Immunohistochemical and biochemical studies on the collagenous proteins of human osteosarcomas

Osteosarcoma of the jaws: a 30-year retrospective review

OBJECTIVE

This article reviews osteosarcomas of the jaws referred to the Department of Oral Pathology, Eastman Dental Institute, for histologic diagnosis during the 30 years from 1968 to 1998, to compare the clinical behavior of the tumors, to assess how they differ from the reported characteristics of tumors from other sites, and to report on observations of clinical and diagnostic significance.

STUDY DESIGN

The clinical, radiographic, and histopathologic records of 25 patients were obtained for retrospective review. Supportive and follow-up clinical and histopathologic material was obtained from the referring clinicians.

RESULTS

The mean age of presentation of the primary lesions was 36. 9 years (range, 10-87 years) with a slight female predilection. The most common presenting features were swelling, pain, ulceration, or a neurologic deficit. The radiographic appearance of the lesions was mixed with areas of radiopacity and radiolucency. Histologically, the lesions ranged from those dominated by immature bony trabeculae separated by a cytologically bland stroma to high-grade, cellular lesions with regions of marked atypia and mitotic activity. Most had areas of chondroid formation, in addition to neoplastic osteoid. The main complication was local recurrence. Metastasis was rare and occurred as a solitary process or at a late stage in the disease progression. This was in contrast to lesions metastatic to the jaws, which were higher grade in appearance and had metastasized widely, early in the disease process. Primary osteosarcoma occurring in patients with a history of radiotherapy was typically more aggressive.

CONCLUSION

Primary osteosarcomas of the jaws are a group of lesions distinct from those occurring in the long bones. Osteosarcomas of the jaw arising in a former radiation field may be a discrete group of lesions with a more aggressive behavior pattern.

Loss of type VI collagen in experimental and most spontaneous human fibrosarcomas

Expression of type VI collagen, an adhesive protein of mesenchymal tissues, is significantly down-regulated upon viral transformation of fibroblasts. Likewise, most cell lines derived from spontaneous mesenchymal tumors, including fibrosarcomas, rhabdomyosarcomas, leiomyosarcomas, chondrosarcomas and liposarcomas, do not synthesize type VI collagen because they are not capable of expressing all 3 of the polypeptide chains required for the assembly of a functional heterotrimeric molecule. When injected into nude mice, neither fibrosarcoma cells (HT1080) nor rhabdomyosarcoma cells (A204) initiate the synthesis of type VI collagen, suggesting that the inhibition is not caused by deficiency of a paracrine factor. Immuno-histochemical studies further illustrate that 15 of 17 spontaneous adult fibrosarcomas lack type VI collagen in the tumor stroma. The absence of this important adhesion protein may contribute to tumorigenicity, invasiveness and/or metastasis of mesenchymal tumor cells.

De-differentiated chondrosarcoma is not a 'de-differentiated' chondrosarcoma

AIMS

De-differentiated chondrosarcoma is characterized by the presence of two distinct chondroid and nonchondroid tumour portions. The aim of our study was to investigate the distribution of extracellular matrix components in this tumour entity and thus to shed light on its histogenetic origin.

METHODS AND RESULTS

Histochemical and immunohistochemical analyses were performed for collagen subtypes I, II, III and VI and cartilage proteoglycans in three samples of de-differentiated as well as conventional chondrosarcomas (various grades). In the chondroid tumour areas of de-differentiated chondrosarcoma, typical cartilage matrix components could be detected similar to chondroid areas of grade 1 and 2 conventional chondrosarcomas. In contrast, the tumour matrix of the nonchondroid portions of de-differentiated chondrosarcomas contained matrix molecules which are typical for fibroblastic tissue. This matrix composition was not identical with less differentiated (nonchondroid) areas of grades 2 and 3 conventional chondrosarcomas.

CONCLUSIONS

Our results confirm the chondroid nature of the differentiated portion of de-differentiated chondrosarcoma and indicate a nonchondrocytic nature of the nonchondroid portion. De-differentiated chondrosarcoma should not be considered as a 'de'-differentiated chondrosarcoma (grade 4 neoplasm), but as a tumour entity showing two types of mesenchymal differentiation.

