Human mammary epithelial cells undergo squamous differentiation in serum-free three-dimensional culture upon loss of growth activity

Normal human mammary epithelial cells (HMEC) isolated from surgically resected breast tissues were cultured under serum-free conditions using MCDB 170 medium. With the increase in the number of passages, in particular after the 5th passage, the number of enlarged, flattened and vacuolated cells increased while cell proliferation decreased. The senescent cells occasionally had keratohyaline granules in the cytoplasm and were positive in immunohistochemistry for keratinizing squamous epithelium-specific cytokeratin 10. When HMEC were cultured between floating double-layered collagen gels, the cells lost growth activity, showed marked stratification, and became positive for carcinoembryonic antigen (CEA). The stratified cells underwent squamous differentiation and tonofilament bundles appeared around the nuclei. The stratification and squamous differentiation of HMEC were observed within seven days after transfer to the three-dimensional culture, regardless of the number of passages. These results indicate that the HMEC in vitro ultimately differentiate into squamous epithelia and also that there is a close relationship between the squamous-type differentiation and the loss of cell proliferation.

Mast cell association with collagen fibres in human breast stroma

Whirl-like structures consisting of strands and bundles of collagen fibres with a central space are described in human breast stroma. Association between these structures and connective tissue mast cells is demonstrated. Mast cells in these whirls, in contrast to those in loose connective tissue, showed signs of secretory activity. On ultramicroscopy some showed electron-dense bud-like structures at the edge of the cell, and between this and adjacent collagen bundles. In the absence of cytoplasmic cover association was demonstrated between the surface of a mast cell granule and a band of collagen fibres in the stroma. In vitro production of collagen fibres was reported in 1952 on the addition of heparin powder to soluble collagen. The mechanism of that reaction was not further defined. Neither, as yet, is that underlying the present findings. The products of mast cell granules would appear to be common to both. It is suggested that these findings may represent an alternative pathway for collagen deposition in vivo, as in vitro.

Integrin and Arg-Gly-Asp dependence of cell adhesion to the native and unfolded triple helix of collagen type VI

Pepsin-solubilized collagen VI in triple-helical and heat-denatured, unfolded form was shown to promote Mg(2+)- and Mn(2+)-dependent attachment and spreading of various cell lines. On the triple-helical substrate no inhibition of cell adhesion was observed with several synthetic RGD peptides except in the case of A375 melanoma cells. In contrast, adhesion to the unfolded substrate was highly sensitive to RGD inhibition. Nine synthetic peptides were designed according to 10 RGD sequences present in the triple-helical sequence of human collagen alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains. Only one peptide, corresponding to the C-terminal end of alpha 3(VI) chain, showed substantial inhibitory activity, whereas several peptides were active in direct adhesion assays when used as albumin conjugates. Inhibition tests with antibodies to integrin subunits, affinity chromatography, and ligand binding with purified integrins (alpha 1 beta 1, alpha 2 beta 1, alpha V beta 3, and alpha IIb beta 3) were used to identify collagen VI receptors. Binding to the triple-helical substrate is mediated by alpha 1 beta 1 and alpha 2 beta 1 integrins. Binding of both integrins to collagen VI was weaker than that to collagens I and/or IV. Recognition of the denatured substrate is mediated by beta 1 and beta 3 integrins. Activity was shown for alpha 5 beta 1 and alpha V beta 3 and weakly for alpha IIb beta 3 but not all alpha subunits possibly involved were identified. Distinct sets of receptors were also involved in A375 cell binding to triple-helical (beta 1-mediated) and denatured (beta 3-mediated) collagen VI, even though in this case both interactions could be efficiently inhibited by RGD peptides.

