Application of immunohistochemistry to breast lesions

Prediction of Receptor Status in Radiomics: Recent Advances in Breast Cancer Research

Breast cancer is a multifactorial heterogeneous disease and the leading cause of cancer-related deaths in women; its diagnosis and treatment require clinical sensitivity and a comprehensive disciplinary research approach. The expression of different receptors on tumor cells not only provides the basis for molecular typing of breast cancer but also has a decisive role in the diagnosis, treatment, and prognosis of breast cancer. To date, immunohistochemistry (IHC), which uses invasive histological sampling, has been extensively used in clinical practice to analyze the status of receptors and to make an accurate diagnosis of breast cancer. As an invasive assay, IHC can provide important biological information on tumors at a single point in time, but cannot predict future changes (due to treatment or tumor mutations) without additional invasive procedures. These issues highlight the need to develop a non-invasive method for predicting receptor status. The emerging field of radiomics may offer a non-invasive approach to identification of receptor status without requiring biopsy. In this paper, we present a review of the latest research results in radiomics for predicting the status of breast cancer receptors, with potential important clinical applications.

Nontoxic Fluorescent Nanoprobes for Multiplexed Detection and 3D Imaging of Tumor Markers in Breast Cancer

Multiplexed fluorescent immunohistochemical analysis of breast cancer (BC) markers and high-resolution 3D immunofluorescence imaging of the tumor and its microenvironment not only facilitate making the disease prognosis and selecting effective anticancer therapy (including photodynamic therapy), but also provides information on signaling and metabolic mechanisms of carcinogenesis and helps in the search for new therapeutic targets and drugs. The characteristics of imaging nanoprobe efficiency, such as sensitivity, target affinity, depth of tissue penetration, and photostability, are determined by the properties of their components, fluorophores and capture molecules, and by the method of their conjugation. Regarding individual nanoprobe components, fluorescent nanocrystals (NCs) are widely used for optical imaging in vitro and in vivo, and single-domain antibodies (sdAbs) are well established as highly specific capture molecules in diagnostic and therapeutic applications. Moreover, the technologies of obtaining functionally active sdAb–NC conjugates with the highest possible avidity, with all sdAb molecules bound to the NC in a strictly oriented manner, provide 3D-imaging nanoprobes with strong comparative advantages. This review is aimed at highlighting the importance of an integrated approach to BC diagnosis, including the detection of biomarkers of the tumor and its microenvironment, as well as the need for their quantitative profiling and imaging of their mutual location, using advanced approaches to 3D detection in thick tissue sections. The existing approaches to 3D imaging of tumors and their microenvironment using fluorescent NCs are described, and the main comparative advantages and disadvantages of nontoxic fluorescent sdAb–NC conjugates as nanoprobes for multiplexed detection and 3D imaging of BC markers are discussed.

Carcinoma of Unknown Primary Origin: Application of Immunohistochemistry With Emphasis to Different Cytokeratin 7 and 20 Staining Patterns

BACKGROUND

Although the primary origin of some carcinomas may be obscure to clinicians, its identification is crucial as it affects prognosis and treatment (especially novel targeted therapies). Immunohistochemistry (IHC) may be helpful in identifying the primary origin of carcinomas. This retrospective survey aimed to evaluate the frequency and accuracy of each IHC marker used to determine the origin of carcinomas.

METHODS

The review of pathology department archives revealed 307 cases of cancer of unknown primary origin (CUP) between 2015 and 2020, which were accessible in the department archives. Demographic information, site of biopsy, clinical and pathologic diagnoses, and IHC results of the patients were collected.

RESULTS

The patients included 157 (51.15%) men and 150 (48.85%) women. The age of the patients ranged from 14 to 92 years, including 106 (34.5%) expired cases. In 27% of cases, the primary origin of carcinoma remained unknown. The agreement between pathologic and clinical diagnoses was 59%. The most common pattern of cytokeratin (CK) expression in CUP was CK7+/CK20- (55.3%), followed by CK7-/CK20- (19%), CK7+/CK20+ (15%), and CK7-/CK20+ (10.7%), respectively.

CONCLUSION

The IHC analysis may improve the diagnosis of CUPs. However, the origin of some cases remains unknown despite an IHC analysis, thereby necessitating the use of more diagnostic procedures or gene expression studies for reaching a definitive diagnosis.

Lack of Clinical Value for Immunohistochemistry for Sentinel Lymph Node Assessment in Invasive Lobular Carcinoma

BACKGROUND

The distinct histologic appearance of invasive lobular carcinoma (ILC) may pose diagnostic challenges for sentinel lymph node (SLN) analysis. We evaluated the impact of cytokeratin immunohistochemistry (IHC) on SLN assessment in ILC and its contribution to pathologic nodal upstaging.

METHODS

We identified ILC patients treated with SLN surgery at our institution between September 2008 and August 2021. IHC for SLN assessment was employed at the discretion of the pathologist. Differences between groups evaluated with and without IHC were compared using Chi-square tests.

