features of BLBC have been identified, a variety of definitions among studies accounts for the contradictory results reported. In this article the molecular morphological and histopathological profile, the clinical behavior and the therapeutic options of BLBC are presented, with emphasis on the discordant findings among studies.

Management options in triple-negative breast cancer

Notorious for its poor prognosis and aggressive nature, triple-negative breast cancer (TNBC) is a heterogeneous disease entity. The nature of its biological specificity, which is similar to basal-like cancers, tumors arising in BRCA1 mutation carriers, and claudin-low cancers, is currently being explored in hopes of finding the targets for novel biologics and chemotherapeutic agents. In this review, we aim to give a broad overview of the disease's nomenclature and epidemiology, as well as the basic mechanisms of emerging targeted therapies and their performance in clinical trials to date.

Clinical significance of morphologic characteristics in triple negative breast cancer

Purpose

No clinically useful target molecule has been identified for triple-negative (TN) breast cancer, i.e., estrogen receptor-negative, progesterone receptor-negative, human epidermal growth factor receptor-2-negative phenotype, and its prognosis is poor. The aim of this study is to clarify the clinical and pathologic characteristics of triple negative breast cancer (TNBC).

Methods

The study subjects, 87 women with TNBC, were a subset of patients operated at Kosin University Gospel Hospital from January 2000 to December 2005. We examined pathologic characteristics such as tumor necrosis, infiltrating border, lymphocytic infiltration, prominent nucleoli in TNBC. And we studied the correlation between TNBC and several factors related to pathologic morphology. Chi-squared tests were used for statistical analysis. Kaplan-Meier estimates are presented for the survival function, and differences in survival were analyzed using the log rank test.

Results

Tumor necrosis was found in 51 patients (58.3%) in TNBC. And infiltrating border was found in 71 patients (81.0%). Also continuous lymphocytic distribution and prominent nucleoli was found in 31 patients (35.7%), 52 patients (59.7%), respectively. No association was detected between pathologic characteristics and other biological markers. Patients with tumor necrosis positive for TNBC didn't show shorter disease-free survival (P = 0.4490) or overall survival (P = 0.979) than patients without tumor necrosis.

Conclusion

These findings suggest that pathologic characteristics cannot be used to classify triple-negative breast cancer into only two subtypes with differing prognoses. But because our study is small size study, more abundant patients' dates will be needed to evaluate the morphologic characteristics' predictive role.

Basal-like and triple-negative breast cancers: a critical review with an emphasis on the implications for pathologists and oncologists

Breast cancer is a heterogeneous disease encompassing a variety of entities with distinct morphological features and clinical behaviors. Although morphology is often associated with the pattern of molecular aberrations in breast cancers, it is also clear that tumors of the same histological type show remarkably different clinical behavior. This is particularly true for 'basal-like cancer', which is an entity defined using gene expression analysis. The purpose of this article was to review the current state of knowledge of basal-like breast cancers, to discuss the relationship between basal-like and triple-negative breast cancers, and to clarify practical implications of these diagnoses for pathologists and oncologists.

P-cadherin expression as a prognostic biomarker in a 3992 case tissue microarray series of breast cancer

P-cadherin is a calcium-dependent cell-cell adhesion glycoprotein. P-cadherin expression is restricted to the myoepithelial cells in normal breast tissue, and aberrant staining has also been described in invasive tumors. Several small studies have reported P-cadherin as a marker of poor outcome in breast cancer patients but its prognostic significance in relation to other variables has not been established in a large series of breast cancers. A tissue microarray was constructed from 3992 cases of invasive breast carcinoma, and P-cadherin expression was evaluated using immunohistochemistry. Median follow-up was 12.5 years. The immunohistochemistry-based definitions of cancer subtypes were luminal (ER+ or PR+/HER2-), luminal/HER2+ (ER+ or PR+/HER2+), HER2+ (ER-/PR-/HER2+), and basal (ER-/PR-/HER2-/CK5/6+ or EGFR+). Clinical covariate and biomarker associations were assessed using contingency tables, and Pearson's χ(2) or Fisher's exact test. Survival associations were assessed using Kaplan-Meier plots, logrank and Breslow tests, and Cox proportional hazards regression analysis. P-cadherin was expressed in 34.8% (1290/3710, 50% cut point) of cases. P-cadherin staining was strongly associated with HER2+ and basal carcinoma subtypes (P<0.0005). P-cadherin-positive patients showed significantly poorer short-term (0-10 years) overall survival, disease-specific survival, distant relapse-free interval, and locoregional relapse-free interval in univariable models (P<0.05). In multivariable Cox models containing standard clinical covariates and cancer subtypes, P-cadherin did not show independent prognostic value. P-cadherin expression was positively associated with histological grade, chemotherapy, Ki-67, EGFR, CK5/6, p53, YB-1, and HER2 expression (P<0.002), and negatively associated with age at diagnosis, ER, PR, and Bcl-2 expression (P<0.0005). This study shows the value of P-cadherin as a marker of poor prognosis. The large sample size of this series clarifies contradictory findings of many smaller studies. P-cadherin positivity is associated with high-grade tumor subtypes and well-established markers of poor prognosis, and may represent a promising antibody therapeutic target.

