Expression of growth factors and their receptors in adamantinoma of long bones and the implication for its histogenesis

Unraveling molecular signatures in rare bone tumors and navigating the cancer pathway landscapes for targeted therapeutics

Rare cancers (RCs), which account for over 20% of cancer cases, face significant research and treatment challenges due to their limited prevalence. This results in suboptimal outcomes compared to more common malignancies. Rare bone tumors (RBTs) constitute 5-10% of rare cancer cases and pose unique diagnostic complexities. The therapeutic potential of anti-cancer drugs for RBTs remains largely unexplored. Identifying molecular alterations in cancer-related genes and their associated pathways is essential for precision medicine in RBTs. Small molecule inhibitors and monoclonal antibodies targeting specific RBT-associated proteins show promise. Ongoing clinical trials aim to define RBT biomarkers, subtypes, and optimal treatment contexts, including combination therapies and immunotherapeutic agents. This review addresses the challenges in diagnosing, treating, and studying RBTs, shedding light on the current state of RBT biomarkers, potential therapeutic targets, and promising inhibitors. Rare cancers demand attention and innovative solutions to improve clinical outcomes.

Targeting Bone Metastases Signaling Pathway Using Moringa oleifera Seed Nutri-miRs: A Cross Kingdom Approach

Moringa oleifera is a medicinally important plant that has various medical and nutritional uses. Plant miRNAs are a class of non-coding endogenous small RNAs that regulate human-specific mRNA but the mechanistic actions are largely unknown. Here, in this study, we aim to explore the mechanistic action and influence of M. oleifera seed miRNAs on vital human target genes using computer based approaches. The M. oleifera seed miRNAs sequence was taken from published data and identified its human gene targets using a psRNA target analysis server. We identified 94 miRNAs that are able to significantly regulate 47 human target genes, which has enormous biological and functional importance. Out of 47 human targeted genes, 23 genes were found to be associated with PI3K-AKT, RUNX, and MAPK1/MAPK3 signaling pathway which has shown to play key roles in bone metastases during cancer progression. The M. oleifera seed miRNAs hold a strong potential for future research that might uncover the possibility of miRNA-facilitated cross-kingdom regulation and therapeutic targets for bone metastases.

Osteofibrous dysplasia and adamantinoma: A summary of diagnostic challenges and surgical techniques

Osteofibrous dysplasia is an indolent benign fibro-osseous tumor, while adamantinoma is a locally aggressive biphasic malignancy with epithelial and fibro-osseous components. Predominantly arising in the tibial diaphysis of children and young adults, both tumors are resistant to chemotherapy and radiation. Wide surgical resection is regarded as the mainstay of therapy for adamantinoma, and limb-salvage reconstructive procedures can achieve good functional outcomes, albeit with non-negligible rates of complications. This review discusses emerging advances in the pathogenesis, histogenesis, and diagnosis of these entities and presents advantages and limitations of the most common surgical techniques used for their management.

Metastatic Basal Cell Carcinoma of the Skin: A Comprehensive Literature Review, Including Advances in Molecular Therapeutics

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. In Europe, the incidence of BCC ranges from 44.6 to 128 cases per 100,000 inhabitants annually, whereas in the United States, the yearly incidence rate ranges between 500 and 1500. The global incidence has been calculated to be as high as 10 million cases of BCC per year. There are 2 main clinical patterns of BCC-the familial BCC in basal cell nevus syndrome and sporadic BCC. The etiology of cutaneous BCC is usually the result of the interaction between solar ultraviolet radiation and genetic factors. Somatic or germline mutations in the effector components of the hedgehog signaling pathway (ie, PTCH1, PTCH2, SMO or SUFU genes) are responsible for ∼90% of the cases of both sporadic and familial BCC, all causing a constitutive activation of the hedgehog pathway. Cutaneous BCC very rarely metastasizes, and diagnosis in metastatic sites can be very difficult. Metastatic BCC has weakly effective therapeutic options with a poor prognosis until few years ago. In 2012, small-molecule therapies, involving inactivation of the hedgehog signaling pathway, and capable of reducing tumor growth and progression have been introduced into clinical practice for advanced (locally advanced or metastatic) BCC. We performed a comprehensive literature review on metastatic BCC and found at least 915 cases reported to date. In addition, we extensively discussed the differential diagnosis of metastatic BCC, and outlined the advances in clinical therapeutics involving these small molecules.

Metastatic Cutaneous Basal Cell Carcinoma: Report of 2 Cases Preceding the Hedgehog Pathway Antagonists Era

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. However, metastatic BCC is a very rare event with weakly effective therapeutic options and a poor prognosis, until a few years ago. In 2012, small-molecule therapies, capable of inactivating the hedgehog signaling pathway and thus reducing tumor growth and progression, were introduced into clinical practice for the treatment of patients with advanced BCC. We present retrospectively 2 personal cases of metastatic BCC of the skin, from the premolecular therapy era, from primary tumors that arose years before in the head and neck area. The former case occurred in a 45-year-old woman with a history of recurrent BCC of the retroauricular skin who eventually died due to diffuse metastatic spread. The latter case concerned a 70-year-old man also with a history of recurrent BCC of the nasal-perinasal skin who developed multiple subcutaneous and lymph node metastases in the neck. In both cases, the diagnoses were based on biopsies of the metastatic sites. The first patient died 5 months after the diagnosis of metastatic disease, while the second was alive and disease-free 2 years after neck lymph node dissection and external radiation therapy, and then lost to follow-up. We extensively discuss several tumor entities with basal or basaloid features that may enter the differential diagnosis with BCC in metastatic sites. In addition, we briefly summarize the advances in clinical therapeutics using small molecules, which are now an integral part of the treatment of such advanced BCC cases.