RESULTS

Overall, 608 cases of ILC were identified in patients who underwent SLN surgery. IHC was used in 301 cases (49.5%) and was not associated with cT category, pT category, or tumor grade. Use of IHC increased detection of SLN+ disease when isolated tumor cells (ITCs) were included in the analysis (35.9% with IHC vs. 21.2% without IHC; p < 0.001). There was no effect on nodal upstaging to micrometastatic disease (pN1mi) or greater (21.9% with IHC vs. 21.2% without IHC; p = 0.82). IHC did not increase the number of positive SLNs detected (median 1 with and without IHC) nor did it increase axillary lymph node dissection (ALND) rates (11.6% with IHC vs. 15.3% without IHC; p = 0.18).

CONCLUSION

IHC improved detection of pN0(i+) disease among ILC patients undergoing SLN surgery. IHC did not increase upstaging to pN1mi or higher categories of nodal disease, detection of a greater number of positive SLNs, or ALND rates. Our data suggest routine use of IHC for SLN assessment in ILC patients does not add clinical utility.

Tumor microenvironment-related multigene prognostic prediction model for breast cancer

BACKGROUND

Breast cancer is an invasive disease with complex molecular mechanisms. Prognosis-related biomarkers are still urgently needed to predict outcomes of breast cancer patients.

METHODS

Original data were download from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). The analyses were performed using perl-5.32 and R-x64-4.1.1.

RESULTS

In this study, 1086 differentially expressed genes (DEGs) were identified in the TCGA cohort; 523 shared DEGs were identified in the TCGA and GSE10886 cohorts. Eight subtypes were estimated using non-negative matrix factorization clustering with significant differences seen in overall survival (OS) and progression-free survival (PFS) (P < 0.01). Univariate Cox analysis and least absolute shrinkage and selection operator (LASSO) regression analysis were performed to develop a related risk score related to the 17 DEGs; this score separated breast cancer into low- and high-risk groups with significant differences in survival (P < 0.01) and showed powerful effectiveness (TCGA all group: 1-year area under the curve [AUC] = 0.729, 3-year AUC = 0.778, 5-year AUC = 0.781). A nomogram prediction model was constructed using non-negative matrix factorization clustering, the risk score, and clinical characteristics. Our model was confirmed to be related with tumor microenvironment. Furthermore, DEGs in high-risk breast cancer were enriched in histidine metabolism (normalized enrichment score [NES] = 1.49, P < 0.05), protein export (NES = 1.58, P < 0.05), and steroid hormone biosynthesis signaling pathways (NES = 1.56, P < 0.05).

CONCLUSIONS

We established a comprehensive model that can predict prognosis and guide treatment.

Analysis of breast cancer subtypes and their correlations with receptors and ultrasound

The study aim was to evaluate the ultrasound (US) signs of the mammary lesions classified in the Breast Imaging-Reporting and Data System (BI-RADS) score category 3, 4, and 5, corresponding to US BI-RADS. It also followed the correlation between US changes of lesions suggestive for malignancy with the histopathological results and evaluated the proper management of those lesions. There were correlations of breast cancer (BC) subtypes with the receptors [estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2)], and Ki67 index, and the signs of conventional ultrasonography and US elastography. We selected 108 female patients examined with US, mammography and fine-needle biopsy who presented suspicions for malignancy lesions. Following the immunohistochemical analysis, they were classified in one of the BC subtypes. According to chi-squared analysis of molecular cancer subtypes correlation to receptors and Ki67 index, we found significant associations between both luminal A and luminal B HER2-negative subtypes and hormone receptors (ER, PR). These have an inverse relationship with Ki67 index elevated values; luminal B HER2-positive subtype has a direct association with HER2 presence; HER2-enriched subtype was statistically significant associated to HER2 presence and elevated Ki67 index values but had an inverse relationship to hormone receptors (ER, PR); triple-negative subtype was strongly associated to Ki67 index values and inversely correlated to ER and PR. We found luminal A subtype as being the most common and luminal B HER2-positive subtype as having the fewer cases.

Single-cell evaluation reveals shifts in the tumor-immune niches that shape and maintain aggressive lesions in the breast

There is an unmet clinical need for stratification of breast lesions as indolent or aggressive to tailor treatment. Here, single-cell transcriptomics and multiparametric imaging applied to a mouse model of breast cancer reveals that the aggressive tumor niche is characterized by an expanded basal-like population, specialization of tumor subpopulations, and mixed-lineage tumor cells potentially serving as a transition state between luminal and basal phenotypes. Despite vast tumor cell-intrinsic differences, aggressive and indolent tumor cells are functionally indistinguishable once isolated from their local niche, suggesting a role for non-tumor collaborators in determining aggressiveness. Aggressive lesions harbor fewer total but more suppressed-like T cells, and elevated tumor-promoting neutrophils and IL-17 signaling, disruption of which increase tumor latency and reduce the number of aggressive lesions. Our study provides insight into tumor-immune features distinguishing indolent from aggressive lesions, identifies heterogeneous populations comprising these lesions, and supports a role for IL-17 signaling in aggressive progression.

