Feasibility of abbreviated magnetic resonance imaging (AB-MRI) screening in women with a personal history (PH) of breast cancer

PURPOSE

To investigate the feasibility of abbreviated magnetic resonance imaging (AB-MRI) in women with a personal history (PH) of breast cancer as a screening tool.

MATERIALS AND METHODS

We retrospectively reviewed 1880 screening AB-MRIs in 763 women with a PH of breast cancer (median age, 55 years; range, 23-89 years) between October 2015 and October 2016. The total acquisition times of AB-MRI were 8.3 min and 2.8 min with and without T2-weighted imaging, respectively. The tissue diagnosis or one-year follow-up status was used as the reference standard. The characteristics of tumor recurrences detected on AB-MRI screenings were analyzed. The cancer detection rates (CDRs) and additional CDRs for the 1st round and overall rounds of AB-MRI screening were calculated. The recall rate, sensitivity, specificity, positive predictive values for recall (PPV1) and biopsy (PPV3) for the 1st round of AB-MRI screening were calculated. The diagnostic performance of the combination of mammography and ultrasonography was compared with that of AB-MRI by receiver operating characteristic (ROC) curve analysis.

RESULTS

Fifteen of a total of 21 recurrences were detected on the 1st round of AB-MRI screening: 93.3% were node-negative T1 tumors (median tumor size, 1.02 cm; range, 0.1-2 cm) or Tis; 66.7% were high-grade tumors; 8 of these 15 were mammographically and ultrasonographically occult. The CDR and additional CDR for the 1st round of AB-MRI screening were 0.019 and 0.010 per woman, respectively. The sensitivity, specificity, recall rate, PPV1 and PPV3 for the 1st round of AB-MRI screening were 100%, 96.0%, 14.3%, 13.8% and 58.3%, respectively. For detecting secondary cancer, AB-MRI showed a higher sensitivity and PPV than the combination of mammography and ultrasonography (95.2%, 57.1% vs 47.6%, 38.5%). The area under the ROC curve was higher for AB-MRI (0.966; 95% CI: 0.951-0.978) than the combination of mammography and ultrasonography (0.727; 95% CI: 0.694-0.759) (P<0.0001).

CONCLUSION

AB-MRI improved cancer detection with a high specificity, sensitivity and PPV in women with a PH of breast cancer. AB-MRI could be a useful screening tool for detecting secondary cancer considering its high diagnostic performance and short examination time.

Structural Studies of Epithelial Mesenchymal Transition Breast Tissues

At the supramolecular level, the proliferation of invasive ductal carcinoma through breast tissue is beyond the range of standard histopathology identification. Using synchrotron small angle x-ray scattering (SAXS) techniques, determining nanometer scale structural changes in breast tissue has been demonstrated to allow discrimination between different tissue types. From a total of 22 patients undergoing symptomatic investigations, different category breast tissue samples were obtained in use of surgically removed tissue, including non-lesional, benign and malignant tumour. Structural components of the tissues were examined at momentum transfer values between q = 0.2 nm-1 and 1.5 nm-1. From the SAXS patterns, axial d-spacing and diffuse scattering intensity were observed to provide the greatest discrimination between the various tissue types, specifically in regard to the epithelial mesenchymal transition (EMT) structural component in malignant tissue. In non-lesional tissue the axial period of collagen is within the range 63.6-63.7 nm (formalin fixed paraffin embedded (FFPE) dewaxed) and 63.4 (formalin fixed), being 0.9 nm smaller than in EMT cancer-invaded regions. The overall intensity of scattering from cancerous regions is a degree of magnitude greater in cancer-invaded regions. Present work has found that the d-spacing of the EMT positive breast cancer tissue (FFPE (dewaxed)) is within the range 64.5-64.7 nm corresponding to the 9th and 10th order peaks. Of particular note in regard to formalin fixation of samples is that no alteration is observed to occur in the relative differences in collagen d-spacing between non-lesional and malignant tissues. This is a matter of great importance given that preserved-sample and also retrospective study of samples is greatly facilitated by formalin fixation. Present results indicate that as aids in tissue diagnosis SAXS is capable of distinguishing areas of invasion by disease as well as delivering further information at the supramolecular level.

Core needle biopsy of benign, borderline and in-situ problematic lesions of the breast: Diagnosis, differential diagnosis and immunohistochemistry

Core needle biopsy (CNB) is the most common sampling technique for the histologic evaluation of breast abnormalities. Diagnosing benign proliferative, borderline and some in-situ lesions in CNB is challenging and subject to a significant degree of interobserver variability. In addition, due to the inherent limitations of CNB, "upgrading" to a more significant pathology at excision is an important consideration for some lesions. Pathologists carry a major responsibility in patient diagnosis, risk stratification and management. Familiarity with the histologic features and the clinical significance of these common and problematic lesions encountered in CNB is necessary for adequate treatment and patient follow-up. This review will focus on benign, atypical and in-situ epithelial proliferations, papillary lesions, radial sclerosing lesions, adenosis and cellular fibroepithelial lesions. Highlights of histologic features, useful strategies for accurate diagnosis, basic immunohistochemistry and management will be presented.

Intracystic Papillary Carcinoma of the Male Breast. A Case Report: (Histochemical, immunohistochemical and ultrastructural study)

We report a case of intracystic papillary carcinoma of the male breast in a 70-year-old male Caucasian. Grossly, the tumor was a cystic lesion measuring 6 cm in diameter. It contained hemorrhagic fluid and a mural nodule with filiform projections. PAS stain with and without digestion revealed small clumps of diastase-resistent material in the cytoplasm of the neoplastic cells. Grimelius stain was positive. Immunoperoxidase stains were negative for neuron-specific enolase, S100 protein, cromogranin and synaptophysin and were positive for carcinoembryonic antigen and epithelial membrane antigen. On ultrastructural examination the neoplastic cells showed membrane-bound, dense-core secretory granules. We believe that this neoplasm, despite negative neuroendocrine markers, is a variant of mammary adenocarcinoma with endocrine differentiation, partly because of the positive Grimelius stain and partly because of the presence of electron-dense granules, which according to some authors represent lactational differentiation.

Independent Submacroscopic Foci of Infiltrating Carcinoma in Breasts Removed for Clinical Cancer

The aim of our study was the detection and the characterization of submacroscopic foci of infiltrating carcinoma in the human female mammary glandular tree collateral to clinical cancer. Accordingly, we analyzed 100 breasts surgically removed by radical mastectomy. Five thin slices per case were analyzed under a dissecting microscope by subgross method of observation. Submacroscopic foci of invasive cancer, well separated and apparently independent of the primary tumor, were found in 19 % of the cases and were confirmed by histologic examination. Foci of submacroscopic cancer were either single (79 %) or multiple (21 %), and were located in slices including or not the main tumor mass (31 % and 69 % of cases, respectively). Their size ranged from 1 to 4 mm. Four histologic types were represented: 1) invasive ductal NOS with productive fibrosis, scirrhous type (36 % of cases); 2) invasive ductal NOS without productive fibrosis, simplex type (32 % of cases); 3) invasive ductal with tubular component (16 % of cases); 4) medullary (16 % of cases). Concordance between histology of clinical and submacroscopic cancers was assessed in 42 % of cases. A significant association of the tubular type (invasive ductal carcinoma with a consistent tubular component) of primary tumor was demonstrated (P < 0.05), as well as with the presence of ductal and lobular proliferative changes in the collateral glandular tree (intraductal papillomas, P < 0.01; atypical lobules, P < 0.02). No relationship was found between submacroscopic foci of infiltrating carcinoma and neoplastic familiarity, patients’ age by decades, axillary lymph node metastases, size of clinical tumor or profile of the collateral mammary glandular tree. These data support the hypothesis of a multicentric origin of human breast cancer and suggest a systemic nature of the neoplastic mammary disease. Prognostic and therapeutic implications of this concept are discussed.

