Differential diagnosis of benign epithelial proliferations and carcinomas of the breast using antibodies to cytokeratins

Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases

Cytokeratin 7 (CK 7) and cytokeratin 20 (CK 20) are low molecular weight cytokeratins. Their anatomic distribution is generally restricted to epithelia and their neoplasms. We surveyed 435 epithelial neoplasms from various organ systems by immunohistochemistry using CK 7 and CK 20 monoclonal antibodies. Expression of CK 7 was seen in the majority of cases of carcinoma, with the exception of those carcinomas arising from the colon, prostate, kidney, and thymus; carcinoid tumors of the lung and gastrointestinal tract origin; and Merkel cell tumor of the skin. The majority of cases of squamous cell carcinoma of various origins were negative for CK 7, except cervical squamous cell carcinoma, in which 87% of cases were positive. Approximately two thirds of cases of malignant mesothelioma were CK 7-positive. CK 20 positivity was seen in virtually all cases of colorectal carcinomas and Merkel cell tumors. CK 20-positive staining was also observed in cases of pancreatic carcinomas (62%), gastric carcinoma (50%), cholangiocarcinomas (43%), and transitional cell carcinomas (29%). The expression of CK 20 was virtually absent in carcinomas from other organ systems and in malignant mesothelioma. CK 7- and CK 20-negative epithelial neoplasms included adrenal cortical carcinoma, germ cell tumor, prostate carcinoma, renal cell carcinoma, and hepatocellular carcinoma.

The cytokeratin profile of medullary carcinoma of the breast

AIMS

The cytokeratin (CK) phenotype and vimentin expression of 31 medullary carcinomas was studied using commercially available antibodies on archived material. Comparing the phenotype of typical and atypical tumours and the phenotype of metastases, the biological significance of cytokeratin and vimentin expression in medullary carcinomas of the breast was determined.

METHODS AND RESULTS

Antibodies to CK4, CK5 and 6, CK7, CK14, CK8 and 18, CK19, CK20 and to vimentin were used. All the typical and atypical medullary carcinomas and the metastases (10 cases) stained negatively for CK4 and positively for CK8-18 (CAM5.2). Almost all the tumours were CK7 and CK19 positive and CK20 negative. Twelve per cent of the tumours contained CK14. Twenty-five per cent of the typical, 43% of the atypical and 20% of the metastatic medullary carcinomas showed CK5-6 positivity. No association between the cytokeratin-vimentin profile of the tumours and axillary node metastases, tumour size or oestrogen receptor status was found but instability of CK expression was demonstrated by comparing the primary tumours with their metastases.

CONCLUSIONS

: Medullary carcinomas of the breast express all the glandular type CKs including CK19 and additionally a proportion of the tumours expresses some of the CKs typical for myoepithelial cells. There was no correlation with prognostic factors.

Use of keratin 35betaE12 as an adjunct in the diagnosis of mammary intraepithelial neoplasia-ductal type--benign and malignant intraductal proliferations

A variety of studies have investigated the role of low molecular weight (LMW) and high molecular weight (HMW) cytokeratin (CK) expression in the normal breast and invasive breast carcinomas. A few studies with small numbers of cases have addressed this issue in intraductal proliferations of the breast. This study investigates the expression of these CKs in a large series of ductal intraepithelial neoplasias of the breast. We examined 150 ductal carcinomas in situ (DCIS), 35 cases of intraductal hyperplasia (IDH), and 15 cases of atypical intraductal hyperplasia (AIDH). Immunohistochemistry was performed using monoclonal antibodies against CK-34betaE12 (HMW CK), CK-8, and CK-19 (LMW CK) on formalin-fixed, paraffin-embedded tissue. The intensity (0, +1, +2, +3) and percentage of positive intraductal cells (0-100%) were multiplied to obtain a score from 0 to 300. The immunoprofiles of IDH, AIDH, and DCIS were categorized into four groups showing negative or low (0-60), moderate (61-100), high (101-200), and very high (201-300) scores. All cases of IDH showed an intensely positive reaction (high to very high scores) for CK-34betaE12. In contrast, 90% of the DCIS showed a negative or only focal and weak reaction (negative or low score) for this antigen. The remaining 10% of DCIS showed a positive immunoreaction for CK-34betaE12 with moderate to high scores. All cases of florid IDH and 96% of cases of DCIS expressed CK-8 intensely with high to very high scores. Although CK-19 was strongly expressed in 97% of cases of IDH (high to very high scores), a very high score was also found in 80% of cases of DCIS that were positive for CK-19. Of the 15 AIDHs, 80% had a negative or only focal reaction (negative or low score) for CK-34betaE12 and the remaining 20% had a moderate to high score for this antigen. Although CK-8 was strongly positive in 87% of cases of AIDH (high to very high scores), only 53.5% of AIDHs showed intense positivity for CK-19. The present study clearly shows that the immunoprofile of IDH is different from DCIS as far as HMW CK is concerned. Although florid IDH is characterized by a diffuse and intense immunoreaction for HMW CK, the lack of or only weak positivity for HMW CK (CK-34betaE12) is, in most cases, a hallmark of ductal carcinoma in situ. The immunoprofile of AIDH is very similar to that of DCIS. The expression of CK-8 and CK-19 is not useful in separating the various categories of ductal intraepithelial proliferations of the breast. We recommend the use of CK-34betaE12 as an adjunct in the diagnosis of a variety of problematic intraductal proliferations of the breast.

