Prognostic role of PD-L1 and immune-related gene expression profiles in giant cell tumors of bone

Giant cell tumor of bone (GCTB) is a locally aggressive and rarely metastatic tumor, with a relatively unpredictable clinical course. A retrospective series of 46 GCTB and a control group of 24 aneurysmal bone cysts (ABC) were selected with the aim of investigating the PD-L1 expression levels and immune-related gene expression profile, in correlation with clinicopathological features. PD-L1 and Ki67 were immunohistochemically tested in each case. Furthermore, comprehensive molecular analyses were carried out using NanoString technology and nCounter PanCancer Immune Profiling Panel, and the gene expression results were correlated with clinicopathological characteristics. PD-L1 expression was observed in 13/46 (28.3%) GCTB (and in 1/24, 4.2%, control ABC, only) and associated with a shorter disease free interval according to univariate analysis. Moreover, in PD-L1-positive lesions, three genes (CD27, CD6 and IL10) were significantly upregulated (p < 0.01), while two were downregulated (LCK and TLR8, showing borderline significance, p = 0.06). Interestingly, these genes can be related to maturation and immune tolerance of bone tissue microenvironment, suggesting a more immature/anergic phenotype of giant cell tumors. Our findings suggest that PD-L1 immunoreactivity may help to select GCTB patients with a higher risk of recurrence who could potentially benefit from immune checkpoint blockade.

Giant Cell Tumor of Bone: A Model for the in Vitro Human Osteoclast Characterization

The in vitro growth pattern of cells obtained from bioptic material of ten patients with giant cell tumor of bone (GCT) was investigated. Cytochemical reactions and monoclonal antibodies raised against macrophage markers were tested on the two histologically identifiable GCT cell populations. Only monoclonal antibody EBM/11 stained both mononuclear and giant cells. EBM/11 positivity and resistance of acid phosphatase to high doses of tartrate strongly suggest that both mononuclear and giant cells belong to the same lineage.

CSF1R inhibition with emactuzumab in locally advanced diffuse-type tenosynovial giant cell tumours of the soft tissue: a dose-escalation and dose-expansion phase 1 study

BACKGROUND

Diffuse-type tenosynovial giant cell tumour (dt-GCT) of the soft tissue (alternatively known as pigmented villonodular synovitis), an orphan disease with unmet medical need, is characterised by an overexpression of colony-stimulating factor 1 (CSF1), and is usually caused by a chromosomal translocation involving CSF1. CSF1 receptor (CSF1R) activation leads to the recruitment of CSF1R-expressing cells of the mononuclear phagocyte lineage that constitute the tumor mass in dt-GCT. Emactuzumab (RG7155) is a novel monoclonal antibody that inhibits CSF1R activation. We have assessed the safety, tolerability and activity of emactuzumab in patients with Dt-GCT of the soft tissue.

METHODS

In this phase 1, first-in-human dose-escalation and dose-expansion study, eligible patients were aged 18 years or older with dt-GCT of the soft tissue with locally advanced disease or resectable tumours requiring extensive surgery, an Eastern Cooperative Oncology Group performance status of 1 or less, measurable disease according to Response Evaluation Criteria In Solid Tumors version 1.1, and adequate end-organ function. Patients with GCT of the bone were not eligible. Patients received intravenous emactuzumab at 900 mg, 1350 mg, or 2000 mg every 2 weeks in the dose-escalation phase and at the optimal biological dose in a dose-expansion phase. The primary objective was to evaluate the safety and tolerability of emactuzumab, and to determine the maximum tolerated dose or optimal biological dose. All treated patients were included in the analyses. Expansion cohorts are currently ongoing. This study is registered with ClinicalTrials.gov, number NCT01494688.

FINDINGS

Between July 26, 2012, and Oct 21, 2013, 12 patients were enrolled in the dose-escalation phase. No dose-limiting toxicities were noted in the dose-escalation cohort; on the basis of pharmacokinetic, pharmacodynamic, and safety information, we chose a dose of 1000 mg every 2 week for the dose-expansion cohort, into which 17 patients were enrolled. Owing to different cutoff dates for safety and efficacy readouts, the safety population comprised 25 patients. Common adverse events after emactuzumab treatment were facial oedema (16 [64%] of 25 patients), asthenia (14 [56%]), and pruritus (14 [56%]). Five serious adverse events (periorbital oedema, lupus erythematosus [occurring twice], erythema, and dermohypodermitis all experienced by one [4%] patient each) were reported in five patients. Three of the five serious adverse events-periorbital oedema (one [4%]), lupus erythematosus (one [4%]), and dermohypodermitis (one [4%])-were assessed as grade 3. Two other grade 3 events were reported: mucositis (one [4%]) and fatigue (one [4%]). 24 (86%) of 28 patients achieved an objective response; two (7%) patients achieved a complete response.

INTERPRETATION

Further study of dt-GCT is warranted and different possibilities, such as an international collaboration with cooperative groups to assure appropriate recruitment in this rare disease, are currently being assessed.

FUNDING

F Hoffmann-La Roche.