Triple-negative breast cancer: A run-through of features, classification and current therapies

Breast cancer is the most prevalent cancer in women worldwide. Triple-negative breast cancer (TNBC) is characterized by the lack of expression of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. It is the most aggressive subtype of breast cancer and accounts for 12-20% of all breast cancer cases. TNBC is associated with younger age of onset, greater metastatic potential, higher incidence of relapse, and lower overall survival rates. Based on molecular phenotype, TNBC has been classified into six subtypes (BL1, BL2, M, MES, LAR, and IM). TNBC treatment is challenging due to its heterogeneity, highly invasive nature, and relatively poor therapeutics response. Chemotherapy and radiotherapy are conventional strategies for the treatment of TNBC. Recent research in TNBC and mechanistic understanding of disease pathogenesis using cutting-edge technologies has led to the unfolding of new lines of therapies that have been incorporated into clinical practice. Poly (ADP-ribose) polymerase and immune checkpoint inhibitors have made their way to the current TNBC treatment paradigm. This review focuses on the classification, features, and treatment progress in TNBC. Histological subtypes connected to recurrence, molecular classification of TNBC, targeted therapy for early and advanced TNBC, and advances in non-coding RNA in therapy are the key highlights in this review.

Correlation of expression of hormone and HER2 receptors with various clinico-pathological prognostic parameters and with each other in malignant breast lesion

BACKGROUND

Estrogen receptors (ER), progesterone receptors (PR) and the human epidermal growth factor receptor-2 (HER2) are basic breast cancer molecular markers that are also best recognized prognostic factors and predictors of type of targeted therapy to be given. The objectives are to study the correlation of expression of hormone and HER2receptors with various clinico-pathological prognostic parameters like patient's age at diagnosis, menopausal status, tumor size, histological grade and lymph node status of tumor and with each other in malignant breast lesion.

METHODS

For this study histopathology (HP) and immunohistochemistry (IHC) slides of excised specimens of 330 female patients with a palpable breast lump deposited to the pathology department of a hospital as a part of routine diagnostic procedure, were evaluated under the guidance of trained doctors who have minimum 5 years of experience in oncopathology. The author has no direct involvement with patients, informed consent was not necessary and data were collected after getting permission from concerned authority.

RESULTS

This study finds significant relationship between hormone receptors and all clinico-pathological prognostic parameters taken for comparison except age at diagnosis. HER2 status has significant relationship with all clinico-pathological prognostic parameters; hormone and HER2 status suggests an inverse relationship.

CONCLUSIONS

Mien of hormone receptors expression in breast cancer is related with better prognostic factors such as older age, postmenopausal status, smaller tumor size, low histological grade and negative lymph node status, however the opposite is correct for HER2. Hormone receptors and HER2 have an inversely proportionate relationship with each other.

Advances in Diagnostic Procedures and Their Applications in the Era of Cancer Immunotherapy

Diagnostic procedures play critical roles in cancer immunotherapy. In this chapter, we briefly discuss three major diagnostic procedures widely used in immunotherapy: immunohistochemistry, next-generation sequencing, and flow cytometry. We also describe the uses of other diagnostic procedures and preclinical animal models in cancer immunotherapy translational research.

Is Danggui Safe to be Taken by Breast Cancer Patients?-A Skepticism Finally Answered by Comprehensive Preclinical Evidence

Angelica sinensis (AS, Danggui) has long been regarded to stimulate breast cancer growth; hence, the use of AS in breast cancer patients remains a major concern for both patients and practitioners. Since safety studies of herbs would be unethical to carry out in patients, the present study aimed to investigate the potential unsafe effects of AS in a systematic pre-clinical approach. Human breast cancer cells, breast orthotopic tumor-bearing mouse models, as well as primary breast cancer cells from patients’ tumors were used to evaluate the effect of AS hot water extract on the progression of breast tumors and/or growth of breast cancer cells. We showed that AS is not that stimulatory in breast cancer both in vitro and in vivo, though AS should still be used with caution in estrogen receptor-positive breast cancer patients. This novel approach of applying breast cancer cell lines, xenograft, and syngeneic tumors models, as well as primary breast cancer cells from patients’ tumors in Chinese medicines safety evaluation was proven feasible. Our finding is important information for patients, Chinese medicine practitioners, and clinicians on the safety use of AS in breast cancer, which will affect future clinical practice.

Clinicopathological study of a dimorphic variant of breast carcinoma

BACKGROUND

Dimorphic cells have abundant clear cytoplasm similar to myoepithelial cells, and the nuclei are identical to those in adjacent malignant columnar epithelial cells. A dimorphic variant of a breast carcinoma involves a neoplastic proliferation of epithelial cells including dimorphic cells.

METHODS

The subjects were patients with primary breast carcinoma, who underwent surgical resection at the Hospital of Dokkyo Medical University between 2000 and 2016, and were reviewed and diagnosed with a dimorphic variant of breast carcinoma.

RESULTS

Dimorphic ICs typically showed a low-grade tumor and Hormonal receptor (HR) (estrogen and/or progesterone)+/HER2- subtype. Age, mean tumor size, status of nodal metastasis, stage and disease-free survival and overall survival did not differ between dimorphic and non-dimorphic ICs. The dimorphic cells were negative for p63 and cytokeratin 5/6 and 14 in most cases. In contrast, dimorphic cells were positive for HR, androgen receptor, and showed marked membrane-associated staining for E-cadherin and cytoplasmic staining for gross cystic disease fluid protein 15.

