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.     

Immunohistochemical differentiation of malignant mesothelioma, mesothelial hyperplasia and metastatic adenocarcinoma in serous effusions, utilizing staining for carcinoembryonic antigen, keratin and vimentin

The cytologic diagnosis of malignant mesothelioma and its distinction from mesothelial hyperplasia and metastatic adenocarcinoma is consistently difficult; tissue studies utilizing the immunohistochemical profiles of carcinoembryonic antigen (CEA) and keratin have demonstrated a reproducible distinction between these tumors. Mesothelium contains vimentin in addition to keratin, but its characterization is hindered by its poor preservation in formalin fixatives; alcohol fixation is far superior. Alcohol-fixed, Papanicolaou-stained smears of serous fluids from five cases of reactive mesothelium, five metastatic adenocarcinomas and five malignant mesotheliomas were stained with polyclonal CEA, antikeratin monoclonals AE1 and AE3 (combined) and monoclonal vimentin utilizing the peroxidase-antiperoxidase method. The study revealed the excellent preservation of mesothelial vimentin staining in all three groups. The reactive mesothelium and mesothelioma groups were strongly positive for vimentin and keratin whereas the metastatic adenocarcinoma group was only positive for keratin and CEA (except one case). These findings support the results of previous tissue studies, disclosing CEA staining in the metastatic adenocarcinomas, but not in the mesotheliomas, and the inability of keratin staining to distinguish between the two. The findings also emphasize that positive vimentin staining will usually exclude a metastatic adenocarcinoma, but will not distinguish between neoplastic and reactive mesothelial states.     

Coexpression of cytokeratin and vimentin in Rathke's cysts of the human pituitary gland

Summary Immunohistochemistry with monoclonal and polyclonal antibodies revealed the presence of cytokeratins in epithelial cells of Rathke's cysts in the pars intermedia of the human pituitary gland. With monoclonal antibodies specific for individual cytokeratins, the expression of CK 18, CK 8, CK 7, and CK 19 could be shown in these cells. Within the hypophysis, CK 19 and CK 7 were restricted to Rathke's cysts and a few epithelial cell clusters in the pars tuberalis, whereas other cytokeratins were also present in endocrine cells of the pars distalis. Furthermore, vimentin and, focally, glial fibrillary acidic protein (GFAP) were detected in the cystic epithelia. By double labelling, coexpression of cytokeratin and vimentin, GFAP and cytokeratin, and GFAP and vimentin could be demonstrated. Compiled data of all known cases of coexpression of cytokeratin and vimentin in normal cells reveal physiological correlations and suggest a functional significance of this rare type of coexpression of intermediate filament proteins.     

Immunohistochemical analysis of pulmonary and pleural neoplasms with monoclonal antibodies B72.3 and CSLEX-1

Sequential paraffin sections of 222 epithelial lung tumors comprising all common histologic types, and 31 pleural mesotheliomas of all variants were immunostained with monoclonal antibodies (Mabs) B72.3 and CSLEX-1. Reactivity with Mabs B72.3 and CSLEX-1 respectively was noted in 7/57 and 4/57 squamous carcinomas, in 44/70 and 60/70 adenocarcinomas, 9/16 and 11/16 bronchioloalveolar carcinomas, 8/25 and 14/25 large cell undifferentiated carcinomas, 3/3 and 3/3 adenosquamous carcinomas, 0/11 and 0/11 carcinoids, 0/10 and 2/10 well differentiated neuroendocrine (NE) carcinomas, 4/13 and 5/13 intermediate cell NE carcinomas, 0/17 and 0/17 small cell NE carcinomas, and 0/31 and 1/31 mesotheliomas. In most instances, both Mabs stained the same tumors; however, reactivity with CSLEX-1 was more intense and extensive, and involved more cases. Therefore, regardless of conventional histologic type, staining with Mabs B72.3 and CSLEX-1 defines 4 subsets of lung tumors: one expressing both antigens, two expressing one but not the other, and one expressing neither. The possible biological and/or clinical significance of these subsets remains undetermined. When correlated with conventional histologic tumor types, our findings indicate: 1). both of these Mabs recognize most but not all adenocarcinomas and bronchioloalveolar carcinomas, and since CSLEX-1 stained more cases than B72.3, it may be argued that the former is a broader exocrine phenotype marker than the latter; 2). both of these Mabs select exocrine subsets of large cell undifferentiated carcinomas; 3). both of these Mabs stain exocrine cell subpopulations in well differentiated and intermediate cell NE carcinomas but not in carcinoids or small cell NE carcinomas, and 4). except for rare cases, neither B72.3 nor CSLEX-1 reacts with mesotheliomas regardless of variant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Distribution of vimentin, cytokeratins, and desmosomal-plaque proteins in human nephroblastoma as revealed by specific antibodies: co-existence of cell groups of different degrees of epithelial differentiation

