Apocrine ductal carcinoma in situ of the breast: histologic classification and expression of biologic markers

Apocrine lesions of the breast

Apocrine change is recognised in benign, atypical and malignant lesions of the breast. Apocrine metaplasia, a frequent finding in the breast of women over the age of 25 years, is most commonly seen in benign cysts with a simple or papillary configuration. Apocrine change is also recognised in other benign lesions including sclerosing adenosis, now known as apocrine adenosis. Apocrine atypia usually refers to cytological atypia in which there is at least threefold variation in nuclear size but architectural atypia may also occur. The distinction between atypical apocrine hyperplasia and non-high-grade apocrine ductal carcinoma in situ may be difficult due to the relative rarity of these entities and the lack of validated diagnostic criteria. Lobular carcinoma in situ (LCIS) with apocrine change is considered to be a variant of pleomorphic LCIS. An apocrine variant of encapsulated papillary carcinoma is also recognised. Apocrine change is described in invasive carcinoma, including no special type, lobular, micropapillary and mucinous variants. The recent WHO 2019 update recognises 'carcinoma with apocrine differentiation' as a special type breast carcinoma based on the presence of apocrine morphology in at least 90% of the tumour. Tumours with apocrine morphology are usually but not always hormone receptor negative. Human epidermal growth factor receptor 2 (HER-2) status is variable. Molecular studies have identified breast tumours with apocrine features and high expression of androgen receptor mRNA including 'luminal androgen receptor tumours' and 'molecular apocrine tumours'. The term 'pure apocrine carcinoma' has been proposed to describe an invasive carcinoma with apocrine morphology that is oestrogen and progesterone receptor negative and androgen receptor positive. HER-2 status may be positive or negative. This article reviews the pathology of benign, atypical and malignant apocrine lesions of the breast, with emphasis on diagnostic criteria including an approach to evaluation of apocrine lesions on needle core biopsy, and recent advances in our understanding of invasive apocrine carcinoma.

Sclerosing Polycystic Adenoma: Conclusive Clinical and Molecular Evidence of Its Neoplastic Nature

Sclerosing polycystic adenosis, initially considered a non-neoplastic salivary gland lesion and classified as such in the 2017 WHO Classification of Head and Neck Tumors, has been the subject of controversy regarding its possible neoplastic nature. The reporting of recurrent PI3K pathway alteration represents evidence to support these lesions as being neoplastic and more appropriately referred to as sclerosing polycystic adenoma (SPA). Herein, we provide additional evidence that supports the classification of SPA as a true neoplasm. Eight cases of SPA were identified in our database and consultation files. All cases were subjected to PTEN immunohistochemistry (IHC) and next-generation sequencing (NGS). In addition, one patient underwent genetic counseling and germline testing. The cases included 5 men and 3 women with a mean age of 41 years (range 11-78) and all tumors arose in the parotid gland. One patient had multiple recurrences over a period of 2 years. Morphologically the tumors were circumscribed and characterized by an admixture of acini, ducts and cysts embedded in a fibrotic/sclerotic stroma. The cells lining the ducts and cysts showed variable granular, vacuolated, foamy and apocrine cytoplasmic features, as well as acinar cells contained intracytoplasmic brightly eosinophilic granules. The apocrine intraductal proliferations showed mild to moderate atypia in 6 cases. One case showed overt malignant morphology that ranged from intraductal carcinoma to invasive salivary duct carcinoma. Seven cases tested for PTEN IHC showed loss of nuclear expression in the acinar and ductal cells with retained PTEN expression in the myoepithelial cell and stroma. NGS detected PIK3CA or PIK3R1 genetic alterations in 7 cases, including a novel TFG-PIK3CA fusion. Coexisting PTEN mutations were seen in 4 cases, including in a patient with clinical stigmata of Cowden syndrome and confirmed by germline genetic testing. Our findings herein documented including recurrence of tumor, malignant transformation, high prevalence of PI3K pathway oncogenic alterations and the possible heretofore undescribed association with Cowden syndrome add support to classifying SPA as true neoplasms justifying their designation as adenoma, rather than adenosis.

Apocrine ductal carcinoma in situ associated with testosterone therapy in a transgender individual

We report the first case of apocrine ductal carcinoma in situ (DCIS) in a female-to-male transgender individual on testosterone therapy (TT). The gender confirmation total mastectomy revealed 2 cm DCIS with apocrine cytology, high nuclear grade with associated calcification, and necrosis. Immunohistochemistry revealed the DCIS was negative for ER, positive for AR with HER2/neu overexpression (3+). This patient with negative screening mammography developed apocrine DCIS on TT, suggesting that gender-affirming hormone therapy may have advanced malignant transformation of atypical apocrine cells. This may have implications for increased surveillance within the transgender population.

Breast Atypical Apocrine Adenosis: A Case Report and Literature Review

Atypical apocrine adenosis (AAA) is a benign lesion of the breast that is identified more frequently today than in the past when it was considered a rare diagnosis and commonly misdiagnosed as other malignant lesions of the breast. AAA is defined as the presence of apocrine cytology in a recognisable lobular unit associated with sclerosing adenosis. We present a case of an incidental finding of AAA and discuss diagnostic challenges and their implications on clinical management.

Apocrine lesions of the breast: part 2 of a two-part review. Invasive apocrine carcinoma, the molecular apocrine signature and utility of immunohistochemistry in the diagnosis of apocrine lesions of the breast

Pure apocrine carcinoma of the breast is rare and has been defined by using a combination of morphologic (apocrine morphology in >90% of tumour cells) and immunohistochemical criteria (oestrogen receptor (ER) and progesterone receptor (PR) negative and androgen receptor (AR) positive). Recent advances in the molecular classification of breast tumours have uncovered a subset of breast tumours associated with high expression of androgen receptor mRNA including the so-called 'luminal androgen receptor (LAR) tumours' and 'molecular apocrine tumours' (MATs). Recognition of these tumour subsets has opened potential avenues for therapies exploiting the AR pathway in triple negative breast carcinoma (TNBC). In this second part of our two-part review, we focus on the definition of pure apocrine carcinoma, recent advances in understanding the molecular apocrine signature in breast carcinoma, its relationship to pure apocrine carcinoma defined at the level of light microscopy and immunohistochemistry (IHC) and the therapeutic implications of androgen expression in TNBC. We complete the article with a summary of the utility of IHC in stratifying apocrine lesions of the breast.

