HER2 molecular subtype is a dominant subtype of mammary Paget's cells. An immunohistochemical study

Sek P, Zawrocki A, Biernat W & Piekarski J H
(2010) Histopathology 57 , 564–571
HER2 molecular subtype is a dominant subtype of mammary Paget’s cells. An immunohistochemical study Aims: To test the hypothesis that the similarity of the molecular subtypes of Paget’s cells to the molecular subtypes of the underlying breast carcinomas favours the epidermotrophic theory of the origin of Paget’s cells. Methods and results: The immunohistochemical expression of markers that define particular molecular subtypes of breast carcinomas were analysed. The whole analysis was performed by means of tissue microarrays in mammary Paget’s disease and in the underlying breast carcinoma(s). Human epidermal growth factor receptor type 2 (HER2)‐overexpression subtype [oestrogen receptor (ER^?); HER2⁺] was a dominant molecular subtype of Paget’s cells (37 of 43 analysed cases; 86%). Luminal B (ER⁺; HER2⁺) and luminal A (ER⁺; HER^?) subtypes were identified in 12% and 2% of cases, respectively. None of the analysed tumours presented a basal‐like phenotype. A similar distribution of molecular subtypes was identified in the underlying in situ breast carcinomas (HER2 subtype, 82%; luminal A, 6%; luminal B, 6%; basal‐like, 6% of cases) and in the invasive component (HER2 subtype, 84%; luminal A, 8%; luminal B, 8%; basal‐like, 0% of cases). Conclusions: HER2 molecular subtype is the dominant, but not the sole subtype seen in Paget’s cells of the nipple. A similar distribution of molecular subtypes in both Paget’s cells and in the underlying carcinomas strongly suggests their common origin.     

The expression and clinical significance of ribophorin II (RPN2) in human breast cancer

Ribophorin II (RPN2), part of the N‐oligosaccharyltransferase complex, is highly expressed in breast cancer stem cells and is associated with tumor metastasis through interaction with mutant p53. The clinicopathological implication of RPN2 expression is undetermined. We examined immunohistochemically the expression levels of RPN2 and p53 in primary breast cancer tissues surgically resected from 218 patients. The correlations of RPN2 expression with the intrinsic subtype defined by hormone receptors (HRs) and HER2, clinicopathological parameters, p53 expression, and patients’ clinical outcomes were examined. RPN2 was positive in 139 (64%), and the incidence of RPN2 expression was higher in the triple‐negative breast cancer (TNBC) (HR‐/HER2‐) (65%) and HER2‐enriched (HR‐/HER2+) subtype (95%) than in the luminal A‐like (HR+/HER2‐) subtype (58%) (P = 0.0009). RPN2 expression was also correlated with p53 nuclear accumulation (P = 0.04). The RPN2‐positive/p53‐positive patient group showed significantly poorer prognosis than the RPN2‐negative group for disease‐free survival (P = 0.05) and for overall survival (P = 0.02). By multivariate analyses, the combination of RPN2 and p53 was not an independent prognostic factor. RPN2 expression was correlated with clinically aggressive features of breast cancer. These data support the further clinical application of anti‐RPN2 therapy and the development of personalized medicine.     

Salivary duct carcinomas can be classified into luminal androgen receptor‐positive,HER2 and basal‐like phenotypes*

Di Palma S, Simpson R H W, Marchiò C, Skálová A, Ungari M, Sandison A, Whitaker S, Parry S & Reis‐Filho J S
(2012) Histopathology  61, 629–643 Salivary duct carcinomas can be classified into luminal androgen receptor‐positive, HER2 and basal‐like phenotypes Aims: The aim of this study was to devise a molecular classification for salivary duct carcinomas (SDCs) based on the similarities between SDCs and breast carcinomas and on characteristics of the microarray‐based gene expression profiling‐defined molecular subtypes of breast cancer. Methods and results: Forty‐two pure salivary duct carcinomas, 35 of which contained an in‐situ component as defined by histological review and/or immunohistochemical analysis, were stained with antibodies for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR) and cytokeratin (CK) 5/6. Based on these markers, tumours were classified into HER2, luminal androgen receptor‐positive, basal‐like, luminal and indeterminate phenotype. Analysis revealed that 16.7%, 69%, 4.8%, 9.5% and 0% were of HER2, luminal androgen receptor‐positive, basal‐like, indeterminate and luminal phenotype, respectively. The in‐situ and invasive components displayed the same molecular subtype in all but one case. Conclusions: Salivary duct carcinomas can be classified into molecular subgroups approximately equivalent to those in the breast. We also report on the existence of a subgroup of bona fide pure salivary duct carcinomas that have a ‘basal‐like’ phenotype. Understanding the phenotypic complexity of SDCs may help to expedite the identification of novel therapeutic targets for these aggressive tumours.     

