Changes in expression of differentiation markers between normal ovarian cells and derived tumors.

The marker profile of 18 samples of normal human ovarian tissues and 138 samples of their derived tumors was established using 51 monoclonal antibodies directed against intermediate filaments, ovarian carcinoma-specific antigens, general tumor-associated antigens and MHC-I/II antigens. Our data show that vimentin and keratins 7, 8, 18, and 19 were found in both epithelial and some nonepithelial ovarian tumors. Several tumor samples contained additional keratins 4, 10, 13, and 14, as well as desmin. BW 495/36 and to a lesser extent HMFG-2 were usually found in all ovarian tumors that contained simple epithelial keratins, except the absence of HMFG-2 in gonadal tumors as well as in dysgerminomas. In contrast to the keratin antibodies, these two panepithelial antibodies were negative in normal mesothelial cells and granulosa cells of the ovarian follicles. In general, the marker TAG-72 appeared useful for its discrimination between positively stained mucinous adenomas, the ovarian carcinomas as well as germ cell tumors, and the negatively stained gonadal tumors, serous adenomas, and cystomas. OV632 appeared useful in the distinction between negatively stained serous adenomas and positively stained serous carcinomas. In contrast, the monoclonal antibodies OC 125, OV-TL 3, OV-TL 16, and MOv 18 can be considered as pan-ovarian carcinoma markers, however without the discriminative capability as seen for OV632. These ovarian carcinoma-associated antigens were hardly found expressed in gonadal and germ cell tumors, except in the group of endodermal sinus tumors. HLA-I was found to be expressed in almost all nucleated cells, although loss of HLA-I expression was seen in areas of tumor cells. HLA-DR was negative in normal ovarian tissue, but heterogeneous expression was noticed in most of the epithelial tumors.     

Use of monoclonal antibodies to keratin 7 in the differential diagnosis of adenocarcinomas.

Monoclonal antibodies (MAbs) to specific keratin subtypes were prepared and characterized by immunoblotting and immunohistochemical assays on human cell cultures and normal and malignant human tissues. Chain-specific MAbs to keratin 7 (RCK 105, OV-TL 12/30) and keratin 18 (RGE 53, RCK 106, CK18-2), as well as broadly cross-reacting keratin MAbs (RCK 102, OV-TL 12/5) could be shown to react with different types of human epithelial tissues and were therefore tested for their usefulness in the differential diagnosis of carcinomas. The two broad-spectrum antibodies stained virtually all of the more than 350 carcinomas tested, especially when combined, and distinguished them from most nonepithelial tumors. The keratin 18 MAbs distinguished adenocarcinomas (which are keratin 18 positive) from most squamous cell carcinomas (which are generally keratin 18 negative). The MAbs to keratin 7 could be shown to recognize specific subtypes of adenocarcinoma and could, for example, distinguish between ovarian carcinomas (keratin 7 positive) and carcinomas of the gastrointestinal tract (keratin 7 negative), or between transitional cell carcinomas (keratin 7 positive) and prostate cancer (keratin 7 negative). In general, malignancies showed the expected keratin reactivity pattern as concluded from the keratin pattern of its cell of origin or its type of differentiation. The use of an extended series of malignancies did, however, also illustrate that exceptions to this rule exist. For example, certain antibodies to keratin 18 stained tumor areas in squamous cell carcinomas of the lung. Also a certain percentage of tumors, which generally showed no keratin 7 expression, were positive with RCK 105 or OV-TL 12/30. On the other hand, a certain percentage of tumors, which were generally positive for keratin 7, did not show a staining reaction with these MAbs. Furthermore subtle differences between reactivity patterns of different MAbs recognizing the same keratin protein were observed, both in the normal and malignant human tissues, indicating that specific keratin epitopes may be masked in certain tissues and that unmasking of such epitopes can occur with malignant progression. This phenomenon may be of some use in a further subtyping of carcinomas, especially those of the gastrointestinal tract. Despite these exceptional staining patterns, the keratin MAbs described above have proved to be useful tools in the characterization of epithelial tumors in routine histopathology and cytopathology, in which they add to a more refined diagnosis of (adeno)carcinomas.     

Immunohistochemical demonstration of keratin 7 in routinely fixed paraffin-embedded human tissues.