Tissue matrix protein expression in human osteoblasts, osteosarcoma tumors, and osteosarcoma cell lines

Treatment for osteosarcoma is problematic because there are no prognostic markers. Diagnosis is primarily limited to cytologic grading. Oncogenesis alters cell structure therefore osteoblast tissue matrix proteins (extracellular matrix, cytoskeletal, intermediate filament, and nuclear matrix proteins), components of the cell substructure, are candidates for osteosarcoma markers. Structural proteins of the extracellular matrix, e.g. the collagens, are useful for diagnosis but not for tumors that produce little osteoid. To identify principal cellular tissue matrix proteins that distinguish normal from transformed human osteoblasts, their expression in normal osteoblasts, two osteosarcoma cell lines, and three primary osteosarcoma tumors were compared. The tumors were graded as (i) intermediate, (ii) high, and (iii) high grade recurrent. The 1-D SDS/PAGE profiles of the major components of the nuclear matrix and intermediate filament fractions from normal osteoblasts did not vary with biopsy site, age, or sex of patients. These profiles included known cytoskeletal proteins and OB250, a approximately 250 kD protein(s) observed in the intermediate filament fraction. A loss of protein bands, including OB250, was observed in the osteosarcoma cell lines and tumors. The intermediate and high grade tumors exhibited nearly identical protein profiles including potential tumor-specific proteins and collagen, consistent with the presence of intracellular collagen fibers in osteosarcoma. A microsequence was obtained for OT25, a novel low molecular weight protein observed in osteosarcoma cell lines. Fibrinogen gamma-chain, a protein that mediates cell adhesion was recovered from the high grade recurrent tumor.

Stromal differentiation and architecture of the human umbilical cord

In order to assess the characteristics of its stromal cells and the distribution of extracellular matrix proteins, we investigated, immunohistochemically and ultrastructurally, term, first and second trimester human umbilical cords. A differential distribution pattern of the various cytoskeletal proteins of stromal cells and extracellular matrix proteins was observed in different zones of the stroma, the subamniotic stroma, Wharton's jelly, and the vessels' adventitia. All three zones showed immunoreactivities for collagen types I, III and VI and for basement membrane molecules such as collagen type IV, laminin and heparan sulphate proteoglycan. Immunoreactivities for these extracellular matrix molecules were observed around cleft-like territories (stromal clefts) in the Wharton's jelly which were occupied by homogeneous ground substance but void of collagen fibrils and basal lamina molecules. Moreover, between the stromal clefts, slender cells were found which immunohistochemically and ultrastructurally corresponded to various stages of myofibroblastic differentiation. In earlier stages of gestation, stromal cells with a less complex expression pattern prevailed. The stromal clefts and the contractile cells together might serve as a system regulating the turgor of the cord.

Osteosarcoma versus malignant fibrous histiocytoma of bone in patients older than 40 years. A clinicopathologic and immunohistochemical analysis with special reference to malignant fibrous histiocytoma-like osteosarcoma

BACKGROUND

It is often difficult to discriminate between osteosarcoma and malignant fibrous histiocytoma (MFH) of bone, especially in older patients because of the clinical similarities, including the lytic radiologic appearance. A histologic analysis of MFH-like osteosarcoma, which closely resembles MFH of bone both clinically and radiologically, has not yet been conducted thoroughly, and therefore this issue remains controversial.

METHODS

Using clinicopathologic and immunohistochemical techniques, the authors studied 24 cases of osteosarcoma arising in patients older than 40 years of age and compared them with 20 cases of MFH of bone from similarly aged patients.

RESULTS

Radiography revealed that 68.2% of the osteosarcoma cases were predominantly lytic, whereas all cases of MFH of bone showed either a predominantly or purely lytic pattern. Histologically, osteosarcoma was subclassified as conventional osteoblastic (54.2%), MFH-like (29.2%) containing various amounts of tumor osteoid and/or bone in each of the cases, and conventional fibroblastic (4.2%), whereas all the cases of MFH of bone had a storiform-pleomorphic pattern. Immunohistochemically, no overexpression of p53 protein was found in MFH-like osteosarcoma, whereas it tended to occur more frequently in osteoblastic osteosarcoma (66.7%) and MFH of bone (50.0%). The Ki-67 labeling index was significantly lower in MFH-like osteosarcoma than in MFH of bone. The 5-year survival rate was 18.2% in patients with osteoblastic osteosarcoma, 66.7% in patients with MFH-like osteosarcoma, and 21.5% in patients with MFH of bone. A significant difference in the survival curve was observed between osteoblastic and MFH-like osteosarcoma.