Transformation of cells in human bone tumor cultures

Two cell lines from tumors of 16 patients with osteosarcoma and two cell lines from 5 patients with giant cell tumor of bone showed conversion of cell type after 2 to 13 months in culture. Transformed cells of epithelial like morphology appeared in small focal areas and rapidly overgrew nontransformed cells. These cells were characterized by rapid growth, loss of contact inhibition, and growth in soft agar. Attempts to demonstrate virus(es) by electron microscopy, treatment with chemicals, or by inoculation of human cell lines were thus far unsuccessful. Antigens not present in parental cultures were observed in the transformed cells by fixed immunofluorescence test with sera of 13 and 20 osteosarcoma patients and 3 of 8 patients with giant cell tumor of bone. Absorption of positive sera with transformed cells of either osteosarcoma or giant cell tumor removed the reaction but not with absorption with heterophile material or mycoplasma. Presence of group-specific-like antigen (gs-3) in the transformed cells (but not in parent cultures) was shown by immunofluorescence. Fluids of transformed cultures contained heavy RNA similar to that of oncornaviruses. These findings suggest the presence of viral information in some human bone tumors.

Benign giant-cell tumor of the common bile duct: A case report

Primary giant-cell tumors rarely arise in the common bile duct. We herein report a case of primary giant-cell tumor of the common bile duct. The patient was an 81-year-old male who was diagnosed with a well-defined 1.2-cm mass projecting into the lumen of the middle common bile duct. Excision of the gallbladder and extrahepatic bile duct and a Roux-en-Y cholangiojejunostomy were performed. Histologically, the tumor had no association with carcinomas of epithelial origin and was similar to giant-cell tumors of the bone. The tumor consisted of a mixture of mononuclear and multinucleated osteoclast-like giant cells. The mononuclear cells showed no atypical features, and their nuclei were similar to those of the multinucleated giant cells. CD68 was expressed on the mononuclear and multinucleated osteoclast-like giant cells, whereas CD163 immunoreactivity was restricted to the mononuclear cells. Six months after the operation, the patient was still alive and had no recurrence. The interest of this case lies in the rarity of this entity, the difficulty of preoperative diagnosis, and this tumor’s possible confusion with other malignant tumors.

Apolipoprotein D in CD34-positive and CD34-negative cutaneous neoplasms: a useful marker in differentiating superficial acral fibromyxoma from dermatofibrosarcoma protuberans

More recent techniques to characterize the genetic profile of soft-tissue tumors include the use of gene arrays. Using this technique, Apolipoprotein D (Apo D), a 33-kDa glycoprotein component of high-density lipoprotein, has been found to be highly expressed in dermatofibrosarcoma protuberans. To corroborate these results, we sought to ascertain the utility of Apo D by investigating its sensitivity and specificity in a variety of CD34-positive and CD34-negative cutaneous neoplasms including superficial acral fibromyxoma, sclerotic fibromas, and cellular dermatofibromas. Of interest, we found absence of Apo D expression in all four cases of superficial acral fibromyxoma. Of the remaining CD34-positive lesions, Apo D expression was noted in 35/36 (97%) cases of dermatofibrosarcoma protuberans, 3/5 (60%) giant-cell fibroblastomas, 4/4 (100%) sclerotic fibromas, 8/8 (100%) neurofibromas, and 1/1 (100%) solitary fibrous tumor. Of the CD34-negative lesions, Apo D expression was noted in 2/22 (9%) regular dermatofibroma, 23/45 (51%) cellular dermatofibroma, 10/10 (100%) malignant fibrous histiocytoma, 9/10 (90%) atypical fibroxanthoma, 7/8 (86%) cellular neurothekeoma, 9/9 (100%) malignant melanoma, 8/8 (100%) melanocytic nevi (100%), 0/2 superficial angiomyxoma, 0/15 fibromatosis, 0/1 nodular fasciitis, and 1/2 (50%) desmoplastic fibroblastomas. In summary, our findings indicate that Apo D expression is not specific to dermatofibrosarcoma protuberans. Its principal use as an immunohistochemical adjunct lies in its utility in differentiating superficial acral fibromyxoma from dermatofibrosarcoma protuberans. Although strong positive staining of Apo D in a markedly atypical fibrohistiocytic lesion is suggestive of atypical fibroxanthoma and/or malignant fibrous histiocytoma, further studies with the inclusion of other atypical spindled cell neoplasms are required to conclusively prove the same.

Osteoclast-like giant-cell tumor of the parotid with salivary duct carcinoma: case report and cytologic, histologic, and immunohistochemical findings

Primary giant-cell tumor of the salivary gland is a rare lesion with an incompletely characterized histogenesis. To the best of our knowledge, only 16 cases have been previously documented in the English-language literature. We report a new case, which occurred in a 75-year-old man who presented with a parotid mass and cervical lymphadenopathy. The patient underwent a left total parotidectomy and cervical lymph node dissection. As far as we know, ours is the only reported case of a primary giant-cell tumor of the salivary gland in which the patient presented with lymph node metastasis. Because so little is known about giant-cell tumor of the salivary gland, we use the occasion of this case report to describe the cytologic, histologic, and immunohistochemical characteristics that we observed.

