Juvenile hyaline fibromatosis. A histologic and histochemical study

Histochemical and routine light microscopic studies were performed in nodular skin lesions excised from one patient with juvenile hyaline fibromatosis. The lesions had different times of evolution. Recent lesions showed a high density of fibroblastlike cells embedded in an amorphous matrix of glycoproteins, hyaluronic acid, and small amounts of chondroitin sulfates A and C and of dermatan sulfate. The progressive enlargement of the lesions was due to an increase in the amount of intercellular matrix produced by the cells that progressively displayed a pattern of peripheral stratification. In the older lesions, the matrix was mainly composed by chondroitin sulfates A and C. We suggest that juvenile hyaline fibromatosis represents a disease of the connective tissue with progressive abnormal differentiation to chondroid tissue.     

Juvenile hyaline fibromatosis: two new patients and review of the literature

We report on a sister and a brother (born to normal consanguineous parents) with joint contractures and osteolytic lesions of bones. The sister had also gingival hyperplasia and skin lesions consisting of multiple tumors of the face, nose, palate, ears, and neck. Histologic examination showed findings of juvenile hyaline fibromatosis. The literature is reviewed, and 15 cases already reported are summarized.     

Juvenile hyaline fibromatosis: a case report

Juvenile hyaline fibromatosis (JHF) is a rare, autosomal recessively inherited disorder characterized histologically by deposition of hyaline, collagen like substance aberrantly synthesized by the cells of the connective tissue and deposited within many organs, typically within the skin, gingiva, joints and bones. We report this rare case of Juvenile hyaline fibromatosis in a young boy who presented clinically with multiple papulonodular skin lesions, non tender soft tissue masses over the scalp, face, anterior chest wall, back, periarticular regions of the extremities with restricted mobility of joints and gingival hypertrophy. Calcifications were seen within the tumor shadows in the skull X-Rays. Histopathological study revealed characteristic features consistent with Juvenile hyaline fibromatosis. We report this case in view of its rarity.     

Non-nuchal-type fibroma associated with Gardner's syndrome. A hitherto-unreported mesenchymal tumor different from fibromatosis and nuchal-type fibroma

We describe a unique benign mesenchymal tumor in paraspinal location in a 13-year-old patient with Gardner's syndrome. The Gardner's syndrome in this patient consisted of multiple (more than 100) polyps throughout the entire colon with most in the cecum and rectum, three osteomas in the frontal area of the skull and one in the third right rib, and multiple superficial skin tumors. One of these cutaneous tumors was excised and histologically diagnosed as an epidermal cyst. Both father and uncle of this patient suffered from Gardner's syndrome as well. Microscopically the mesenchymal tumor was histologically different from nuchal type fibroma and fibromatosis. It consisted of a diffusely-growing fibrous mass composed of dense collagenous fibers and relatively numerous, bland-looking, spindle-shaped cells. The collagen fibers had haphazard spacing with no lobular arrangement. The collagen fibers were of a very coarse quality. No entrapment of adipose tissue, skeletal muscle or peripheral nerves was seen in the lesion. Immunohistochemically the tumor was vimentin positive and smooth muscle actin, muscle-specific actin, S-100 protein, cytokeratin and desmin negative.     

Localization of type VI collagen in tissue-engineered cartilage on polymer scaffolds

Together, the chondrocyte and its pericellular matrix have been collectively termed the chondron. Current opinion is that the pericellular matrix has both protective and signalling functions between chondrocyte and extracellular matrix. Formation of a native chondrocyte pericellular matrix or chondron structure might therefore be advantageous when tissue engineering a functional hyaline cartilage construct. The presence of chondrons has not been previously described in cartilage engineered on a scaffold. In this paper, we describe a modified immunochemical method to detect collagen VI, a key molecular marker for the pericellular matrix, and an investigation of type VI collagen distribution in engineered hyaline cartilage constructs. Cartilage constructs were engineered from adult human or bovine hyaline chondrocytes cultured on sponge or nonwoven fiber based HYAFF 11 scaffolds. Type VI collagen was detected in all constructs, but a distinctive, high-density, chondron-like distribution of collagen VI was present only in constructs exhibiting additional features of hyaline cartilage engineered using nonwoven HYAFF 11. Chondron structures were localized in areas of the extracellular matrix displaying strong collagen II and GAG staining of constructs where type II collagen composed a high percentage (over 65%) of the total collagen.     