Benign Smooth Muscle Cell Metaplasia in Breast

Three different benign breast lesions showing smooth muscle cells in the stroma are reported. Benign smooth muscle cells are rarely found in the breast, and it is likely that they originate from metaplastic changes of the stroma itself.

Correlative imaging reveals physiochemical heterogeneity of microcalcifications in human breast carcinomas

Microcalcifications (MCs) are routinely used to detect breast cancer in mammography. Little is known, however, about their materials properties and associated organic matrix, or their correlation to breast cancer prognosis. We combine histopathology, Raman microscopy, and electron microscopy to image MCs within snap-frozen human breast tissue and generate micron-scale resolution correlative maps of crystalline phase, trace metals, particle morphology, and organic matrix chemical signatures within high grade ductal carcinoma in situ (DCIS) and invasive cancer. We reveal the heterogeneity of mineral-matrix pairings, including punctate apatitic particles (<2 µm) with associated trace elements (e.g., F, Na, and unexpectedly Al) distributed within the necrotic cores of DCIS, and both apatite and spheroidal whitlockite particles in invasive cancer within a matrix containing spectroscopic signatures of collagen, non-collagen proteins, cholesterol, carotenoids, and DNA. Among the three DCIS samples, we identify key similarities in MC morphology and distribution, supporting a dystrophic mineralization pathway. This multimodal methodology lays the groundwork for establishing MC heterogeneity in the context of breast cancer biology, and could dramatically improve current prognostic models.

Immunocytochemical localization of the ectoenzyme aminopeptidase N in the human breast

The ectoenzyme aminopeptidase N (APN) was localized in the normal human breast at both the light microscopic and the ultrastructural level. APN was expressed on intralobular and interlobular fibroblasts and on the apical surface of some luminal epithelial cells. This enzyme was not detected on either myoepithelial cells and their associated basement membrane or capillary endothelium. Furthermore, the staining pattern was maintained in benign and malignant breast disease. APN belongs to a family of enzymes that hydrolyze peptides in the extracellular space. As with other ectoenzymes present in the breast, APN expression is restricted to specific cell types. This pattern of expression may indicate a role for these enzymes in the biology of the normal breast.

Molecular analysis of BRCA1 and BRCA2 genes by next generation sequencing and ultrastructural aspects of breast tumor tissue

In this paper, we focus our interest on the dynamics alterations of the tumor-stroma interface at the ultrastructural level and to detect BRCA1 and BRCA2 mutations using next generation sequencing (NGS) of breast tumor tissue. Electron microscopic investigation revealed some peculiar infrastructural alterations of the tumor cells per se as well as of the tumor-stroma interface: invadopodia, shedding microvesicles, altered morphology and reduced number of telocytes, different abnormalities of the microvasculature. Tumor suppressor genes BRCA1 and BRCA2 are the genes with most hereditary predisposition to breast and ovarian cancer. An early identification of mutation within these genes is essential for determining classification and therapeutic approach to patients. Genetic tests used to determine mutations in BRCA1 and BRCA2 genes are laborious analysis methods which include, among others, NGS. We analyzed a total of eight samples, in which genomic DNA was amplified using Ion AmpliSeq panel BRCA1 and BRCA2. DNA libraries were created, amplified and sequenced with Ion Torrent Personal Genome Machine. The bio-information data obtained allow us to detect all known pathogenic mutation and uncertain polymorphisms.

Mammographic and sonographic features of triple-negative invasive carcinoma of no special type

The aim of this study was to compare the mammography, ultrasound (US) and histologic features of triple-negative (TN) invasive carcinoma of no special type (NST) to non-TN invasive carcinoma of NST. The second aim was to assess whether the distinct imaging characteristics of TN breast cancer would persist after controlling for the histologic features. A total of 344 invasive carcinomas of NST in 337 patients from January 2007 to February 2008 were included in this study. Two radiologists retrospectively reviewed the mammography and US findings using the American College of Radiology Breast Imaging Reporting and Data System (BI-RADS) lexicon and our institution's criteria. On mammography, TN invasive carcinoma of NST most commonly presented as a mass with round shape and non-spiculated margin. On US, it was more likely to have internal hypoechogenicity, an abrupt boundary and posterior acoustic enhancement. TNBC lacked major suspicious imaging findings such as an irregular shape, spiculated margin and calcification.

Accurate characterization of benign and cancerous breast tissues: aspecific patient studies using piezoresistive microcantilevers

Breast cancer is the largest detected cancer amongst women in the US. In this work, our team reports on the development of piezoresistive microcantilevers (PMCs) to investigate their potential use in the accurate detection and characterization of benign and diseased breast tissues by performing indentations on the micro-scale tissue specimens. The PMCs used in these experiments have been fabricated using laboratory-made silicon-on-insulator (SOI) substrate, which significantly reduces the fabrication costs. The PMCs are 260 μm long, 35 μm wide and 2 μm thick with resistivity of order 1.316×10(-3) Ω cm obtained by using boron diffusion technique. For indenting the tissue, we utilized 8 μm thick cylindrical SU-8 tip. The PMC was calibrated against a known AFM probe. Breast tissue cores from seven different specimens were indented using PMC to identify benign and cancerous tissue cores. Furthermore, field emission scanning electron microscopy (FE-SEM) of benign and cancerous specimens showed marked differences in the tissue morphology, which further validates our observed experimental data with the PMCs. While these patient aspecific feasibility studies clearly demonstrate the ability to discriminate between benign and cancerous breast tissues, further investigation is necessary to perform automated mechano-phenotyping (classification) of breast cancer: from onset to disease progression.

Mammographic density: intersection of science, the law, and clinical practice

High mammographic density is associated with a two- to sixfold increased risk of breast cancer. Mammographic density can be altered by endogenous and exogenous hormonal factors and generally declines with age. Mammographic density is affected by confounding factors such as age, parity, menopausal status, and body mass index (BMI), thus making interpretation of mammographic density challenging. None of the established means of measuring mammographic density are entirely satisfactory because they are time consuming and/or subjective. Although mammographic density has been shown to predict breast cancer risk, the role of mammographic density in precisely assessing a woman's breast cancer risk over her lifetime and evaluating response to risk-reduction strategies cannot be fully realized until we have a better understanding of the biology that links mammographic density to breast cancer risk.

Mammographic density and risk of breast cancer

The radiographic appearance of the breast on mammography varies among women, and reflects variations in breast tissue composition and the different X-ray attenuation characteristics of these tissues. Fat is radiologically lucent and appears dark on a mammogram. Connective and epithelial tissues are radiologically dense and appear light. These variations in appearance are commonly described as the percentage of the breast image that is radiologically dense, or as percent mammographic density (PMD). There is now extensive evidence that PMD is a risk factor for breast cancer, with a 4- to 6-fold gradient in risk between women with 75% or more PMD compared with those with 10% or less. However, the accuracy of risk prediction in individual women is modest. The extent of PMD is associated inversely with greater age, parity, and weight, and is reduced by the menopause and by tamoxifen. PMD is positively associated with greater height, a family history of breast cancer, and is increased by combined hormone therapy. The relative risk associated with density is substantially larger than the relative risk of breast cancer associated with a family history of the disease or any of the menstrual and reproductive risk factors. It is estimated that the risks of breast cancer attributable to density of 50% or more may be 16% for all breast cancers. Although combined hormone therapy and tamoxifen respectively increase a decrease both PMD and breast cancer risk, there is as yet insufficient evidence to use PMD as a surrogate marker for breast cancer.

Micro-immunohistochemistry using a microfluidic probe

A flexible method to extract more high-quality information from tissue sections is critically needed for both drug discovery and clinical pathology. Here, we present micro-immunohistochemistry (μIHC), a method for staining tissue sections at the micrometre scale. Nanolitres of antibody solutions are confined over micrometre-sized areas of tissue sections using a vertical microfluidic probe (vMFP) for their incubation with primary antibodies, the key step in conventional IHC. The vMFP operates several micrometres above the tissue section, can be interactively positioned on it, and even enables the staining of individual cores of tissue microarrays with multiple antigens. μIHC using such a microfluidic probe is preservative of tissue samples and reagents, alleviates antibody cross-reactivity issues, and allows a wide range of staining conditions to be applied on a single tissue section. This method may therefore find broad use in tissue-based diagnostics and in research.

