Correction to: Association of invasion-promoting tenascin-C additional domains with breast cancers in young women.

After the publication of this work [1] an error was noticed in Fig. 6 (b). In the MCF-7/Vector columns, the same image was used accidentally for the 0 h and 24 h time points. Both images were taken from the 0 h time point.

A Case-Matched Gender Comparison Transcriptomic Screen Identifies eIF4E and eIF5 as Potential Prognostic Markers in Male Breast Cancer.

Purpose: Breast cancer affects both genders, but is understudied in men. Although still rare, male breast cancer (MBC) is being diagnosed more frequently. Treatments are wholly informed by clinical studies conducted in women, based on assumptions that underlying biology is similar.Experimental Design: A transcriptomic investigation of male and female breast cancer was performed, confirming transcriptomic data in silico Biomarkers were immunohistochemically assessed in 697 MBCs (n = 477, training; n = 220, validation set) and quantified in pre- and posttreatment samples from an MBC patient receiving everolimus and PI3K/mTOR inhibitor.Results: Gender-specific gene expression patterns were identified. eIF transcripts were upregulated in MBC. eIF4E and eIF5 were negatively prognostic for overall survival alone (log-rank P = 0.013; HR = 1.77, 1.12-2.8 and P = 0.035; HR = 1.68, 1.03-2.74, respectively), or when coexpressed (P = 0.01; HR = 2.66, 1.26-5.63), confirmed in the validation set. This remained upon multivariate Cox regression analysis [eIF4E P = 0.016; HR = 2.38 (1.18-4.8), eIF5 P = 0.022; HR = 2.55 (1.14-5.7); coexpression P = 0.001; HR = 7.04 (2.22-22.26)]. Marked reduction in eIF4E and eIF5 expression was seen post BEZ235/everolimus, with extended survival.Conclusions: Translational initiation pathway inhibition could be of clinical utility in MBC patients overexpressing eIF4E and eIF5. With mTOR inhibitors that target this pathway now in the clinic, these biomarkers may represent new targets for therapeutic intervention, although further independent validation is required. Clin Cancer Res; 23(10); 2575-83. ©2016 AACR.

Current issues in diagnostic breast pathology.

On behalf of the NHS Breast Screening Programme Pathology Coordinating Group we present recommendations for terminology and diagnostic criteria for a number of key areas of practice in breast pathology where terminology can be confusing and where accurate communication will ensure appropriate clinical management. These recommendations cover columnar cell lesions and the spectrum of changes that can be seen in these epithelial proliferations, lobular neoplasia, micrometastases and isolated tumour cells in axillary lymph nodes, the use of basal/myoepithelial markers in diagnostic practice and oestrogen receptor testing in ductal carcinoma in situ.

Observer agreement comparing the use of virtual slides with glass slides in the pathology review component of the POSH breast cancer cohort study.

AIMS: (1) To compare the use of scanned virtual slide images (virtual microscopy) with glass slides (conventional microscopy) in the assessment of morphological characteristics of breast cancers within the setting of the Prospective study of Outcomes in Sporadic versus Hereditary breast cancer (POSH), involving a cohort of women under 40 years of age, presenting with breast cancer. (2) To assess the acceptability to histopathologists of the use of virtual slide images. METHODS: 13 histopathologists from the UK and Australia participated in the POSH pathology review. The observers were asked to assess multiple morphological features such as tumour grade and type. Comparisons were made for a single observer using both virtual images and glass slides. Intra- and inter-observer variability was calculated using the κ statistic and a comparison was made between the use of each image modality. RESULTS: Diagnostic performance with virtual slides was comparable to conventional microscopic assessment, with the measurement of agreement best for vascular invasion, necrosis and the presence of a central scar (κ=0.37-0.78), and poor for more subjective parameters such as pleomorphism, stroma, the nature of the tumour border and the degree of lymphocytic infiltrate (κ=0.1). CONCLUSION: Virtual slides represent an acceptable methodology for central review of breast cancer histopathology and can circumvent the need for either travel to view material, or the potential problems of sending it by post.

