C-myc oncoprotein expression and gene amplification in apocrine metaplasia and apocrine change within sclerosing adenosis of the breast

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.

Immunohistochemistry as a Genetic Surrogate in Dermatopathology: Pearls and Pitfalls

Immunohistochemistry (IHC) is routinely performed in most laboratories, and other than purchase of commercially available antibodies, requires no additional equipment or reagents. As such, IHC is an accessible and relatively inexpensive test and one that can be performed quite quickly. This is in sharp contrast to genomic or mutational testing methodologies that are routinely "send out" tests as they require specialized equipment and reagents as well as individuals with expertise in the performance of the tests and analysis of the results, resulting in a prolonged turn-round-time and enhanced associated costs. However, many open questions remain in a rapidly changing therapeutic and scientific landscape with most obvious one being what exactly is the utility of "good old fashioned" IHC in the age of targeted therapy? For molecular applications, is a negative immunohistochemical result enough as a stand-alone diagnostic or predictive product? Is a positive immunohistochemical result perhaps more suitable for a role in screening for molecular alterations rather than a definitive testing modality? This review is an attempt to answer those very questions. We elucidate the broad range of entities in which IHC is currently used as a molecular surrogate and underscore pearls and pitfalls associated with each. Special attention is given to entities for which targeted therapies are currently available and to entities in which molecular data is of clinical utility as a prognosticator.

Cyclin D-1 protein over-expression is not associated with gene amplification in benign and atypical apocrine lesions of the breast

Cyclin D-1 protein over-expression and/or gene amplification have been shown to be frequent events in subsets of breast carcinomas. Cyclin D-1 is generally considered as a weak oncogene, and its over-expression has been shown to occur in occasional benign breast lesions. In a previous series, we have shown that cyclin D-1 was over-expressed in subsets of apocrine metaplasia (APM) and apocrine adenosis (AA) of the breast and that such over-expression was mostly associated with a significant increase in the proliferative capacity of these lesions. We examined the mechanisms involved in cyclin D-1 over-expression in apocrine lesions. A total of 41 cases were analysed in this study. The cases were divided into: 18 cases of APM and 23 cases of AA. All cases analysed had been previously analysed by immunohistochemistry, and all showed over-expression of the cyclin D-1 protein. Fluorescence in situ hybridisation (FISH) was performed using a dual cyclin D-1 (spectrum orange)/chromosome 11 centromere (spectrum green) DNA probe. The results showed that none of the cases studied had concomitant gene amplification. These results suggest that other post-transcriptional mechanisms might be responsible for cyclin D-1 protein over-expression in benign apocrine lesions. Further studies are needed to understand the mechanisms involved in abnormal cyclin D-1 expression in these lesions.

Alterations of the cell cycle regulators cyclin D1, cyclin A, p27, p21, p16, and pRb in apocrine metaplasia of the breast

G1/S transition defects have been a proposed requirement for tumor development. Apocrine metaplasia (APM) in the breast has been held as a sign of benignity. Yet, a number of studies have reported the presence of molecular abnormalities in some forms of APM suggesting a possible oncogenic potential for some of these lesions. We currently investigate the role of some of the cell cycle proteins, previously reported to be de-regulated in breast cancer, in an attempt to assess their significance in APM. Using immunohistochemistry, the expression of cyclin D1, cyclin A, p27, p21, p16, pRb and Ki-67 was examined in 93 cases of APM. The cases were divided into nonpapillary (NAPM) (30 cases) and papillary metaplasia (PAPM) (63 cases). PAPM was further subdivided into simple papillary (SPAPM) (29 cases), complex papillary (28 cases) and highly complex papillary (six cases). For statistical analysis, the last two groups were merged together (CPAPM). The results showed that increased histological complexity was associated with significant increase of proliferative capacity and alterations of the cell cycle control. The median Ki-67 index was 1.5% in SPAPM and 4.8% in the CPAPM. Also, alterations of the cell cycle regulators were significantly higher in the CPAPM than in the SPAPM. NAPM was generally similar to normal breast epithelium. Apocrine cells were negative for p16 while pRb was expressed in all cases. These findings suggest that in complex forms of APM, there is a considerable degree of cellular unrest. This may contribute to increased susceptibility to carcinogenesis.

Cell cycle alterations and their relationship to proliferation in apocrine adenosis of the breast

AIMS

Apocrine adenosis (AA) is generally considered a benign disease of the breast. However, recent studies have suggested a precancerous potential for some of these lesions. The aim was to investigate the status of cell cycle proteins previously reported to be deregulated in breast cancer to identify their possible role in AA.