CONCLUSIONS

It is proposed that MFH-like osteosarcoma, which shows characteristically different clinical and histologic features from that of conventional osteosarcoma, thus may be considered a variant of osteosarcoma.

Immunohistochemical identification of proteoglycan form of macrophage colony-stimulating factor on bone surface

Several studies using op/op mice have shown that macrophage colony-stimulating factor (M-CSF) was necessary for osteoclast formation in vivo. Previously we reported that osteoblastic cells produced two molecular forms of M-CSF; one is an 85-kDa M-CSF, and the other is a proteoglycan form of M-CSF (PG-M-CSF) which has a binding affinity for bone-derived collagens and is extractable from human bone. In this study, we performed immunostaining of human bone using a newly established anti-PG-M-CSF antibody, and showed positive staining PG-M-CSF, probably produced by bone lining cells, on the bone surface. This observation suggests that the bone surface is suitable for osteoclast formation because of the presence of PG-M-CSF.

Immunohistochemical study on collagenous proteins and biophysical analysis of crystals in extraskeletal chondroma

The immunohistological distribution of collagen types I, II, III, and VI in five cases of extraskeletal chondroma was examined and compared with that in six cases of enchondroma. In addition, the composition of crystals deposited in three cases of extraskeletal chondroma were biophysically analyzed with special attention to the relationship between the collagen types of the matrix and the crystal deposition. In extraskeletal chondroma, immunoreactivity of type II collagen in the extracellular matrix and type VI collagen in the pericellular area, which were strongly and diffusely recognized in the normal hyaline cartilage and enchondroma, was diminished. Instead, additional types of collagen, types I and III, were demonstrated in the matrix. Electron roentgenographic microanalysis and infrared light spectroscopic analysis revealed that calcium pyrophosphate dihydrate (CPPD) was included in the crystals of extraskeletal chondroma. CPPD crystals were observed in/around collagen types I and III. The possible relationship between the difference of collagen composition in the matrix and the CPPD crystal deposition is discussed.

New aspects of cell biology in osteosarcoma

Among the solid tumors of childhood and adolescence, osteosarcoma (OS) represents the most prominent example of efficient aggressive chemotherapy with secondary surgical therapy. A specific subclassification of the tumor is indispensable and must include recent results of cell biology. The co-distribution of different collagen types I-VI reflects the diverse differentiation of osteosarcoma cells, supporting the concept of a pluripotent mesenchymal cell to be the stem cell of the tumor. In contrast, osteonectin (SPARC) may not be considered as a reliable marker for osteosarcoma. The experience of special proteins being secreted by osteosarcoma cells is rather limited. Detailed molecular biological studies are still lacking. A loss of alleles on chromosome 17, particularly in the defined region 17p 13, can be observed in more than 75% of all OS, suggesting the contribution of a tumor suppressor gene, p53, located in that region. It is a 53 kd nucleophosphoprotein binding the major transforming protein, the large T antigen of Simian Virus 40. Immunohistological results showed positive staining with the antibody Pab 240 in 13 of 18 cases. In one osteoblastic OS, a novel splice mutation resulting in a fusing of exon 5 directly to exon 7 was detected. RB1 gene is also of major importance for the tumorigenesis of OS. The multidrug resistance (mdr) is associated with a membrane-bound channel-forming transport protein, the P-glycoprotein. It is a conserved plasma membrane component of about 170 kd. Both the human isoforms mdr 1 and mdr 3 are localised in the long arm of chromosome 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Composition and posttranslational modification of individual collagen chains from osteosarcomas and osteofibrous dysplasias

The composition of collagen was analyzed and the degree of lysyl hydroxylation of individual collagen chains was determined in four osteosarcomas and two osteofibrous dysplasias. In addition, the tumor proliferation (number of mitoses, proliferating-nuclear-antigen-positive cells, MIB) as well as the response to chemotherapy (morphological regression grade) were checked. All tumors contained a high proportion of collagen III and, in all but one osteosarcoma, pepsin-extracted collagens I and III were overmodified. Furthermore, the proportion of diglycosides in collagen I was about four times higher than in controls. The collagen composition and modification resembled those of bones at early stages of human development. One osteosarcoma and both osteofibrous dysplasias were in the normal range of lysyl hydroxylation. There was no correlation between the collagen properties and the histopathological marker of tumor proliferation.