Apocrine lesions of the breast: part 1 of a two-part review: benign, atypical and in situ apocrine proliferations of the breast

Apocrine morphology is a common phenomenon encountered in everyday breast pathology practice, and is defined as cuboidal or columnar cells exhibiting abundant eosinophilic granular cytoplasm, prominent apical granules, a low nuclear-cytoplasmic ratio, and round nuclei with pale chromatin and prominent nucleoli. Apocrine morphology is recognised in benign, atypical and malignant lesions of the breast. The morphology of apocrine atypia and non-high-grade apocrine ductal carcinoma in situ (DCIS) is less well defined due to the relative rarity of these lesions. In part 1 of this two-part review, we focus on the morphological characteristics of benign, atypical and in situ apocrine lesions of the breast, summarise the available data to date regarding distinction of atypical apocrine proliferations from non-high-grade apocrine DCIS and the biological significance of apocrine atypia, and provide practical guidance on handling these difficult lesions. Part 2 of this review will focus on the concept of pure apocrine carcinoma with emphasis on its definition and molecular data, including the current understanding of the molecular apocrine signature in breast carcinoma. We complete the review with a synopsis on the utility of immunohistochemistry in the diagnosis of apocrine lesions of the breast.

Atypical Apocrine Adenosis: Diagnostic Challenges and Pitfalls

Apocrine change in the breast is an extremely common finding. In most cases, the benign or malignant nature of the lesion is easily recognized. Apocrine adenosis is used to describe sclerosing adenosis with apocrine change. The term apocrine atypia is used when there is significant cytologic atypia in apocrine cells, characterized by a 3-fold nuclear enlargement, prominent/multiple nucleoli, and hyperchromasia. Atypical apocrine adenosis is diagnosed when apocrine adenosis and apocrine atypia are superimposed. However, there are no definite criteria to distinguish atypical apocrine adenosis from apocrine ductal carcinoma in situ. Immunohistochemical markers can be confounding and may lead to erroneous diagnoses. Atypical apocrine features in sclerosing lesions may be misinterpreted as invasive carcinoma if the underlying lesion is not recognized. In the absence of definite features of malignancy, the diagnosis of apocrine ductal carcinoma in situ may be extremely difficult. In the present article, we review atypical apocrine adenosis focusing on diagnostic challenges and their implications on clinical management.

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.

Evaluation of Estrogen, Progesterone, and GCDFP-15 Expression in Uterine Leiomyomas

Approximately, one fourth of women have leiomyomas. Leiomyomas are benign tumors that originated from smooth muscle cells. Estrogen is claimed to relate as a cause but exact mechanism has not fully understood. In this study, 95 leiomyoma cases that have been diagnosed by our department in years between 2010 and 2012 were examined. Age ranges of patients, sizes, locations, and numbers of leiomyomas were identified. Immunohistochemically ER (estrogen), PR (progesterone), and Gross cystic disease fluid protein-15 stains were performed to the paraffin blocks and their percentages of staining were noted. Statistically, submucosal and intramural locations were significantly related to ER and PR (p < 0,001). There were significant relationship between ER and PR in 30-50 years age group (p < 0,001). There were significant relationship between ER, PR and locations (p < 0,001), numbers (p < 0,001), sizes of leiomyomas (below 5 cm; p < 0,001), (between 5 and 10 cm; p = 0,037), larger than 10 cm; p = 0,002). Consequently, relationship between leiomyoma and ER, PR were revealed in this study. Also, relationship between leiomyoma locations and patient ages were identified statistically. There was no immunoreactivity with GCDFP-15 in leiomyomas.

High level PHGDH expression in breast is predominantly associated with keratin 5-positive cell lineage independently of malignancy

We have previously reported the 2D PAGE-based proteomic profiling of a prospective cohort of 78 triple negative breast cancer (TNBC) patients, and the establishment of a cumulative TNBC protein database. Analysis of this database identified a number of proteins as being specifically overexpressed in TNBC samples. One such protein was D-3-phosphoglycerate dehydrogenase (Phgdh), a candidate oncogene. We analysed expression of Phgdh in normal and TNBC mammary tissue samples by 2D gel-based proteomics and immunohistochemistry (IHC), and show here that high-level expression of Phgdh in mammary epithelial cells is primarily associated with cell lineage, as we found that Phgdh expression was predominant in CK5-positive cells, normal as well as malignant, thus identifying an association of this protein with the basal phenotype. Quantitative IHC analysis of Phgdh expression in normal breast tissue showed high-level expression of Phgdh in normal CK5-positive mammary epithelial cells, indicating that expression of this protein was not associated with malignancy, but rather with cell lineage. However, proteomic profiling of Phgdh showed it to be expressed in two major protein forms, and that the ratio of expression between these variants was associated with malignancy. Overexpression of Phgdh in CK5-positive cell lineages, and differential protein isoform expression, was additionally found in other tissues and cancer types, suggesting that overexpression of Phgdh is generally associated with CK5 cells, and that oncogenic function may be determined by isoform expression.

Cystic apocrine ductal carcinoma in situ with increased EGFR expression, trisomy 7, and associated focal invasion

A 71-year-old woman was admitted to our hospital with a lump in her right breast. Mammography revealed an internal high-density mass in the lower right breast, which was larger than it was 2 years ago. Considering the findings from ultrasonography, computed tomography, and cytology, an intracystic carcinoma could not be ruled out. The patient underwent excisional biopsy, which revealed an apocrine ductal carcinoma in situ (ADCIS) with focal invasive apocrine carcinoma (IAC). The diagnosis was based on morphology and immunohistochemistry (IHC), which was negative for the estrogen and progesterone receptors, and positive for the androgen receptor. Expression of the human epidermal growth factor receptor 2 and the epidermal growth factor receptor (EGFR) received an immunohistochemical score of 2+. Trisomy of chromosome 7, including multiple CEP 7 and EGFR signals, was observed in ADCIS by fluorescence in situ hybridization (FISH). IAC exhibited similar results for IHC and FISH. This is the first reported case showing trisomy 7 resulting in EGFR copy number gain and increased EGFR expression in ADCIS.

Molecular mapping the presence of druggable targets in preinvasive and precursor breast lesions: a comprehensive review of biomarkers related to therapeutic interventions

The analysis of clinical breast samples using biomarkers is integral to current breast cancer management. Currently, a limited number of targeted therapies are standard of care in breast cancer treatment. However, these targeted therapies are only suitable for a subset of patients and resistance may occur. Strategies to prevent the occurrence of invasive lesions are required to reduce the morbidity and mortality associated with the development of cancer. In theory, application of targeted therapies to pre-invasive lesions will prevent their progression to invasive lesions with full malignant potential. The diagnostic challenge for pathologists is to make interpretative decisions on early detected pre-invasive lesions. Overall, only a small proportion of these pre-invasive lesions will progress to invasive carcinoma and morphological assessment is an imprecise and subjective means to differentiate histologically identical lesions with varying malignant potential. Therefore differential biomarker analysis in pre-invasive lesions may prevent overtreatment with surgery and provide a predictive indicator of response to therapy. There follows a review of established and emerging potential druggable targets in pre-invasive lesions and correlation with lesion morphology.

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.

Immunohistochemically defined subtypes and outcome of apocrine breast cancer

BACKGROUND

Conflicting data are available in the literature on the outcome of invasive apocrine carcinoma (IAC), possibly related to a heterogeneous classification of these tumors.

