High frequency of coexistence of columnar cell lesions, lobular neoplasia, and low grade ductal carcinoma in situ with invasive tubular carcinoma and invasive lobular carcinoma

Transcriptomic analysis of tubular carcinomas of the breast reveals similarities and differences with molecular subtype-matched ductal and lobular carcinomas

Tubular carcinoma (TC) is an uncommon special type of breast cancer characterized by an indolent clinical course. Although described as part of a spectrum of related lesions named 'low-grade breast neoplasia family' due to immunophenotypical and genetic similarities, TCs, low-grade invasive ductal carcinomas of no special type (IDC-NSTs), and classic invasive lobular carcinomas (ILCs) significantly differ in terms of histological features and clinical outcome. The aim of this study was to investigate whether pure TCs constitute an entity distinct from low-grade IDC-NSTs and from classic ILCs. To define the transcriptomic differences between TCs and IDC-NSTs and ILCs whilst minimizing the impact of histological grade and molecular subtype on their profiles, we subjected a series of grade- and molecular subtype-matched TCs and IDC-NSTs and molecular subtype-matched TCs and classic ILCs to genome-wide gene expression profiling using oligonucleotide microarrays. Unsupervised and supervised analysis revealed that TCs are similar at the transcriptomic level to grade- and molecular subtype-matched IDC-NSTs. However, subtle yet significant differences were detected and validated by quantitative reverse transcriptase-PCR, which may in part explain the reported more favourable outcome of TCs. Transcriptomic differences between TCs and molecular subtype-matched classic ILCs were more overt, predominantly due to lower expression of proliferation and cell cycle genes in TCs and down-regulation of cell adhesion/extracellular matrix-related genes in classic ILCs. Our results support the existence of a 'low-grade breast neoplasia family'; however, the transcriptomes of these lesions display small, yet important differences, which, together with their distinct biological behaviour, warrant their separation as discrete entities.

Columnar cell lesions and subsequent breast cancer risk: a nested case-control study

Introduction

Histologic and genetic evidence suggests that at least some columnar cell lesions (CCL) of the breast represent precursor lesions in the low-grade breast neoplasia pathway. However, the risk of subsequent breast cancer associated with the presence of CCL in a benign breast biopsy is poorly understood.

Methods

The authors examined the association between the presence of CCL and subsequent breast cancer risk in a nested case-control study of benign breast disease (BBD) and breast cancer within the Nurses' Health Studies (394 cases, 1,606 controls). Benign breast biopsy slides were reviewed by pathologists and CCL presence assessed. Logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) for the association between CCL and breast cancer risk.

Results

Women with CCL (140 cases, 448 controls) had an increased risk of breast cancer compared with those without CCL (OR = 1.44, 95% CI: 1.14 to 1.83), although this was attenuated and became non-significant after adjustment for the histologic category of BBD (OR = 1.20, 95% CI: 0.94 to 1.54). CCL presence was associated with the greatest risk of breast cancer for those with nonproliferative BBD (OR = 1.36, 95% CI: 0.79 to 2.37) and the lowest risk for those with atypical hyperplasia (AH) (OR = 1.10, 95% CI: 0.65 to 1.87); however, this apparent heterogeneity in risk across BBD categories was not significant (P for interaction between CCL presence and BBD category = 0.77).

Conclusions

These results provide evidence that CCL may be an important marker of breast cancer risk in women with BBD but suggest that CCL do not increase breast cancer risk independently of concurrent proliferative changes in the breast.

Early Breast Cancer Precursor Lesions: Lessons Learned from Molecular and Clinical Studies

Atypical ductal hyperplasia (ADH), flat epithelial atypia (FEA), and lobular neoplasia (LN) form a group of early precursor lesions that are part of the low-grade pathway in breast cancer development. This concept implies that the neoplastic disease process begins at a stage much earlier than in situ carcinoma. We have performed a review of the published literature for the upgrade risk to ductal carcinoma in situ or invasive carcinoma in open biopsy after a diagnosis of ADH, FEA, or LN in core needle biopsy. This has revealed the highest upgrade risk for ADH (28.2% after open biopsy), followed by LN (14.9%), and FEA (10.2%). With LN, the pleomorphic subtype is believed to confer a higher risk than classical LN. With all types of precursor lesions, careful attention must be paid to the clinicopathological correlation for the guidance of the clinical management. Follow-up biopsies are generally indicated in ADH, and if there is any radiological-pathological discrepancy, also in LN or FEA.