BCRP expression in schwannoma, plexiform neurofibroma and MPNST

Background

peripheral nerve sheath tumors comprise a broad spectrum of neoplasms. Vestibular schwannomas and plexiform neurofibromas are symptomatic albeit benign, but a subset of the latter pre-malignant lesions will transform to malignant peripheral nerve sheath tumors (MPNST). Surgery and radiotherapy are the primary strategies to treat these tumors. Intrinsic resistance to drug therapy characterizes all three tumor subtypes. The breast cancer resistance protein BCRP is a transmembrane efflux transporter considered to play a key role in various biological barriers such as the blood brain barrier. At the same time it is associated with drug resistance in various tumors. Its potential role in drug resistant tumors of the peripheral nervous system is largely unknown.

Objective

to assess if BCRP is expressed in vestibular schwannomas, plexiform neurofibromas and MPNST.

Material and methods

immunohistochemical staining for BCRP was performed on a tissue microarray composed out of 22 vestibular schwannomas, 10 plexiform neurofibromas and 18 MPNSTs.

Results

sixteen out of twenty-two vestibular schwannomas (73%), nine out of ten plexiform neurofibromas (90%) and six out of eighteen MPNST (33%) expressed BCRP in the vasculature. Tumor cells were negative.

Conclusion

BCRP is present in the vasculature of vestibular schwannomas, plexiform neurofibromas and MPSNT. Therefore, it may reduce the drug exposure of underlying tumor tissues and potentially cause failure of drug therapy.

A Case of Metastatic Adamantinoma That Responded Well to Sunitinib

Adamantinoma is a rare low-grade malignant bone tumor of epithelial origin. Metastatic adamantinoma has been reported to be resistant to chemotherapy. We report a case of metastatic adamantinoma to the lung, 10 years after the initial diagnosis of tibial mass. The patient received radiation therapy to the lung with partial response. A surveillance PET scan revealed progression of the lung mass and biopsy confirmed to be progressive residual metastatic adamantinoma. He received carboplatin and etoposide for 7 months and achieved a partial response. Four months later, PET scan showed disease progression. We started him on sunitinib, a multikinase inhibitor. He achieved a good partial response for 3 years. He died due to pneumonia at the age of 72.

Role of Vascular Endothelial Growth Factor a in Children with Acquired Airway Stenosis

Objectives:

Vascular endothelial growth factor A (VEGF-A) is important in the angiogenic response for wound healing. This study investigated whether VEGF-A may play a role in the pathogenesis of acquired airway stenosis.

Methods:

Eight lesions from 5 pediatric patients with subglottic stenosis after airway reconstruction (N = 4) or prolonged intubation (N = 1) and normal laryngeal tissue from 5 autopsy patients were included. Formalin-fixed sections of subglottic tissue from each patient were examined by in situ hybridization for the presence of messenger RNA (mRNA) for VEGF-A, vascular endothelial growth factor receptor 1 (VEGFR-1), and vascular endothelial growth factor receptor 2 (VEGFR-2).

Results:

Strong expression of VEGF-A mRNA was noted in hyperplastic squamous epithelium overlying granulation tissue. Strong expression of VEGFR-1 and VEGFR-2 was noted in the endothelial cells within granulation tissue. No strong labeling of VEGF-A mRNA or its receptors was noted in 2 specimens with mature scar tissue or in the control specimens.

Conclusions:

The angiogenic growth factor VEGF-A is strongly expressed in hyperplastic epithelium overlying granulation tissue in airway stenosis. Also, VEGFR-1 and VEGFR-2 mRNAs are strongly expressed in the endothelial cells of granulation tissue. This finding suggests an important role of VEGF-A in the pathogenesis of airway scar formation and stenosis.

Role of Vascular Endothelial Growth Factor–A in Recurrent Respiratory Papillomatosis

Vascular endothelial growth factor–A (VEGF-A) is known to play an important role in the angiogenic response essential for tumor growth in a variety of human and experimental tumors. This study was designed to investigate whether VEGF-A may play a role in the pathogenesis of recurrent respiratory papillomatosis (RRP). A retrospective study with institutional review board approval was performed at a tertiary care medical center on 12 patients with a history of laryngeal RRP. Their ages at the time of initial diagnosis ranged from 19 to 96 months (mean, 56 months). All patients had involvement of right and left true vocal cords. All patients required multiple endoscopic procedures (range, 4 to 66; mean, 12). Normal pediatric larynx samples from 5 autopsy patients were used as controls. Formalin-fixed, paraffin-embedded sections of laryngeal squamous papillomas from the 12 patients with a diagnosis of RRP and the 5 control patients were examined by in situ hybridization for the presence of messenger RNA (mRNA) for VEGF-A and vascular endothelial growth factor receptor 1 (VEGFR-1) and vascular endothelial growth factor receptor 2 (VEGFR-2). The biopsy specimens were from the true vocal cord (N = 10) or subglottis (N = 2) in the patients with RRP and consisted of large sections of larynx including the true vocal cord in the control patients (N = 5). Strong expression of VEGF-A mRNA was noted in the squamous epithelium of papillomas of all 12 patients. Strong expression of VEGFR-1 and VEGFR-2 was noted in the endothelial cells of the underlying vessels in all 12 patients. Neither strong labeling of VEGF-A mRNA nor labeling of its receptors was noted in the control patients. We conclude that the angiogenic growth factor VEGF-A is strongly expressed in the epithelium of squamous papillomas in RRP. Also, VEGFR-1 and VEGFR-2 mRNAs are strongly expressed by underlying vascular endothelial cells, suggesting an important role in the pathogenesis of RRP.