Unusual aggressive course of a giant cell tumor of soft tissue during immunosuppressive therapy

Giant cell tumor of soft tissue with low malignant potential (GCT-ST) is a low-grade, primary soft tissue sarcoma with histological and clinical features similar to giant cell tumor of the bone. The main tumor localizations are the extremities, but it may also occur in the head and neck region. GCT-ST shows a recurrence rate of approximately 15%, but it very rarely metastasizes. The risk of cancer development, especially of the skin, is up to fivefold increased in immunosuppressed patients after organ transplantation. The association of sarcomas and immunosuppressive therapy is best known for Kaposi sarcomas, whereas other types of sarcomas are rarely found. We report of a GCT-ST of low malignant potential, which developed under long-term immunosuppression in a patient 12 years after heart transplantation. The tumor presented with an unusual aggressive course and metastatic site: the parotid gland. Therefore, we suggest that in patients with immunosuppression, even low malignant cancerous lesions should be carefully observed, as their local behavior may be aggressive with development of metastasis.

AM-3K, an anti-macrophage antibody, recognizes CD163, a molecule associated with an anti-inflammatory macrophage phenotype

CD163 is a member of the scavenger receptor cysteine-rich superfamily restricted to the monocyte/macrophage lineage and is thought to be a useful marker for anti-inflammatory or alternatively activated macrophages. In this study we used mass spectrometric analysis to determine that the antigen recognized by the antibody AM-3K, which we previously generated as a tissue macrophage-specific monoclonal antibody, was CD163. An anti-inflammatory subtype of macrophages stimulated by dexamethasone or interleukin-10 showed strong reactivity for AM-3K and increased expression of CD163 mRNA. Immunohistochemical staining of routinely processed pathological specimens revealed that AM-3K recognized a specialized subpopulation of macrophages. In granulomatous diseases such as tuberculosis, sarcoidosis, or foreign body reactions, tissue macrophages around granulomas, but not component cells of the granulomas such as epithelioid cells and multinucleated giant cells, showed positive staining for AM-3K. In atherosclerotic lesions, scattered macrophages in diffuse intimal lesions were strongly positive for AM-3K, whereas foamy macrophages in atheromatous plaques demonstrated only weak staining. We therefore suggest that, in routine pathological specimens, AM-3K is a useful marker for anti-inflammatory macrophages because these cells can be distinguished from inflammatory or classically activated macrophages. Because AM-3K cross-reacts with macrophage subpopulations in different animal species including rats, guinea pigs, rabbits, cats, dogs, goats, pigs, bovine species, horses, monkeys, and cetaceans, it will have wide application for detection of CD163 in various animals.

Osteoclast-like giant cell tumor in mucinous cystadenocarcinoma of the pancreas: an immunohistochemical and molecular analysis

Osteoclast-like giant cell tumors (OLGT) are rare neoplasms of the pancreas and mostly associated with ductal adenocarcinomas. In this report, we present the rare case of OLGT associated with mucinous cystadenocarcinoma (MCC). We investigated the expression profile of both tumors by methods of molecular biology and immunohistochemistry. The panel of markers included osteopontin, her2/neu, mismatch repair genes, K-ras, p53, E-cadherin, VEGF-C, and podoplanin. Osteopontin was expressed by the osteoclast-like giant cells but not by the mononuclear tumor cells of the OLGT. We detected an amplification and overexpression of her2/neu in the MCC but not in the OLGT. Although we observed an immunohistochemical expression of hMSH2 and hMLH1 in the OLGT, we were not able to confirm this result by western blot analysis. We also did not find any microsatellite instability (D2S123, BAT26). While mutation of K-ras codon 12 was found in both tumor components, there was wild-type DNA of p53. E-cadherin was expressed in MCC but not in OLGT. VEGF-C was only positive in osteoclast-like giant cells and some of the mononuclear cells of OLGT. The vessel-rich stroma of OLGT did not present any podoplanin-positive lymphatic vessel. The observation of our case and others in the published literature may indicate separating OLGT with undifferentiated carcinoma from OLGT with MCC for the better clinical outcome of the latter.

Giant-cell fibroblastoma in a patient with a bone-marrow transplant

A case of an epigastric giant-cell fibroblastoma is reported in a 6-year-old girl who had undergone a bone-marrow transplant for severe combined immunodeficiency secondary to adenosine deaminase deficiency. A small subcutaneous nodule had been excised from the epigastrium at age 12 months.

Apoptosis in giant cell tumors of bone

Although giant cell tumor of bone (GCT) is characterized by the extensive multinucleated giant cells among mononuclear stromal cells, proliferation of these cells and multinucleation are not without limit in certain cases. Few studies on oncogenesis of GCT have focused on the negative growth control, including growth arrest and apoptosis. The purpose of this study was to investigate the mechanism of cell death in multinucleated giant cells and stromal cells of GCT. In this study, we have demonstrated that GCT cells can undergo apoptosis. The cells in surgical specimen were positively stained in situ nick end labeling methods, and electron micrographs showed the morphological changes associated with apoptosis in some of stromal cells and multinucleated giant cells. A candidate responsible for this apoptosis was then examined using cultured GCT cells. We focused on Fas that is a major trigger of apoptosis. Cultured GCT cells expressed detectable amount of Fas on their surface. Although GCT cells did a little undergo apoptosis following treatment with anti-Fas alone, combination treatment with cyclohexamide led to an increase in apoptosis of the GCT cells. These data suggested that the sensitizing activity of cyclohexamide on anti-Fas mediated cytotoxicity could happen in vitro.