Inhibitory effects of adhesion oligopeptides on the invasion of squamous carcinoma cells with special reference to implication of alpha v integrins

We studied invasion-related adhesion events in vitro using three squamous carcinoma cell lines (HSC-3), poorly differentiated type; OSC-19, well-differentiated type; and KB cells, undifferentiated type). An in vitro invasion assay through matrigel in the transwell chamber revealed that HSC-3 cells were most invasive, OSC-19 cells moderately invasive and KB cells least invasive. Inhibition assay of invasion using synthetic peptides RGD, RGDV, RGDS, RGDT, IKVAV and YIGSR, showed that invasion of the three cell lines was significantly inhibited by RGDV. There were other peptides that inhibited invasion significantly including IKVAV for HSC-3, and RGDS and YIGSR for OSC-19. HSC-3 cells and OSC-19 cells adhered to fibronectin, laminin, vitronectin, and type IV collagen, and KB cells did not adhere to laminin but did to fibronectin, vitronectin and collagen type IV. Pretreatment of cells with RGDV peptide in the attachment assay reduced the ability of these cells to bind to vitronectin and fibronectin more efficiently than pretreatment with RGDS. Anti-alpha v antibodies inhibited adhesion of HSC-3, OSC-19 and KB cells to vitronectin, but anti-beta 1 antibodies did not inhibit adhesion. Immunofluorescent microscopic examinations showed that all cell lines were positive for anti-beta 5 and anti-alpha v antibodies, and only HSC-3 cells were positive for anti-beta 3 antibody. alpha 5 beta 1 was not clearly demonstrated in any of the cell lines. RGDV was the most effective inhibitor of squamous cell carcinoma invasion among the synthetic oligopeptides used in this experiment, and it is suggested that it affects alpha v beta 3- and/or alpha v beta 5-mediated carcinoma cell invasion.

Extracellular matrix of small round cell tumors of childhood: an immunohistochemical study of 67 cases

Sixty-seven childhood tumors were studied immunohistochemically for the extracellular matrix element type IV collagen, laminin, and fibronectin. Tumors included Ewing's sarcoma, primitive neuroectodermal tumor, small cell osteosarcoma, neuroblastoma or ganglioneuroblastoma, rhabdomyosarcoma, and lymphoma. It was found that small cell osteosarcoma was often positive for fibronectin but not type IV collagen or laminin, a new observation. In the lymphomas, matrix proteins were rarely found. Ewing's sarcoma was variably positive for type IV collagen and laminin, but fibronectin was absent. Extracellular laminin and fibronectin were found in one of two cases of primitive neuroectodermal tumor. In neuroblastoma and ganglioneuroblastoma, the matrix components were rarely found. These results, discrepant with findings in cultured cells, may reflect the altered capacity of tumors to produce these proteins in vitro, which suggests that caution should be exercised in drawing conclusions regarding the nature or histogenesis of tumors from data obtained with cultured tumor cells. Embryonal rhabdomyosarcoma frequently contained all matrix elements in the extracellular space and in a dotlike pattern in the cytoplasm; alveolar rhabdomyosarcoma rarely contained these proteins and never exhibited the dotlike pattern. The frequent finding of matrix proteins in embryonal rhabdomyosarcoma but only rarely in alveolar rhabdomyosarcoma and the unique immunostaining pattern in embryonal rhabdomyosarcoma may prove to be a useful adjunct in the diagnosis of childhood tumors.