Intratumoral hemorrhage, vessel density, and the inflammatory reaction contribute to volume increase of sporadic vestibular schwannomas

Vestibular schwannomas show a large variation in growth rate, making prediction and anticipation of tumor growth difficult. More accurate prediction of clinical behavior requires better understanding of tumor biological factors influencing tumor progression. Biological processes like intratumoral hemorrhage, cell proliferation, microvessel density, and inflammation were analyzed in order to determine their role in vestibular schwannoma development. Tumor specimens of 67 patients surgically treated for a histologically proven unilateral vestibular schwannoma were studied. Preoperative magnetic resonance imaging (MRI) scans were used to determine tumor size and to classify tumors as homogeneous, inhomogeneous, and cystic. Immunohistochemical studies evaluated cell proliferation (histone H3 and Ki-67), microvessel density (CD31), and inflammation (CD45 and CD68). Intratumoral hemorrhage was assessed by hemosiderin deposition. The expression patterns of these markers were compared with tumor size, tumor growth index, MRI appearance, patients’ age, and duration of symptoms. No relation between cell proliferation and clinical signs of tumor volume increase or MRI appearance was found. Intratumoral hemosiderin, microvessel density, and inflammation were significantly positively correlated with tumor size and the tumor growth index. Cystic and inhomogeneous tumors showed significantly more hemosiderin deposition than homogeneous tumors. The microvessel density was significantly higher in tumors with a high number of CD68-positive cells. The volume increase of vestibular schwannomas is not based on cell proliferation alone. Factors like intratumoral bleeding, (neo)vascularization, and intensity of the inflammatory reaction also influence tumor volume.

Restoration of chemosensitivity for doxorubicin and cisplatin in chondrosarcoma in vitro: BCL-2 family members cause chemoresistance

BACKGROUND

Chondrosarcomas are malignant cartilage-forming tumors notorious for their resistance to conventional chemo- and radiotherapy. Postulated explanations describe the inaccessibility due to abundant hyaline cartilaginous matrix, presence of multidrug resistance (MDR) pumps, and expression of anti-apoptotic BCL-2 family members.

MATERIALS AND METHODS

We studied the sensitivity of chondrosarcoma cell lines (SW1353, CH2879, JJ012, OUMS27) and two primary cultures for doxorubicin and cisplatin. We examined the role of extracellular matrix using three-dimensional (3D) pellet models and MDR pump activity using fluorescence-activated cell sorter analysis. The role of BCL-2 family members was investigated using the BH3 mimetic ABT-737.

RESULTS

Chondrosarcoma cells showed highest resistance to cisplatin. 3D cell pellets, morphologically strongly resembling chondrosarcoma in vivo, confirmed nuclear incorporation of doxorubicin. MDR pump activity was heterogeneous among cultures. Chondrosarcoma cells responded to ABT-737 and combination with doxorubicin led to complete loss of cell viability and apoptosis with cytochrome C release.

CONCLUSIONS

Despite MDR pump activity and abundance of hyaline cartilaginous matrix, doxorubicin is able to accumulate in the cell nuclei. By repairing the apoptotic machinery, we were able to sensitize chondrosarcoma cells to doxorubicin and cisplatin, indicating an important role for BCL-2 family members in chemoresistance and a promising new treatment strategy for inoperable chondrosarcoma.

Dedifferentiated adamantinoma associated with fibrous dysplasia

A 21-year-old patient presented with an aggressive lesion of the left tibia associated to lymph nodes and lung metastasis. Histological examination revealed a high grade spindle cell sarcoma involving some areas of cytokeratine positive cells. Ultrastructural examination showed the presence of epithelial features in the sarcomatoid cells. The diagnosis of dedifferentiated spindle-celled adamantinoma was established. A second lesion of the right tibia was diagnosed as fibrous dysplasia. The patient had a leg amputation. He died 2 years later with multiple lung and bone metastases. The diagnosis of dedifferentiated adamantinoma should be considered when a clinician is confronted with a tibial biopsy of a "keratin-positive sarcoma". The association with fibrous dysplasia in this case is discussed.

Adamantinoma with plasmacytoid features: expanding the spectrum of a diagnostically challenging entity

Adamantinoma is a rare neoplasm that characteristically involves the tibia. In many instances, typical location within the tibia, very slow course, and a typical radiographic appearance can strongly suggest the correct diagnosis. We present a case that has both unusual radiographic findings and uncharacteristic histology. In this case, radiologic imaging showed a poorly defined lytic lesion within the distal, lateral tibia extending to the joint with central necrosis, overlying periosteal reaction and possible tumor spread into soft tissue. The histology of this lesion showed pronounced vascularity and surrounding large neoplastic cells with plasmacytoid morphology. The combination of these features led to an initial misdiagnosis as metastatic carcinoma from unknown primary.

Osteofibrous dysplasia and adamantinoma

Osteofibrous dysplasia (OFD) is a rare, benign, fibro-osseous lesion that typically is seen within the cortex of the tibia in children. Adamantinoma (AD) is a rare, low-grade malignant primary bone tumor that occurs most often in the tibia and/or fibula of adolescent persons and young adults; however, it has been reported in other long bones, as well. Immunohistochemical and ultrastructural evidence has shown that the neoplastic cell in AD derives from an epithelial lineage. More recently, published reports have described another clinical entity-differentiated or OFD-like AD-that appears to lie between OFD and AD along a spectrum of disease. Controversy exists as to whether OFD is a precursor lesion to AD or whether OFD may be a residual lesion resulting from a spontaneously regressing AD. Management of OFD varies from observation to surgical intervention, depending on the age of the patient and the extent of the lesion. Management of AD requires surgical resection with wide margins, followed by appropriate reconstruction, to minimize the risk of local recurrence or metastasis.