Low-grade ductal carcinoma in situ and invasive mammary carcinoma with columnar cell morphology arising in a complex fibroadenoma in continuity with columnar cell change and flat epithelial atypia

We describe the clinicopathologic features of a small low-grade invasive mammary carcinoma with cytomorphological columnar cell features arising in a complex fibroadenoma that in addition to sclerosing adenosis, apocrine metaplasia, and usual ductal hyperplasia also displayed columnar cell change with flat epithelial atypia and low-grade ductal carcinoma in situ merging with the invasive carcinoma. There were strong cytomorphological similarities between the invasive carcinoma and the low-grade ductal carcinoma in situ, which also showed significant overlap in the immunohistochemical findings.

Synchronous benign-appearing calcifications in patients with ductal carcinoma in situ may not be benign

BACKGROUND

The management of multiple synchronous groups of benign-appearing calcifications in patients with a diagnosis of breast cancer or a high-risk lesion requiring excision is unclear. The purpose of this study was to examine the results of biopsies of synchronous benign-appearing microcalcifications, in patients with a concurrent abnormal pathology result requiring surgery.

METHODS

A review was performed of all breast stereotactic-guided vacuum biopsies done at Elmhurst Hospital Center (Elmhurst, NY, USA) between January 2006 and February 2009. Patients with an abnormal pathology result that had further biopsies of synchronous benign or probably benign microcalcifications were included.

RESULTS

Two hundred and fifty-two patients had abnormal biopsy results. Twenty-eight patients with additional clusters of microcalcifications reported as benign or probably benign underwent 34 additional biopsies. Abnormal pathology results were found in half of these biopsies, changing the surgical plan in 14 patients. In patients with ductal carcinoma in situ (DCIS) this rate was 71%. Four patients had their diagnosis upgraded.

CONCLUSIONS

In patients with abnormal findings on stereotactic biopsy of microcalcifications, synchronous benign-appearing microcalcifications are associated with a high rate of abnormal pathology. A 'second look' at the mammogram and further biopsy of other clusters of benign-appearing microcalcifications should be considered in patients with DCIS who are planning to undergo breast-conserving treatment.

Histological types of breast cancer: how special are they?

Breast cancer is a heterogeneous disease, comprising multiple entities associated with distinctive histological and biological features, clinical presentations and behaviours and responses to therapy. Microarray-based technologies have unravelled the molecular underpinning of several characteristics of breast cancer, including metastatic propensity and histological grade, and have led to the identification of prognostic and predictive gene expression signatures. Furthermore, a molecular taxonomy of breast cancer based on transcriptomic analysis has been proposed. However, microarray studies have primarily focused on invasive ductal carcinomas of no special type. Owing to the relative rarity of special types of breast cancer, information about the biology and clinical behaviour of breast cancers conveyed by histological type has not been taken into account. Histological special types of breast cancer account for up to 25% of all invasive breast cancers. Recent studies have provided direct evidence of the existence of genotypic-phenotypic correlations. For instance, secretory carcinomas of the breast consistently harbour the t(12;15) translocation that leads to the formation of the ETV6-NTRK3 fusion gene, adenoid cystic carcinomas consistently display the t(6;9) MYB-NFIB translocation and lobular carcinomas consistently show inactivation of the CDH1 gene through multiple molecular mechanisms. Furthermore, histopathological and molecular analysis of tumours from conditional mouse models has provided direct evidence for the causative role of specific genes in the genesis of specific histological special types of breast cancer. Here we review the associations between the molecular taxonomy of breast cancer and histological special types, discuss the possible origins of the heterogeneity of breast cancer and propose an approach for the identification of novel therapeutic targets based on the study of histological special types of breast cancer.

DNA amplifications in breast cancer: genotypic-phenotypic correlations

DNA copy number changes in cancer cells, in particular, amplifications, occur frequently, have prognostic impact and are associated with subtypes of breast cancer. Some amplicons contain well-characterized oncogenes, including 11q13 (CCND1) and 17q12 (HER2). HER2 amplification and overexpression defines the HER2+ subgroup of breast cancer patients and is both a prognostic marker for poor outcome and a predictive marker for response to anti-HER2 targeted therapies. Therefore, there is considerable interest in documenting the locations of other recurring amplifications in breast cancers as they may also provide a rich source of new biomarkers and novel therapeutic targets for these subgroups. This article focuses on the genomic profiling of breast cancer, with an emphasis on the characteristics of the amplifications found in subtypes of breast cancer, including luminal (ER+)/HER2(-)), HER2+ and basal-like (ER(-)/HER2(-)), and discusses their known or potential roles in cancer biology and their clinical implications.