PATIENTS AND METHODS

A series of 6899 consecutive patients with invasive ductal carcinoma (IDC) not otherwise specified and 72 patients with immunohistochemically defined IAC who received surgery at the European Institute of Oncology between 1997 and 2005 were included. We then explored patterns of recurrence of IAC according to 2 immunohistochemically defined tumor subtypes: pure apocrine carcinoma (estrogen [ER] and progesterone [PgR] receptor negative, and AR positive) and apocrine-like carcinoma (ER or PgR positive and AR negative).

RESULTS

The diagnosis of pure apocrine carcinoma was correlated with a worse outcome in terms of DFS (hazard ratio [HR] 1.7; 95% confidence interval [CI], 1.01-2.86; P = .0010) if compared with IDC, whereas IDC and apocrine-like breast cancers showed a similar outcome in terms of DFS and overall survival. Patients with pure apocrine carcinoma had an increased risk in contralateral breast cancer (HR, 4.12; 95% CI, 1.22-14; P = .02).

CONCLUSION

Pure apocrine carcinoma represents a distinct subtype of breast cancer with a significantly worse DFS as compared with IDC. AR determination might have an important prognostic implication in IAC. Moreover, AR-targeted therapy should be further explored within these tumors.

HER-2 expression in canine morphologically normal, hyperplastic and neoplastic mammary tissues and its correlation with the clinical outcome

The proto-oncogene HER-2/neu (c-erbB-2) encodes a transmembrane receptor protein with tyrosine-kinase activity. Previous studies have shown that HER-2 protein over-expression is present in canine mammary tumours, however, possible prognostic and predictive analogies between protein over-expression patterns in canine and human species are still controversial. Thirty-five canine mammary carcinomas, 11 mammary adenomas, and normal, hyperplastic or dysplastic tissues taken at the marginal area of the tumours were evaluated by immunohistochemistry (IHC) for HER-2 expression, using the Hercept Test® system scoring guidelines. HER-2 over-expression was detected in 3/11 adenomas and 10/35 carcinomas. Normal, hyperplastic and dysplastic mammary tissues were also found to be positive. The correlations between HER-2 expression and tumour histological grading, mitotic index, the presence of lymphatic invasion, and overall survival (OS) were evaluated. In carcinomas, HER-2 positive status only correlated with the mitotic index. A positive correlation was also found between HER-2 positive status and the presence of HER-2 over-expression in normal, hyperplastic or/and dysplastic mammary tissues surrounding the tumours. The percentage of HER-2 over-expressing tumours was similar to the percentage previously observed in canine benign and malignant mammary tumours. However an investigation regarding morphologically normal and hyperplastic or dysplastic tissues surrounding neoplastic lesions also showed HER-2 over-expression. In contrast with human mammary tumours, this study confirmed that in canine species, HER-2 over-expression does not identify a subgroup of tumours with a poor prognosis. In fact, we found HER-2 over-expression in morphologically non-neoplastic mammary tissues, surrounding hyperplastic and neoplastic lesions.

Atypical apocrine adenosis of the breast: long-term follow-up in 37 patients

CONTEXT

Atypical apocrine adenosis is a rare breast lesion in which the cellular population demonstrates cytologic alterations that may be confused with malignancy. The clinical significance and management of atypical apocrine adenosis are unclear because of the lack of long-term follow-up studies.

OBJECTIVE

To determine the breast cancer risk in a retrospective series of patients with atypical apocrine adenosis diagnosed in otherwise benign, breast excisional biopsies.

DESIGN

We identified 37 atypical apocrine adenosis cases in the Mayo Benign Breast Disease Cohort (9340 women) between 1967 and 1991 with a blinded pathology rereview. Breast cancer diagnoses subsequent to initial atypical apocrine adenosis biopsy were identified (average follow-up, 14 years).

RESULTS

The mean age at diagnosis of atypical apocrine adenosis in the group was 59 years. Breast carcinoma subsequently developed in 3 women (8%) with atypical apocrine adenosis, diagnosed after follow-up intervals of 4, 12, and 18 years. The tumor from 1 of the 3 cases (33%) was ductal carcinoma in situ, contralateral to the original biopsy, and the other 2 cases (66%) were invasive carcinoma. Ages at the time of diagnosis of atypical apocrine adenosis were 55, 47, and 63 years for those that developed in situ or invasive carcinoma.

CONCLUSIONS

(1) Atypical apocrine adenosis was a rare lesion during the accrual era of our cohort (<1% of cases); (2) women found to have atypical apocrine adenosis were, on average, older than were other patients with benign breast disease, however, there does not seem to be an association with age and risk for developing carcinoma in patients diagnosed with atypical apocrine adenosis, as previously suggested; and (3) atypical apocrine adenosis does not appear to be an aggressive lesion and should not be regarded as a direct histologic precursor to breast carcinoma.

Androgen receptor expression is usually maintained in initial surgically resected breast cancer metastases but is often lost in end-stage metastases found at autopsy

Androgen receptor (AR) is expressed in approximately 70% of primary breast carcinomas (PBCs) and is a promising therapeutic target for metastatic breast carcinoma (MBC). Here, we examine AR expression in a population of initial surgically resected metastases and a separate cohort of end-stage metastases harvested at autopsy compared with their matched PBCs. Tissue microarrays of matched PBC and MBC were labeled by immunohistochemistry for AR, estrogen receptor (ER), progesterone receptor (PR), and Her2 and classified into the following previously described categories: luminal (ER/PR+/Her2-), triple negative (ER/PR/Her2-), Her2 (ER/PR-/Her2+), and luminal loss (ER/PR loss from primary to metastasis). In the cohort of surgically resected metastases (n = 16), AR was expressed in 12 of 16 PBC and maintained in 11 of 12 corresponding MBCs. Of these, 36% showed stronger AR labeling in the metastases and none showed a decrease. In the cohort of metastases harvested at autopsy (n = 16), AR was expressed in 11 of 16 primary carcinomas and maintained in only 5 of 11 corresponding metastases. Of these, none showed increased AR and 80% showed decreased AR labeling. AR expression is overwhelmingly concordant between matched PBC and MBC at initial presentation. These findings validate AR as a therapeutic target in MBC and suggest that AR may need to be reevaluated in metastases even if the primary is negative. However, similar to ER/PR, AR expression is often decreased with a trend toward complete loss in end-stage metastases, suggesting a shift of AR expression between initial and end-stage metastases. This suggests an opportunity for targeted antiandrogen therapy at an earlier stage of disease progression.