The immunoreactivity of OV-TL 12/30, a monoclonal anti-keratin 7 antibody (Mab), was investigated on frozen as well as paraffin-embedded human tissues. Its reactivity patterns were compared with another well-characterized monoclonal antibody to keratin 7 (RCK 105), and with broadly cross-reacting monoclonal (OV-TL 12/5) as well as polyclonal (pKer) keratin antisera. In frozen sections of normal and malignant human tissues both keratin 7 Mabs gave similar staining patterns. The immunoreactivity for OV-TL 12/30 and the polyclonal antibody (pKer) in tissue sections fixed in 4 per cent formalin or Bouin solution, was completely restored when pretreated with 0.1 per cent pronase, 0.1 per cent trypsin in phosphate-buffered saline (PBS) or with 0.5 per cent pepsin in 0.01 N HCl. Except for loss of immunoreactivity on human normal stomach surface epithelium and glandular mucous cells, Mab OV-TL 12/30 reacted strongly positive with essentially all those formalin- or Bouin-fixed paraffin-embedded tissues that had been shown to stain in non-fixed, frozen sections. In addition to the good correlation in human tissues, a complete correlation between the reactivity on frozen and paraffin-embedded human carcinomas (n = 86) was found as well. While both RCK 105 (anti-keratin 7) and OV-TL 12/5 (anti-keratin 5, 7, 14, 19) did not stain on paraffin-embedded sections, the polyclonal control antiserum (pKer) lost immunoreactivity in some cell types (e.g. mucous cells in compound glands, hepatocytes, pancreatic acinar cells, and proximal and distal convoluted tubules of the kidney). Our study shows that the keratin 7 Mab OV-TL 12/30 is an excellent marker for tumour histopathology since it is reactive in paraffin-embedded formalin-fixed human tissues.     

A series of 14 new monoclonal antibodies to keratins: characterization and value in diagnostic histopathology.

A series of 14 new mouse monoclonal antibodies (MAbs) to keratins is described and the data suggesting their potential value in the differential diagnosis of human tumours are reported. The specificities of individual MAbs of the 'C-series' presented here range from monospecificity for keratin No. 7 (MAbs C-18, C-35, C-62, and C-68), keratin No. 8 (MAbs C-15, C-43, and C-15), and keratin No. 18 (MAbs C-04 and C-08) up to the broadly reacting 'pan-keratin' MAb C-11, with the target epitopes of the remaining four MAbs being shared by different pairs of keratin polypeptides. The results of the biochemical characterization of the MAbs, together with their immunohistochemical staining patterns on frozen as well as on paraffin sections of normal human tissues, suggest that they represent a significant contribution to the growing list of anti-keratin MAbs applicable in both research and routine diagnostic pathology. The immunohistochemical examination of a wide range of human neoplasms with the new MAbs not only confirmed their value in making distinctions between carcinomas, on the one hand, and lymphomas, and gliomas, on the other, but also verified the possibility of more subtle subdivisions within the group of adenocarcinomas and their metastases. Furthermore, the identification of small subsets of breast carcinomas with decreased levels or apparent loss of the keratin No. 7 polypeptide and some cases of stomach carcinoma with apparently induced expression of this keratin suggests that such 'exceptions' must be considered when using keratin spectra as one of the criteria in differential diagnosis.     

Immunohistochemistry of ovarian granulosa cell tumours

Summary Paraffin-embedded material of 47 ovarian tumours primarily diagnosed as granulosa cell tumours, including 2 cases of juvenile granulosa cell tumour, were studied immunohistochemically for the presence of intermediate filament proteins, epithelial membrane antigen and tumour markers. Forty-one lesions, including the 2 juvenile granulosa cell tumours, were vimentin positive, while keratin and epithelial membrane antigen expression could not be detected. Six tumours primarily diagnosed as poorly differentiated malignant granulosa cell tumours were vimentin negative, showed a mild to moderate positivity for keratin and intense positivity with the anti-epithelial membrane antigen antibody. These latter tumours were therefore classified as undifferentiated ovarian carcinomas, corresponding to their significantly poorer prognosis and shorter survival when compared with the granulosa cell tumours. Two of these six tumours were positive for carcino-embryonic antigen. Two small cell carcinomas of the ovary studied in addition expressed keratin in a proportion of tumour cells while no epithelial membrane antigen or vimentin was detectable. None of the tumours tested for alpha-fetoprotein, human chorionic gonadotrophin, human placental alkaline phosphatase and human placental lactogen, were positive.The data indicate the value of antibodies directed against intermediate filament proteins and epithelial membrane antigen to distinguish granulosa cell tumours from poorly differentiated carcinomas, a worthwhile distinction considering the much better prognosis of granulosa cell tumours.     