New progeroid disorder

We report on a 10-year-old Caucasian male with a prematurely aged appearance, delayed bone maturation and dental development, pronounced acro-osteolysis with brachydactyly, and distinctive cutaneous findings including hard, confluent skin lesions with some clinical and histologic resemblance to those of juvenile hyaline fibromatosis (JHF). He also had hyperopia, sensorineural hearing loss, and elevated TSH. Linear growth and intellectual functions were normal. We believe that this patient represents a new progeroid disorder. Am. J. Med. Genet. 69:182–187, 1997. © 1997 Wiley-Liss, Inc.     

Regional variations in the distribution and colocalization of extracellular matrix proteins in the juvenile bovine meniscus

A deeper understanding of the composition and organization of extracellular matrix molecules in native, healthy meniscus tissue is required to fully appreciate the degeneration that occurs in joint disease and the intricate environment in which an engineered meniscal graft would need to function. In this study, regional variations in the tissue-level and pericellular distributions of collagen types I, II and VI and the proteoglycans aggrecan, biglycan and decorin were examined in the juvenile bovine meniscus. The collagen networks were extensively, but not completely, colocalized, with tissue-level organization that varied with radial position across the meniscus. Type VI collagen exhibited close association with large bundles composed of type I and II collagen and, in contrast to type I and II collagen, was further concentrated in the pericellular matrix. Aggrecan was detected throughout the inner region of the meniscus but was restricted to the pericellular matrix and sheaths of collagen bundles in the middle and outer regions. The small proteoglycans biglycan and decorin exhibited regional variations in staining intensity but were consistently localized in the intra- and/or peri-cellular compartments. These results provide insight into the complex hierarchy of extracellular matrix organization in the meniscus and provide a framework for better understanding meniscal degeneration and disease progression and evaluating potential repair and regeneration strategies.     

Anaplastic carcinoma of the thyroid with sclerohyaline nodules

Sclerohyaline nodules, resembling deposits of amyloid, were noted in 3 cases of anaplastic thyroid carcinoma (ATC). All 3 patients were elderly, and 2 had good outcomes. Histologically, the nodules were dispersed throughout typical areas of ATC and formed the dominant histologic feature in these areas. The nodules were paucicellular and surrounded by both ATC and chronic inflammatory cells, including prominent numbers of eosinophils. Other areas of the stroma had a more keloidal appearance with minor myxoid foci. The hyaline nodules were negative for calcitonin, amyloid A, type IV collagen, and laminin. We regard these nodules as a response of the extracellular matrix to infiltrating ATC.     

Selective progesterone receptor modulator asoprisnil down-regulates collagen synthesis in cultured human uterine leiomyoma cells through up-regulating extracellular matrix metalloproteinase inducer

BACKGROUND: A recent clinical trial demonstrated that selective progesterone receptor modulator asoprisnil is effective in reducing uterine leiomyoma volume. We investigated the effects of asoprisnil in vitro on the expression of the extracellular matrix (ECM)-remodeling enzymes and collagens in cultured leiomyoma and matching normal myometrial cells. METHODS: The expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMPs) and collagens were assessed by western blot analysis. RESULTS: Untreated cultured leiomyoma cells had significantly lower EMMPRIN (P < 0.05), MMP-1 (P < 0.05) and membrane type 1-MMP (MT1-MMP) (P < 0.01) protein contents, but significantly higher TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.05) and type III (P < 0.01) collagen protein contents compared with untreated cultured myometrial cells. Treatment with asoprisnil at concentrations > or =10(-7) M for 48 h significantly (P < 0.05) increased EMMPRIN, MMP-1 and MT1-MMP protein contents, and decreased TIMP-1 (P < 0.05), TIMP-2 (P < 0.01), type I (P < 0.01) and type III (P < 0.05 at 10(-7) M; P < 0.01 at 10(-6) M) collagen protein contents in cultured leiomyoma cells compared with control cultures. However, asoprisnil treatment did not affect the protein contents of ECM-remodeling enzymes and collagens in cultured myometrial cells. CONCLUSIONS: These results suggest that asoprisnil may reduce collagen deposit in the ECM of cultured leiomyoma cells through decreasing collagen synthesis and enhancing the expression of EMMPRIN, MMPs and TIMPs without comparable effects on cultured myometrial cells.     