Pleomorphic lobular carcinoma: a distinctive clinical and molecular breast cancer type

Monhollen L, Morrison C, Ademuyiwa F O, Chandrasekhar R, Khoury T
(2012) Histopathology  61, 365–377 Pleomorphic lobular carcinoma: a distinctive clinical and molecular breast cancer type Aims: Pleomorphic lobular carcinoma (PLC) is an aggressive variant of invasive lobular carcinoma. The aim of this study was to redefine PLC in terms of molecular classification. Methods and results: Cases of PLC were selected between 1995 and 2010. Key clinicopathological features were recorded for most of the patients. A panel of immunohistochemical stains including E‐cadherin, oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), cytokeratin (CK)5/6, CK14, CK17, anti‐cytokeratin (CAM) 5.2, CD117, vimentin, epidermal growth factor receptor (EGFR), p53 and gross cystic disease fluid protein‐15 (GCDFP‐15) were performed. HER2 test by fluorescence in‐situ hybridization (FISH) was also performed. The log‐rank test was used for statistical analyses. Forty cases fulfilled the criteria for PLC (26 with available tissue). The median age was 61 years and median tumour size was 2.0 cm. There were five of 38 (13.2%) triple‐negative cases. The basal type was seen in one of 25 cases (4%), which had a triple‐negative phenotype. HER2 was amplified in 14 of 38 cases (35%). Older patients and negative hormonal receptor status correlated significantly with worse clinical outcome (P < 0.03). The 5‐year recurrence‐free and overall survival was 54.9% and 76.2%, respectively. Conclusions: Pleomorphic lobular carcinoma is a distinctive breast cancer subtype. It has hybrid clinicopathological characteristics of ductal and lobular carcinoma.     

Expression of autophagy‐related markers beclin‐1, light chain 3A,light chain 3B and p62 according to the molecular subtype of breast cancer

Aims: To investigate the relationship between the expression of autophagy‐related proteins, including beclin‐1, light chain (LC) 3A, LC3B, and p62, and prognosis in invasive breast cancer. Methods and results: We constructed tissue microarrays from the breast cancer cells of 489 patients, and classified molecular subtypes using surrogate immunohistochemical stains. The tumoral expression levels of LC3A and LC3B were highest in triple‐negative breast cancer (TNBC) (P < 0.001), whereas these types of tumour had the lowest expression levels of these markers in the stroma (P = 0.005 and P < 0.001, respectively). Cytoplasmic beclin‐1 expression was highest in TNBC, but nuclear expression was lowest (P < 0.001). p62 cytoplasmic and nuclear expression were highest in HER2‐type tumours (P = 0.001 and P < 0.001, respectively). Tumoral LC3A and LC3B expression were associated with high histological grade (P < 0.001, and P < 0.028, respectively), but nuclear p62 expression was associated with lower histological grade (P = 0.004). Conclusions: Autophagy‐related markers are differentially expressed according to the molecular subtype of breast cancer. In particular, expression of LC3A, LC3B and beclin‐1 was highest in TNBC tumour cells, whereas that of LC3A and LC3B in the tumour stroma was lowest in TNBC.     