Analysis of light scattering from human breast tissue using a custom dual-optical scanning near-field optical microscope

In this paper we introduce a custom scanning near-field optical microscope (SNOM) that simultaneously collects reflection and transmission near-field images along with topography. This dual-optical SNOM uses a bent probe, which allows for axial reflection imaging, accurate surface scanning, and easy identification of topographic artifacts. Using this novel dual-optical SNOM, we image desiccated and non-desiccated human breast epithelial tissue. By comparing the simultaneous SNOM images, we isolate the effects of tissue morphology and variations in refractive indices on the forward- and back-scattering of light from the tissue. We find that the reduction in back-scattering from tissue, relative to the glass slide, is caused by dense packing of the scattering sites in the cytoplasm (morphology) in the desiccated tissue and a thin-film of water adhering to the glass slide (refractive index) in the non-desiccated tissue sample. Our work demonstrates the potential of our customized dual-optical SNOM system for label-free tissue diagnostics.

Sonographic appearance of a metastasis to the breast from a cerebellar medulloblastoma

We present the case of a 29-year-old woman with a medulloblastoma of the cerebellum who developed a breast mass during the course of her disease. Core biopsy of the breast lesion revealed a metastatic medulloblastoma. Development of metastasis to the breast from medulloblastoma is very rare and the prognosis for such patients is poor. It is important to distinguish primary breast cancer from metastasis to the breast, because the therapeutic options as well as the prognosis are very different.

Novel gene rearrangements in transformed breast cells identified by high-resolution breakpoint analysis of chromosomal aberrations

Chromosomal copy number alterations and chromosomal rearrangements are frequent mutations in human cancer. Unlike copy number alterations, little is known about the role and occurrence of chromosomal rearrangements in breast cancer. This may be due to the fact that chromosome-based breakpoint analysis is widely restricted to cultured cells. In order to identify gene rearrangements in breast cancer, we studied the chromosomal breakpoints in radiation-transformed epithelial breast cell lines using a high-resolution array-based approach using 1 Mb bacterial artificial chromosome (BAC) arrays. The breakpoints were further narrowed down by fluorescence in situ hybridisation (FISH) with clones from the 32 k BAC library. The analysis of the cell lines B42-11 and B42-16 revealed rearrangements of chromosomes 7, 8, 10 and 12. We identified the genes Has2, Grid1, Ret, Cpm, Tbx3, Tbx5, Tuba1a, Wnt1 and Arf3 within the breakpoint regions. Quantitative RT-PCR showed a deregulated expression of all of these candidate genes except for Tbx5 and Tbx3. This is the first study demonstrating gene rearrangements and their deregulated mRNA expression in radiation-transformed breast cells. Since the gene rearrangements occurred in the transformed and tumourigenic cell lines only, it is likely that these were generated in conjunction with malignant transformation of the epithelial breast cells and therefore might reflect early molecular events in breast carcinogenesis. Initial studies indicate that these gene alterations are also found in sporadic breast cancers.

Breast elastography: a hospital-based preliminary study in China

The performance of ultrasound elastography in the characterization of 170 breast lesions with histologic correlation was evaluated in 150 consecutive patients who were diagnosed as having benign or malignant masses on B mode sonography. Each lesion was classified with ACR's BI-RADS lexicon (benign=2 and 3, malignant 4 and 5) using Ueno elastography classification scores (benign=1-3, malignant=4-5). Of the 170 lesions, 70 were histologically malignant, and 100 were benign. Ultrasound elastography was superior in detecting breast cancer, since the accuracy (95.8%), sensitivity (98.6%), specificity (96.0%), and positive predictive values (94.5%) were higher than those of B mode sonography (90.6%, 91.4%, 90.0% and 86.5% respectively). The sensitivity (98.57%) and false discovery rate (1.1%), when both modalities were jointly used (sonography and /UE) was better then those of sonography and UE singly. However, the specificity (90%) was found similar to sonography. In conclusion, ultrasound elastography is superior to B mode sonography in assessing the nature of breast lesions.

Acoustic imaging of thick biological tissue

Up to now, biomedical imaging with ultrasound for observing a cellular tissue structure has been limited to very thinly sliced tissue at very high ultrasonic frequencies, i.e., 1 GHz. In this paper, we present the results of a systematic study to use a 150 to 200 MHz frequency range for thickly sliced biological tissue. A mechanical scanning reflection acoustic microscope (SAM) was used for obtaining horizontal cross-sectional images (C-scans) showing cellular structures. In the study, sectioned specimens of human breast cancer and tissues from the small intestine were prepared and examined. Some accessories for biomedical application were integrated into our SAM (Sonix HS-1000 and Olympus UH-3), which operated in pulse-wave and tone-burst wave modes, respectively. We found that the frequency 100 to 200 MHz provides optimal balance between resolution and penetration depth for examining the thickly sliced specimens. The images obtained with the lens focused at different depths revealed cellular structures whose morphology was very similar to that seen in the thinly sectioned specimens with optical and scanning acoustic microscopy. The SAM operation in the pulse-echo mode permits the imaging of tissue structure at the surface, and it also opens up the potential for attenuation imaging representing reflection from the substrate behind the thick specimen. We present such images of breast cancer proving the method's applicability to overall tumor detection. SAM with a high-frequency tone-burst ultrasonic wave reveals details of tissue structure, and both methods may serve as additional diagnostic tools in a hospital environment.

Utility of multispectral imaging for nuclear classification of routine clinical histopathology imagery

BACKGROUND

We present an analysis of the utility of multispectral versus standard RGB imagery for routine H&E stained histopathology images, in particular for pixel-level classification of nuclei. Our multispectral imagery has 29 spectral bands, spaced 10 nm within the visual range of 420-700 nm. It has been hypothesized that the additional spectral bands contain further information useful for classification as compared to the 3 standard bands of RGB imagery. We present analyses of our data designed to test this hypothesis.

RESULTS

For classification using all available image bands, we find the best performance (equal tradeoff between detection rate and false alarm rate) is obtained from either the multispectral or our "ccd" RGB imagery, with an overall increase in performance of 0.79% compared to the next best performing image type. For classification using single image bands, the single best multispectral band (in the red portion of the spectrum) gave a performance increase of 0.57%, compared to performance of the single best RGB band (red). Additionally, red bands had the highest coefficients/preference in our classifiers. Principal components analysis of the multispectral imagery indicates only two significant image bands, which is not surprising given the presence of two stains.

CONCLUSION

Our results indicate that multispectral imagery for routine H&E stained histopathology provides minimal additional spectral information for a pixel-level nuclear classification task than would standard RGB imagery.

Secretory phenomena in the non-lactating human mammary gland

The normal non-lactating premenopausal human mammary gland has been shown by immunohistochemistry and transmission electron microscopy to secrete a number of antimicrobial peptides such as beta-defensins, the cathelicidin LL37, lactoferrin and adrenomedullin. In addition, the non-lactating gland elaborates a prominent glycocalyx at the apical membrane of the glandular epithelial cells, parts of which are shed into the lumen of endpieces and ducts. This glycocalyx includes the mucins MUC 1 and MUC 4, a strongly Alcian Blue positive palyanionic component and sulfated material stained with Aldehyde Fuchsin. MUC 1 and the Alcian Blue positive material are considered to play an antimicrobial role, too. Lactalbumin and lipid droplets also occur in the non-lactating gland. At the EM-level secretory phenomena operating by exocytosis and by means of the apocrine mechanism have been observed. Cytoskeletal components presumably play a role in apocrine secretion. Apart from secretion at the cellular apex, secretion at the cellular basis also occurs regularly, which may represent the production of para- or endocrine factors.