Immunohistochemical characterization of extracellular matrix components of granulosa cell tumor of ovary

In order to clarify the characteristics of granulosa cell tumors of the ovary, extracellular matrix components were investigated by immunohistochemical techniques. Twenty-three granulosa cell tumors (GCT; eight juvenile and 15 adult type) were studied in comparison with non-neoplastic granulosa cells of human ovaries. In all 23 cases of GCT, chondroitin 6-sulfate proteoglycan revealed with antibody 3B3 was characteristically observed in the extracellular matrix in the solid nest, as well as in microfollicles. In the juvenile cases, the extracellular matrix also contained large proteoglycan (PG) revealed with antibody 2B1. Macrofollicles as well as micro-follicles contained PG chondroitin 6-sulfate side chains with a significant amount of chondroitin 4-sulfate. By biochemical analysis using high pressure liquid chromatography, it was also found that disaccharide composition of glycosaminog-lycan fractions extracted from granulosa cell tumor tissues consisted mainly of 2-acetamide-2-deoxyl-3-0-(β-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (δ Di-6S). The characteristic feature of granulosa cell tumors is the accumulation of chondroitin sulfate PG, especially chondroitin 6-sulfate PG, which may be synthesized by the tumor cells themselves. Immunohistochemical characterization of the extracellular matrix components (collagen, laminin, heparan sulfate PG, chondroitin 4-sulfate PG) was also studied in relation to chondroitin 6-sulfate PG localization.     

Ⅰ型胶原膜、胞外基质提取物膜体外构建人工真皮能力比较

比较Ⅰ型胶原与胞外基质(extracellularmatrix,EM)提取物冻干后形成的膜(EM膜)在体外构建人工真皮的能力,以选择一种更有利于人工真皮形成的支架材料。方法分别使用小牛真皮部分提取的Ⅰ型胶原蛋白和胞外基质提取物冻干后制备基质网架,植入皮肤成纤维细胞,形成人工真皮。用扫描电镜观察I型胶原膜和EM膜的表面形态结构;选取不同的时间点,对种植于两种支架材料上的细胞进行计数,并利用间接ELISA方法检测人工真皮复合物中的细胞Ⅰ型胶原分泌情况,通过统计学的分析手段,对细胞的生长情况做出判断;用组织学方法观察人工真皮的形成情况。结果扫描电镜观察结果,两种膜在外观形态上无明显差异;细胞在EM膜上的增殖速度较Ⅰ型胶原膜快;ELISA分析显示,EM-细胞复合物中的成纤维细胞能够分泌更多的Ⅰ型胶原;与Ⅰ型胶原膜相比,EM在培养液中的降解更为缓慢,种植后的成纤维细胞在EM膜上生长旺盛,细胞层次明显多于前者,形成了较为明显的真皮样组织。结论EM膜适于成纤维细胞的生长,体外降解速率慢,是一种较Ⅰ型胶原膜更为理想的真皮支架材料。     

Differentiation Capacity of Human Chondrocytes Embedded in Alginate Matrix

Healing capacity of cartilage is low. Thus, cartilage defects do not regenerate as hyaline but mostly as fibrous cartilage which is a major drawback since this tissue is not well adapted to the mechanical loading within the joint. During in vitro cultivation in monolayers, chondrocytes proliferate and de-differentiate to fibroblasts. In three-dimensional cell cultures, de-differentiated chondrocytes could re-differentiate toward the chondrogenic lineage and re-express the chondrogenic phenotype. The objective of this study was to characterize the mesenchymal stem cell (MSC) potential of human chondrocytes isolated from articular cartilage. Furthermore, the differentiation capacity of human chondrocytes in three-dimensional cell cultures was analyzed to target differentiation direction into hyaline cartilage. After isolation and cultivation of chondrogenic cells, the expression of the MSC-associated markers: cluster of differentiation (CD)166, CD44, CD105, and CD29 was performed by flow cytometry. The differentiation capacity of human chondrocytes was analyzed in alginate matrix cultured in Dulbecco’s modified eagle medium with (chondrogenic stimulation) and without (control) chondrogenic growth factors. Additionally, the expression of collagen type II, aggrecan, and glycosaminoglycans was determined. Cultivated chondrocytes showed an enhanced expression of the MSC-associated markers with increasing passages. After chondrogenic stimulation in alginate matrix, the chondrocytes revealed a significant increase of cell number compared with unstimulated cells. Further, a higher synthesis rate of glycosaminoglycans and a positive collagen type II and aggrecan immunostaining was detected in stimulated alginate beads. Human chondrocytes showed plasticity whilst cells were encapsulated in alginate and stimulated by growth factors. Stimulated cells demonstrated characteristics of chondrogenic re-differentiation due to collagen type II and aggrecan synthesis.     