Breast cancer precursors revisited: molecular features and progression pathways

Increasingly more coherent data on the molecular characteristics of benign breast lesions and breast cancer precursors have led to the delineation of new multistep pathways of breast cancer progression through genotypic-phenotypic correlations. It has become apparent that oestrogen receptor (ER)-positive and -negative breast lesions are fundamentally distinct diseases. Within the ER-positive group, histological grade is strongly associated with the number and complexity of genetic abnormalities in breast cancer cells. Genomic analyses of high-grade ER-positive breast cancers have revealed that a substantial proportion of these tumours harbour the characteristic genetic aberrations found in low-grade ER-positive disease, suggesting that at least a subgroup of high-grade ER-positive breast cancers may originate from low-grade lesions. The ER-negative group is more complex and heterogeneous, comprising distinct molecular entities, including basal-like, HER2 and molecular apocrine lesions. Importantly, the type and pattern of genetic aberrations found in ER-negative cancers differ from those of ER-positive disease. Here, we review the available molecular data on breast cancer risk indicator and precursor lesions, the putative mechanisms of progression from in situ to invasive disease, and propose a revised model of breast cancer evolution based on the molecular characteristics of distinct subtypes of in situ and invasive breast cancers.

Intraductal proliferative lesions of the breast: morphology, associated risk and molecular biology

The main objectives of this review are (1) to review the histological criteria and terminology for usual ductal hyperplasia, atypical ductal hyperplasia, flat epithelial atypia and ductal carcinoma in situ; (2) to provide an overview of the risk of breast cancer associated with these various lesions; (3) to discuss established and emerging data on the molecular biology and pathogenesis of these lesions and (4) to discuss management when detected in diagnostic needle core and surgical diagnostic specimens.

Flat epithelial atypia on breast needle core biopsy: a retrospective study with clinical-pathological correlation

There are limited data to guide clinical management when flat epithelial atypia (FEA) is identified in breast needle core biopsies (NCBs). Our objectives were to determine the frequency of malignancy in subsequent breast excisions following NCB diagnosis of FEA, and to characterize the pathological and clinical features of associated tumors. Two hundred and fifty-six breast NCBs from a retrospective search (January 1999-July 2007) were blindly reviewed for FEA/other columnar cell lesions (CCLs). NCBs with co-existing carcinoma were excluded. The study included 211 NCBs: 116 (55%) with CCLs without atypia; 40 (19%) with CCLs with atypical ductal hyperplasia (ADH), 15 (7%) with FEA and 40 (19%) with FEA and ADH; 94 cases had follow-up excisions. Ductal carcinoma in situ and/or invasive carcinoma were present in: 4/26 (15%) excisions with CCLs on NCB, 11/30 (37%) with CCLs + ADH, 1/7 (14%) with FEA alone, and 9/31 (29%) with FEA + ADH. (a) FEA was more frequently seen with ADH, than without ADH in NCBs, (b) FEA and CCLs were more frequently associated with malignancy when with ADH, and (c) tumors excised following NCB diagnosis of FEA+/-ADH had favorable prognostic factors. A conservative excision is warranted following a NCB diagnosis of FEA and ADH, and may be warranted for FEA alone.

Premalignant breast neoplasia: a paradigm of interlesional and intralesional molecular heterogeneity and its biological and clinical ramifications

As is well established in invasive breast disease, it is becoming increasingly clear that molecular heterogeneity, both between and within lesions, is a prevalent, distinct phenotype of premalignant lesions of the breast. Key pathways of tumorigenesis modulate critical features of premalignant lesions such as proliferation, differentiation, stress response, and even the generation of diversity. Current studies show that evaluation of these lesions may provide clinically useful information on future tumor formation as well as biological insights into the origin and functional significance of this distinct phenotype.

Breast pathology: beyond morphology

Breast cancer is a heterogeneous disease and pathologists have evolved a system of classification that reflects this heterogeneity as well as provide prognostic and predictive information to manage patients. Professor Azzopardi's contribution to understanding and classifying breast disease is significant and reflected by the many articles in this issue. Nonetheless, there are limitations to the morphologic classification and new molecular methods promise to refine the biological understanding as well as provide better biomarkers for prognostication and targets for the development of novel therapeutics. The degree to which the new methods add value to the morphology remains to be seen, but there is hope that a symbiosis between morphology and molecular techniques will advance traditional histopathology and improve the care of patients with breast cancer.