Extraorbital giant cell angiofibroma

A number of intriguing fibrovascular mesenchymal proliferations with benign or low grade malignant potential have recently been described. Giant cell angiofibroma was introduced as an entity by Dei Tos et al. in 1995 and initially considered to be a lesion of the orbit. We describe an extraorbital example, indicating that giant cell angiofibroma is not confined to the orbit. Immunologically, giant cell angiofibroma is positive for CD 34, bcl-2 and vimentin, and negative for epithelial and muscle markers, and S-100. The tumor shares several morphological and immunological properties with giant cell fibroblastoma and solitary fibrous tumor, yet it features a histology sufficiently characteristic to allow its categorization as a separate entity. The recommended treatment is complete but conservative excision. Metastases have not been reported.

Induction of human osteoclast-like cells by treatment of blood monocytes with anti-fusion regulatory protein-1/CD98 monoclonal antibodies

We have developed a new and simple system of human osteoclast formation by fusing peripheral blood monocytes with anti-Fusion Regulatory Protein-1 (anti-FRP-1) monoclonal antibody (mAb). When human blood monocytes were cultured in the presence of anti-FRP-1/CD98 mAbs, polykaryocytes began to appear at approximately 15 h and increased in size with time until 3-4 days of incubation with anti-FRP-1 mAb. These fused cells showed positive staining in tartrate-resistant acid phosphatase, possessed numerous calcitonin receptors, and were capable of bone resorption. These results strongly suggest that anti-FRP-1 antibody-induced multinucleated cells are osteoclasts. Furthermore, FRP-1 antigens were detected in osteoclasts isolated from human bone and in the osteoclast-like cells obtained from human giant cell tumors of bone.

Giant cell tumor of the ovary. Immunohistochemical evidence of origin from stromal ovarian cells

Giant cell tumor (GCT) of the ovary is a rare condition, found almost invariably in the context of a mucinous tumor and presenting a microscopic picture indistinguishable from GCT of bone. We describe a case of GCT in the wall of a serous cyst of the ovary. An immunohistochemical study was performed using a panel of antibodies to epithelial, mesenchymal and leukocyte antigens. Mononuclear and giant tumor cells were positive for vimentin; CD 68 and LCA were found only in giant cells whereas actin was only found in mononuclear tumor cells. The immunophenotypic profile of the stromal cells of the residual ovary was identical to that of mononuclear tumor cells. The presented data suggest that GCT of the ovary is probably a non-neoplastic lesion of the mesenchymal stromal cells that react against substances of the associated tumor or cyst.

Transforming growth factor alpha and CD68 immunoreactivity in giant cell tumours of bone: a study on the nature of stromal and giant cells, and their interrelations

To clarify the nature of neoplastic cells, 17 giant cell tumours of bone were studied histologically and immunohistochemically. L1 antigen and S-100 protein were not detected in the tumour giant cells and stromal cells, although present in non-neoplastic macrophages. The giant cells in all the lesions, some stromal cells, and osteoclasts in the normal bone showed CD68 and transforming growth factor alpha (TGF alpha) immunoreactivity. Fibrohistiocytic antigen, factor XIIIa, was expressed in large numbers of stromal cells in all lesions. Some stromal cells expressed alpha-smooth muscle actin and osteocalcin. These immunohistochemical results suggested that the stromal cells of giant cell tumours of bone showed histiocytic and occasional myofibroblastic and osteoblastic differentiation. Proliferating cell nuclear antigen was demonstrated in the nuclei of the stromal cells only, indicating that these were the sole proliferating elements. TGF alpha produced by the giant cells and some stromal cells may play a role as a mediator for the attraction and/or proliferation of the precursor cells, and may suppress the activity of osteoblastic stromal cells, resulting in restricted bone formation in giant cell tumours.

[Generation and characterization of monoclonal antibody GCF-5 to human giant cell tumor of bone]

Hybrid cell line has been derived from fusion of mouse myeloma (Sp2/0-Ag14) cell and spleen cell from mouse which was immunized with cultured cells of giant cell tumor of bone (GCT). Hybrid cells produce monoclonal antibody against GCT associated antigen in the surface of the tumor cells. The monoclonal antibody was detected by immunoperoxidase staining and was designated by GCF-5. There were more than eighty per cent of tested GCT which showed this antigen. It had no cross reaction with many kinds of normal tissue, HLA antigen, alpha-Fetal Protein, Carcino-Embryonic Antigen and beta-Microglobulin. The subclass of the antibody is IgG1. The hybridoma has been cultured and stored under -196 degrees C for more than eight months and its secretion remains stable.

