The Utility of MDM2 and CDK4 Immunohistochemistry and MDM2 FISH in Craniofacial Osteosarcoma

Combined SET7/9 and CDK4 inhibition act synergistically against osteosarcoma

Osteosarcoma is the most common malignant bone tumor. It has a poor prognosis because of a lack of therapeutic targets and strategies. The SET domain-containing lysine-specific methyltransferase, SET7/9, has various functions in different cancer types in tissue-type and signaling context-dependent manners. The role of SET7/9 in osteosarcoma cells is currently controversial and its potential as a therapeutic candidate in osteosarcoma is unknown. In the present study, SET7/9 inhibition or ablation suppressed osteosarcoma cell proliferation by causing G1 arrest. Mechanistically, SET7/9 inhibition disrupted the interaction between cyclin-dependent kinase 4 (CDK4) and cyclin D1, which affected CDK4-cyclin D1 complex function, leading to decreased phosphorylation of retinoblastoma protein. CDK4 was overexpressed in osteosarcoma tissues and was closely related to a poor prognosis in patients with osteosarcoma. We therefore hypothesized that SET7/9 inhibition might increase the sensitivity of osteosarcoma cells to CDK4 inhibitors, potentially decreasing the risk of adverse effects of CDK4 inhibitors. The combination of SET7/9 and CDK4 inhibition enabled dose reductions of both inhibitors and had a synergistic effect against osteosarcoma growth in vivo. Collectively, these findings indicate that SET7/9 plays an oncogenic role in osteosarcoma by regulating CDK4-cyclin D1 complex interaction and function. The combination of SET7/9 and CDK4 inhibition may thus provide a novel effective therapeutic strategy for osteosarcoma with no significant toxicity.

High-grade osteosarcoma arising in DCIA flap reconstruction after a prior resection of maxillar cemento-ossifying fibroma: A case report

Cemento-ossifying fibroma is a rare benign odontogenic tumour of the tooth-bearing jaws. Its concomitant occurrence with osteosarcoma, a malignant maxillofacial bone tumour, has never been described before. We present an uncommon case of a 43-year-old woman in whom a cemento-ossifying fibroma in the right maxilla was treated by resection and reconstruction using a deep circumflex iliac artery flap. During surgical prosthetic rehabilitation one-year post-operative, an osteosarcoma extending from the contralateral maxilla was coincidentally discovered in the deep circumflex iliac artery flap. The aim of this case report is to raise awareness on the extremely rare but possible simultaneous and independent occurrence of a cemento-ossifying fibroma and an osteosarcoma.

Carcinosarcoma of the deep lobe of the parotid gland in the parapharyngeal region: A case report

BACKGROUND

Salivary carcinosarcoma is an extremely rare tumor containing both malignant epithelial and mesenchymal constituents. This article reports a rare case of carcinosarcoma with salivary duct carcinoma and osteosarcoma as the tumor components. The clinicopathological characteristics, treatment, and prognosis are discussed in conjunction with the literature.

CASE SUMMARY

A 48-year-old man presented with a complaint of a mass in the right parotid region. Osteosarcoma was first considered for assessment by fine-needle aspiration cytology. Physical examination revealed a mass measuring approximately 4 cm × 3.5 cm × 3 cm. The mass, the whole lobe of the right parotid gland, and the right mandible were completely removed during surgery. Postoperative histopathology confirmed carcinosarcoma of the salivary gland.

CONCLUSION

A definite diagnosis of salivary gland carcinosarcoma can only be obtained after complete surgical resection.

Genomic Profiling of the Craniofacial Ossifying Fibroma by Next-Generation Sequencing

BACKGROUND

Ossifying fibroma (OF) of the craniofacial skeleton is a fibro-osseous lesion characterized by various patterns of bone formation in a cellular fibroblastic stroma. The molecular landscape of OF remains mostly unknown. There are a few known pathogenic abnormalities in OF, including HRPT2 mutations in conventional OF and SATB2 translocations in juvenile psammomatoid OF. On the other hand, conflicting reports exist regarding MDM2 gene amplification and chromosomal copy number alterations (CNA) in OF.

METHODS

Surgically removed biopsies and curettage specimens from OF patients were obtained. Clinical, radiographic, and pathologic features of tumors were reviewed. Genomic DNA was extracted from formalin-fixed, paraffin-embedded blocks of tumor tissue. Capture-based DNA next-generation sequencing targeting the coding regions 529 cancer genes and select introns was performed.