Triple negative breast cancer: unmet medical needs

Triple negative breast cancer (TNBC) is an aggressive clinical phenotype characterized by lack of expression (or minimal expression) of estrogen receptor (ER) and progesterone receptor (PR) as well as an absence of human epidermal growth factor receptor-2 (HER2) overexpression. It shows substantial overlap with basal-type and BRCA1-related breast cancers, both of which also have aggressive clinical courses. However, this overlap is not complete, and the expression of ER, PR, and HER2 has been noted in basal-like tumors. TNBC also includes the normal-like subtype, and not all patients with TNBC harbor BRCA1 mutations. Because of its expression profile, TNBC is not amenable to treatment with hormone therapy or the anti-HER2 monoclonal antibody trastuzumab, and systemic treatment options are currently limited to cytotoxic chemotherapy. Overall survival, whether in early-stage or advanced disease, is poor compared with that in patients who have other phenotypes. A number of targeted approaches to TNBC are undergoing clinical evaluation, including the use of agents with poly(ADP-ribose) polymerase inhibitory properties such as iniparib (the United States Adopted Name for the investigational agent BSI-201), olaparib (AZD2281), and veliparib (ABT-888), antiangiogenic agents such as bevacizumab and sunitinib, and epidermal growth factor receptor blockers such as cetuximab and erlotinib. Encouraging results with some of these agents have been reported, thereby offering the promise for improved outcomes in patients with TNBC. The clinical characteristics of TNBC and clinical experience to date with novel targeted agents under development for this aggressive phenotype is reviewed.

Histopathological subclassification of triple negative breast cancer using prognostic scoring system: five variables as candidates

We attempted to subclassify triple negative breast cancer (TNBC) cases into subgroups according to clinical outcome or prognosis of TNBC patients using archival specimens. We analyzed 102 Japanese cases of invasive TNBC who underwent surgery between January 1998 and December 2007. The clinicopathological factors and clinical information were retrospectively retrieved from reviewing the charts of the patients. Immunohistochemical staining was performed for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor 1 (EGFR1), CK5/6, CK14, Ki-67, and CD31 for microvessel density (MVD). Median follow-up time of the patients was 68.5 months. Multivariable analysis demonstrated that pathologic node status was the most significantly associated with relapse-free survival (RFS) and breast cancer-specific survival (BCSS) of these patients. Pathological tumor size, basal-like type, Ki-67 labeling index (LI) and MVD were also independently associated with RFS and BCSS. Based on these results, we devised the risk score system reflecting hazard ratios of these prognostic factors above. With this system, TNBC patients in this study were classified into three subgroups (low-risk group: score 0-3, intermediate-risk group: score 4-7 and high-risk group: score 8-10). The significant difference of RFS and BCSS was detected among these three different subgroups of the patients (p < 0.05). We propose the risk score system, which incorporated pathologic nodal status, size of the primary tumor, the presence or absence of basal-like features, Ki-67 LI, and MVD in order to predict postoperative clinical course of the Japanese TNBC patients.

Clinical proteomics of breast cancer

Despite the lifetimes that increased in breast cancers due to the the early screening programs and new therapeutic strategies, many cases still are being lost due to the metastatic relapses. For this reason, new approaches such as the proteomic techniques have currently become the prime objectives of breast cancer researches. Various omic-based techniques have been applied with increasing success to the molecular characterisation of breast tumours, which have resulted in a more detailed classification scheme and have produced clinical diagnostic tests that have been applied to both the prognosis and the prediction of outcome to the treatment. Implementation of the proteomics-based techniques is also seen as crucial if we are to develop a systems biology approach in the discovery of biomarkers of the early diagnosis, prognosis and prediction of the outcome of the breast cancer therapies. In this review, we discuss the studies that have been conducted thus far, for the discovery of diagnostic, prognostic and predictive biomarkers, and evaluate the potential of the discriminating proteins identified in this research for clinical use as breast cancer biomarkers.

Distinguishing medullary carcinoma of the breast from high-grade hormone receptor-negative invasive ductal carcinoma: an immunohistochemical approach

AIMS

Medullary carcinomas (MCs) represent a rare breast cancer subtype associated with a rather favourable prognosis compared with invasive ductal carcinomas (IDCs). Due to histopathological overlap, MCs are frequently misclassified as high-grade IDCs, potentially leading to overtreatment of MCs. Our aim was to establish novel diagnostic markers distinguishing MCs from hormone receptor-negative high-grade IDCs.