CONCLUSIONS

The morphological features of dimorphic cells may be confused with cells of other origins if the features of the dimorphic cells are not recognized. However, the typical morphological architecture of this carcinoma and expression of immunohistochemical markers support the diagnosis.

Multicolor immunofluorescence reveals that p63- and/or K5-positive progenitor cells contribute to normal breast epithelium and usual ductal hyperplasia but not to low-grade intraepithelial neoplasia of the breast

We contend that knowledge about the cellular composition of normal breast epithelium is a prerequisite for understanding proliferative breast disease. Against this background, we used multicolor immunofluorescence to study normal breast epithelium and two types of intraepithelial proliferative breast lesion for expression of the p63, basal keratin K5, glandular keratin K8/18, SMA, ER-alpha, and Ki67. We studied eight normal breast epithelium samples, 12 cases of usual ductal hyperplasia, and 33 cases of low-grade intraepithelial neoplasia (9 flat epithelial atypia, 14 low-grade ductal carcinoma in situ and 10 cases of lobular neoplasia). Usual ductal hyperplasia showed striking similarity to normal luminal breast epithelium including p63+ and/or K5+ luminal progenitor cells and the full spectrum of luminal progeny cells. In normal breast epithelium and usual ductal hyperplasia, expression of ER-alpha was associated with lack of expression of the proliferation antigen Ki67. In contrast, we found in both types of low-grade intraepithelial neoplasia robust expression of keratin K8/18 and a positive association between ER-alpha and Ki67 expression. However, these lesions were consistently negative for p63 and/or K5. Our observational study supports the view that usual ductal hyperplasia and low-grade intraepithelial neoplasia are different entities rather than part of a spectrum of the same disease. We propose a new operational model of cell differentiation that may serve to better understand correlations between normal breast epithelium and proliferative breast diseases. From our data we conclude that p63+ and/or K5+ progenitor cells contribute to maintenance of normal epithelium and usual ductal hyperplasia, but not to low-grade intraepithelial neoplasia of the breast.

Diversity of Breast Carcinoma: Histological Subtypes and Clinical Relevance

Mammary carcinoma is the most common malignant tumor in women, and it is the leading cause of mortality, with an incidence of >1,000,000 cases occurring worldwide annually. It is one of the most common human neoplasms, accounting for approximately one-quarter of all cancers in females worldwide and 27% of cancers in developed countries with a Western lifestyle. They exhibit a wide scope of morphological features, different immunohistochemical profiles, and unique histopathological subtypes that have specific clinical course and outcome. Breast cancers can be classified into distinct subgroups based on similarities in the gene expression profiles and molecular classification.

UK national survey of management of breast lobular carcinoma in situ

INTRODUCTION

There is no national standard treatment for patients with breast lobular carcinoma in situ (LCIS). Association of Breast Surgery guidelines for the management of breast cancer suggest that lesions containing LCIS should be excised for definitive diagnosis and recommend close surveillance after excision biopsy. The aim of this study was to form a picture of the current management of LCIS by UK breast surgeons.

METHODS

A questionnaire about the management of LCIS was sent to 490 UK breast surgeons.

RESULTS

Of 490 questionnaires sent out, 173 (35%) were returned. When LCIS is present in a core biopsy, 61% of breast surgeons perform surgical excision, 22% would not excise but would continue follow-up and the remainder perform neither or set no clear management plan. Over half (54%) follow patients up with five years of annual mammography. If classic LCIS were found at the margins of wide local excision, 92% would not re-excise. Conversely, if pleomorphic LCIS were found, 71% would achieve clear margins. Respondents were split evenly regarding management of classic LCIS with a family history as 54% would not alter management whereas 43% would treat the disease more aggressively.

CONCLUSIONS

Our survey has shown that in cases where LCIS is found at core biopsy, most surgeons follow Association of Breast Surgery guidance, obtaining further histological samples to exclude pleomorphic LCIS, ductal carcinoma in situ or invasive cancer, whereas others opt for annual surveillance and some discharge the patient. This study highlighted the huge variability in LCIS management, and the need for randomised controlled trials and input into national audits such as the Sloane Project to establish evidence-based national standard guidelines.

Basal cytokeratin phenotypes of myoepithelial cells indicates the origin of ductal carcinomas in situ of the breast

Terminal duct lobular unit (TDLU) is widely accepted as the origin of ductal carcinoma in situ of breast. The differentiation states of myoepithelial cells of breast ductal system hint the development of breast hyperplastic lesions. Basal cytokeratin (CK) phenotypes indicate the differentiation of myoepithelial cells. Using antibodies of CK5/6, CK14, and CK17, this study reports the basal CK phenotypes of myoepithelial cells in 20 foci of normal breast, 20 usual ductal hyperplasias, 36 ductal carcinomas in situ (DCIS), and 28 sclerosing adenosis (SA). The results showed that the positive staining of basal CKs of myoepithelial cells in normal ducts were significantly higher than those in normal lobules. The basal CK expression of myoepithelial cells of DCIS and usual ductal hyperplasia was similar to that of normal duct, whereas that of SA was similar to that of normal lobule. We propose a modified model of TDLU origin of intraductal carcinoma that most of DCIS originate from terminal ducts of TDLU, whereas most SA originate from lobules.