Genomic analysis of circulating cell-free DNA infers breast cancer dormancy.

Biomarkers in breast cancer to monitor minimal residual disease have remained elusive. We hypothesized that genomic analysis of circulating free DNA (cfDNA) isolated from plasma may form the basis for a means of detecting and monitoring breast cancer. We profiled 251 genomes using Affymetrix SNP 6.0 arrays to determine copy number variations (CNVs) and loss of heterozygosity (LOH), comparing 138 cfDNA samples with matched primary tumor and normal leukocyte DNA in 65 breast cancer patients and eight healthy female controls. Concordance of SNP genotype calls in paired cfDNA and leukocyte DNA samples distinguished between breast cancer patients and healthy female controls (P < 0.0001) and between preoperative patients and patients on follow-up who had surgery and treatment (P = 0.0016). Principal component analyses of cfDNA SNP/copy number results also separated presurgical breast cancer patients from the healthy controls, suggesting specific CNVs in cfDNA have clinical significance. We identified focal high-level DNA amplification in paired tumor and cfDNA clustered in a number of chromosome arms, some of which harbor genes with oncogenic potential, including USP17L2 (DUB3), BRF1, MTA1, and JAG2. Remarkably, in 50 patients on follow-up, specific CNVs were detected in cfDNA, mirroring the primary tumor, up to 12 yr after diagnosis despite no other evidence of disease. These data demonstrate the potential of SNP/CNV analysis of cfDNA to distinguish between patients with breast cancer and healthy controls during routine follow-up. The genomic profiles of cfDNA infer dormancy/minimal residual disease in the majority of patients on follow-up.

A comparative biomarker study of 514 matched cases of male and female breast cancer reveals gender-specific biological differences.

Male breast cancer remains understudied despite evidence of rising incidence. Using a co-ordinated multi-centre approach, we present the first large scale biomarker study to define and compare hormone receptor profiles and survival between male and female invasive breast cancer. We defined and compared hormone receptor profiles and survival between 251 male and 263 female breast cancers matched for grade, age, and lymph node status. Tissue microarrays were immunostained for ERα, ERß1, -2, -5, PR, PRA, PRB and AR, augmented by HER2, CK5/6, 14, 18 and 19 to assist typing. Hierarchical clustering determined differential nature of influences between genders. Luminal A was the most common phenotype in both sexes. Luminal B and HER2 were not seen in males. Basal phenotype was infrequent in both. No differences in overall survival at 5 or 10 years were observed between genders. Notably, AR-positive luminal A male breast cancer had improved overall survival over female breast cancer at 5 (P = 0.01, HR = 0.39, 95% CI = 0.26-0.87) but not 10 years (P = 0.29, HR = 0.75, 95% CI = 0.46-1.26) and both 5 (P = 0.04, HR = 0.37, 95% CI = 0.07-0.97) and 10 years (P = 0.04, HR = 0.43, 95% CI = 0.12-0.97) in the unselected group. Hierarchical clustering revealed common clusters between genders including total PR-PRA-PRB and ERß1/2 clusters. A striking feature was the occurrence of ERα on distinct clusters between genders. In female breast cancer, ERα clustered with PR and its isoforms; in male breast cancer, ERα clustered with ERß isoforms and AR. Our data supports the hypothesis that breast cancer is biologically different in males and females suggesting implications for clinical management. With the incidence of male breast cancer increasing this provides impetus for further study.

Clinical and functional significance of α9ß1 integrin expression in breast cancer: a novel cell-surface marker of the basal phenotype that promotes tumour cell invasion.

