Chondromyxoid fibroma resemblesin vitro chondrogenesis, but differs in expression of signalling molecules

Differential Diagnosis of Cartilaginous Lesions of Bone

CONTEXT.—

Cartilaginous tumors represent one of the most common tumors of bone. Management of these tumors includes observation, curettage, and surgical excision or resection, depending on their locations and whether they are benign or malignant. They can be diagnostically challenging, particularly in small biopsies. In rare cases, benign tumors may undergo malignant transformation.

OBJECTIVE.—

To review common cartilaginous tumors, including in patients with multiple hereditary exostosis, Ollier disease, and Maffucci syndrome, and to discuss problems in the interpretation of well-differentiated cartilaginous neoplasms of bone. Additionally, the concept of atypical cartilaginous tumor/chondrosarcoma grade 1 will be discussed and its use clarified.

DATA SOURCES.—

PubMed (US National Library of Medicine, Bethesda, Maryland) literature review, case review of archival cases at the Massachusetts General Hospital, and personal experience of the authors.

CONCLUSIONS.—

This review has examined primary well-differentiated cartilaginous lesions of bone, including their differential diagnosis and approach to management. Because of the frequent overlap in histologic features, particularly between low-grade chondrosarcoma and enchondroma, evaluation of well-differentiated cartilaginous lesions should be undertaken in conjunction with thorough review of the imaging studies.

Preliminary Exploration of the Diagnosis and Treatment of Skull-Based Chondromyxoid Fibromas

BACKGROUND

Chondromyxoid fibromas (CMFs) are benign tumors that occur rarely in the skull base.

OBJECTIVE

To conduct a preliminary exploration of the diagnosis and treatment of cranial CMFs.

METHODS

A retrospective analysis of 19 cases of CMFs in the base of the skull between 2009 and 2014 in our hospital was conducted. The clinical manifestations, imaging characteristics, pathology, treatment strategies, and outcomes were examined.

RESULTS

The study cohort included 7 women (36.8%) and 12 men (63.2%), and symptom duration ranged from 1 mo to 5 yr. Of the 19 intracranial CMF cases examined, 15 (78.9%) conformed with the diagnostic criteria for extracranial CMF. Resection operations yielded subtotal removal of 13 tumors (68.4%) and partial removal of 6 tumors (31.6%). Postoperative pathological analysis demonstrated that the tumors were characterized by spindle-shaped or stellate cells arranged in a myxoid matrix without mitoses or permeation. Follow-up (range 2-7.3 yr; mean, 4.4 ± 1.7 yr) revealed that symptoms improved postoperatively in 15 cases (78.9%), were maintained in 2 cases (10.5%), and worsened in 2 cases (10.5%). Imaging follow-up revealed that residual tumors were stable in 18 cases (94.7%) and enlarged in 1 case (5.3%).

CONCLUSION

An accurate diagnosis should involve comprehensive consideration of clinical, radiological, and pathological features. The treatment strategy for CMFs consists of maximizing tumor removal while protecting adjacent key structures. Postoperative stereotactic radiotherapy is appropriate for residual tumors.

Trps1 is associated with the multidrug resistance of osteosarcoma by regulating MDR1 gene expression

Multidrug resistance (MDR) is a significant clinical problem in the chemotherapy of osteosarcoma and has been linked to the cellular expression of several multidrug-efflux transporters such as MDR1/P-gp. Our inhibition of the transcription factor Trps1 led to repression of MDR1/P-gp while its overexpression resulted in upregulation of MDR1/P-gp. Flow cytometric analysis suggested Trps1 increased the release of several anti-cancer drugs, thus decreasing their accumulation. Immunohistochemical analysis of clinical samples indicated that the expression of Trps1 directly correlated with MDR1/P-gp. Trps1 inhibited TGFbeta-1 and directly bound to the MDR1 promoter. Our data demonstrate a role for Trps1 in the regulation of MDR1 expression in osteosarcoma.

Nuclear beta-catenin overexpression in metastatic sentinel lymph node is associated with synchronous liver metastasis in colorectal cancer

BACKGROUND

Beta-catenin, a component of the Wingless/Wnt signaling pathway, can activate target genes linking with the adenomatous polyposis coli (APC) gene in colorectal cancer. The purpose of this study is to investigate whether nuclear beta-catenin overexpression in metastatic sentinel lymph node(s) [SLN(s)] is associated with synchronous liver metastasis.