Collagenous spherulosis. Report of a case with diagnosis by fine needle aspiration biopsy with immunocytochemical and ultrastructural observations

Collagenous spherulosis (CS) is a benign breast lesion usually seen in association with other benign proliferative processes in the breast. To the best of our knowledge, this is the second fine needle aspiration (FNA) cytologic report of CS and the first with corresponding immunocytochemical and ultrastructural studies performed on the subsequent biopsy material. Cytologically, the aspirate consisted of scattered, metachromatically staining hyaline globules seen best with Diff-Quik stain in intimate association with numerous groups of benign ductal cells some of which had a papillary configuration. The globules exhibited periodic acid-Schiff positivity. A subsequent excisional biopsy confirmed the cytologic impression and revealed a multifocal process of ductal papillomas and papillomatosis containing numerous eosinophilic spherules with morphologic features and histochemical staining reactions typical of CS. Electron microscopic and immunoperoxidase studies suggest the spherules to be composed predominantly of basement membrane proteins, specifically type IV collagen, laminin and fibronectin, and to be derived principally from myoepithelial cells. Although CS has been found primarily in benign breast lesions, it can be found in other organs and in association with both benign and malignant processes. The differential diagnosis of other breast lesions that can be confused with CS on FNA biopsy is presented.

Epidermal growth factor receptor in breast cancer. Comparison with non malignant breast tissue

Epidermal growth factor receptors were measured using a radioligand binding assay in membrane preparations from 67 cancer and 25 non-malignant tissues. The binding characteristics of EGFr were similar in tumour and normal breast membranes. The concentrations were significantly higher in non-malignant tissue than in cancer. EGFr concentrations were directly correlated with steroid receptors in non-malignant tissue, whereas in cancer an inverse correlation between EGFr and steroid receptors was found.

Retinoblastoma and p53 gene product expression in breast carcinoma: immunohistochemical analysis and clinicopathologic correlation

We examined 100 breast cancers for retinoblastoma (Rb) and p53 protein expression by immunohistochemistry using the PMG3.245 and PAb 1801 antibodies. We assessed percentages of reactive cells and their intensity, as well as staining patterns. The results were correlated with neu protein reactivity and a panel of variables, including age, tumor size and type, nuclear grade, estrogen receptor/progesterone receptor content, and lymph node status. Retinoblastoma protein negativity, either partial or complete, was noted in 47% of cases. Surprisingly, a relatively stronger Rb reaction was seen in some high nuclear grade tumors. p53 positivity was found in 23% of cases and was a significant predictor of Rb loss. p53 also was correlated with poorly differentiated (nuclear grade III) neoplasms and neu expression but not with negative ER status. Tissue distribution profiles for Rb-negative and p53-positive cells were variable in this series, with both uniform and heterogeneous patterns observed. This suggests that Rb and p53 alterations may represent early or late events in transformation. Our findings further implicate Rb and p53 derangements in mammary oncogenesis.

Characterization of normal breast epithelial cells in primary cultures: differentiation and growth factor receptors studies

The growth and differentiation of normal human mammary epithelial cells (HMEC) were studied after propagation of serial cultures from breast tissue biopsies from 42 mammoplasty patients. Cells were grown for up to 7 mo. in low calcium medium. HMEC cultures displayed heterogeneous growth patterns, according to the average doubling time of 44 +/- 6 h for 32 generations. Proliferation peaked at Day 30. HMEC maintained a normal karyotype and were organized in ductlike structures when cultured in collagen gel matrix. The cultures retained several phenotype traits of the epithelial lineage, including the expression of cytokeratins 18 and 19, specific mammary gland antigens, as shown by indirect HMEC immunostaining by the monoclonal antibodies DF3, EMA, 7B10, and 1BE12. Estrogen receptors were undetectable, whereas progesterone receptors were present at very low density. High-affinity cell surface receptors for epidermal growth factor (EGF) (Kd = 1.1 x 10(-10) M) were observed at a density of 50,000 to 100,000 sites per cell. Accordingly, [3H]thymidine incorporation in HMEC was optimally stimulated by EGF at concentrations of 10(-11) to 10(-10) M. HMEC were also seen to possess functional VIP receptors linked to the adenylate cyclase system, as we previously observed in seven human breast cancer cell lines. These results show that long-term cultures of HMEC provide useful models for studying the growth and differentiation of the normal human mammary gland, and the role of growth factors and hormones in these functions.