Integrin α9ß1 is a receptor for ECM proteins, including Tenascin-C and the EDA domain of fibronectin, and has been shown to transduce TGFß signalling. This study has examined the expression pattern of α9ß1 in 141 frozen breast carcinoma samples and related expression to prognostic indices, molecular subtype and patient outcome. Effects of α9ß1 on tumour cell migration and invasion were assessed using blocking antibody and gene transduction approaches. Integrin α9ß1 localized to myoepithelial cells in normal ducts and acini, a pattern maintained in DCIS. A subset (17%) of invasive carcinomas exhibited tumour cell expression of α9ß1, which related significantly to the basal-like phenotype, as defined by either CK5/6 or CK14 expression. Tumour expression of α9ß1 showed a significant association with reduced overall patient survival (p < 0.0001; HR 5.94, 95%CI 3.26-10.82) and with reduced distant-metastasis-free survival (p < 0.0001; HR 6.37, CI 3.51-11.58). A series of breast cancer cell lines was screened for α9ß1 with the highly invasive basal-like GI-101 cell line expressing significant levels. Both migration and invasion of this line were reduced significantly in the presence of α9-blocking antibody and following α9-knockdown with siRNA. Conversely, migratory and invasive behaviour of α9-negative MCF7 cells and α9-low MDA MB468 cells was enhanced significantly by over-expression of α9. Thus, α9ß1 acts as a novel marker of the basal-like breast cancer subtype and expression is associated with reduced survival, while its ability to promote breast cancer cell migration and invasion suggests that it contributes to the aggressive clinical behaviour of this tumour subtype.

Expression of tenascin-C and its isoforms in the breast.

Tenascin-C (TNC) is an extracellular matrix glycoprotein which is frequently up-regulated in a variety of pathological conditions including chronic inflammation and cancer. TNC has been implicated in the modulation of cell migration, proliferation, invasion and angiogenesis. Multiple isoforms of TNC can be generated through the alternative splicing of nine exons located in the fibronectin type III region of the molecule. The profile of isoforms expressed differs between cancers and normal breast, with the fully truncated TNC isoform being predominant in normal and benign tissues and higher molecular weight isoforms induced predominantly in cancer. The addition of extra domains within the fibronectin type III repeat domain greatly affects TNC function with multiple exon combinations available for splicing. Exons 14 and 16 are considered to be tumour-associated and have been shown to affect breast cell line invasion and growth in vitro to a greater extent than the full-length TNC isoform. This mini review will provide a summary of the literature to date regarding the expression of TNC isoforms in the breast and also discuss more recent developments in the field regarding exon AD1.

Association of invasion-promoting tenascin-C additional domains with breast cancers in young women.

INTRODUCTION: Tenascin-C (TNC) is a large extracellular matrix glycoprotein that shows prominent stromal expression in many solid tumours. The profile of isoforms expressed differs between cancers and normal breast, with the two additional domains AD1 and AD2 considered to be tumour associated. The aim of the present study was to investigate expression of AD1 and AD2 in normal, benign and malignant breast tissue to determine their relationship with tumour characteristics and to perform in vitro functional assays to investigate the role of AD1 in tumour cell invasion and growth. METHODS: Expression of AD1 and AD2 was related to hypoxanthine phosphoribosyltransferase 1 as a housekeeping gene in breast tissue using quantitative RT-PCR, and the results were related to clinicopathological features of the tumours. Constructs overexpressing an AD1-containing isoform (TNC-14/AD1/16) were transiently transfected into breast carcinoma cell lines (MCF-7, T-47 D, ZR-75-1, MDA-MB-231 and GI-101) to assess the effect in vitro on invasion and growth. Statistical analysis was performed using a nonparametric Mann-Whitney test for comparison of clinicopathological features with levels of TNC expression and using Jonckheere-Terpstra trend analysis for association of expression with tumour grade. RESULTS: Quantitative RT-PCR detected AD1 and AD2 mRNA expression in 34.9% and 23.1% of 134 invasive breast carcinomas, respectively. AD1 mRNA was localised by in situ hybridisation to tumour epithelial cells, and more predominantly to myoepithelium around associated normal breast ducts. Although not tumour specific, AD1 and AD2 expression was significantly more frequent in carcinomas in younger women (age ≤40 years; P < 0.001) and AD1 expression was also associated with oestrogen receptor-negative and grade 3 tumours (P < 0.05). AD1 was found to be incorporated into a tumour-specific isoform, not detected in normal tissues. Overexpression of the TNC-14/AD1/16 isoform significantly enhanced tumour cell invasion (P < 0.01) and growth (P < 0.01) over base levels. CONCLUSIONS: Together these data suggest a highly significant association between AD-containing TNC isoforms and breast cancers in younger women (age ≤40 years), which may have important functional significance in vivo.