RESULTS

We identified 17 OF cases from 8 male and 8 female patients with mean age of 22 years (range 1-58 years). Nine case occurred in the gnathic bones and 8 in the extragnathic craniofacial bones. These cases included 3 juvenile psammomatoid OF, 6 conventional OF and 8 juvenile trabecular OF. Large-scale CNAs were present in 6 of 17 cases. Seven cases (41%) had focal amplifications including FOSB (n = 2, 11%), FOS (n = 4, 23%), COL1A1 (n = 4, 23%) and TBX3 (n = 5, 29%). Three cases (17%) had pathogenic CDC73 mutations. No cases showed focal MDM2 amplification.

CONCLUSIONS

Here, we provided a comprehensive molecular characterization of OF that reveals a heterogeneous genetic profile with occasional large-scale CNAs (n = 6, 35%). FOS, FOSB, and TBX3 genes that regulate AP-1 transcriptional complex are frequently altered in OF (n = 7, 41%), chiefly in juvenile trabecular OF. These genes encode transcription factors that act as downstream effectors of the MAP kinase signaling pathway. MDM2 amplification is an exceedingly rare event in OF, if present at all, so identification of this event should continue to raise concern for low-grade gnathic osteosarcoma. In summary, our findings suggest that OF represents a heterogeneous group of tumors at the genetic level but dysregulation of the AP-1 pathway may play a role in pathogenesis of juvenile trabecular OF.

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Diagnostic value of MDM2 RNA in situ hybridization for low-grade osteosarcoma: Consistency comparison of RNA in situ hybridization, fluorescence in situ hybridization, and immunohistochemistry

Detection of MDM2 gene amplification via fluorescence in situ hybridization (FISH) and MDM2 overexpression by immunohistochemistry (IHC) have been utilized for the diagnosis of low-grade osteosarcoma (LGOS). The aim of this study was to evaluate the diagnostic value of MDM2 RNA in situ hybridization (RNA-ISH) and compare this assay with MDM2 FISH and IHC in distinguishing LGOS from its histologic mimics. MDM2 RNA-ISH, FISH and IHC were performed on nondecalcified samples of 23 LGOSs and 52 control cases. Twenty (20/21, 95.2%) LGOSs were MDM2-amplified, and two cases failed in FISH. All control cases were MDM2-nonamplified. All 20 MDM2-amplified LGOSs and one MDM2-nonamplified LGOS harboring TP53 mutation and RB1 deletion showed positivity for RNA-ISH. Fifty of the 52 (96.2%) control cases were negative for RNA-ISH. The diagnostic sensitivity and specificity of MDM2 RNA-ISH were 100.0% and 96.2%, respectively. Nineteen of the 23 LGOSs were evaluated by MDM2 RNA-ISH and FISH in decalcified samples simultaneously. All decalcified LGOSs failed in FISH and most samples (18/19) were no staining in RNA-ISH. Fifteen (15/20, 75%) MDM2-amplified LGOSs were positive for IHC and 96.2% (50/52) of control cases were negative. The sensitivity of RNA-ISH (100%) was higher than that of IHC (75%). In conclusion, MDM2 RNA-ISH has great value for the diagnosis of LGOS, with excellent consistency with FISH and better sensitivity than IHC. Acid decalcification still has an adverse impact on RNA. Some MDM2-nonamplified tumors may show positivity for MDM2 RNA-ISH, which needs to be analyzed comprehensively in combination with clinicopathological features.

MDM2 Gene Amplification and Expression of MDM2 and CDK4 are Rare in Ossifying Fibroma of Craniofacial Bones