A non-invasive form of lipid-secreting carcinoma of the breast

Lipid-secreting carcinoma is a rare variant of breast carcinoma. The tumor cells possess abundant vacuolated cytoplasm containing neutral fat. A 68-year-old Japanese female patient presented with a left breast tumor, which was detected by mass screening, and she was admitted to our hospital. The physical examination revealed an elastic hard lump in the left lateral quadrant of the left breast. The tumor size was 1.2 × 1.0 cm in diameter and the borderline was unclear. There were no palpable axillary lymph nodes or supraclavicular nodes. Mammography showed a polygonal mass with microcalcification. Ultrasonography indicated a hypoechoic lesion measuring 9 × 4 mm in diameter, with an irregularly shaped, slightly indistinct surface. The internal echoic level of the mass was heterogenous. Enhanced magnetic resonance imaging revealed a mass of high intensity in the left breast, and the connection of the intraductal spread was not detected. The time-intensity curve showed a peak-and-plateau pattern. Fine-needle aspiration cytology suggested a malignant tumor. The patient underwent a partial resection of the left breast (breast-conserving therapy) and a left axillary lymphadenectomy. Macroscopically, the resected specimen revealed a white tumor measuring approximately 0.6 × 0.5 cm. Histopathologically, the tumor measured up to approximately 0.9 × 0.7 cm because of additional components of intraductal spread and therefore was diagnosed as an extensive ductal carcinoma in situ with focal mass formation; the tumor also had abundant foamy cytoplasm. Oil-red-O staining confirmed the presence of marked cytoplasmic lipid droplets. These droplets were periodic acid-Schiff (PAS) negative even after diastase digestion, and negative with PAS-Alcian blue staining. In immunohistochemistry, these carcinoma cells were positive for E-cadherin. Thus, the pathological diagnosis was a non-invasive form of lipid-secreting carcinoma. The tumors were negative for both estrogen receptors and progesterone receptors. There were no metastases in the left axillary lymph nodes. The patient has remained well for 8 years without any evidence of recurrence.

Breast cancer molecular class ERBB2: preponderance of tumors with apocrine differentiation and expression of basal phenotype markers CK5, CK5/6, and EGFR

This is a study of 205 consecutive invasive breast carcinomas. The principal aim was to identify morphologic and immunohistochemical features of tumors that belong to the molecular class ERBB2. The invasive breast carcinomas were classified using semiquantitative immunohistochemical results for estrogen receptor (ER), progesterone receptor, (PR), and HER2 into following classes: Luminal A (strong ER+, HER2 negative), Luminal B (weak to moderate ER/PR+, HER2 negative), Triple Negative (TN; ER/PR negative, HER2 negative), ERBB2 (ER/PR negative, HER2 positive), Luminal A-HER2 Hybrid (strong ER+, HER2 positive), Luminal B-HER2 Hybrid (weak to moderate ER/PR+, HER2 positive). Of the 205 tumors, 113 (55%) were classified as Luminal A, 34 (17%) as Luminal B, 32 (15%) as TN, 8 (4%) as ERBB2, 10 (5%) as Luminal A-HER2 Hybrid, and 8 (4%) as Luminal B-HER2 Hybrid. Majority of the ERBB2 tumors were high grade as expected, with average Nottingham score of 8. Moderate lymphoid infiltrate (constituting 25% to 50% of the tumor) was seen in 5 of 8 (63%) cases and necrosis in 3 of 8 (38%) cases. The most striking morphologic feature associated with ERBB2 tumors was the presence of apocrine differentiation seen in 7 of 8 (88%) cases. CK5 immunoreactivity was seen in 5 of 8 cases (63%). Epidermal growth factor receptor staining with 2+ or 3+ score was also seen in 5 cases (63%). Due to low prevalence of ERBB2 tumors, additional data set of 191 cases enriched in ERBB2 and TN tumors was used for confirmation of morphologic findings. We conclude that tumors with apocrine differentiation are most often of ERBB2 type. ERBB2 tumors demonstrate some features classically ascribed to TN basal-like tumors. Epidermal growth factor receptor overexpression in ERBB2 tumors may have additional predictive value.

EGFR and HER-2/neu expression in invasive apocrine carcinoma of the breast

This study was undertaken to investigate epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER-2)/neu expression in a cohort of apocrine carcinomas of the breast with emphasis on the classification of the breast tumors with apocrine morphology. In total, 55 breast carcinomas morphologically diagnosed as apocrine were evaluated for the steroid receptor expression profile characteristic of normal apocrine epithelium (androgen receptor positive/estrogen receptor (ER) negative/progesterone receptor (PR) negative), and for the expression of EGFR and Her-2/neu proteins, and the copy number ratios of the genes EGFR/CEP7 and HER-2/CEP17. On the basis of the results of steroid receptors expression, 38 (69%) cases were classified as pure apocrine carcinoma (androgen receptor positive/ER negative/PR negative), whereas 17 (31%) were re-classified as apocrine-like carcinomas because they did not have the characteristic steroid receptor expression profile. Her-2/neu overexpression was observed in 54% of the cases (57% pure apocrine carcinomas vs 47% apocrine-like carcinomas). HER-2/neu gene amplification was demonstrated in 52% of all cases (54% pure apocrine carcinomas vs 46% apocrine-like carcinomas). EGFR protein (scores 1 to 3+) was detected in 62% of all cases and was expressed in a higher proportion of pure apocrine carcinomas than in the apocrine-like carcinomas group (76 vs 29%, P=0.006). In the pure apocrine carcinoma group, Her-2/neu and EGFR protein expression were inversely correlated (P=0.006, r=-0.499). EGFR gene amplification was observed in two pure apocrine carcinomas and one apocrine-like carcinoma. Polysomy 7 was commonly present in pure apocrine carcinomas (61 vs 27% of apocrine-like carcinomas; P=0.083) and showed a weak positive correlation with EGFR protein expression (P=0.025, r=0.326). Our study showed that apocrine breast carcinomas are molecularly diverse group of carcinomas. Strictly defined pure apocrine carcinomas are either HER-2-overexpressing breast carcinomas or triple-negative breast carcinomas, whereas apocrine-like carcinomas predominantly belong to the luminal phenotype. Pure apocrine carcinomas show consistent overexpression of either EGFR or HER-2/neu, which could have significant therapeutic implications.