Differentiation pathways in primary invasive breast carcinoma as suggested by intermediate filament and biopathological marker expression

The expression of intermediate filament proteins (IFPs) in 65 primary breast carcinomas was analysed by a panel of specific antibodies. Results were integrated with the oestrogen and progesterone receptor (ER and PGR) status, Ki-67 marking, and epidermal growth factor receptor (EGFr) expression. Invasive breast carcinomas could be divided into three main groups: group 1 revealed positivity only for 'simple epithelial' cytokeratins (CKs 7, 8, 18, and 19); group 2 also stained with the antibodies K8.12 and 34 beta E12; while group 3 showed co-expression of CKs 14 and 17, vimentin, and alpha-smooth muscle actin. Group 3 consistently comprised tumours with the highest Ki-67 levels, EGFr positivity, and ER-PGR negative status. On the other hand, groups 1 and 2 usually exhibited a positive hormonal status, lower proliferative activity, and EGFr negativity. The results of this study indicate that the determination of IFPs can significantly contribute to the identification of groups of patients with different biopathological settings and possibly different clinical behaviour.

Application of immunostaining for muscle specific actin in detection of myoepithelial cells in breast fine-needle aspirates

Myoepithelial cells play an important role in the interpretation of breast fine-needle aspiration biopsy, since these cells are believed to be a component of a benign process in breast lesions. Myoepithelial cells are usually easy to recognize, however, other cells can morphologically simulate myoepithelial cells and make the distinction difficult. To assess the feasibility of immunostaining as an adjunct to identify myoepithelial cells, we have used immunocytochemistry using monoclonal antibody against muscle specific actin (MSA) in our breast fine-needle aspirates. Herein, we report our experience in immunocytochemical detection of myoepithelial cells using labeled Streptavidin Biotin Detection System on destained Papanicolaou stained smears and cell block preparations obtained from breast aspirates.

Detection of intraoperative tumor cell dissemination in patients with breast cancer by use of reverse transcription and polymerase chain reaction

BACKGROUND

Animal studies have shown that malignant cells are shed into the blood stream during surgical resection of a primary tumor and that this may enhance the development of metastases. The evidence for tumor cell dissemination during surgical manipulation of human cancer is unclear. We have applied the technique of reverse transcription and polymerase chain reaction to detect circulating tumor cells in peripheral venous blood of patients with breast cancer perioperatively.

METHODS

To target breast-specific gene transcription complementary DNA was prepared by reverse transcription of blood messenger RNA with oligonucleotide primers unique to CK18 and DF3 antigens. Preliminary assessment of specificity showed that the DF3 antigen was more suitable than CK18 for the purpose of this study. Assessment of sensitivity showed that as few as 10 tumor cells per 5 ml blood could be identified by this method. Peripheral blood samples were obtained by venepuncture from patients before, during, and 24 hours after breast surgery (nine malignant and three benign).

RESULTS

In the group of patients with malignant disease, tumor cells were detected in one patient before operation and four patients during operation. No tumor cells were detected in the postoperative samples nor in any of the samples of patients with benign disease.

CONCLUSIONS

These findings suggest that tumor manipulation during operation encourages tumor cell dissemination.

Epithelial Proliferative Lesions and Carcinomas in Fibroadenomas of the Breast

Sixteen cases of fibroadenomas with epithelial proliferative lesions (EP lesions) with histologic features resembling those of epithelial hyperplasia, sclerosing adenosis, and microglandular adenosis, and four cases of carcinomas in fibroadenomas (CA lesions) were studied histopathologically and immunohistochemically. The CA lesions included one intraductal carcinoma, two invasive ductal carcinomas, and one lobular carcinoma in situ. The histologic features of the EP lesions and CA lesions were fundamentally the same as those of carcinomas commonly observed in the mammary gland. Immunohistochemically, smooth muscle actin was useful in the detection of myoepithelial cells, particularly in EP lesions of the adenosis type (sclerosing adenosis or microglandular adenosis), and in distinguishing carcinoma. The differences between EP lesions and CA lesions of sites of immunoreactivity to CA15-3, CEA, and EMA were also helpful for differential diagnosis.

Immunohistochemical demonstration of metallothionein in normal human breast tissue and benign and malignant breast lesions

Metallothioneins (MTs) are a set of low molecular weight proteins with a high binding affinity to metal ions. MT over-expression has been recently demonstrated in invasive ductal carcinoma of the breast with poor clinical prognosis. In the present study, MTs have been immunohistochemically investigated in normal human breast tissue and a variety of benign, pre-invasive, and malignant breast lesions. In normal breast tissue, MTs were present in myoepithelial cells whereas the vast majority of luminal cells were MT negative. In lesions without increased cancer risk (adenosis and scleradenosis), MT was only immunolocalized in myoepithelial cells. In papillomas, MT was also found exclusively in myoepithelial cells. In most cases of epitheliosis, both the luminal and myoepithelial cells expressed MT. Atypical lobular hyperplasia, lobular carcinoma in situ, and 13/15 invasive lobular carcinomas showed no MT over-expression. The two invasive lobular carcinomas with MT over-expression were classified as pleomorphic lobular carcinomas with apocrine differentiation. In contrast to lobular cancerization, 12/24 ductal in situ carcinomas and 9/20 invasive ductal carcinomas showed MT over-expression. In situ components found within invasive ductal carcinomas usually reflected the MT status of their invasive counterpart. It is concluded from our immunohistochemical results that breast carcinoma cases with MT overexpression arise from lesions which also show MT overexpression. Thus MT expression in carcinomas may be regarded as a genuine feature of the tumour cells and seems not to be related to endogenous or exogenous factors known to induce MT synthesis.

Immunoperoxidase localization and denovo biosynthesis of a 10.5-kDa inhibin in benign and malignant conditions of human breast

Using immunocytochemistry, we report the occurrence of a 10.5-kDa inhibin in human breast tissue specimens obtained from normal, fibroadenoma and adenocarcinoma cases. The immunostaining for inhibin was confined to the cytoplasm of the epithelium and myoepithelium cells. Expression of inhibin increased in following order: normal (1+); adenocarcinoma and lobular carcinoma in situ (2+) and fibroadenoma (4+). Breast explants has the ability of denovo biosynthesis of inhibin in vitro. In view of the growth modulating regulatory properties of 10.5 kDa inhibin, our findings are suggestive of the potential role of inhibin in breast pathology.