Breast carcinoma metastasis to the lacrimal gland: Two case reports

A 77-year-old female, with proptosis, reduced eye motility and diplopia which had developed over two to three months and a 69-year-old female with proptosis, oedema of the eyelid, reduced motility and ptosis, which had developed over three weeks, are presented in the present study. Computed tomography scans revealed irregular lacrimal gland tumours in the two patients. The two patients had history of breast cancer. The first breast cancer metastasis in the lacrimal gland demonstrated a cribriform growth pattern containing ductal elements. The epithelial tumour cells stained positive for cytokeratin (1-8, 10, 14-16, 18 and 19), oestrogen receptor, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA) and gross cystic disease fluid protein 15 (GCDFP-15). The second metastatic tumour was positive for EMA and estrogen receptor, but variably positive for CEA and GCDFP-15. The metastasis in the lacrimal gland was a pleomorphic tumour. The tumour cells were positive for EMA and variably positive for oestrogen and CEA. Metastases to the lacrimal gland are extremely rare, and metastases to the lacrimal gland should be considered in the diagnoses of lacrimal gland tumours. The present study aimed to describe two such cases and draw attention to breast carcinomas as a differential diagnosis and the most frequent cause of lacrimal gland metastasis.

Application of immunohistochemistry in breast pathology: a review and update

CONTEXT

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

OBJECTIVE

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

DATA SOURCES

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

CONCLUSIONS

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

The Application of Immunohistochemical Biomarkers in Urologic Surgical Pathology

Context

Tumors of the genitourinary tract can be diagnostically challenging, particularly in core biopsies and cystoscopic biopsies with limited material. Immunohistochemistry is a valuable tool to use when morphology alone is insufficient for diagnosis.

Objectives

To review tumors and benign lesions of the kidney, urinary bladder, prostate gland, testis, and paratesticular structures with an emphasis on difficult differential diagnoses, as well as staining patterns in normal tissue. Recommended immunohistochemical stain panels are discussed that can assist in the diagnostic workup.

Data Sources

Review of current literature.

Conclusions

Immunohistochemistry is a valuable tool, assisting in the diagnosis of problematic tumors and benign lesions of the genitourinary tract.

PTEN/PIK3CA genes are frequently mutated in spontaneous and medroxyprogesterone acetate-accelerated 7,12-dimethylbenz(a)anthracene-induced mammary tumours of tree shrews

Tree shrew has increasingly become an attractive experimental animal model for human diseases, particularly for breast cancer due to spontaneous breast tumours and their close relationship to primates and by extension to humans. However, neither normal mammary glands nor breast tumours have been well characterised in the Chinese tree shrew (Tupaia belangeri chinensis). In this study, normal mammary glands from four different developmental stages and 18 spontaneous breast tumours were analysed. Haematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) showed that normal mammary gland morphology and structures of tree shrews were quite similar to those found in humans. Spontaneous breast tumours of tree shrews were identified as being intraductal papilloma, papillary carcinoma, and invasive ductal carcinoma with or without lung metastasis. To further analyse breast cancer tumours among tree shrews, 40 3-4 month-old female tree shrews were orally administrated 20 mg 7,12-dimethylbenz(a)anthracene (DMBA) or peanut oil thrice, and then, 15 of these DMBA administrated tree shrews were implanted with medroxyprogesterone acetate (MPA) pellets. DMBA was shown to induce breast tumours (12%) while the addition of MPA increased the tumour incidence (50%). Of these, three induced breast tumours were intraductal papillary carcinomas and one was invasive ductal carcinoma (IDC). The PTEN/PIK3CA (phosphatase and tensin homologue/phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha), but not TP53 and GATA3, genes are frequently mutated in breast tumours, and the PTEN/PIK3CA gene mutation status correlated with the expression of pAKT in tree shrew breast tumours. These results suggest that tree shrews may be a promising animal model for a subset of human breast cancers with PTEN/PIK3CA gene mutations.

The clinical use of a P63/cytokeratin7/18/cytokeratin5/14 antibody cocktail in diagnostic breast pathology

An antibody cocktail directed against p63, cytokeratin (CK)5/14, and CK7/18 is reported to be useful in distinguishing noninvasive from invasive breast lesions and for the characterization of intraductal epithelial proliferations. However, limited studies evaluate its use in clinical practice. A retrospective review of breast material at a university medical center identified cases that were immunostained with the above antibody cocktail. Additional p63 immunostaining alone was performed to further determine the utility of the antibody cocktail in the evaluation of invasion. Of 50 breast cases identified, the antibody cocktail was used to confirm or exclude invasion in 44 (88%). Twenty-two (50%) of these had easily identifiable p63/CK5/14-positive myoepithelial cells, whereas the remainder lacked such staining, confirming the diagnosis of invasive carcinoma. In 27 cases with available diagnostic material for additional p63 immunostaining, the cocktail better highlighted myoepithelial cells by staining nuclei and cytoplasm. Easier identification of invasion was also facilitated by CK7/18 expression in invasive foci, especially those composed of single cells. Ten cases were immunostained to help determine the nature of an intraductal proliferation. The cocktail demonstrated a mosaic staining pattern of both CK7/18- and CK5/14-positive epithelial cells in 3 (30%) cases consistent with usual hyperplasia; homogenous CK7/18 expression in the remaining cases supported the diagnosis of atypical ductal hyperplasia or carcinoma in situ. In summary, the p63/CK7/18/CK5/14 cocktail stain appears to be a useful tool in diagnostic breast pathology, in the evaluation of possible invasion, particularly in the setting of minute foci of invasion as well as in epithelial proliferations.

