The Spectrum of Morphomolecular Abnormalities of the E-Cadherin/Catenin Complex in Pleomorphic Lobular Carcinoma of the Breast

Upgrade Rates of Variant Lobular Carcinoma In Situ Compared to Classic Lobular Carcinoma In Situ Diagnosed in Core Needle Biopsies: A 10-Year Single Institution Retrospective Study

The primary aim of this study was to determine the upgrade rates of variant lobular carcinoma in situ (V-LCIS, ie, combined florid [F-LCIS] and pleomorphic [P-LCIS]) compared with classic LCIS (C-LCIS) when diagnosed on core needle biopsy (CNB). The secondary goal was to determine the rate of progression/development of invasive carcinoma on long-term follow-up after primary excision. After institutional review board approval, our institutional pathology database was searched for patients with "pure" LCIS diagnosed on CNB who underwent subsequent excision. Radiologic findings were reviewed, radiologic-pathologic (rad-path) correlation was performed, and follow-up patient outcome data were obtained. One hundred twenty cases of LCIS were identified on CNB (C-LCIS = 97, F-LCIS = 18, and P-LCIS = 5). Overall upgrade rates after excision for C-LCIS, F-LCIS, and P-LCIS were 14% (14/97), 44% (8/18), and 40% (2/5), respectively. Of the total cases, 79 (66%) were deemed rad-path concordant. Of these, the upgrade rate after excision for C-LCIS, F-LCIS, and P-LCIS was 7.5% (5 of 66), 40% (4 of 10), and 0% (0 of 3), respectively. The overall upgrade rate for V-LCIS was higher than for C-LCIS (P = .004), even for the cases deemed rad-path concordant (P value: .036). Most upgraded cases (23 of 24) showed pT1a disease or lower. With an average follow-up of 83 months, invasive carcinoma in the ipsilateral breast was identified in 8/120 (7%) cases. Six patients had died: 2 of (contralateral) breast cancer and 4 of other causes. Because of a high upgrade rate, V-LCIS diagnosed on CNB should always be excised. The upgrade rate for C-LCIS (even when rad-path concordant) is higher than reported in many other studies. Rad-path concordance read, surgical consultation, and individualized decision making are recommended for C-LCIS cases. The risk of developing invasive carcinoma after LCIS diagnosis is small (7% with ∼7-year follow-up), but active surveillance is required to diagnose early-stage disease.

Establishment and characterisation of cell lines and xenograft mouse models of canine systemic histiocytosis and disseminated histiocytic sarcoma

Canine histiocytic proliferative disorders include reactive diseases (histiocytosis) and neoplastic diseases (histiocytic sarcoma [HS]), however discrimination is challenging due to their overlapping pathological features. In the present study, novel cell lines and xenograft mouse models of systemic histiocytosis (SyH) and disseminated HS were established, and examined together with cell lines previously established from localized HS and Langerhans cell histiocytosis (LCH). The chromosomal numbers of the SyH and HS cell lines were abnormal, and their population doubling time and morphological features were comparable. Immunophenotypically, SyH and HS cells were CD204+/E-cadherin+ in vitro and in vivo, like their original tissues. Western blot analysis for E-cadherin revealed an immunopositive band of full-length E-cadherin (120 kDa) in cultured cells of localized HS and LCH but not in disseminated HS and SyH; expression level was weaker in localized HS than in LCH. An immunopositive band of fragmented E-cadherin (45 kDa) was detected in cell lines of disseminated HS and SyH. These results suggest that cultured SyH cells have features that are similar to disseminated HS, including chromosomal aberration, high proliferation activity, weak cell adhesion, and expression of fragmented E-cadherin. Fragmentation of the E-cadherin cell adhesion molecule may be associated with the loss of cell adhesion and increased abilities of invasion and migration of neoplastic cells. The established cell lines and xenograft mouse models will aid in understanding the pathogenesis and developing novel treatments of canine histiocytic proliferative disorders.