METHODS

Clinicopathological data from 355 patients (93 cases with liver metastasis and 262 cases without liver metastasis) were reviewed. Beta-catenin expression in metastatic SLN(s) and liver metastatic lesions was examined by immunohistochemistry. The association of nuclear beta-catenin expression in metastatic SLN(s) and liver metastatic lesions was evaluated, and the relationship between nuclear beta-catenin expression and clinicopathological characteristics was analyzed. Finally, univariate and logistic multivariate regression analyses were adopted to discriminate the risk factors of liver metastasis.

RESULTS

Nuclear beta-catenin overexpression in metastatic SLN(s) was observed in 70 patients with liver metastasis and 31 patients without liver metastasis (75.3% vs. 11.8%; P < 0.001). Nuclear beta-catenin expression was noted in all the metastatic lesions. Spearman rank correlation analysis demonstrated that nuclear beta-catenin expression in metastatic SLN(s) had a positive correlation with that in metastatic lesions (r = 0.425, P < 0.001). Univariate and multivariate analyses indicated that nuclear beta-catenin overexpression in metastatic SLN(s) correlated with liver metastasis.

CONCLUSIONS

Nuclear beta-catenin overexpression in metastatic SLN(s) is strongly associated with liver metastasis and may contribute to predict liver metastasis.

Prognostic value of nuclear β-catenin overexpression at invasive front in colorectal cancer for synchronous liver metastasis

BACKGROUND

β-catenin plays an important role in colorectal tumorigenesis. Relatively little is known about the relationship between β-catenin overexpression and liver metastasis. The purpose of this study was to investigate whether nuclear β-catenin overexpression in colorectal cancer is associated with synchronous liver metastasis.

METHODS

The β-catenin expression in tumor tissue from 486 patients with colorectal cancer was examined by immunohistochemistry. The relationship between nuclear β-catenin expression in colorectal cancers and liver metastatic lesions and other clinicopathological characteristics was analyzed. Univariate analysis and logistic multivariate regression analysis were adopted to discriminate risk factors of liver metastasis.

RESULTS

Nuclear β-catenin overexpression at the invasive front of the primary tumor in patients with liver metastasis is more evident than that in patients without liver metastasis (71.5% vs. 29.3%; P < 0.001). Nuclear β-catenin expression in primary tumors had a positive correlation with that in the matched metastatic lesions (r = 0.499, P < 0.001). Univariate and multivariate analyses indicated that overexpression of nuclear β-catenin at the invasive front in colorectal cancer correlated with liver metastasis.

CONCLUSIONS

Overexpression of nuclear β-catenin at the invasive front in colorectal cancer is strongly associated with liver metastasis and may be a promising predictor of liver metastasis.

Heterogeneous and complex rearrangements of chromosome arm 6q in chondromyxoid fibroma: delineation of breakpoints and analysis of candidate target genes

Chondromyxoid fibroma (CMF) is an uncommon benign cartilaginous tumor of bone usually occurring during the second decade of life. CMF is associated with recurrent rearrangements of chromosome bands 6p23-25, 6q12-15, and 6q23-27. To delineate further the role and frequency of the involvement of three candidate regions (6q13, 6q23.3 and 6q24) in the pathogenesis of CMF, we studied a group of 43 cases using a molecular cytogenetic approach. Fluorescence in situ hybridization with probe sets bracketing the putative breakpoint regions was performed in 30 cases. The expression level of nearby candidate genes was studied by immunohistochemistry and quantitative RT-PCR in 24 and 23 cases, respectively. Whole-genome copy number screening was performed by array comparative genomic hybridization in 16 cases. Balanced and unbalanced rearrangements of 6q13 and 6q23.3 occurred in six and five cases, respectively, and a hemizygous deletion in 6q24 was found in five cases. Two known tumor suppressor genes map to the latter region: PLAGL1 and UTRN. However, neither of these two genes nor BCLAF1 and COL12A1, respectively located in 6q23.3 and 6q13, showed altered expression. Therefore, although rearrangements of chromosomal regions 6q13, 6q23.3, and 6q24 are common in CMF, the complexity of the changes precludes the use of a single fluorescence in situ hybridization probe set as an adjunct diagnostic tool. These data indicate that the genetic alterations in CMF are heterogeneous and are likely a result of a cryptic rearrangement beyond the resolution level of combined binary ratio fluorescence in situ hybridization or a point mutation.