Adamantinoma of the tibia treated with a new intramedullary diaphyseal segmental defect implant

In this case report, a 75-year old male presented with a mass on the anterior surface of the mid-shaft of the right tibia. Imaging studies showed a well-circumscribed radiolucent lesion in the anterior tibial cortex, without soft tissue extension. Plain radiographs and computed tomography scan of the chest were negative. Histological diagnosis was consistent with adamantinoma, a rare primary bone tumour. Wide tumour resection of approximately 16 cm of the tibial diaphysis with a surrounding cuff of normal tissue was performed. The bone defect was reconstructed using an intramedullary diaphyseal segmental defect fixation system. At 26 months post-operatively the patient is alive with no evidence of local recurrence, distant metastases or implant failure. The intramedullary diaphyseal segmental defect fixation system is associated with excellent oncological and functional outcomes. Intra-operative modularity, ease of application, immediate post-operative stability and rapid rehabilitation are the major advantages of this diaphyseal prosthesis.

Reduced human leukocyte antigen expression in advanced-stage Ewing sarcoma: implications for immune recognition

Ewing sarcoma (EWS) is a tumour most commonly arising in bone, although on occasion in soft tissue, with a poor prognosis in patients with refractory or relapsed disease, despite multimodal therapy. Immunotherapeutic strategies based on tumour-reactive T and/or natural killer cells may improve the treatment of advanced-stage EWS. Since cellular immune recognition critically depends on human leukocyte antigen (HLA) expression, knowledge about HLA expression in EWS is crucial in the design of cellular immunotherapeutic strategies. Constitutive and IFNgamma-induced HLA class I expression was analysed in EWS cell lines (n = 6) by flow cytometry, using antibodies against both monomorphic and allele-specific antigens. Expression of antigen processing pathway components and beta-2 microglobulin (beta2m) was assessed by western blot. Expression of class II transactivator (CIITA), and its contribution to HLA class II expression, was evaluated by qRT-PCR, transduction assays, and flow cytometry. beta2m/HLA class I and class II expression was validated in EWS tumours (n = 67) by immunofluorescence. Complete or partial absence of HLA class I expression was observed in 79% of EWS tumours. Lung metastases consistently lacked HLA class I and sequential tumours demonstrated a tendency towards decreased expression upon disease progression. Together with absent or low constitutive expression levels of specific HLA class I loci and alleles, and differential induction of identical alleles by IFNgamma in different cell lines, these results may reflect the existence of an immune escape mechanism. Inducible expression of TAP-1/-2, tapasin, LMP-2/-7, and the beta2m/HLA class I complex by IFNgamma suggests that regulatory mechanisms are mainly responsible for heterogeneity in constitutive class I expression. EWSs lack IFNgamma-inducible HLA class II, due to lack of functional CIITA. The majority of EWS tumours, particularly if advanced-stage, exhibit complete or partial absence of both classes of HLA. This knowledge will be instrumental in the design of cellular immunotherapeutic strategies for advanced-stage EWS.

Adamantinoma: a clinicopathological review and update

Adamantinoma is a primary low-grade, malignant bone tumor that is predominantly located in the mid-portion of the tibia. The etiology of the tumor is still a matter of debate. The initial symptoms of adamantinoma are often indolent and nonspecific and depend on location and extent of the disease. Histologically, classic adamantinoma is a biphasic tumor characterized by epithelial and osteofibrous components that may be intermingled with each other in various proportions and differentiating patterns. To assure the histological diagnosis, pathologists should employ immunohistochemistry for demonstrating the sometimes sparse epithelial cell nests when the radiological features are suggestive of adamantinoma. There is paucity of compiled data over adamantinoma in the literature, hence authors tried to make a comprehensive review which must be of use to beginners and trained pathologists. Our objective is to further define the clinicoradiologic features and pathologic spectra of adamantinoma.

Decreased EXT expression and intracellular accumulation of heparan sulphate proteoglycan in osteochondromas and peripheral chondrosarcomas

Mutational inactivation of EXT1 or EXT2 is the cause of hereditary multiple osteochondromas. These genes function in heparan sulphate proteoglycan (HSPG) biosynthesis in the Golgi apparatus. Loss of heterozygosity of the EXT1 locus at 8q24 is frequently found in solitary osteochondromas, whereas somatic mutations are rarely found. We investigated the expression of EXT1 and EXT2 (quantitative RT-PCR) and of different HSPGs (immunohistochemistry) in solitary and hereditary osteochondromas and in cases with malignant progression to secondary peripheral chondrosarcoma, in relation to possible mutations and promoter methylation. The mutation status of patients with multiple osteochondromas correlated with decreased EXT1 or EXT2 expression found in their resected tumours. We could not show somatic point mutations or promoter hypermethylation in 17 solitary tumours; however, EXT1 expression was decreased in 15 cases, whereas EXT2 was not. Intracellular accumulation of syndecan-2 and heparan sulphate-bearing isoforms of CD44 (CD44v3) was found in most tumours, which concentrated in the Golgi apparatus as shown by confocal microscopy. This contrasted with the extracellular expression found in normal growth plates. In conclusion, mutational inactivation of either EXT1 or EXT2 leads to loss of mRNA expression of the corresponding gene. We hypothesize that loss of EXT expression disrupts the function of the EXT1/2 complex in HSPG biosynthesis, resulting in the intracellular accumulation of HSPG core proteins that we found in these tumours.