METHODS AND RESULTS

The cases were categorized into AA without atypia (NAA) and atypical AA (AAA). Using immunohistochemistry, the expression of cyclin D1, cyclin A, p27, p21, p16, pRb and Ki67 was determined in 29 NAA and 16 AAA cases. Cyclin D1, p21 and cyclin A were overexpressed in 58.6%, 51.7% and 31.8% of the NAA cases, respectively, whereas 81.3%, 62.5% and 41.7% of the AAA cases showed overexpression of cyclin D1, p21 and cyclin A, respectively. All cases were negative for p16, whereas pRb was expressed in all cases. Furthermore, proliferation in AA (4.5%) was significantly higher than that of normal breast epithelium (1%). There was no statistical significance in the degree of proliferation between the NAA (3.7%) and AAA (4.8%) groups.

CONCLUSIONS

The study indicates that NAA and AAA are biologically similar. A subset of AA defined by increased proliferation and significant cell cycle alterations may be susceptible to oncogenesis.

Ductal adenoma of the breast: immunohistochemistry of two cases

The author reports herein two cases of ductal adenoma of the breast with an emphasis on immunohistochemistry. Both cases (patient 1, 58-year-old woman; patient 2, 78-year-old woman) were clinically suspected as carcinoma, and core biopsies were 'indeterminate' or 'suspicious for malignancy'. Excisional biopsy and wide excision were performed. Histologically, both cases were ductal adenomas composed of ductal epithelial cells and myoepithelial cells. Patient 1 had extensive apocrine metaplasia. Immunohistochemically, myoepithelial cells were noted in both cases; cytokeratin (CK) 14 and p63 were the most reliable myoepithelial markers, followed by CD10, alpha-smooth muscle actin and S100 protein. CK profile was as follows: positive expression of CK5/6, CK18, CK19, and high-molecular-weight CK, and negative expression of CK20. This CK profile was the same as that of non-tumorous ducts, suggesting that the CK profile does not alter in tumorigenesis. The tumor cells expressed p53 protein (case 1, positive cell percentage 5%; case 2, 7%), c-erbB2 (HER2/neu, 76%, 64%), CEA (5%, 0%), estrogen receptor (33%, 84%), but were negative for progesterone receptor. Ki-67 labeling was 5% and 3%, respectively. MUC apomucin expression was as follows: MUC1, 92%, 100%; MUC2, 0%, 0%; MUC5AC, 0%, 0%; and MUC6, 5%, 0%. Non-tumorous ducts expressed MUC1, but were negative for MUC2, MUC5AC and MUC6.

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.

Characterization of breast precancerous lesions and myoepithelial hyperplasia in sclerosing adenosis with apocrine metaplasia

The identification as well as the molecular characterization of breast precancerous lesions in terms of increased risk of progression and/or recurrence is becoming a critical issue today as improved non-surgical procedures are detecting cancer at an earlier stage. The strategy we have been pursuing to identify early apocrine breast lesions is based on the postulate that invasive apocrine carcinomas evolve from epithelial cells in terminal duct lobular units (TDLUs) in a stepwise manner that involves apocrine metaplasia of normal breast epithelia, hyperplasia, atypia, and apocrine carcinoma in situ. First, we identify specific protein biomarkers for benign apocrine metaplasia and thereafter we search for biomarkers that are highly overexpressed by pure invasive apocrine carcinomas. Here we present studies in which we have used antibodies against components of a benign apocrine signature that includes 15-prostaglandin dehydrogenase (15-PGDH), a protein that is expressed by all benign apocrine lesions, and markers that are highly overexpressed by pure invasive apocrine carcinomas such as MRP14 (S100A9), psoriasin (S100A7), and p53 to identify precancerous lesions in sclerosing adenosis (SA) with apocrine metaplasia. The latter is a benign proliferative lesion of the breast that exhibits an increase in the size of the TDLUs and characterized by retained two-cell lining, and myoepithelial (ME) and stromal hyperplasia. SA with apocrine metaplasia, i.e. apocrine adenosis (AA), presents with a higher degree of atypical apocrine hyperplasia, and these lesions are believed to be precursors of apocrine carcinoma, in situ and invasive. Analysis of 24 selected SA samples with apocrine metaplasia revealed non-obligate putative apocrine precancerous lesions that displayed some, or in same cases all the three markers associated with pure invasive apocrine carcinomas. These studies also revealed p53 positive, non-apocrine putative precancerous lesions as well as novel phenotypes for ME and some luminal cells characterized by the expression of cytokeratin 15.