Microglandular adenosis or microglandular adenoma? A molecular genetic analysis of a case associated with atypia and invasive carcinoma.

AIMS: Microglandular adenosis (MGA) is a rare breast lesion, which has long been considered to be hyperplastic. However, atypical forms of MGA (AMGA) and invasive carcinomas arising in the background of MGA are recorded. Recent studies have suggested that MGA may be a non-obligate precursor of invasive carcinomas that are negative for hormone receptors and lack HER-2 overexpression (triple-negative phenotype). The aim of this study was to determine whether MGA is clonal and whether it harbours chromosomal aberrations similar to those found in matched invasive ductal carcinoma of no special type (IDC-NST). METHODS AND RESULTS: We report on a case comprising MGA, AMGA and a high-grade IDC-NST. The three components were separately microdissected and subjected to genetic analysis with high-resolution microarray comparative genomic hybridisation. Identical genetic changes were detected in all components with subsequent acquisition of additional genetic aberrations in the invasive component, suggesting that MGA was the substrate for the development of the invasive carcinoma. Immunohistochemistry revealed concordant profiles across all components, characterized by triple-negative phenotype and variable positivity for basal markers. CONCLUSIONS: Similar to adenomas, MGA is, at least in some cases, a clonal lesion and may be a non-obligate precursor of a subgroup of high-grade triple-negative and basal-like breast carcinomas.

Tumour-associated tenascin-C isoforms promote breast cancer cell invasion and growth by matrix metalloproteinase-dependent and independent mechanisms.

INTRODUCTION: The stromal microenvironment has a profound influence on tumour cell behaviour. In tumours, the extracellular matrix (ECM) composition differs from normal tissue and allows novel interactions to influence tumour cell function. The ECM protein tenascin-C (TNC) is frequently up-regulated in breast cancer and we have previously identified two novel isoforms - one containing exon 16 (TNC-16) and one containing exons 14 plus 16 (TNC-14/16). METHODS: The present study has analysed the functional significance of this altered TNC isoform profile in breast cancer. TNC-16 and TNC-14/16 splice variants were generated using PCR-ligation and over-expressed in breast cancer cells (MCF-7, T47D, MDA-MD-231, MDA-MB-468, GI101) and human fibroblasts. The effects of these variants on tumour cell invasion and proliferation were measured and compared with the effects of the large (TNC-L) and fully spliced small (TNC-S) isoforms. RESULTS: TNC-16 and TNC-14/16 significantly enhanced tumour cell proliferation (P < 0.05) and invasion, both directly (P < 0.01) and as a response to transfected fibroblast expression (P < 0.05) with this effect being dependent on tumour cell interaction with TNC, because TNC-blocking antibodies abrogated these responses. An analysis of 19 matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinases 1 to 4 (TIMP 1 to 4) revealed that TNC up-regulated expression of MMP-13 and TIMP-3 two to four fold relative to vector, and invasion was reduced in the presence of MMP inhibitor GM6001. However, this effect was not isoform-specific but was elicited equally by all TNC isoforms. CONCLUSIONS: These results demonstrate a dual requirement for TNC and MMP in enhancing breast cancer cell invasion, and identify a significant role for the tumour-associated TNC-16 and TNC-14/16 in promoting tumour invasion, although these isoform-specific effects appear to be mediated through MMP-independent mechanisms.

Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion.

BACKGROUND: Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. METHODS: Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. RESULTS: Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). CONCLUSION: This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively.

The importance of careful blood processing in isolation of cell-free DNA.

In healthy individuals, the source of cell-free plasma DNA is predominantly apoptotic, whereas, increased plasma DNA integrity is seen in cancer patients. Therefore, it is important to carefully isolate absolutely "cell-free" plasma DNA. Plasma DNA from 30 healthy females was analyzed using 4 PCR amplicons of increasing size, comparing standard blood processing with additional centrifugation steps prior to DNA extraction. Cellular DNA contamination, indicated by positive amplicons >300 bp was eliminated only after the extra centrifugation step. This highlights the importance of careful processing in preparation of cell-free plasma DNA as a tool for cancer detection and we recommend the use of a microcentrifuge spin, prior to DNA extraction.

A multi-centre investigation towards reaching a consensus on the immunohistochemical detection of ERbeta in archival formalin-fixed paraffin embedded human breast tissue.

Estrogen receptor (ER) alpha is a well-established independent prognostic factor in breast cancer whose presence determines the clinical implications of adjuvant endocrine therapy. A second receptor, ERb has been described, and a number of studies have examined its expression in breast tissue. However elucidation of the role played by ERb has been hampered by published immunohistochemical studies employing a variety of protocols and scoring systems such that inter-laboratory comparisons are difficult. Here we present a multi-centre study designed to critically evaluate inter-laboratory differences in methodology. Six UK and Irish centres participated in this study. A small series of breast cancers were stained using centre-specific laboratory protocols and scored using both centrespecific and standard scoring protocols. There was generally poor agreement as to what constituted a positive or negative case when centre-specific scoring systems were used with less than half of all cases in agreement. Concordance was improved when a standard scoring system was used but varied according to threshold for positivity employed and primary antibody. Our results emphasise the need for further studies addressing the role of ERb to be based on a wider consensus on criteria for positivity. Ideally this should be based on calibration against clinical outcome.

Breast cell invasive potential relates to the myoepithelial phenotype.

On the basis of marker profile, the majority of breast carcinomas are thought to be derived from luminal epithelial cells; however, a subgroup of tumours with more mesenchymal characteristics are associated with a worse prognosis. The hypothesis of our study is that some breast carcinomas exhibit myoepithelial rather than pure mesenchymal differentiation and that acquisition of myoepithelial characteristics confers an aggressive phenotype. Pure luminal epithelial cells and fibroblasts are readily distinguished by many markers but distinguishing between myoepithelial and fibroblast cell lineages is more problematic. The markers found to be most discriminating in our study were CK14, alpha6beta4 integrin and the myoepithelial-associated desmosomal cadherin DSg3. These markers were applied to a series of breast cell lines and purified normal breast cell populations and the expression profile related to in vitro invasive behaviour. This demonstrated that expression of one or more myoepithelial markers by tumour cells (MDA MB 231, MDA MB 468, MDA MB 436) was associated with a high invasive capacity compared with cells with a pure luminal phenotype (MCF-7, T47D, ZR75). To address why myoepithelial characteristics are associated with higher invasion, the in vitro behaviour of normal myoepithelial cells and two other nontumourigenic breast cell lines (MCF-10A, HBL100) was also analysed. Primary myoepithelial cells from normal human breast exhibit a high invasive capacity when grown at low density, suggesting that invasive capacity is part of the myoepithelial phenotype. In keeping with this, both nontumourigenic cell lines exhibited features of the myoepithelial phenotype and a high invasive capacity. These results suggest that tumours that exhibit a myoepithelial phenotype may be clinically more aggressive because a high invasive capacity is intrinsic to the myoepithelial phenotype.