Cell turnover in apocrine metaplasia and apocrine adenosis of the breast

Apocrine metaplasia (APM) is a common finding in the breast of postmenopausal women and is seen in a broad spectrum of lesions ranging from microscopic cysts to invasive apocrine carcinoma. Apocrine metaplasia within sclerosing adenosis is known as apocrine adenosis (AA) and is considered a benign lesion of the breast. Apocrine metaplasia and AA have been the subject of many studies; however, little is known about the dynamics of cell turnover in these lesions. Recent studies have shown that some forms of AA may show altered degree of proliferation along with altered expression of bcl-2 and bax proteins. In the current study, we investigate further aspects of apoptosis to help understand the mechanisms of cell turnover in AA and APM. To investigate cell turnover in APM and AA, immunohistochemistry was used to study the expression of the apoptotic markers Bak, Mcl-1, Bcl-x, and Bcl-x(L) in 45 cases of APM (13 cases of nonpapillary APM, 21 cases of simple papillary APM, and 11 cases of complex papillary APM). Also, 34 cases of AA (23 cases of non-atypical AA [NAA] and 11 cases of atypical AA [AAA]) were included in the study. The expression of hTERT and the proliferation marker Ki-67 were also determined. The TdT-mediated dUTP nick-end labeling (TUNEL) technique was used to study the apoptotic status in 28 cases of APM (12 cases nonpapillary APM and 16 cases of papillary APM including simple and complex forms) and 22 cases of AA (15 cases of NAA and 7 cases of AAA). The results showed that all cases studied by immunohistochemistry were positive for the expression of Bak, Mcl-1, Bcl-x, and Bcl-x(L) showing a pattern of staining similar to that seen in the normal breast epithelium. There was no relation between hTERT positivity and the degree of proliferation in any of the lesions studied. The TUNEL results revealed an apoptotic index (AI) of 0.4% and 0.2% in the papillary and nonpapillary groups of APM, respectively. There was no statistical significance between the AI of these 2 groups and that of the normal breast epithelium (0.3%). The average Ki-67 index in the nonpapillary group was 0.7%, whereas in the papillary group, a value of 4% was recorded. In the cases of AA, an AI of 0.4% and 0.3% in NAA and AAA, respectively, was seen. There was no statistical significance between the AI of these 2 groups and that of the normal breast epithelium (0.3%). The Ki-67 index was 5.2% and 6.6% in the NAA and AAA, respectively. The current results show that apoptosis is not a common event in APM and AA even in the presence of increased proliferation, which may render some of these lesions more susceptible to oncogenic changes. Further studies are needed to study other apoptotic pathways that may be involved in cell turnover in these lesions.

Encapsulated apocrine papillary carcinoma of the breast--a tumour of uncertain malignant potential: report of five cases

Five cases of an unusual encapsulated apocrine papillary tumour are reported. All presented as cystic masses in the breast of women aged 44-84 years. Imaging studies showed a complex cyst often with one or more mural nodules. The key histological features are similar to those of classical encapsulated papillary carcinoma in that myoepithelial cells were absent within the papillary structures and at the periphery of the cyst. All were pure apocrine in type and showed variable degrees of cytological atypia and mitotic activity. All lacked evidence of malignancy in the breast tissue outside of the lesion. Sentinel lymph node biopsies performed in three of the cases were negative for metastases, and all have behaved in a benign fashion.

Oestrogen receptor-beta1 but not oestrogen receptor-betacx is of prognostic value in apocrine carcinoma of the breast

Apocrine carcinoma of the breast, which frequently expresses oestrogen receptor-beta (ER-beta) in the absence of ER-alpha and only infrequently is treated endocrinologically, gives an opportunity to investigate the clinicopathological role of ER-beta in breast cancer independent of ER-alpha expression or tamoxifen treatment. Several isotypes of ER-beta, ER-beta1-5 etc., have been identified thus far; however, the clinicopathological importance of each ER-beta isotype in breast cancer is still uncertain. Here we aimed to clarify the clinicopathological importance of ER-beta1 and ER-betacx (ER-beta2) in apocrine carcinomas, immunohistochemically examining expressions of ER-beta1 and ER-betacx in 47 apocrine carcinomas. Positivity for ER-beta1 and ER-betacx was observed in 41 (87%) and 18 (38%) of 47 cases, respectively. ER-beta1 positivity was related to smaller tumor size (P=0.0359), lower histological grade (P=0.0322), and higher disease-free survival (P<0.0001), whereas ER-betacx status was related to none of these parameters. ER-beta1 positivity was also associated with favorable clinical outcome in 24 so-called triple-negative (ER-alpha-negative/PR-negative/HER2-negative) apocrine carcinomas. ER-beta1 itself, independent of ER-alpha expression and tamoxifen treatment, seems to have a tumor-suppressive effect, at least in apocrine carcinomas. Further study of ER-beta1 is desired to optimize breast cancer treatment.

15-prostaglandin dehydrogenase expression alone or in combination with ACSM1 defines a subgroup of the apocrine molecular subtype of breast carcinoma

Established histopathological criteria divide invasive breast carcinomas into defined groups. Ductal of no specific type and lobular are the two major subtypes accounting for around 75 and 15% of all cases, respectively. The remaining 10% include rarer types such as tubular, cribriform, mucinous, papillary, medullary, metaplastic, and apocrine breast carcinomas. Molecular profiling technologies, on the other hand, subdivide breast tumors into five subtypes, basal-like, luminal A, luminal B, normal breast tissue-like, and ERBB2-positive, that have different prognostic characteristics. An additional subclass termed "molecular apocrine" has recently been described, but these lesions did not exhibit all the histopathological features of classical invasive apocrine carcinomas (IACs). IACs make up 0.5-3% of the invasive ductal carcinomas, and despite the fact that they are morphologically distinct from other breast lesions, there are presently no standard molecular criteria available for their diagnosis and as a result no precise information as to their prognosis. Toward this goal our laboratories have embarked in a systematic proteomics endeavor aimed at identifying biomarkers that may characterize and subtype these lesions as well as targets that may lead to the development of novel targeted therapies and chemoprevention strategies. By comparing the protein expression profiles of apocrine macrocysts and non-malignant breast epithelial tissue we have previously reported the identification of a few proteins that are specifically expressed by benign apocrine lesions as well as by the few IACs that were available to us at the time. Here we reiterate our strategy to reveal apocrine cell markers and present novel data, based on the analysis of a considerably larger number of samples, establishing that IACs correspond to a distinct molecular subtype of breast carcinomas characterized by the expression of 15-prostaglandin dehydrogenase alone or in combination with a novel form of acyl-CoA synthetase medium-chain family member 1 (ACSM1). Moreover we show that 15-prostaglandin dehydrogenase is not expressed by other breast cancer types as determined by gel-based proteomics and immunohistochemistry analysis and that antibodies against this protein can identify IACs in an unbiased manner in a large breast cancer tissue microarray making them potentially useful as a diagnostic aid.

An update on apocrine lesions of the breast

Apocrine change occurs in a spectrum of benign lesions in the female breast and is also demonstrated in a subgroup of in situ and invasive carcinomas. Recent research has focused on the molecular phenotype of both benign and malignant apocrine lesions. This review will briefly summarize the morphological characteristics and risk associations of the spectrum of apocrine proliferations, but will focus on the updated molecular studies of both in situ and invasive apocrine carcinomas.

