Molecular subtyping of DCIS: heterogeneity of breast cancer reflected in pre-invasive disease

Extent of ductal carcinoma in situ according to breast cancer subtypes: a population-based cohort study

Ductal carcinoma in situ (DCIS) is a precursor of invasive breast carcinoma (IBC). The DCIS component is often more extensive than the invasive component, which affects local control. The aim of our study was to analyze features of DCIS within different IBC subtypes, which may contribute to the optimization of personalized approaches for patients with IBC. Patients with IBC reported according to the synoptic reporting module in the Netherlands between 2009 and 2015 were included. Data extraction included characteristics of the invasive component and, if present, several features of the DCIS component. Resection margin status analyses were restricted to patients undergoing breast-conserving surgery (BCS). Differences between subtypes were tested by a Chi-square test, spearman’s Rho test or a one-way ANOVA test. Overall, 36.937 cases of IBC were included. About half of the IBCs (n = 16.014; 43.4 %) were associated with DCIS. Her2+ IBC (irrespective of ER status) was associated with a higher prevalence of adjacent DCIS, a larger extent of DCIS and a higher rate of irradicality of the DCIS component as compared to ER+/Her2− and triple-negative subtypes (P < 0.0001 for all variables). The prevalence of DCIS in triple-negative IBC on the other hand was lowest. In this large population-based cohort study, we showed significant differences between the prevalence and extent of DCIS according to IBC subtypes, which is also reflected in the resection margin status in patients treated with BCS. Our data provide important information regarding the optimization of local therapy according to IBC subtypes.

Invasive ductal breast carcinoma with predominant intraductal component: Clinicopathological features and prognosis

PURPOSE

Invasive ductal carcinoma with predominant intraductal component (IDCPIC) represents almost 5% of breast cancers. Nevertheless few data exist concerning their characteristics and prognostic behaviour. Our objective was to describe IDCPIC's clinicopathological and prognostic features and compare them to that of invasive ductal carcinoma without predominant intraductal component (IDC).

METHODS

Retrospective single centre study including all the localized invasive ductal carcinoma listed in our institutional database. Clinical, radiological and pathological criteria were collected as well as disease-free survival (DFS) data.

RESULTS

From 1995 to 2008, 4109 invasive ductal breast cancers treated were included. Out of them 192 (4.7%) were IDCPIC. Most of IDCPIC (63%) were discovered by radiological screening whereas IDC suspicion was more often clinical (82.7% vs 49.5%, p < 0.001). Pathological lymph node involvement was less frequent in IDCPIC (35.8 vs 44.3%, p = 0.04). Invasive tumour median size was 2-fold smaller in IDCPIC (10 mm vs 20 mm, p<0.001). Hormone receptors expression was similar between both groups whereas HER2 overexpression was more frequent in IDCPIC (32% vs 14.3%, p<0.001). Mastectomy was more frequently performed for IDCPIC (67.7% vs 30.3%, p < 0.001) whereas chemotherapy and radiation therapy were less frequent (55.5% vs 68%, and 82.8% vs 95.5%, respectively, p < 0.001 for both). After matching for discriminant clinicopathological features (tumour size, lymph node involvement, vascular invasion, HER2), DFS was similar in both groups (5-year DFS of 87.4% vs 84.4%, p = 0.47).

CONCLUSION

IDCPIC and other IDC with invasive components showing similar clinicopathological features display a similar prognosis.

Cancer stem cells and early stage basal-like breast cancer

Ductal carcinoma in situ (DCIS) is a category of early stage, non-invasive breast tumor defined by the intraductal proliferation of malignant breast epithelial cells. DCIS is a heterogeneous disease composed of multiple molecular subtypes including luminal, HER2 and basal-like types, which are characterized by immunohistochemical analyses and gene expression profiling. Following surgical and radiation therapies, patients with luminal-type, estrogen receptor-positive DCIS breast tumors can benefit from adjuvant endocrine-based treatment. However, there are no available targeted therapies for patients with basal-like DCIS (BL-DCIS) tumors due to their frequent lack of endocrine receptors and HER2 amplification, rendering them potentially susceptible to recurrence. Moreover, multiple lines of evidence suggest that DCIS is a non-obligate precursor of invasive breast carcinoma. This raises the possibility that targeting precursor BL-DCIS is a promising strategy to prevent BL-DCIS patients from the development of invasive basal-like breast cancer. An accumulating body of evidence demonstrates the existence of cancer stem-like cells (CSCs) in BL-DCIS, which potentially determine the features of BL-DCIS and their ability to progress into invasive cancer. This review encompasses the current knowledge in regard to the characteristics of BL-DCIS, identification of CSCs, and their biological properties in BL-DCIS. We summarize recently discovered relevant molecular signaling alterations that promote the generation of CSCs in BL-DCIS and the progression of BL-DCIS to invasive breast cancer, as well as the influence of the tissue microenvironment on CSCs and the invasive transition. Finally, we discuss the translational implications of these findings for the prognosis and prevention of BL-DCIS relapse and progression.

Breast Tumor Heterogeneity: Source of Fitness, Hurdle for Therapy

Tumor heterogeneity impinges on prognosis, response to therapy, and metastasis. As such, heterogeneity is one of the most important and clinically relevant areas of cancer research. Breast cancer displays frequent intra- and inter-tumor heterogeneity as the result of genetic and non-genetic alterations that often enhance the vigor of cancer cells. In-depth characterization and understanding of the origin of this phenotypic and molecular diversity is paramount to improving diagnosis, the definition of prognostic and predictive biomarkers, and the design of therapeutic strategies. Here, we summarize current knowledge about sources of breast cancer heterogeneity, its consequences, and possible counter-measures. We discuss especially the impact on tumor heterogeneity of the differentiation state of the cell-of-origin, cancer cell plasticity, the microenvironment, and genetic evolution. Factors that enhance cancer cell vigor are clearly detrimental for patients.

Molecular classification of infiltrating breast cancer: toward personalized therapy

Breast cancer is a heterogeneous disease, which comprises several molecular and genetic subtypes, each with characteristic clinicobiologic behavior and imaging patterns. Traditional classification of breast cancer is based on the histopathologic features but offers limited prognostic value. Novel molecular characterization of breast cancer with cellular markers has allowed a new classification that offers prognostic value, with predictive categories of disease aggressiveness. These molecular signatures also open the door to personalized therapeutic options, with new receptor-targeted therapies. For example, invasive cancer subtypes such as the luminal A and B subtypes show better prognosis and response to hormone receptor-targeted therapies compared with the triple-negative subtypes; on the other hand, triple-negative tumors respond better than luminal tumors to chemotherapy. Tumors that display amplification of the oncogene ERBB2 (also known as the HER2/neu oncogene) respond to drugs directed against this oncogene, such as trastuzumab. The imaging aspects of tumors correlate with molecular subgroups, as well as other pathologic features such as nuclear grade. Smooth tumor margins at mammography may be suggestive of a triple-negative breast cancer, and a human epidermal growth factor receptor 2 (HER2)-positive tumor is characteristically a spiculated mass with calcifications. Low-grade ductal carcinoma in situ (DCIS) is better detected with mammography, although magnetic resonance (MR) imaging may allow better characterization of high-grade DCIS. MR imaging diffusion sequences show higher values for the apparent diffusion coefficient for triple-negative and HER2-positive subtypes, compared with luminal A and B tumors. MR imaging is also a useful tool in the prediction of tumor response after chemotherapy, especially for triple-negative and HER2-positive subtypes.