Significance of immunohistochemistry in breast cancer

The biological characteristics of the tumour are used to estimate prognosis and select appropriate systemic therapy for patients with (breast) cancer. The advent of molecular technology has incorporated new biomarkers along with immunohistochemical and serum biomarkers. Immunohistochemical markers are often used to guide treatment decisions, to classify breast cancer into subtypes that are biologically distinct and behave differently, and both as prognostic and predictive factors. Steroid hormone receptors, markers of tumour proliferation, and factors involved in angiogenesis and apoptosis are of scientific interest. In this review we will provide information on the immunohistochemical markers used in the management of breast cancer patients using available data from the literature. We consider the utility of established immunohistochemical markers, and discuss the challenges involved in integrating novel molecular markers into clinical practice.

Morphometric and histological study of breast lesions with special reference to proliferative activity and invasiveness

Breast carcinoma is the most common cause of carcinoma death in women. Sometimes, difficulty arises to differentiate between premalignant lesions and carcinoma by routine histopathology. Our study was done to establish the role of morphometry and immunohistochemistry to solve this problem. In this study, total 60 cases of different breast lesions were included and 10 controls were also included to compare the results with the normal findings. They were studied by hematoxylin and eosin-stained sections for morphometry and routine histological study; as well as by proliferative markers such as proliferating cell nuclear antigen and p53. Invasiveness was studied using immunohistochemical staining with 34 βE12 monoclonal antibody. Statistically significant differences were found in morphometric parameters and in expression of proliferative markers between most of them. Morphometry and immunohistochemistry help in the proper diagnosis of different breast lesions that lie in the gray zone on routine histopathology.

K5/K14-positive cells contribute to salivary gland-like breast tumors with myoepithelial differentiation

Salivary gland-like tumors of the breast show a great variety of architectural patterns and cellular differentiations such as glandular, myoepithelial, squamous, and even mesenchymal phenotypes. However, currently little is known about the evolution and cellular differentiation of these tumors. For that reason, we performed an in situ triple immunofluorescence lineage/differentiation tracing (isTILT) and qRT-PCR study of basal (K5/K14), glandular (K7/K8/18), and epidermal-specific squamous (K10) keratins, p63, and smooth muscle actin (SMA; myoepithelial marker) with the aim to construct and trace different cell lineages and define their cellular hierarchy in tumors with myoepithelial differentiation. isTILT analysis of a series of 28 breast, salivary, and lacrimal gland tumors, including pleomorphic adenomas (n=8), epithelial-myoepithelial tumors (n=9), and adenoid cystic carcinomas (n=11) revealed that all tumor types contained K5/K14-positive progenitor cells in varying frequencies from a few percent up to 15%. These K5/K14-positive tumor cells were found to differentiate to glandular- (K8/18-positive) and myoepithelial-lineage (SMA-positive)-specific cells and were also shown to generate various heterologeous cell differentiations such as squamous and mesenchymal progenies. p63 was co-expressed with K5/K14 in basal-like progenitor cells, myoepithelial, and squamous cells but not in glandular cells. Our results show that the corresponding counterpart tumors of breast and salivary/lacrimal glands have identical cellular compositions. Taken together, our isTILT and RNA-expression data indicate that look-alike tumors of the breast represent a special subgroup of basal-type tumors with benign or usually low malignant potential.

Unexpected diagnosis of both adenocarcinoma of the colon and metastatic lobular carcinoma of the breast in the gastrointestinal tract

Breast cancer rarely metastasises to the gastrointestinal tract. Lobular carcinoma more commonly metastasises to the uterus and appendages, peritoneum, and gastrointestinal tract than other types of breast cancer, while ductal carcinoma has a propensity to metastasise to the lungs, liver, and brain. We describe the case of a patient with no known history of breast cancer, whose primary presentation of lobular breast cancer was with malignant small intestinal and colonic strictures, with coexisting previously undiagnosed adenocarcinoma of the colon.

Ductal carcinoma in situ: morphology-based knowledge and molecular advances

Ductal carcinoma in situ (DCIS) is an established precursor of invasive breast carcinoma. Immunoperoxidase stains for selected markers can assist pathologists in the diagnosis of challenging ductal epithelial proliferations, but they cannot replace morphologic evaluation as the primary and critical assessment of this disease. Molecular studies provide further insight into how DCIS progresses to invasive carcinoma and also confirm the heterogeneity of this lesion. Morphology-based knowledge, immunohistochemistry, and molecular advances in DCIS are the subjects of this review.