Subtypes of non-transformed human mammary epithelial cells cultured in vitro: histo-blood group antigen H type 2 defines basal cell-derived cells

Normal (non-transformed) human mammary epithelial cell lines derived from reduction mammoplasties were analyzed by immunocytochemistry with more than 80 monoclonal antibodies (mAbs) and other specific reagents to tissue-specific and developmentally regulated antigens at different passage levels. A subpopulation of poorly differentiated, proliferating epithelial cells, corresponding to the 'selected' cell type of late passages, is shown to be characterized by a new marker, the histo-blood group antigen H type 2, probably carried on a membrane-bound glycolipid. These cells also express a number of other onco-developmental carbohydrate antigens [Le(y), Le(x), sialosyl-Le(a), precursor of Thomsen Friedenreich antigen (Tn), but not Thomsen-Friedenreich antigen and sialosyl-Tn]. Their cytokeratin (CK) phenotype, as assessed by reactivity with monospecific mAbs and two-dimensional gel electrophoresis, is CK 5, 6, 14 and 17, with CK 19 being consistently absent, and varying minor amounts of CK 7, 8 and 18, as well as 15 and 16. The reactivity of these cells with a panel of 11 mAbs specific for CK 18 varies considerably even after cloning, indicating heterogeneity of epitope expression or accessibility. Our data strongly suggest that the H type 2+ cells develop from the basal cell layer of the mammary gland.

Squamous cell carcinomas. An immunohistochemical study of cytokeratins and involucrin in primary and metastatic tumours

The expression of cytokeratins (CK) 1, 4, 5/6, 8, 13, 18, 19 and 20 and involucrin in 42 cases of squamous cell carcinomas from various locations was examined. The tumours expressed CK5/6 in 55%, CK8 in 76%, CK13 in 43% and CK19 in 95% of cases. The CK5/6-positive primary tumours were from uterine cervix, head and neck, lung, skin, oesophagus and urinary bladder, and the CK13-positive primary tumours were from uterine cervix, lung and vulva. Metastatic squamous cell carcinomas from head and neck more frequently expressed CK5/6 and 13, 7/7 (100%) and 6/7 (86%) compared with 3/5 (60%) and 0/5 (0%) in the primary squamous cell carcinomas. Few cases were CK1, CK4 and CK18 immunoreactive. CK20 immunoreactivity was not observed. Involucrin was expressed in 71% of tumours, and most of the involucrin-positive cells were located at the central parts of tumour cell clusters except for one case in which the peripheral cells around tumour cell clusters were positive. Thus, expression of the so-called simple epithelial markers CK8 and CK19 occurs in the majority of squamous cell carcinomas. The absence of CK20 immunoreactivity may be helpful in differential diagnosis.

Ductal adenoma of the breast. An immunohistochemical study of five cases

The immunohistochemical features of 5 ductal adenomas of the breast were investigated. The tumours were composed by tubular glands lined by cells with both luminal and basal/myoepithelial immunophenotypes. Tubules were encircled by an intact basement membrane as demonstrated by staining for laminin and type IV collagen. Areas of dense fibrosis, a usual finding in these lesions, stained for fibronectin, type III collagen and contained vimentin and actin positive spindle cells, consistent with myofibroblasts. These observations confirm a double epithelial and myoepithelial differentiation in these lesions and seem to support the suggestion that ductal adenomas result from sclerosis of ductal papillomas.

The human gene encoding cytokeratin 20 and its expression during fetal development and in gastrointestinal carcinomas

The differentiation of the predominant cell types of the mucosal epithelium of the mammalian gastrointestinal tract is characterized by increasing amounts of an intermediate-sized filament (IF) protein designated cytokeratin (CK) 20 which is a major cellular protein of mature enterocytes and goblet cells. Here we report the isolation of the human gene encoding CK 20, its complete nucleotide sequence and the amino acid sequence deduced therefrom that identifies this polypeptide (mol. wt. 48553) as a member of the type I-CK subfamily. Remarkable, however, is the comparably great sequence divergence of CK 20 from all other known type I-CKs, with only 58% identical amino acids in the conserved alpha-helical 'rod' domain of CK 20 and, e.g. CK 14. Using riboprobes corresponding to exon 6 of the gene in Northern blot and ribonuclease protection assays, we show that the approximately 1.75 kb mRNA encoding CK 20 is specifically produced in cells of the intestinal and gastric mucosa, including tumors and cell lines derived therefrom. The appearance of CK 20-positive cells in human embryonic and fetal development and in adult tissues has been studied using immunohistochemistry with CK 20-specific antibodies. CK 20 synthesis has first been recognized at embryonic week 8 in individual 'converted' simple epithelial cells of the developing intestinal mucosa. In later fetal stages, CK 20 synthesis extends over most goblet cells and a variable number of villus enterocytes. The distribution of CK 20-positive cells in the developing gastric and intestinal mucosa is similar to--but not identical with--the pattern in the adult intestine in which all enterocytes and goblet cells as well as certain 'low-differentiated' columnar cells contain CK 20, whereas the neuroendocrine ('enterochromaffin') and Paneth cells are negative. In gastrointestinal carcinomas similarly examined, CK 20 has been detected in almost all cases (50/52) of colorectal adenocarcinomas, including all grades of differentiation and malignancy and also metastatic tumors, whereas CK 20 immunostaining in gastric carcinomas has been found less consistent and more heterogeneous. The possible biological meaning of the specific expression of the CK 20 gene in certain cells of the gastrointestinal tract and carcinomas derived therefrom and the regulatory mechanisms involved in the integration of the protein in the IF cytoskeleton are discussed.