Morphology and intermediate filament composition of human mammary epithelial cells treated with stable butyrate derivative

A new stable butyrate derivative monobut-3 was previously shown to inhibit proliferation and promote differentiation in human mammary established cell lines. The present study on monobut-3's effects on mammary epithelial cells cultured from human non-malignant and malignant breast tissues demonstrated pronounced morphological alterations suggestive of cellular differentiation. In addition, some degree of architectural differentiation was also evident in treated primary cultures. Monobut-3 did not affect the expression of vimentin and cytokeratin 18 when assessed in human breast cell lines expressing one or both types of intermediate filaments. However, it did induce expression of cytokeratin 19, characteristic of fully differentiated mammary cells, in one of the two cell lines devoid of this cytokeratin subtype. Furthermore, the network of intermediate filaments was often more largely extended in cells treated with monobut-3 than in untreated ones. These results indicate that monobut-3 can induce subtle changes in intermediate filaments which may contribute to its ability to promote differentiation in human mammary cells.

Preferential chromosome loss in human papilloma virus DNA-immortalized mammary epithelial cells

Human papilloma virus (HPV) DNA-immortalized human mammary epithelial cells may provide a model system for studying the molecular basis of immortalization and its role in breast neoplasia. Cytogenetic analyses were performed on clones derived from HPV 16- and HPV 18-immortalized human mammary epithelial cells. The majority of the clones contained near-diploid karyotypes. The single most frequent whole-chromosome loss was that of chromosome 19. Regions that showed preference for deletion and/or translocation included 2pter, 11qter, and 15pter. Evidence of chromosome 19 loss was confirmed by polymerase chain reaction (PCR)-generated, chromosome 19-specific, dinucleotide microsatellite repeat polymorphism analysis.

Multinucleated stromal giant cells in adolescent gynaecomastia

Bizzare multinucleated stromal giant cells were observed in a case of adolescent gynaecomastia. Similar cells have been described in the female breast in both benign and malignant conditions where they are thought to originate either from reactive stromal cells or from the mononuclear phagocyte system, respectively. Immunohistochemistry and electron microscopy in this case support the idea that they originate from stromal fibroblasts. Their occurrence in gynaecomastia is further evidence that these changes in stromal cells may be due to hormonal influences.

Changes in the extracellular matrix of the normal human breast during the menstrual cycle

The normal human mammary gland undergoes a well defined sequence of histological changes in both epithelial and stromal compartments during the menstrual cycle. Studies in vitro have suggested that the extracellular matrix surrounding the individual cells plays a central role in modulating a wide variety of cellular events, including proliferation, differentiation and gene expression. We therefore investigated the distribution of a number of extracellular matrix molecules in the normal breast during the menstrual cycle. By use of indirect immunofluorescence, with specific antibodies, we demonstrated that laminin, heparan sulphate proteoglycan, type IV collagen, type V collagen, chondroitin sulphate and fibronectin undergo changes in distribution during the menstrual cycle, whereas collagen types I, III, VI and VII remain unchanged. These changes were most marked in the basement membrane, sub-basement membrane zone and delimiting layer of fibroblasts surrounding the ductules where basement membrane markers such as laminin, heparan sulphate proteoglycan, and type IV and V collagens appear greatly reduced during the mid-cycle period (days 8 to 22). These results suggest that some extracellular matrix molecules may act as mediators in the hormonal control of the mammary gland, whereas others may have a predominantly structural role.