A Molecular Portrait of High-Grade Ductal Carcinoma In Situ

Ductal carcinoma in situ (DCIS) is a noninvasive precursor lesion to invasive breast carcinoma. We still have no understanding on why only some DCIS lesions evolve to invasive cancer whereas others appear not to do so during the life span of the patient. Here, we performed full exome (tumor vs. matching normal), transcriptome, and methylome analysis of 30 pure high-grade DCIS (HG-DCIS) and 10 normal breast epithelial samples. Sixty-two percent of HG-DCIS cases displayed mutations affecting cancer driver genes or potential drivers. Mutations were observed affecting PIK3CA (21% of cases), TP53 (17%), GATA3 (7%), MLL3 (7%) and single cases of mutations affecting CDH1, MAP2K4, TBX3, NF1, ATM, and ARID1A. Significantly, 83% of lesions displayed numerous large chromosomal copy number alterations, suggesting they might precede selection of cancer driver mutations. Integrated pathway-based modeling analysis of RNA-seq data allowed us to identify two DCIS subgroups (DCIS-C1 and DCIS-C2) based on their tumor-intrinsic subtypes, proliferative, immune scores, and in the activity of specific signaling pathways. The more aggressive DCIS-C1 (highly proliferative, basal-like, or ERBB2(+)) displayed signatures characteristic of activated Treg cells (CD4(+)/CD25(+)/FOXP3(+)) and CTLA4(+)/CD86(+) complexes indicative of a tumor-associated immunosuppressive phenotype. Strikingly, all lesions showed evidence of TP53 pathway inactivation. Similarly, ncRNA and methylation profiles reproduce changes observed postinvasion. Among the most significant findings, we observed upregulation of lncRNA HOTAIR in DCIS-C1 lesions and hypermethylation of HOXA5 and SOX genes. We conclude that most HG-DCIS lesions, in spite of representing a preinvasive stage of tumor progression, displayed molecular profiles indistinguishable from invasive breast cancer.

Expression of CD151/Tspan24 and integrin alpha 3 complex in aid of prognostication of HER2-negative high-grade ductal carcinoma in situ

The pro-tumorigenic and pro-metastatic functions of the tetraspanin protein CD151 (Tspan24) are thought to be dependent on its ability to form complexes with laminin-binding integrin receptors (i.e. alpha6beta1, alpha3beta1, alpha6beta4). We have previously reported that in invasive ductal carcinoma (IDC), CD151/alpha3beta1 complex was of prognostic value in patients with HER2-negative tumors. Extrapolating these findings to the pre-invasive setting, we aimed to make an assessment of a potential relationship between expression of the CD151/alpha3beta1 complex in DCIS and Van Nuys prognostic index (VNPI) in high-grade ductal carcinoma in situ (DCIS) in relation to the HER2 status. Protein distributions were analyzed in 49 samples of pure DCIS using immunohistochemistry. For each case immunoreactivity was assessed in at least 5 ducts (325 ducts in total) and an average score was taken for statistical analyses. When analyzed in the whole cohort, there was no statistical association between the VNPI and any of the proteins scored either separately or in combination. When stratified according to the HER2 status, in the HER2-negative subgroup, CD151 assessed in combination with alpha3beta1 was significantly correlated with VNPI (P = 0.044), while neither protein analyzed individually showed any significant link with the prognostic index. Expression of the CD151/alpha3beta1 complex in HER2-negative DCIS might reflect tumor behavior relevant to the patient outcome and thus might aid prognostication of the disease.

Immune microenvironment as a factor of breast cancer progression

Background

The rate of progression of the disease depends on various factors and the tumor microenvironment takes not the last place among them. One part of researchers argues that the presence of tumor-infiltrating leukocytes serves as a favorable marker of the disease. There exists a completely different point of view on the matter.

The investigation of the effects of the inflammatory infiltration on the course of breast cancer process.

Methods

We found a pronounced inflammatory infiltration in the tumor microenvironment in 24 cases. Nineteen cases of IDC without inflammatory infiltration were used as a control group. Immunohistochemical reaction showed expression of ERα, PR, HER2/neu, E-cadherin, Hsp90α, Bcl-2, CD3, CD79α, S100 and Myeloperoxidase receptors. Mathematical calculations were done using Microsoft Excel 2010 with 12.0.5 Attestat option.

Results

We have determined five variants of immune microenvironment: interstitial, trabecular, nodular, diffuse and mixed. We have established a direct correlation between the expression of ERα and PR and indirect correlation between the receptors of steroid hormones and HER2/neo in both groups of breast cancer. HER2/neo positive tumors in 100% of cases were accompanied by the presence of heat shock proteins. There was a combination of Bcl-2 presence with the steroid receptors expression in 90 % of cases. There was found the indirect correlation between the presence of B lymphocytes and expression of steroid receptors.

Conclusions

The presence of B lymphocytes in an inflammatory infiltrate leads to the disappearance of estrogen receptors and progesterone receptors. It provokes the accumulation of Hsp90 in a cell. It contributes to the stabilization of HER2/neu receptors and most proteins that promote tumor progression.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1362330168161694

Characteristics and behaviour of screen-detected ductal carcinoma in situ of the breast: comparison with symptomatic patients

Breast cancer is the most common malignancy in Singapore women. Ductal carcinoma in situ (DCIS) is the putative, non-obligate precursor of the majority of invasive breast cancers. The efficacy of the Singapore breast-screening pilot project in detecting early stage breast cancer led to the launch of a national breast-screening programme, BreastScreen Singapore (BSS), in January 2002. In this study, we compared clinicopathological and immunohistochemical characteristics, as well as clinical outcomes, between screen-detected and symptomatic DCIS. The study cohort comprised 1202 cases of DCIS diagnosed at Singapore General Hospital from 1994 to 2010. Comparison of clinicopathological parameters, immunohistochemical results of ER, PR, HER2, CK14, EGFR, and 34βE12, and clinical outcomes was carried out between the 2 groups. Amongst 1202 cases, 610 (50.7%) were screen-detected and 592 (49.3%) were symptomatic DCIS. Screen-detected cases were smaller in size (P < 0.001), of lower nuclear grade (P = 0.004), and more frequently expressed ER (P < 0.001). Luminal A phenotype was more frequently observed in screen-detected DCIS, while triple-negative and HER2 phenotypes were more common in symptomatic DCIS (P < 0.001). The basal-like phenotype was also more frequent in symptomatic DCIS (P = 0.041). Mean and median follow-up was 99.7 and 97.8 months, respectively, with a maximum follow-up of 246.0 months. More symptomatic patients developed invasive recurrences compared to screen-detected patients (P = 0.001). A trend for better disease-free survival was observed in screen-detected patients (P = 0.076). Patients who were screen-detected experienced better overall survival than those with symptomatic DCIS (P = 0.007). Our data indicate a more favourable outcome of screen-detected DCIS patients confirming the role of BSS in early identification of this curable disease.