Involucrin expression in breast carcinomas: an immunohistochemical study

The expression of involucrin, a structural component of the envelope of mature squamous epithelium, was studied in 166 paraffin-embedded breast carcinomas. In 41 cases (24.7%) involucrin-positive, light microscopically non squamous tumour cells were detected. The number of involucrin-positive tumour cells varied considerably from case to case. For further characterization, involucrin-positive cases were studied using monoclonal antibodies to various cytokeratins (PKK1, EAB 903, EAB 904) and, in selected cases, double immunostaining with antibodies to cytokeratins and involucrin were performed. Coexpression of involucrin and cytokeratins demonstrated by PKK1 was seen in all tumour cells, whereas coexpression of involucrin and cytokeratins detected by EAB 904 was only seen in single and scattered cells in a few cases. Cytokeratins detected by EAB 903 were not coexpressed with involucrin in our cases. Our results indicate heterogeneity of cytokeratins in breast carcinomas and suggest a dissociation in the regulation of involucrin and cytokeratin expression.

Immunohistochemical identification of myoepithelial, epithelial, and connective tissue cells in canine mammary tumors

Fifty-eight formalin-fixed paraffin-embedded canine mammary tumors, 19 malignant and 39 benign, were used in this study. Tumors were obtained from dogs submitted for surgical resection of lesions at private veterinary practices in Brussels or from the surgery unit of the Faculty of Veterinary Medicine, University of Liège. Immunohistochemical evaluation was performed, using monoclonal antibodies directed against keratins 8-18 and 19, vimentin, desmin, and alpha-actin and polyclonal antibodies directed against high-molecular-weight keratins and S-100 protein. The main cell types, epithelial, myoepithelial, and connective, were identified, and myoepithelial cells represented the major component of most tumors, both benign and malignant. Myoepithelial cells had five patterns: resting and proliferative suprabasal cells, spindle and star-shaped interstitial cells, and cartilage. Reactivity to keratin 19, vimentin, alpha-actin, and S-100 protein suggested a progressive transformation from resting cells to cartilage. Epithelial cell reactivities were limited to keratins; only keratinized cells were positive for polyclonal keratins. Myofibroblasts were positive for both vimentin and alpha-actin, and connective tissue cells were positive for vimentin. Myoepithelial cells appeared to be the major component of carcinomas, justifying reevaluation and simplification of histomorphologic classifications, with a "pleomorphic carcinoma" group including all carcinomas except squamous, mucinous, and comedo carcinomas. Immunohistochemical evaluation, in addition to routine hematoxylin and eosin histopathologic evaluation is recommended for precise classification of canine mammary tumors.

Patterns of cytokeratin expression by neoplastic and non-neoplastic epithelium

Eighty-one epithelial lesions were studied immunohistologically for cytokeratin protein expression using three anticytokeratins CAM 5.2, NCL5D3 and RCK102. Consistent differences were noted between squamous and glandular neoplasms. Squamous and cutaneous carcinomas were found to preferentially express higher molecular weight cytokeratins than adenocarcinomas. In addition, tumours of similar morphology from different sites showed differences in expression of these markers. Differences in pattern were also found between benign and malignant lesions in the case of liver and urinary bladder. Thus the value of cytokeratin profile analysis in characterisation of epithelial neoplasms is confirmed and may be useful in distinguishing benign from malignant tumours in some instances.

Myoepithelial and basement membrane antigens in benign and malignant human breast tumors

Serial cryostat sections of 160 human breast lesions and of 9 lymph-node metastases were studied by indirect immunofluorescence. We used monoclonal antibodies (MAbs) to lining-epithelium-specific keratin 8 and to myoepithelium-specific keratin 17 in combination with polyclonal and monoclonal antibodies to major basement membrane components, laminin, collagen type IV, entactin/nidogen, and large heparan sulfate proteoglycan (perlecan) core protein. Continuous basement membranes adjacent to a basal layer of keratin-17-positive myoepithelial cells were typical for normal, benign and in situ carcinomatous structures. In invasive and metastatic structures, always formed by keratin-8-positive tumor cells, basement membranes were found only rarely and with conspicuous fragmentations. This lack of basement membranes correlated with loss of myoepithelium identified by staining for keratin 17. In comedo structures of invasive ductal carcinomas and in papillary carcinomas, fibrovascular complexes with numerous blood vessels and deposition of basement membrane material were often seen in the stroma. Immunomorphological analysis of 41 cases of doubtful diagnosis at intra-operative biopsy was also performed. A combination of MAbs to keratins 8 and 17, and to basement membrane components, made it possible to distinguish between morphologically similar benign and malignant proliferations and to detect single-cell invasion of the stroma. This combination of antibodies may be recommended as an auxiliary immunomorphological tool for differential diagnosis of intra-operative breast biopsies in dubious cases.

Immunohistochemical evaluation of the cytoarchitecture of benign and malignant breast lesions

Fifty-three breast lesions, which had been fixed in formalin and embedded in paraffin, were immunohistochemically analyzed with monoclonal antibodies to cytokeratin subtypes 1, 5, 10, 14 (34BE12), muscle-specific actins (HHF35) and antiserum to S100 protein, all of which have been used as markers for myoepithelial cells. With these antibodies, a continuous myoepithelial cell layer could generally be seen around the benign ducts and acini. In in situ carcinomas, such a layer could still be observed, though it was usually discontinuous and sometimes absent. In infiltrating carcinomas, no myoepithelial cell layer could be observed. In intraductal hyperplasias, scattered HHF35, 34BE12 and S100-positive cells could be seen amongst the proliferating intraductal cells. In in situ and infiltrating carcinomas, however, such cells could also be observed. This was seen especially with antibodies 34BE12 and S100, and to a lesser extent also with HHF35. Morphologically these cells seemed to belong to the malignant cell population. Although myoepithelial cell preservation is an important morphological parameter in the histological evaluation of breast lesions, the results suggest that the myoepithelial cell markers 34BE12, HHF35 and S100 cannot be used in the differential diagnosis between benign and malignant breast lesions in a straightforward manner. This is because in situ carcinomas have a more or less preserved myoepithelial cell layer, and because many infiltrating and in situ carcinomas contain a subpopulation of neoplastic cells expressing these markers, possibly signifying myoepithelial cell differentiation.

