"Histiocytic markers" in melanoma.

BACKGROUND: Tumor cells of malignant melanoma, the "great imitator," may morphologically mimic almost any cell, including histiocytes. Immunohistochemical stains for histiocytes are often used to distinguish histiocytic lesions that resemble melanomas, but we have noted and others have reported that these markers may be immunoreactive in melanomas. METHODS: We evaluated 43 primary and metastatic melanomas with traditional markers for melanomas (S100, HMB45, and NKI-C3) and common markers used for histiocytes (alpha-1-antitrypsin or AAT, CD68/KP1, HAM56, Mac387, and Muramidase). The extent (<5%, 5 to 30%, 30 to 60%, 60 to 90%, >90%) and intensity (1+ to 4+) of staining were recorded semi-quantitatively. RESULTS: Melanoma immunoreactivity (>5% of tumor cells) was as follows: S100, 100%; HMB45, 91%; NKI, 91%; AAT, 95%; CD68, 86%; HAM56, 26%; Mac387, 7%; and Muramidase, 30%. Among the histiocytic markers, staining by AAT and CD68 was typically diffuse but weak. Staining by HAM56, Mac387, and Muramidase was usually focal. In contrast, the traditional melanoma markers showed diffuse and strong staining. Interpretation of the histiocytic markers was complicated by scattered atypical histiocytes and pigmented tumor cells. CONCLUSION: Melanomas are commonly immunoreactive for histiocytic markers. AAT and CD68 immunostains are diffusely positive almost as frequently as traditional melanoma markers, although with weaker intensity. HAM56, Mac387, and Muramidase are less commonly positive and exhibit focal staining. Therefore, depending on the context, histiocytic markers may not be helpful in differentiating histiocytes and histiocytic tumors from melanomas.

Immunohistochemical analysis of murine CD95/Fas/Apo-1 receptor and its ultrastructural distribution in the thymus.

CD95/Fas/Apo-1 is a cell surface receptor that, upon contact with its ligand, induces cells to die by apoptosis. In view of the importance of Fas receptor (FasR) in immunologic tolerance, an immunohistochemical analysis of FasR expression was performed in the lymphoid and certain parenchymal tissues of normal and mutant MRL/lpr mice using a rabbit polyclonal anti-Fas receptor antibody. FasR was expressed by immunoperoxidase (IP) in the cortex and at the corticomedullary junction of the thymus of normal mice. By immunoelectron microscopy FasR was detected on the cell membrane of normal thymocytes. In MRL/lpr mice, FasR protein expression could not be clearly detected. FasR protein expression was not detected in the heart, liver or ovary by IP, presumably reflecting the low number of receptors in these tissues.

Langerhans cell (eosinophilic) granulomatosis. A clinicopathologic study encompassing 50 years.

We summarize our experience with 238 cases of Langerhans cell granulomatosis (LCG), 198 of whom were followed for a median period of 10.5 years. Our patients did well unless overtreated, and no deaths were attributed to the disorder itself. The disease may appear in unifocal or multifocal form, and treatment is based on this fact. Virtually all patients recovered completely except for occasional residual orthopedic problems or residual diabetes insipidus. Several of the patients underwent subsequent pregnancies without difficulty. The granulomas primarily occur in bone, but lung, skin, and lymph nodal involvement is not uncommon. Involvement of thyroid, thymus, and other sites is rare. The hallmark of the disease is the accumulation of Langerhans cells (LCs). We review the pathology of LCG by histology, electron microscopy, and immunolabeling. LCs originally were identified in squamous epithelium, but these cells are part of the widespread system of dendritic cells. The latter cells, which arise from CD34+ progenitors, are specialized and efficient antigen-presenting cells for T-cell-mediated immunity. In LCG, however, the major associated cells are not T cells, but mature eosinophils: hence the original name eosinophilic granuloma. Confusion about terminology has been based upon the scanty and rather crude pathology reports in the original literature. The term histiocytosis X was meant to cover a spectrum of three diseases--eosinophilic granuloma, Hand-Schüller-Christian disease (HSC), and Letterer-Siwe disease (LS)--but HSC and LS have no basis in pathology and hence the terms are meaningless. The term HSC has become a synonym for multifocal eosinophilic granuloma (LCG). The term LS has been used in reporting a number of benign, malignant, or unknown conditions. We prefer the term LCG to avoid confusion with the term histiocytosis X because there is evidence that the LC is not a member of the mononuclear phagocyte system and hence not a tissue macrophage, and because the use of the term "histiocyte" has become a convenience in much of the literature when reporting incompletely understood diseases.

Immunostaining of small cytologic specimens. Facilitation with cell transfer.

Immunocytochemical study of cytologic specimens is often limited by the number of slides containing diagnostic cells. This study examined the effectiveness of transferring cells from a single smear to multiple slides in order to perform a battery of immunocytochemical stains on limited material. Immunostaining performed on four effusions and five fine needle aspirates yielded the expected results for most of the antibodies commonly employed in diagnostic pathology. Background staining was generally low following cell transfer, and the morphology of the cells was preserved. These results suggest that cell transfer in combination with immunocytochemistry may prove useful in the cytologic diagnosis of malignant lymphoma, neuroendocrine neoplasms, prostatic and mammary adenocarcinoma, and other malignant tumors.

Immunoperoxidase staining of cervicovaginal smears after radiotherapy.