Quantitative proteomic analysis of human breast epithelial cells with differential telomere length

Telomeres play important functional roles in cell proliferation, cell cycle regulation, and genetic stability, in which telomere length is critical. In this study, quantitative proteome comparisons for the human breast epithelial cells with short and long telomeres (184-hTERTL vs. 184-hTERTS and 90P-hTERTL vs. 90P-hTERTS), resulting from transfection of the human telomerase reverse transcriptase (hTERT) gene, were performed using cleavable isotope-coded affinity tags. More than 2000 proteins were quantified in each comparative experiment, with approximately 77% of the proteins identified in both analyses. In the cells with long telomeres, significant and consistent alterations were observed in metabolism (amino acid, nucleotide, and lipid metabolism), genetic information transmission (transcription and translation regulation, spliceosome and ribosome complexes), and cell signaling. Interestingly, the DNA excision repair pathway is enhanced, while integrin and its ligands are downregulated in the cells with long telomeres. These results may provide valuable information related to telomere functions.

Membrane Type-1 Matrix Metalloproteinase Confers Aneuploidy and Tumorigenicity on Mammary Epithelial Cells

An elevated expression of membrane type-1 matrix metalloproteinase (MT1-MMP) is closely associated with multiple malignancies. Recently, we discovered that recycled MT1-MMP was trafficked along the tubulin cytoskeleton into the centrosomal compartment and cleaved the integral centrosomal protein pericentrin-2. These events correlated with the induction of chromosome instability and aneuploidy in nonmalignant Madine-Darby canine kidney cells. Accordingly, we hypothesized that MT1-MMP is an oncogene that promotes malignant transformation of normal cells rather than just an enzyme that supports growth of preexisting tumors. To prove our hypothesis, we transfected normal 184B5 human mammary epithelial cells with MT1-MMP (184B5-MT1 cells). MT1-MMP was colocalized with pericentrin in the centrosomal compartment and especially in the midbody of dividing cells. 184B5-MT1 cells acquired the ability to activate MMP-2, to cleave pericentrin, and to invade the Matrigel matrix. 184B5-MT1 cells exhibited aneuploidy, and they were efficient in generating tumors in the orthotopic xenograft model in immunodeficient mice. Because of the absence of tumor angiogenesis and the resulting insufficient blood supply, the tumors then regressed with significant accompanying necrosis. Gene array studies confirmed a significant up-regulation of oncogenes and tumorigenic genes but not the angiogenesis-promoting genes in 184B5-MT1 cells. We believe that our data point to a novel function of MT1-MMP in the initial stages of malignant transformation and to new and hitherto unknown transition mechanism from normalcy to malignancy.

Estimation of subcellular particle size histograms with electron microscopy for prediction of optical scattering in breast tissue

Diffuse near-infrared tomography of tissue reveals scattering changes that originate from the submicroscopic features of the tissue; yet the existing tools to use this information to predict which features contribute to the scattering spectrum are limited by the lack of direct data quantifying the particle sizes. Breast tissue was examined with electron microscopy, and analysis showed that the distributions of particle sizes appear in double exponential functions for most cellular tissues. The average particle size histograms of high-grade cancer, low-grade cancer, fibroglandular tissue, and adipose tissue were examined. The particle histograms were progressively decreasing in magnitude for these tissue types, and the average size of the particles increased, for these four tissues, respectively. Typical particle sizes in the range of 10 to 500 nm for these tissue types, with biexponential fitting, gave two particle distributions: one near 20 to 25 nm for the smaller size and one at 110 to 230 nm for the larger distributions. Mie scatter theory was used to take these particle distributions and calculate scattering spectra. The ability to image reduced scattering coefficient spectra of bulk breast tissues exists, and so this data provides insight into how bulk imaging may be mapped over to predict factors related to the tissue ultrastructure.

Effects of estradiol and medroxyprogesterone acetate on morphology, proliferation and apoptosis of human breast tissue in organ cultures

Background

Human breast tissue undergoes phases of proliferation, differentiation and regression regulated by changes of the levels of circulating sex hormones during the menstrual cycle or aging. Ovarian hormones also likely play a key role in the etiology and biology of breast cancer. Reports concerning the proliferative effects of steroid hormones on the normal epithelium of human breast have been conflicting. Some studies have shown that steroid hormones may predispose breast epithelial cells to malignant changes by stimulating their proliferation, which is known to be regulated tightly by stromal cells.

The aim of this study was to investigate the effects of 17β-estradiol and medroxyprogesterone acetate on proliferation, apoptosis, expression of differentiation markers and steroid hormone receptors in breast epithelium using an in vitro model of freshly isolated human breast tissue, in which a proper interaction of breast epithelium and stroma has been maintained.

Methods

Human breast tissues were obtained from women undergoing surgery for breast tumours. Peritumoral tissues were excised and explants were cultured for 3 weeks in medium supplemented with E₂ or MPA or with E₂+MPA. Endpoints included histopathological, histomorphometric and immunohistochemical assessment of the breast explants.

Results

Culture of breast explants for 14 or 21 days with steroid hormones increased proliferative activity and the thickness of acinar and ductal epithelium. E₂-treatment led to hyperplastic epithelial morphology, MPA to hypersecretory single-layered epithelium and E₂+MPA to multilayered but organised epithelium.

The proliferative response to E₂ in comparison to control (p < 0.001) was more pronounced than to MPA (p < 0.05) or E₂+MPA (p < 0.05) at 7 and 14 days for Ki-67 and PCNA. E₂ treatment also decreased the proportion of apoptotic cells after 7 (p < 0.01) and 14 (p < 0.01) days. In addition, the relative number of ERα, ERβ and PR positive epithelial cells was decreased by all hormonal treatments.

Conclusion

Organ culture system provides a model for studying the direct effects of steroid hormones and their analogues on postmenopausal human breast tissue.

Addition of E₂ or MPA or E₂+MPA to breast explants caused characteristic changes in morphology, stimulated epithelial proliferation, lowered apoptosis ratio and decreased the relative number of epithelial cells expressing ERα, ERβ and PR.

Beneficial effects of soy protein in the initiation and progression against dimethylbenz [a] anthracene-induced breast tumors in female rats

This study was to demonstrate by histological grading whether soy protein protects against dimethylbenz[a]anthracene (DMBA) -induced breast tumors in female rats. At 25 days of age, rats were fed diets containing either casein or soy protein. After 25 days on diets, a single dose of DMBA in sesame oil (80 mg/kg) was administered by gavage. All tumors were detected by palpation. The number of tumors per rat was less in soy group than that in casein group at any time point up to 122 days after DMBA administration. Incidence of tumors was less in soy protein group than that in casein group. Casein group had 20% grade I, 60% grade II, and 20% grade III adenocarcinoma. However, the soy group had 100% grade I adenocarcinoma and no aggressive grade II or grade III tumor. There was a delay in the development of tumor in the soy protein group in comparison to the casein group. Again, unlike casein, the soy group had cessation of angiogenesis at several sites of tumor, and reduced levels of angiogenic markers, VEGF and bFGF. Immunohistochemical analysis of the breast tissues did not show any CD-31 positive stain in soy protein group, whereas some CD-31 positive stain was revealed in casein group, which further suggests that soy protein controls angiogenesis. Furthermore, proliferative index as assessed by Ki-67 staining was less in soy protein group than that in casein group. These findings suggest that the soy protein may protect against the development of a more aggressive breast carcinoma.

Nuclear morphometry in columnar cell lesions of the breast: is it useful?

AIMS

To evaluate the nuclear morphometric features of breast columnar cell lesions (CCLs) observed on mammotome core biopsies, to determine if there are significant measurable differences between those with atypia and those without. Correlation with follow-up open excision specimens was made.

METHODS

Mammotome core biopsies performed on patients that contained CCLs were derived from the departmental case files. Histological material was reviewed and foci of CCLs demarcated for nuclear morphometric assessment, which was accomplished using an imaging system. Nuclear parameters studied were nuclear area and perimeter, circularity factor and feret's diameter. Statistical analysis used the GraphPad Prism software, with p<0.05 indicating significance.