Columnar cell lesions: a consensus study among pathology trainees

Columnar cell lesions of the breast are a spectrum of lesions in the terminal duct lobular units, which include columnar cell change, columnar cell hyperplasia, and columnar cell change or columnar cell hyperplasia with atypia. The latter was designated by the World Health Organization as flat epithelial atypia. We studied a group of pathology trainees (pathology residents and fellows) as a model for the impact of a training tutorial on the ability to distinguish various types of columnar cell lesions. Twenty-four test cases of columnar cell lesions, including 8 cases each of columnar cell change, columnar cell hyperplasia, and flat epithelial atypia, were prepared after an independent consensus on diagnosis by 2 senior pathologists with expertise in breast pathology. Fourteen pathology trainees were given a slide tutorial for the diagnostic criteria of columnar cell lesions at a multiheaded microscope. All 14 trainees entered their diagnoses of columnar cell lesions independently before and after the tutorial. The kappa values of columnar cell lesions, columnar cell hyperplasia, and flat epithelial atypia among 14 pathology trainees were 0.42, 0.25, and 0.39 before the tutorial and 0.56, 0.41, and 0.60 after the tutorial, respectively. The agreements on columnar cell lesions, columnar cell hyperplasia, and flat epithelial atypia after the tutorial were significantly better than those before the tutorial. No significant difference in agreement was observed on columnar cell change before and after the tutorial, but the kappa value improved. We conclude that appropriate tutorial training of diagnostic criteria can increase diagnostic agreement on columnar cell lesions among pathology residents, fellows, and presumably general pathologists in practice.

Columnar cell lesions of the canine mammary gland: pathological features and immunophenotypic analysis

BACKGROUND

It has been suggested that columnar cell lesions indicate an alteration of the human mammary gland involved in the development of breast cancer. They have not previously been described in canine mammary gland. The aim of this paper is describe the morphologic spectrum of columnar cell lesions in canine mammary gland specimens and their association with other breast lesions.

METHODS

A total of 126 lesions were subjected to a comprehensive morphological review based upon the human breast classification system for columnar cell lesions. The presence of preinvasive (epithelial hyperplasia and in situ carcinoma) and invasive lesions was determined and immunophenotypic analysis (estrogen receptor (ER), progesterone receptor (PgR), high molecular weight cytokeratin (34betaE-12), E-cadherin, Ki-67, HER-2 and P53) was perfomed.

RESULTS

Columnar cell lesions were identified in 67 (53.1%) of the 126 canine mammary glands with intraepithelial alterations. They were observed in the terminal duct lobular units and characterized at dilated acini may be lined by several layers of columnar epithelial cells with elongated nuclei. Of the columnar cell lesions identified, 41 (61.2%) were without and 26 (38.8%) with atypia. Association with ductal hyperplasia was observed in 45/67 (67.1%). Sixty (89.5%) of the columnar cell lesions coexisted with neoplastic lesions (20 in situ carcinomas, 19 invasive carcinomas and 21 benign tumors). The columnar cells were ER, PgR and E-cadherin positive but negative for cytokeratin 34betaE-12, HER-2 and P53. The proliferation rate as measured by Ki-67 appeared higher in the lesions analyzed than in normal TDLUs.

CONCLUSIONS

Columnar cell lesions in canine mammary gland are pathologically and immunophenotypically similar to those in human breast. This may suggest that dogs are a suitable model for the comparative study of noninvasive breast lesions.

The molecular underpinning of lobular histological growth pattern: a genome-wide transcriptomic analysis of invasive lobular carcinomas and grade- and molecular subtype-matched invasive ductal carcinomas of no special type

Invasive lobular carcinoma (ILC) is the most frequent special type of breast cancer. The majority of these tumours are of low histological grade, express hormone receptors, and lack HER2 expression. The pleomorphic variant of ILCs (PLCs) is characterized by atypical cells with pleomorphic nuclei and is reported to have an aggressive clinical behaviour. Expression profiling studies have demonstrated that classic ILCs preferentially display a luminal phenotype, whereas PLCs may be of luminal, HER2 or molecular apocrine subtypes. The aims of this study were two-fold: to determine the transcriptomic characteristics of lobular carcinomas and to define the genome-wide transcriptomic differences between classic ILCs and PLCs. To define the transcriptomic characteristics of ILCs, minimizing the impact of histological grade and molecular subtype on the analysis, we subjected a series of grade- and molecular subtype-matched ILCs and invasive ductal carcinomas (IDCs) to genome-wide gene expression profiling using oligonucleotide microarrays. Hierarchical clustering analysis demonstrated that ILCs formed a separate cluster and a supervised analysis revealed that 5.8% of the transcriptionally regulated genes were significantly differentially expressed in ILCs compared to grade- and molecular subtype-matched IDCs. ILCs displayed down-regulation of E-cadherin and of genes related to actin cytoskeleton remodelling, protein ubiquitin, DNA repair, cell adhesion, TGF-beta signalling; and up-regulation of transcription factors/immediate early genes, lipid/prostaglandin biosynthesis genes, and cell migration-associated genes. Supervised analysis of classic ILCs and PLCs demonstrated that less than 0.1% of genes were significantly differentially expressed between these tumour subtypes. Our results demonstrate that ILCs differ from grade- and molecular subtype-matched IDCs in the expression of genes related to cell adhesion, cell-to-cell signalling, and actin cytoskeleton signalling. However, classic ILCs and PLCs are remarkably similar at the molecular level and should be considered as part of a spectrum of lesions.