Type 1 IGF receptor in human breast diseases

The first step of the action of IGF1 and IGF2 (IGFs) is their binding to membrane receptors. IGF binding sites have been characterized by competitive binding and cross-linking techniques in human breast cancer cell lines as well as in human breast cancers and in human benign breast diseases. IGF2 is a good competitor of 125I-IGF1 binding to IGF1-R; insulin competes but with a potency 1/100 lower than the IGF1 potency. Chemical cross-linking experiments revealed that the apparent molecular weight of the IGF1-binding sites is 130,000. Alpha IR-3, a murine monoclonal antibody against the IGF1-R, blocks IGF1-binding to this receptor. This antibody inhibits the IGF1-stimulated growth of breast cancer cells. Therefore, the IGF1 specific binding sites correspond to the previously described type 1 IGF receptors (IGF1-R) in normal tissues. Cross-linking experiments with labeled IGF2 resulted in a major band of apparent Mr 260,000-270,000 that was inhibited by unlabeled IGF2 but not by insulin, and corresponds to the type 2 IGF receptor; a second band of apparent Mr 130,000 was inhibited by excess IGFs and insulin (Type I receptor). The alpha-IR3 inhibition of the IGF2 mitogenic activity suggest that IGF1-R partially mediates the growth effect of IGF2 in these cells. We and others have demonstrated that most breast cancer cell lines contain IGF1-R.(ABSTRACT TRUNCATED AT 250 WORDS)

Peroxisomal enzymes in normal and tumoral human breast

The presence of peroxisomes and their enzymatic content were investigated and compared in healthy and neoplastic human breast epithelial cells using cytochemical studies at the ultrastructural level as well as Western blot and biochemical analyses. Ultrastructural cytochemistry revealed the presence of these organelles in both normal and neoplastic breast tissues. Their mean diameter was 0.27 +/- 0.11 micron. No significant difference was noted between numbers of peroxisomes in normal and neoplastic breast epithelia. Catalase, D-amino acid oxidase, and urate oxidase were found to be expressed in mammary carcinoma and in surrounding non-malignant tissue when the postnuclear supernatant fractions prepared from homogenates were assessed by Western blot techniques. Their specific activities and that of fatty acyl CoA oxidase as determined spectrophotometrically were found to be diminished in the tumour when compared with the control tissue. On the other hand, no significant difference was found in the specific activity of the L-alpha-hydroxy acid oxidase of normal and neoplastic human breast tissues. Investigations of the relationship between peroxisomal enzymes and tumour grade revealed that catalase, urate oxidase, and fatty acyl CoA oxidase activities in breast neoplastic tissues belonging to grade III were significantly lower than in the adjacent normal tissues.

Dimensions of capsular collagen fibrils: image analysis of rapid compared with slow tissue expansion for breast reconstruction

Thirty women who were to undergo breast reconstruction by tissue expansion were randomly divided into two groups. Those in the first group were to undergo expansion once a day (rapid expansion) and the second group once a week (slow expansion). When the expanders were replaced by permanent prostheses, biopsy specimens were taken from the capsules around the expanders, and were examined by transmission electron microscopy at a magnification x 22,000. The diameters of the collagen fibrils in the capsules were analysed by an interactive image analysis system and measured. An analysis of variance was performed on a test series to optimize the sample. Ninety fibrils from each patient (two patients were excluded), were analysed and there were no significant differences in collagen fibrillar diameters (about 50 nm) between those who had undergone rapid or slow expansion, or between patients who had also undergone radiotherapy to the chest wall and those who had not. These results indicate that the collagen fibrils may still be in a transitional stage, and that further longer term studies are desirable. It is difficult, however, to see how they could be justified ethically in patients who are otherwise well.

Endocrine cells in a normal breast and non-cancerous breast lesion

The authors confirmed the presence of endocrine cells for the first time in a normal breast as well as in a non-cancerous lesion of the breast. One hundred and eighty-eight blocks of normal breast tissues in 44 cases and 74 blocks of non-cancerous lesions in 35 cases were examined. Argyrophil cells were found in one block from a normal breast and in one block from a phyllodes tumor. Argyrophil cells in the normal breast showed positive reaction to anti-endocrine granule constituent (EGC) antibody with immunohistochemical method. Argyrophil cells found in the phyllodes tumor gave positive reaction to both anti-EGC and anti-serotonin antibodies. The present study is thought to be the first report in the literature of serotonin-positive cells in a non-cancerous breast lesion, a phyllodes tumor.