BCL3 expression is strongly associated with the occurrence of breast cancer relapse under tamoxifen treatment in a retrospective cohort study

Patients with estrogen receptor positive breast cancer are usually receiving an anti-estrogen therapy by either aromatase inhibitors or selective estrogen receptor mediators such as tamoxifen. Nevertheless, acquired resistance to tamoxifen under treatment frequently hampers therapy. One proposed explanation for this phenomenon is the interaction of the tumor cells with cells of the tumor microenvironment via the Insulin-like growth factor RNA binding protein 5/B-cell lymphoma 3 (IGFBP5/BCL3) axis. Here we investigated whether a high expression of BCL3 either cytoplasmic or nuclear is associated with the occurrence of a relapse under anti-estrogen therapy in patients. Formaldehyde-fixed, paraffin-embedded samples of 180 breast cancer patients were analyzed for BCL3 expression by immunohistochemistry. An immunoreactive score (IRS) was calculated from staining intensity in cytoplasm and nucleus as well as the percentage of positive tumor cells. These scores were correlated with clinico-pathological parameters using cross-tabulation analysis and patients’ relapse free and overall survival by Kaplan–Meier analysis and Cox regression. A tamoxifen-adapted MCF-7 derived cell line was investigated for BCL3 localization by immunofluorescence. The cytosolic BCL3-IRS significantly correlated with the proliferation marker Ki-67, and with the occurrence of a relapse under tamoxifen treatment. Nuclear score correlated only with tamoxifen-relapse. In survival analysis, both scores were highly significant prognostic factors for relapse free, but not for overall survival. This was especially obvious for estrogen receptor positive and HER2/NEU negative cases as well as lobular breast cancer. Tamoxifen-treated, but not aromatase-treated patients had a poor survival when BCL3 scores were high. A tamoxifen adapted cell line exhibited a reduced expression and mainly nuclear localization of BCL3, compared to the parental estrogen receptor positive cell-line MCF-7. Altogether, these data strongly support a function of BCL3 in tamoxifen resistance and its potential use as a predictive biomarker for tamoxifen resistance.

Morphologic subtypes of lobular carcinoma in situ diagnosed on core needle biopsy: clinicopathologic features and findings at follow-up excision

Lobular carcinoma in situ (LCIS) is currently classified as classic (CLCIS), florid (FLCIS), and pleomorphic (PLCIS). Given the rarity of FLCIS and PLCIS, information on their clinico-pathologic features and biologic potential remains limited. We evaluated the upgrade rates at excision of FLCIS and PLCIS diagnosed on inhouse core needle biopsy (CNB) and their clinical presentation and follow-up. Over a period of 11 and a half years, there were a total of 36 inhouse CNBs with pure PLCIS (n = 8), FLCIS (n = 24), or LCIS with pleomorphic features (LCIS-PF) (n = 4). The upgrade rates to invasive carcinoma or ductal carcinoma in situ (DCIS) were 25% for PLCIS (2/8), 17% for FLCIS (4/24), and 0% for LCIS-PF (0/4). The overall upgrade rate of PLCIS and FLCIS combined was 19% (6/32). All but one case (not upgraded at excision) were radiologic-pathologic concordant. Apocrine features, previously reported only in PLCIS, were also noted in FLCIS. HER2 overexpression was seen in 13% of cases. This study highlights the more aggressive biologic features of PLCIS and FLCIS compared to CLCIS and supports surgical management for these lesions.

Invasive Lobular Breast Cancer as a Distinct Disease: Implications for Therapeutic Strategy

Invasive lobular carcinoma comprises 10-15% of all breast cancers and is increasingly recognised as a distinct and understudied disease compared with the predominant histological subtype, invasive ductal carcinoma. Hallmarks of invasive lobular carcinoma include E-cadherin loss, leading to discohesive morphology with cells proliferating in single-file strands and oestrogen receptor positivity, with favourable response to endocrine therapy. This review summarises the distinct histological and molecular features of invasive lobular carcinoma with focus on diagnostic challenges and the impact on surgical management and medical therapy. Emphasis is placed on recent advances in our understanding of the unique molecular biology of lobular breast cancer and how this is optimising our therapy approach in the clinic.