Epithelioid and Epithelial Neoplasms of Bone

Context.—Epithelioid and epithelial neoplasms seen in bone are rare and include epithelioid variants of vascular lesions, osteoblastoma, osteosarcoma, chordoma, and chondroblastoma as well as adamantinoma and metastatic carcinoma.

Objective.—To provide an overview of tumors with epithelioid histology and address the clinical context and diagnostic issues.

Data Sources.—Pertinent literature is reviewed with emphasis on recent and controversial issues.

Conclusions.—The differential diagnosis in epithelioid/ epithelial lesions of bone is limited. The primary consideration in many cases is distinguishing primary from metastatic lesions.

Expression of Cellular FLICE Inhibitory Protein, Caspase-8, and Protease Inhibitor-9 in Ewing Sarcoma and Implications for Susceptibility to Cytotoxic Pathways

PURPOSE

Ewing sarcoma is a common pediatric bone tumor with an unfavorable prognosis for metastatic or recurrent disease. Cellular immunotherapy may provide new treatment options and depends on the cytolytic death receptor and perforin/granzyme pathways. Expression of death receptor pathway inhibitor cellular FLICE inhibitory protein (cFLIP), initiator caspase-8, and granzyme B inhibitor protease inhibitor-9 (PI-9) have been reported to determine susceptibility to cell- and chemotherapy-mediated killing in several tumor types. Here, we have studied their in vitro and in vivo expression in Ewing sarcoma and the implications for susceptibility to cytotoxicity.

EXPERIMENTAL DESIGN

Ewing sarcoma cell lines (n = 8) were tested for cFLIP, PI-9, and caspase-8 expression. Functional significance was tested by anti-Fas antibody (death receptor pathway) or natural killer cell (perforin/granzyme pathway) treatment. Immunohistochemistry was done on 28 sections from 18 patients. In half of the cases, sequential material, including metastases, was available.

RESULTS

Although all tested Ewing sarcoma cell lines expressed cFLIP, resistance to CD95/Fas-mediated apoptosis was only observed in two cell lines lacking caspase-8 expression. PI-9 was expressed at low levels in four of eight Ewing sarcoma cell lines, but positive cell lines remained susceptible to perforin/granzyme-mediated killing. In primary Ewing sarcoma, including metastases, cFLIP was abundantly expressed in 18 of 18 patients. Caspase-8 was expressed in all patients but showed more intertumoral and intratumoral variation in both intensity and heterogeneity of staining. PI-9, in contrast, was undetectable.

CONCLUSIONS

The expression patterns of cFLIP, caspase-8, and the absence of PI-9 provide a rationale to preferentially exploit the perforin/granzyme pathway in cytotoxic therapies against Ewing sarcoma.

EXT-related pathways are not involved in the pathogenesis of dysplasia epiphysealis hemimelica and metachondromatosis

Dysplasia epiphysealis hemimelica (DEH) and metachondromatosis (MC) are considered in the differential diagnosis of solitary and hereditary osteochondromas. Both are rare disorders with DEH demonstrating cartilaginous overgrowth of an epiphysis and MC exhibiting synchronous enchondromas and osteochondromas. Ten cases of DEH and two of MC were compared with osteochondromas at the histological and molecular level. Histologically, clumping of chondrocytes within a fibrillary chondroid matrix is characteristic of DEH, while osteochondromas and MC display the characteristic growth plate architecture. Using cDNA microarray analysis we demonstrate that DEH and MC cluster separately from osteochondromas and growth plates. The EXT genes, involved in the hereditary multiple osteochondromas syndrome, and downregulated in osteochondroma, were normally expressed in DEH and MC as shown by quantitative reverse transcriptase-polymerase chain reaction (qPCR). EXT is involved in heparan sulphate biosynthesis, important for Indian Hedgehog/ParaThyroid Hormone Like Hormone (IHH/PTHLH) growth plate signalling pathways. IHH/PTHLH signalling molecules were expressed in DEH and MC as shown by both qPCR and immunohistochemistry, suggesting that this pathway is active. This is in contrast to osteochondroma, in which PTHLH signalling is downregulated. Thus, lesions of DEH and MC are separate entities from osteochondroma as confirmed by their different cDNA and protein expression profiles. Downstream targets of EXT, which are downregulated in osteochondroma, are expressed in DEH and MC, suggesting that EXT signalling is not disturbed.

TGF-beta1 drives partial myofibroblastic differentiation in chondromyxoid fibroma of bone

Chondromyxoid fibroma (CMF) is a rare benign cartilaginous bone tumour with a lobular architecture containing stellate and myofibroblast-like spindle cells. The aim of this study was to investigate the presence, spatial distribution, and extent of myoid differentiation in CMF and to evaluate a possible causative role for TGF-beta1 signalling, which is known to promote smooth muscle actin (SMA) expression. Twenty cases were studied for immunoreactivity for muscle-specific actin (MSA), SMA, desmin, h-caldesmon, calponin, TGF-beta1, and plasminogen activator inhibitor type 1 (PAI-1). The extent of myofibroblastic differentiation was further investigated ultrastructurally, including immuno-electron microscopy using antibodies against MSA and SMA, focusing upon the different cell types in CMF. The expression of potential genes driving this process was quantified by Q-RT-PCR (TGF-beta1, fibronectin, its EDA splice variant, and PAI-1). Tumour cells, especially those with a spindled morphology, showed diffuse immunoreactivity for MSA, SMA, TGF-beta1, and PAI-1, while desmin, h-caldesmon, and calponin were absent. Ultrastructurally, neoplastic cells showed the presence of myofilaments and rare dense bodies, which were more prominent in spindle cells and less so in chondroblast-like cells. Immuno-electron microscopy confirmed the actin nature of these myofilaments. No fibronexus was identified. The functional activity of TGF-beta1 was demonstrated by the identification of PAI-1, a related downstream molecule both immunohistochemically as well as by Q-RT-PCR. There was a linear correlation between TGF-beta1 and PAI-1 expression. Fibronectin-EDA levels were low. We have therefore substantiated the presence of morphological, immunohistochemical, and immuno-electron microscopic partial myofibroblastic differentiation in CMF, driven by TGF-beta1 signalling.