Histopathology of myoepithelial (basocellular) hyperplasias in adenosis and epitheliosis of the breast demonstrated by the reactivity of cytokeratins and S100 protein. An analysis of heterogenic cell proliferations in 90 cases of benign and malignant breast diseases

This study on the different types of epithelial hyperplasia in fibrocystic disease was inspired by the observation of myoepithelial (basocellular) hyperplasia identified by strong expression of S100 protein and a weak reaction with antibodies against cytokeratin (KL1) in cells forming solid and acinar buds. The cells do not contain immunohistochemically detectable actin or desmin. Glandular transformation and proliferation give rise to basocellular circumductal adenosis. Normal breast tissue, 51 cases of fibrocystic disease with mild, florid and atypical hyperplasias, 7 fibroadenomas and 20 cases of carcinoma in situ were studied and a semiquantitative analysis revealed basal buds and adenosis in less than 40% of cases of mild hyperplasia and up to 73% in florid hyperplasia. Epitheliosis is characterized by a heterogeneous cell pattern with cells positive for S100 protein in 30-60%, but in small ducts up to 100% with an immediate connection to the basal cell layer were positive. Carcinoma in situ contained very rare tumour cells positive for S100 protein. The cells expressing S100 protein in terminal ducts, in adenosis and epitheliosis showed only some of the characteristics of myoepithelial cells, since they lack immunoreactivity with antibodies against actin. These basal clear cells are interpreted as transitional or indeterminate cells with features of myoepithelial precursor cells, but with the ability to develop basocellular nodular and glandular hyperplasia in the ductulo-lobular units in cases of adenosis and juvenile fibroadenoma.

An immunohistochemical study of the breast using antibodies to basal and luminal keratins, alpha-smooth muscle actin, vimentin, collagen IV and laminin. Part I: Normal breast and benign proliferative lesions

The distribution of simple epithelial (K8/18/19) and basal (myoepithelial) (K5/14) keratins, alpha-smooth-muscle actin, vimentin, collagen IV and laminin in normal mammary glands and in benign proliferative lesions was studied using monoclonal antibodies (mAbs). These antibodies (Abs) identified myoepithelial cells and luminal cells specifically. In lesions with adenosis and papillomas, the two-layered formation resembled that of normal glands with a purely myoepithelial-epithelial differentiation. In scleradenotic lesions, the main cell was of myoepithelial immunophenotype with intermixed trabecular-tubular proliferations of simple-type epithelium. The sclerosis seems to be the result of an irregular basal lamina synthesis by the myoepithelial cells. In contrast to these lesions, epitheliosis represents a purely intraluminal cell proliferation of clearly simple epithelial immunophenotype and of cells with a basal keratin phenotype, lacking myoepithelial differentiation antigen actin. The basal keratin type epithelium may represent post-stem or intermediate cells developing into luminal epithelium. Epitheliosis appears to be a purely epithelial hyperplasia with striking similarity to the regeneration of normal breast epithelium. The different proliferative patterns may give an explanation for differences in potential cancer risks of patients with these lesions.

An immunohistochemical study of the breast using antibodies to basal and luminal keratins, alpha-smooth muscle actin, vimentin, collagen IV and laminin. Part II: Epitheliosis and ductal carcinoma in situ

A detailed immunohistochemical study has been carried out on 63 breast lesions with epitheliosis, ductal carcinoma in situ and clinging carcinoma (lobular cancerization), using antibodies directed against keratins 5/14 and 14, 15, 16, 18, 19, vimentin, smooth muscle actin, collagen IV and laminin. The results have shown that epitheliosis on the one hand and ductal in situ and clinging carcinoma on the other are immunohistochemically different epithelial lesions. Epitheliosis appears to be epithelial hyperplasia with keratin 5/14 and keratin 14, 15, 16, 18, 19-positive cells. Compared to epitheliotic cells tumor cells of clinging carcinoma, lobular cancerization and ductal carcinoma in situ expressed only luminal keratins 14, 15, 16, 18, 19 in 85% of the cases studied; whereas in 15% there was a basal keratin expression. From our results we conclude that the clinging carcinoma (lobular cancerization) represents the initial morphological step in the development of ductal carcinoma in situ and thus may be interpreted as a minimal ductal neoplasia. With the immunohistochemical demonstration of basal and luminal keratins it may be possible in individual cases to differentiate between benign and malignant in situ lesions of the breast.

Characterization of four in vitro established canine mammary carcinoma and one atypical benign mixed tumor cell lines

Five spontaneous canine mammary tumors were cultured in vitro and cell lines were established. The tumors included three frozen carcinomas, fine-needle aspirate from one fresh carcinoma, and one fresh atypical benign mixed tumor. The cell lines have so far been cultured for about 2 yr and passaged between 45 and 200 times. The cell lines expressed different types of intermediate filaments, including a heterogenous pattern. In some cases no intermediate filaments were expressed. Ultrastructure studies showed epithelial cells and cells intermediate between epithelial and myoepithelial types. Retrovirus associated A-particles were found in two carcinomas. The mixed mammary tumor cell line formed ductlike structures in collagen substrate. The cell lines grew when inoculated s.c. into male nude mice. Two carcinomas caused lymph node metastases in two mice and another carcinoma single lung metastases in one tested mouse. DNA hypodiploidy, studied by flow cytometry, in one of the primary carcinoma was retained in vitro, and this cell line showed polyploidy during later passages. The other cell lines had a more unstable DNA profile, although a tendency for polyploidy was found. These findings were also illustrated in chromosome studies.