Immunohistochemistry for diagnosis and prognosis of breast cancer: a review

Breast cancer is the most prevalent malignant tumor and main oncologic cause of mortality in women. Although most diagnosis of breast pathology is accomplished using hematoxylin and eosin stained sections, some cases require immunohistochemistry for proper evaluation. We investigated the latter cases including distinctions between ductal and lobular carcinoma, in situ and invasive carcinoma, typical ductal hyperplasia and atypical ductal hyperplasia/ductal carcinoma in situ, papillary and spindle cell lesion assessment, metastasis evaluation, and assessment of prognostic and therapy markers. E-cadherin is used to differentiate ductal and lobular carcinoma; 34βE12, CK8, p120 catenin and β-catenin also produce consistent results. Myoepithelial cell (MEC) stains are used to evaluate in situ and invasive carcinoma; calponin, smooth muscle myosin heavy chain and p63 are sensitive/specific markers. 34βE12 and CK5/6 are positive in ductal hyperplasia, which enables its differentiation from atypical ductal hyperplasia and ductal carcinoma in situ. CK 5/6, ER and MEC markers are consistent options for evaluating papillary lesions. Spindle cell lesions can be assessed using β-catenin, SMA, CD34, p63, CKs and hormone receptors. It is important to differentiate primary carcinomas from metastases; the most commonly used markers to identify breast origin include mammaglobin, GCDFP-15, GATA3 and ER, although none of these is completely sensitive or specific. Immunohistochemistry can be used to evaluate central prognostic and predictive factors including molecular subtypes, HER2, hormone receptors, proliferation markers (Ki-67) and lymph-vascular invasion markers including ERG, CD31, CD34, factor VIII and podoplanin. Owing to the complexity of mammary lesions, diagnosis also depends on each particular situation, evaluation of cytological characteristics revealed by immunochemistry and correlation with histological findings.

Core Needle Biopsy of the Breast: An Evaluation of Contemporary Data

Benign and atypical lesions associated with breast cancer risk are often encountered in core needle biopsies (CNBs) of the breast. For these lesions, the rate of "upgrade" to carcinoma in excision specimens varies widely in the literature. Many CNB studies are limited by a lack of radiological-pathological correlation, consistent criteria for excision, and clinical follow-up for patients who forego excision. This article highlights contemporary diagnostic criteria and outcome data that would support an evidence-based approach to the management of these nonmalignant lesions of the breast diagnosed on CNB.

Lobular Carcinoma In Situ

Lobular carcinoma in situ (LCIS) is a risk factor and a nonobligate precursor of breast carcinoma. The relative risk of invasive carcinoma after classic LCIS diagnosis is approximately 9 to 10 times that of the general population. Classic LCIS diagnosed on core biopsy with concordant imaging and pathologic findings does not mandate surgical excision, and margin status is not reported. The identification of variant LCIS in a needle core biopsy specimen mandates surgical excision, regardless of radiologic-pathologic concordance. The presence of variant LCIS close to the surgical margin of a resection specimen is reported, and reexcision should be considered.

Core Breast Biopsies Showing Lobular Carcinoma In Situ Should Be Excised and Surveillance Is Reasonable for Atypical Lobular Hyperplasia

OBJECTIVE

The purpose of this article is to determine the upgrade rate to ductal carcinoma in situ (DCIS) or invasive carcinoma at excision at the same site after percutaneous breast biopsy findings of atypical lobular hyperplasia (ALH) or lobular carcinoma in situ (LCIS) using current imaging and strict pathologic criteria.

MATERIALS AND METHODS

From January 2006 through September 2013, 32,960 breast core biopsies were performed; 1084 (3.3%) core biopsies found ALH or classic LCIS. For 447 lesions in 433 women, this was the only high-risk lesion at that site, with no ipsilateral malignancy, and results of excision were available.

RESULTS

Among the 447 lesions, 22 (4.9%) were malignant at excision, including 10 invasive carcinomas (two grade 2 and eight grade 1; all node negative) and 12 DCIS. The upgrade rate of LCIS was 9.3% (10/108; 95% CI, 5.1-16.2%) and that of ALH was 3.5% (12/339; 95% CI, 2.0-6.1%; p = 0.02). After excluding five cases with radiologic-pathologic discordance and reclassifying one core from ALH to LCIS at review, the upgrade rate for LCIS remained higher (8.4%; 9/107; 95% CI, 4.5-15.2%) than that for ALH (2.4%; 8/335; 95% CI, 1.2-4.6%; p = 0.01).

CONCLUSION

Excision is recommended for LCIS on core biopsy because of its 8.4-9.3% upgrade rate. Excluding discordant cases, patients with other high-risk lesions or concurrent malignancy, the risk of upgrade of ALH was 2.4%. Surveillance at 6, 12, and 24 months can be performed in lieu of excision because a short delay in diagnosis of the few malignancies is not expected to cause harm.