RESULTS

On examination of core biopsies of 40 patients with CCLs, 8 lesions were benign, 4 showed atypical lobular hyperplasia, 8 showed CCLs with nuclear atypia, 19 disclosed atypical ductal hyperplasia (ADH) and 1 showed ductal carcinoma in situ (DCIS). The nuclear area, perimeter and feret's diameter of CCLs with atypia were significantly greater than those without (p = 0.04, 0.03 and 0.019, respectively), whereas no difference was observed in the circularity factor. Follow-up open excision biopsy specimens in 24 patients showed upgrading to DCIS in 40% of cases diagnosed initially with ADH on core biopsy compared with 20% of CCLs with atypia.

CONCLUSIONS

Nuclear morphometry in CCLs confirms nuclear size as the key parameter in the assessment of nuclear atypia. Whether it can be potentially used as an adjunctive tool depends on the establishment of appropriate cut-offs.

Electron microscopic findings for diagnosis of breast lesions

The normal mammary gland can be roughly divided into the large duct close to the nipple and the terminal duct located within the lobulus. Both the large duct and the terminal duct are composed of epithelial cells and myoepithelial cells. The epithelial cells can be divided into light and dark cells using electron density. Heterochromatin is the predominant type of chromatin found in normal mammary glands. The cytoplasm of myoepithelial cells contains a number of fine filaments that possess dense patches. The myoepithelial cells of the large duct have a large process with a crablike appearance that protrudes from the cytoplasm. The myoepithelial cells of the terminal duct, by contrast, assume a relatively flat form and are approximately parallel to the epithelial-stromal junction. If the nuclei of the epithelial cells of normal mammary glands and benign breast lesions are compared with those of malignant breast lesions, the latter are primarily oval or circular in shape whereas the former often show marked notches. The predominant chromatin is heterochromatin in noncancer cells and euchromatin in cancer cells. The intracytoplasmic lumen (ICL) can be roughly divided into two types. The ICL is frequently seen in breast cancers, especially scirrhous carcinoma and lobular carcinoma. Invasive ductal carcinoma can be divided into three types: papillotubular carcinoma, solid-tubular carcinoma, and scirrhous carcinoma. Scirrhous carcinoma can be divided into two subtypes: scirrhous carcinoma in the broader sense of the term (characterized by scirrhous invasion of the stroma by papillotubular carcinoma or solid-tubular carcinoma), and scirrhous carcinoma in the narrower sense of the term (characterized by linear or cluster-like invasion of the stroma without forming ducts). Ultrastructural characteristics of scirrhous carcinoma in the narrow sense are bright cytoplasm (seen in most cells) and euchromatin (seen in all cells of this type of carcinoma). In cases of papillotubular carcinoma, solid-tubular carcinoma, and scirrhous carcinoma in the broad sense, euchromatin is predominant but sporadic cells with heterochromatin are also seen. Adenoid cystic carcinoma and carcinoid tumor of the breast are histological types of breast carcinoma that show characteristic features under an electron microscope. Ultrastructurally, the former shows a pseudocyst and true lumen whereas the latter presents numerous neuroendocrine granules within the cytoplasm. Breast carcinoma shows several ultrastructural characteristics that are useful in differential diagnosis. Therefore, it is advisable to take electron microscopic findings into account when evaluating or diagnosing breast lesions.

BRCA1 promoter methylation in sporadic breast cancer is associated with reduced BRCA1 copy number and chromosome 17 aneusomy

To explore the molecular mechanisms for the similarities between inherited and noninherited forms of breast cancer, we tested the hypothesis that inactivation of BRCA1 by promoter hypermethylation is associated with reduced gene copy number and chromosome 17 aneusomy as observed in tumors from BRCA1 mutation carriers. Using a combination of methylation-specific PCR analysis and fluorescence in situ hybridization, we observed varying degrees of promoter methylation in 39 of 131 (29.8%) primary tumors. Despite significant tumor heterogeneity, mean copy numbers of BRCA1 and CEP17 per cell were lower in methylated cases compared with unmethylated cases [1.78 versus 2.30 (P = 0.001) and 1.85 versus 2.29 (P = 0.005), respectively]. Methylation was more frequently observed in younger women (P = 0.05) with high-grade (P = 0.001), estrogen receptor-negative (P = 0.04), and progesterone receptor-negative (P = 0.01) tumors. Moreover, methylation was associated with reduced or absent BRCA1 transcripts, which was reversible in the heavily BRCA1-methylated cell line UACC3199 following treatment with 5-aza-2'-deoxycytidine and trichostatin A. We identified five CpGs at positions -533, -355, -173, -21, and +44 as critical in the reexpression of BRCA1. We conclude that BRCA1 methylation contributes to a subset of sporadic breast cancers with the resulting molecular and clinicopathologic phenotype similar to that of hereditary BRCA1-associated breast cancers. Our data support a model of carcinogenesis in which BRCA1 promoter methylation may serve as a "first hit," much like an inherited germ line mutation, and promote tumor progression down a restricted set of molecular pathways.

Differential subcellular distribution of glucose transporters GLUT1–6 and GLUT9 in human cancer: Ultrastructural localization of GLUT1 and GLUT5 in breast tumor tissues

It has been proposed that the enhanced metabolic activity of tumor cells is accompanied by an increased expression of facilitative hexose transporters (GLUTs). However, a previous immunohistochemical analysis of GLUT1 expression in 154 malignant human neoplasms failed to detect the GLUT1 isoform in 87 tumors. We used 146 normal human tissues and 215 tumor samples to reassess GLUT1 expression. A similar number of samples were used to compare the expression of GLUT2-6 and 9. The classical expression of GLUT1-5 in different normal human tissues was confirmed, however, we were unable to detect GLUT2 in human pancreatic islet cells. GLUT6 was principally detected in testis germinal cells and GLUT9 was localized in kidney, liver, heart, and adrenal. In tumor samples, GLUT1, 2, and 5 were the main transporters detected. GLUT1 was the most widely expressed transporter, however, 42% of the samples had very low-to-negative expression levels. GLUT2 was detected in 31% of the samples, being mainly expressed in breast, colon, and liver carcinoma. GLUT5 was detected in 27% of breast and colon adenocarcinoma, liver carcinoma, lymphomas, and testis seminoma samples. In situ RT-PCR and ultrastructural immunohistochemistry confirmed GLUT5 expression in breast cancer. GLUT6 and 9 are not clearly over-expressed in human cancer. The extensive expression of GLUT2 and 5 (glucose/fructose and fructose transporters, respectively) in malignant human tissues indicates that fructose may be a good energy substrate in tumor cells. Our functional data obtained in vitro in different tumor cells support this hypothesis. Additionally, these results suggest that fructose uptake could be used for positron emission tomography imaging and, may possibly represent a novel target for the development of therapeutic agents in different human cancers.

Normal and pathological breast, the histological basis

Breast tissue is heterogeneous, associating connective and glandular structures, which grow and change cyclically under hormonal regulation. Hormones are also thought to be the main determinant of the major benign and malignant pathologies encountered in the breast. Benign lesions are more frequent and fibrocystic changes are by far the most common among them. They usually associate different entities, (adenosis, fibrosis, cysts and hyperplasia) but vary in intensity and extension. Thus, their clinical and radiographic presentation is extremely different from one patient to another. Adenofibroma is the most frequent tumour. It also undergoes modifications according to hormonal conditions. About 90% of malignant tumours are primary carcinoma. The incidence of intra-ductal carcinoma has risen dramatically since the development of screening because of its ability to induce calcification. Two mechanisms could be involved in the formation of calcification: one active (tumour cell secretion of vesicles), the other passive (necrotic cell fragments are released). Invasive carcinoma comprises numerous histological types. Stromal reactions essentially determines their shape: a fibrous reaction commonly found in ductal carcinoma creates a stellate lesion while other stroma, inflammatory (medullary carcinoma), vascular (papillary carcinoma) or mucinous determine nodular lesions whose borders push the surrounding tissue. The histological features which give rise to the radiographic pattern will be emphasised.

