The genomic profile of HER2-amplified breast cancers: the influence of ER status.

Expression profiling studies have suggested that HER2-amplified breast cancers constitute a heterogeneous group that may be subdivided according to their ER status: HER2-amplified ER-positive breast carcinomas that fall into the luminal B cluster; and HER2-amplified ER-negative cancers which form a distinct molecular subgroup, known as the erbB2 or HER2 subgroup. ER-negative breast cancer differs significantly from ER-positive disease in the pattern, type, and complexity of genetic aberrations. Here we have compared the genomic profiles of ER-positive and ER-negative HER2-amplified cancers using tiling path microarray-based comparative genomic hybridization (aCGH). Validation of the differentially amplified regions was performed in an independent series of 70 HER2-amplified breast cancers. Although HER2-amplified cancers had remarkably complex patterns of molecular genetic aberrations, ER-positive and ER-negative HER2-amplified breast carcinomas shared most molecular genetic features as defined by aCGH. Genome-wide Fisher's exact test analysis revealed that less than 1.5% of the genome was significantly differentially gained or lost in ER-positive versus ER-negative HER2-amplified cancers. However, two regions of amplification were significantly associated with ER-positive carcinomas, one of which mapped to 17q21.2 and encompassed GJC1, IGFBP4, TNS4, and TOP2A. Chromogenic in situ hybridization analysis of an independent validation series confirmed the association between ER status and TOP2A amplification. In conclusion, although hormone receptor status does not determine the overall genetic profile of HER2-amplified breast cancers, specific genetic aberrations may be characteristic of subgroups of HER2 breast cancers.

[Prognostic and predictive factors of invasive breast cancer: update 2009]. / Prognostische und prädiktive Faktoren invasiver Mammakarzinome: Update 2009.

Prognostic factors supply information on the course of a disease (recurrence-free and total survival) and are independent of the therapy. The most important prognostic factors are lymph node status, tumor diameter and histological differentiation stage, lymph and blood vessel invasion as well as staging, factors which can all be determined by pathologists. The Nottingham prognostic index (NPI) combines the strongest prognostic factors and according to study results is a suitable model for prognosis of breast cancer. Predictive factors give prior information on the probability of the response of a tumor to a defined therapy and include hormone receptor status, the invasion marker uPA/PAI-1, detection of isolated tumor cells, a residual tumor and the histological resection border.Prognostic or predictive factors are clinically relevant when therapy decisions are made possible by their recognition, which lead to an improvement in the total survival, recurrence-free survival or quality of life. The international consensus recommendation of St. Gallen 2007 requires the following as a basis for risk-adapted therapy decisions: tumor size, stage, age, nodal status, hormone receptor status and Her2 overexpression or amplification status.

[Anatomy of the breast]. / Anatomie der Brustdrüse.

The human breast consists of lobes with a luminal glandular and a basal myoepithelial layer. Immunofluorescence studies have shown that the breast epithelium contains cytokeratin (CK)5/14-positive precursor cells which give rise to CK8/18-positive glandular or sm-actin-positive myoepithelial cells. Only some of the glandular cells contain estrogen receptors. The luminal epithelium of the lobules shows a much higher glandular differentiation than the ductal system. Diagnostically important cytokeratins of normal breast epithelium and its proliferative epithelial processes include luminal cytokeratins (CK7, CK8 and CK18) as markers of glandular differentiation and basal cytokeratins (CK5, CK14 and CK17) as markers of progenitor cells and early cells of the glandular and myoepithelial differentiation pathway. The most important myoepithelial markers are currently CD10, SMA, SMM-HC and Calponin.

[Atypical ductal hyperplasia and atypical epithelial proliferation of ductal type]. / Atypische duktale Hyperplasie und atypische epitheliale Proliferation vom duktalen Typ.

The definition of atypical ductal hyperplasia (ADH) encompasses qualitative and quantitative criteria. Qualitative criteria include cytological and architectural features similar to those of low grade ductal carcinoma in situ (DCIS), the quantitative criteria are characterized by metric features (2 mm or 2 ductules) or by the confines of lobules. In this article we discuss the morphology of ADH, the status of ADH in the low grade pathway of breast carcinoma development and its clinical significance. Furthermore, we comment some special forms of atypical epithelial proliferations of the ductal type.