Ossifying fibroma of the craniofacial bones is a fibro-osseous lesion characterized by varied patterns of bone formation in a fibroblastic stroma. Ossifying fibroma is a putatively benign lesion with no reports of malignant transformation or metastasis. Differentiation from other fibro-osseous lesions can be challenging necessitating synthesis of clinical, radiological and pathological findings. The molecular pathogenesis of ossifying fibroma is poorly understood but recent studies have reported MDM2 gene amplification and chromosomal copy number changes in a subset of ossifying fibromas. MDM2 amplification in ossifying fibroma, if true, presents a diagnostic problem because this genetic event, at least among craniofacial fibro-osseous lesions, was previously considered specific for low-grade osteosarcoma. In the present study, we investigated the utility of MDM2 and CDK4 immunohistochemistry, and fluorescence in situ hybridization for MDM2 gene amplification, in the diagnosis of 44 craniofacial bone ossifying fibromas. Focal MDM2 and CDK4 nuclear immunoreactivity was found in 11 and 1 ossifying fibromas, respectively, but none demonstrated MDM2 amplification by fluorescence in situ hybridization. A single tumor displayed MDM2 amplification without nuclear immunoreactivity to either MDM2 or CDK4. Our data suggest that while focal MDM2 and CDK4 nuclear expression may be detected in a minority of ossifying fibromas, this expression does not correlate with MDM2 amplification. In addition, MDM2 amplification is extremely rare in ossifying fibroma so the detection of this genetic abnormality should continue to raise concern for osteosarcoma.

Clinicopathological value of the upregulation of cyclin-dependent kinases regulatory subunit 2 in osteosarcoma

Background

Cyclin-dependent kinase subunit 2 (CKS2) is a member of cyclin dependent kinase subfamily and the relationship between CKS2 and osteosarcoma (OS) remains to be further analyzed.

Methods

80 OS and 41 non-tumor tissue samples were arranged to perform immunohistochemistry (IHC) to evaluate CKS2 expression between OS and non-tumor samples. The standard mean deviation (SMD) was calculated based on in-house IHC and tissue microarrays, and exterior high-throughput datasets for further verification of CKS2 expression trend in OS. The effect of CKS2 expression on clinicopathological parameters of OS patients, and single-cell in OS tissues was analyzed through public high-throughput datasets and functional enrichment analysis was conducted for co-expression genes of CKS2 in accordance with weighted correlation network analysis.

Results

A total of 217 OS samples and 87 non-tumor samples (including tissue and cell line) were obtained from in-house IHC, microarrays and exterior high-throughput datasets. The analysis of integrated expression status demonstrated up-regulation of CKS2 in OS (SMD = 1.57, 95%CI [0.27–2.86]) and the significant power of CKS2 expression in distinguishing OS samples from non-tumor samples (AUC = 0.97 95%CI [0.95–0.98]). Clinicopathological analysis of GSE21257 indicated that OS patients with higher CKS2 expression was more likely to suffer OS metastasis. Although Kaplan–Meier curves showed no remarkable difference of overall survival rate between OS patients with high and low-CKS2, CKS2 was found up-regulated in proliferating osteosarcoma cells. Co-expression genes of CKS2 were mainly assembled in function and pathways such as cell cycle, cell adhesion, and intercellular material transport.

Conclusions

In summary, up-regulation of CKS2 expression in OS tissue was found through multiple technical approaches. In addition, scRNA-seq and co-expression analysis showed that CKS2 may have an impact on important biological process linked with cell cycle, cell adhesion, and intercellular material transport. Present study on CKS2 in OS indicated a promising prospect for CKS2 as a biomarker for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01234-8.

Role of MDM2, CDK4, BCL2, Parafibromin and Galectin 1 in Differentiating Osteosarcoma from its Benign Fibro-osseous Lesions

Benign fibro-osseous lesions (BFOLs) are a diverse group of lesions showing considerable degree of overlap with low grade osteosarcoma (LGOS). Further, de-differentiated osteosarcoma (DOS) is usually indistinguishable from conventional high-grade OS (COS) if LGOS foci are not identified. Thus, there is a need for adjunctive immunohistochemical markers to differentiate OS from benign FOLs as well as DOS from COS. This study evaluated the role of immunohistochemical expression of MDM2, CDK4, parafibromin, BCL-2 and Galectin-1 (Gal-1) in accurate characterization of benign FOLs and in differentiating them from OS. From our archives, we retrieved 101 tissue samples which were diagnosed as osteosarcoma (OS) /ossifying fibroma (OF) / fibrous dysplasia (FD) or fibrous hyperplasia (FH) and examined their immunohistochemical staining pattern with the aforementioned antibodies. MDM2 showed 100% specificity for diagnosing OS. CDK4 and Gal-1 showed linear increase in immunoexpression from benign BFOLs to OS. BCL-2 showed equivocal immunopositivity in OF and OS, but the positivity was higher than that observed in FD. The highest immunoexpression for parafibromin was seen in FD followed by OF and OS cases. Thus, MDM2 is most specific, and Gal-1 is most sensitive of all the markers studied in differentiating OS from benign mimics. Combination of these two markers can be used as an adjunct to conventional imaging and microscopy in accurate characterization of these lesions. Further MDM2 overexpression can differentiate DOS and COS.