Scanning electrochemical microscopy of living cells. 5. Imaging of fields of normal and metastatic human breast cells

Scanning electrochemical microscopy (SECM) was used to image fields of different types of human breast cells in monolayer culture. The goal of these experiments was to demonstrate the possibility of distinguishing between nontransformed human breast epithelial cells (MCF-10A) and metastatic breast cells (MDA-MB-231) by their redox activities. Imaging of densely packed cells by SECM requires approaches that differ from previously reported experiments with well-separated single cells. The combination of SECM with optical and fluorescence microscopies was used to locate individual cells in a homogeneous or heterogeneous field of cells. To establish that metastatic breast cells can be detected against a field of normal cells, the former were preloaded with fluorescent nanospheres and plated together with unlabeled MCF-10A cells. By matching SECM and fluorescence images of a selected group of metastatic cells, the level of discrimination and fidelity of the SECM signal could be shown. Several factors (distance between the electrode and the cells, cell density, choice of mediator, and its concentration) were identified that can be used to maximize the contrast between images of metastatic and nontransformed cells. These studies provide a framework for future analysis of malignant cells in human breast tissue samples.

Microfabricated silicon microneedles for nonviral cutaneous gene delivery

BACKGROUND

The skin represents an accessible somatic tissue for therapeutic gene transfer. The superficial lipophilic layer of the skin, the stratum corneum, however, constitutes a major obstacle to the cutaneous delivery of charged macromolecules such as DNA.

OBJECTIVES

To determine whether silicon-based microneedles, microfabricated via a novel isotropic etching/BOSCH reaction process, could generate microchannels in the skin of sufficient dimensions to facilitate access of lipid : polycation : pDNA (LPD) nonviral gene therapy vectors.

METHODS

Scanning electron microscopy was used to visualize the microconduits created in heat-separated human epidermal sheets after application of the microneedles. Following confirmation of particle size and particle surface charge by photon correlation spectrocopy and microelectrophoresis, respectively, the diffusion of fluorescent polystyrene nanospheres and LPD complexes through heat-separated human epidermal sheets was determined in vitro using a Franz-type diffusion cell. In-vitro cell culture with quantification by flow cytometry was used to determine gene expression in human keratinocytes (HaCaT cells).

RESULTS

The diffusion of 100 nm diameter fluorescent polystyrene nanospheres, used as a readily quantifiable predictive model for LPD complexes, through epidermal sheets was significantly enhanced following membrane treatment with microneedles. The delivery of LPD complexes either into or through the membrane microchannels was also demonstrated. In both cases considerable interaction between the particles and the epidermal sheet was observed. In-vitro cell culture was used to confirm that LPD complexes mediated efficient reporter gene expression in human keratinocytes in culture when formulated at the appropriate surface charge.

CONCLUSIONS

These studies demonstrate the utility of silicon microneedles in cutaneous gene delivery. Further studies are required to elucidate fully the influence of the physicochemical characteristics of gene therapy vectors, e.g. particle diameter and surface charge, on their diffusion through microchannels and to quantify gene expression in vivo.

PEA3 transcription factors are expressed in tissues undergoing branching morphogenesis and promote formation of duct-like structures by mammary epithelial cells in vitro

The genetic program that controls reciprocal tissue interactions during epithelial organogenesis is still poorly understood. Erm, Er81 and Pea3 are three highly related transcription factors belonging to the Ets family, within which they form the PEA3 group. Little information is yet available regarding the function of these transcription factors. We have previously used in situ hybridization to compare their expression pattern during critical stages of murine embryogenesis [Oncogene 15 (1997), 937; Mech. Dev. 108 (2001), 191]. In this study, we have examined the expression of PEA3 group members during organogenesis of the lung, salivary gland, kidney, and mammary gland. In all of these developmental settings, we observed a tight correlation between branching morphogenesis and the expression of specific members of the PEA3 group. To assess the functional relevance of these findings, Erm and Pea3 were overexpressed in the TAC-2.1 mammary epithelial cell line, which has the ability to form branching duct-like structures when grown in collagen gels. We found that overexpression of Erm and Pea3 markedly enhances branching tubulogenesis of TAC-2.1 cells and also promotes their invasion into a collagen matrix. Collectively, these findings suggest that the differential expression of PEA3 group transcription factors has an important role in the regulation of branching morphogenesis and raise the question of their implication in branching signaling.

Detection of interferon-gamma-inducible chemokines in human milk

AIM

To assess the immunological role of human milk by analysing the concentrations of interferon-gamma-inducible protein of 10 kda (IP-10) and monokine induced by interferon-gamma (MIG) in human milk from mothers of preterm and term infants.

METHODS

IP-10 and MIG levels of colostrum, early milk, mature milk and sera were measured by enzyme-linked immunosorbent assay (ELISA). IP-10 and MIG mRNA expression levels in cellular components of human milk were determined by RT-PCR. IP-10 and MIG protein expression in mammary gland tissues was analysed by immunohistochemistry.

RESULTS

Significant amounts of IP-10 and MIG were detected in human milk. The concentrations of IP-10 and MIG in colostrum and early milk were significantly higher than those of sera from healthy controls or lactating mothers. These chemokine concentrations in colostrum and early milk were significantly higher than those of mature milk. Premature delivery or pregnancy complications of mothers had no significant correlation with these chemokine concentrations in breast milk. There were significant correlations between MIG and interferon-gamma (IFN-gamma) or IP-10 levels (p < 0.001) in human milk. Expression of IP-10 and MIG genes and proteins in the milk cells as well as in mammary gland epithelial tissues was detected by RT-PCR and immunohistochemistry.

CONCLUSION

IP-10 and MIG in human milk, probably derived from milk cells and mammary gland epithelial cells, may contribute to the migration and activation of intestinal T lymphocytes to enhance mucosal immunity during the early neonatal period.

Zinc transporters 1, 2 and 4 are differentially expressed and localized in rats during pregnancy and lactation

Zinc metabolism is controlled within relatively restricted limits throughout the life cycle. Expression and localization of zinc transporters 1, 2 and 4 during pregnancy and lactation in small intestine, mammary gland and liver of the rat were investigated using Northern analysis, Western blotting and immunohistochemistry. In maternal tissues, zinc transporter 4 was the most widely expressed among these zinc transporters in the tissues examined. In small intestine and liver, zinc transporter 4 increased from levels found during late gestation, but zinc transporter 1 did not. Zinc transporter 2 expression in small intestine was transient, being highest around parturition, and was not detected in liver. Immunohistochemistry revealed unique patterns of zinc transporter localization at different stages of development. In the placenta, zinc transporters 1 and 4 were found concentrated along the villous visceral splanchnopleure. In the mammary gland, zinc transporter 4 was most abundant in cells surrounding the alveolar ducts and oriented to the basement lamina. All three transporters were highly expressed in neonatal small intestine, principally near the apical surface, but zinc transporters 1 and 4 increased in abundance at the basolateral surface during development. Zinc transporter 2 was oriented apically, directly adjacent to the microvilli of enterocytes. Within the intestine, expression of each transporter was limited to enterocytes. These results support a role for these transporters in maintaining an adequate zinc supply derived from the maternal diet for zinc acquisition and use by the fetus and neonate.

A novel method of imaging lysosomes in living human mammary epithelial cells

Cancer cells invade by secreting degradative enzymes which, under normal conditions, are sequestered in lysosomal vesicles. The ability to noninvasively label lysosomes and track lysosomal trafficking would be extremely useful to understand the mechanisms by which degradative enzymes are secreted in the presence of pathophysiological environments, such as hypoxia and acidic extracellular pH, which are frequently encountered in solid tumors. In this study, a novel method of introducing a fluorescent label into lysosomes of human mammary epithelial cells (HMECs) was evaluated. Highly glycosylated lysosomal membrane proteins were labeled with a newly synthesized compound, 5-dimethylamino-naphthalene-1-sulfonic acid 5-amino-3,4,6-trihydroxy-tetrahydro-pyran-2-ylmethyl ester (6-O-dansyl-GlcNH2). The ability to optically image lysosomes using this new probe was validated by determining the colocalization of the fluorescence from the dansyl group with immunofluorescent staining of two well-established lysosomal marker proteins, LAMP-1 and LAMP-2. The location of the dansyl group in lysosomes was also verified by using an anti-dansyl antibody in Western blots of lysosomes isolated using isopycnic density gradient centrifugation. This novel method of labeling lysosomes biosynthetically was used to image lysosomes in living HMECs perfused in a microscopy-compatible cell perfusion system.