METHODS AND RESULTS

Sixty-one MCs and 133 hormone receptor-negative IDCs were analysed in a comparative immunohistochemical study. Applied markers included a comprehensive panel of cytokeratins (CKs), vimentin, smooth muscle actin (SMA), p63, p53, cell adhesion molecules [N-CAM (CD56), syndecan-1 (CD138), E-cadherin and P-cadherin] and development associated transcription factors (AP-2 alpha, AP-2 gamma). A significantly higher proportion of IDCs displayed increased expression of CK7, AP-2 alpha and HER2 in contrast to MCs (CK7: 91% of IDCs versus 77% of MCs; AP-2 alpha: 77% versus 57%; and HER2: 26% versus 7%, each P < 0.01). Vice versa, MCs were slightly more frequently positive for SMA and vimentin (P > 0.05).

CONCLUSIONS

Hormone receptor-negative high-grade IDCs are significantly associated with luminal differentiation, Her2 and AP-2 alpha overexpression, whereas MCs tend to display myoepithelial features. Markers analysed in this study are of diagnostic value regarding the differential diagnosis of MCs.

Histological features of medullary carcinoma and prognosis in triple-negative basal-like carcinomas of the breast

Medullary carcinomas have a better prognosis than other grade 3 mammary carcinomas, but they typically show basal-like biological features, which are associated with a poor prognosis. In this study we examined the associations and prognostic relevance of medullary histological features in a series of 165 invasive carcinomas with a basal-like phenotype: triple-negative (oestrogen receptor, progesterone receptor, HER2) and expressing at least one basal marker (CK5/6, CK14, CK17 or EGFR). The following histological features were associated with each other: prominent inflammation, anastomosing sheets, absence of fibrosis, absence of infiltrative margin and absence of gland formation. Prominent inflammation and anastomosing sheets in at least 30% of the tumour were associated with a better prognosis on univariate analysis. The combination of these two features (a simplified definition of medullary-like type) was present in 17% of tumours and was an independent prognostic factor on multivariate analysis. This simplified definition had good inter-observer reproducibility (κ=0.61) and is worthy of more detailed assessment in an unselected group of mammary carcinomas. A fibrotic focus was present in 36% of carcinomas. Only 3% of tumours with a fibrotic focus had features of medullary-like carcinomas. Fibrotic focus of greater than 30% of the tumour was associated with a poor prognosis. This study emphasizes the heterogeneity of morphology and behaviour of triple-negative basal-like carcinomas.

Triple-negative breast cancer: disease entity or title of convenience?

This Review outlines the understanding and management of triple-negative breast cancer (TNBC). TNBC shares morphological and genetic abnormalities with basal-like breast cancer (BLBC), a subgroup of breast cancer defined by gene-expression profiling. However, TNBC and BLBC tumors are heterogeneous and overlap is incomplete. Breast cancers found in BRCA1 mutation carriers are also frequently triple negative and basal like. TNBC and BLBC occur most frequently in young women, especially African Americans, and tend to exhibit aggressive, metastatic behavior. These tumors respond to conventional chemotherapy but relapse more frequently than hormone receptor-positive, luminal subtypes and have a worse prognosis. New systemic therapies are urgently needed as most patients with TNBC and/or BLBC relapse with distant metastases, and hormonal therapies and HER2-targeted agents are ineffective in this group of tumors. Poly (ADP-ribose) polymerase inhibitors, angiogenesis inhibitors, EGFR-targeted agents, and src kinase and mTOR inhibitors are among the therapeutic agents being actively investigated in clinical trials in patients with TNBC and/or BRCA1-associated tumors. Increased understanding of the genetic abnormalities involved in the pathogenesis of TNBC, BLBC and BRCA1-associated tumors is opening up new therapeutic possibilities for these hard-to-treat breast cancers.

Triple-negative breast cancer: present challenges and new perspectives

Triple-negative breast cancers (TNBC), characterized by absence of estrogen receptor (ER), progesterone receptor (PR) and lack of overexpression of human epidermal growth factor receptor 2 (HER2), are typically associated with poor prognosis, due to aggressive tumor phenotype(s), only partial response to chemotherapy and present lack of clinically established targeted therapies. Advances in the design of individualized strategies for treatment of TNBC patients require further elucidation, by combined 'omics' approaches, of the molecular mechanisms underlying TNBC phenotypic heterogeneity, and the still poorly understood association of TNBC with BRCA1 mutations. An overview is here presented on TNBC profiling in terms of expression signatures, within the functional genomic breast tumor classification, and ongoing efforts toward identification of new therapy targets and bioimaging markers. Due to the complexity of aberrant molecular patterns involved in expression, pathological progression and biological/clinical heterogeneity, the search for novel TNBC biomarkers and therapy targets requires collection of multi-dimensional data sets, use of robust multivariate data analysis techniques and development of innovative systems biology approaches.