Mammary Stem Cells and Breast Cancer—Role of Notch Signalling

Adult stem cells are found in numerous tissues of the body and play a role in tissue development, replacement and repair. Evidence shows that breast stem cells are multipotent and can self renew, which are key characteristics of stem cells, and a single cell enriched with cell surface markers has the ability to grow a fully functional mammary gland in vivo. Many groups have extrapolated the cancer stem cell hypothesis from the haematopoietic system to solid cancers, where using in vitro culture techniques and in vivo transplant models have established evidence of cancer stem cells in colon, pancreas, prostate, brain and breast cancers. In the report we describe the evidence for breast cancer stem cells; studies consistently show that stem cell like and breast cancer initiating populations can be enriched using cell surface makers CD44⁺/CD24⁻ and have upregulated genes which include Notch. Notch signalling has been highlighted as a pathway involved in the development of the breast and is frequently dysregulated in invasive breast cancer. We have investigated the role of Notch in a pre-invasive breast lesion, ductal carcinoma in situ (DCIS), and have found that aberrant activation of Notch signalling is an early event in breast cancer. High expression of Notch 1 intracellular domain (NICD) in DCIS also predicted a reduced time to recurrence 5 years after surgery. Using a non-adherent sphere culture technique we have grown DCIS mammospheres from primary DCIS tissue, where self-renewal capacity, measured by the number of mammosphere initiating cells, were increased from normal breast tissue. A γ-secretase inhibitor, DAPT, which inhibits all four Notch receptors and a Notch 4 neutralising antibody were shown to reduce DCIS mammosphere formation, indicating that Notch signalling and other stem cell self-renewal pathways may represent novel therapeutic targets to prevent recurrence of pre-invasive and invasive breast cancer.     

Monocarboxylate transporter 1 is up‐regulated in basal‐like breast carcinoma

Pinheiro C, Albergaria A, Paredes J, Sousa B, Dufloth R, Vieira D, Schmitt F & Baltazar F
(2010) Histopathology 56, 860–867
Monocarboxylate transporter 1 is up‐regulated in basal‐like breast carcinoma Aims: Monocarboxylate transporters (MCTs) have been considered promising targets for cancer therapy, since they facilitate lactate efflux in glycolytic tumours. However, their role in solid tumours is still poorly understood. Thus, the present work aimed to contribute to understanding the involvement of MCT1 and MCT4 in breast cancer progression as well as MCT regulation by CD147. Methods and results: The expression of the membrane transporters MCT1 and MCT4 was analysed in a series of breast carcinomas (249 cases) and their clinicopathological significance investigated. Additionally, we analysed the significance of CD147 co‐expression, as an important regulator of MCT expression and activity. MCT1 was significantly increased in breast carcinomas when compared with normal breast tissue and, importantly, both MCT1 and CD147 were associated with poor prognostic variables such as basal‐like subtype and high grade tumours. Conclusions: These results provide evidence for a prognostic value of MCT1 in breast carcinoma and support the exploitation of the complex MCT1/CD147 as a promising target for cancer therapy, especially in basal‐like breast carcinoma.     

Identification of molecular phenotypes in canine mammary carcinomas with clinical implications: application of the human classification

Similarly to humans, canine mammary cancer represents a heterogeneous group in terms of morphology and biological behaviour. In the present study, we evaluated a series of canine mammary carcinomas based on a new human classification, initially based on gene expression profiling analysis. Similarly to human breast cancer, by using an immunohistochemistry surrogate panel based on five molecular markers [estrogen receptor, human epidermal growth factor receptor 2 (HER2), cytokeratin 5, p63 and P-cadherin], we were able to classify canine mammary carcinomas into four different subtypes: luminal A [estrogen receptor (ER)+/HER2-; 44.8%], luminal B (ER+/HER2+; 13.5%), basal (ER-/HER2- and a basal marker positive; 29.2%) and HER2 overexpressing tumours (ER-/HER2+; 8.3%). Luminal A-type tumours were characterised by lower grade and proliferation rate, whereas basal-type tumours were mostly high grade, high proliferative and positive for cytokeratin 5, p63 and P-cadherin. In addition, as in humans, basal subtype was significantly associated with shorter disease-free and overall survival rates, and we propose canine mammary carcinomas as a suitable natural model for the study of this particular subset of human carcinomas.     