Oestrogen receptors alpha and beta differ in normal human breast and breast carcinomas.

The identification of a second oestrogen receptor, oestrogen receptor (ER) beta, has led to a need to assess the relative importance of the classical ERalpha and ERbeta in human breast and breast carcinomas. ERalpha and ERbeta mRNA was assessed in 61 carcinomas, 8 benign breast lesions, and 30 samples of normal breast using reverse transcriptase (RT)-nested polymerase chain reaction (PCR). Immunohistochemical analysis of ERalpha and ERbeta was performed in 62 carcinomas, the 38 non-malignant breast tissues, and 32 normal breast samples with menstrual cycle data. ERalpha mRNA was detected in 92% of breast cancers, with ERbeta mRNA (wild-type and/or variant form) in 85%; 72% had ERalpha protein, 62% progesterone receptor (PgR), and 32% ERbeta. ERalpha protein had a strong correlation with grade; ERbeta did not, although it was present in three of four grade I carcinomas and in special types. There was no correlation between the presence of ERalpha and ERbeta protein. In non-malignant breast, similar expression of ERalpha and beta was observed, apart from expression of ERbeta in stromal cells and myoepithelium, the latter being confirmed by RT-PCR and western blotting. There were differences in ERalpha in relation to the menstrual cycle but not PgR or ERbeta. The findings indicate a need to understand the role and regulation of ERbeta in normal breast and the reason for its down-regulation in mammary carcinogenesis.

Cyclooxygenase-2 expression is a novel prognostic factor in malignant mesothelioma.

Malignant mesothelioma (MM) is a fatal tumor of increasing incidence, which is resistant to current therapy. Cyclooxygenase-2 (COX-2) plays an important role in solid tumor growth, invasiveness, and angiogenesis, in part through the synthesis of prostaglandins such as prostaglandin E(2) (PGE(2)). In a prospective study, we evaluated COX-2 expression in snap-frozen, surgically resected MM tissue specimens using immunohistochemistry and semiquantitative Western blotting. PGE(2) was assessed by enzyme immunoassay. Thirty epithelioid, 10 biphasic, and 8 sarcomatoid tumors were evaluated. Immunohistochemistry demonstrated strong cytoplasmic tumor cell and variable stromal staining in all of the cases. COX-2 protein levels were correlated with clinicopathological prognostic factors using Kaplan-Meier and Cox proportional hazards models. High COX-2 band densitometry values correlated with poor survival (P = 0.008). In multivariate analysis, high COX-2 expression (P = 0.0005), nonepithelioid cell type (P = 0.002), and chest pain (P = 0.04) were independent predictors of poor prognosis. Furthermore, COX-2 expression contributed in multivariate analysis to both European Organization for Research and Treatment of Cancer (P = 0.001) and Cancer and Leukemia Group B (P = 0.003) prognostic scoring systems. The presence of PGE(2) was demonstrated in all of the samples. These results suggest that COX-2 expression is a prognostic factor in MM. COX-2 is a potential therapeutic target in MM, and trials are required of COX-2 inhibitors alone or in combination with existing treatment modalities.

Changes in tenascin-C isoform expression in invasive and preinvasive breast disease.