Chemotherapeutic effect on osteosarcoma on basis of collagen analysis: a proposal of the induction of osteosarcoma differentiation

The authors studied effect of chemotherapy on osteosarcoma by collagen analysis. As a result of this case study we propose the induction of osteosarcoma differentiation by chemotherapy. Treatment of a conventional osteosarcoma with two intra-arterial infusions of cisplatin and the T-12 protocol of Rosen resulted in sclerotic changes and good margination accompanied by the disappearance of the soft-tissue component from the X-rays. More than 90% tumour destruction was histologically demonstrated; tumour bone and osteoid increased after the chemotherapy, and the viable area of the tumour resembled an osteoblastoma. Before the chemotherapy, immunolocalization determined collagen types I and V to be diffusely present in the bone and osteoid. After the chemotherapy, the antibody to type I collagen was diffusely present, but the antibody to type V collagen occurred only on the surface of the increased bone and osteoid as in normal bone. When osteosarcoma cells were treated in vitro with methotrexate or cisplatin, collagen production increased significantly. It is thus believed that tumour cells were directly stimulated with these chemotherapeutic agents to produce collagen. The findings suggested that some anticancer agents might not only be cytotoxic to but also differentiate osteosarcoma cells.

Borderline chondrosarcoma of long and flat bones

We reviewed histological and clinical findings of six cases of borderline chondrosarcoma and examined the expression of collagen types I, II, III, V, and VI by immunohistochemical analysis of these tumors. Borderline chondrosarcoma is defined as a cartilaginous tumor of bone resembling enchondroma on the basis of histomorphology. Clinically the tumor causes intermittent vague pain unrelated to physical activities. On radiographs borderline chondrosarcoma is characterized by evidence of endosteal erosion. We observed local recurrences in two cases treated by intralesional excision and marginal excision, and one of those cases died of inoperable local tumor recurrence. In our histological analysis based on tissue patterns, there were enchondromatous patterns in five cases, and chondrosarcomatous patterns in four cases. In the second recurrent tumor in one case, a chondrosarcomatous pattern was newly observed, and the recurrent tumor was found to be a low-grade chondrosarcoma cytologically in the other case. In the tumor matrix immunoreactivity for collagen types II and VI was predominant, with collagen types I, III, and V showing heterogeneous expression in some cases. In all cases rimming of tumor lobules with collagen types I and V was absent. Immunoreactivity for collagen type II in the cytoplasm of tumor cells was found in four cases and all three recurrent tumors. Borderline chondrosarcoma, as defined by histology, clinical symptoms and radiological appearance, shows a collagen distribution pattern similar to that of low-grade chondrosarcoma. These findings are in accordance with the clinical outcome of borderline chondrosarcoma which parallels that of low-grade chondrosarcoma. Thus borderline chondrosarcoma may be best treated by wide en-bloc excision rather than curettage.

The expression of invasive behavior of differentiated squamous carcinoma cell line evaluated by an in vitro invasion model

In order to elucidate the factors contributory to the expression of invasiveness of oral squamous cell carcinoma, we conducted biochemical and morphological comparisons of well differentiated squamous carcinoma cell line OSC-19 (oral squamous cell carcinoma) and undifferentiated carcinoma cell line KB, both cultured on 3T3 cell-embedded collagen gel (in vitro invasion model). OSC-19 cells invaded 3T3 cell-embedded collagen gel, while KB cells and OSC-19 cells on 3T3 cell-free gel matrix were less invasive. Cultured OSC-19 cells were characterized by lower proliferating activity, lower secretion of laminin and higher secretion of fibronectin than those of KB cells. Although the basement membrane with deposition of laminin and type IV collagen was formed, it was discontinuous at the invasion front. Gelatin zymography and western blotting showed matrix metalloproteinases (MMP), i.e., 72 kDa gelatinase (MMP-2) and 92 kDa gelatinase (MMP-9). Gelatinolytic activity was assayed, and was higher in OSC-19 cells than in KB cells or OSC-19 cells of the 3T3 cell-free model. By immunohistochemical analysis, MMP-2-positive cells were found scattered in both cell lines without any preferential localization, and the positivity for MMP-9 was localized in the invasion front of OSC-19 cells. These results strongly suggest that the invasiveness of squamous cell carcinoma is well correlated with cell-matrix adhesion by fibronectin and with focal elaboration of metalloproteinases, especially MMP-9, which play a major role in degrading the extracellular matrix components.