Histochemical and immunohistochemical characterization of cells constituting the giant cell tumor of bone

Enzymatic activity and cell membrane proteins were characterized in cells from five giant cell tumors of bone (GCTs). Naphthyl alpha esterase (NAE) and acid phosphatase (AP) activity was noted within both the mononuclear and multinucleated cells of each tumor. In each tumor, all mononucleated cell populations displayed tartrate-sensitive AP activity, whereas the multinucleated cell populations demonstrated variable expression of tartrate-sensitive and tartrate-resistant AP activity. Analysis of cell membrane proteins included attempts at immunodetection of mannose receptor, OKM-1 antigen (OKM-1a), colony-stimulating factor-1 receptor (CSF-1r), and platelet-derived growth factor receptor (PDGFr). None of these membrane antigens were elicited on multinucleated cells. In contrast, the mannose receptor, OKM-1a, and PDGFr all were detected on the mononucleated cells within each tumor. These data demonstrate that a population of mononucleated, not multinucleated cells, expresses features unique to mature mononuclear phagocytes and establishes the presence of a membrane receptor, PDGFr, associated with mitogenesis of mesenchymal cells.

Phenotypic characterisation of mononuclear and multinucleated cells of giant cell tumour of bone

Studies were carried out on 3 giant cell tumours of bone (GCTB) to characterise further the cells forming the distinctive mononuclear and multinucleated components. Samples of tumours were grown as explants in vitro and implanted subcutaneously in athymic mice. Cells were characterised in terms of their cell morphology and cytochemical, antigenic and functional phenotype. In culture, giant cells formed a non-proliferative, relatively homogeneous population of cells which expressed features characteristic of the osteoclast phenotype. The mononuclear cell component was heterogeneous and included macrophage-like cells, which persisted for a short time in culture, and fibroblast-like cells which proliferated. In subcutaneous implants, the fibroblast-like cells formed a tissue which included areas of bone formation associated with regions of alkaline phosphatase activity. These observations are consistent with earlier suggestions that the neoplastic component in GCTB consists of a mononuclear stromal cell which elicits a macrophage/osteoclast response.

Production and characterization of new monoclonal antibodies to human osteoclasts

Two monoclonal antibodies raised against human osteoclastoma were found to show antiosteoclastic activity on frozen sections of tumor. Immunoreactivity was localized on the membrane surface. These antibodies exhibited no activity against tissue macrophages and human visceral tissue except kidney, where they stained tubules but not glomeruli. In addition, no activity was observed against rabbit or rat osteoclasts, suggesting that they might react with unique epitopes on human osteoclasts.

[Identification of cytokines produced by cells cultured from human giant cell tumors of bone]

Morphological and biochemical studies were performed using tissue culture methods in 14 cases of giant cell tumor of bone. Primary cultures consisted of three types of cells, multinucleated giant cells, mononuclear round cells and spindle-shaped cells. The round cells were considered to be infiltrating macrophages, not neoplastic cells, according to the results obtained by morphological and immunohistochemical studies. The spindle-shaped cells were apparently neoplastic since they extensively proliferated and showed chromosomal abnormalities. Western blotting analysis of the supernatant fluid from the culture of the spindle-shaped cells showed the presence of several cytokines; M-CSF, IFN-gamma, TNF-alpha, which were known to show chemotactic, differentiation-inducing and activating effects on macrophages. When the conditioned mediums of cultured spindle-shaped cells were added to the culture of U-937 macrophage cell line, U-937 cells were induced to differentiate and became multinucleated giant cells. The results indicate that the spindle-shaped cells which could be passaged are neoplastic elements and that the cytokines produced by these cells have a significant role in clinicopathological status of the giant cell tumor of bone.

Production and characterization of osteoclast-selective monoclonal antibodies that distinguish between multinucleated cells derived from different human tissues

Osteoclastoma-derived giant cells were used to produce 11 mouse monoclonal antibodies (MAb) reactive against human osteoclasts on undecalcified sections of adult human bone. All exhibited unique reactivities across a wide range of human tissues. Three in particular demonstrated distinctive reactivities; C35 was highly selective for bone osteoclasts, C27 showed selective reactivity for osteoclasts, tissue macrophages and blood-borne monocytes, and C22 showed selective membrane staining of osteoclasts. Consequently, C22 was used to coat Dynabeads to affinity-purify viable human osteoclasts from osteoclastoma-derived cell suspensions. Immunocytochemical staining of inflammatory osteoarthritic synovium/granulation tissue demonstrated positivity in the majority of giant cells with MAb C22 and C27. In contrast, C35 reacted with only very occasional giant cells. Furthermore, multinucleated cells formed in long-term human bone marrow cultures demonstrated similar selective staining. C27 stained all giant cells and the majority of mononuclear cells. C22 detected only a small proportion of giant cells. In contrast to its staining on bone osteoclasts, C22 demonstrated granular cytoplasmic staining in cultured giant cells. C35 stained no cells at all in these cultures. These MAb can therefore distinguish between giant cells of various origins and authentic mature osteoclasts. Alternatively, they can recognize antigens expressed at different stages of osteoclast differentiation and therefore provide an excellent tool for the study of the human osteoclast lineage.