Invasive Pleomorphic Lobular Carcinoma of the Breast: Pathologic, Clinical, and Therapeutic Considerations

Pleomorphic lobular carcinoma is an uncommon form of breast cancer and a subtype of invasive lobular carcinoma. It has unique histopathologic features that translate to a more aggressive phenotype with an associated poor prognosis. Unlike classical invasive lobular carcinoma, it can lose estrogen and progesterone receptor expression and demonstrate HER-2/neu amplification. It remains to be determined, however, whether the pleomorphic histology independently predicts a worse outcome or whether other known associated negative prognostic factors such as larger tumor size, increased metastatic disease, and associated worse molecular subtypes commonly present in pleomorphic carcinoma account for the poor prognosis. Here we present an updated review of the unique pathologic and clinical features of pleomorphic lobular carcinoma needed to guide management for women with this subtype of cancer.

Application of immunohistochemistry in breast pathology: a review and update

CONTEXT

Immunohistochemistry is a valuable tool in routine breast pathology, used for both diagnostic and prognostic parameters. The diagnostic immunomarkers are the scope of this review. Most breast lesions can be diagnosed on routine hematoxylin-eosin sections; however, in several scenarios, such as morphologically equivocal cases or metastatic tumors of unknown primary, the appropriate application of immunohistochemistry adds true value in reaching an accurate diagnosis.

OBJECTIVE

To evaluate the diagnostic utility of the most commonly studied immunomarkers in the field of breast pathology by review of the literature, using the database of indexed articles in PubMed (US National Library of Medicine, Bethesda, Maryland) from 1976 to 2013.

DATA SOURCES

Literature review, and author's research data and personal practice experience.

CONCLUSIONS

The appropriate use of immunohistochemistry by applying a panel of immunomarkers and using a standardized technical and interpretational method will complement the morphologic assessment and aid in the accurate classification of difficult breast lesions and the identification of metastasis from a breast primary.

When is excision necessary for atypical lobular hyperplasia and lobular carcinoma in situ?

SUMMARY This management perspective briefly covers the histology and molecular features of lobular in situ neoplasia and provides an in-depth discussion of the need for surgical excision if lobular in situ neoplasia is diagnosed on core-needle biopsy. The management of lobular in situ neoplasia found on core-needle biopsy has been an area of recent study with varying results. Emerging data suggest that low-risk patients with a limited extent of isolated classic lobular in situ neoplasia found on core-needle biopsy may not require subsequent surgical excision. However, high-risk patients, those with extensive lobular in situ neoplasia, or other high-risk lesions noted on core-needle biopsy likely benefit from surgical excision. Most authors recommend surgical excision when pleomorphic lobular carcinoma in situ is found on core-needle biopsy due to its higher association with invasive carcinoma. However, the natural history of this more recently described variant of lobular carcinoma in situ is not fully defined, and the clinical management of pleomorphic lobular carcinoma in situ on excisional biopsy is yet to be determined.

Invasive lobular carcinoma of the breast: patient response to systemic endocrine therapy and hormone response in model systems

Invasive lobular carcinoma of the breast (ILC) represents 10-15% of all newly diagnosed breast cancers, affecting ∼30,000 women annually in the United States. However, ILC is critically understudied as a breast cancer subtype. Though the vast majority of ILC are estrogen receptor-positive and present with overall favorable biomarkers, ILC patients do not benefit from improved outcomes versus other breast cancer patients. Patient outcomes, in particular in response to endocrine therapies, are not well understood in ILC, due in large part to the lack of prospective identification in large clinical trials. Further, there is a lack of laboratory models to study cell signaling, hormone response, and endocrine resistance in ILC. In this review, we provide an overview of clinicopathological features of ILC tumors, discuss issues with clinical management, and highlight the disconnect between ILC biomarkers and patient outcomes. We review currently available data on ILC patient outcomes, with a focus on response to endocrine therapy. Additionally, we describe currently available laboratory models for understanding hormone response in ILC cells, and review current data on these model systems. The promise for new insight into ILC, based on extensive representation of the disease in recent large scale genomic studies, is also discussed. Increasing understanding of endocrine response in ILC represents a critical area for future research to improve patient outcomes for this understudied breast cancer subtype.