The prognostic role of HER2 expression in ductal breast carcinoma in situ (DCIS); a population-based cohort study

Background

HER2 is a well-established prognostic and predictive factor in invasive breast cancer. The role of HER2 in ductal breast carcinoma in situ (DCIS) is debated and recent data have suggested that HER2 is mainly related to in situ recurrences. Our aim was to study HER2 as a prognostic factor in a large population based cohort of DCIS with long-term follow-up.

Methods

All 458 patients diagnosed with a primary DCIS 1986–2004 in two Swedish counties were included. Silver-enhanced in situ hybridisation (SISH) was used for detection of HER2 gene amplification and protein expression was assessed by immunohistochemistry (IHC) in tissue microarrays. HER2 positivity was defined as amplified HER2 gene and/or HER2 3+ by IHC. HER2 status in relation to new ipsilateral events (IBE) and Invasive Breast Cancer Recurrences, local or distant (IBCR) was assessed by Kaplan-Meier survival analyses and Cox proportional hazards regression models.

Results

Primary DCIS was screening-detected in 75.5 % of cases. Breast conserving surgery (BCS) was performed in 78.6 % of whom 44.0 % received postoperative radiotherapy. No patients received adjuvant endocrine- or chemotherapy. The majority of DCIS could be HER2 classified (N = 420 (91.7 %)); 132 HER2 positive (31 %) and 288 HER2 negative (69 %)). HER2 positivity was related to large tumor size (P = 0.002), high grade (P < 0.001) and ER- and PR negativity (P < 0.001 for both). During follow-up (mean 184 months), 106 IBCRs and 105 IBEs were identified among all 458 cases corresponding to 54 in situ and 51 invasive recurrences. Eighteen women died from breast cancer and another 114 had died from other causes. The risk of IBCR was statistically significantly lower subsequent to a HER2 positive DCIS compared to a HER2 negative DCIS, (Log-Rank P = 0.03, (HR) 0.60 (95 % CI 0.38–0.94)). Remarkably, the curves did not separate until after 10 years. In ER-stratified analyses, HER2 positive DCIS was associated with lower risk of IBCR among women with ER negative DCIS (Log-Rank P = 0.003), but not for women with ER positive DCIS.

Conclusions

Improved prognostic tools for DCIS patients are warranted to tailor adjuvant therapy. Here, we demonstrate that HER2 positive disease in the primary DCIS is associated with lower risk of recurrent invasive breast cancer.

Clinicopathologic characteristics and molecular subtypes of microinvasive carcinoma of the breast

Patients with microinvasive carcinoma often have favorable prognosis, but it remains unclear whether this special type of breast cancer represents a distinct morphological entity with its own biological features and clinical behavior distinct from those of ductal carcinoma in situ (DCIS). The study is a retrospective analysis of a large patient cohort from a single institution. One hundred and thirty one microinvasive carcinoma and 451 DCIS cases were collected. ER, PR, HER2, and Ki67 were examined by immunohistochemistry in pathological sections. We assessed the clinicopathologic characteristics, molecular features, and survival status of microinvasive carcinoma and compared to those of DCIS. Microinvasive carcinoma differed from DCIS with respect to tumor size, lymph node status, and initial presentation (P < 0.05). There was a significant difference in nuclear grade among microinvasive carcinoma of different molecular subtype (P < 0.05). The clinicalpathologic features and outcomes of patients with microinvasive carcinoma were similar to those with DCIS. The 5-year OS rate for microinvasive carcinoma and DCIS patients was 99.0 and 99.2%, respectively. A combination of pathologic, clinical, and molecular factors may ultimately reveal more powerful and robust measures for disease classification than any one modality alone. Microinvasive carcinoma does not significantly predict for worse DFS or OS in comparison with patients with DCIS.

Ductal carcinoma in situ of the breast: correlation between histopathological features and age of patients

Background

The histopathological subtype, nuclear grade and presence or absence of comedonecrosis are established as critical elements in the reporting of ductal carcinoma in situ (DCIS) of the breast. The aims of this study were to determine the frequencies of morphological subtypes of DCIS, nuclear grade and comedonecrosis; to compare the age of patients with the histopathological characteristics of DCIS, and to assess the agreement of grade between in situ and invasive components in DCIS cases that were associated with invasive carcinoma.

Methods

We evaluated a series of 403 cases of DCIS, pure or associated with invasive mammary carcinoma, consecutively identified from the histopathology files of the Breast Pathology Laboratory, Federal University of Minas Gerais, Brazil, from 2003 to 2008.

Results

DCIS displayed a single growth pattern in most cases (55.1%) and the solid subtype was the most common morphology (42.2% of the total). High-grade DCIS was identified in 293/403 cases (72.7%) and comedonecrosis was present in 222/403 cases (55%). Among DCIS with a single architectural pattern, high grade was more common in the solid subtype (151/168 cases, 89.9%; p < 0.001). Only 32% of tumours with a cribriform pattern had high nuclear grade. Comedonecrosis was more common in the solid morphology than in the cribriform, papillary and micropapillary subtypes (p < 0.001). Patients with high-grade DCIS were younger in relation to patients with low-grade DCIS (p = 0.027) and patients with tumours with comedonecrosis were also younger in comparison to patients with tumours without comedonecrosis (p = 0.003). Fair agreement was observed between in situ and invasive components with regard to grade (weighted kappa = 0.23).

Conclusions

The high nuclear grade and the presence of comedonecrosis were identified more frequently in younger patients and more often correlated with the solid pattern of DCIS.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_227

Molecular Markers as Prognostic Factors in DCIS and Small Invasive Breast Cancers

Ductal carcinoma in situ (DCIS) accounts for up to half of screen-detected breast cancers and thus constitutes a major public health problem. Despite effective current treatment many patients with DCIS are either over- or undertreated because of the paucity of precise models to predict recurrence or progression. The combination of clinical and molecular factors as already applied for invasive disease may help to build such models also for DCIS. We compared 53 DCIS (36.6 %) and 92 (63.4 %) invasive breast cancer cases and found no significant differences in age, receptor status of ER, PR, and HER2, and the use of radiotherapy. Interestingly, the proportion of disseminated tumor cells (DTC) did also not significantly differ between DCIS and invasive cases (p = 0.57). A negative PR status was associated with the detection of DTCs (p = 0.026). We then compared relationships of clinical parameters and biomarkers with patients' prognosis in 43 DCIS and 40 small invasive tumors ≤ 5 mm (T1a). ER negativity was associated with shorter relapse free survival in the complete cohort (p = 0.004) and showed a trend in both subgroups (p = 0.053 for DCIS and p = 0.046 for T1a, respectively). In conclusion, we found markedly similar properties of both DCIS and small invasive breast cancers with respect to the distribution of several parameters as well as to the prognostic value of biomarkers. DCIS with a luminal phenotype seem to be characterized by a favourable prognosis.