The distribution of cytokeratins, desmosomal-plaque proteins (desmoplakins), and vimentin in nephroblastoma tissue was studied by immunofluorescence microscopy using specific antibodies. In undifferentiated blastema cells, desmosomes, as revealed by antibodies to desmoplakins, preceded the advent of significant amounts of cytokeratins, indicating that desmosomes are early and sensitive markers of epithelial differentiation. Cytokeratin-positive tumor cells were seen in the following distribution patterns: groups of loosely arranged and scattered cells containing only scant cytokeratin fibrils surrounded by negative stroma cells; focal accumulation of cytokeratin-positive cells with cytokeratin-specific cytoplasmic fibril meshwork staining; rosettes of cytokeratin-positive cells without formation of distinct lumina, showing concentration of cytokeratin staining in the center; tubules with distinct lumina made up of cytokeratin-positive cells, with cytokeratin staining concentrated in the subapical cell portions. In cytokeratin-positive cells, the numbers of desmoplakin-positive dots were generally increased; in well-formed tubules, enrichment of desmoplakin-positive spots, corresponding to the subapical skeletal disks, was most conspicuous. Vimentin was demonstrated in stromal areas, but also in blastema cells showing coexpression of desmosomes and vimentin filaments. Moreover, in certain blastema cells, an overlap of cytokeratin and vimentin immunostaining was observed. Epithelial cells of nephroblastoma tubules did not react with vimentin antibodies. Our results show that the appearance of desmosomal plaques, as demonstrated by antibodies to desmoplakins, may be a very early feature of epithelial differentiation, and they also emphasize the value of antibodies to desmoplakins in tumor cell typing and diagnosis.     

Villin: a cytoskeletal protein and a differentiation marker expressed in some human adenocarcinomas

We studied the expression of villin, a microfilament-associated, actin-binding protein typical of brush-border microvilli, in a variety of human carcinomas by applying immunofluorescence microscopy to frozen sections and immunoblotting methods to tissue extracts using a rabbit antiserum and a monoclonal antibody specific for villin. All of the 24 primary and metastatic colorectal adenocarcinomas tested were uniformly and strongly positive for villin, with the immunocytochemical labeling concentrated at the luminal cell margin. In poorly differentiated tumor areas, rudimentary tubules were stained. All of the six tubular adenocarcinomas of the stomach studied as well as two adenocarcinomas of the gall bladder and a hepatocellular carcinoma were also villin-positive. Villin was detectable in 12 of 14 adenocarcinomas of the pancreas; in some of these cases, its distribution was heterogeneous. Among 21 renal cell carcinomas investigated, positivity for villin was seen in nine of 13 clear cell tumors (especially those of grade II), and in all four chromophilic cell tumors; however, all four chromophobe cell tumors studied were negative. Four of 11 endometrial but none of nine ovarian carcinomas were (uniformly or focally) villin positive. Of 18 adenocarcinomas of the lung studied, one was uniformly and four focally positive for villin, while the remainder were negative. All of the other epithelial tumors studied, including 12 adenocarcinomas of the breast and seven epithelial or biphasic pleural mesotheliomas, were villin negative. Our results show that the expression of villin in intestinal epithelial cells is consistently maintained in their corresponding carcinomas, even when the organized brush-border structure has been lost. The presence of villin in some endometrial and pulmonary adenocarcinomas--in contrast to its absence in the respective normal epithelia--suggests that this protein is newly expressed during hyperplasia, dysplasia, or carcinogenesis. Determining the presence or absence of villin and its immunocytochemical staining pattern in metastatic adenocarcinomas may be of some help in determining the type and site of the primary tumor.     