Complexity of expression of intermediate filament proteins, including glial filament protein, in endometrial and ovarian adenocarcinomas

The expression patterns of intermediate filament proteins of primary and metastatic endometrial (n = 18) and ovarian (n = 24) adenocarcinomas were analyzed by immunocytochemistry using a panel of specific antibodies and by gel electrophoresis of cytoskeletal preparations, followed by immunoblotting. All cells of all endometrial adenocarcinomas studied contained the "simple epithelial"-type cytokeratins (CKs) 8, 18, and (mostly) 19, with variable numbers of cells also positive for CK 7 and vimentin. In addition, most of these tumors contained individual cells or groups of cells that were positive for the stratification-related CKs 4, 5, 6, 13, 14, and 17. The latter CKs were often associated with squamous cell foci, but were also found in some single (nonsquamous) tumor cells, indicative of early stages of squamous cell differentiation. Ovarian carcinomas of various histologic types and grades contained predominantly CKs 7, 8, 18, and 19. Serous, endometrioid, and anaplastic tumors, but not mucinous and clear cell tumors, also contained minor amounts of stratification-related CKs in variable combinations, mostly including CK 4. In all tumor types except mucinous tumors, vimentin was consistently detected in variable proportions of tumor cells which, however, were rather low in anaplastic carcinomas. Surprisingly, glial filament protein was detected in a minor proportion (< or = 20%) of tumor cells in seven of 14 serous and endometrioid ovarian carcinomas and in three of 18 endometrial carcinomas. These different intermediate filament expression patterns of müllerian duct-type carcinomas, only partly related to the morphologic appearance of the specific type of tumor, might reflect the multipotentiality of differentiation of müllerian duct-derived epithelia. Cytoskeletal features of potential diagnostic value, especially in metastatic carcinomas, are discussed.

Myoepitheliomas in inbred laboratory mice

Myoepitheliomas are subcutaneous tumors that arise from myoepithelial cells of various exocrine glands. In a retrospective study of 142 tumors observed over a period of 3 years, myoepitheliomas occurred spontaneously in A/HeJ, A/J, BALB/cJ, BALB/cByJ, LLC.A/Ckc, and NOD/Lt inbred strains of mice. Tumors presented primarily in the subcutaneous tissues of the ventral neck (74% of the myoepitheliomas evaluated) but were observed in several other subcutaneous locations, including the head, perineum, and ventral abdomen. These areas were adjacent to salivary, mammary, clitoral, preputial, and Harderian glands. Forty myoepitheliomas were tested by the avidin-biotin complex technique with a panel of antisera specific for mouse keratins, intermediate filaments, and other cytoskeletal proteins to determine the cell type from which this neoplasm originated. Antibodies directed against the specific mouse keratins K5, K6, and K14, and a broadly cross-reactive cytokeratin antibody stained acinar and ductal myoepithelial cells in normal mammary, salivary, and Harderian glands, and neoplastic cells in all cases. Antisera directed against a smooth muscle actin (anti-alpha-sm-1) stained acinar myoepithelial cells of the glands and vascular smooth muscle but neither ductular myoepithelial cells nor tumor cells. This supports the notion that these tumors originate from extraglandular ductular myoepithelial cells. Southern blots, prepared from DNA extracted from nine myoepitheliomas, did not show restriction fragment length polymorphisms when mouse mammary tumor virus (MMTV) cDNA or Int-1 genomic DNA probes were used; this implies that a retrovirus is not the etiologic agent.

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.

Keratin expression in the normal breast and in breast carcinoma

The immunohistochemical reactivities of 69 cases of breast carcinoma were examined on methacarn-fixed, paraffin-embedded sections using eight different monoclonal antibodies which recognize one or a few keratin polypeptides. In the normal breast, the monoclonal antibodies RPN1162, RPN1165 and AE1 stained almost all the luminal cells but not the basal (myoepithelial) cells. The monoclonal antibodies 35BH11, M20, CK5 and CK8.12 stained only a subset of the luminal cells. In contrast, 312C8-1 stained basal cells but not luminal cells. All the tumour specimens reacted with AE1, while over 80% of them also reacted with 35BH11 (57/69), CK5 (57/69) and RPN1165 (55/69); 30% reacted with CK8.12 (21/69) and 16% with RPN1162 (11/69). Basal cell-specific keratin, as defined by 312C8-1, was detected in only 1% of cases (1/69). Monoclonal antibodies to different keratin polypeptides may be of use in the characterization and subdivision of breast cancer.

Monoclonal antibodies for radioimmunoscintigraphy of breast cancer

Breast cancer is the leading cause of cancer deaths among females, and it is estimated that each year, one in ten American women will be newly diagnosed as having the disease. It is therefore not surprising, that a great deal of effort has been made to better understand the biology of breast cancer, and that investigators keep up the search for new tools to better characterize, diagnose and treat these tumours. In this regard, the introduction of the hybridoma technique in 1975 by Kohler and Milstein has lead to an extensive work in the characterization of monoclonal and polyclonal antibodies against breast cancers. A large number of antibodies has been raised to different epitopes present in normal and neoplastic breast tissue; but unfortunately we have yet to find a highly sensitive and specific monoclonal antibody for breast cancer that can successfully be used for scintigraphic detection of nodal metastases and for radioimmunotherapy treatment of this disease. As possible radioimmunodiagnostics, antibodies are known which react with the following antigens: (1) cytoskeletal proteins (2) breast cell products (3) steroid receptors (4) putative tumor-associated antigens (5) oncogene products (6) pregnancy-related products (7) basement membrane antigens (8) degradative enzymes (9) cell receptors for extracellular matrix molecules (10) multidrug resistance gene product (p-glycoprotein) (11) proliferative markers.