Extracellular matrix globules in renal oncocytoma

Extracellular hyaline globules resulting from abnormal accumulation of matrix components have been described in several pathological conditions, including renal tumors. We studied 16 renal oncocytomas and observed these bodies in 11 of them. In these tumors, they showed a homogeneous texture as well as roundish, smooth contours, and were easily detected in hematoxylin-eosin sections in five cases. PAS staining greatly facilitated the identification of globules in the remaining six cases, where they were fewer in number. Immunohistochemically, they appeared to be composed primarily of basement membrane material, being strongly reactive to antibodies for type IV collagen, laminin, and heparan sulphate proteoglycan. In addition, a weak immunoreactivity for type I and type III collagen, and fibronectin was observed in some cases, whereas no globule stained for tenascin. We also analyzed 89 renal cell carcinomas, and found somewhat similar bodies in 10 of them. However, they were more scanty in the latter tumors, and displayed a more irregular configuration with granular or smudged contours. We conclude that, although the mere presence of extracellular hyaline globules does not justify a distinction between renal oncocytoma and renal cell carcinoma, the detection of a large number of well-demarcated, roundish extracellular bodies with smooth contours suggests renal oncocytoma.     

Temporal and spatial localization of type I and II collagens in human thyroid cartilage

Thyroid cartilages of various ages were investigated by immunofluorescence staining for localization of the fibrillar collagen types I and II in order to understand the tissue remodeling occurring during the mineralization and ossification of thyroid cartilage. In fetal and juvenile thyroid cartilages, type I collagen was restricted to the inner and outer perichondrium, while type II collagen was localized in the matrix of hyaline cartilage. However, in advanced ages, type I collagen was also localized in the pericellular and in the interterritorial matrix of intermediate and central chondrocytes of thyroid cartilage. The matrix of peripheral chondrocytes was negative for type I collagen. This suggests that some chondrocytes in thyroid cartilage undergo a differentiation to type I collagen-producing chondrocytes. At the beginning of ossification, bone-related type I collagen was chiefly detected in the central cartilage layer, but was never deposited first from the perichondrium in the direction to the subperichondrial cartilage. This observation confirmed previous findings showing that osteogenesis mainly follows an endochondral ossification pattern. Interterritorial matrix failed to react with the type II collagen antibody in men from the beginning of the third decade, and later still in women, even after treatment with hyaluronidase. These observations indicate that major matrix changes occur faster in male than in female thyroid cartilage.Dedicated to Professor Dr. W. Kühnel on the occasion of his 60th birthday     

The virus susceptibility of skin-derived fibroblasts from families with insulin-dependent diabetes mellitus

We have studied the growth of eight different viruses on skin fibroblasts from three families each having one or more diabetic members and appropriate controls. The haplotypes of all of the family members had been previously characterized. In addition, we have investigated the growth of mumps virus on the lymphoblast cultures from four families of the same type. Our results show no difference between the growth of these viruses in cells derived from juvenile diabetics and cells derived from nondiabetic siblings and parents even when the haplotypes were identical. However, we noted a striking resistance of human skin fibroblast cultures from both normal and diabetic individuals to Coxsackie B virus infection.     