Comparative features of carcinoma in situ and atypical ductal hyperplasia of the breast on fine-needle aspiration biopsy specimens

With the use of fine-needle aspiration biopsy to evaluate non-palpable breast lesions, an increasing number of cases of ductal carcinoma in situ (DCIS) are encountered. The authors previously demonstrated that it is not possible to distinguish definitively between DCIS and invasive ductal carcinoma on fine-needle aspiration biopsy. To determine whether DCIS could be separated from atypical ductal hyperplasia (ADH), the authors identified all cases of exclusive DCIS or ADH with fine-needle aspiration biopsy before surgery. Sixteen cases of ADH and 19 cases of DCIS were identified. Of these, 12 in each category were sufficiently cellular to allow evaluation of architectural and cytologic features. Cases of ADH were more likely to be diagnosed as negative or atypical (11 of 12); in contrast, DCIS was more likely to be designated as suspicious or positive (9 of 12). Architectural and cytologic features characteristic of ADH included cells arranged in flat cohesive sheets, distinct cell borders, and myoepithelial cells. Those features characteristic of DCIS were single cells representing more than 10% of atypical cells, cellular dyshesion, and inflammatory background, coarsely granular chromatin, and nuclear pleomorphism. Many other features were not useful in separating ADH from DCIS. Based on this small series, it appears that the distinction between some cases of DCIS and ADH may be possible on fine-needle aspiration biopsy.

Immunohistochemical localization of integrins in the normal, hyperplastic, and neoplastic breast. Correlations with their functions as receptors and cell adhesion molecules

Integrins comprise a family of transmembrane glycoproteins that modulate cell-matrix and cell-cell relationships by acting as receptors to extracellular protein ligands, and also as direct adhesion molecules. The authors studied by immunohistochemistry the distribution of the alpha 1-6,v and the beta 1,3,4 subunits of integrins in samples of normal breast, the spectrum of fibrocystic disease (FCD), and representative benign and malignant neoplasms. Monoclonal antibodies (Mabs) specific for each subunit were applied to cryosections by the avidin-biotin-complex method; selected samples were studied by double immunofluorescence microscopy with the Mabs and a polyclonal antiserum to myosin. The authors found that the alpha 1-3,6,v and the beta 1, integrin subunits were detectable in the normal breast parenchyma; myoepithelial cells were consistently more prominently stained than the basolateral aspect of the luminal cells. This immunoprofile was retained, and in cases enhanced through the spectrum of FCD, in benign tumors and in ductal and lobular carcinomas in situ. In most infiltrating ductal carcinomas, integrin staining tended to decrease except for some cases that reacted strongly for the alpha v subunit. Several mucinous carcinomas reacted strongly for alpha 2,3,6,v and beta 4 subunits, and even more so for the alpha 5 subunit that was not found in the normal breast. Subsets of infiltrating lobular carcinomas stained convincingly for alpha 1,3,6,v and beta 1 subunits in delicate but abundant kinetopodia. Our findings indicate that in hyperplasias and in benign tumors integrin expression patterns parallel those of the normal breast, whereas in carcinomas, variations include decrease, enhancement, and emergence of certain subunits that are not in the normal repertory. Alterations of integrin expression parallel phenotypic changes in breast carcinoma cells; they also reflect their disrupted interaction with the similarly disrupted extracellular matrix. Enhancement of certain integrins in some carcinomas may reflect the selection of subpopulations with increased binding capacity which in turn may impact on their invasive and metastatic properties.