Estrogen Signaling Is Active in Cartilaginous Tumors: Implications for Antiestrogen Therapy as Treatment Option of Metastasized or Irresectable Chondrosarcoma

PURPOSE

Chondrosarcoma is a malignant cartilaginous matrix-producing tumor that can be lethal in 10% to 50% of the patients. Surgery is the only effective treatment known as these tumors are notorious refractory to all types of conventional chemotherapy or radiotherapy. To identify a target for therapy, we want to determine whether estrogen signaling is active in chondrosarcoma because estrogen is important in the regulation of longitudinal growth that is initiated by chondrocyte proliferation and differentiation in the epiphyseal growth plate of long bones.

EXPERIMENTAL DESIGN

We studied protein expression of the estrogen receptor in 35 cartilaginous tumors as well as mRNA levels for the estrogen receptor and for aromatase, an enzyme for estrogen synthesis and another potential therapeutic target. Furthermore, the activity of aromatase was determined in vitro by the tritiated water release assay. Dose-response experiments with chondrosarcoma cultured cells were done with estrogen, androstenedione, and exemestane.

RESULTS

All chondrosarcomas tested showed mRNA and nuclear protein expression of the estrogen receptor. Also, aromatase mRNA was detected. The aromatase activity assay showed a functional aromatase enzyme in primary chondrosarcoma cultures and in a cell line. Growth of chondrosarcoma cell cultures can be stimulated by adding estrogen or androstenedione, which can be inhibited by exemestane.

CONCLUSIONS

These results show, on the RNA, protein, and cell biological levels, that the ligand and the receptor are active in estrogen-mediated signal transduction. This observation implicates potential use of targeted drugs that interfere with estrogen signaling, such as those applied for treating breast cancer.

Enchondromatosis (Ollier disease, Maffucci syndrome) is not caused by the PTHR1 mutation p.R150C

Enchondromatosis (Ollier disease, Maffucci syndrome) is a rare developmental disorder characterized by multiple enchondromas. Not much is known about its molecular genetic background. Recently, an activating mutation in the parathyroid hormone receptor type 1 (PTHR1) gene, c.448C>T (p.R150C), was reported in two of six patients with enchondromatosis. The mutation is thought to result in upregulation of the IHH/PTHrP pathway. This is in contrast to previous studies, showing downregulation of this pathway in other cartilaginous tumors. Therefore, we investigated PTHR1 in enchondromas and chondrosarcomas from 31 enchondromatosis patients from three different European countries, thereby excluding a population bias. PTHR1 protein expression was studied using immunohistochemistry, revealing normal expression. The presence of the described PTHR1 mutation was analyzed, using allele-specific oligonucleotide hybridization confirmed by sequence analysis, in tumors from 26 patients. In addition, 11 patients were screened for other mutations in the PTHR1 gene by sequence analysis. Using both allele-specific oligonucleotide hybridization and sequencing, we could neither confirm the previously found mutation nor find any other mutations in the PTHR1 gene. These results indicate that the PTHR1 gene is not, in contrast to previous suggestions, the culprit for enchondromatosis.

The use of Bcl-2 and PTHLH immunohistochemistry in the diagnosis of peripheral chondrosarcoma in a clinicopathological setting

Distinguishing osteochondroma from low-grade secondary peripheral chondrosarcoma can be difficult. In osteochondroma, growth-signalling pathways are thought to be downregulated through exostosin (EXT) inactivation. A previous pilot study focusing on expression of putative EXT downstream effectors indicated that progression of osteochondroma towards grade I chondrosarcoma was characterised by upregulation of Bcl-2 and parathyroid hormone-like hormone (PTHLH). We investigated their use as diagnostic markers in a large nationwide series of 71 osteochondromas and 34 chondrosarcomas. Bcl-2 immunohistochemistry proved to be a valuable diagnostic tool: scoring negative in 95% (specificity) of the osteochondromas and positive in 57% (sensitivity) of the chondrosarcomas, reaching a positive predictive value of 84% and negative predictive value of 82%. Positivity was not related to age, hereditary status, gender or thickness of the cartilage cap. Presence of internal controls and verification using mRNA in situ hybridisation strengthened the reliability of the immunohistochemical staining. PTHLH showed more variable staining, being positive in osteochondromas from females or adolescent males, suggesting age- and gender-dependent expression. Thus, in cases where the distinction between osteochondroma and chondrosarcoma is difficult, Bcl-2 is a valuable diagnostic marker for malignancy, regardless of tumour size, patient gender or age, and this can be extended with PTHLH for non-adolescent male patients.