Histological and molecular types of breast cancer: is there a unifying taxonomy?

Breast cancer is a complex and heterogeneous disease, comprising multiple tumor entities associated with distinctive histological patterns and different biological features and clinical behaviors. Microarray-based high-throughput technologies have been employed to unravel the molecular characteristics of breast cancer, including its proclivity to disseminate to distant sites, and the molecular basis for histological grade. In addition, a breast cancer molecular taxonomy based solely on transcriptomic analysis has been proposed. Most microarray studies have focused on invasive ductal carcinomas of no special type, neglecting the important information about the biology and clinical behavior of breast cancers conveyed by histological type. Histological special types of breast cancer account for up to 25% of all invasive breast cancers. The histopathological characteristics of these cancers might be driven by specific genetic alterations, providing direct evidence for genotypic-phenotypic correlations between morphological patterns and molecular changes in breast cancer. We review the historical aspects of breast cancer taxonomy, discuss the possible origins of the diversity of breast cancer and propose an approach for the identification of novel therapeutic targets on the basis of histological special types of breast cancer.

Rates of atypical ductal hyperplasia have declined with less use of postmenopausal hormone treatment: findings from the Breast Cancer Surveillance Consortium

AIM

To examine risk factors and rates of atypical ductal hyperplasia (ADH) with and without associated breast cancer over time and tumor characteristics of breast cancer with and without associated ADH in women previously screened with mammography.

METHODS

Data on screening mammograms done between 1996 and 2005 were collected from mammography registries that participate in the Breast Cancer Surveillance Consortium. Associations between age, family history of breast cancer, postmenopausal hormone treatment (HT), and final pathology result (ADH or cancer with or without ADH in the same breast) were examined. Rates of different outcomes were calculated per exam year. Tumor characteristics of cancers with and without associated ADH were compared.

RESULTS

A total of 2,453,483 screening mammograms were associated with 1,064 biopsies with ADH, 833 breast cancers with ADH, and 8,161 cancers with no ADH. Postmenopausal HT use decreased significantly from 35% to 11% during the study period. Rates of ADH decreased from a peak of 5.5/10,000 mammograms in 1999 to 2.4/10,000 in 2005. Rates of cancer with ADH decreased from a peak of 4.3/10,000 mammograms in 2003 to 3.3/10,000 in 2005. ADH and breast cancer were significantly associated with use of postmenopausal HT. Cancer associated with ADH was of lower grade and stage and more estrogen receptor positive than cancer with no ADH.

SUMMARY

Postmenopausal HT is associated with an increased risk of ADH with or without cancer. Rates of ADH have decreased over the past decade, which may be partially explained by the significant reduction in use of postmenopausal HT.

[Pathological aspects of in situ carcinoma/intraepithelial neoplasia of the breast]

Dramatic development has happened in the field of classical and molecular breast pathology in the last three decades. Introduction of systematic screening programs advanced our knowledge in the field of classical surgical pathology, while molecular technical revolution resulted in dramatic improvement of our understanding of molecular pathology of breast tumors and precancerous lesions. This continuous increase of our knowledge results in the change of our concepts, classifications and approach. In this review, I would like to share the new and recently adapted views regarding intraepithelial neoplastic lesions of the breast.

Clonal relationship between closely approximated low-grade ductal and lobular lesions in the breast: a molecular study of 10 cases

The relationship between ductal and lobular breast carcinoma is highlighted in cases in which these morphologically divergent carcinomas coexist in proximity within a single patient. We hypothesized that such cases may result from the proliferation of a precursor lesion into a tumor containing areas of divergent morphologic features. In this study, we analyzed loss of heterozygosity (LOH) in 10 cases of coexistent ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), and invasive carcinoma. DNA from the separate components of each lesion was subjected to LOH analysis using 13 markers on 7 chromosomes. In 7 cases, the DCIS and LCIS shared loss of a common allele, suggesting a clonal relationship. The invasive component shared loss of the same allele in 5 tumors. This finding indicates that coexistent lobular and ductal carcinomas exhibit shared genetic abnormalities, contradicting the conventional concept that these lesions represent separate, exclusive pathways of breast neoplasia. Instead, these traditionally segregated classes of breast cancer may, in fact, share common precursor lesions.