Methylation profiling of ductal carcinoma in situ and its relationship to histopathological features

Introduction

DNA methylation is a well-studied biomarker in invasive breast cancer, but its role in ductal carcinoma in situ (DCIS) is less well characterized. The aims of this study are to assess the methylation profile in DCIS for a panel of well-characterized genes that are frequently methylated in breast cancer, to investigate the relationship of methylation with pathological features, and to perform a proof-of-principle study to evaluate the practicality of methylation as a biomarker in diagnostic DCIS material.

Methods

Promoter CpG island methylation for a panel of 11 breast cancer-related genes was performed by methylation-sensitive high resolution melting (MS-HRM). Formalin-fixed, paraffin-embedded (FFPE) biopsies from 72 samples of pure DCIS (DCIS occurring in the absence of synchronous invasive carcinoma), 10 samples of mixed DCIS (DCIS adjacent to invasive carcinoma), and 18 samples of normal breast epithelium adjacent to a DCIS lesion were micro-dissected prior to DNA extraction.

Results

Methylation was seen for all the tested genes except BRCA1. RASSF1A was the most frequently methylated gene (90% of DCIS samples) and its methylation was associated with comedo necrosis (p = 0.018). Cluster analysis based on the methylation profile revealed four groups, the highly methylated cluster being significantly associated with high nuclear grade, HER2 amplification, negative estrogen receptor (ER) α status, and negative progesterone receptor (PgR) status, (p = 0.038, p = 0.018, p <0.001, p = 0.001, respectively). Methylation of APC (p = 0.017), CDH13 (p = 0.017), and RARβ (p <0.001) was associated with negative ERα status. Methylation of CDH13 (p <0.001), and RARβ (p = 0.001) was associated with negative PgR status. Methylation of APC (p = 0.013) and CDH13 (p = 0.026) was associated with high nuclear grade. Methylation of CDH13 (p = 0.009), and RARβ (p = 0.042) was associated with HER2-amplification.

Conclusions

DNA methylation can be assessed in FFPE-derived samples using suitable methodologies. Methylation of a panel of genes that are known to be methylated in invasive breast cancer was able to classify DCIS into distinct groups and was differentially associated with phenotypic features in DCIS.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0423-9) contains supplementary material, which is available to authorized users.

Increased Likelihood of Mastectomy in Human Epidermal Growth Factor Receptor 2-positive Ductal Carcinoma In Situ

Patients with human epidermal growth factor receptor 2 (HER2neu)-positive breast invasive cancer are known to have larger, more aggressive tumors. Little research exists on the relationship between HER2neu status and extent of ductal carcinoma in situ (DCIS). A retrospective review of a single-institution database was performed for patients with DCIS between the years 2002 and 2011. A single blinded breast radiologist reviewed preoperative imaging. Pathology was reviewed for extent of DCIS. Primary outcome was mastectomy. Multivariate logistic regression was used to determine adjusted mastectomy risk. There were 166 cases, 34 HER2neu-positive. HER2neu receptor-positive patients had larger lesions on imaging: 4.0 versus 2.7 cm, by 2.9 versus 1.5 cm ( P = 0.0499 and 0.0182). HER2neu-positive patients with DCIS were more likely than HER2neu-negative to undergo mastectomy than lumpectomy (53 vs 28%, P = 0.006). Pathology revealed a trend toward larger lesions in HER2neu-positive patients (2.96 vs 2.22 cm, nonsignificant). Patients with HER2neu-positive disease were three times more likely to undergo mastectomy (odds ratio, 2.9; 95% confidence interval, 1.23 to 6.78). Patients with HER2neu-positive DCIS had greater extent of disease by imaging and were more likely to undergo mastectomy than HER2neu-negative. These findings will help surgeons counsel patients on surgical treatment.

Identifying a highly-aggressive DCIS subgroup by studying intra-individual DCIS heterogeneity among invasive breast cancer patients

The heterogeneity among multiple ductal carcinoma in situ (DCIS) lesions within the same patient also diagnosed with invasive ductal carcinoma (IDC) has not been well evaluated, leaving research implications of intra-individual DCIS heterogeneity yet to be explored. In this study formalin-fixed paraffin embedded sections from 36 patients concurrently diagnosed with DCIS and IDC were evaluated by immunohistochemistry. Ten DCIS lesions from each patient were then randomly selected and scored. Our results showed that expression of PR, HER2, Ki-67, and p16 varied significantly within DCIS lesions from a single patient (P<0.05 for PR; P<1×10⁻⁸ for HER2, Ki-67 and p16). In addition, seventy-two percent of the individuals had heterogeneous expression of at least 2/6 markers. Importantly, by evaluating the expression of promising DCIS risk biomarkers (Ki-67, p53 and p16) among different DCIS subgroups classified by comparing DCIS molecular subtypes with those of adjacent normal terminal duct lobular units (TDLU) and IDC, our results suggest the existence of a highly-aggressive DCIS subgroup, which had the same molecular subtype as the adjacent IDC but not the same subtype as the adjacent normal TDLU. By using a systematic approach, our results clearly demonstrate that intra-individual heterogeneity in DCIS is very common in patients concurrently diagnosed with IDC. Our novel findings of a DCIS subpopulation with aggressive characteristics will provide a new paradigm for mechanistic studies of breast tumor progression and also have broad implications for prevention research as heterogeneous pre-invasive lesions are present in many other cancer types.

Histopathological characterization of ductal carcinoma in situ (DCIS) of the breast according to HER2 amplification status and molecular subtype

This study aimed to characterize ductal carcinoma in situ (DCIS) according to human epidermal growth factor receptor 2 (HER2) amplification status and molecular subtype. In addition, we performed a detailed HER2 and CEP17 copy number analysis and we assessed the impact of recent changes in the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines on HER2 immunohistochemical (IHC) scores in DCIS. Nuclear grade, extensive comedonecrosis, stromal architecture, stromal inflammation, and progesterone receptor (PR) expression were significantly associated with HER2 amplification status. In multivariate analysis, stromal inflammation and extensive comedonecrosis were the only two features that remained significantly related to HER2 amplification status. The recent changes in ASCO/CAP guidelines resulted in significant upgrading of HER2 IHC score. Remarkably, about one in five non-amplified DCIS presented a 3+ IHC score, regardless of the scoring method. The biological significance of this phenomenon is presently unknown. After categorization according to molecular subtype, luminal A DCIS mainly presented histopathological features associated with good prognosis, whereas luminal B/HER2+ and HER2+ categories displayed a more aggressive phenotype. Overall, our results demonstrate that HER2-amplified DCIS constitute a clearly distinct subgroup which is characterized by histopathological features associated with poor prognosis. Further studies are required to elucidate the biological significance of a 3+ IHC score in non-amplified DCIS, as well as its mechanism.

A model of immunohistochemical differences between invasive breast cancers and DCIS lesions tested on a consecutive case series of 1248 patients

BACKGROUND

A previous theoretic model (Tumour Biol 2013;34:1-7.) that breast tumor types differ in the relative rate of tissue invasion was elaborated and developed on a consecutive case series.

METHOD

Histologic data of 68 ductal breast cancer in situ (DCIS) and 1180 invasive ductal cancer (IDC) patients were collected and analyzed.