Expression of epithelial and extracellular matrix protein markers in meningiomas

In an attempt to characterize the dual mesenchymal and epithelial differentiating potential of meningiomas, cryostat sections from 50 meningiomas of diverse histological subtypes were examined immunohistochemically with a panel of markers for epithelial and mesenchymal differentiation. The overall positivities were: keratins 50%, epithelial membrane antigen 94%, human milk fat globules 38%, carcinoembryonic antigen 4% (secretory meningiomas only), desmoplakins 64%, collagen I 82%, procollagen I 96%, collagen III 74%, collagen IV 60%, laminin 54%, fibronectin 98% and vimentin 98%. Such production of keratins was not found in many previous immunohistochemical analyses of meningiomas with paraffin sections. The extracellular matrix proteins were present in a pericellular distribution suggestive of their being produced by the tumour cells. The potential of dual epithelial and mesenchymal differentiation in meningiomas was further examined in seven cases established on short-term cultures. Morphologically, subcultured tumour cells resembled fibroblasts and in five cases revealed similar epithelial and mesenchymal immunohistochemical profiles as for direct tumour immunostaining. In two cases, cells from the primary cultures revealed a fine skeleton of intercellular matrix proteins stainable by immunohistochemical methods, providing further proof that meningioma cells possess the capability to elaborate extracellular matrix proteins, a major mesenchymal function akin to that of fibroblasts.

Immunohistochemical localization of collagenous proteins in cartilaginous tumors: characteristic distribution of type IX collagen

The distinctive tissue localization of collagen types, particularly of type IX collagen in human cartilaginous tumors (10 cases of enchondroma and 15 cases of chondrosarcoma including 3 cases of secondary chondrosarcoma) was examined immunohistochemically using affinity-purified antibodies against types I, II, III, V, VI, and IX collagen, in comparison with that in human fetal cartilage. In fetal cartilage matrix, types II and IX collagen were diffusely distributed, while types I, III, and V collagens were not present. In the matrices of enchondromas and primary chondrosarcomas, types II and IX collagens were also diffusely distributed, but with some areas of irregular type IX collagen deposits. The secondary chondrosarcoma simulated normal fetal cartilage in the distribution pattern of types II and IX collagen, unlike the pattern in primary chondrosarcoma, where types II and IX collagen were decreased and poorly immunostained, whereas non-cartilaginous interstitial collagens (I, III, and V) appeared diffusely in the matrix, increasing with the grade of malignancy. These findings suggest that neoplastic cartilage is characterized initially by an uneven distribution of type IX collagen, prior to any alteration of other types of collagen; the diverse expressions of intercellular components in cartilaginous tumors may be one indicator for malignancy.

Collagenous and basement membrane proteins of chordoma: immunohistochemical analysis

Tissue localization of collagenous and basement membrane proteins in the extracellular matrix of five sacro-coccygeal chordomas and human fetal notochords was examined immunohistochemically to assess the implications for the histogenesis and histological diagnosis of chordoma. Human fetal notochords and conventional chordomas both exhibited basement membrane proteins (such as type IV collagen and laminin) and type VI collagen on the surfaces of cellular cords. Type II collagen, a main structural protein of cartilage, was also present in both tissues. In the chordomas, however, type II collagen was not so widespread as it was in the notochords, and the predominant collagenous protein was type I. In contrast, an altered deposition of these proteins was noticed in a recurrent tumour which, histologically, showed considerable atypia and eventually metastasized to the liver. The characteristic cartilage-type and basement membrane proteins disappeared and unusual collagen types, such as types III and V, appeared in the stroma. The results further support the notochordal origin of chordoma and suggest that the immunohistochemistry of collagenous and basement membrane proteins may be a helpful criterion for the histological diagnosis and prediction of the biological aggressiveness of chordomas.