Invasive tubular carcinoma of the breast frequently is clonally related to flat epithelial atypia and low-grade ductal carcinoma in situ

Low-grade precursor lesions, such flat epithelial atypia (FEA), low-grade ductal carcinoma in situ (lg-DCIS), and lobular neoplasia (LN) often coexist with invasive tubular carcinomas (TCs) of the breast. To evaluate a possible clonal relationship, we have examined a series of 27 TC and the surrounding putative precursor lesions using loss of heterozygosity analysis and mitochondrial DNA sequencing. In these lesions (22 FEA, 10 lg-DCIS, 3 LN), loss of heterozygosity was most frequently observed on the long arm of chromosome 16 as well as at chromosome 8p21, 3p14, 1p36 and 11q14 with a high degree of homology of allelic losses between FEA, lg-DCIS and tubular carcinomas. In the adjacent invasive tubular carcinomas, mitochondrial DNA sequencing revealed identical mutation patterns in 50% of the lg-DCIS and in 12 of 21 (57%) informative cases of FEA. No direct association was seen between TC and LN or columnar cell lesions without nuclear atypia. Our data indicate, that in the majority of cases lg-DCIS and FEA are directly related to tubular breast cancer with a possible precursor role.

[Atypical ductal and lobular hyperplasia of the breast]

Atypical hyperplasia represents 4% of all benign breast diseases. There are two different types: atypical ductal hyperplasia and atypical lobular hyperplasia. Aside columnar cell lesion. They represent an early stage of some forms of low grade carcinoma in situ and invasive carcinomas. Atypical hyperplasia is a benign lesion with intermediate carcinologic risk and the existence of a concomitant aggressive lesion should be suspected. When atypical lesion is found on a biopsy specimen, surgical excision is recommended especially in case of atypical ductal hyperplasia. A regular supervision is recommended.

Genetic characterization of breast cancer and implications for clinical management

Breast cancer is a genetic disease caused by the accumulation of mutations in neoplastic cells. In the last few years, high-throughput microarray-based molecular analysis has provided increasingly more coherent information about the genetic aberrations in breast cancer. New biomarkers and molecular techniques are slowly becoming part of the diagnostic and prognostic armamentarium available for pathologists and oncologists to tailor the therapy for breast cancer patients. In this review, we will focus on the contribution of breast cancer somatic genetics to our understanding of breast cancer biology and its impact on breast cancer patient management.

Flat epithelial atypia on core needle biopsy: which is the right management?

The clinical significance and management (surgical excision vs. follow-up) of the patients with the diagnosis of flat epithelial atypia (FEA) on core needle biopsy (CNB) are actually under discussion. Using standardized criteria and precise terminology, we analyzed retrospectively our CNB diagnosis of FEA, dividing patients with pure FEA as the most advanced pathologic lesion from patients with FEA associated to atypical ductal hyperplasia (FEA+ADH). Both the categories were correlated with radiologic data and findings on subsequent surgery. We evaluated 875 core needle biopsies (11-gauge stereotactic vacuum-assisted procedure), performed over a 5-year period. A CNB diagnosis of pure FEA was made in 33/875 (3.7%) cases; in other 11 (1.2%) cases we observed the coexistence of FEA and ADH. Subsequent surgical excisions were available in 20/33 pure FEA and in 10/11 FEA+ADH: of the 20 patients with pure FEA on CNB, none had either ductal carcinoma in situ or invasive carcinoma in their excisional biopsy, whereas 3/10 (30%) FEA+ADH on CNB showed, at subsequent surgery, more advanced lesions (2 ductal carcinoma in situ, 1 invasive carcinoma). Our results suggest that patients with an 11-gauge vacuum-assisted CNB diagnosis of pure FEA (especially if related to a small radiologic target, completely or almost completely removed by the needle biopsy procedure) could be spared surgical excision and managed with close radiologic follow-up.

The expression of ERalpha, ERbeta and PR in lobular carcinoma in situ of the breast determined using laser microdissection and real-time PCR

AIMS

To determine the status of oestrogen receptor (ER) subtypes (ERalpha and ERbeta) in lobular carcinoma in situ (LCIS) of the breast.