Differentiation of a fibrin gel encapsulated chondrogenic cell line

Hyaline cartilage has very limited regenerative capacity following damage. Therefore engineered tissue substitutes have been the focus of much research. Our objective was to develop a fibrin-based scaffold as a cell delivery vehicle and template for hyaline cartilage regeneration, and compare its cellular properties against monolayer and pellet culture for chondrogenic cells. The chondrogenic precursor cell line, RCJ 3.1C5.18 (C5.18), was chosen as a test system for evaluating the effect of various culture conditions, including cell encapsulation, on articular chondrogenic cell differentiation. The C5.18 cells in monolayer showed elevated expression of collagen II, an articular chondrogenic marker, but also markers for fibrocartilage differentiation (collagen I and versican) when cultured with chondrogenic medium as compared to basic maintenance medium. Pellets of C5.18 cells cultured in chondrogenic medium were histologically more organized in structure than pellets cultured in control maintenance medium. The chondrogenic medium cultured pellets also secreted an extracellular matrix that was comprised of type II with very little type I collagen, indicating a trend towards a more hyaline-like cartilage. Moreover, when cultured in chondrogenic medium, fibrin-encapsulated C5.18 cells elaborated an extracellular matrix containing type II collagen, as well as aggrecan, which are both components of hyaline cartilage. This indicated a more articular-like chondrogenic differentiation for fibrin encapsulated C5.18 cells. The results of these experiments provide evidence that the C5.18 cell line can be used as a tool to evaluate potential scaffolds for articular cartilage tissue engineering.     

Localization of type I and II collagen during development of human first rib cartilage

The localization of fibrillar type I and II collagen was investigated by immunofluorescence staining with specific antibodies in order to obtain a better understanding of tissue remodelling during the development of first rib cartilage. In childhood and early adolescence type I collagen was found to be restricted to the perichondrium of first rib cartilage, while type II collagen was localized in the matrix of hyaline cartilage. However, in advanced age type I collagen was also found in the territorial matrix of intermediate and central chondrocytes of first rib cartilage. The matrix of subperichondrial chondrocytes was negative for type I collagen. This suggests that some chondrocytes in first rib cartilage undergo a modulation to type I collagen-producing cells. The first bone formation was observed in rib cartilages of 20- to 25-year-old adults. Interestingly, the ossification began peripherally, adjacent to the innermost layer of the perichondrium where areas of fibrocartilage had developed. The newly formed bone matrix showed strong immunostaining for type I collagen. Fibrocartilage bordering peripherally on bone matrix revealed only a faint staining for type I collagen, but strong immunoreactivity to type II collagen. The interterritorial matrix of the central chondrocytes failed to react with the type II collagen antibody, in both men and women, from the end of the second decade. These observations indicate that major matrix changes occur at the same time in male and female first rib cartilages. Thus, our findings indicate that ossification in human first rib cartilage does not follow the same pattern as that observed in endochondral ossification of epiphyseal discs or sternal cartilage.     

Inhibition of type I procollagen synthesis by damaged collagen in photoaged skin and by collagenase-degraded collagen in vitro

Type I and type III procollagen are reduced in photodamaged human skin. This reduction could result from increased degradation by metalloproteinases and/or from reduced procollagen synthesis. In the present study, we investigated type I procollagen production in photodamaged and sun-protected human skin. Skin samples from severely sun-damaged forearm skin and matched sun-protected hip skin from the same individuals were assessed for type I procollagen gene expression by in situ hybridization and for type I procollagen protein by immunostaining. Both mRNA and protein were reduced ( approximately 65 and 57%, respectively) in photodamaged forearm skin compared to sun-protected hip skin. We next investigated whether reduced type I procollagen production was because of inherently reduced capacity of skin fibroblasts in severely photodamaged forearm skin to synthesize procollagen, or whether contextual influences within photodamaged skin act to down-regulate type I procollagen synthesis. For these studies, fibroblasts from photodamaged skin and matched sun-protected skin were established in culture. Equivalent numbers of fibroblasts were isolated from the two skin sites. Fibroblasts from the two sites had similar growth capacities and produced virtually identical amounts of type I procollagen protein. These findings indicate that the lack of type I procollagen synthesis in sun-damaged skin is not because of irreversible damage to fibroblast collagen-synthetic capacity. It follows, therefore, that factors within the severely photodamaged skin may act in some manner to inhibit procollagen production by cells that are inherently capable of doing so. Interactions between fibroblasts and the collagenous extracellular matrix regulate type I procollagen synthesis. In sun-protected skin, collagen fibrils exist as a highly organized matrix. Fibroblasts are found within the matrix, in close apposition with collagen fibers. In photodamaged skin, collagen fibrils are shortened, thinned, and disorganized. The level of partially degraded collagen is approximately 3.6-fold greater in photodamaged skin than in sun-protected skin, and some fibroblasts are surrounded by debris. To model this situation, skin fibroblasts were cultured in vitro on intact collagen or on collagen that had been partially degraded by exposure to collagenolytic enzymes. Collagen that had been partially degraded by exposure to collagenolytic enzymes from either bacteria or human skin underwent contraction in the presence of dermal fibroblasts, whereas intact collagen did not. Fibroblasts cultured on collagen that had been exposed to either source of collagenolytic enzyme demonstrated reduced proliferative capacity (22 and 17% reduction on collagen degraded by bacterial collagenase or human skin collagenase, respectively) and synthesized less type I procollagen (36 and 88% reduction, respectively, on a per cell basis). Taken together, these findings indicate that 1) fibroblasts from photoaged and sun-protected skin are similar in their capacities for growth and type I procollagen production; and 2) the accumulation of partially degraded collagen observed in photodamaged skin may inhibit, by an as yet unidentified mechanism, type I procollagen synthesis.     