Cytoskeletal proteins as tissue-specific markers in cytopathology

Antibodies to intermediate filament proteins react in a tissue-specific manner and can be used to characterize tumor cells present in thin-needle aspirates from solid tumors, from palpable lymph nodes and cells present in samples from peritoneal and pleural effusions. From our studies so far the following conclusions can be drawn: Polyclonal antisera to cytokeratins can identify carcinoma metastases in thin-needle aspirates from palpable lymph nodes and distinguish them from malignant lymphomas and nonmalignant lesions such as chronic lymphadenitis, which show only vimentin-positive cells. Monoclonal antibodies to specific cytokeratin polypeptides are able to distinguish between different types of epithelial tumor metastases, i.e. metastases from adenocarcinomas and metastases from squamous cell carcinomas. Cells present in peritoneal and pleural effusions can be partly characterized using intermediate filament antisera. We have found that metastatic adenocarcinoma cells from breast, ovary, endometrium, cervix, colon and stomach, as well as squamous cell carcinomas and malignant mesothelioma stain specifically with antibodies to cytokeratin while mesenchymally derived tumors such as malignant lymphomas, malignant melanomas, and fibrosarcomas, are positive for vimentin only. Metastatic tumor cells of epithelial origin present in aspirates from human serous body cavity fluids may coexpress vimentin next to their original cytokeratin intermediate filaments. Benign mesothelial cells present in body cavity fluids frequently coexpress cytokeratins and vimentin. Tumor cells present in thin-needle aspirates from solid tumors such as pleomorphic adenomas of the parotid gland can be identified as such because of their typical patterns of intermediate filament (co-)expression.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnostic significance of coexpression of intermediate filaments in fine needle aspirates of human tumors

A study was undertaken of the diagnostic significance of the coexpression of intermediate filaments in fine needle aspirates of human tumors. Three types of coexpression were found: (1) true coexpression, in which tumor cells simultaneously express more than one intermediate filament protein; (2) pseudocoexpression, in which various tumor cell types from histogenetically different parts of a complex tumor show different results; and (3) false coexpression, in which tumor cells with one or two types of intermediate filaments are present together with benign cells expressing a different filament type. True coexpression of vimentin and keratin was documented in renal cell carcinomas, endometrial carcinomas, certain thyroid carcinomas and Hürthle cell adenomas. Coexpression of keratin and neurofilaments was seen in Merkel cell carcinomas, and coexpression of desmin and vimentin was found in leiomyosarcomas. Keratin, vimentin and neurofilament expression was seen in medullary thyroid carcinomas, and keratin, vimentin and glial fibrillary acidic protein expression was observed in pleomorphic adenomas of the salivary gland. Pseudocoexpression was noted in synovial sarcoma, epithelioid sarcoma, benign cystosarcoma phyllodes of the breast, teratocarcinoma, malignant granular cell tumor, progonoma, Wilms' tumor and triton tumor. Sources of false coexpression are also discussed.     

Distinction between carcinoma cells and mesothelial cells in serous effusions. Usefulness of immunohistochemistry

The usefulness of an immunoperoxidase battery to distinguish carcinomatous from benign effusions was examined. Cell block sections from 90 previously diagnosed effusions were stained with antibodies to Leu-M1, B72.3, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA) and vimentin. The 90 cases comprised 69 carcinomas (23 mammary, 16 ovarian, 10 pulmonary, 7 gastrointestinal [GI] and 13 others), 2 malignant mesotheliomas and 19 cases with reactive mesothelial cells only. EMA and vimentin were the most useful markers for distinguishing carcinoma cells from reactive mesothelial cells. EMA reacted with 86% of the carcinomas while vimentin reacted with 90% of the reactive cases. Leu-M1, B72.3 and CEA, although generally less sensitive than EMA, were also helpful in this regard. Additionally, the use of Leu-M1 and CEA together may help to distinguish pulmonary from GI carcinomas.     