METHODS AND RESULTS

Forty-seven cases of LCIS and six cases with normal breast lobules were subjected to immunohistochemistry and evaluated for ERalpha, ERbeta and progesterone receptor (PR) expression. mRNA for ERalpha, ERbeta1 and ERbeta2 were quantified in LCIS and normal lobules using laser microdissection coupled with real-time polymerase chain reaction. LCIS showed a higher level of steroid receptor protein expression than normal lobules. There was no difference in ERbeta1 gene or ERbeta protein expression between normal lobules, pure LCIS, or LCIS associated with invasive breast cancer. No significant difference in expression of either ERalpha or ERbeta was found between pure LCIS and LCIS associated with invasive cancer. However, PR was significantly lower in those cases of LCIS with associated invasive than in those without synchronous invasive disease.

CONCLUSIONS

Increased expression of steroid receptors in LCIS suggests their possible role in the biology of LCIS and, for PR, could influence the predisposition of women diagnosed with LCIS to develop invasive breast carcinoma.

Lobular Carcinoma in Situ, Classical Type and Unusual Variants

The morphologic spectrum of lobular carcinoma in situ (LCIS) includes the classical type and unusual variants recently described. In this article we review the morphology of LCIS and highlight ways to distinguish it from its morphologic mimickers.

Clinicopathologic implications of "flat epithelial atypia" in core needle biopsy specimens of the breast

Flat epithelial atypia (FEA) is an emerging entity of uncertain clinical significance, and outcome data are sparse. The aim of this study was to evaluate the clinicopathologic significance of this entity for proper management. All core needle biopsy (CNB) specimens diagnosed as atypical ductal hyperplasia (ADH) from January 2006 to April 2008 were retrieved. H&E-stained slides of 5 levels on each case were reviewed. The differences in upstaging in subsequent excisions in the FEA and ADH group (31/189 [16.4%]) vs the pure FEA group (5/35 [14%]) and pure FEA (5/35 [14%]) vs pure ADH (5/45 [11%]) were not statistically significant. We observed that FEA evolved into ADH at the same site at an average of 3 to 4 levels. Our study concludes that there is an association of FEA with ADH on multiple levels of CNB specimens, and follow-up surgical excision findings for FEA are clinically significant.

Columnar cell lesions associated with breast calcifications on vacuum-assisted core biopsies: clinical, radiographic, and histological correlations

Columnar cell lesions of the breast are increasingly recognized at mammography for their tendency to calcify. We studied 392 vacuum-assisted core biopsies performed solely for calcifications to evaluate the frequency of columnar cell lesions, their relationship with radiological risk, appearance of calcifications, and clinical data. Management and follow-up of columnar cell lesions without and with atypia (flat epithelial atypia) was analyzed. Cases with architectural atypia (cribriform spaces and/or micropapillae) were excluded from flat epithelial atypia. Calcifications were within the lumen of acini affected by columnar cell lesions in 137 out of 156 biopsies diagnosed with some columnar cell lesions. These represented 37% of vacuum-assisted core biopsies and 62% of low radiological risk (BI-RADS3) calcifications. High-risk (BI-RADS5) calcifications were never associated with columnar cell lesions. Age and menopausal status were comparable in columnar and in not-columnar cell lesions. Atypia was associated with long-term hormone replacement therapy in both lesions. Surgical biopsy was recommended for all cases with atypia. Flat epithelial atypia, as the only histological findings on vacuum-assisted core biopsies, was never associated with malignancy at surgery. In conclusion, we suggest that surgical excision is not mandatory when flat epithelial atypia is found as the most advanced lesion on vacuum-assisted core biopsy performed for low radiological risk calcifications, and that women should be advised of the possible hormone dependency of this entity.

Flat Ductal Intraepithelial Neoplasia of the Breast: A Review of Diagnostic Criteria, Differential Diagnoses, Molecular-Genetic Findings, and Clinical Relevance—It Is Time to Appreciate the Azzopardi Concept!

Context.—More than 25 years ago, John G. Azzopardi described a distinctive intraepithelial neoplastic breast lesion, which he designated “clinging carcinoma in situ”; he considered it as another variant of ductal carcinoma in situ, an early lesion that can easily be missed because the changes are mainly cytologic rather than architectural. The lesion remained widely unrecognized and/or ignored until recent years when its neoplastic nature was confirmed at the molecular-genetic level.

Objective.—To deal with historical aspects of the evolving concept of “clinging” and to focus on several important issues such as characteristic morphologic features with particular attention to the diagnostic criteria and differential diagnoses, recent molecular-genetic findings, appropriate terminology and classification, as well as the significance of this type of lesion for both surgical pathologists and clinicians.

Data Sources.—A thorough search of the literature was performed and publications using a variety of designations including “clinging carcinoma in situ,” “flat epithelial atypia,” “ductal intraepithelial neoplasia-flat type,” “atypical cystic lobules,” “columnar cell change with atypia,” “columnar cell hyperplasia with or without atypia,” “columnar alteration with prominent apical snouts and secretion,” and so forth were reviewed.