Phenotypic diversity in chondromyxoid fibroma reveals differentiation pattern of tumor mimicking fetal cartilage canals development: an immunohistochemical study

Chondromyxoid fibroma represents a rare benign cartilaginous tumor of young patients occurring in a subcortical metaphyseal location. The histogenesis of chondromyxoid fibroma has not yet been postulated, even though the conventional histology and recent immunohistochemical studies on phenotype of the mesenchymal cells and extracellular matrix components suggested its origin in immature cartilage. Therefore, we wished to compare the morphological pattern of immature cartilage tissue with chondromyxoid fibroma to investigate a possible developmental counterpart of chondromyxoid fibroma. Archival paraffin-embedded tissues from 4 fetal femora and 10 cases of chondromyxoid fibroma were analyzed simultaneously using histochemistry (safranin O) and established immunohistochemical antibodies (CD34, CD163, and smooth muscle actin). Vascularized cartilage canals growing into the fetal cartilage from the perichondrium displayed characteristic glomeruloid structures with central arterioles within the immature mesenchymal stroma and numerous superficial sinusoidal blood vessels accompanied by macrophage infiltration. Similarly, each case of chondromyxoid fibroma demonstrated admixture of two characteristic components: immature fibrous tissue of vascularized stroma with accumulation of macrophages in areas of superficial sinusoidal proliferation, and variable amounts of lobulated chondroid tissue. Based on the observed substantial morphological similarity between the cartilage canals and chondromyxoid fibroma, we suggest that the chondromyxoid fibroma represents a neoplasm originating from or mimicking the fetal cartilage canals within the immature cartilage.

Inactive Wnt/beta-catenin pathway in conventional high-grade osteosarcoma

Osteosarcoma is the most common malignant bone tumour, with a peak incidence in children and young adolescents, suggesting a role of rapid bone growth in its pathogenesis. The Wnt/beta-catenin pathway plays a crucial role in skeletal development and is indispensable for osteoblasts' lineage determination. Previous studies suggesting an oncogenic role for the Wnt/beta-catenin pathway in osteosarcoma were based on cytoplasmic staining of beta-catenin or the detection of one component of this pathway. However, those approaches are inappropriate to address whether the Wnt/beta-catenin pathway is functionally active. Therefore, in this study, we examined nuclear beta-catenin expression in 52 human osteosarcoma biopsies, 15 osteoblastomas (benign bone tumours), and four human osteosarcoma cell lines by immunohistochemistry. Furthermore, we modulated Wnt/beta-catenin pathway activity using a GIN (GSK3beta inhibitor) and evaluated its effect on cell growth and osteogenic differentiation. Absence of nuclear beta-catenin staining was found in 90% of the biopsies and all osteosarcoma cell lines, whereas strong nuclear beta-catenin staining was observed in all osteoblastomas. Wnt-luciferase activity was comparable to the negative control in all osteosarcoma cell lines. GIN stimulated the Wnt/beta-catenin pathway, as shown by translocation of beta-catenin into the nucleus and increased Wnt-luciferase activity as well as mRNA expression of AXIN2, a specific downstream target gene. Stimulation of the Wnt/beta-catenin pathway by GIN significantly reduced cell proliferation in the cell lines MG-63 and U-2-OS and enhanced differentiation in the cell lines HOS and SJSA-1, as shown by an increase in alkaline phosphatase (ALP) activity and mineralization. In contrast with the oncogenic role of the Wnt/beta-catenin pathway in osteosarcoma as previous studies suggested, here we demonstrate that this pathway is inactivated in osteosarcoma. Moreover, activation of the Wnt/beta-catenin pathway inhibits cell proliferation or promotes osteogenic differentiation in osteosarcoma cell lines. Our data suggest that loss of Wnt/beta-catenin pathway activity, which is required for osteoblast differentiation, may contribute to osteosarcoma development.

Immunolocalization of lactoferrin in cartilage-forming neoplasms

BACKGROUND

Lactoferrin (Lf) is an 80-kDa basic glycoprotein, a member of the transferrin family of iron-binding proteins. Lf immunoreactivity has been extensively investigated in many neoplastic tissues. Recently, Lf expression was documented in the osteoblastic lineage of bone-forming tumors as well as in osteoblasts of fetal bone.