Preserved Axin expression is associated with an aggressive phenotype in invasive breast carcinomas

Reduced Axin expression has been associated with an aggressive behavior in lung and esophageal squamous cell carcinomas. Its role in breast cancer has not been defined. The aim of our study was to investigate the expression pattern of Axin protein in invasive breast carcinomas, in relation to the behavior and prognosis of the disease. Immunohistochemistry was performed for the detection of Axin expression in 232 breast cancer tissues. Univariate and multivariate statistical analyses were used to assess the relation of Axin expression with classic clinicopathological parameters, patients' survival and various biologic markers Human Epidermal Factor‐2 (HER‐2), Ki‐67, topoIIα, glycogen synthase kinase‐3β (GSK‐3β)]. Preserved cytoplasmic Axin expression was positively correlated to lymph node invasion, HER‐2 and GSK‐3β and inversely to Ki‐67 and topoIIα. Nuclear Axin was positively associated with tumor size. Stromal Axin showed a parallel association with lymph node status and HER‐2. In the subgroup of lobular breast carcinomas, preserved Axin was found to exert an unfavorable impact on patients' overall survival. Our findings indicate, for the first time, that in invasive breast cancer preserved Axin expression is associated with a more aggressive phenotype and that in the discrete subtype of lobular breast carcinomas Axin negatively influences patients' overall survival.     

Determination of HER2 amplification in primary breast cancer using dual‐colour chromogenic in situ hybridization is comparable to fluorescence in situ hybridization: a European multicentre study involving 168 specimens

García‐Caballero T, Grabau D, Green A R, Gregory J, Schad A, Kohlwes E, Ellis I O, Watts S & Mollerup J
(2010) Histopathology 56, 472–480
Determination of HER2 amplification in primary breast cancer using dual‐colour chromogenic in situ hybridization is comparable to fluorescence in situ hybridization: a European multicentre study involving 168 specimens Aims: Fluorescence in situ hybridization (FISH) can be used to reveal several genomic imbalances relevant to proper cancer diagnosis and to the correct treatment regime. However, FISH requires expensive and advanced fluorescence microscopes in addition to expertise in fluorescence microscopy. To determine whether a newly developed dual‐colour chromogenic in situ hybridization (CISH) method is a suitable alternative to FISH, we analysed the human epidermal growth factor receptor 2 gene (HER2) amplification level of 168 breast cancer specimens using dual‐colour CISH and FISH and compared the results. Methods and results: We found 100% agreement between HER2 status determined by FISH and dual‐colour CISH. Furthermore, we observed that the time used to score slides was significantly reduced by 28% in dual‐colour CISH compared with the FISH protocol. Concordance between HER2 protein status and dual‐colour CISH or FISH was equally good with an overall agreement of 96.8%. Correlation between the HER2/centromere 17 gene ratios obtained with dual‐colour CISH and FISH was highly significant with an overall correlation coefficient (ρ) of 0.96. Conclusions: We conclude that dual‐colour CISH and bright field microscopy are excellent alternatives to FISH when analysing the HER2 status of primary breast cancer.     

Immunophenotyping of male breast cancer

Kornegoor R, Verschuur‐Maes A H J, Buerger H, Hogenes M C, de Bruin P C, Oudejans J J, Hinrichs B & van Diest P J
(2012) Histopathology
Immunophenotyping of male breast cancer Aims: Male breast cancer is a rare disease, and knowledge of carcinogenesis is limited. Conflicting results, based on small series, have been reported for clinically relevant biomarkers. Methods and results: One hundred and thirty‐four cases of male breast cancer were immunohistochemically stained on tissue microarrays for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor, human epidermal growth factor receptor 2 (HER2), BRST2, cyclin D1, bcl‐2, p53, p16, p21, Ki67, cytokeratin (CK) 5/6, CK14, and epidermal growth factor receptor. Data were correlated with clinicopathological features and patient outcome. High mitotic count and high grade were correlated with high Ki67, HER2 amplification/overexpression, p53 accumulation, high p21 expression, low PR expression, and low bcl‐2 expression. PR negativity (P = 0.009) and p53 accumulation (P = 0.042) were correlated with decreased 5‐year survival and were independent markers for patient outcome in Cox regression. In unsupervised hierarchical clustering, four groups were identified that were correlated with distinctive clinicopathological features. The hormone negative/ER‐positive/high‐grade cluster was significantly associated with decreased survival (P = 0.011) and was an independent prognostic factor in Cox regression. Conclusions: Several tissue biomarkers are associated with an aggressive phenotype in male breast cancer. PR and p53 are the most promising individual prognostic markers. On the basis of immunophenotype, four distinctive and prognostically relevant male breast cancer groups were identified, indicating that protein expression profiling may be clinically useful in male breast cancer.     