CK5/6 in effusions: no difference between mesothelioma and pulmonary and nonpulmonary adenocarcinoma

OBJECTIVE: To test the performance of CK5/6 for the differentiation between mesothelioma, adenocarcinoma and benign mesothelia/proliferations in effusion cytology. STUDY DESIGN: CKS/6 immunocytochemistry was applied to ethanol-fixed cytospin preparations from 74 benign and malignant effusions. RESULTS: Reactivity was seen in 7 of 8 mesotheliomas and in 9 of 11 benign mesothelial proliferations but also in 11 of l7 pulmonary adenocarcinomas and in 12 of 31 adenocarcinomas of nonpulmonary origin. Reactivity was also found in 3 of 5 non-small cell lung carcinomas and 1 of 1 squamous carcinoma. CONCLUSION: CK5/6 reactivity was found in a considerable proportion of metastatic adenocarcinomas of pulmonary and nonpulmonary origin. The high reactivity rate in pulmonary adenocarcinomas disagrees with the results obtained with histologic sections from solid tumor tissue, and CK5/6 seems to be of very limited value as an additional marker in effusion cytology.     

C-ErbB-2 Oncoprotein Immunostaining In Serous Effusions

The product of c-erbB-2 gene is detected in a proportion of carcinomas from various sites and is generally associated with a high degree of malignancy. A series of 58 effusions containing malignant cells and 16 cytologically negative serous effusions was assessed by immunocyto-chemical methods for c-erbB-2 expression using the monoclonal antibody NCL-B11, which recognizes the internal domain of the c-erbB-2 oncoprotein. Both alcohol-fixed smears and cell blocks from formalin-fixed specimens were used. A crisp, clear cut membrane-associated positive staining was evident in 51 % (30/58) malignant effusions and was restricted to metastatic adenocarcinomas. Breast and ovarian cancers showed the highest incidence of positivity. Mesotheliomas as well as non-neoplastic effusions were consistently negative. Paraffin blocks from formalin-fixed cells displayed a weak immunoreactivity when compared with their alcohol-fixed counterparts. the study shows that the c-erbB-2 oncoprotein can be easily identified in standard cytological smears: it can be of assistance in differentiating adenocarcinomas from mesotheliomas, and in selected cases it can provide a further prognostic indicator, replacing tissue immunohistochemistry.     

Expression of a melanoma-tumor-associated antigen as demonstrated by a monoclonal antibody (D6.1) in cytopathologic preparations of human tumor cells from effusions and needle aspirates

Immunocytopathologic studies were performed on 79 fine needle aspiration biopsies (FNABs) and effusions from 13 melanomas and 57 other human neoplasms with the monoclonal antibody (MAb) D6.1 raised against a partially purified melanoma-tumor-associated antigen (MTAA). The purposes of these studies were (1) to evaluate the ability of MAb 6.1 to react with melanoma cells in cytopathologic preparations and (2) to define the spectrum of reactivity of MAb D6.1 in cytopathologic preparations of non-melanomas. Cytocentrifuge preparations of the cytopathologic specimens were permitted to react with the primary antibody and were then stained by the avidin-biotin-immunoperoxidase method. Thirteen of 13 FNABs of malignant melanomas exhibited staining reactivity with MAb D6.1. Among the nonmelanoma tumors tested, staining reactivity was observed in 30 of 57 specimens. Among specific neoplasms, staining was present in 5 of 11 adenocarcinomas of the breast, 2 of 7 ovarian adenocarcinomas and 5 of 6 metastatic adenocarcinomas from the colon. Among 17 lung cancers examined, staining was noted in 4 of 7 adenocarcinomas, 3 of 4 large-cell undifferentiated carcinomas and 2 of 3 poorly differentiated squamous-cell carcinomas. Two small-cell undifferentiated carcinomas and one carcinoid failed to stain. Three of three adenocarcinomas of the pancreas showed staining. Among the remaining neoplasms examined, one specimen each of carcinoma of the prostate and the cervix and one carcinoma of undetermined primary exhibited staining. Two malignant lymphomas did not stain. Staining of mesothelial cells was observed in three of nine benign effusions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Heterogeneity of intermediate filament expression in human testicular seminomas