Effect of 4-hydroxytamoxifen isomers on growth and ultrastructural aspects of normal human breast epithelial (HBE) cells in culture

In the search for a breast cancer prevention strategy which would avoid undesirable effects of orally administered tamoxifen, the percutaneous administration of the highly active metabolite 4OHTamoxifen (4OHTam) has been proposed. Percutaneous 4OHTam penetrates the skin to reach breast tissues. It, thus, avoids the hepatic first pass effect, and offers an optimal local/systemic effect. However, trans-4OHTamoxifen can spontaneously isomerize into the cis-isomer, which may have estrogen agonist action. The aim of this study was to examine the effect of cis-4OHTam on normal human breast epithelial (HBE) cells in culture. Spontaneous isomerization of trans- into cis-4OHTam occurred within 24-48h, but stabilized rapidly at a trans/cis ratio of 70/30, whether in stock solution, culture medium or cultured cells. The cis-4OHTam did not stimulate HBE cell growth according to histometric cell counts and scanning electron microscopy analysis, but inhibited E(2)-induced cell growth, albeit two to three times less than trans-4OHTam. In conclusion, spontaneous isomerization of trans- to cis-4-OHTam is limited and 4OHTam retains a marked antiestrogenic effect. It may prove to be a useful alternative to tamoxifen in breast cancer prevention, especially if administered percutaneously.

Carrageenan-induced inclusions in mammary myoepithelial cells

The purpose of this investigation was to characterize the ultrastructural changes that occur in mammary myoepithelial cells (MMEC) following exposure in tissue culture to low concentrations of lambda-carrageenan, a sulfated polysaccharide commonly used as a food additive. MMEC were obtained from reduction mammoplasty, grown in tissue culture, exposed for varying durations to low concentrations (0.0014%-0.0001%) of lambda-carrageenan, and examined by transmission electron microscopy, following staining for acid phosphatase and for aryl sulfatase. Carrageenan appeared to enter the cells by membrane-associated endocytic vesicles and accumulate in endosomes and lysosomes. Unusual lamellar inclusions were identified within lysosomes of the MMEC, and lysosomal vacuolation arose in association with the inclusions. The observed changes appeared to lead to destruction of the MMEC by release of proteolytic enzymes from the distorted lysosomes, similar to the process observed in lysosomal storage diseases.

Proteoglycan–collagen associations in the non-lactating human breast connective tissue during the menstrual cycle

The human mammary gland undergoes a sequence of histological changes in both epithelial and stromal compartments during the menstrual cycle. Swelling and unswelling of the breast stromal tissue is a characteristic feature of the two phases of the cycle and is mediated by changes in the water content of sulfated proteoglycans in the matrix between the fibrils. In an ultrastructural study we investigated the distribution of sulfated proteoglycans identified as cupromeronic blue-positive needle-like structures and measured the distance between the dermatan sulfate-proteoglycan attachment sites at the d-bands of the collagen fibrils in the loose intralobular connective tissue and in the dense interlobular connective tissue. We characterized the dermatan sulfate proteoglycan by enzyme digestion and by immunogold-labeled antibody. In the follicular phase a relatively constant distance of 46 nm between neighboring proteoglycan attachment sites was found, while in the luteal phase the measured distances are strikingly variable and exceed the follicular value by up to 9 nm. This difference of the two cycle phases is more evident in the loose than in the dense connective tissue. Possibly the changes of the fibril-attached proteoglycans in the luteal phase reflect an influence of the higher water content of the matrix leading to a probably torsional swelling of the collagen fibril.

Cell proliferation in bovine mammary epithelium: identification of the primary proliferative cell population

Histologic analyses indicate that a lightly staining cell population present in mammary parenchyma may function as mammary stem cells. We performed an analysis of mammary epithelial cell proliferation in prepubertal bromodeoxyuridine (BrdU)-injected Holstein heifers to investigate this hypothesis. We observed light, dark, and intermediate staining cells in histologic sections stained with basic fuschin and azure II. Light cells comprised 10% of the total parenchymal cell population but accounted for 50% of the cell proliferation. Intermediate cells comprised 60% of the cell population and 43% of proliferating cells. Dark cells comprised 30% of the parenchymal cell population but only 7% of proliferating cells. The distribution of BrdU+ cells across basal, embedded, and lumenal parenchymal cell layers was correlated with the fraction of total parenchymal cells present in each layer (r=0.99). However, the proportion of mitotic cells observed in the basal cell layer was only half of what would be predicted by the BrdU-labeling data. This observation suggests that some basal cells either arrest in G(2) or migrate into the suprabasal epithelial layers before undergoing mitosis. These results strongly support the concept that lightly staining mammary parenchymal cells are the primary proliferative cell population.

Endocytic prolactin routes to the secretory pathway in lactating mammary epithelial cells

Plasma-borne prolactin is carried from blood to milk by transcytosis across the mammary epithelial cell through the endocytic and secretory pathways. To determine the precise route of prolactin endocytosis, intracellular transport of biotinylated prolactin was monitored, in parallel with endocytosis of fluorescein isothiocyanate-conjugated dextran and IgG, by using pulse-chase experiments in lactating mammary fragments and in enzymatically dissociated acini. Biotinylated prolactin was sorted to vesiculo-tubular organelles whereas dextran was very rapidly carried to the lumen and IgG remained accumulated in the basal region of cells. To determine whether prolactin uses routes into and across the Golgi and trans-Golgi network, localisation of biotinylated prolactin was combined with the immunofluorescence detection of caseins and, respectively, p58 and TGN38. Biotinylated prolactin strongly colocalised with caseins during a chase but not all or only very little with p58 and TGN38. To characterise the organelles involved in transcytosis, gold-labelled prolactin, experimentally accumulated in late endosomes and which recovered a normal transport, was localised by electron microscopy. In mammary fragments incubated at low temperature, and in mammary fragments from rats fed with a lipid-deprived diet, transport of gold-labelled prolactin was restored by increasing the temperature and by adding arachidonic acid, respectively. These data demonstrate that a sorting occurs very rapidly between prolactin, dextran and IgG. They suggest that prolactin may reach the biosynthetic pathway after direct fusion between multivesicular bodies and secretory vesicles.

Ultrastructural localization of laminin and type IV collagen in normal human breast

The ability of carcinomas to invade and metastasize depends in part on their passage through basement membranes. Two of the major components of basement membranes are type IV collagen and laminin and these have been extensively studied by light microscopical immunocytochemical techniques to investigate alterations in their distribution in human breast carcinomas [1-3]. Breaks in the epithelial basement membrane associated with malignant epithelial tumors have been reported [3, 4]. However, these breaks are based on immunocytochemical observations and have not been correlated with basement membrane morphology. By light microscopical techniques there is no evidence of type IV collagen or laminin between myoepithelial cells or between myoepithelial and epithelial cells and they appear to be restricted to the basement membrane surrounding the entire ductule of the breast. By electron microscopy the basement membrane region contains a linear, homogeneous, electron-dense region (lamina densa) beneath a clear zone (lamina lucida) directly beneath the epithelial and myoepithelial cells of the breast ductule. These two regions constitute the basal lamina. Hemidesmosomes are present on the basal aspect of myoepithelial cells where fine filaments connect these regions to the adjacent basal lamina. The extracellular matrix components laminin and type IV collagen have both been localized in the basement membrane of the normal human breast ductule. Breaks in the continuity of these components occur in breast carcinomas and have been implicated in tumor metastasis. Using a postembedding ultrastructural immunogold technique, laminin and type IV collagen were distributed within the basal lamina surrounding the normal human breast ductule. Both components were present diffusely along the basal lamina and were not localized to particular regions, and neither were present between epithelial and myoepithelial cells. Laminin binding of these cells thus probably occurs only at the basal aspect where they are in contact with the basal lamina and is not involved in the cell-cell adhesion between epithelial and myoepithelial cells. This study provides a basis for further ultrastructural investigations of extracellular matrix components in normal and neoplastic breast tissue.