Atypical ductal hyperplasia: interobserver and intraobserver variability

Interobserver reproducibility in the diagnosis of benign intraductal proliferative lesions has been poor. The aims of the study were to investigate the inter- and intraobserver variability and the impact of the addition of an immunostain for high- and low-molecular weight keratins on the variability. Nine pathologists reviewed 81 cases of breast proliferative lesions in three stages and assigned each of the lesions to one of the following three diagnoses: usual ductal hyperplasia, atypical ductal hyperplasia and ductal carcinoma in situ. Hematoxylin and eosin slides and corresponding slides stained with ADH-5 cocktail (cytokeratins (CK) 5, 14. 7, 18 and p63) by immunohistochemistry were evaluated. Concordance was evaluated at each stage of the study. The interobserver agreement among the nine pathologists for diagnosing the 81 proliferative breast lesions was fair (κ-value=0.34). The intraobserver κ-value ranged from 0.56 to 0.88 (moderate to strong). Complete agreement among nine pathologists was achieved in only nine (11%) cases, at least eight agreed in 20 (25%) cases and seven or more agreed in 38 (47%) cases. Following immunohistochemical stain, a significant improvement in the interobserver concordance (overall κ-value=0.50) was observed (P=0.015). There was a significant reduction in the total number of atypical ductal hyperplasia diagnosis made by nine pathologists after the use of ADH-5 immunostain. Atypical ductal hyperplasia still remains a diagnostic dilemma with wide variation in both inter- and intraobserver reproducibility among pathologists. The addition of an immunohistochemical stain led to a significant improvement in the concordance rate. More importantly, there was an 8% decrease in the number of lesions classified as atypical ductal hyperplasia in favor of usual hyperplasia; in clinical practice, this could lead to a decrease in the number of surgeries carried out for intraductal proliferative lesions.

Imaging features of carcinoid tumors metastatic to the breast

The objective of this study was to describe the imaging findings of carcinoid tumors metastatic to the breast, with pathologic and clinical correlations. We searched our surgical database for cases of pathologically proven carcinoid tumors metastatic to the breast from October 1, 2000, to May 31, 2010. Of the approximate 10,000 breast biopsies identified, 7000 had malignant findings. Ten cases of metastatic carcinoid (0.1% of all malignancies), all with imaging studies available for review, were included in the study. All patients were women and had their primary carcinoid in the gastrointestinal tract (n=9) or lung (n = 1). One patient presented with a palpable breast mass and no history of carcinoid tumor; an ileal carcinoid was discovered after the pathologic diagnosis of metastatic carcinoid was established. In the breast, tumors presented as solitary lesions in half the cases. Metastases to the breast typically presented as circumscribed masses mammographically and as hypoechoic circumscribed masses ultrasonographically; some showed increased through-transmission and increased vascularity with color Doppler evaluation. Five patients had octreotide scans; of these, 4 had increased focal activity in the region of metastasis within the breast. Six patients underwent computed tomography. Without contrast, nodular masses were observed; with contrast, the masses showed rapid enhancement during arterial phase imaging. Magnetic resonance imaging (n = 4) also showed rapid enhancement and washout kinetics after contrast administration. Recognition of carcinoid metastases to the breast in patients with known or occult primary carcinoid tumors is important to avoid unnecessary treatment for primary breast cancer.

Cystadenocarcinoma simulating hemangiosarcoma of the salivary gland in dog: case report

Cystadenocarcinoma is regarded as a rare adenocarcinoma variant in animals. This work reports the case of an 8-year-old female Poodle dog with salivary gland cystadenocarcinoma with morphological characteristics similar to a hemangiosarcoma. Histopathological analysis showed a tumor mass with cystic formations containing a large amount of red blood cells. In order to distinguish these two entities, periodic acid Schiff (PAS) staining and immunohistochemical analysis were carried out with the use of cytokeratin AE1/AE3 (CK) and CD31-specific antibodies. Neoplastic cells were PAS-negative, CK-positive and CD31-negative confirming their epithelial origin. Based on the findings, the diagnosis of high grade cystadenocarcinoma was established.

Automation of immunohistochemical evaluation in breast cancer using image analysis

AIM: To automate breast cancer diagnosis and to study the inter-observer and intra-observer variations in the manual evaluations.

METHODS: Breast tissue specimens from sixty cases were stained separately for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2/neu). All cases were assessed by manual grading as well as image analysis. The manual grading was performed by an experienced expert pathologist. To study inter-observer and intra-observer variations, we obtained readings from another pathologist as the second observer from a different laboratory who has a little less experience than the first observer. We also took a second reading from the second observer to study intra-observer variations. Image analysis was carried out using in-house developed software (TissueQuant). A comparison of the results from image analysis and manual scoring of ER, PR and HER-2/neu was also carried out.

RESULTS: The performance of the automated analysis in the case of ER, PR and HER-2/neu expressions was compared with the manual evaluations. The performance of the automated system was found to correlate well with the manual evaluations. The inter-observer variations were measured using Spearman correlation coefficient r and 95% confidence interval. In the case of ER expression, Spearman correlation r = 0.53, in the case of PR expression, r = 0.63, and in the case of HER-2/neu expression, r = 0.68. Similarly, intra-observer variations were also measured. In the case of ER, PR and HER-2/neu expressions, r = 0.46, 0.66 and 0.70, respectively.

CONCLUSION: The automation of breast cancer diagnosis from immunohistochemically stained specimens is very useful for providing objective and repeatable evaluations.