RESULTS

ER+PgR- phenotype was more common in Luminal B2 than among the pooled Luminal A&B1 (p = 0.0002), and more frequent in Luminal B1 than in Luminal A (p = 0.0167). The same phenotype was associated with the age older than 54 years in Luminal B1 and in B2 patients. HER2 type cancers were more frequent in older patients (p = 0.0038).Tumor progression from DCIS to IDC was found 39% faster than the average in Luminal B1 tumors, supporting the clinical importance of this tumor type. A rare combination of low Ki-67 in HER2 type cancers (only 14% of HER2 type cancers) showed very slow transition to IDC (occurring at only 53.55% of average progression rate), while triple-negative cancers progressed faster than the average, despite Ki-67 value (104.63% for low and 114.27% for high Ki-67 tumors).In three tumor types with positive steroid receptors the ER+PgR- phenotype showed slower IDC transition than the ER+PgR+ phenotype of the same tumor type (difference in progression rate was 38% for Luminal A, 46% for Luminal B1 and 67% for Luminal B2 with Ki67 > 14%).Triple-negative tumors in younger patients exceeded the expected average progression rate by 24%, while in HER2 type tumors, the rate of tissue invasion was in younger patients 20% lower than the expected value.

CONCLUSIONS

The relative rate of tissue invasion differed substantialy among our patients. Differences depended on tumor types, steroid expression phenotypes and age. The dysfunctional ERs in the ER+PgR- phenotype showed slower rates of tissue invasion, suggesting that ligand binding to functional breast tumor ERs, beside promoting the PgR expression, possibly also promotes tumor transition to the invasive phase.In triple-negative tumors, an age dependent premenopausal mechanism possibly acted as an accelerator of tissue invasion, while faster tissue invasion by HER2-overexpressed tumors in older patients possibly depended on an unidentified mechanism that takes more time to be acquired, so it was less present in premenopausal patients.

Narrowing down the focus: what are the main predictive markers for ductal carcinoma in situ?

SUMMARY 

Ductal carcinoma in situ accounts for approximately a quarter of newly diagnosed breast cancer nowadays. It is not life threatening per se, but confers an increased risk for subsequent invasive cancers. Optimal management should be based on the tumor characteristics and tailored to the risk of subsequent recurrence and invasive events. Prediction for recurrence risk has been determined mainly with clinical and histopathologic factors. However, they are imperfect, probably owing to the lack of standardized methods for assessment. Ongoing efforts have been shifted to the use of molecular factors, as well as prediction of noninvasive and invasive recurrences separately. These molecular factors seem to be more powerful in predicting invasive and noninvasive recurrence. However, their emerging roles still need to be validated.

Ductal carcinoma in situ: an overview

Advances in methods used to diagnose breast cancer have resulted in the increased detection of ductal carcinoma in situ; most of these are detected by screening mammograms and are confirmed by core needle biopsy. Currently, classification schemas are moving toward a molecular approach. Treatment options for patients with ductal carcinoma in situ are multiple and take into consideration end points such as local, regional or distant recurrence, overall survival and quality of life. Treatment methods continue to be controversial and debated in the oncology community. The quality of local control is multifactorial and depends on adequate surgical clearance, biological characteristics of the tumor, clinical presentation and the possibility of radiation therapies.

A nation-wide multicenter retrospective study of the epidemiological, pathological and clinical characteristics of breast cancer in situ in Chinese women in 1999 - 2008

BACKGROUND

Compared with invasive breast cancer, breast cancer in situ (BCIS) is seldom life threatening. However, an increasing incidence has been observed in recent years over the world. The purpose of our study is to investigate the epidemiological, clinical and pathological profiles of BCIS in Chinese women from 1999-2008.

METHODS

Four thousand and two hundred-eleven female breast cancer (BC) patients were enrolled in this hospital-based nation-wide and multi-center retrospective study. Patients were randomly selected from seven hospitals in seven representative geographical regions of China between 1999 and 2008. The epidemiological, clinical and pathological data were collected based on the designed case report form (CRF).

RESULTS

There were one hundred and forty-three BCIS cases in four thousand and two hundred-eleven BC patients (3.4%). The mean age at diagnosis was 48.3 years and BCIS peaked in age group 40-49 yrs (39.9%). The most common subtype was ductal carcinoma in situ (DCIS) (88.0%). 53.8% were positive for estrogen receptor (ER). Human epidermal growth factor receptor 2 (HER2) positive status was observed in 23.8% of patients. All patients underwent surgeries and 14.7% of them had breast conservation therapies (BCT) (21/143), but 41.9% accepted chemotherapy (64/143). Much less patients underwent radiotherapy (16.0%, 23/143) and among patients who had BCT, 67% accepted radiotherapy (14/21). Endocrine therapy was taken in 44.1% patients (63/143).

CONCLUSIONS

The younger age of BCIS among Chinese women than Western countries and increasing number of cases pose a great challenge. BCT and endocrine therapy are under great needs.

Altered microenvironment promotes progression of preinvasive breast cancer: myoepithelial expression of αvβ6 integrin in DCIS identifies high-risk patients and predicts recurrence

PURPOSE

This study investigated the functional and clinical significance of integrin αvβ6 upregulation in myoepithelial cells of ductal carcinoma in situ (DCIS).

EXPERIMENTAL DESIGN

Archival samples of DCIS and DCIS with associated invasion (n = 532) were analyzed for expression of αvβ6 by immunohistochemistry and ability to predict recurrence and progression assessed in an independent, unique cohort of DCIS cases with long-term follow-up. Primary myoepithelial cells and myoepithelial cell lines, with and without αvβ6 expression, were used to measure the effect of αvβ6 on growth and invasion of tumor cell lines in vitro and in a xenograft mouse model. Involvement of TGFβ signaling was established using mink lung epithelial cell (MLEC) assay and antibody inhibition, and expression and activation of matrix metalloproteinase (MMP)-9 established by Real Time-PCR and zymography.

RESULTS

Expression of αvβ6 is significantly associated with progression to invasive cancer (P < 0.006) and with recurrence over a median follow-up of 114 months in a series of matched DCIS cases treated with local excision. We show that expression of αvβ6 drives myoepithelial cells to promote tumor cell invasion in vitro and enhances mammary tumor growth in vivo. The tumor-promoting effect of αvβ6-positive myoepithelial cells is dependent on TGFβ-driven upregulation of MMP9 and can be abrogated by inhibiting this pathway.

CONCLUSION

These findings indicate that altered myoepithelial cells in DCIS predict disease progression and recurrence and show that upregulation of αvβ6 on myoepithelial cells generates a tumor promoter function through TGFβ upregulation of MMP-9. These data suggest that expression of αvβ6 may be used to stratify patients with DCIS.