Immunohistochemical analysis of thyroglobulin and keratin in benign and malignant thyroid tumours

Summary 56 thyroid gland tumours and non neoplastic alterations were studied for keratin and thyroglobulin staining, using the indirect immunoperoxidase method on serial formalin fixed paraffin embedded sections. Papillary carcinomas showed a strong reaction with anti-keratin serum but a weak reaction with anti-thyroglobulin serum. Follicular adenomas and carcinomas showed virtually no reaction for keratin but a strong reaction for thyroglobulin. Undifferentiated and medullary carcinomas did not react with either antiserum, except for single cells in two undifferentiated carcinomas which reacted with anti-keratin serum. In nodular goiters, hyperplastic follicles showed little or no reaction with anti-keratin serum and strong reaction with anti-thyroglobulin serum.It is suggested that this virtually type-specific staining for keratin or thyroglobulin may be related to different degrees of cellular differentiation and organelle content in the tumour cells.This work was supported by a grant from the Wilhelm-Sander-Stiftung (82.007.1)     

Expression of keratins 1, 6, 15, 16, and 20 in normal cervical epithelium, squamous metaplasia, cervical intraepithelial neoplasia, and cervical carcinoma.

Expression of keratins 1, 6, 15, 16, and 20 was examined in normal cervical epithelia, squamous metaplasia, various grades of cervical intraepithelial neoplasia, and both squamous cell carcinomas and adenocarcinomas of the cervix with monospecific antibodies. Ectocervical epithelium contains all of these keratins except keratin 20. They show a heterogeneous distribution, with a basally restricted detection of keratin 15. Endocervical columnar cells were found to contain significant amounts of keratin 16, whereas the subcolumnar reserve cells expressed considerable amounts of keratin 15 and 16, and frequently keratin 6. These reserve cell keratins were also found in immature and mature squamous metaplastic epithelium. In the cervical intraepithelial neoplastic lesions they were generally found with increasing intensity as the severity of the lesion progressed. In the keratinizing variety of squamous cell carcinoma of the cervix, these three keratins seem to constitute an important part of the intermediate filament cytoskeleton, whereas in nonkeratinizing squamous cell carcinoma, they occur to a much lesser extent. Surprisingly, these keratins were also occasionally found in adenocarcinomas. From these data we conclude that the keratin phenotype of reserve cells and endocervical columnar cells is more complex than previously suggested. In particular, the keratins occurring in reserve cells are also present in most of the premalignant and in a considerable number of the malignant lesions of the cervix. The differentiation features of the various carcinoma types are, however, reflected in their specific keratin filament composition.     

The distribution of vimentin and keratin in epithelial and nonepithelial neoplasms. A comprehensive immunohistochemical study on formalin- and alcohol-fixed tumors

Vimentin has been regarded as the intermediate filament characteristic of normal and neoplastic mesenchymal cells and keratins as typical of epithelial cells and the neoplasms derived from them. However, many epithelial cells in tissue culture or in effusion, as well as cells in some solid epithelial neoplasms such as renal, endometrial, ovarian, pulmonary, and thyroid adenocarcinomas, have been shown to coexpress vimentin and keratin. The recent availability of monoclonal antibodies that work reasonably well in paraffin-embedded tissue led us to carry out a comprehensive immunohistochemical study on formalin- and alcohol-fixed specimens of neoplasms in which we used monoclonal antibodies against vimentin. These results were compared with our previous study in which the same tumor tissues were investigated using antibodies against keratin. The antigenicity of vimentin was found to be preserved in all alcohol-fixed specimens and in 63% of formalin-fixed tissues. Vimentin was the sole intermediate filament present in virtually all sarcomas, meningiomas, schwannomas, and melanomas. In addition, variable percentages (10-57%) of carcinomas, neuroendocrine carcinomas, neuroblastomas, thymomas, and mesotheliomas were positive for vimentin, which, except in the neuroblastomas, was coexpressed with keratins. Among the adenocarcinomas, more than 50% of papillary carcinomas of the thyroid, as well as renal, endometrial, ovarian, and lung carcinomas, coexpressed keratins and vimentin. A distinctive paranuclear and basal localization of vimentin was observed in the cells of many of these tumors, in contrast to the predominantly apical distribution of the keratins. The authors conclude that coexpression of vimentin and keratin is more widespread than previously reported and that antibodies to vimentin, by themselves, are of limited value for the differentiation of epithelial from mesenchymal neoplasms.     