Cytomorphology of male breast lesions: diagnostic pitfalls and clinical implications

Because lesions of the male breast have been exceeded in number by those of the female breast, marginal attention was given to these lesions in the past. Fortunately, this has changed over the years leading to an increased awareness about male breast cancer. Although male breast cancer constitutes only about 1% of all diagnosed breast cancer cases, an increased mortality is seen in this patient population. This is probably caused by late diagnosis as a consequence of low level of concern about breast cancer among male patients. However, the vast majority of lesions of the male breast are benign, gynecomastia being the number one cause of unilateral or bilateral breast mass. Since it is important to avoid unnecessary surgical treatment without missing malignancy, accurate diagnostic tools are necessary in order to triage these patients. Fine-needle aspiration biopsy has demonstrated excellent accuracy in the diagnosis and management of breast lesions in female patients. In addition, several authors have proven the value of this technique in the evaluation of lesions of the male breast. Fine-needle aspiration biopsy permits accurate diagnosis in many lesions arising in the male breast. It also allows gathering cytological material that can be used for ancillary studies which enhances the diagnostic value of this technique.

The ability to generate senescent progeny as a mechanism underlying breast cancer cell heterogeneity

BACKGROUND

Breast cancer is a remarkably heterogeneous disease. Luminal, basal-like, "normal-like", and ERBB2+ subgroups were identified and were shown to have different prognoses. The mechanisms underlying this heterogeneity are poorly understood. In our study, we explored the role of cellular differentiation and senescence as a potential cause of heterogeneity.

METHODOLOGY/PRINCIPAL FINDINGS

A panel of breast cancer cell lines, isogenic clones, and breast tumors were used. Based on their ability to generate senescent progeny under low-density clonogenic conditions, we classified breast cancer cell lines as senescent cell progenitor (SCP) and immortal cell progenitor (ICP) subtypes. All SCP cell lines expressed estrogen receptor (ER). Loss of ER expression combined with the accumulation of p21(Cip1) correlated with senescence in these cell lines. p21(Cip1) knockdown, estrogen-mediated ER activation or ectopic ER overexpression protected cells against senescence. In contrast, tamoxifen triggered a robust senescence response. As ER expression has been linked to luminal differentiation, we compared the differentiation status of SCP and ICP cell lines using stem/progenitor, luminal, and myoepithelial markers. The SCP cells produced CD24+ or ER+ luminal-like and ASMA+ myoepithelial-like progeny, in addition to CD44+ stem/progenitor-like cells. In contrast, ICP cell lines acted as differentiation-defective stem/progenitor cells. Some ICP cell lines generated only CD44+/CD24-/ER-/ASMA- progenitor/stem-like cells, and others also produced CD24+/ER- luminal-like, but not ASMA+ myoepithelial-like cells. Furthermore, gene expression profiles clustered SCP cell lines with luminal A and "normal-like" tumors, and ICP cell lines with luminal B and basal-like tumors. The ICP cells displayed higher tumorigenicity in immunodeficient mice.

CONCLUSIONS/SIGNIFICANCE

Luminal A and "normal-like" breast cancer cell lines were able to generate luminal-like and myoepithelial-like progeny undergoing senescence arrest. In contrast, luminal B/basal-like cell lines acted as stem/progenitor cells with defective differentiation capacities. Our findings suggest that the malignancy of breast tumors is directly correlated with stem/progenitor phenotypes and poor differentiation potential.

Quantification of metabolites in breast cancer patients with different clinical prognosis using HR MAS MR spectroscopy

Absolute quantitative measures of breast cancer tissue metabolites can increase our understanding of biological processes. Electronic REference To access In vivo Concentrations (ERETIC) was applied to high resolution magic angle spinning MR spectroscopy (HR MAS MRS) to quantify metabolites in intact breast cancer samples. The ERETIC signal was calibrated using solutions of creatine and TSP. The largest relative errors of the ERETIC method were 8.4%, compared to 4.4% for the HR MAS MRS method using TSP as a standard. The same MR experimental procedure was applied to intact tissue samples from breast cancer patients with clinically defined good (n = 13) and poor (n = 16) prognosis. All samples were examined by histopathology for relative content of different tissue types and proliferation index (MIB-1) after MR analysis. The resulting spectra were analyzed by quantification of tissue metabolites (β-glucose, lactate, glycine, myo-inositol, taurine, glycerophosphocholine, phosphocholine, choline and creatine), by peak area ratios and by principal component analysis. We found a trend toward lower concentrations of glycine in patients with good prognosis (1.1 µmol/g) compared to patients with poor prognosis (1.9 µmol/g, p = 0.067). Tissue metabolite concentrations (except for β-glucose) were also found to correlate to the fraction of tumor, connective, fat or glandular tissue by Pearson correlation analysis. Tissue concentrations of β-glucose correlated to proliferation index (MIB-1) with a negative correlation factor (-0.45, p = 0.015), consistent with increased energy demand in proliferating tumor cells. By analyzing several metabolites simultaneously, either in ratios or by metabolic profiles analyzed by PCA, we found that tissue metabolites correlate to patients' prognoses and health status five years after surgery. This study shows that the diagnostic and prognostic potential in MR metabolite analysis of breast cancer tissue is greater when combining multiple metabolites (MR Metabolomics).