METHODS

Lactoferrin (Lf) immunoexpression was investigated in 30 human cartilage-forming tumors [15 enchondromas, 6 osteochondromas, 3 chondroblastomas (CBL), 3 chondrosarcomas, and 3 chondromyxoid fibromas (CMF)] as well as in human normal bone specimens and cartilaginous tissues obtained at autopsy from 5 adults and 3 fetuses.In addition, the immunohistochemical expression of Ki-67 antigen was analyzed on parallel sections from the same specimens. Quantification of Lf immunoreactivity was performed by using an intensity distribution (ID) score.

RESULTS

Lf immunoexpression with a variable ID score was encountered exclusively in 3 of 3 chondroblastomas and in 3 of 3 chondromyxoid fibromas. Lf immunoreactivity in these tumors, in clear contrast with the Lf absence in enchondromas, osteochondromas, and chondrosarcomas, may suggest a different histogenesis of the former. In agreement with this histogenetic origin, we detected Lf in the chondroblasts and osteoblasts within the fetal tissue, whereas no immunoreactivity was found in the corresponding adult cells. No significant associations were found between the Lf immunoexpression and the Ki 67 LI of the tumors of our series.

CONCLUSIONS

The presence of Lf in neoplastic cells of CBL and CMF, as well as in fetal cartilaginous tissue, may reflect a less mature phenotype of these tumors.

Dedifferentiated peripheral chondrosarcomas: regulation of EXT-downstream molecules and differentiation-related genes

Dedifferentiated peripheral chondrosarcoma is a rare subtype of chondrosarcoma arising superimposed on the cartilage cap of a preexisting osteochondroma. It consists of two clearly defined components, a low-grade malignant, well-differentiated cartilage component and a high-grade non-cartilaginous sarcoma. Signaling pathways having a role in normal cartilage development were analyzed in these tumors, and compared with available data of other cartilaginous tumors. Sixteen well-characterized dedifferentiated peripheral chondrosarcomas were immunohistochemically analyzed for parathyroid hormone-like hormone (PTHLH)-BCL-2, fibroblastic growth factor (FGF), and transforming growth factor-beta signaling molecules, as well as matrix molecules and p53, comparing the chondrogenic component of dedifferentiated peripheral chondrosarcomas with the anaplastic component and with previously published data obtained from conventional grade I and II secondary peripheral chondrosarcomas. Results were correlated with clinical outcome. In the anaplastic component, various lines of differentiation could be found (collagen I (6/16), CD31 (1/16), smooth muscle actin (12/16), muscle-specific actin (12/16) and desmin (2/9)). Compared with the anaplastic component, the chondrogenic component of dedifferentiated peripheral chondrosarcomas shows more often expression of cyclin D1 (P=0.05), p53 (P=0.008), plasminogen activator inhibitor 1 (PAI-1) (P=0.005), and CD44 (P=0.030). Compared with secondary peripheral chondrosarcomas, more samples were positive in the chondrogenic component of dedifferentiated peripheral chondrosarcomas for FGF signaling (FGF receptor 3 P=0.000; bFGF P=0.003) and CD44 (P=0.000). Lower expression of BCL-2 (P=0.025) and absence of CD44v3 (P=0.000), a splice variant of CD44, was observed in the chondrogenic component of dedifferentiated peripheral chondrosarcomas compared with secondary peripheral chondrosarcomas. With regard to clinical data, PAI-1 expression in the chondrogenic component of dedifferentiated peripheral chondrosarcomas correlated with better survival (P=0.019). In conclusion, in the chondrogenic component of dedifferentiated peripheral chondrosarcomas, FGF signaling pathway is active, whereas PTHLH signaling seems to be low/downregulated. Interestingly, although the chondrogenic component of dedifferentiated peripheral chondrosarcoma is CD44+/CD44v3-, secondary peripheral chondrosarcomas is CD44-/CD44v3+, which suggest different splicing (preference). The prognostic value of PAI-1 in dedifferentiated peripheral chondrosarcomas might also be of interest for the more common dedifferentiated central chondrosarcomas.