[Flat epithelial atypia]. / Flache epitheliale Atypie.

According to the WHO, flat epithelial atypia (FEA) is defined as a neoplastic epithelial proliferation of ductal type in either a single or in multiple terminal duct lobular unit(s) limited to the periphery of the ductules in a clinging growth pattern. The atypical cells may form between one and several layers of epithelial cells that show low grade cytologic atypia. FEA most often presents as mammographic microcalcifications, which are typically round (secretory type and psammomatous calcification in an eosinophilic matrix, so-called ossifying calcifications). Clinical relevance is dependent on whether the lesion appears in isolation or whether it is an excision biopsy or a minimally invasive biopsy. Currently available data suggest that the risk of subsequent breast carcinoma in the ipsilateral breast is very low following the diagnosis of FEA. The differential diagnosis should include atypical ductal hyperplasia, low-grade clinging ductal carcinoma in situ, blunt duct adenosis and apocrine metaplasia.

[Immunohistochemistry in breast pathology: differential diagnosis of epithelial breast lesions]. / Immunhistochemie in der Mammapathologie: Zur Differenzialdiagnose epithelialer Mammaläsionen.

Proliferative epithelial breast lesions include a wide variety of benign hyperplastic and noninvasive neoplastic lesions, as well as invasive carcinomas. Mammographically these lesions may show microcalcifications, architectural distortions or mass lesions. The task of the pathologist begins with a preoperative diagnosis by means of minimally invasive biopsy. His diagnosis forms the basis for not only the radiological-pathological correlation diagnosis, but also for the management of benign proliferative breast disease lesions, as well as therapeutic decisions in the case of malignant lesions.In daily practice, immunohistochemistry is the method of choice for clarifying difficult cases. The aim of this chapter is to describe the relevant markers in breast pathology and to provide an algorithmic approach to different proliferative breast disease lesions.

[Diagnostics of microcalcifications from minimally invasive biopsies in mammography screening: results from the prevalence phase]. / Mikrokalkdiagnostik an minimal-invasiven Biopsien im Mammographie-Screening: Ergebnisse aus der Prävalenzphase.

BACKGROUND: In mammography screening programmes carried out according to European guidelines, minimally invasive biopsies (MIB) are performed on up to 3% of participants. The aim of this study was to analyse the spectrum of histopathological findings including B categories in MIBs with microcalcifications compared to MIBs without microcalcifications. MATERIAL AND METHODS: Prospectively collected histological findings of MIBs taken during the period July 2006 to June 2007 were analysed using the Breast Screening Pathology Database of the Reference Centre in Münster. RESULTS: Of the 4,326 MIBs investigated, 2,161 were benign (B1-B3) whereas 2,165 were malignant (B4-B5) resulting in an overall malignancy rate of 50.04%. Of the MIBs 1,809 contained microcalcifications and 2,517 did not. Cases with microcalcifications showed a different distribution of B categories: B2 was found in 44.5% versus 24.2%, B3 in 18.2% versus 5.5% and the malignancy rate of cases with microcalcifications was 36.8% versus 59.5%. Of all cases of ductal carcinoma in situ (DCIS) detected in the screening programme, 83.35% were diagnosed in MIBs containing microcalcifications. CONCLUSIONS: MIBs containing microcalcifications showed a different spectrum of diagnoses, especially higher rates of B3 lesions. Even though MIBs without microcalcifications showed a higher overall malignancy rate, most cases of DCIS were diagnosed in MIB containing microcalcifications.

[Early loss of heterozygosity on chromosome arm 16q in flat epithelial atypia of the breast. Detection by microsatellite analyses]. / Früher Verlust der Heterozygotie auf Chromosomenarm 16q in flachen epithelialen Atypien der Brust. Detektion durch Mikrosatellitenanalysen.