Immunohistochemistry applied to the differential diagnosis between ductal and lobular carcinoma of the breast

The distinction between classic lobular and ductal carcinoma, both in situ and invasive, has important therapeutic and management implications. Most ductal and lobular carcinomas are distinguished readily on hematoxylin-eosin-stained sections because of distinct histomorphologic features. In cases with ambiguous morphologic features, however, categorization in one or another type can be a challenge. Several immunohistochemical markers, including epithelial cadherin, p120, β-catenin, and low-molecular-weight and high-molecular-weight cytokeratins among others, have been introduced to help better discriminate between lobular neoplasia and ductal carcinoma. In this critical review of the literature, we comment about the usefulness and the limitations of these markers to improve the accuracy in the differential diagnosis of breast pathology.

Clinical implications of margin involvement by pleomorphic lobular carcinoma in situ

CONTEXT

The appropriate treatment for patients with pleomorphic lobular carcinoma in situ (PLCIS) is unknown. When diagnosed on core biopsy, excision is recommended; however, management of PLCIS when it involves margins has not been addressed.

OBJECTIVE

To evaluate the significance of PLCIS that is located close to, or at, a resection margin.

DESIGN

We identified 26 patients with resection specimens containing PLCIS, all of whom were offered chemoprevention and radiation therapy. The margin status in these patients was subdivided as PLCIS cells at the margin without obvious truncation of lesion; PLCIS less than or equal to 1 mm from, but not involving, the margin; PLCIS 1.1 to 2 mm from the margin; and PLCIS at least 2.1 mm from the margin.

RESULTS

Patient age ranged from 35 to 76 years (mean, 58 years), and length of follow-up ranged from 4 to 108 months (mean, 46 months). Six of the 26 patients (23%) received chemoprevention, 4 of 26 patients (15%) received radiation therapy, and 6 of 26 patients (23%) received both. The remaining 10 patients received no further therapy. Pleomorphic lobular carcinoma in situ was at the margin in 6 of the 26 cases (23%), 1 mm from the margin in 7 of 26 cases (27%), 1.1 to 2 mm from the margin in 4 of 26 cases (15%), and was at least 2.1 mm from the margin in 9 of 26 cases (35%). In 1 of the 26 patients, recurrent PLCIS was identified 18 months after initial surgery, for an overall recurrence rate of 3.8%. All other patients were clinically and radiologically free of disease at last follow-up.

CONCLUSIONS

This is the first series, to our knowledge, that evaluates margin status in patients with PLCIS and documents recurrence. Recurrent PLCIS was identified at a rate similar to low- or intermediate-grade ductal carcinoma in situ. Therefore, known methods of local control, including surgical excision with negative margins (2 mm), may be the appropriate treatment in these patients.

Amplification of the prolactin receptor gene in mammary lobular neoplasia

The identification of lobular carcinoma in situ (LCIS) in a patient's specimen confers an appreciable increased risk of development of future invasive mammary carcinoma. However, the study of LCIS presents a challenge as it is usually only recognized in fixed specimens. Recent advances in high throughput genomics have made possible comprehensive copy number analysis of lesions such as this. Using array comparative genomic hybridization (aCGH), we characterized eight cases of lobular carcinoma (four invasive and four non-invasive) from microdissected samples of archival specimens and validated our results by quantitative real-time PCR (qRT-PCR). Immunohistochemistry (IHC) was performed on an independent set of 80 in situ ductal (DCIS) and lobular breast lesions to confirm our results. Amplification of the prolactin receptor gene (PRLr) was identified in 4/4 cases of LCIS by aCGH. We confirmed this amplification by qRT-PCR and demonstrated PRLr expression in 29/40 (73%) cases of lobular neoplasia by IHC. Amplification of PRLr was neither detected in 10 cases of DCIS nor in 5 areas of normal breast tissue by qRT-PCR and only 14/40 (35%) cases of DCIS showed PRLr expression by IHC (P = 0.0008). Our study suggests the prolactin receptor gene is a molecular target that may be important in the pathogenesis and progression of lobular neoplasia. Investigation of the status of this gene in cases of DCIS has indicated that it may not be as important in the progression of this type of breast cancer, supporting the view that lobular and ductal carcinomas may evolve along separate pathways.