[Cellular biological study of giant cell tumor of bone: a 10-year summary]

This article is a summary of the main research accomplishments on giant cell tumor of bone (GCT) carried out in this laboratory in the past ten years. The stromal cells (STC) in GCT have long been regarded as a single neoplastic element. By means of immunological method they are segregated into EA rosette-forming cells (RFC) and non-rosette-forming cells (NRFC). It is herein demonstrated that RFC are macrophages of the defensive mechanism, while NRFC bear the hallmarks of neoplastic cells. The views concerning the nature of the multinucleated giant cells (MGC) so far remains controversial. One of the authors, on the basis of the survival time in thin vitro culture, classifies them into short survival MGC (S-MGC) and long survival MGC (L-MGC). Immunological and cytochemical evidences indicate that S-MGC are similar to osteoblasts and foreign-body giant cells and express macrophage antigen. Moreover, macrophages in GCT can actually form MGC. L-MGC, however, present characteristics of neoplastic cells which are known to be able to form tumor giant cells. Thus the concept of GCT has been renovated. Evaluation of the aggressiveness of GCT is important and challenging, as the Jaffe grading system is no longer widely considered valid. In our laboratory this problem has been approached by cytomorphometry, nuclear DNA-cytometry and multifactor analysis techniques. Parameters which are conducive to predicting the prognosis of GCT are found, which would render help to clinical diagnosis and research of this semimalignant tumor.

The osteoclast functional antigen, implicated in the regulation of bone resorption, is biochemically related to the vitronectin receptor

We have defined the structure of the Osteoclast Functional Antigen (OFA) by immunological and biochemical means. OFA is an abundant surface antigen in human and animal osteoclasts and has been characterized previously by monoclonal antibodies 13C2 and 23C6, one of which mimicks the inhibitory activity of calcitonin on osteoclastic bone resorption. By the following criteria we show that OFA is a member of the integrin family of extracellular matrix receptors and is identical, or at least highly related, to the vitronectin receptor (VNR) previously isolated from placenta and melanoma cells. Immunoprecipitation analysis demonstrates that OFA from osteoclasts and a monkey kidney cell line Vero is a heterodimeric molecule of 140 kD (alpha chain) and 85 kD (beta chain) under nonreducing conditions; on reduction at least one low molecular mass (alpha') species (of approximately 30-kD size) is released, resulting in a 120/100-kD dimer. Immunoblots of OFA isolated from osteoclasts and Vero cells and VNR purified from placenta and probed with heterosera to OFA and monoclonal antibodies to platelet gp111a (VNR beta chain) show immunological cross-reactivity between the alpha chains of OFA and VNR and the use of gp111a as a beta chain by both. OFA from Vero cells binds to an Arg-Gly-Asp containing peptide (GRGDSPPK) isolating a heterodimer recognized by anti-OFA monoclonal antibodies, 13C2 and 23C6. Immunohistochemical analysis showed a similar tissue distribution in humans for the antigen recognized by anti-OFA antibodies, a monoclonal antibody, LM142, raised to melanoma VNR, polyclonal antibodies to the placental VNR and a monoclonal antibody to the presumptive VNR beta chain, platelet glycoprotein 111a. Finally, NH2 terminal amino acid sequencing showed that the amino-terminus of the monkey alpha chain was identical in the 12 assigned residues to that of human VNR alpha chain. The beta chain sequence of OFA differed at least 1 (and up to 4) positions from platelet gp111a (VNR beta) in the first 18 amino acids sequenced. These, and other, data provide the first indication of a function for the VNR and suggest that cell-cell and cell-extracellular matrix interactions involving integrins may play an important role in bone physiology.

Cellular heterogeneity in giant cell tumour of bone (osteoclastoma): an immunohistological study of 16 cases

Sixteen cases of giant cell tumour of bone (osteoclastoma) were analysed by immunohistochemical techniques using various monoclonal antibodies specific for macrophages, monocytic and granulocytic cells, T- and B-lymphocytes and other cell types. The multinucleate osteoclastic giant cells failed to react with the majority of antibodies specific for myeloid cells and HLA-DR. In contrast to previous findings, giant cells in some tumours reacted with a rat, but not mouse, antibody to leucocyte common (CD45) antigen. Macrophages were detected in all tumours, though their numbers varied considerably; small numbers of T- and B-lymphocytes were identified in four of 16 cases. The neoplastic, spindle-shaped, stromal cells were largely unreactive with the monoclonal antibodies used in this study, further supporting the view that they are not the precursors of the characteristic giant cells, nor are they of haemopoietic origin.