TopoⅡα在老年乳腺癌中的表达及其临床病理意义

目的对老年乳腺癌中TopoⅡα的表达与多个临床病理因素行相关性分析,探讨其表达的临床意义。方法应用免疫组化SP法检测南方医科大学附属南方医院近2年来所有老年乳腺癌共105例中TopoⅡα、ER、PR以及HER-2的表达情况;依据免疫组化的表达将其近似划分为LuminalA型(ER+和/或PR+,HER-2-)、LuminalB型(ER+和/或,PR+,HER-2+)、HER-2过表达型(ER-,PR-,HER-2+)和Basal-like型(ER-,PR-,HER-2-)4个分子亚型,对比TopoⅡα表达阳性率的差异。用统计学软件SPSS13.0作为统计分析的工具,TopoⅡα表达与临床病理因子的关系用卡方检验和Spearman相关分析检验。结果老年乳腺癌组织中TopoⅡα蛋白表达阳性率为62.9%,Basal-like型最高,HER-2过表达型仅次之,再次为LuminalB型,LuminalA型最低(P<0.050);阳性表达在不同组织学分期和淋巴结状态患者间差异中有统计学意义且呈正相关(P<0.050)。在不同肿瘤大小患者间差异无统计学意义。结论乳腺癌组织病理检查应根据ER、PR和HER-2的免疫组化结果行分子分型,进一步行TopoⅡα的免疫组化检测,以获得更多的预后信息,进一步指导老年乳腺癌治疗。     

Dual-colour chromogenic in-situ hybridization is a potential alternative to fluorescence in-situ hybridization in HER2 testing

Hwang C‐C, Pintye M, Chang L‐C, Chen H‐Y, Yeh K‐Y, Chein H‐P, Lee N & Chen J‐R
(2011) Histopathology 59 , 984–992 Dual‐colour chromogenic in‐situ hybridization is a potential alternative to fluorescence in‐situ hybridization in HER2 testing Aim: Dual‐colour chromogenic in‐situ hybridization (dc‐CISH) is an emerging methodology for characterizing genomic alterations. This study was aimed at evaluating the performance of a dc‐CISH kit (ZytoVision) in determining human epidermal growth factor receptor 2 (HER2) status in breast cancer. Methods and results: Two hundred and twenty‐eight invasive breast carcinomas arranged in tissue microarrays were analysed in parallel with dc‐CISH, fluorescence in‐situ hybridization (FISH), and immunohistochemistry. Of 227 tumours with available FISH and dc‐CISH results, HER2 amplification and non‐amplification were detected in 49 (21.6%) and 178 (78.4%) tumours, respectively, by both assays. The concordance between dc‐CISH and FISH results showed 100% agreement (κ‐coefficient = 1.00). Immunohistochemically, 162 (71%), 25 (11.0%) and 41 (18%) tumours were scored 0/1+, 2+, and 3+, respectively. The corresponding results with both FISH and dc‐CISH demonstrated HER2 amplification in two (3.2%), nine (36%) and 38 (93%) tumours, respectively. Complete consensus among these three methods was observed in 197 cases, representing 98% of all 3+ and 0/1+ tumours (κ‐coefficient = 0.92). Confirmatory testing of 25 2+ tumours showed complete consensus between FISH and dc‐CISH. Conclusions: dc‐CISH is a promising alternative to FISH in HER2 testing, and the single‐institute incidence of HER2 amplification in breast cancer in Taiwan is 21.2%.     