Invasive lobular carcinoma with extracellular mucin production and HER-2 overexpression: a case report and further case studies

Invasive lobular carcinomas (ILC) of breast typically demonstrate intracytoplasmic mucin. We present a unique case of classical type ILC with abundant extracellular mucin and strong ERBB2 (HER2/neu) expression confirmed by immunohistochemistry and fluorescent in situ hybridization. Dual E-cadherin/p120 immunohistochemical stain demonstrated complete loss of membranous E-cadherin and the presence of diffuse cytoplasmic p120 staining, confirming the lobular phenotype. The tumor cells showed ductal-like cytoplasmic MUC1 staining, but were negative for MUC2 and other mucin gene markers. In addition, studies of tissue microarrays of 80 breast carcinomas with mucinous differentiation revealed 4 pure mucinous carcinomas showing significantly reduced E-cadherin staining without redistribution of p120 into cytoplasm. The findings suggest that the presence of extracellular mucin does not exclude a diagnosis of lobular carcinoma, and the morphologic and molecular characteristics of lobular and ductal carcinomas are more complex than previously appreciated.

Lobular neoplasia: morphology, biological potential and management in core biopsies

Lobular neoplasia has been traditionally recognized as a marker of increased risk for subsequent breast carcinoma development; however, molecular studies suggest that it also behaves in a non-obligate precursor manner. We do not know, as yet, how to identify the subgroup of cases that is most likely to progress, but the epidemiological data would indicate that this progression occurs after a long period of time. Thus, the current approach of conservative management of these lesions when identified in excision specimens is justified. Recently, several variants of lobular carcinoma in situ (LCIS), most notably pleomorphic LCIS, have been recognized and these can be difficult to differentiate from ductal carcinoma in situ. Application of strict diagnostic criteria and the judicial use of immunohistochemistry, particularly E-cadherin, can be helpful in this differential diagnosis. Another challenging issue is the management of lobular neoplasia when diagnosed on core biopsy. This controversial issue will be discussed in detail. The goals of this review are (1) to describe the morphological criteria used to diagnose the spectrum of lobular neoplastic lesions, including atypical lobular hyperplasia, LCIS and variants of LCIS; (2) to discuss the data exploring the biological potential of lobular neoplasia from an epidemiological and molecular viewpoint; and (3) to outline the recommendations for management of lobular neoplasia when encountered in core biopsies.

Prognostic significance of fascin-1 and E-cadherin expression in laryngeal squamous cell carcinoma

Fascin-1 and E-cadherin, both of which are related to cell motility and cell adhesiveness, are important factors in the progression and metastasis of cancers. The objective of this study was to explore the association between fascin-1 and E-cadherin expression levels with both the clinical characteristics and prognoses of patients with laryngeal squamous cell carcinoma; we did so through statistical analyses. In our study, tumor tissue samples from 150 patients with laryngeal squamous cell carcinoma were examined for fascin-1 and E-cadherin expression by immunohistochemistry. Fascin-1 expression was found to be an independent predictive factor for recurrence in patients with laryngeal squamous cell carcinoma (P = 0.021) and independently related to disease-free survival (P = 0.010). Although E-cadherin expression status was not an independent predictive factor for recurrence (P = 0.055) or disease-free survival (P = 0.063), when using subgroup analysis, the subgroup with high fascin-1 expression/low E-cadherin expression had the poorest prognosis (P = 0.000). Fascin-1 expression could be a potential prognostic predictor for patients with laryngeal squamous cell carcinoma. Simultaneous analyses of fascin-1 and E-cadherin expression could be more effective in evaluating the prognoses of patients with laryngeal squamous cell carcinoma.

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.

Altered expression of p120catenin predicts poor outcome in invasive breast cancer

PURPOSE

The study focuses on p120catenin, a regulator of cell adhesion, which has previously been described in many malignancies and suggested with a role in invasion and metastatic behaviour. In this study, we investigate the role of altered immunoexpression of p120catenin isoforms in the prognosis of invasive breast cancer (n = 351).

METHODS

We used cDNA microarrays to screen differences in gene expression in invasive breast cancer in general, and between local and metastasized disease particularly. On this basis, we performed p120catenin immunohistochemistry in order to confirm the prognostic value of p120catenin isoforms on tissue microarrays comprising 341 patients from the era of mammographic screening, directed to modern surgical and oncological treatments, and followed-up for maximum of 20 years.