Testicular seminoma has in the past been considered to represent a germ cell tumor incapable of further differentiation. In recent years this view has been challenged on the basis of morphologic and chromosomal studies. Moreover, studies of intermediate filaments (IF) of seminoma cells have provided evidence of the capability of seminoma cells to differentiate in different directions. In the present study of the IF protein profile of 26 human testicular seminomas, using frozen as well as formalin-fixed, paraffin-embedded tissues, we report evidence of a heterogeneous differentiation potential inherent in these neoplasms. Thus, in 4 of the seminomas neither cytokeratins nor vimentin were detected; 3 showed vimentin positive cells but no cytokeratins; in 4 seminomas only cytokeratins were detected. In the remaining 15 cases both cytokeratins and vimentin were present, with occasional cells demonstrating coexpression of cytokeratin and vimentin. While the cytokeratins present were mostly of the "simple epithelial type", in 2 instances seminoma cells also contained cytokeratins 4 and 17, normally found in stratified and/or complex glandular epithelia. Furthermore, in 3 cases scattered tumor cells stained for desmin and in 2 other seminomas neurofilaments were identified. All of the cases showed variable positive staining for desmoplakins and desmoglein, indicative of the presence of desmosomes. It can therefore be concluded that, while some seminomas seem to be devoid of IFs, most of them show varied differentiation patterns usually with epithelial features but occasionally also with components commonly regarded as characteristic of myogenic or neurogenic differentiation. These observations may help to elucidate the relationship of seminomas to other germ cell tumors, and also contribute to our understanding of the histogenesis of these neoplasms.     

Cytokeratins in normal lung and lung carcinomas. I. Adenocarcinomas, squamous cell carcinomas and cultured cell lines

The various epithelial cells of the lower respiratory tract and the carcinomas derived from them differ markedly in their differentiation characteristics. Using immunofluorescence microscopy and two-dimensional gel electrophoresis of cytoskeletal proteins from microdissected tissues we have considered whether cytokeratin polypeptides can serve as markers of cell differentiation in epithelia from various parts of the human and bovine lower respiratory tract. In addition , we have compared these protein patterns with those found in the two commonest types of human lung carcinoma and in several cultured lung carcinoma cell lines. By immunofluorescence microscopy, broad spectrum antibodies to cytokeratins stain all epithelial cells of the respiratory tract, including basal, ciliated, goblet, and alveolar cells as well as all tumor cells of adenocarcinomas and squamous cell carcinomas. However, in contrast, selective cytokeratin antibodies reveal cell type-related differences. Basal cells of the bronchial epithelium react with antibodies raised against a specific epidermal keratin polypeptide but not with antibodies derived from cytokeratins characteristic of simple epithelia. When examined by two-dimensional gel electrophoresis, the alveolar cells of human lung show cytokeratin polypeptides typical of simple epithelia (nos. 7, 8, 18 and 19) whereas the bronchial epithelium expresses, in addition, basic cytokeratins (no. 5, small amounts of no. 6) as well as the acidic polypeptides nos. 15 and 17. Bovine alveolar cells also differ from cells of the tracheal epithelium by the absence of a basic cytokeratin polypeptide. All adenocarcinomas of the lung reveal a "simple-epithelium-type" cytokeratin pattern (nos. 7, 8, 18 and 19). In contrast, squamous cell carcinomas of the lung contain an unusual complexity of cytokeratins. We have consistently found polypeptides nos. 5, 6, 8, 13, 17, 18 and 19 and, in some cases, variable amounts of cytokeratins nos. 4, 14 and 15. Several established cell lines derived from human lung carcinomas (SK-LU-1, Calu -1, SK-MES-1 and A-549) show a uniform pattern of cytokeratin polypeptides (nos. 7, 8, 18 and 19), similar to that found in adenocarcinomas. In addition, vimentin filaments are produced in all the cell lines examined, except for SK-LU-1.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fine needle aspiration cytology of atypical carcinoid of the lung