Invasive apocrine carcinoma of the breast: clinicopathologic features of 57 patients

Apocrine carcinoma is a rare, unique, and morphologically distinctive type of invasive ductal carcinoma (IDC). The features of invasive apocrine carcinoma (IAC) and their possible prognostic implications have not been fully investigated. To this end, we examined the clinicopathologic characteristics and outcome of patients with IAC and compared these factors with those of patients with IDC. Out of 2,055 breast cancer patients who had undergone breast surgery between 1995 and 2005, 57 patients of IAC and 1,583 patients of IDC were analyzed. The mean ages of the patients with IAC and of those with IDC were 58.5 +/- 10.9 years and 54.4 +/- 11 years, respectively (p = 0.006). The percentages of patients with axillary nodal metastasis and lymphatic invasion were significantly lower in the IAC group than in the IDC group (p = 0.03 and 0.02, respectively). The percentage of estrogen and progesterone receptor negativity was higher in the IAC group than in the IDC group (p < 0.001). After a median follow-up period of 49 months (range, 1-133 months), seven (12%) patients with IAC and 244 (15%) patients with IDC had experienced recurrences. Three (5%) patients with IAC and 125 (8%) patients with IDC died of recurrent breast cancer. No significant differences in the relapse-free survival (p = 0.83) and overall survival (p = 0.75) rates were observed between the two groups. Although IAC and IDC have different clinicopathologic characteristics, the prognoses of patients with these diseases are similar.

Lack of expression of androgen receptor may play a critical role in transformation from in situ to invasive basal subtype of high-grade ductal carcinoma of the breast

Androgen receptor has been implicated in the pathogenesis of breast carcinoma. In this study, we explored the potential role of androgen receptor in breast cancer by analyzing its expression using immunohistochemistry and its relationship with tumor progress (ductal carcinoma in situ [DCIS] versus invasive ductal carcinoma [IDC]); nuclear grades (high grade [HG] versus non-high grade); expression of estrogen receptor (ER), progesterone receptor (PR), HER-2; and 3 molecular classifications: cytokeratin classification, triple (ER/PR/HER-2) negative classification, and ER/HER-2 classification in 184 breast carcinomas. We found that (1) lack of androgen receptor expression was associated with HG-IDC and with basal subtypes of HG-IDC, suggesting androgen receptor may play an important role in preventing the invasive transformation in this subgroup of breast carcinoma. (2) HG-IDC and HG-DCIS more frequently expressed androgen receptor than ER (55%-93% for androgen receptor and 18%-30% for ER) and were frequently androgen receptor+/ER- (63% for HG-DCIS and 39% for HG-IDC), which made androgen receptor a possible therapeutic target. (3) One third of HG-IDC was negative for androgen receptor, ER, PR, and HER-2, suggesting that further studies are needed to identify other key molecules for targeted therapy. We purpose that androgen receptor should be routinely measured for breast cancer.

Non-operative breast pathology: apocrine lesions

Apocrine metaplasia is a very common finding in the female breast after the age of 25. It is so common that many people regard it as a normal component of the breast. This, however, is only really the case in apocrine sweat glands of the axilla and in the peri-areolar apocrine glands. The apocrine cell does, however, contribute to a number of different breast lesions, some of which are very taxing diagnostically; apocrine variants of both in-situ and invasive cancer are encountered. This review considers the common apocrine metaplastic lesions seen in fibrocystic change as well as apocrine adenoma, apocrine change within sclerosing adenosis, atypical apocrine lesions and apocrine malignancies.

Expression of oestrogen receptor-? in apocrine carcinomas of the breast

AIMS

Apocrine carcinoma of the breast seldom expresses oestrogen receptors (ER) or progesterone receptors (PR), but frequently expresses androgen receptors (AR). Because of this unusual hormone receptor status, it has been suggested that oestrogens have a less important role in the pathogenesis of apocrine carcinoma. The ER status of apocrine carcinoma has been studied for one kind of ER, the classic receptor now named ER-alpha; however, the status of ER-beta, a secondary oestrogen receptor, has not been examined systematically in apocrine carcinoma. The aim was to study ER-beta status in apocrine carcinoma.

METHODS AND RESULTS

The expression of ER-beta was examined immunohistochemically in 48 apocrine carcinomas and compared with clinicopathological factors and ER-alpha, PR and AR status. ER-beta positivity was observed in 35 cases (73%), regardless of any clinicopathological factors or the status of other receptors. The results of ER-beta mRNA analysis supported the immunohistochemical results.

CONCLUSIONS

The significance of oestrogens in apocrine carcinoma should not be dismissed at present when the role of ER-beta remains to be determined. Studying the action of oestrogen or antioestrogen in apocrine carcinoma may reveal a role for ER-beta independent of ER-alpha and raise the potential of hormonal therapy for these tumours.

Low-grade Intraductal Carcinoma of Salivary Gland

Low-grade intraductal carcinomas (LG-IDCs) of salivary gland are rare neoplasms that resemble atypical ductal hyperplasia or LG-IDCs of the breast. They have been referred to as "low-grade salivary duct carcinomas" or "low-grade cribriform cystadenocarcinomas." Herein, we describe 3 additional cases of LG-IDCs, 2 were pure intraductal carcinomas, although 1 demonstrated increasing cytologic atypia and progression to an invasive adenosquamous carcinoma. The latter had been present for 7 years before demonstrating clinical and pathologic progression to a widely invasive malignancy. The intraductal component in all cases exhibited a remarkable degree of apocrine differentiation. The tumor cells were positive for AE1:AE3, Cam 5.2, high molecular weight keratin, CK7, CK19, BRST-2, and androgen receptors (ARs). S-100 was positive in 2 cases and negative in 1 case. The intraductal neoplastic cells were surrounded by myoepithelial cells positive for CK14, actins, calponin, high molecular weight keratin, and p63. All the tumors were negative for CK20, estrogen and progesterone receptors, Her2Neu, and p53. Extensive apocrine differentiation, expression of ARs, CK7, and CK19, and progression to a widely invasive carcinoma after a long clinical latency have not been reported in LG-IDCs previously. These tumors share some histopathologic features with salivary duct carcinoma including apocrine differentiation, and expression of ARs and BRST-2. The terms "low-grade salivary duct carcinomas" and "low-grade cribriform cystadenocarcinomas" should be abandoned in favor of LG-IDC of salivary gland, which better reflects their predominantly noninvasive, intraductal nature.

Expression of androgen receptors and inhibin/activin alpha and betaA subunits in breast apocrine lesions

The importance of androgens and their receptors inhibin and activin remains unknown for mammary epithelial cells. We investigated the role of these hormones in breast apocrine lesions (BAL) using immunohistochemistry to study androgen receptors (AR) and the inhibin/activin alpha and betaA subunits. Forty-two cases of BAL were evaluated, including 22 cases of fibrocystic disease (FCD) showing prominent apocrine changes, 10 intraductal papillomas with extensive apocrine metaplasia, 5 cases of apocrine carcinoma in situ (CIS), and 5 cases of apocrine carcinoma. Fifty non-apocrine lesions were included as controls: 20 cases of FCD, 5 cases of DCIS, and 25 cases of invasive ductal carcinoma. AR was more frequently expressed in BAL than in non-apocrine lesions (p=0.001). AR expression was not related to tumor progression. AR showed a significant positive correlation with betaA subunits (r=0.832, p<0.001), and an inverse correlation with alpha subunits (r=-0.233). The alpha and betaA subunits demonstrated a significant inverse correlation with each other (r=-0.271, p=0.0048). As the expression of the alpha and betaA subunits reflects inhibin and activin A, respectively, AR and activin A may be implicated in apocrine morphogenesis, but not in tumor progression.