Clinicopathologic features of ductal carcinoma in situ in young women with an emphasis on molecular subtype

Young women with ductal carcinoma in situ treated by breast-conserving therapy have a higher recurrence rate than do older women, and a younger age at diagnosis is associated with worse overall survival after recurrence. This study explores the clinical, pathologic, and immunohistochemical characteristics of ductal carcinoma in situ lesions diagnosed in women 40 years and younger with a focus on molecular subtypes to elucidate features that may contribute to the purported worse outcome for this patient population. Forty-one patients diagnosed with ductal carcinoma in situ at age 40 years and younger were identified over a 10-year period; 31 cases were used to construct tissue microarrays. The microarrays were labeled with antibodies to estrogen receptor, progesterone receptor, HER2, Ki-67, CK5/6, epidermal growth factor receptor, and p53 and subsequently classified as luminal A, luminal B, HER2, basal-like, or unclassifiable triple negative. All patients had high-grade (73.2%) or intermediate-grade (26.8%) ductal carcinoma in situ. The molecular subtype breakdown was 61.3% luminal A, 22.6% luminal B, 13% HER2, and 3.1% unclassifiable triple negative. The mean Ki-67 by subtype was 4.2%, 14%, 9.5%, and 50%, respectively. Mastectomy was performed in 33 patients (80%). Eight patients (20%) underwent excisional biopsy without subsequent mastectomy. In addition to a predominance of high-grade lesions, young patients had a high proportion of luminal B subtype, which may contribute to an increased rate of local recurrence in this population. A larger series is necessary to confirm the impact that the molecular subtypes of ductal carcinoma in situ in younger patients might have on outcome.

Is DCIS breast cancer, and how do I treat it?

Ductal carcinoma in situ (DCIS) is a pre-invasive stage of breast cancer with a heterogeneous clinical behaviour. Since the introduction of mammographic screening programmes, the incidence of DCIS has shown a dramatic increase. Treatment should focus on the prevention of progression to invasive disease. If progression occurs, poorly differentiated DCIS frequently gives rise to grade III invasive breast cancer, whereas well differentiated DCIS more often recurs as grade I invasive disease. However, at present, validated diagnostic test are lacking to predict progression accurately. The majority of women with DCIS are suitable for breast conserving therapy. Obtaining clear surgical margins is the most important goal of a local excision. Radiotherapy is effective in reducing the risk of local recurrence with about 50 % in all subgroups of patients with DCIS. (Breast cancer specific) survival of women with DCIS is excellent, and radiotherapy does not further improve this. Future research should be directed in enabling to select women who have a high risk of--invasive--recurrence, so in which radiotherapy should be standard part of the breast conserving approach, and those women with a more indolent lesion, in which after surgery a watchful waiting approach can be followed.

Progression from ductal carcinoma in situ to invasive breast cancer: revisited

Ductal carcinoma in situ (DCIS) is an intraductal neoplastic proliferation of epithelial cells that is separated from the breast stroma by an intact layer of basement membrane and myoepithelial cells. DCIS is a non-obligate precursor of invasive breast cancer, and up to 40% of these lesions progress to invasive disease if untreated. Currently, it is not possible to predict accurately which DCIS would be more likely to progress to invasive breast cancer as neither the significant drivers of the invasive transition have been identified, nor has the clinical utility of tests predicting the likelihood of progression been demonstrated. Although molecular studies have shown that qualitatively, synchronous DCIS and invasive breast cancers are remarkably similar, there is burgeoning evidence to demonstrate that intra-tumor genetic heterogeneity is observed in a subset of DCIS, and that the process of progression to invasive disease may constitute an 'evolutionary bottleneck', resulting in the selection of subsets of tumor cells with specific genetic and/or epigenetic aberrations. Here we review the clinical challenge posed by DCIS, the contribution of the microenvironment and genetic aberrations to the progression from in situ to invasive breast cancer, the emerging evidence of the impact of intra-tumor genetic heterogeneity on this process, and strategies to combat this heterogeneity.

Accurate assessment of HER2 gene status for invasive component of breast cancer by combination of immunohistochemistry and chromogenic In Situ hybridization

The specimens of ductal carcinoma in situ (DCIS) with early invasion, and specimens collected by core needle biopsy (CNB) tend to contain limited amount of invasive component, so it is imperative to explore a new technique which can assess HER2 gene status accurately for the limited invasive cancer component in these specimens. Dual staining technique of combining immunohistochemistry (IHC) for myoepithelial cells and single or dual probe chromogenic in situ hybridization (CISH) for HER2 gene was performed on routinely processed paraffin sections from 20 cases diagnosed as having DCIS with invasive cancer. Among them, 10 had fluorescence in situ hybridization (FISH)-confirmed amplification of HER2 and 10 had FISH-confirmed non-amplification of HER2. We successfully detected HER2 genetic signals and myoepithelial IHC markers (SMM-HC or CK5/6) simultaneously on a single section in all 20 specimens. Myoepithelial markers and HER2 signals detected by dual staining assay were consistent with those by individual technique performed alone. HER2 gene amplification results determined by dual staining assay were 100% consistent with those of FISH. Dual staining technique which allows simultaneous detection of myoepithelial marker protein and cancerous HER2 gene is feasible, and it has potential to be used in clinical practice for effective determination of HER2 amplification in limited invasive component.

Expression and sub-cellular localization of an epigenetic regulator, co-activator arginine methyltransferase 1 (CARM1), is associated with specific breast cancer subtypes and ethnicity

BACKGROUND

Co-Activator Arginine Methyltransferase 1(CARM1) is an Estrogen Receptor (ER) cofactor that remodels chromatin for gene regulation via methylation of Histone3. We investigated CARM1 levels and localization across breast cancer tumors in a cohort of patients of either European or African ancestry.

METHODS

We analyzed CARM1 levels using tissue microarrays with over 800 histological samples from 549 female cancer patients from the US and Nigeria, Africa. We assessed associations between CARM1 expression localized to the nucleus and cytoplasm for 11 distinct variables, including; ER status, Progesterone Receptor status, molecular subtypes, ethnicity, HER2+ status, other clinical variables and survival.

RESULTS

We found that levels of cytoplasmic CARM1 are distinct among tumor sub-types and increased levels are associated with ER-negative (ER-) status. Higher nuclear CARM1 levels are associated with HER2 receptor status. EGFR expression also correlates with localization of CARM1 into the cytoplasm. This suggests there are distinct functions of CARM1 among molecular tumor types. Our data reveals a basal-like subtype association with CARM1, possibly due to expression of Epidermal Growth Factor Receptor (EGFR). Lastly, increased cytoplasmic CARM1, relative to nuclear levels, appear to be associated with self-identified African ethnicity and this result is being further investigated using quantified genetic ancestry measures.

CONCLUSIONS

Although it is known to be an ER cofactor in breast cancer, CARM1 expression levels are independent of ER. CARM1 has distinct functions among molecular subtypes, as is indicative of its sub-cellular localization and it may function in subtype etiology. These sub-cellular localization patterns, indicate a novel role beyond its ER cofactor function in breast cancer. Differential localization among ethnic groups may be due to ancestry-specific polymorphisms which alter the gene product.

Immunohistochemical profile of high-grade ductal carcinoma in situ of the breast

OBJECTIVE

To determine the frequency of the immunohistochemical profiles of a series of high-grade ductal carcinoma in situ of the breast.