Biological response modifiers in the management of patients with breast cancer

Despite impressive progress in understanding the biology of breast cancer, mechanisms of host defense, and the pathophysiology of the metastatic process, this burgeoning fact bank has made little impact on the management of patients with breast cancer. There are many interesting ideas for improved diagnosis and therapy in various stages of development, but few have actually translated into improved survival of patients with breast cancer. Potentially useful biological agents include cytokines, monoclonal antibodies, immunotoxins, vaccines, and adoptive cellular therapies. Therapies targetting growth factor receptors and the cellular machinery required for metastasis may become useful, especially when used in combination with other cytotoxic agents. Colony-stimulating factors may allow a test of the hypothesis that augmented dose-intensity of cytotoxic chemotherapy will cure more patients. Though we are not yet sure precisely how to use all of these new tools, there can be little doubt that their application will make a significant impact on the management of patients with breast cancer and other malignancies in the next decade.

Antigenic profile of mammary fibroadenoma and cystosarcoma phyllodes. A study using antibodies to estrogen- and progesterone receptors and to a panel of cell surface molecules

Using serial frozen sections, monoclonal antibodies and an indirect immunoperoxidase method, 13 fibroadenomas (FA) and 3 cystosarcomas phyllodes (CSP) were analyzed for the expression of Egp34, HEA319-antigen, leucocyte differentiation antigens CD10, CD30, CD57, CD72, CDw75, and CD77, epidermal growth factor receptor (EGFR), estrogen (ER) and progesterone receptor (PR), and transferrin receptor (CD71). Egp34, CDw75, HEA319 antigen, CD10, and CD30 turned out to be consistently expressed in different cell types constituting FA and CSP and revealed that in malignant CSP the myoepithelial compartment acquires the ability to invade the stroma. Phenomenologically, the variable mode of expression of CD57 in myoepithelial cells, of CD77 in ductal epithelium, and of CD72 in both epithelial and stromal cells is suggestive for reflecting differences in their functional state but cannot be further interpreted at present. Expression of PR and ER was restricted to duct cells and was relatively independent, non-systematical. However, expression of ER and EGFR was inverse. This was also true for EGFR and CD71 in both duct cells and myoepithelial cells of FA. In contrast, stromal cells of FA were able to co-express EGFR and CD71 in the absence of PR and ER. This suggests a hormone-independent stimulation of the stromal cell compartment, possibly leading to local proliferation as the primary event in tumorigenesis of FA. In malignant CSP, however, the main proliferating cell is an abnormally mobile, HEA319 antigen-, CD10- and CD30-positive myoepithelial cell found to co-express ERFR and CD71 which is abnormal for this cell type but encountered in (myo-)fibroblasts of FA.

Regulation of vimentin expression in cultured human mammary epithelial cells

Using five different monoclonal antibodies to vimentin, we have examined the expression of vimentin in cryostat sections and serum-free cultures of normal human breast tissue. In cryostat sections, myoepithelial cells as well as stromal cells showed immunoreactivity to vimentin, irrespective of the antibody used. In contrast, luminal epithelial cells were negative for vimentin, but positive for keratin K18. In culture, myoepithelial cells showed immunoreactivity to vimentin from their first appearance in monolayer. Moreover, a fraction of luminal epithelial cells expressed vimentin in addition to keratin K18. We found a clear, reversible correlation between proliferation, determined by incorporation of [3H]-TdR, and induction of vimentin in the luminal epithelial cells. Thus, in growth-stimulated cultures on a medium containing cholera toxin (CT), epidermal growth factor (EGF), transferrin (Tf), hydrocortisone (H) and insulin (I), the fraction of vimentin-positive luminal epithelial cells increased, while it decreased within 14 days from approximately 36% to 3% on a medium containing CT and EGF, only. We therefore conclude: (1) vimentin is constantly expressed in myoepithelial cells in situ and in vitro, and (2) expression of vimentin in luminal epithelial cells in vitro is not a result of monolayer cultivation as such, but rather associated with the increased growth rate seen in culture.

Expression of keratin 5 as a distinctive feature of epithelial and biphasic mesotheliomas. An immunohistochemical study using monoclonal antibody AE14

In previous biochemical analyses, keratin 5 (Mr 58,000) has been detected in most mesotheliomas with epithelial component but not in pulmonary adenocarcinomas (Blobel et al., Am J Pathol 121: 235-247, 1985). In the present study, we have characterized a monoclonal antibody, AE14, as being selectively specific for keratin 5 (apart from the reactivity with certain hair proteins) as shown by immunoblotting of gel-electrophoretically separated proteins from various tissues. Immunohistochemical screening of a variety of normal human tissues, using immunoperoxidase microscopy on cryostat sections, revealed the binding of this antibody to the basal, immature cells of stratified squamous epithelia, to basal cells of pseudostratified epithelia, to some myoepithelial cells, thymic reticulum cells, certain pancreatic duct cells, as well as a variable subpopulation of mesothelial cells of the pleura and the peritoneum. In 12/13 epithelial and biphasic mesotheliomas of the pleura, heterogeneous but extended staining with antibody AE14 was seen whereas 21 pulmonary adenocarcinomas were negative or, in six of these cases, showed staining of only a few cells. Among carcinomas from other sites, colonic adenocarcinomas and renal cell carcinomas were negative whereas limited staining was found in some pancreatic adenocarcinomas. It is suggested that antibody AE14 may be useful, as a defined polypeptide-specific reagent, in the histologic distinction between mesotheliomas and most adenocarcinomas. Furthermore, the expression patterns of keratin 5 as detected by antibody AE14 in various normal and malignant epithelial tissues are discussed, particularly their relation to processes of squamous metaplasia and their indication of phenotypic tumor heterogeneity.