Evaluation of c-MYC status in primary acquired cholesteatoma by using fluorescence in situ hybridization technique

OBJECTIVE

The object of study was to investigate the status of c-MYC oncogene in primary acquired cholesteatoma.

STUDY DESIGN

Descriptive study.

METHODS

Cholesteatoma samples were obtained from 15 patients with primary acquired cholesteatoma during surgical operation. Fluorescence in situ hybridization with a mixed DNA probe, which is specific for c-MYC located on 8q24 and chromosome 8 specific-alpha-satellite DNA probe (dual color), was used on the interphase nuclei.

RESULTS

Copy number of c-MYC oncogene and aneuploidy of chromosome 8 were 21.2% +/- 14.4% and 21.7% +/- 14.8%, respectively. There was no significant difference between copy number of c-MYC and frequency of chromosome 8 aneuploidy (p > 0.05). Ten of 15 cases showed different percentage of c-MYC and chromosome 8 aneuploidy, whereas 5 (33.3%) of 15 cases showed a normal distribution of c-MYC and chromosome 8 signals.

CONCLUSION

The copy number of c-MYC in 10 of 15 cases was found to be high as observed for chromosome 8 aneuploidy in primary acquired cholesteatoma. These findings suggest that the ability of hyperproliferation of primary acquired cholesteatoma might have been related to c-MYC copy number by deregulating c-MYC expression.

Early breast cancer

Breast cancer remains a common disease throughout the world. Here we review new knowledge about early breast cancer obtained during the past 5 years. The prognosis of early breast cancer is generally favorable. Especially, ductal carcinoma in situ has been regarded as a non-life-threatening disease. Therefore, early diagnosis and early onset of the treatment has been important. Early age at menarche, late age at first birth, and late age at menopause are related to breast cancer risk. Examination by mammography and ultrasonography is still the most effective means of detection for premenopausal and postmenopausal women, respectively. Additionally, there have been important advances in MRI, sentinel lymph node biopsy, breast-conserving surgery, partial breast irradiation, neoadjuvant systemic therapy, and adjuvant systemic therapy. Another approach to keeping the disease under control is the elucidation of breast cancer's molecular biological features. Assessment of potential molecular targets can lead to early diagnosis and molecular targeted treatment.

Combined multicolor-FISH and immunostaining

The combination of multicolor-FISH and immunostaining produces a powerful visual method to analyze in situ DNA-protein interactions and dynamics. Representing one of the major technical improvements of FISH technology, this method has been used extensively in the field of chromosome and genome research, as well as in clinical studies, and serves as an important tool to bridge molecular analysis and cytological description. In this short review, the development and significance of this method will be briefly summarized using a limited number of examples to illustrate the large body of literature. In addition to descriptions of technical considerations, future applications and perspectives have also been discussed focusing specifically on the areas of genome organization, gene expression and medical research. We anticipate that this versatile method will play an important role in the study of the structure and function of the dynamic genome and for the development of potential applications for medical research.

The MYC oncogene in breast cancer progression: from benign epithelium to invasive carcinoma

One hypothesis for breast cancer development suggests that breast carcinogenesis involves a progression of events leading from benign epithelium to hyperplasia (with or without atypia) to carcinoma in situ and then invasive carcinoma. The MYC gene (alias c-Myc) is a transcriptional regulator whose expression is strongly associated with cell proliferation and cell differentiation. The present study is a descriptive analysis of MYC status throughout the hypothesized stages of invasive ductal carcinoma progression. A tissue microarray (TMA) was constructed including representative selected areas (normal cells, hyperplasia, in situ carcinoma, and invasive carcinoma) from each of 15 patients. Fluorescence in situ hybridization (FISH) with the LSI c-MYC/CEN8/IgH probe was performed. Two cases displayed MYC amplification (13%), showing this amplification only in the invasive carcinoma zones selected. Five cases displayed polysomy of chromosome 8 (33%), detected only in ductal in situ and invasive zones selected. Benign lesions and normal adjacent cells were classified as normal. None of the hyperplasia specimens and normal specimens analyzed showed any alterations in MYC status or any aneusomies of chromosome 8. The presence of MYC amplification only in invasive cells suggests that the finding of MYC amplification could reflect an advanced 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.