A distinct phenotype characterizes tumors from a putative genetic trait involving chondrosarcoma and breast cancer occurring in the same patient

Recently, we documented an increased risk for the occurrence of breast- and cartilaginous tumors in the same patient, statistically pointing towards a potential genetic trait. This trait is most probably not associated with mutations in the two major hereditary breast cancer genes since no cases of enchondroma or chondrosarcoma were found in Dutch BRCA1 and BRCA2 families. We were able to collect and review the tumor tissue samples from 34 patients with both breast- and cartilaginous tumors and compared histopathological and immunohistochemical features of these tumors with controls. Breast cancer controls were available from literature data generated to compare familial breast cancers with nonselected cases. Clinical markers for chondrosarcoma controls were collected from the Netherlands Committee of Bone Tumors. Immunohistochemical data on chondro-tumor controls were available from our own files. Breast tumors of patients with cartilaginous sarcomas showed a significantly higher mitotic count (P=0.001), contained less lymphocyte infiltrate (P=0.025) and less nuclear pleomorphism. Remarkably, all cartilaginous tumors are of one common histological category originating centrally (P=0.014). Estrogen receptor and p53 expression were significantly higher (P<0.001) in breast cancer associated with chondro-tumors. p21 staining was more often negative in chondro-tumors associated with breast cancer. In seven cases of breast cancer, we found a slight decrease in CHEK2 expression. However, we could not identify the CHEK2 1100delC mutation in these cases nor in cases with normal CHEK2 expression. Hierarchical cluster analysis of all parameters within chondro-tumor-associated breast cancer specimens revealed two different subgroups, the largest one associated with estrogen receptor-positive breast cancer, which may distinguish sporadic cases from those belonging to the potential genetic trait. These distinct phenotypic findings support the existence of a new hitherto unrecognized syndrome, characterized by an increased risk to develop both breast cancer and centrally originating cartilaginous tumors.

Dedifferentiated adamantinoma with revertant mesenchymal phenotype

In adamantinoma of long bones, an osteofibrous dysplasia-like form with scattered epithelial elements and a classic form with abundant epithelium are distinguished. Osteofibrous dysplasia-like adamantinomas occur in children and adolescents and behave relatively benign, whereas classic adamantinomas predominate in adults and have a more aggressive clinical course. Because some osteofibrous dysplasia-like tumors have progressed to classic adamantinomas, it is hypothesized that the former is a potential precursor of the latter, showing mesenchymal-to-epithelial transformation. We report a new morphologic variant of adamantinoma in three patients with sarcomatoid transformation of the epithelial component: one in a primary tumor and two in local recurrences. One patient died of metastatic disease. Histologically, the tumors showed loss of the original characteristic epithelial differentiation with transition to fields of highly pleomorphic cells without epithelial features, high mitotic count, and deposition of osteoid and chondroid matrix. These dedifferentiated areas showed pankeratin positivity as well, although there were some changes in keratin subclass profile compared with other classic adamantinomas. This peculiar variant of long bone adamantinoma shows that in addition to mesenchymal-to-epithelial transformation in the early stage of development, progression to an aggressive subtype may be associated with epithelial-to-mesenchymal transition ("sarcomatoid dedifferentiation"), in which the epithelial immunophenotype is conserved. Thereby it may serve as an example of the plasticity of the mesenchymal phenotype. When confronted with a biopsy of a cortical tumor of the tibia showing sarcomatoid morphology and keratin positivity, adamantinoma should be included in the differential diagnosis, as its distinction has important implications for treatment and prognosis.

Adamantinoma, osteofibrous dysplasia and differentiated adamantinoma

For just over 100 years, adamantinoma has been recognized as a primary bone tumor with epithelial characteristics and predominantly involving the tibia. Osteofibrous dysplasia is a fibro-osseous lesion also predominantly confined to the tibia with radiologic features similar to those of adamantinoma. This lesion has been shown by immunohistochemical studies to frequently contain cytokeratin-positive epithelial cells. More recently, a third group of cases with clinical and radiologic features similar to those of osteofibrous dysplasia have demonstrated more overt strands of epithelial cells within a fibro-osseous background and have been categorized as "differentiated", "regressive", "juvenile intracortical" or "osteofibrous dysplasia-like" adamantinoma. Cytokeratin subset immunohistochemical stains and cytogenetic studies performed in recent years suggest a common histogenesis for these three entities. This article reviews the clinical, radiologic and pathologic features of these entities as well as their prognostic significance. It also reviews the results of the immunohistochemical and cytogenetic studies which establish a common histogenetic relationship.

Up-regulation of PTHrP and Bcl-2 expression characterizes the progression of osteochondroma towards peripheral chondrosarcoma and is a late event in central chondrosarcoma

Chondrosarcomas are malignant cartilage-forming tumors arising centrally in bone (central chondrosarcoma) or within the cartilaginous cap of osteochondroma (peripheral chondrosarcoma). For hereditary multiple osteochondromas, two responsible genes, EXT1 and EXT2, have been cloned. Their recently elucidated role in heparan sulfate biosynthesis and Hedgehog diffusion leads to the hypothesis that EXT inactivation affects fibroblast growth factor (FGF) and Indian Hedgehog (IHh)/parathyroid hormone-related peptide (PTHrP) signaling, two important pathways in chondrocyte proliferation and differentiation. The expression of PTHrP, PTHrP-receptor, Bcl-2, FGF2, FGFR1, FGFR3, and p21 is investigated by immunohistochemistry in osteochondromas (n = 24) and peripheral (n = 29) and central (n = 20) chondrosarcomas. IHh/PTHrP and FGF signaling molecules are mostly absent in osteochondromas. Although no somatic EXT mutations were found in sporadic osteochondromas, the putative EXT downstream targets are affected similarly in sporadic and hereditary tumors. In chondrosarcomas, re-expression of FGF2, FGFR1, PTHrP, Bcl-2, and p21 is found. Expression levels increase with increasing histological grade. Up-regulation of PTHrP and Bcl-2 characterizes malignant transformation of osteochondroma because PTHrP and Bcl-2 expression is significantly higher in borderline and grade I peripheral chondrosarcomas compared with osteochondromas. In contrast, up-regulation of PTHrP and Bcl-2 seems to be a late event in central cartilaginous tumorigenesis because expression is mainly restricted to high-grade central tumors.