Expression of Ia and monocyte-macrophage lineage antigens in giant cell tumor of bone and related lesions

An immunohistochemical study of six giant cell tumors of bone and eight related lesions (aneurysmal bone cyst, fibrous histiocytoma, and giant cell tumor of tendon sheath) was performed using a panel of monoclonal antibodies directed to the Ia and monocyte-macrophage lineage antigens. In all types of lesion, osteoclastlike multinucleate giant cells were negative for both types of antigen, but a proportion of mononuclear cells gave positive reactions. While the possibility that these cells are reactive cannot be excluded, in giant cell tumor and malignant fibrous histiocytoma, their frequency and their morphologic similarity to the rest of the tissue suggest that they may be an intrinsic part of the neoplasm. This finding is consistent with the presumed fibrohistiocytic nature of these tumors.

HLA-DR antigen detection in giant cell lesions

Sixty-six giant cell lesions ranging from inflammatory to neoplastic were evaluated for HLA-DR antigens using formalin/paraffin tissue and a monoclonal antibody labelled by the avidin-biotin peroxidase. HLA-DR antigens were expressed in nearly all lesions, predominantly on round, macrophage-like cells. Granulomatous inflammatory lesions were generally more immunoreactive than non-inflammatory lesions. Multinucleate giant cells were relatively unreactive in non-inflammatory lesions as compared to inflammatory lesions. Determination of HLA-DR expression does not appear to be helpful in discriminating between the various giant cell lesions.

Breast cancer with reactive multinucleated giant cells: report of three cases

We report here three cases of breast cancer with reactive multinucleated giant cells. The patients were among the 605 patients with breast cancer seen in the past 17 years at Tenri Hospital; the incidence of this variety of breast cancer was 0.5%. Enzyme histochemical and electron microscopic examination suggested that the giant cells were of histiocytic origin. However, results of immunohistochemical technique, S-100 protein, lysozyme, nonspecific cross-reacting antigen with carcinoembryonic antigen, alpha-1-antitrypsin, and alpha-1-antichymotrypsin, all currently used as markers of histiocytes, were negative. Because of the rarity of this variety of breast cancer, the biological significance of these unusual findings remains unknown.

An immunohistological study of giant-cell tumour of bone: evidence for an osteoclast origin of the giant cells

Using a panel of monoclonal antibodies against a variety of lymphoid and non-lymphoid antigens the immunohistological staining pattern of giant cells from a case of giant-cell tumour of bone has been compared with that of osteoclasts from the developing ends of fetal long bones. Only EBM-11, an antibody reacting with a wide spectrum of macrophages, stained both osteoclasts and giant cells; stromal cells and osteoblasts did not react. This indicates that osteoclasts and giant cells are phenotypically and presumably functionally similar. It is argued that the osteoclasts and the tumour-derived giant cells in bone are derived from a similar mononuclear precursor.

Monoclonal antibodies to osteoclastomas (giant cell bone tumors): definition of osteoclast-specific cellular antigens

The cellular origin of the osteoclast, the major agent of bone resorption, remains controversial despite the demonstration that osteoclasts form by fusion of mononuclear cells that are ultimately derived from a bone marrow stem cell. One view is that they are the terminally differentiated progeny of mononuclear phagocytic cells. However, we have previously provided evidence, from functional and phenotypic studies of rodent and human osteoclasts, that raises the possibility that osteoclasts form a separate cell lineage from conventional hemopoietic cells and macrophages in particular. In an attempt to elucidate this question, we have used monoclonal antibody techniques to examine the relationship between osteoclasts and other bone marrow-derived cells. By using osteoclasts from osteoclastomas (giant cell tumors of bone) for immunizations, we have produced 11 mouse hybridomas secreting monoclonal antibodies reacting with osteoclasts in normal human fetal bone and a variety of neoplastic and non-neoplastic bone lesions. Eight antibodies in 4 reactivity sets have been shown to recognize membrane antigens, whereas a further 3 react with cytoplasmic determinants. In 7 there is no cross-reactivity with macrophages in a wide range of tissues, thus effectively differentiating between these two cell types. These antibodies will prove useful for the identification of osteoclasts in tissues and in the separation of their circulating precursors, thus allowing an experimental approach to be made to many of the outstanding questions regarding the developmental pathobiology of the osteoclast.

[Immuno-oncologic monitoring of patients with bronchial carcinoma. IV. Aspects of the immunocompetence system]

Some aspects of the immunocompetent system are tested in 84 lung cancer patients at time of diagnosis and during the natural course of the disease. Results show no significant variations for many immunological tests during the course of the neoplasia. Significant alterations are observed in T-lymphocyte and macrophage evaluation. Moreover, some immunological data are related to lung cancer post-surgical survival.