Changing patterns of keratin expression during progression of cervical intraepithelial neoplasia.

The expression of keratins in normal cervical epithelia, metaplastic epithelium, and cervical intraepithelial neoplasia (CIN) grades I, II, and III is investigated with a panel of keratin polypeptide-specific monoclonal antibodies. This approach allowed the detection of individual keratins 4, 7, 8, 10, 13, 14, 18, and 19 at the single-cell level. By using an antibody recognizing keratins 5 and 8 (RCK 102) and two antibodies specific for keratin 8 (CAM 5.2 and M 20), it was also possible to derive information on the distribution of keratin 5. Our results show that during immature squamous metaplasia there is an acquisition of keratins typical of squamous epithelium, ie, keratins 4, 5, 13, and 14. This process continues during further differentiation to mature squamous metaplasia. In premalignant lesions the expression pattern of the progenitor reserve cells and immature squamous metaplastic epithelium is partly conserved. However, in most cases an induction in the expression of the keratins 4, 13, and 14 was observed. Furthermore, CIN III shows a more extensive expression of keratins typical of simple epithelia, ie, keratins 8 and 18, as compared to CIN I and CIN II.     

The diagnostic distinction between malignant mesothelioma of the pleura and adenocarcinoma of the lung as defined by a monoclonal antibody (B72.3).

The correct distinction between malignant mesothelioma of the pleura and adenocarcinoma of the lung has become increasingly complex, with a variety of histochemical, immunohistochemical, and ultrastructural studies to be performed on biopsy material. The reliability of immunohistochemical studies has been hampered by the use of polyclonal antisera to "carcinoembryonic antigen (CEA)" and keratin. Hybridoma technology now offers monoclonal antibodies (MAbs) in unlimited quantity and standardized quality to selective ranges of specific antigenic determinants. MAb B72.3, generated against a membrane-enriched fraction of human metastatic breast carcinoma, was used to distinguish malignant mesothelioma of the pleura from adenocarcinoma of the lung in tissue sections and was compared in terms of diagnostic utility with polyclonal anti-keratin and anti-CEA to make the same distinction. Reactivity with MAb B72.3 in at least 10% of tumor cells or more was noted in 19 of 22 adenocarcinomas of the lung (P greater than 0.0001), whereas none of the 20 cases of malignant mesothelioma demonstrated comparable reactivity. Furthermore, MAb B72.3 showed no reactivity with benign mesothelial proliferations. MAb B72.3 thus appears to be an appropriate diagnostic adjunct capable of discriminating between these malignancies.     

Heterogeneity and co-expression of intermediate filament proteins in adenoid cystic carcinoma of salivary glands.

Among a series of 76 adenoid cystic carcinomas (ACC), 51 cases with cibriform or trabecular patterns were selected for an immunohistochemical study. These tumors were composed of three types of cells: basaloid, myoepithelial and ductal luminal acinous or tubular cells with a variable amount of each cell type from one case to another. Monoclonal antibodies (MoAb) against keratins (PKK1, KL1, K8.12, K8.13, K4.62 anti-cytokeratins antibodies) and against vimentin were used. Tubular cells were characteristically marked by anti-cytokeratins MoAb, but with a great heterogeneity of keratin distribution. In myoepithelial cells, keratin was absent or slightly positive and vimentin was present, with co-expression of the two types of filaments in some cells. Like myoepithelial cells, basaloid cells were positive to anti-vimentin antibody and negative or slightly positive to anti-keratin antibodies, with sometimes a co-expression of vimentin and keratin filaments in the same cell. Histogenesis of adenoid cystic carcinomas was discussed. Progenitor intercalated duct reserve cells may change into ductal luminal and myoepithelial tumor cells. Otherwise, basaloid cells, arising also from intercalated duct reserve cells, are able to acquire some secretory organites.     