With the improvement of breast carcinoma screening, pre-malignant cell lesions such as flat epithelial atypia (FEA) are detected more frequently. Several studies have demonstrated that FEA show features of a ductal neoplasia, but is it really a precursor lesion? We have started a comparative genetic analysis of a panel of nine microsatellite markers on six different chromosomal regions to investigate whether FEAs show the same characteristic genetic alterations as ductal carcinomas in situ (DCISs) and invasive carcinoma of the breast. FEAs, DCISs and invasive carcinomas of the same patients were microdissected using PALM micro laser technology. DNA was isolated using the QIAamp DNA Micro Kit (QIAGEN). We have investigated a set of the polymorphic microsatellite markers D7S522, D8S522, NEFL, D10S541 (PTEN), D13S153 (RB1), D16S400, D16S402, D16S422 and D17S855 (BRCA1) using multiplex PCR for the detection of allelic imbalances. Most of the investigated FEAs showed a lower frequency of loss of heterozygosity than associated DCISs or invasive carcinomas. However, we were able to detect the same alterations in FEAs as in DCISs or invasive carcinomas in a number of cases. Notably, the microsatellite marker on 16q showed more prevalent allelic imbalances in FEAs than the other investigated markers. One of the hallmarks in the pathogenesis of a large subgroup of invasive breast carcinomas is the early loss of chromosome arm 16q. In this study, we were able to detect frequent genetic alterations on chromosome 16q in FEAs, associated DCISs and invasive carcinomas. This suggests that FEA is a precursor lesion in the low-grade pathway.

Low prevalence of latently Epstein-Barr virus-infected cells in chronic gastritis.

The association of Epstein-Barr virus (EBV) with a proportion of gastric carcinomas is well established. The role of EBV in conditions predisposing to carcinoma such as chronic gastritis has remained undefined, however. We used in situ hybridization with radioactive and nonradioactive single-stranded RNA probes specific for the EBV small latent nuclear transcripts, EBER1 and EBER2, to analyze biopsy specimens from 242 patients with mild to severe chronic gastritis of Sydney classification types A, B, and C. A small number of EBV infected lymphocytes was detected in only nine cases, even in biopsies investigated with radioactive probes. Labeling of epithelial or stromal cells was not observed. The paucity of latently EBV-infected cells in chronic gastritis biopsies differs from the previously reported higher prevalence of virus carrying cells in inflammatory conditions at other sites of the gastrointestinal tract. These findings argue against a direct involvement of EBV in the pathogenesis of chronic gastritis. The low prevalence of EBV-positive cells suggests that local factors do not favor the entry and retention of circulating EBV-infected lymphocytes in gastric mucosa. Moreover, our findings indicate that EBV infection of gastric epithelial cells is not an early event in gastric carcinogenesis.

Minimal invasive biopsy results of "uncertain malignant potential" in digital mammography screening: high prevalence but also high predictive value for malignancy.

PURPOSE: To evaluate the rate, the histological spectrum and the positive predictive value (PPV) for malignancy of minimally invasive biopsies with "uncertain malignant potential (B3)" in digital mammography screening. METHODS AND MATERIALS: Consecutive data of 37,178 participants of one digital unit of the German screening program were included. RESULTS: The B 3 rate was 15.1 % (148 / 979). The frequencies of lesion subtypes were as follows: atypical epithelial proliferation of ductal type (AEPDT) 35.1 % (52 / 148), radial scar (RS) 28.4 % (42 / 148), papillary lesions (PAP) 20.3 % (30 / 148), lobular carcinoma in situ 8.8 % (13 / 148), flat epithelial atypia 5.4 % (8 / 148), and mucocele-like lesions 2.0 % (3 / 148). The PPV for malignancy in surgical excisions was overall 0.28 (25 / 91); in detail 0.40 (19 / 47) for AEPDT, 0.20 (5 / 25) for RS, 0.08 (1 / 12) for PAP. CONCLUSION: Despite a higher B 3 rate of minimally invasive biopsies with "uncertain malignant potential" in digital screening, the benign surgical biopsy rate is not disproportionally increased compared with analog screening programs. Together with defined management protocols, this results in an increased cancer detection rate per screening participant with surgical excision.

[The significance of "normal tissue" in the development of breast cancer: new concepts of early carcinogenesis]. / Bedeutung des "Normalgewebes" in der Brustkrebsentstehung: Neue Vorstellungen zur frühen Pathogenese des Mammakarzinoms.