RESULTS

In cDNA microarray analysis, p120catenin was discovered down-regulated along with E-cadherin and alpha-catenin. In addition, p120catenin distinguished metastasized breast cancer from local disease. Immunohistochemistry confirmed the value of p120catenin as an independent prognosticator of breast cancer survival. In our results, p120catenin was associated with 3.7-fold risk of breast cancer death in multivariate Cox's regression analyses adjusted for the established prognosticators of breast cancer (p = 0.039). Particularly, the long isoform of p120catenin predicted metastatic disease (p = 0.029).

CONCLUSION

The present paper is the first report on p120catenin in invasive breast cancer based on a well-characterized patient material with long-term follow-up. We observed altered expression of p120catenin isoforms in invasive breast cancer and, in our material, the decrease in p120 immunoexpression was significantly associated with poor outcome of disease.

Pleomorphic lobular carcinoma of the breast: molecular pathology and clinical impact

Pleomorphic lobular carcinoma of the breast is a recently described morphological variant of classic invasive lobular carcinoma with an aggressive behavior. Morphologically, pleomorphic lobular carcinoma elicits a similar pattern of infiltrative growth as invasive lobular carcinoma, yet neoplastic cells have marked nuclear atypia and pleomorphism. Pleomorphic lobular carcinoma and the in situ counterpart, pleomorphic lobular carcinoma in situ, are frequently hormone receptor (estrogen-, progesterone- and androgen-receptor)-positive and E-cadherin and β-catenin-negative, attaining to their lobular nature. Tumors can also be positive for HER2, p53, ki67 and GCDFP-15 and harbor frequent chromosomal alterations involving gains on 1q and 16p, losses on 11q and 16q, and genomic amplifications in the region of 8q24, 11q13, 12q13, 17q12 and 20q13. Recent gene-expression profiling classified pleomorphic lobular carcinoma as ‘molecular apocrine’ tumors reflecting the frequent apocrine differentiation of the tumors. In support for the aggressive biological features described for pleomorphic lobular carcinoma, accumulating clinical data demonstrate that it has an aggressive clinical course. It is now important to define the most appropriate management strategy for patients diagnosed with pleomorphic lobular carcinoma.

Pleomorphic lobular carcinoma in situ (PLCIS) on breast core needle biopsies: clinical significance and immunoprofile

Pleomorphic lobular carcinoma in situ (PLCIS) is a more recently characterized entity that mimics high-grade ductal carcinoma in situ (DCIS). PLCIS is sometimes treated similar to high-grade DCIS, but no consensus has been reached for the most appropriate treatment. The aim of this study is to evaluate the histologic and immunohistologic profile of pure PLCIS on core needle biopsies and present follow-up clinical data. We reviewed 12 cases of pure PLCIS diagnosed on core needle biopsies of the breast along with subsequent surgical resections. Histologically, all cases showed dyscohesive cells with grade 3 nuclei, prominent nucleoli, and moderate to abundant eosinophilic cytoplasm. A panel of immunohistochemical stains to study this entity included E-cadherin, P120 catenin, estrogen receptor, progesterone receptors, HER2/neu, and Ki-67 (MIB-1). Residual PLCIS was found on excisional biopsies in 83% (10/12) cases. Invasive lobular carcinoma was found in 25% (3/12) cases. The lobular nature of all cases was confirmed by negative E-cadherin and cytoplasmic-dominant staining with P120 catenin. PLCIS was positive for estrogen receptor in 92% (11/12); progesterone receptor in 50% (6/12), and Her2/neu was positive in 25% (3/12). A moderate to high proliferation activity was observed with MIB (Ki-67) staining in 92% (11/12) cases. We conclude that PLCIS has a lobular immunostaining pattern for P120 catenin and E-cadherin indicating disruption of the E-cadherin/P120 catenin complex. This entity has aggressive parameters similar to high-grade DCIS including grade 3 nuclei, high Ki-67 (MIB-1) index, and HER2/neu positivity. PLCIS has a significant association with other high-risk lesions and invasive lobular carcinoma.