Mucoepidermoid mammary carcinoma. Immunohistochemical and biochemical analyses of intermediate filaments

The histological features of mucoepidermoid mammary carcinomas (MMCs) are presented, and criteria for distinguishing these tumours from squamous epithelial metaplasia in other mammary carcinomas are considered. Immunohistochemical and gel-electrophoretic analyses of the intermediate-filament proteins in one MMC case revealed a complex pattern of cytokeratin polypeptide expression. The simple-epithelium-type cytokeratins 7, 8, 18, and 19 were detected mainly in nonsquamous (including mucinous) cells, while the stratified-epithelium-type cytokeratins 5, 6, 14, 16, and 17 were present in squamous cells. However, in both the nonsquamous and squamous regions of the tumour, cytokeratins of the "reverse" type were detected in individual cells. This pattern of single-cell heterogeneity with respect to cytokeratin polypeptide expression suggests that the mixed phenotype of this tumour is not caused by the clonal divergence of tumour cell types. Rather, histogenetically, a pluripotent stem cell with the ability to differentiate into squamous (epidermoid) or mucinous cells might be the starting-point of such a tumour and such differentiation processes may continue to occur during tumour growth. The present case also revealed that mucoepidermoid tumours are not necessarily of low malignancy; there are highly malignant forms with rapid metastasis.

Keratin immunoreactivity as an aid to the diagnosis of persistent adenocarcinoma in irradiated human prostates

Postirradiation prostatic biopsy is believed by many to be the best measure of radiation effectiveness in prostatic cancer. Therapeutic irradiation may induce prostatic glandular atypia, which in its severe form can be confused with persistent adenocarcinoma on prostatic biopsies. In the current study, 37 postirradiation prostate biopsy specimens were evaluated by immunohistochemistry using a specific monoclonal anticytokeratin antibody (KA1) that reacts with the basal cells of normal or hyperplastic glands, but is nonreactive with the lumenal cells or with prostatic carcinoma cells. Persistent carcinoma was observed in 19 cases in which antibody staining was absent. The noncarcinomatous glands retained reactivity, but this reactivity appeared in a new and previously undescribed pattern. The irradiated lesion was characterized by cellular pleomorphisism, with enlargement of nuclei and loss of polarity. The immunoreactivity was seen in the enlarged basal cells and was seen to focally extend to involve the lumenal cell layer. In five of 37 cases, glands were seen that were so atypical on the routinely stained sections that a distinction from cancer could not be made. These same glands in the adjacent section reacted with KA1 in each case allowing us to conclude that the changes were benign. We conclude that the interpretation of postirradiation prostatic biopsy specimens may be aided by immunohistochemistry with this anticytokeratin antibody.

Immunolocalization of the human basal epithelial marker monoclonal antibody 312C8-1 in normal tissue and mammary tumours of rodents

Using immunoperoxidase staining of monoclonal antibody 312C8-1 against 51,000 dalton human keratin polypeptide, immunolocalization was observed in frozen sections of normal tissue and mammary tumours of adult female mice and rats. In normal tissue, the epitope was recognized in myoepithelial cells of the mammary, sweat and salivary glands, and in basal and suprabasal cells of the epidermis. However, the antibody did not react with luminal epithelial cells of the above glands or with mesenchymal cells. In spontaneous mammary tumours of mice, marker-positive tumour cells were distributed only in the outer layer of adenocarcinoma Type A, while they were scattered in some foci of adenocarcinoma Type B, and encircled the epithelial foci of pregnancy dependent tumours (plaque). All layers of epidermoid structures in adenoacanthoma revealed positivity. In rat mammary tumours induced by local dusting with 7, 12-dimethylbenz(a)anthracene (DMBA) powder, the staining pattern of benign tumours was comparable to that of the normal mammary gland. But, in addition to basally situated cells, marker-positive tumour cells were found scattered in the foci of adenocarcinoma, and were not restricted to basal cells in squamous cell carcinoma. The marker was not found in sarcomatous tissue. This antibody can therefore also be applied to rodents, and the staining pattern can be used to identify the epithelial subclass specific marker in normal tissue and in mammary tumours.

Patterns of expression of trichocytic and epithelial cytokeratins in mammalian tissues. III. Hair and nail formation during human fetal development

Cells forming hair and nail material are characterized by the synthesis of members of a particular group of alpha-keratin polypeptides (trichocytic cytokeratins. "T cytokeratins") different from epithelial cytokeratins ("E cytokeratins"). As the precursor cells to trichocytes are derived from fetal epidermal keratinocytes expressing only E cytokeratins, we have studied the patterns of expression of both T and E cytokeratins in developing human hair-and nail-forming tissues of different fetal stages, by immunocytochemistry using antibodies specific for certain T or E cytokeratins and by two-dimensional gel electrophoresis and immunoblotting. In developing hair follicles up to the early bulbous-peg stage (weeks 12-15 of gestational age), only certain E but no T cytokeratins were identified. T cytokeratins were first detected in the late bulbous-peg stage (in week-14 scalp skin) in certain cells of the central part of the hair cone. In hair-producing follicles (weeks 18-25), the lower hair matrix cells were positive for certain E cytokeratins, whereas T cytokeratins appeared in the uppermost portion of the matrix and, most prominently, in the maturing trichocytes. From the late bulbous-peg stage on. E cytokeratin antibody Ks13.1 selectively decorated the inner root sheath. In finger nail "anlagen", T cytokeratins were detected first in week 12 and 13 fetuses, specifically in cells of the lunula region. In more-advanced stages of nail formation, expression of T cytokeratins extended not only to the upper layers of the ventral nail matrix but was also found, albeit more sparsely, in cells of the whole nail-bed epithelium. Throughout these developmental stages, coexpression of T and E cytokeratins was noted in certain cells, including E cytokeratin 19. While in earlier stages E cytokeratins 10/11, characteristic of epidermal-type cornification, were noted in different regions, including the superficial stratum of the nail bed epithelium, they were later restricted to the epithelium of the proximal nail fold. The results show that terminal trichocytic differentiation starts, both in ontogeny and during the steady growth of hairs and nails, in cells expressing E cytokeratins and that coexpression of E and T polypeptides occurs in both kinds of appendages. While in the hair follicle, the change to the exclusive synthesis of T cytokeratins appears to take place relatively abruptly and simply, the development of nail structures from the ventral nail matrix seems to be more gradual and is characterized by more-complex patterns of coexpression of both kinds of cytokeratins.