METHODS

One hundred and twenty-one cases of high-grade ductal carcinoma in situ, pure or associated with invasive mammary carcinoma, were identified from 2003 to 2008 and examined with immunohistochemistry for estrogen receptor, human epidermal growth factor receptor 2, cytokeratin 5, and epidermal growth factor receptor. The tumors were placed into five subgroups: luminal A, luminal B, HER2, basal-like, and "not classified".

RESULTS

The frequencies of the immunophenotypes of pure ductal carcinoma in situ were the following: luminal A (24/42 cases; 57.1%), luminal B (05/42 cases; 11.9%), HER2 (07/42 cases; 16.7%), basal-like phenotype (00/42 cases; 0%), and "not classified" (06/42 cases; 14.3%). The immunophenotypes of ductal carcinoma in situ associated with invasive carcinoma were the following: luminal A (46/79 cases; 58.2%), luminal B (10/79 cases; 12.7%), HER2 (06/79 cases; 7.6%), basal-like (06/79 cases; 7.6%), and "not classified" (11/79 cases; 13.9%). There was no significant difference in the immunophenotype frequencies between pure ductal carcinoma in situ and ductal carcinoma in situ associated with invasive carcinoma (p>0.05). High agreement was observed in immunophenotypes between both components (kappa=0.867).

CONCLUSION

The most common immunophenotype of pure ductal carcinoma in situ was luminal A, followed by HER2. The basal-like phenotype was observed only in ductal carcinoma in situ associated with invasive carcinoma, which had a similar phenotype.

Ductal carcinoma in situ associated with triple negative invasive breast cancer: evidence for a precursor-product relationship

AIMS

We evaluated pathological features of the ductal carcinoma in situ component of 241 triple negative invasive breast cancers.

RESULTS

We found that 151 (62.6%) in situ lesions were of high nuclear grade, and 236 (97.9%) were triple negative (oestrogen receptor, progesterone receptor, cerbB2 negative). Immunohistochemistry for cytokeratin (CK)5/6, CK14, CK17, epidermal growth factor receptor (EGFR), CD117, 34βE12, p63 and smooth muscle actin (SMA) revealed positive staining in 5 (2.1%), 60 (24.9%), 69 (28.6%), 37 (15.4%), 69 (28.6%), 137 (56.8%), 3 (1.2%) and 22 (9.1%) in situ ductal components respectively, with fair to substantial agreement of staining results (positive versus negative) between in situ and corresponding invasive elements for CK5/6, CK14, CK17, EGFR, CD117 and 34βE12; but none to fair agreement for p63 and SMA respectively. When the tri-panel of CK14, EGFR and 34βE12 was used to define the basal phenotype, 68% revealed basal-like expression of both in situ and invasive components of the same case.

CONCLUSIONS

Our data support the notion that triple negative ductal carcinoma in situ is the precursor of the corresponding invasive counterpart, and that basal-like expression is maintained in the majority of invasive cancers associated with basal-like in situ disease. Future studies that prospectively evaluate morphological and biological characteristics of invasive cancers that develop from triple negative and basal-like ductal carcinoma in situ lesions will assist in validating these findings.

Ductal carcinoma in situ: what the pathologist needs to know and why

Ductal carcinoma in situ is a proliferation of malignant epithelial cells confined to the ductolobular system of the breast. It is considered a pre-cursor lesion for invasive breast cancer and when identified patients are treated with some combination of surgery, +/− radiation therapy, and +/adjuvant tamoxifen. However, no good biomarkers exist that can predict with accuracy those cases of DCIS destined to progress to invasive disease or once treated those patients that are likely to suffer a recurrence; thus, in the era of screening mammography it seems likely that many patients with DCIS are overtreated. This paper details the parameters that should be included in a pathology report for a case of DClS with some explanations as to their importance for good clinical decision making.

RNA-Seq of human breast ductal carcinoma in situ models reveals aldehyde dehydrogenase isoform 5A1 as a novel potential target

Breast ductal carcinoma in situ (DCIS) is being found in great numbers of women due to the widespread use of mammography. To increase knowledge of DCIS, we determined the expression changes that are common among three DCIS models (MCF10.DCIS, SUM102 and SUM225) compared to the MCF10A model of non-tumorigenic mammary epithelial cells in three dimensional (3D) overlay culture with reconstituted basement membrane (rBM). Extracted mRNA was subjected to 76 cycles of deep sequencing (RNA-Seq) using Illumina Genome Analyzer GAIIx. Analysis of RNA-Seq results showed 295 consistently differentially expressed transcripts in the DCIS models. These differentially expressed genes encode proteins that are associated with a number of signaling pathways such as integrin, fibroblast growth factor and TGFβ signaling, show association with cell-cell signaling, cell-cell adhesion and cell proliferation, and have a notable bias toward localization in the extracellular and plasma membrane compartments. RNA-Seq data was validated by quantitative real-time PCR of selected differentially expressed genes. Aldehyde dehydrogenase 5A1 (ALDH5A1) which is an enzyme that is involved in mitochondrial glutamate metabolism, was over-expressed in all three DCIS models at both the mRNA and protein levels. Disulfiram and valproic acid are known to inhibit ALDH5A1 and are safe for chronic use in humans for other disorders. Both of these drugs significantly inhibited net proliferation of the DCIS 3D rBM overlay models, but had minimal effect on MCF10A 3D rBM overlay models. These results suggest that ALDH5A1 may play an important role in DCIS and potentially serve as a novel molecular therapeutic target.

In search of triple-negative DCIS: tumor-type dependent model of breast cancer progression from DCIS to the invasive cancer

This paper is based on the idea that ductal breast cancer in situ (DCIS) precedes the invasive breast cancer (invBC), although the triple-negative invBCs almost lack their DCIS precursor. Reported incidences of breast tumor types in DCIS and in invasive BCs suggest that probabilities of tumor progression might differ among tumor types, and these differences can have some impact on our patients. Reported data from several papers on incidences of the four breast tumor types-luminal A, luminal B, HER2, and triple negative-are used to compare tumor-type incidences for DCIS and for the invasive BC. The pooled distributions differed (Χ (2) = 97.05, p < 0.0001), suggesting a strong selection pressure that reduces the number of triple-negative DCIS lesions at the time of breast tumor diagnosis. Reported shares of DCIS in all newly diagnosed breast cancers range in large screening trials from 9 to 26 %, so in making a population model, three values are arbitrarily chosen: one DCIS out of ten breast cancers (the 10 % share), one DCIS out of seven breast cancers (one seventh or the 14.3 % share), and one out of five (the 20 % share). By using these shares and the pooled data of tumor-type incidences, values are calculated that would be expected from a hypothetical population in which types of DCIS and invasive BC are distributed accordingly to the reported incidences. The model predicts that the shares of breast cancer tumor types in the modeled population (DCIS plus invasive BCs) are 39 % for luminal A, 20 % for luminal B, 11 % for HER2 positive, and 30 % for the triple-negative cancers. Some 59 % of all breast tumors are expected to be hormone receptor positive, and HER2 to be overexpressed in 31 %. Simulated probabilities of tumor progression were used to calculate the number of tumor progression t(1/2) that has passed before the time of diagnosis. Calculated relative t(1/2) durations in the modeled population suggest that the triple-negative DCIS cases were fastest in tumor progression, three times faster than the HER2-positive tumors and near twice as fast as luminal A. Luminal A is the model slower than luminal B DCIS, suggesting that although their progression depends on estrogen exposure, HER2 overexpression in luminal B tumors adds some speed in tumor progression. The model results suggest that quick tumor progression might be the main feature of the triple-negative breast tumors, leading to seldom triple-negative DCIS at the time of breast cancer diagnosis. Applying approach of the presented model to the real data from a well-defined population seems warranted.