Cervicovaginal smears from 2 women with postirradiation dysplasia, 4 women with postirradiation squamous cell carcinoma of the cervix, 30 women with irradiation atypia and 5 healthy, nonirradiated women were stained immunohistochemically with six keratin antibodies. For four of the antibodies--CK19 (BA17), EMA, PKK-1 and CAM 5.2--squamous cells showing irradiation atypia, postirradiation dysplasia or postirradiation squamous cell carcinoma were more likely to stain positively than were nonirradiated squamous cells. For three of the antibodies in which multiple squamous cells stained positively, the proportion of squamous cells showing postirradiation dysplasia or postirradiation squamous cell carcinoma staining strongly was equal to or greater than the corresponding overall proportion for squamous cells showing irradiation atypia. This was statistically significant with only one antibody, PKK-1. No statistically significant differences were seen in staining of irradiated and nonirradiated squamous cells by MAK-6 and AE1:AE3. The data show that some keratin antigens are more often expressed in the irradiated groups and that there may be differences in the degree of antigen expression between squamous cells showing postirradiation dysplasia or postirradiation squamous cell carcinoma and squamous cells showing irradiation atypia.

Ki-1 antigen expression defines a favorable clinical subset of non-B cell non-Hodgkin's lymphoma.

Immunohistochemical and immunophenotypic analyses were performed on 278 cases of karyotypically abnormal non-Hodgkin's lymphoma (NHL). Excluding cases of lymphoblastic lymphoma or mycosis fungoides, 20 cases showed evidence of non-B cell lineage. T cell lineage was proven by genotypic and immunophenotypic analyses in 15 of the 20 cases; five were of ambiguous lineage. All of the non-B lineage cases were of diffuse histology with a large cell component (DLCL). Twelve cases expressed the Ki-1 antigen; five of these cases also demonstrated a translocation with a break at 5q35. Patients with Ki-1 positive DLCL and t(5q35) had a younger median age compared with non-B cell DLCL without t(5q35). The Ki-1 positive patients had a higher frequency of skin involvement and lower incidence of bone marrow involvement compared with Ki-1 negative DLCL. Survival analysis was performed on 86 cases of B cell DLCL and 18 cases of non-B cell DLCL which were serially ascertained prior to receiving cytotoxic chemotherapy. Median duration of complete remission was significantly longer in the B cell compared with the non-B cell DLCL groups; there was only a trend for decreased overall survival in the non-B cell group. Among the subset of non-B cell lymphomas, overall survival of patients with Ki-1 expressing DLCL was significantly longer than those with Ki-1 negative DLCL, who had a median survival of less than a year. These results show that immunophenotypic, immunohistochemical, and cytogenetic markers can define subsets of patients with non-B cell lymphomas with differing clinical characteristics and outcome.

Tumor marker expression in breast carcinomas and relationship to prognosis. An immunohistochemical study.

A collaborative immunohistochemical study was carried out to examine the expression and prognostic significance of tumor markers in a retrospective series of 233 invasive breast carcinomas. The patterns of tumor marker expression in 94 patients with short remission duration (recurrence within five years) were compared with 50 patients with intermediate (at five to ten years) and 89 patients with long (no recurrence at ten years or longer) remission durations. The antigens examined were carcinoembryonic antigen (CEA), human chorionic gonadotropin (HCG), placental lactogen, alpha-lactalbumin, and pregnancy-specific beta-1 glycoprotein. Carcino-embryonic antigen was the most frequently expressed antigen, whereas HCG was demonstrated least frequently. Also, the ABH isoantigen status was examined using monoclonal antibodies; isoantigen expression was observed in a subset of breast carcinomas, contrary to previous reports of total deletion in breast cancer. Two of the markers, CEA and HCG, were examined by both laboratories, each with two different antisera and also with both PAP and ABC immunohistochemical technics. Meticulous efforts were taken to provide quality control and ensure reproducibility of results. These included the use of serial sections of duplicate pathologic material by both institutions, standardization of experimental conditions and interpretation criteria, double-blind evaluation of exchanged slides, and use of standardized data sheets to record staining extent and intensity. No significant disagreements were observed between data obtained through the different approaches. The steps that were taken to minimize interobserver and interinstitutional differences in this study are presented as a model for collaborative immunohistochemical studies. The expression of tumor markers, alone or in combination, was not found to bear any significant relationship to prognostic indicators, such as the likelihood of recurrence, interval before recurrence, or presence of metastasis.

ABH blood group isoantigen expression in breast carcinomas--an immunohistochemical evaluation using monoclonal antibodies.

The ABH blood group isoantigen status of a retrospective series of 233 invasive breast carcinomas was examined, employing monoclonal antibodies (MCAB) against A, B, and H antigens with the avidin-biotin-peroxidase complex method. In addition, the H antigen was localized with Ulex Europeus Agglutinin I (UEAI) binding. The MCABs provided consistent and specific staining of erythrocytes and endothelium, as well as normal and neoplastic breast epithelium. The anti-H MCAB yielded cleaner background and less intense staining, but otherwise the staining distribution was comparable to the UEA I technique. Contrary to previous reports, deletion of isoantigen expression was not universal in all invasive carcinomas. Whereas 64%, 77%, and 73% of carcinomas from groups A, B, and AB patients, respectively, demonstrated total isoantigen loss, the remaining tumors exhibited variable degrees of isoantigen expression. Moreover, those carcinomas with complete loss of A and B determinants still displayed variable degrees of H immunoreactivity. Carcinomas from group O patients had different degrees of H antigen deletion, with only 12% showing total loss. Statistical analysis revealed that the isoantigen status bore no significant relationship to various epidemiologic, clinical, and pathologic parameters and did not serve as a useful prognostic determinant.