The cytologic features of eight atypical carcinoid tumors of the lung, as observed in fine needle aspiration (FNA) specimens, are described in detail. They were compared with 21 pulmonary squamous-cell carcinomas, 16 adenocarcinomas, 5 small-cell undifferentiated carcinomas, 3 large-cell undifferentiated carcinomas and 1 typical carcinoid tumor. Atypical carcinoid tumor was easily distinguished from the other pulmonary neoplasms in most instances. Only two poorly differentiated squamous-cell carcinomas (one of which had atypical carcinoid as a component) and one small-cell undifferentiated carcinoma had similar cytologic features. One atypical carcinoid also had cytologic features similar to small-cell undifferentiated carcinoma. Because atypical carcinoid and small-cell undifferentiated carcinoma, at times, may be difficult to separate in FNA specimens, surgical resection of all stage I neoplasms with cytologic features evocative of either neoplasm is recommended.     

The value of calretinin and cytokeratin 5/6 as markers for mesothelioma in cell block preparations of serous effusions

Objective: To determine the value of calretinin and cytokeratin (CK) 5/6 in discriminating mesothelioma from adenocarcinoma in serous effusion specimens. Methods: A total of 101 recent, histologically or clinically confirmed malignant effusions with immunostained cell block preparations were reviewed. The cases consisted of 34 mesotheliomas and 67 adenocarcinomas. This included 17 ascitic fluid and 84 pleural fluid samples. The adenocarcinomas included metastatic carcinomas from the breast (12), lung (19), stomach (3), colon (1), pancreas (2), ovary (6) endometrium (1) and 23 histologically confirmed metastases from unknown primary sites. The cases were assessed as negative or positive (>5% of cells stained). The staining pattern was recorded as cytoplasmic, cell membrane, nuclear or cytoplasmic and nuclear staining. Results: Calretinin staining was present in 97% (33/34) of the mesothelioma cases with a majority of them showing both cytoplasmic and nuclear staining (29/33). Only 3% (2/67) of adenocarcinomas were positive for calretinin, one being a lung adenocarcinoma and the other an adenocarcinoma of unknown primary site in an ascitic fluid. Cytokeratin 5/6 staining was also present in 33/34 (97%) of mesothelioma cases. Six (9%) adenocarcinomas were positive, including metastases from the lung (1), breast (1), ovary (2) and unknown primary site (2). Four of the six adenocarcinoma cases positive for CK5/6 were in ascitic fluids. No cases of mesothelioma were negative for both calretinin and CK5/6. Only one adenocarcinoma case, (which was from unknown primary site in an ascitic fluid sample), was positive for both markers. Conclusions: The results confirm that calretinin and CK 5/6 are useful markers for mesothelioma in effusion specimens. CK5/6 staining may be less useful for peritoneal fluid specimens where metastatic adenocarcinomas may be more likely to express the antigen. Further study of ascitic/peritoneal specimens is warranted. However, positive staining, particularly for both antigens, is highly indicative of a mesothelial origin for cells. The two markers make a useful addition to EMA and the panel of adenocarcinoma markers routinely applied to effusion specimens.     