Prognostic significance of HLA-DR antigen in serous ovarian tumors

Abstract. The antigens encoded by the major histocompability complex (HLA-DR) are cell glycoproteins that play a fundamental role in the regulation of the immune response. The prognosis of ovarian cancer is dependent on the histological type and on the clinical stage at diagnosis. Our study reports the value of HLA-DR antigen as a prognostic marker of ovarian serous adenocarcinoma. We studied 31 cases of serous ovarian cystadenoma, 12 cases of serous ovarian borderline cystadenoma, and 39 cases of well-differentiated cystadenocarcinoma for HLA-DR monoclonal antigen. We also studied the T helper marker (CD4) in the tumor stroma of the relevant cases, given that it is now known that the dependence of immune responsiveness on the class II antigens reflects the central role of these molecules in presenting antigen to T helper cells. HLA-DR was expressed in 20 of 31 cystadenomas (64.5%), 4 of 12 borderline tumors (33.3%), and in 10 of 39 invasive carcinomas (25.6%). CD4 was expressed in 9 of 31 cystadenomas (29%), 5 of 12 borderline tumors (42%), and in 26 of 39 invasive carcinomas (67%). There was a statistically significant difference for the two examined antigens in cystadenomas (p<0.001) and invasive carcinomas (p<0.001), whereas there was no statistical difference in borderline tumors (p<0.5). The results showed decreased expression of HLA-DR and increased expression of CD4 as the lesion progressed to malignancy. The aberrant expression of HLA-DR by epithelial cells of cystadenomas, of borderline tumors, and of invasive adenocarcinomas agrees with the hypothesis of the adenoma/adenocarcinoma sequence. The immune attraction mechanism by low HLADR signaling seems to be of minor importance in the malignant and metastatic potential of serous ovarian tumors.     

Distribution of OV-TL 3 and MOv18 in normal and malignant ovarian tissue.

AIMS--To analyse the distribution of OV-TL 3 and MOv18 in normal ovarian tissue to determine which antibody is most suitable for (radio)immunotherapy of ovarian carcinoma. METHODS--The distribution of OV-TL 3 and MOv18 was determined using immunohistochemistry and flow cytometry. RESULTS--Epithelial and other cells in many tissues, and leucocytes in peripheral blood, bone marrow and spleen stained positively with OV-TL 3. The staining pattern of MOv18 in normal tissues was more restricted and was confined to epithelial cells in the lung, kidney, pancreas, salivary gland, ovary, Fallopian tubes, and cervix. Reactivity was also observed with pneumocytes in the lung, tubuli in the kidney, acinar cells in the salivary gland and pancreas, in the placenta, and with Kupffer cells in the liver. The staining pattern of chimeric MOv18 was identical with the murine form. OV-TL 3 and MOv18 reacted with 100% and 98% (45/46) of the 46 tested epithelial ovarian cancers, respectively. In ovarian carcinoma tissue homogeneous staining of epithelial cells was observed with OV-TL 3 and more heterogeneous staining with MOv18. In 12 and nine patients, respectively, a difference in staining intensity for OV-TL 3 and MOv18 was observed between various tumour samples from the same patient. CONCLUSION--MOv18 has greater therapeutic potential because of its restricted reactivity with normal tissues and especially, in contrast to OV-TL 3, its lack of reactivity with haematopoietic cells.     

Nuclear localization of E-cadherin but not beta-catenin in human ovarian granulosa cell tumours and normal ovarian follicles and ovarian stroma