Serial analysis of gene expression of lobular carcinoma in situ identifies down regulation of claudin 4 and overexpression of matrix metalloproteinase 9

INTRODUCTION

Although lobular carcinoma in situ (LCIS) has traditionally been viewed as a marker of breast cancer risk, recent clinical, pathological and genetic analyses have supported the concept that LCIS is a low risk, direct precursor of invasive lobular carcinoma. Global gene expression profiling of LCIS has not been performed.

METHODS

We analysed the comprehensive gene expression profile of a unique case of mass-forming LCIS using serial analysis of gene expression (SAGE). This SAGE library is publicly available online. By comparing the gene expression profile of LCIS to that of benign breast epithelium and stroma, we identified several genes up and down regulated in LCIS. Differential expression of selected genes not previously studied in LCIS was validated at the protein level by immunohistochemistry and at the RNA level by quantitative reverse transcriptase PCR (RT-PCR).

RESULTS

We identified down regulation of claudin 4 and overexpression of matrix metalloproteinase 9 in LCIS relative to normal breast epithelium and stroma. We validated these findings by immunohistochemistry in a separate series of 11 and 19 LCIS cases, respectively. Overexpression of matrix metalloproteinase 9 was further confirmed by quantitative RT-PCR analysis of the index case.

CONCLUSIONS

We have created the first global gene expression profile of LCIS, and demonstrated down regulation of cell junction proteins (an expected result) and overexpression of matrix metalloproteinase 9 (an unexpected result). Additional analysis of this data made available as an online resource should facilitate further molecular characterisation of LCIS.

[Practical problems in breast screening. Columnar cell lesions including flat epithelial atypia and lobular neoplasia]

Columnar cell lesions (CCL) and lobular neoplasia (LN) are encountered with increasing frequency in breast screening biopsies. CCLs are frequently associated with microcalcifications, whereas LN is an incidental finding in most cases. Flat epithelia atypia (FEA) the atypical variant of CLL, LN and atypical ductal hyperplasia (ADH) are frequently associated lesions. Molecular genetic studies of CCL, ductal carcinoma in situ (DCIS) and low grade invasive carcinomas revealed similar chromosomal alterations supporting the assumption that CCLs are neoplastic proliferations. The frequent association of FEA together with well differentiated invasive carcinomas provides further evidence of this concept. There is no internationally accepted classification of CCLs at present. CDH1-gene mutations are the cardinal feature of LN and invasive lobular carcinoma. In immunohistochemically CDH1-positive cases, alternative genetic alterations of the CDH1 pathway can lead to functional loss of CDH1. In our opinion morphologically and immunohistochemically hybrid lesions may represent this group of lobular lesions. Recent follow-up data suggest a higher rate of ipsilateral carcinomas in patients with previously diagnosed LN. It is currently an open question whether FEA and LN are members of a common family of intralobular proliferations, which are non-obligatory precursors of a low nuclear grade breast neoplasia family.

Nuclear E-cadherin immunoexpression: from biology to potential applications in diagnostic pathology

E-cadherin is a well-recognized molecule that is important in cell adhesion. Its abrogation has been linked to increased invasiveness in several malignancies. The normal immunohistochemical localization of E-cadherin is the cell membrane, however, both cytoplasmic and nuclear immunostaining has been reported. Loss of membrane staining and/or nuclear staining for E-cadherin is seen in 100% of cases of solid pseudopapillary tumors (SPTs) of the pancreas. In the context of SPT, E-cadherin staining is of diagnostic use. Nuclear staining has been seen in cases of pancreatic neuroendocrine tumors, Merkel cell carcinomas, clear cell renal cell carcinoma, esophageal squamous carcinoma, colorectal and gastric cancer, and synovial sarcoma. The difference in the staining patterns seen (complete loss vs. nuclear staining) is due to the type of E-cadherin antibody used. Antibodies recognizing the extracellular domain show loss of E-cadherin staining in SPT, whereas the antibody to the cytoplasmic domain results in nuclear staining in all cases of SPT. Therefore, E-cadherin staining is of diagnostic use in the immunohistochemical work-up of SPT. Nuclear E-cadherin staining of pancreatic neuroendocrine tumors identified a subset of cases with more aggressive potential, whereas nuclear staining of clear cell renal cancers identified a subset of tumors with a better prognosis. The exact mechanism by which E-cadherin enters the nucleus is not known but it is likely that it is closely related to several partner molecules such as beta-catenin, p120, and presenilin-1.