Chondroblastoma of bone. A clinical, radiological, light and immunohistochemical study

The clinical and morphological findings of 53 chondroblastomas in the files of the Bone Tumour Registry of Westphalia are presented. The mean age of all patients was 19.2 years. The male-to-female ratio was 1.5:1. Forty-two of the tumours (79.8%) were located in the long tubular bones and short tubular bones of the hands and were closely related to the growth plate. Six cases (11.3%) were found in the flat bones, 4 cases (7.5%) in the tarsal bones and 1 case (1.9%) in the craniofacial bones. The characteristic radiological feature of 44 investigated lesions was a mostly eccentric radiolucency with a geographic pattern of bone destruction and matrix calcifications. Periosteal reaction was evident in 9% of the cases. Most tumours demonstrate the typical morphological features of chondroblastoma, but 3 cases resembled a giant cell tumour. In 2 cases a haemangiopericytoma-like growth pattern was observed. Nine of the tumours had an aneurysmal bone cyst-like component. Vascular invasion was seen in 1 case. Immunohistochemically most cells in 30 of the cases and fetal chondroblasts in 3 cases were strongly positive with vimentin and S-100 protein. Collagen type II was positive in the chondroid matrix of the tumours and in fetal cartilage tissue; collagen type VI was present focally around individual tumour cells and was always seen in the chondroid matrix of the lesions and in fetal cartilage. These findings support the cartilaginous nature of these tumours. In paraffin sections, 46.6% of the cases revealed a distinct positive reaction of some tumour cells with the monoclonal cytokeratin antibody KL1 (molecular weight 55-57 kDa). Only 4 of them demonstrated a coexpression with the other monoclonal cytokeratin antibody CK (clone MNF 116, molecular weight 45-56.5 kDa). In paraffin sections all fetal chondroblasts were negative with both cytokeratin antibodies. Frozen sections of 3 tumours showed a strong positive reaction with both cytokeratin antibodies in many chondroblasts, indicating an "aberrant" cytokeratin expression. Osteoclast-like giant cells stained positive with leucocyte-common antigen (LCA) and with the macrophage-associated antibody KP1, but were negative with the other macrophage-associated antibody MAC 387. Recurrence rate was 10.7%. The clinical course of all tumours was benign.

Collagens in human atherosclerosis. Immunohistochemical analysis using collagen type-specific antibodies

This study represents a systematic analysis of the distribution of collagen types in human atherosclerotic lesions. Formalin-fixed, paraffin-embedded aortic tissues of 40 lesions from 16 different individuals ranging in age from 1 month to 84 years were examined immunohistochemically using antibodies to type I, III, IV, V, and VI collagens. Preembedding immunoelectron microscopy was used to simultaneously localize type V and VI collagens within the lesions. Localization of type III collagen was very similar to that of type I, and type VI collagen appeared together with these two types of collagen in the thickened intimas of all stages of the lesion. Type V collagen was not detected in either fatty streaks or the mild intimal thickening of the aortas of children. With advancing age and lesion progression, the immunoreactivity with anti-type V collagen antibody became more intense. Type IV collagen was detected in the basement membrane region of intimal cells. In advanced lesions thick deposits of type IV collagen were found around the elongated smooth muscle cells. Using immunoelectron microscopy, type V collagen was found to be localized to cross-banded collagen fibers, and type VI collagen was found to be localized to beaded filaments present throughout the interstitium of the thickened intima. These findings suggest that collagens preserve the pathophysiological and functional integrity of the vascular wall by providing mechanical support as well as assuring the proper interaction of cells during the formation of atherosclerotic lesions.

Cellular variant of extraskeletal myxoid chondrosarcoma of abdominal wall--a case report with comparative immunohistochemical study on cartilaginous collagenous proteins in various myxoid mesenchymal tumors

A rare cellular variant of recurrent extraskeletal myxoid chondrosarcoma occurring in the right lower abdominal wall of a 70-year-old man, is presented with emphasis on a characteristic distribution pattern of cartilaginous collagen proteins in the stroma. While the primary and the first recurrent tumors showed the typical histology of extraskeletal myxoid chondrosarcoma, the later tumor, which recurred 14 years after the first resection, comprised mostly compact nodules of proliferating anaplastic cells with little mucoid stroma. Some areas presented a hemangiopericytomatous pattern. A few nodules possessed abundant myxoid stroma. Immunohistochemically, type II collagen was demonstrated in the stroma of some cellular areas, and type VI collagen was intensely stained around individual tumor cells both in cellular and myxoid areas. In a comparative immunohistochemical study, the same distribution pattern of cartilaginous collagen proteins was observed only in skeletal myxoid chondrosarcomas, but not in other mesenchymal tumors with abundant myxoid stroma. These findings seem to support the cartilaginous nature of extraskeletal myxoid chondrosarcoma, and will facilitate the differential diagnosis of soft-tissue tumors with myxoid stroma.