Tenascin-C (TN) is an extracellular matrix protein that is expressed at low levels in normal adult tissue but is highly expressed around many tumors including breast carcinoma. TN exists as multiple isoforms generated through alternative splicing, and these isoforms have different effects on cell growth and migration. This study has analyzed in detail the pattern of TN isoform expression in benign, preinvasive, and invasive breast lesions using reverse transcription-PCR and Southern blotting. Significant differences in the profile of TN isoforms were identified. Although all tissues expressed the fully truncated TN, expression of two additional isoforms, one containing exon 16 (TN16) and one containing both exons 14 and 16 (TN14/16), were significantly associated with the invasive phenotype (P < 0.001). A subset of ductal carcinoma in situ (DCIS) cases were also found to express these isoforms, which may be indicative of a high risk of invasion in these lesions. Expression of these isoforms correlated with the presence of TN protein in the stroma in place of or in addition to basement membrane TN. Immunohistochemistry and in situ hybridization confirmed the production of exon 14-containing higher molecular weight isoforms by stromal fibroblasts in malignant tissue and both periductal fibroblasts and residual myoepithelial cells in DCIS. Although no evidence of tumor cell synthesis of TN was detected in the tissues, two highly invasive breast cancer cell lines (MDA-MB 231 and MDA-MB 468) were found to produce TN in contrast with tumor cells with a lower invasive capacity (MCF-7 and T47D). These results demonstrate for the first time that specific TN isoforms are expressed in invasive breast carcinomas and that these isoforms are identified in a subset of DCIS and suggest that detection of TN16 and/or TN14/16 may be used as a predictor for invasion. Functional studies are now essential to establish the effect of these isoforms on tumor behavior and evaluate whether they will provide appropriate targets for therapeutic intervention.

[Immunohistochemical study of P-cadherin in breast cancer]. / P-cadherin immunhisztokémiai vizsgálata emlórákokban.

INTRODUCTION: Cell adhesion molecules play a significant role in the cellular connection of normal cells. The cadherins are believed to act as tumour suppressors, and their altered expression and function have been associated with tumour development. AIM AND METHODS: The authors examined the expression of a Ca++ dependent intercellular adhesion molecule, P-cadherin using an immunohistochemical method in 69 surgically resected breast carcinomas. RESULTS: P-cadherin was detected in 30 cases (43.5%, cytoplasmic and/or membrane staining). The expression of P-cadherin was independent of tumour size and lymph node status, but correlated with a high tumour grade (grade III). In contrast, expression of E-cadherin correlated with lower tumour grade (grade I-II). P-cadherin expression was not detected in invasive lobular carcinomas. CONCLUSION: In general, P-cadherin was expressed at a lower frequency compared to E-cadherin, alpha-, and beta-catenin. These results suggest that an inverse relationship may exist between E- and P-cadherin in relation to grade, and that the expression of P-cadherin may be a marker of aggressiveness.

Sporadic breast cancer in young women: prevalence of loss of heterozygosity at p53, BRCA1 and BRCA2.

Previous studies have shown that breast cancers have more aggressive pathologic features in young women. In order to examine genetic alterations associated with early-onset breast cancer, 31 patients with no known family history, aged 26-35 years at diagnosis, were examined for loss of heterozygosity (LOH) at 3 key chromosomal intervals: 17p (p53), 17q 21 (BRCA1) and 13q12-13 (BRCA2) using polymerase chain reaction analysis of polymorphic microsatellite markers. These were compared with 31 patients aged 55-72 years that were matched for size, type and grade. All young breast cancer cases exhibited LOH for at least 1 marker and 20 cases (64.5%) exhibited LOH at 1 or more markers from each interval. The frequency of LOH detected for each of the markers was as follows 17p: p534N (33.3%), D17S796 (36.7%), D17S799 (63.3%) and D17S513 (59.3%); 17q: D17S855 (64.5%), THRA1 (46.7%) and D17S579 (33.3%); and 13q: D13S260 (74.2%), D13S171 (47.6%) and D13S267 (40.0%). These frequencies are higher than those observed at the 3 markers studied in the matched postmenopausal patients: D17S799 (41.4%), D17S855 (35.5%), D13S260 (30.0%). These differences in frequency of LOH were statistically significant for the D17S855 and D13S260 markers (p < 0.025 and p < 0.001 respectively). Although there were more grade III carcinomas (21 of 31 cases), there was no correlation between number of alterations and high grade in younger cases. These data suggest that LOH at these regions could be related to early-onset sporadic breast cancer.