Molecular pathology of breast apocrine carcinomas: A protein expression signature specific for benign apocrine metaplasia

Breast cancer is a heterogeneous disease that encompasses a wide range of histopathological types including: invasive ductal carcinoma, lobular carcinoma, medullary carcinoma, mucinous carcinoma, tubular carcinoma, and apocrine carcinoma among others. Pure apocrine carcinomas represent about 0.5% of all invasive breast cancers according to the Danish Breast Cancer Cooperative Group Registry, and despite the fact that they are morphologically distinct from other breast lesions, there are at present no standard molecular criteria available for their diagnosis. In addition, the relationship between benign apocrine changes and breast carcinoma is unclear and has been a matter of discussion for many years. Recent proteome expression profiling studies of breast apocrine macrocysts, normal breast tissue, and breast tumours have identified specific apocrine biomarkers [15-hydroxyprostaglandin dehydrogenase (15-PGDH) and hydroxymethylglutaryl coenzyme A reductase (HMG-CoA reductase)] present in early and advanced apocrine lesions. These biomarkers in combination with proteins found to be characteristically upregulated in pure apocrine carcinomas (psoriasin, S100A9, and p53) provide a protein expression signature distinctive for benign apocrine metaplasias and apocrine cystic lesions. These studies have also presented compelling evidence for a direct link, through the expression of the prostaglandin degrading enzyme 15-PGDH, between early apocrine lesions and pure apocrine carcinomas. Moreover, specific antibodies against the components of the expression signature have identified precursor lesions in the linear histological progression to apocrine carcinoma. Finally, the identification of proteins that characterize the early stages of mammary apocrine differentiation such as 15-PGDH, HMG-CoA reductase, and cyclooxygenase 2 (COX-2) has opened a window of opportunity for pharmacological intervention, not only in a therapeutic manner but also in a chemopreventive setting. Here we review published and recent results in the context of the current state of research on breast apocrine cancer.

Apocrine cysts of the breast: biomarkers, origin, enlargement, and relation with cancer phenotype

Up to one-third of women aged 30-50 years have cysts in their breasts and are presumed to be at increased risk of developing breast cancer. Here we present an extensive proteomic and immunohistochemistry (IHC) study of breast apocrine cystic lesions aimed at generating specific biomarkers and elucidating the relationship, if existent, of apocrine cysts with cancer phenotype. To this end we compared the expression profiles of apocrine macrocysts obtained from mastectomies from high risk cancer patients with those of cancerous and non-malignant mammary tissue biopsies collected from the same patients. We identified two biomarkers, 15-hydroxyprostaglandin dehydrogenase and 3-hydroxymethylglutaryl-CoA reductase, that were expressed specifically by apocrine type I cysts as well as by apocrine metaplastic cells in type II microcysts, terminal ducts, and intraductal papillary lesions. No expression of these markers was observed in non-malignant terminal ductal lobular units, type II flat cysts, stroma cells, or fat tissue as judged by IHC analysis of matched non-malignant tissue samples collected from 93 high risk patients enrolled in our cancer program. IHC analysis of the corresponding 93 primary tumors indicated that most apocrine changes have little intrinsic malignant potential, although some may progress to invasive apocrine cancer. None of the apocrine lesions examined, however, seemed to be a precursor of invasive ductal carcinomas, which accounted for 81% of the tumors analyzed. Our studies also provided some insight into the origin, development, and enlargement of apocrine cysts in mammary tissue. The successful identification of differentially expressed proteins that characterize specific steps in the progression from early benign lesions to apocrine cancer opens a window of opportunity for designing and testing new approaches for pharmacological intervention, not only in a therapeutic setting but also for chemoprevention, to inhibit cyst development as both 15-hydroxyprostaglandin dehydrogenase and 3-hydroxymethylglutaryl-CoA reductase are currently being targeted for chemoprevention strategies in various malignancies.

Expression of GCDFP-15 and AR decreases in larger or node-positive apocrine carcinomas of the breast

AIMS

Apocrine carcinoma of the breast is typically, though not always, positive for gross cystic disease fluid protein-15 (GCDFP-15). In order to clarify the clinical significance of GCDFP-15 in apocrine carcinomas, GCDFP-15 expression was examined in apocrine carcinomas of different stages and compared with clinicopathological factors. Apocrine lesions reportedly exhibit an unusual immunohistochemical status, expressing androgen receptors (AR) instead of oestrogen receptors (ER), progesterone receptors (PR), or bcl-2. Their expression was also examined.

METHODS AND RESULTS

Fifty-two apocrine carcinomas were examined immunohistochemically. Thirty-nine (75%) and 29 (56%) were positive for GCDFP-15 and AR, respectively. GCDFP-15 positivity was significantly lower in infiltrating carcinomas than intraductal carcinomas (P = 0.0111). In infiltrating carcinomas, GCDFP-15 positivity was significantly low in tumours > or = 15 mm (P = 0.0005) and node-positive tumours (P = 0.0004). Similar phenomena were observed for AR. Rare cases were positive for ER (3.8%), PR (5.8%), and bcl-2 (1.9%).

CONCLUSIONS

GCDFP-15 positivity is transient and should not be considered a definitive marker of apocrine carcinomas. Cases which have apocrine features but lack GCDFP-15 expression should rather be considered as advanced apocrine carcinomas. ER/PR/bcl-2 negativity will sometimes be helpful to confirm the diagnosis of apocrine carcinoma, because it is more consistent than GCDFP-15/AR positivity.