Ohishi Y, Oda Y, Kurihara S, Kaku T, Kobayashi H, Wake N & Tsuneyoshi M
(2011) Histopathology 58 , 423–432
Nuclear localization of E‐cadherin but not beta‐catenin in human ovarian granulosa cell tumours and normal ovarian follicles and ovarian stroma Aims: The role of misregulated Wnt/beta‐catenin signalling in human ovarian granulosa cell tumour (GCT) has not been well characterized. The aim of this study was to confirm subcellular localization of key molecules of Wnt signalling (beta‐catenin and E‐cadherin) in human ovarian GCTs. Methods and results: Tissue samples taken from 32 human ovarian GCTs and 19 human normal ovaries containing 68 follicles were stained immunohistochemically using monoclonal anti‐beta‐catenin and anti‐E‐cadherin antibodies. None of the 32 GCTs and none of the 68 ovarian follicles showed beta‐catenin nuclear expression (0%). On the other hand, 28 of 32 GCTs (88%) and 53 of 68 normal ovarian follicles (78%) showed nuclear expression of E‐cadherin in granulosa cells. The ovarian stroma in all 19 normal ovaries showed nuclear expression of E‐cadherin but not beta‐catenin. Membranous and cytoplasmic expression was observed variously in ovarian GCT, follicles and stroma. Conclusions: We have confirmed frequent nuclear localization of E‐cadherin but not beta‐catenin in human ovarian GCT, ovarian follicles and stroma. There is no evidence of misregulated Wnt/beta‐catenin signalling (represented by nuclear expression of beta‐catenin) in human ovarian GCT. Nuclear translocation of E‐cadherin might contribute to ovarian folliculogenesis or granulosa/stromal cell differentiation.     

Keratins of different molecular weight in exfoliated mesothelial and adenocarcinoma cells--an aid to cell identification

Keratin profiles of exfoliated mesothelial and adenocarcinoma cells were determined using antisera to different molecular weight keratins (45, 46, 55, 63 kdaltons) and the immunoperoxidase technic. Most metastatic adenocarcinomas in effusions stained for low (45, 46 kdaltons) and intermediate (55 kdaltons) molecular weight keratins but were negative for 63 kdalton keratin. In contrast, most reactive and malignant mesothelial cells in effusions stained strongly for 63 kdalton keratin and keratins of lower molecular weight. This is the first report of high molecular weight (greater than 60 kdaltons) keratin in exfoliated cells of nonepidermal origin. Differences in staining for 63 kdalton keratin between mesothelial and adenocarcinoma cells may help to distinguish these cells in effusions.     

细胞角蛋白7的表达在肿瘤及炎症中的意义

细胞角蛋白(Krt)作为一种中间丝,存在于所有的上皮细胞及部分非上皮细胞.主要作用是维持上皮细胞的机械稳定性和完整性.近年来细胞角蛋白的研究集中在肿瘤的诊断方面,即利用细胞角蛋白在上皮细胞表达的特异性,通过免疫组化技术,运用单克隆抗体进行比对分析,来确定肿瘤的分类、分型或者来源.其中Krt7是一个代表.探讨Krt7的作用,在上皮肿瘤中的分布,以及与细胞角蛋白20(Krt20)在上皮肿瘤中的联合表达情况,对肿瘤的诊断、转移性与原发肿瘤的鉴别等有重要意义.除此之外,Krt7还是一个炎性指标,发挥信号转导中的作用,参与炎症的发生发展,其表达也有利于对某些疾病早期及预后进行监测.     

Neuroendocrine cells in cystic mucinous tumours of the ovary

This histogenesis of cystic mucinous ovarian tumours is still controversial. It has been proposed that these neoplasms may arise from metaplastic ovarian surface epithelium. Others have suggested that these tumours represent monophyletic (intestinal) types of teratoma. Against this background we have studied the presence of different types of neuroendocrine cells in a series of cystic mucinous ovarian tumours. Argyrophil neuroendocrine cells were found almost exclusively in tumours which were histologically classified as borderline or low-grade mucinous carcinomas, whereas these cells were very rare in mucinous cystadenomas and in grade III and IV carcinomas. Several gut peptide hormones could be demonstrated in these cells, but only in borderline tumours and low-grade mucinous carcinomas. Mucin histochemistry did not reveal characteristic patterns in these neoplasms. The results confirm that with regard to the presence of endocrine cells the epithelium of borderline mucinous cystadenomas and mucinous cystadenocarcinomas bears strong resemblance to intestinal epithelium. These findings do not rule out the possibility that these tumours arise by metaplasia from ovarian germinal epithelium but are equally compatible with a teratomatous origin. The epithelium of most benign mucinous cystadenomas resembles that of ovarian inclusion cysts.     