Morphometric studies for objective diagnosis of intraductal carcinoma of the breast

In order to obtain objective histologic criteria for distinguishing intraductal carcinomas of the breast from benign intraductal hyperplasia, a morphometric study was carried out on 15 cases of breast carcinoma (5 cases of comedo carcinoma, 5 cribriform carcinoma and 5 papillotubular carcinoma) and 10 benign control lesions (5 papilloma and 5 fibrocystic disease). Morphometric analysis was performed for each group with regard to 1) mean nuclear area, 2) mean nucleolar size, 3) mitotic index, and 4) nuclear count within predefined area (nuclear density) in histologic specimens. The results obtained were as follows: 1) Mean nuclear area for comedo carcinoma was distinctively large. This, together with its coefficiency variance, may be a good indicator for identifying this type of carcinoma. 2) Mean nucleolar size was significantly larger in each carcinoma group than in their benign counterparts. Nucleolar size was therefore considered to be the most reliable parameter for discriminating malignant cells from benign hyperplasia. 3) Mitotic index was relatively high in comedo and papillotubular carcinomas. 4) No difference was seen in nuclear density between the malignant and benign groups. In addition to the major criteria, combined application of these morphometric indicators might also be helpful for practical histologic assessment.

Nuclear morphometry of benign and malignant breast lesions

The mean nuclear area (MNA) of mammary gland epithelium was measured in 403 breast specimens, comprising 239 invasive carcinomas, 49 carcinomas in situ, 45 cases of fibrocystic disease (f.c.d.) with intraductal epithelial hyperplasia, and 60 cases of f.c.d. without intraductal hyperplasia. Normal breast tissue adjacent to other benign or malignant lesions was measured in 170 specimens. Statistical analysis revealed no difference between the MNA of invasive ductal carcinoma and ductal carcinoma in situ. The MNA of lobular and ductal carcinomas were significantly different. Significant differences were also found between ductal carcinoma and the two classes of f.c.d. The MNA of f.c.d. with and without intraductal hyperplasia were also significantly different, the former having the highest MNA. All breast lesions showed MNA significantly higher than that of normal breast epithelium. These findings show that there is a gradual increase in MNA from the baseline value of normal breast epithelium, via fibrocystic disease without and with intraductal proliferation to invasive carcinomas. Measurement of MNA may aid in pinpointing cases of intraductal epithelial hyperplasia with malignant potential.

Glial fibrillary acidic protein immunoreactivity in normal and diseased human breast

Immunostaining for glial fibrillary acidic protein (GFAP) identifies a minor subpopulation of immunoreactive myoepithelial cells in the normal resting human breast. The GFAP-immunoreactive cells also express a panel of myoepithelial cell markers, including cytokeratin 14 (CK 14), vimentin, smooth-muscle-specific actin isoforms, nerve growth factor receptor (NGFR) and common acute lymphoblastic leukaemia antigen (CALLA). The percentage of GFAP-immunoreactive myoepithelial cells is greatly increased in various neoplastic and non-neoplastic diseases of the breast, being highest in adenomyoepitheliomas. Furthermore, in all the instances of fibroadenoma, phyllodes tumour, epitheliosis and gynaecomastia, a variable number of epithelial cells also acquires immunoreactivity for GFAP, vimentin, CK 14, NGFR and, to a lesser extent, for CALLA. Conversely, GFAP immunoreactivity has never been encountered in the malignant cells of the different types of breast carcinoma. These findings suggest that the expression of GFAP might be a (possibly transient) feature of proliferating epithelial and myoepithelial cells in breast diseases other than carcinomas.

Myoepithelial lesions of the breast. Myoepitheliosis, adenomyoepithelioma, and myoepithelial carcinoma