Immunohistochemical evaluation of ras oncogene expression in pulmonary and pleural neoplasms

We undertook an immunohistochemical analysis of human bronchopulmonary epithelial neoplasms and pleural mesotheliomas using a monoclonal antibody which recognizes ras oncogene products (p21ras). The monoclonal antibody, RAP-5, recognizes both unaltered and certain mutated p21ras. Formalin fixed and paraffin embedded tissue samples of 187 lung epithelial tumors and 27 pleural mesotheliomas were investigated; normal and bronchiectatic lungs were similarly studied. Normal lung and pleural tissue did not immunostain except for occasional type II pneumocytes. Reactive type II pneumocytes adjacent to carcinomas and bronchiectasis immunostained consistently. Twenty four/34 (71%) squamous carcinomas immunostained. Only 8/50 (16%) adenocarcinomas immunostained focally and weakly whereas 19/24 (79%) bronchioloalveolar carcinomas immunostained. Eleven/18 (61%) large cell carcinomas immunostained with variable intensity. Eleven/13 (85%) carcinoids, 6/7 (85%) well differentiated neuroendocrine carcinomas, and 18/21 (86%) intermediate cell neuroendocrine carcinomas immunostained while none of 20 small cell neuroendocrine carcinomas immunostained. Only a few mesotheliomas were immunostained focally. Two/14 (14%) epithelial type and 1/9 (11%) biphasic type mesotheliomas immunostained weakly; none of 4 spindle cell mesotheliomas immunostained. We conclude that while at least occasional cases of most types of pulmonary epithelial neoplasms express p21ras, the frequency and intensity of the expression are distinctly greater in certain tumor types such as squamous, bronchioloalveolar, and neuroendocrine neoplasm except for the small cell type. Contrary to these lung epithelial neoplasms, most mesotheliomas did not immunostain for p21ras. Whether the enhanced p21ras expression may point to a different mechanism of transformation or may merely reflect differentiation features remains undetermined.     

Cell biologic properties in explant culture and heterotransplantation of malignant uterine cervical cells

The cell of origin of uterine cervical cancer was studied by using culture, enzyme histochemistry and heterotransplantation. Twenty-seven epidermoid carcinomas (8 large cell keratinizing squamous, 12 large cell nonkeratinizing squamous and 7 small cell nonkeratinizing squamous) and 2 adenocarcinomas of the uterine cervix were placed in culture. An outgrowth of carcinoma cells in vitro was observed in 22 of 29 cases: 6 keratinizing, 8 large cell nonkeratinizing and 6 small cell nonkeratinizing carcinomas and 2 adenocarcinomas. The squamous carcinomas showed a squamous-cell outgrowth pattern, except for one large cell nonkeratinizing and three small cell nonkeratinizing carcinomas that showed a glandular-cell outgrowth pattern. One of three keratinizing carcinomas was transplantable into the subcutis of BALB/c nude mice, producing keratinizing tumors; three of six large cell and one of three small cell nonkeratinizing carcinomas reproduced themselves, while the other two small cell carcinomas produced poorly differentiated adenocarcinomas in mice. The transplanted adenocarcinoma produced a well-differentiated adenocarcinoma resembling the original tumor. Small cell carcinomas and adenocarcinomas contained a heat-stable, L-phenylalanine-sensitive alkaline phosphatase. These results suggest that many uterine cervical cancers originate from the reserve cell.     

Distribution of intermediate-filament proteins in the human enamel organ: unusually complex pattern of coexpression of cytokeratin polypeptides and vimentin

We applied immunohistochemical techniques and gel electrophoresis to examine the distribution of intermediate filaments in human fetal oral epithelium and the epithelia of the human enamel organ. Both methods demonstrated that human enamel epithelia contain cytokeratins 5, 14, and 17, which are typical of the basal cells of stratified epithelia, as well as smaller quantities of cytokeratins 7, 8, 19, and in trace amounts 18, which are characteristic components of simple epithelial cells. In the external enamel epithelium and stellate-reticulum cells, most of these components appeared to be simultaneously expressed. In contrast, the parental oral epithelium was negative for cytokeratin 7, thus indicating possible "neoexpression" during the course of tooth formation. Immunohistochemical procedures using various monoclonal antibodies against vimentin revealed the transient coexpression of vimentin and cytokeratins in the external enamel epithelium and in stellate-reticulum cells during enamel development. The significance of the coexpression of cytokeratins and vimentin is discussed in relation to previous findings obtained in other normal tissues and in the light of the functional processes characteristic of these epithelia.