Expression of cytokeratin 1, 5, 14, 19 and transforming growth factors-beta1, beta2, beta3 in osteofibrous dysplasia and adamantinoma: A possible association of transforming growth factor-beta with basal cell phenotype promotion

To elucidate the precise origin and characteristics of the epithelial components of osteofibrous dysplasia (OF) and adamantinoma (AD), the expression of transforming growth factor (TGF)-beta1, beta2 and beta3 and cytokeratin (CK) subtypes were studied in five cases of AD and 18 cases of OF by immunohistochemistry. CK1 was expressed in 10 out of 18 OF cases; CK5 was expressed in one OF case; CK14 was positively stained in 10 cases of OF; CK19 was positively stained in 16 OF cases; CK1 was expressed in three out of five AD cases; CK5 was expressed in one case of AD; CK14 was positively stained in four AD cases; and CK19 was positively stained in five AD cases. In OF, TGF-beta1, beta2 and beta3 were expressed in both fibroblasts and osteoblasts. In AD, TGF-beta1, beta2 and beta3 were expressed in both epithelial and fibrous components. These results suggest that epithelial components of AD and OF share epidermal characteristics, CK1, express basal cell phenotype and cytokeratins 5, 14 and 19. In addition to these epithelial characteristics, strong immunoreactivity for TGF-beta poses the possibility of TGF-beta promotion of basal cell phenotype expression for the epithelial components in OF and AD.

Molecular genetic characterization of both components of a dedifferentiated chondrosarcoma, with implications for its histogenesis

Dedifferentiated chondrosarcoma is defined as a high-grade, anaplastic sarcoma adjacent to a low-grade malignant cartilage-forming tumour. Controversy remains as to whether the anaplastic and cartilaginous components are derived from a common precursor cell, or whether they represent separate genotypic lineages (collision tumour). Both components of a case of dedifferentiated chondrosarcoma were therefore separately investigated by loss of heterozygosity (LOH) analysis, comparative genomic hybridization (CGH), DNA flow cytometry, and p53 analysis. Both showed p53 overexpression and an identical somatic 6 bp deletion in exon 7 of p53. Combination of the CGH and LOH results revealed that both components had lost the same copy of chromosome 13. These results provide compelling evidence in this case for a common origin, instead of the 'collision tumour' theory. Certain genotypic alterations were not shared. The anaplastic component showed severe aneuploidy, LOH at additional loci, and amplification and deletion of several chromosome parts. In contrast, the cartilaginous component had lost chromosomes 5, 22, 17p and part of 16p and revealed an amplification of 17q. The LOH and CGH results further demonstrated that the two components had lost a different copy of chromosome 4. Thus, a substantial number of genetic alterations have occurred after the diversion of the two components, indicating that the separation of the two clones, derived from a single precursor, was a relatively early event in the histogenesis of this case of dedifferentiated chondrosarcoma.

Chondrosarcoma of the phalanx: a locally aggressive lesion with minimal metastatic potential: a report of 35 cases and a review of the literature

BACKGROUND

Enchondroma is the most common primary benign bone tumor of the hand, especially the phalanges, whereas chondrosarcoma is uncommon at this site. Although phalangeal chondrosarcoma may have ominous histologic features, its biologic behavior is relatively indolent.

METHODS

Thirty-five cases of phalangeal lesions previously diagnosed as chondrosarcoma were studied. Histologic and tumor-biologic parameters (Ki-67 and p53 immunohistochemistry) were investigated and correlated with clinical behavior.

RESULTS

All cases were characterized by unequivocal malignant histologic features (Grade 2 or higher) or Grade 1 malignant histologic features combined with the presence of cortical destruction and soft tissue extension. The median age of the patients at the time of diagnosis was 67 years (range 21-87 years), with a slight female predominance. Occurrence in the hand was more common than in the foot, with the proximal phalanx affected most often. Treatment varied from local therapy (curettage or local excision) in 16 patients to amputation or exarticulation in 19 cases. Follow-up ranged from 8-432 months for 28 patients. Ten of 15 tumors treated by local therapy recurred whereas none of 13 tumors treated by radical surgery recurred. The median survival was 20.8 years; none of 28 patients developed metastases nor died of disease. Both the type of treatment and localization in the proximal phalanx were associated independently with local recurrence.

CONCLUSIONS

Phalangeal chondrosarcoma behaves as a locally aggressive lesion and, in contrast to chondrosarcomas located elsewhere, rarely metastasizes. Treatment is indicated only because of its locally destructive growth. The authors believe that given the excellent survival data, curettage with adequate follow-up should be considered as the treatment of choice if technically feasible, especially in those cases in which amputation would lead to a significant loss of hand function.

Synovial sarcoma specific translocation associated with both epithelial and spindle cell components

The biphasic subtype of synovial sarcoma consists of both epithelial and spindle cell components. To address the relationship between the different cellular components found in synovial sarcoma, we deduced the presence of the synovial sarcoma-specific der(X)t(X;18)(p11.2;q11.2), and involvement of the SSX1 gene in both the epithelial/glandular and spindle cell components of 3 biphasic synovial sarcomas with wide ranging proportions of each of the 2 elements. This has been achieved using a 2-color fluorescence in situ hybridization (FISH) methodology that we had developed recently for analysis paraffin-embedded material. The presence of the rearrangement could be deduced in histologically defined regions and the results showed clearly that the rearrangement was present in both cellular components. This finding provides direct genetic evidence for biphasic synovial sarcomas being clonal and truly biphasic.