Clinicopathological feature and long-term prognosis of apocrine carcinoma of the breast in Japanese women

Because of the rarity of apocrine carcinoma and lack of standardized criteria for the diagnosis, the definitive conclusions of clinicopathologic features and the prognosis has not been determined. We retrospectively examined data on 2091 curatively treated Japanese patients with primary breast carcinoma. Among them, 33 (1.6%) who had been diagnosed of apocrine carcinoma were reviewed. Compared with non-apocrine carcinoma, apocrine carcinoma was characterized by less positive rates of ER and PR, and by frequent rates of unilateral multicentric breast carcinoma with significant difference. The clinicopathological factors influencing 12-year survival rate were lymph node metastasis, lymphatic involvement and vascular involvement. There was no difference in survival rates at 10 years after operation between apocrine carcinoma and non-apocrine carcinoma. Our result shows unique hormone response and unilateral multicentricity are only typical clinicopathological features of apocrine carcinoma.

c-erbB-2 expression and nuclear pleomorphism in canine mammary tumors

The objective of the present investigation was to study the expression of c-erbB-2 and MIB-1 and try to associate them with morphological features of the cell such as nuclear pleomorphism, mitotic count and histological grade in a series of 70 canine mammary gland tumors, 22 of them benign and 48 malignant. Tumors were collected at the Veterinary Hospital of UFMG (Brazil) and the Veterinary Faculty of Porto University (Portugal). c-erbB-2 expression was determined according to the guidelines provided by the manufacturer of the HercepTest system and nuclear pleomorphism, mitotic count and histological grade according the Elston and Ellis grading system. The HercepTest is the FDA-approved in vitro diagnostic test marketed by Dako. It is a semi-quantitative immunohistochemical assay used to determine overexpression of HER2 protein (human epidermal growth factor receptor) in breast cancer tissue. MIB-1 expression was also evaluated in 28 malignant tumors. Seventeen (35.4%) of the malignant tumors were positive for c-erbB-2 expression, which was positively associated with nuclear pleomorphism (P < 0.0001), histological grade (P = 0.0017) and mitotic count (P < 0.05). Nuclear pleomorphism also showed a positive association with MIB-1 index (P < 0.0001). These results suggest that some of the biological and morphological characteristics of the tumor are associated in canine mammary gland tumors, as also reported for human breast cancer. It was also possible to show that the immunoexpression of c-erbB-2 can be a factor in mammary carcinogenesis. This fact opens the possibility of using anti-c-erbB-2 antibodies in the treatment of canine mammary tumors.

The spectrum of apocrine lesions of the breast

Apocrine change is seen in a wide spectrum of breast lesions, ranging from microscopic cysts to invasive carcinoma. This article reviews the range of apocrine lesions and discusses the clinical significance of these lesions. Although apocrine change in many cases does not present any diagnostic difficulty, apocrine proliferations demonstrating cytologic atypia can be particularly challenging. The histologic criteria that have been proposed to foster reproducibility in categorizing such lesions are reviewed. This review attempts to clarify the terminology that has been applied to a range of benign lesions, including sclerosing adenosis and complex sclerosing lesions, containing foci of apocrine change. Malignant apocrine lesions, including both in situ and invasive carcinoma, are also discussed.

The histologic spectrum of apocrine lesions of the breast

New data on apocrine carcinoma of the breast, especially on its unusual pathogenesis, are the facts that justify this study. The aim of this study was to describe the morphological features in both benign apocrine lesions and invasive apocrine carcinomas of the breast. The following apocrine lesions were pointed out: cysts, metaplasia, adenosis, adenoma, borderline malignant lesion, intraductal carcinoma and invasive apocrine carcinoma. Surgical specimens of breast benign and malignant lesions were fixed in formalin, embedded in paraffin blocks and the slides were stained with HE, PAS and immuno- histochemical ABC complex methods, using primary antibodies against: p53, Ki-67, androgen receptor, and GCDFP-15. The criteria of apocrine lesions, as well as classification of apocrine carcinoma were pointed out also. In the discussion we cited literature data about incidence of apocrine lesions in the breast, immunohistochemical, ultrastructural and molecular characteristics of apocrine lesions focusing on differential diagnostic problems between apocrine and nonapocrine lesions, and benign versus malignant apocrine lesion. The authors have suggested that apocrine carcinoma represents unusual type of the breast carcinoma and which may origin from the following precancerous lesions: apocrine hyperplasia, apocrine adenosis, atypical apocrine adenosis and adenoma. Immunohistochemical markers for apocrine differentiation are: GCDFP-15 and androgen receptors. Ki-67 and p53 may be good markers for differentiation between benign and malignant breast apocrine lesions. Positively staining for androgen receptors, not only in apocrine carcinoma of the breast, but also in benign lesions, has led some authors to postulate a possible role of androgens in the stimulation of breast epithelium and the development of apocrine cells and apocrine carcinomas. However, in this stage the clinical significance remains uncertain and follow-up studies will be required to evaluate this issue.

Androgen receptors frequently are expressed in breast carcinomas: potential relevance to new therapeutic strategies

BACKGROUND

Several studies have demonstrated the biologic and therapeutic significance of estrogen and progesterone receptors (ER and PR) in breast carcinomas. The aim of the current study was to examine the presence of androgen receptors (AR) in breast carcinomas.

METHODS

Two hundred cases of breast carcinoma, consisting of 145 invasive and 55 noninvasive (ductal carcinoma in situ [DCIS]) lesions, were examined using a monoclonal antibody against AR on formalin-fixed, paraffin-embedded archival material. The results were analyzed for correlations with immunohistochemically determined ER, PR, and HER-2/neu expression.

RESULTS

Eighty-seven of the 145 cases (60%) of invasive carcinoma and 45 of the 55 cases (82%) of DCIS were AR-positive according to internationally standardized guidelines. The vast majority of Grade 1 carcinomas were positive for AR (90% of invasive Grade 1 carcinomas and 95% of Grade 1 DCIS), whereas in Grade 3 invasive carcinomas and DCIS, positive immunoreactions for AR were observed in 46% and 76% of cases, respectively. Among the cases of Grade 3 carcinoma, 33 invasive carcinomas (39%) and 17 DCIS lesions (68%) were ER-negative but AR-positive. Among Grade 1 carcinomas (invasive and DCIS), not a single case was positive for HER-2/neu, but most cases were intensely positive for AR. In contrast, many invasive Grade 3 carcinomas exhibited agreement between AR status and HER-2/neu status (AR-positive and HER-2/neu-positive, 30.5%; AR-negative and HER-2/neu-negative, 42.5%).

CONCLUSIONS

Androgen receptors are commonly expressed in DCIS and in invasive breast carcinoma. A significant number of poorly differentiated carcinomas are ER-negative and PR-negative but AR-positive. Immunohistochemical examination of AR would be desirable because it would provide additional information about steroid receptors in breast carcinomas.

Immunohistochemical evaluation of vasopressin expression in breast fibrocystic disease and ductal carcinoma in situ (DCIS)

We previously found that expression of the vasopressin gene is a common feature of human breast cancer. In the present study we first examined 21 different cases of benign fibrocystic breast disease for vasopressin expression using immunohistochemistry and antibodies directed against vasopressin (anti-VP) and against vasopressin-associated glycopeptide (anti-VAG). All cases examined were negative for vasopressin gene expression using these antibodies. Alternatively, we examined 16 cases of breast ductal carcinoma in situ (DCIS) using the second of these antibodies (anti-VAG), and all of these cases were positive for vasopressin gene expression. Our results suggest that products of vasopressin gene expression are not markers of cellular proliferation in the breast, and might rather represent an early part of the carcinogenic process in this tissue.