Pathological controversies in breast cancer: classification of ductal carcinoma in situ, sentinel lymph nodes and low volume metastatic disease and reporting of neoadjuvant chemotherapy specimens

The pathological classification of breast cancer is constantly being updated to reflect the advances in our clinical and biological understanding of the disease. This overview examines new insights into the classification and molecular biology of ductal carcinoma in situ, the pathological handling of sentinel lymph node biopsies and the identification of low volume disease (micrometastases and isolated tumour cells) and the handling and reporting of specimens after neoadjuvant therapy. The molecular subtypes of invasive breast cancer are also represented in ductal carcinoma in situ. It is hoped that alongside traditional histological features, such as cytological grade and the presence of necrosis, this will lead to better classification systems with improved prediction of clinical behaviour, in particular the risk of progression to invasive cancer, and enable more targeted management. Sentinel lymph node biopsy is now the standard of care for early stage breast cancer in clinically node-negative patients. However, the handling and reporting of these specimens remains controversial, largely related to the uncertainties regarding the clinical significance of micrometastases and isolated tumour cells. The increasing use of neoadjuvant therapies has introduced challenges for the pathologist in the handling and interpretation of these specimens. Grading the tumour response, particularly the identification of a complete pathological response, is prognostically important. However, there is still marked variability in reporting these specimens in routine practice, and consensus guidelines for the histopathology reporting of breast cancers after neoadjuvant chemotherapy based on robust, validated evidence are presently lacking.

Molecular heterogeneity in malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1

Neurofibromatosis type-1 (NF1), resulting from NF1 gene loss of function, is characterized by an increased risk of developing benign and malignant peripheral nerve sheath tumors (MPNSTs). Whereas the cellular heterogeneity of NF1-associated tumors has been well studied, the molecular heterogeneity of MPNSTs is still poorly understood. Mutational heterogeneity within these malignant tumors greatly complicates the study of the underlying mechanisms of tumorigenesis. We have explored this molecular heterogeneity by performing loss of heterozygosity (LOH) analysis of the NF1, TP53, RB1, PTEN, and CDKN2A genes on sections of 10 MPNSTs derived from 10 unrelated NF1 patients. LOH data for the TP53 gene was found to correlate with the results of p53 immunohistochemical analysis in the same tumor sections. Further, approximately 70% of MPNSTs were found to display intra-tumoral molecular heterogeneity as evidenced by differences in the level of LOH between different sections of the same tumor samples. This study constitutes the first systematic analysis of molecular heterogeneity within MPNSTs derived from NF1 patients. Appreciation of the existence of molecular heterogeneity in NF1-associated tumors is important not only for optimizing somatic mutation detection, but also for understanding the mechanisms of NF1 tumorigenesis, a prerequisite for the development of specifically targeted cancer therapeutics.

Ductal carcinoma in situ: recent advances and future prospects

Introduction. This article reviews current management strategies for DCIS in the context of recent randomised trials, including the role of sentinel lymph node biopsy (SLNB), adjuvant radiotherapy (RT) and endocrine treatment. Methods. Literature review facilitated by Medline, PubMed, Embase and Cochrane databases. Results. DCIS should be managed in the context of a multidisciplinary team. Local control depends upon clear surgical margins (at least 2 mm is generally acceptable). SLNB is not routine, but can be considered in patients undergoing mastectomy (Mx) with risk factors for occult invasion. RT following BCS significantly reduces local recurrence (LR), particularly in those at high-risk. There remains a lack of level-1 evidence supporting omission of adjuvant RT in selected low-risk cases. Large, multi-centric or recurrent lesions should be treated by Mx and immediate reconstruction should be discussed. Adjuvant hormonal treatment may reduce the risk of LR in selected cases with hormone sensitive disease. Conclusion. Further research is required to determine the role of new RT regimes and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of tumour biology in DCIS to rationalise treatment. Reliable identification of low-risk lesions could allow treatment to be less radical.

Intraductal proliferative lesions of the breast-terminology and biology matter: premalignant lesions or preinvasive cancer?

Morphological criteria for the diagnosis of intraductal proliferative lesions of the breast have been an object of research and much controversy, and its terminology is rather confusing. Knowledge of the molecular aspects of this disease probably necessitates further research to clarify if these entities can be identified as breast cancer precursors or as a malignant preinvasive disease. These issues are of great interest not only for their biological implications, but also to the clinician who must understand the disease and direct therapies. Molecular studies have shown that epitheliosis (usual ductal hyperplasia) is not monoclonal, while malignant lesions (atypical ductal hyperplasia, flat epithelial atypia, low-grade and high-grade intraductal carcinoma) constantly show these characteristics. These malignant lesions, classified with a DIN grading system (ductal intraepithelial neoplasia), are not obligate precursors of invasive ductal carcinoma and do not represent different evolving grades in a linear model of cancerogenesis. Breast cancerogenesis probably has different pathways with different morphologic precursors.

ASPN and GJB2 Are Implicated in the Mechanisms of Invasion of Ductal Breast Carcinomas

The mechanism of progression from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) remains largely unknown. We compared gene expression in tumors with simultaneous DCIS and IDC to decipher how diverse proteins participate in the local invasive process.

Twenty frozen tumor specimens with concurrent, but separated, DCIS and IDC were microdissected and evaluated. Total RNA was extracted and microarray analysis was performed using Affymetrix GeneChip® Human Gene 1.0 ST Arrays. Microarray data were validated by quantitative real time reverse transcription-PCR (qRT-PCR) and immunohistochemistry. Controls included seven pure in situ carcinomas, eight fragments from normal breast tissue, and a series of mouse breast carcinomas (MMTV-PyMT).

Fifty-six genes were differentially expressed between DCIS and IDC samples. The genes upregulated in IDC samples, and probably associated with invasion, were related to the epithelial-mesenchymal transition (ASPN, THBS2, FN1, SPARC, and COL11A1), cellular adhesion (GJB2), cell motility and progression (PLAUR, PLAU, BGN, ADAMTS16, and ENPP2), extracellular matrix degradation (MMP11, MMP13, and MMP14), and growth/proliferation (ST6GAL2). qRT-PCR confirmed the expression patterns of ASPN, GJB2, ENPP2, ST6GAL2, and TMBS10. Expression of the ASPN and GJB2 gene products was detected by immunohistochemistry in invasive carcinoma foci. The association of GJB2 protein expression with invasion was confirmed by qRT-PCR in mouse tumors (P < 0.05).

Conclusions: The upregulation of ASPN and GJB2 may play important roles in local invasion of breast ductal carcinomas.