Epithelial cell heterogeneity in the guinea pig thymus: immunohistochemical characterization of four thymic epithelial subsets defined by monoclonal anti-keratin antibodies

Keratins are a family of related polypeptides constitutive of the cytoskeleton of epithelial cells and are never found in nonepithelial tissues. Thymic epithelial cells (TEC), known to induce T cell differentiation, are the keratin-containing cells within the thymus. Using four monoclonal anti-keratin antibodies (KL1, KL4, AE2, AE3) directed against keratins of different molecular weight, we have investigated the guinea pig thymic epithelium. The immunohistochemical analysis of thymic cryostatic sections revealed that the keratin expression of TEC varied according to their location in the thymic lobula; the thymic cortex was specifically stained by AE3 whereas the thymic medulla and the subcapsular cortex were recognized by KL4. In addition, KL1 and AE2 exclusively labeled Hassall's corpuscles. The biochemical analysis of keratins extracted from the thymus showed that each TEC subset was characterized by an unique pattern of keratin polypeptides. This study extends the concept of thymic epithelium heterogeneity and suggests that anti-keratin antibodies which allow the typing of TEC subsets may be valuable tools for studying the differentiation of thymic epithelium and its in vitro function on T lymphocytes.     

Carbohydrate antigen expression in primary tumors, metastatic lesions, and serous effusions from patients diagnosed with epithelial ovarian carcinoma: evidence of up-regulated Tn and Sialyl Tn antigen expression in effusions

The object of this study was the investigation of carbohydrate antigen expression in malignant epithelial cells and benign mesothelial cells in serous effusions from patients diagnosed with epithelial ovarian carcinomas. In addition, to compare antigen expression in carcinoma cells in effusions with those of corresponding primary tumors and metastatic lesions. Sections from 63 malignant effusions from ovarian carcinoma patients and 15 reactive effusions were immunohistochemically stained, using 5 monoclonal antibodies for Lewis(y), Sialyl Lewis(x), Tn, and Sialyl Tn antigens. Tissue sections (n = 97) from corresponding primary ovarian carcinomas and metastatic lesions, as well as from 12 malignant mesotheliomas, were additionally stained using the above panel. Staining for the 4 antigens was seen in carcinoma cells in serous effusions in the majority of cases (range = 71% to 85%). In contrast, immunoreactivity was detected in mesothelial cells in only 6% to 23% of the specimens studied (P < .001 for all 5 markers). With the exception of B3 antibody against Lewis(y) antigen, malignant mesotheliomas stained negative, infrequently showing focal immunoreactivity. An up-regulation of Tn and Sialyl Tn expression was detected in carcinoma cells in effusions when compared with both primary tumors (P < .003 and P < .007, respectively) and metastatic lesions (P < .034 and .041, respectively). Cancer-associated carbohydrate antigens can thus be used as an adjunct in the differentiation between malignant epithelial and reactive mesothelial cells. Ovarian carcinoma cells in effusions show up-regulation of Tn and Sialyl Tn, possibly representing a transient phenotypic alteration facilitating metastasis.     

Immunohistochemical staining patterns of keratins in normal oesophageal epithelium and carcinoma of the oesophagus

To clarify the keratin staining patterns of invasive carcinoma of the oesophagus, 22 cases of formalin-fixed paraffin-embedded surgical specimens were examined immunohistochemically with the labelled streptavidin biotin method using a panel of six different monoclonal anti-keratin antibodies. The antibody reacted adequately when antigen was retrieved in a microwave oven, and the relationship between morphological characteristics and keratin reaction patterns was analyzed in carcinomas and compared with adjacent histologically normal epithelium. In the normal oesophageal epithelium, AE3 and CK8.12 labelled all layer of cells, KS-1A3, E3 and KL1 labelled suprabasal cells, and LL002 selectively labelled the basal cells. In squamous cell carcinomas, AE3, CK8.12, KL1 and LL002 labelled almost all the tumour cells regardless of their differentiation, E3 only labelled keratinized cells, while marked decrease or loss of KS-1A3 staining was seen in all cases examined. Therefore, the characteristic profile of squamous cell carcinoma was a strong and diffuse expression of keratin 14 and 16, strong but localized expression of keratin 17, and loss of keratin 13 expression. Undifferentiated carcinoma totally lacked all keratin reactivity. The findings suggested that the neoplastic epithelial cells showed different keratin reactivity and distribution compared to normal oesophageal epithelium. In addition, histologically normal epithelium, dysplasia and carcinoma-in-situ adjacent to or overlying carcinoma expressed keratin 14.