Only little information on the primary molecularbiological events involved in early breast is available. In particular, the definition of postulated precursor lesions of invasive breast cancer, such as ductal hyperplasia or ductal carcinoma in situ, is under an intense, controversial discussion in terms of pathogenesis and tumor biology. The most recent research on biological regulation mechanisms and genetic alterations in morphologically normally appearing breast tissue give rise for a reinterpretation for the most common progression models of breast cancer. The detection of genetic alterations within normal breast tissue in particular challenges the commonly postulated relationship between invasive and in situ breast carcinomas on the one hand, and benign, proliferative breast lesions on the other. The concerns about these relationship are further supported by the description of different cellular compartments within the normal female breast, including a "progenitor cell compartment" with different cytokeratin expression patterns, which can be transferred towards well known or suspected precursor lesions of invasive and in situ breast cancer. The aim of this manuscript is to provide an overview of the most recent results and developments in breast pathology, and to describe the consequences of our changing understanding of breast carcinogenesis.

[Papillary tumors of the breast]. / Papilläre Tumoren der Mamma.

The term papilloma applies to benign proliferative epithelial breast lesions with a papillary architecture. The papillae in such lesions contain an arborizing fibrovascular core, glandular surface epithelium and a basal myoepithelial layer. A basement membrane encloses these structures. Papilloma may occur at any site in the ductal lobular system and according to its localization is subdivided into two types: solitary (central) papilloma which are located in the major nipple/subareolar ducts or large segmental ducts and multiple (peripheral) papillomas in cystically dilated terminal ductal lobular units (TDLU). Stromal changes, epithelial metaplasia and/or proliferations and neoplasia may alter the prototypical architecture. In a significant number of papillomas atypia can be identified which have to be classified as atypical proliferates of the ductal type. These lesions must be distinguished from the papillary type of ductal carcinoma in situ. Some 17% of all papilloma are associated with (synchronous) intraductal or invasive carcinoma, but these also act as an indicator for subsequent (metachronous) carcinoma. As a consequence, in minimally invasive biopsy papilloma has to be classified as B3 and usually has to be followed by surgical excision.

[Salivary duct carcinoma]. / Speichelgangkarzinome.

This tutorial focuses on salivary duct carcinoma (SDC), a rare, high grade neoplasm mainly of major salivary glands. The clinical course of these tumors is characterised by extended local disease, early distant metastasis, and poor outcome. The morphology of SDC is reminiscent of breast ductal carcinomas and may occasionally cause diagnostic problems. In spite of mimicry with ductal carcinoma in situ of the breast and an in situ component, that is evident in most tumors by immunohistology with antibodies directed against high molecular weight cytokeratins (Ck), SDC is always an invasive carcinoma. By immunohistology, most tumors show reactivity with antibodies directed against Ck 7, Ck 8/18 and Ck 19 whereas a morphologically indistinguishable subgroup expresses Ck 5/6 in tumor cells in addition to residual basal epithelia. Carcinoembryonic antigen, GCDFP-15 and androgen receptor are other helpful markers in routine diagnosis of SDC. Prostate-specific antigen is detectable in some cases. Abnormal p53 expression seems to indicate an adverse prognosis. Expression of c-erbB2, the over-expression of which is associated with a poor prognosis, may form the basis for a targeted therapeutic approach for selected cases of SDC.

[Myoepthelial tumors of salivary glands]. / Myoepitheliale Tumoren der Kopfspeicheldrüsen.

This tutorial focuses on myoepithelial tumors of salivary glands, an entity with heterogeneous cytomorphology and inconsistent immunophenotype. Moreover, the clinical course cannot be predicted reliably from cytomorphological and immunophenotypic analysis. This heterogeneity causes problems in routine diagnostic, so that diagnosis ultimately rests on conventional histology. In a representative series of myoepitheliomas and malignant myoepitheliomas, antibodies against cytokeratins 5/6, S 100 protein and vimentin produced the most consistent reactivity profile. Staining for cytokeratins 5/6 is a useful addition to the established immunohistologic marker panel in the work-up of myoepitheliomas, because of its reliable expression in most cases and because it may underline the epithelial nature of the lesion. Comparative genomic hybridisation (CGH) profiles of myoepitheliomas and myoepithelial carcinomas showed no chromosomal aberration in less than 50% of myoepithelial carcinomas, so that CGH is of limited help in a given case. In a case that was represented in three separately localized manifestations of the disease that differed in their CGH profiles, gross genetic aberrations suggest to be acquired during tumor progression and should raise the suspicion of malignancy. Thus, diagnosis of myoepithelial tumors of salivary glands has to rest on morphological grounds with support of a restricted panel of immunohistologic markers.