Immunophenotypic heterogeneity in osteosarcomas

Eighteen osteosarcomas were studied immunohistochemically. The tumors were classified into the following six histologic subtypes: five osteoblastic, four chondroblastic, four malignant fibrous histiocytoma-like, two telangiectatic, two low-grade central, and one giant cell-rich. Variable amounts of osteocalcin immunoreactivity were found in all tumors. Factor XIIIa-positive cells, which may be of fibrohistiocytic lineage, were present in three tumors of the malignant fibrous histiocytoma-like type, one of the telangiectatic type, one of the low-grade central type, and the tumor of the giant cell-rich type. One tumor of the osteoblastic type showed cytokeratin and epithelial membrane antigen immunoreactivities. The positive reactions for desmin in four tumors, for alpha-smooth muscle actin in 11 tumors, and for type IV collagen in one tumor seemed to indicate myofibroblastic differentiation of some tumor cells. S-100 protein-positive tumor cells were detected not only in all four tumors of the chondroblastic type, but also in three of the osteoblastic type, one of the low-grade central type, and in the tumor of the giant cell-rich type. These immunohistochemical results suggest that osteosarcomas are composed of heterogeneous cell populations, such as those of the osteoblastic, chondroblastic, myofibroblastic, and fibrohistiocytic types, and occasionally also of cells with epithelial features.

Immunohistological study on collagenous proteins of benign and malignant human cartilaginous tumours of bone

The immunohistological distribution of collagen types I, II, III, V and VI in human benign and malignant cartilaginous tumours of bone was examined with regard to their aggressiveness. The matrix of enchondromas consisted of type II collagen distributed diffusely, and type VI predominantly localized in the immediate surroundings of the cells. Types I, III and V collagen were not found. These findings were similar to the distribution of collagenous proteins in normal hyaline cartilage where each lobule was consistently rimmed by types I and V collagen. In grade 1 chondrosarcomas, the main collagenous components of matrix were also types II and VI collagen. Type II was sometimes found in the cytoplasm of tumour cells and type VI tended to lose territorial localization. In addition, type I collagen was demonstrated consistently and type V in some cases. In grade 2 chondrosarcomas, type II collagen was demonstrated not only in the matrix but occasionally in the cytoplasm of tumour cells. Type VI was dispersed in the intercellular areas. The other collagenous proteins such as types I, III and V were also present in the matrix. In grade 3 chondrosarcomas, type II collagen was localized predominantly in the cytoplasm of tumour cells and in the adjacent matrix. Type VI was markedly decreased with complete loss of pericellular distribution, whereas types I, III and V were constantly present in the matrix. Those alterations in the distribution of collagen types correlated well with the aggressive behaviour of the tumours. The findings suggest that distribution of different collagen types in cartilaginous tumours reflects the immaturity of the tumour cells and is a useful indicator of their aggressiveness.

Left ventriculotomy of the heart: tissue repair and localization of collagen types I, II, III, IV, V, VI and fibronectin

The reparative process following left ventriculotomy was investigated immunohistochemically using anti-type I, II, III, IV, V and VI collagen antibodies, and anti-fibronectin antibody. Wound healing began with proliferation of young fibroblasts positive for type I, III and V collagens at the wound margin; vascular granulation tissue then grew into the injured myocardium followed by deposition of fibrous components immunoreactive with type I and III. At 30 days after operation when almost the entire thickness of the myocardium at the wound was replaced by fibrosing granulation tissue, a small cluster of adipocytes appeared around capillaries at the wound margin. The granulation tissue was gradually replaced by the adipose tissue with establishment of a fibrous union at the subendocardium by 90 days. In addition to type I and III collagens, type VI collagen was detected in a fine fibrillary pattern along thick collagen fibre bundles in the fibrous tissue and around the adipocytes. Fibronectin was distributed diffusely in the granulation tissue and gradually decreased with increase of the fibrous components. These results indicate that the ventriculotomy was finally repaired in the form of a fibrous scar, particularly in the endocardium. There was marked infiltration of adipose tissue in the damaged myocardium. Presumably type VI collagen, as well as type I and type III collagens, plays an important role in wound union.