Intracellular collagen and fibronexus in fibromatosis and other fibroblastic tumors

Myofibroblasts are mesenchymal cells with combined function and structure for contraction and collagen synthesis. They are found in reparative responses, nodular fasciitis, fibromatosis, and myofibroblastic sarcoma. Ultrastructurally, myofibroblasts are characterized by a specialized cell surface structure called the fibronexus (FNX). In addition, intracellular collagen fibers (ICF) have been described in nodular fasciitis and fibromatosis, but their origin and nature are still controversial. The aim of the present work was, first, to assess the frequency of FNX and ICF in proliferative myofibroblastic conditions compared to diverse mesenchymal tumors with spindle-shaped cells, and, second, to determine what kind of organelles contain ICF and if they are related to phagocytosis or cell synthesis. Forty-two cases of aggressive fibromatosis and 11 of nodular fasciitis (group A) were compared to 82 spindle-cell mesenchymal tumors of diverse nature (group B) by electron microscopy study. The presence and frequency of FNX and ICF was compared in both groups, and the organelles containing ICF were recorded. FNX and ICF were constantly found in group A (69.8 and 84.9%, respectively), and rarely in group B (0 and 5.12%, respectively). Most frequently ICF were contained in tunnels and phagolysosomes, but also were found in Golgi vesicles and cisternae of rough endoplasmic reticulum. In the majority of cases (75%), ICF were similar to collagen fibers of the extracellular space, but in some cases (22.5%), they were in dissimilar stages of fibrogenesis. Fibromatosis and nodular fasciitis are characterized by proliferation of myofibroblasts and constantly show FNX and ICF. These structures are rarely found in other mesenchymal tumors. The ICF are found in organelles of digestion and also in others related to synthesis and transport.     

Extracellular matrix in preneoplastic lesions and early cancer of the lung

Characterization of preneoplastic lesions mainly concentrated on cellular, nuclear and epithelial atypias. The extracellular matrix was almost neglected, although malignant tumour cells interact with extracellular matrix molecules during tumour invasion. Until now systematic investigations of extracellular matrix components in preneoplastic lesions and early stages of lung cancer are lacking. 150 preneoplastic lesions, 10 specimens of early cancer and 30 specimens of normal bronchial mucosa were examined by means of immunofluorescence microscopy. The distribution of collagen type I and III and the non-collagenous glycoproteins laminin and fibronectin have been investigated by an indirect immunohistochemical method. With an increasing degree of preneoplasia an increased matrix disarrangement of the basement membrane zone could be observed. In severe dysplasia and carcinoma in situ neosynthesis of collagen type III and especially laminin in close association to neoangiogenesis could be demonstrated besides a disintegration of extracellular matrix components. In early lung cancer numerous laminin positive basement membrane like structures are situated around tumour cells. An enhanced deposition of collagen type I and III fibres could be demonstrated around tumour cell islets. The results indicate a partial loss of function in preneoplastic basal cells in cases of dysplasia and carcinoma in situ. In early stages of invasive squamous cell carcinoma of the bronchus, extracellular matrix components obviously could be produced by tumour cells.