Conclusions.—This distinctive lesion represents one of the earliest morphologically recognizable neoplastic alterations of the breast that is commonly associated with mammographically suspicious microcalcifications. It is characterized by mildly to severely atypical cells simply replacing the single layer of native epithelial cells in a flat fashion without appreciable proliferation; tufting, intraluminal bridging, micropapillary structures, and so forth are typically absent or very focal and minimal, if present at all. Based on the degree of cytologic atypia, low- and high-grade flat ductal intraepithelial neoplasia need to be separated. Although additional studies are needed to better understand the clinical significance of flat ductal intraepithelial neoplasia, several lines of evidence strongly support the concept of clinging. Indeed, as pointed out by Azzopardi, surgical pathologists need to pay more attention to the cytologic alterations of the breast lesions by analyzing the involved cell populations using high-power magnification.

Flat Epithelial Atypia of the Breast

Lesions of the breast characterized by enlarged terminal duct lobular units lined by columnar epithelial cells are being encountered increasingly in breast biopsy specimens. Some of these lesions feature cuboidal to columnar epithelial cells in which the lining cells exhibit cytologic atypia. The role of these lesions (recently designated "flat epithelial atypia" [FEA]) in breast tumor progression is still emerging. FEA commonly coexists with well-developed examples of atypical ductal hyperplasia, low-grade ductal carcinoma in situ, lobular neoplasia, and tubular carcinoma. These findings and those of recent genetic studies suggest that FEA is a neoplastic lesion that may represent a precursor to or the earliest morphologic manifestation of ductal carcinoma in situ. Additional studies are needed to better understand the biologic nature and clinical significance of these lesions.

Loss of 16q in high grade breast cancer is associated with estrogen receptor status: Evidence for progression in tumors with a luminal phenotype?

Loss of the long arm of chromosome 16 (16q) is observed in the vast majority of low grade/grade I (GI) invasive ductal carcinomas of no special type (IDC-NSTs), whereas this event is uncommonly seen in high grade/grade III (GIII) IDC-NSTs. Together with data on the pathology and genetics of breast cancer recurrences, this has led to the proposal that GI and GIII breast cancers evolve through distinct genetic pathways and that progression from GI to GIII is an unlikely biological phenomenon. We compared the genomic profiles of GIII-IDC-NSTs with 16q whole arm loss (16qWL) according to estrogen receptor (ER) status. 16qWL was found in 36.5% of cases and was significantly associated with ER expression and luminal phenotype. ER+ GIII-IDC-NSTs with 16qWL displayed significantly higher levels of genomic instability than ER+ IDC-NSTs without 16qWL. Furthermore, ER+ and ER- IDC-NSTs stratified according to the presence of 16qWL harbored distinct patterns of genetic aberrations. Interestingly, ER+/16qWL tumors displayed genetic features usually found in tumors with homologous DNA repair defects and significantly more frequently harbored heterozygous loss of BRCA2 than the remaining ER+ cancers. Our results demonstrate that approximately one third of GIII tumors harbor 16qWL, confirming that progression from low to high grade breast cancer is not found in the majority of breast cancers. 16qWL was significantly more prevalent in ER+/luminal GIII-IDC-NSTs. Given that GI breast cancers harbor a luminal phenotype, our results suggest that if progression from GI to GIII breast cancer does happen, it may preferentially occur in breast cancers of luminal phenotype.

Columnar cell lesions of the breast: an update and significance on core biopsy

Columnar cell lesions of the breast refer to the morphological spectrum of alterations of the epithelial lining of variably dilated acini of the terminal duct lobular unit (TDLU), often related to secretions and calcifications. After decades of varied terminologies, the term of 'flat epithelial atypia' by the World Health Organization (WHO) consensus group encompasses the part of the spectrum where columnar cell change or columnar cell hyperplasia acquires low grade cytological atypia, merging with atypical ductal hyperplasia and low grade ductal carcinoma in situ. Its association with low grade invasive carcinoma and lobular neoplasia, whether by proximity to these lesions, or by similar molecular expressions, has prompted greater scrutiny into its clinical significance. Although recent literature attempts to refine the term 'flat epithelial atypia', the applicability of its morphological criteria in routine diagnostic practice remains to be seen, and interobserver variability is highly possible. This poses even greater challenges especially in limited samples of breast tissue, such as in core biopsies, for pre-operative decision-making. The purpose of this review is to elucidate evolving clinical and diagnostically relevant principles that surround and influence the significance of this still controversial entity, especially when discovered on core biopsy in the initial phase of breast diagnosis and management.