Nuclear magnetic resonance-visible lipids induced by cationic lipophilic chemotherapeutic agents are accompanied by increased lipid droplet formation and damaged mitochondria

Proton nuclear magnetic resonance (NMR) spectroscopy, histological lipid staining, and electron microscopy were used to assess the biochemical and structural changes induced by treating the cultured human breast cell line HBL-100 with the cationic lipophilic phosphonium salts p-(triphenylphosphoniummethyl) benzaldehyde chloride (drug A) and [4-(hydrazinocarboxy)-1-butyl] tris-(4-dimethylaminophenyl) phosphonium chloride (drug B). The major biochemical change detected by (1)H NMR in drug-treated cells was a significant time- and concentration-dependent increase in lipid acyl chain resonances arising from mobile lipids. The amount of NMR-visible lipid strongly correlated with morphometric measurements of oil red O-staining lipid detected in the cytoplasm by light microscopy. Ultrastructural investigations revealed substantial damage to mitochondria and the progressive development of lipid droplets accompanied by end-stage autophagic vacuoles, in the form of densely staining myelinoid bodies, after treatment of HBL-100 cells with drug B at the IC(50). No apparent increase in acid phosphatase activity was observed using electron microscopy, indicating that the accumulation of phospholipids in myelinoid bodies may result from substrate inundation of the lysosome, rather than increased lysosomal activity. These results indicate a potential role for lysosomal lipid catabolism in the formation of NMR-visible lipids in models of cytotoxic insult.

Rho regulates p21(CIP1), cyclin D1, and checkpoint control in mammary epithelial cells

The small GTPase Rho is important for cell cycle progression and Ras transformation in fibroblasts. However, it is unclear whether Rho is needed for proliferation in other cell types, and its targets in promoting normal cell cycle progression are unknown. Here, we demonstrate that Rho is required for G1 to S progression in MCF10A mammary epithelial cells, both in response to EGF and in response to oncogenic Ras. We describe two effects of Rho, the repression of p21(CIP1) and the induction of cyclin D1, that may underlie its role in promoting S phase entry. The Rho inhibitor, C3 exotransferase, induced p21(CIP1) both in EGF-stimulated and V12Ras-expressing cells. In addition, C3 blocked EGF-stimulated cyclin D1 promoter activity whereas V14RhoA induced the cyclin D1 promoter and cooperated with V12Ras in cyclin D1 induction. Finally, a high proportion of cells co-expressing V14RhoA and V12Ras displayed lobulated, polyploid nuclei that were actively synthesizing DNA. Our results demonstrate that Rho plays a fundamental role in promoting Ras-dependent S phase entry in mammary epithelial cells, whether in response to normal or oncogenic signaling, and indicate that in cells expressing oncogenic Ras, the activation of Rho diminishes p21(CIP1) expression, increases cyclin D1 promoter activity, and uncouples DNA synthesis from mitosis.

Increased risk of local recurrence is associated with allelic loss in normal lobules of breast cancer patients

Allelic losses characteristic of tumor cells, when displayed by morphologically normal terminal ductal lobular units (TDLUs) adjacent to carcinoma [G. Deng et al., Science (Wash. DC), 274: 2057-2059, 1996], may indicate an extended field of increased cancer susceptibility within the affected breast tissue. We investigated this possibility by asking whether the presence of loss of heterozygosity (LOH) at chromosome 3p11-26 in histologically normal TDLUs (3pLOHn) could lead to an increased risk of local tumor recurrence. We assessed LOHs in normal TDLUs adjacent to 48 informative cases of early-stage invasive breast cancer samples and found 3pLOHn in approximately 25% (13 of 48) of patients whose tumors had 3pLOH in this region. Our analyses suggest that the most frequent region of LOH is localized at 3p24.3. We also demonstrate, using a Cox proportional hazards regression model, that the presence of 3pLOHn was the only variable significantly related to local tumor recurrence, leading to a 3.9-5.2-fold increase in the hazard ratio (P < 0.05). The time to recurrence was longer in such cases than in those without 3pLOHn, suggesting de novo tumor development. These data provide a strong rationale to assess histologically normal breast tissue at the margins of surgically excised cancers for molecular predictors of local recurrence after breast-conserving treatment.

Effects of anabolic implants of oestradiol alone or in combination with trenbolone acetate on the ultrastructure of mammary glands in female lambs regarding their interference in prolactin secretion

The side-effects of anabolic steroid implants on mammary gland ultrastructure were evaluated in female lambs treated with oestradiol (n = 10) and with oestradiol plus trenbolone acetate (n = 10). Ten non-implanted lambs were used as controls. Apart from the ultrastructural study of the mammary gland, an assessment of the prolactin pituitary cell population was carried out by immunological methods. Our results showed that oestrogenic implants exert stimulating effects on mammary gland development, both by activating the synthesis process at mammary gland cell levels and by increasing prolactin pituitary production. Nevertheless, there was no evidence of secretory products in the lumen of the gland. Implants containing trenbolone acetate counteracted the mammary stimulus of oestrogens showing ultrastructural images of cell autolysis and necrosis.

[Ultrastructural stereologic parameters of epithelial cells of alveolar ducts in the pre-and postovulatory female breast]

Stereological characteristics of ductular parenchyma epithelial cells are analysed ultrastructurally on 8 cases of normal breast tissue. Different physiological states have been compared and tahat pre- and postovulatory. Volume density (VV), surface density (SV) and specific surface density (SV/VV) of nuclei and epithelial cells cytoplasm have been stereologically examined and compared. Postovulatory, the volume density (VV) and surface density (SV) of nuclei as well as specific surface density (SV/VV) of epithelial cells cytoplasm are much less, while a volume density (VV) of epithelial cells cytoplasm is greater.

Changes in adhesive properties of epithelial cells during early morphogenesis of the mammary gland

Previous studies have demonstrated that cell adhesion systems are downregulated in epithelial buds at the earliest stages of submandibular gland and hair follicle development, but are restored at subsequent stages. Here it is shown that epithelial cell adhesion systems are also remodeled during early mammary gland development. Immunofluorescence and electron microscopy of the mouse mammary bud demonstrated that cell-cell adhesion systems were hardly detectable, with significant downregulation of expression of desmosomal molecules, but not of E-cadherin and beta-catenin. Hemidesmosomal structures were also rarely found, although their component molecules were expressed. Differences in cell adhesivity between cells of the mammary bud and those of the overlying epidermis were shown by the finding that the mammary cells formed smaller aggregates than the epidermal cells and were not randomly mixed with the epidermal cells. At subsequent stages, the mammary epithelium restored cell-cell adhesion systems along with de novo expression of tight junction molecules. These data, together with previous findings, indicate that remodeling of epithelial cell adhesion systems is a general feature underlying the early development of several ectoderm-derived organs and support the idea that segregation and rearrangements of cells are involved in early epithelial morphogenesis.

Rare case of biphasic tumor of the breast with prominent CD34-positive spindle cells

We report an unusual case of biphasic tumor of the breast with prominent CD34-positive spindle cells. A 53-year-old woman presented with a mass in her right breast. Following an incisional biopsy, a partial mastectomy was done. Histologically, the tumor was a biphasic variant of a malignant spindle cell tumor of the breast. The lack of a leaf-like structure, together with the apparent myoid features of the spindle-shaped tumor cells, made it difficult to distinguish from malignant phyllodes tumor and from myoepithelial carcinoma. Immunohistochemistry revealed the spindle-shaped tumor cells to be myofibroblastic, but not myoepithelial in nature, ultimately categorizing this tumor as a malignant phyllodes tumor with prominent myofibroblastic differentiation.