Announcements

Mohammed Z M A, Going J J, McMillan D C, Orange C, Mallon E, Doughty J C & Edwards J
(2012) Histopathology  61, 675–684 Comparison of visual and automated assessment of HER2 status and their impact on outcome in primary operable invasive ductal breast cancer Aims: To compare visual and computerized image analysis of HER2 immunohistochemistry (IHC) with fluorescence in‐situ hybridization (FISH) for HER2 status, and to examine the relationships with outcome in patients with primary operable invasive ductal breast cancer. Methods and results: Tissue microarrays for 431 breast cancer patients were used to compare different approaches to the assessment of HER2 status. The cores were scored visually and with the Slidepath Tissue IA system, using the NICE‐approved scoring system for the HercepTest, as well as by FISH. The agreement between visual and image analysis of HER2 IHC was excellent [interclass correlation coefficient (ICCC) = 0.95, r_s = 0.90, r = 0.91, k = 0.81, and P < 0.001]. The agreement of HER2 FISH with visual and image analysis of HER2 IHC was also excellent (ICCC = 0.95 and ICCC = 0.92, respectively). Univariate survival analysis showed equivalent associations of visual and image analysis of HER2 and HER2 FISH with both recurrence‐free survival (all P < 0.01) and cancer‐specific survival (all P < 0.05) in patients with invasive ductal breast cancer. Conclusions: Computerized image analysis of HER2 IHC gives results comparable to those obtained with visual assessment, with possible advantages in diagnostic pathology.     

Amplified in breast cancer 1 expression in breast cancer

Aims: The amplified in breast cancer 1 (AIB1), steroid receptor co‐activator family member, acts as an oestrogen receptor (ER) co‐activator. Acting with HER‐2, it is thought to play a role in endocrine resistance by facilitating ER–growth factor crosstalk. The aim was to analyse AIB1 expression by immunohistochemistry and study its correlations with other prognostic variables in breast cancer and its effect on survival. Methods: A tissue microarray comprising tumours from 438 patients with 15.4 years’ median follow‐up was used. Interpretable AIB1 expression obtained in 395 patients was analysed along with other prognostic factors in breast cancer. Results: AIB1 expression scores ranged from 0 to 30; positive AIB1 expression (score > 14) was seen in 146/395 breast cancers; it correlated negatively with ER (P = 0.003) and progesterone receptor (PR) (P = 0.007), and positively with HER‐2 (P = 0.005) and tumour grade (P = 0.014). It did not correlate with nodal status (P = 0.437). Among ER+ patients, AIB1 expression showed a trend towards loss of PR expression (29% versus 20%; P = 0.14). AIB1 did not predict survival on univariate or multivariate analysis. Conclusions: AIB1 expression correlates with HER‐2 expression in breast cancer and shows a trend of association with loss of PR expression in ER+ tumours. Our study supports the postulated role of AIB1 in ER–growth factor interactions.     

Cytoplasmic expression of high mobility group B1 (HMGB1) is associated with tumor‐infiltrating lymphocytes (TILs) in breast cancer

High mobility group box 1 (HMGB1) is a prototypic alarmin or damage‐associated molecule inducing inflammatory mediator release and immune response. Several studies have revealed the prognostic and predictive importance of tumor‐infiltrating lymphocytes (TILs) in breast cancer. The present study analyzed the expression of HMGB1 in each breast cancer subtype and the relationship between the expression level of HMGB1 and pathologic parameters including TILs. Two cohorts were studied: 575 consecutive breast cancer patients who underwent surgery between 1995 and 1998; and 767 triple negative breast cancer (TNBC) patients who underwent surgery between 2004 and 2010. The immunohistochemical expression level of HMGB1 in cytoplasm and nucleus was evaluated using tissue microarrays. High HMGB1 expression in cytoplasm was associated with high histologic grade, pT stage, and abundant TILs in the consecutive breast cancer cohort. Cytoplasmic HMGB1 expression was higher in TNBCs and HER2‐positive tumors than in hormone receptor‐positive tumors. In the TNBC cohort, high cytoplasmic HMGB1 expression was significantly associated with high histologic grade, abundant TILs, and high numbers of CD8+ cells. However, nuclear HMGB1 expression was not associated with histologic grade or TIL levels. Neither cytoplasmic nor nuclear expression of HMGB1 showed prognostic significance in TNBC. Cytoplasmic HMGB1 expression is associated with TIL levels in breast cancer.