Delineation of four cell types comprising the giant cell tumor of bone. Expression of Ia and monocyte-macrophage lineage antigens

Giant cell tumors of bone dissociated by collagenase digestion were found to be composed of four different cell types defined by morphology, growth in culture, and pattern of staining with monoclonal antibodies. Giant cells comprised an average of 0.8% of the cells recovered, with the remainder consisting of small stromal cells. Of the giant cells, 20-57% expressed Ia antigens, while all lacked IgG Fc receptors and five differentiation antigens associated with mature members of the monocyte-macrophage lineage (M phi S-1, M phi P-9, M phi P-15, M phi S-39, and 63d3). One antigen, M phi U-50, found on early monocytoid forms was expressed on Ia+ giant cells. 6-36% of the remaining stromal tumor cells formed a second subpopulation that assumed either a rounded or elongated shape in culture. These cells bore Ia antigens, IgG Fc receptors, and five antigens of the monocyte-macrophage lineage usually found on blood monocytes. However, these cells differed from monocytes or macrophages in that the antigen M phi R-17 generally found on tissue macrophages was absent, and the M phi U-50 antigen present on more primitive cells was well expressed. A very limited endocytic capacity was demonstrable. A third population of up to 24% of the tumor cells was defined by the presence of intense staining for Ia antigens but the absence of antigens of mature monocytes. A proportion of these cells expressed M phi U-50 and a minority had IgG Fc receptors. The two Ia(+) populations of stromal cells were not identifiable after 2 wk of culture, nor did tumor cells selected for the presence of Ia antigens proliferate in culture. A fourth population of cells lacked Ia and monocyte lineage antigens, but showed pronounced intracellular staining for acid phosphatase. These cells had a distinctive plump epitheloid to fibroblastoid morphology and were readily established in long-term culture where they gave rise to large multinuclear Ia(-) cells containing acid phosphatase. The possibility is discussed that the cell types of these tumors relate to various stages in the development of osteoclasts from precursors in the mononuclear phagocyte lineage.

[Clinico-immunological studies of 32 cases of bone tumors]

We have studied 32 patients with different bone neoplasias. 18 had osteogenic sarcoma. Clinical and immunological observations led us to consider our results as a general approach to the problem. No specific conclusions can be made. We describe 3 patients treated with levamisole therapy and two with transfer factor. In single patients some useful observations are connected about relationship between treated and non-treated patients.

Circulating immune complexes in patients with bone tumours

Sera from 62 patients with osteogenic sarcoma and 12 with malignant giant-cell tumour were tested for the presence of immune complexes by the 125I-Clq binding assay. Elevated serum Clq binding activity was found in 67.7% of the osteogenic sarcoma patients and in 75% of the giant-cell tumour patients. These results were compared with those obtained with five sera from patients with benign bone tumours and 20 sera from normal young donors. In the last two groups, the incidence of elevated Clq-binding activity was 0% and 5%, respectively. In some patients with giant-cell tumours, pre- and post-operative serum samples were studied, showing a decrease in test values after tumour resection. Preliminary sequential studies of individual patients indicate that the 125I-Clq binding assay may be useful for monitoring patients with bone tumours.

Macrophages in giant cell tumours of bone

Five giant cell tumours of bone were studied to determine the degree of macrophage infiltration and whether the giant cells expressed the characteristics commonly associated with macrophages, i.e., IgGFc and C3 receptors, phagocytosis and non-specific esterase activity. Macrophages were assessed in trypsin-derived tumour cell suspensions by IgGEAC rosette formation and in frozen sections of tumour by EA adsorption. The percentage of macrophages in cell suspensions from four of the tumours ranged from 11 to 40 per cent. Strong EA adsorption occurred over 35 to 95 per cent. of the tumours' surface and significant non-specific esterase positivity was observed in the tumour sections. The giant cells were receptor negative and non-phagocytic, but a low percentage of them expressed esterase activity. The results strongly suggest that despite the fact that large numbers of macrophages were present in the tumours, the giant cells were derived from cells other than macrophages.

Quantitative immunofluorescence studies of the tumor antigen-bearing cell in giant cell tumor of bone and osteogenic sarcoma

Tumor-associated antigen was found by reacting sera from two patients with giant cell tumor of bone with cells derived from their tumors, using autologous serum as intermediate reactant and fluorescein-conjugated goat anti-human IgG as final reactant. Approximately 40% of the plump, spindle-shaped cells that formed the background stroma of these tumors possessed the antigen; however, it was not present on giant cells. Fluorescence was much greater than that on similarly stained cells from 4 osteogenic sarcomas, suggesting that the antigenic density on cells from giant cell tumor was greater than that on cells from osteogenic sarcoma. Antibodies in sera from giant cell tumor patients and osteogenic sarcoma patients showed specific cross-reactivity. Stromal cells of giant cell tumors were established in culture and retained tumor-associated antigen, whereas giant cells failed to divide and detached from the flask within two weeks. Intensity of fluorescence (antigenic density) decreased with progressive passage levels, but a larger percentage of cells showed fluorescence. At the tenth passage, all cells bore tumor-associated antigen. Cultured cells that were injected s.c. into mice formed progressively growing nodules, the cells of which were morphologically indistinguishable from stromal cells of the original tumor; all cells retained tumor-associated antigen, but antigenic density had decreased to about one-seventh of the value found originally. No giant cells were present in the nodules.

Evidence for fetal antigen in human sarcoma

A common antigen (S(2)), initially thought to be uniquely associated with human sarcomas, has been found to be widely distributed in patients with other tumors as well. Absorption studies with human embryonic tissues suggest that S(2) may be a fetal antigen. The presence of antibody to S(2) in patients with tumors and in their relatives implies a propensity in these individuals for cellular dedifferentiation which may be a prerequisite for malignant transformation.