The clinical and pathologic features of 31 breast lesions composed of a prominent proliferation of myoepithelial cells either admixed with epithelial cells or in pure form were studied. The lesions were divided into three categories: myoepitheliosis, adenomyoepithelioma, and malignant myoepithelioma (myoepithelial carcinoma); the latter is the only lesion composed purely of myoepithelial cells. Three multifocal, microscopic lesions located in the peripheral duct system were designated as myoepitheliosis. Twenty-seven solitary, grossly palpable, predominantly centrally located lesions qualified as adenomyoepithelioma. These were further subdivided into spindle-cell, tubular, and lobulated variants. Two lesions in the latter group had a carcinoma arising within them. Only one case, which was characterized by a solitary mass composed of an infiltrative spindle cell proliferation, qualified as malignant myoepithelioma (myoepithelial carcinoma). Two patients with adenomyoepithelioma developed recurrences; one tumor was of the tubular type, the other of the lobulated type. Both of these tumors had irregular margins. One of these patients had two recurrences and is currently well 8.5 years after the initial excision. The second patient developed a recurrence 8 months after initial excision; the recurrence presented as multiple nodules. One of the patients with myoepithelial carcinoma arising in an adenomyoepithelioma also developed a recurrence within 2.3 years. Her initial tumor was located in the axillary tail of the breast, and she had axillary node metastasis at the time of presentation. All remaining patients with follow-up are well without evidence of recurrence up to 17.3 years after the initial diagnosis (average follow-up, 6.1 years); one patient died of unrelated causes.

Proliferation of normal breast epithelial cells as shown by in vivo labeling with bromodeoxyuridine

The proliferative activity of normal acinar and ductal breast epithelial cells was studied by in vivo labeling with 5-bromodeoxyuridine (BrdUrd) in 26 cases with concurrent breast carcinoma. The BrdUrd-labeled cells were recognized in histologic sections of paraffin-embedded tissue, using an anti-BrdUrd antibody and an immunoperoxidase reaction. The percentage of BrdUrd-labeled cells showed great variability for both acinar (0% to 2.66%; mean, 0.70%; standard deviation [SD], 0.80%) and ductal cells (0% to 1.99%; mean, 0.51%; SD, 0.57%). The fraction of proliferating epithelial cells declined with the age of the patients and was significantly higher in premenopausal women (1.16% +/- 0.85% for acinar and 0.94% +/- 0.60% for ductal cells) as compared with the postmenopausal women (0.27% +/- 0.46% for acinar and 0.17% +/- 0.22% for ductal cells), P less than 0.01 for acinar and P less than 0.001 for ductal cells, respectively. In some patients, great variability in distribution of proliferating acinar and ductal cells among different lobules and ducts was observed. No difference was found in the number of proliferating acinar and ductal cells situated near or far from their corresponding tumors. No correlation was seen between cell proliferation of normal acinar or ductal cells and cell proliferation of the respective tumors.

Morphometric evaluation of collagen fibril dimensions in expanded human breast skin

A great innovation in plastic surgery in recent years has been skin expansion, which has provided the discipline with new possibilities for skin reconstruction. At present, little is known about the biology of skin expansion although it is clear that cell proliferation occurs both in the epidermis and the dermis. During previous morphological investigations of skin under expansion we recorded a number of signs comparable with those seen in wound healing. In the present study, the collagen fibril diameter of of skin before and under expansion has been recorded using an IBAS computer-based morphometric system. Preferentially, we have studied the papillary dermis where the most conspicuous morphological events occur.

Intranuclear helioid inclusions in mammary intraductal hyperplasias

Intranuclear helioid bodies were identified by light microscopy in eight cases of mammary intraductal hyperplasia, only one of which was atypical. These structures appear as round, intranuclear eosinophilic bodies on light microscopic examination. When prominent, they may be and have been mistaken for viral inclusions. Ultrastructural analysis of these inclusions shows a single-membrane-bound structure containing a laminated or homogeneously electron-dense core with a corona of radiating filaments. In the first and only previous report of this structure in the breast, helioid bodies were identified incidentally during an ultrastructural analysis of a breast adenoma, but the light microscopic counterpart of this structure was not described or illustrated. In view of the similarity of the laminated inclusions to psammoma bodies, the possibility that helioid bodies serve as a nidus for development of microcalcification in the breast was considered. Actual microcalcification was not evident in the vicinity of any of these inclusions, however, and there was no evidence of calcification in these structures on von Kossa's stain for calcium.