Benign cartilaginous tumors of bone: from morphology to somatic and germ-line genetics

Benign cartilaginous tumors of bones, intrinsic to their name, are tumors forming cartilaginous matrix with a clinically benign behavior. In this group, we recognize osteochondromas, (en)chondromas, chondroblastomas, and chondromyxoid fibromas. This group includes common tumors, that is, osteochondroma and (en)chondroma as well as rare tumors such as chondroblastoma and chondromyxoid fibroma. Several benign and malignant tumors may mimic benign cartilaginous tumors of bones. We reviewed the main morphologic features and the differential diagnosis is discussed. The genetics of these tumors is intriguing ranging from single gene event (ie, EXT mutation in multiple osteochondromas) to heterogeneous rearrangements with no recurrent involved chromosomal regions such as in chondroblastoma. The main genetic findings are hereby reviewed.

The role of noncartilage-specific molecules in differentiation of cartilaginous tumors: lessons from chondroblastoma and chondromyxoid fibroma

BACKGROUND

Chondroblastoma (CB) and chondromyxoid fibroma (CMF) are benign tumors of bone morphologically recapitulating cartilage differentiation. CMF can resemble high-grade central chondrosarcoma (HGCCS) because of its cellular atypia. The mechanism that drives this morphologic spectrum of cartilage differentiation is unclear.

METHODS

CMFs and CBs were hybridized on a complementary DNA microarray that was enriched for cartilage-specific genes. Data were analyzed by Linear Model for Microarray Analysis and were compared with previous data on osteochondromas and HGCCS. Verification was performed in an extended series.

RESULTS

None of the 68 genes that were differentially expressed in CB versus CMF, including several extracellular matrix (ECM) and ECM-degradation genes, were related specifically to cartilage. Perlecan, versican, collagen 4A2 (Col4A2), and cell-cell adhesion genes, such as CD166, were significantly higher in CMF. Sixty genes were expressed differentially in CMF versus HGCCS. Higher expression levels of CD166, cyclin D1 (CCND1), and p16INK4A were observed in CMF.

CONCLUSIONS

The current findings indicated that differential expression of adhesion and ECM molecules, such as CD166, versican, perlecan, and Col4A2, may interfere with cartilaginous differentiation. The decreased expression of CCND1, p16INK4A, and CD166 in HGCCS reflects impairment of cell cycle progression and of cell-cell adhesions in malignant tumors and is of use in the differential diagnosis of CMF.

Molecular pathology of chondroid neoplasms: part 1, benign lesions

This two-part review presents an overview of the molecular findings associated with both benign and malignant chondroid neoplasms. This first part presents a brief review of methods in molecular pathology along with a review of the cytogenetic and molecular genetic findings in benign chondroid neoplasms. Clinical aspects of the various lesions are briefly discussed, and each tumor is illustrated with representative radiographic and pathologic images. Malignant chondroid neoplasms will be considered in the second part of this review.

Sarcoma derived from cultured mesenchymal stem cells

To study the biodistribution of MSCs, we labeled adult murine C57BL/6 MSCs with firefly luciferase and DsRed2 fluorescent protein using nonviral Sleeping Beauty transposons and coinfused labeled MSCs with bone marrow into irradiated allogeneic recipients. Using in vivo whole-body imaging, luciferase signals were shown to be increased between weeks 3 and 12. Unexpectedly, some mice with the highest luciferase signals died and all surviving mice developed foci of sarcoma in their lungs. Two mice also developed sarcomas in their extremities. Common cytogenetic abnormalities were identified in tumor cells isolated from different animals. Original MSC cultures not labeled with transposons, as well as independently isolated cultured MSCs, were found to be cytogenetically abnormal. Moreover, primary MSCs derived from the bone marrow of both BALB/c and C57BL/6 mice showed cytogenetic aberrations after several passages in vitro, showing that transformation was not a strain-specific nor rare event. Clonal evolution was observed in vivo, suggesting that the critical transformation event(s) occurred before infusion. Mapping of the transposition insertion sites did not identify an obvious transposon-related genetic abnormality, and p53 was not overexpressed. Infusion of MSC-derived sarcoma cells resulted in malignant lesions in secondary recipients. This new sarcoma cell line, S1, is unique in having a cytogenetic profile similar to human sarcoma and contains bioluminescent and fluorescent genes, making it useful for investigations of cellular biodistribution and tumor response to therapy in vivo. More importantly, our study indicates that sarcoma can evolve from MSC cultures.

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.