SATB2 and MDM2 Immunoexpression and Diagnostic Role in Primary Osteosarcomas of the Jaw

Primary osteosarcomas of the jaw (OSJ) are rare, accounting for 6% of all osteosarcomas. This study aims to determine the value of SATB2 and MDM2 immunohistochemistry (IHC) in differentiating OSJ from other jawbone mimickers, such as benign fibro-osseous lesions (BFOLs) of the jaw or Ewing sarcoma of the jaw. Certain subsets of osteosarcoma harbor a supernumerary ring and/or giant marker chromosomes with amplification of the 12q13-15 region, including the murine double-minute type 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) genes. Special AT-rich sequence-binding protein 2 (SATB2) is an immunophenotypic marker for osteoblastic differentiation. Cases of OSJ, BFOLs (ossifying fibroma and fibrous dysplasia) of the jaw, and Ewing sarcoma of the jaw were retrieved from the Departments of Oral Pathology and Oral Medicine, Faculty of Dentistry, Obafemi Awolowo University and Lagos State University College of Medicine, Nigeria. All OSJ retrieved showed histologic features of high-grade osteosarcoma. IHC for SATB2 (clone EP281) and MDM2 (clone IF2), as well as fluorescence in situ hybridization (FISH) for MDM2 amplification, were performed on all cases. SATB2 was expressed in a strong intensity and diffuse staining pattern in all cases (11 OSJ, including a small-cell variant, 7 ossifying fibromas, and 5 fibrous dysplasias) except in Ewing sarcoma, where it was negative in neoplastic cells. MDM2 was expressed in a weak to moderate intensity and scattered focal to limited diffuse staining pattern in 27% (3/11) of cases of OSJ and negative in all BFOLs and the Ewing sarcoma. MDM2 amplification was negative by FISH in interpretable cases. In conclusion, the three cases of high-grade OSJs that expressed MDM2 may have undergone transformation from a low-grade osteosarcoma (LGOS). SATB2 is not a dependable diagnostic marker to differentiate OSJ from BFOLs of the jaw; however, it could serve as a valuable diagnostic marker in differentiating the small-cell variant of OSJ from Ewing sarcoma of the jaw, while MDM2 may be a useful diagnostic marker in differentiating OSJ from BFOLs of the jaw, especially in the case of an LGOS or high-grade transformed osteosarcoma.

Juvenile psammomatoid ossifying fibroma of the parietal bone and review of calvarial presentations: illustrative case

BACKGROUND

Juvenile psammomatoid ossifying fibroma (JPOF) is an uncommon benign fibro-osseous lesion that only rarely presents in the calvaria.

OBSERVATIONS

The authors reported a case of JPOF in the left parietal bone of a 20-year-old patient and reviewed the 27 other cases of JPOF occurring in the calvaria as reported in the literature.

LESSONS

JPOF rarely presents in the calvaria, and because diagnosis is a histopathologic one, clinicians should consider this entity when presented with a lytic, expansile mass on imaging. Little is known about the molecular mechanisms driving development of JPOF. MDM2 amplification may play a role, although this was not seen in the case presented herein.

The importance of clinical and radiological findings for the definitive histopathologic diagnosis of benign fibro-osseous lesions of the jaws: Study of 276 cases

PURPOSE

Benign fibro-osseous lesions (BFOLs) are heterogeneous intraosseous disease processes sharing overlapping histopathologic features and demonstrate a wide range of biological behavior. The aim of this study is to highlight the importance of clinical and radiological findings for the definitive histopathologic diagnosis of benign fibro-osseous lesions of the jaws.

MATERIALS AND METHODS

This is a cross-sectional retrospective study evaluating the three main groups of BFOLs: Cemento-osseous dysplasia, ossifying fibromas, and fibrous dysplasia. Previously diagnosed BFOL cases were searched for thoroughly from the archives of Istanbul University, Institute of Oncology, Department of Tumor Pathology in between 2005 and 2015. Clinical and radiological data of these cases were identified and recorded. The histopathologic features were reevaluated from the H&E-stained slides.

RESULTS

A total of 276 BFOL cases were identified and reevaluated for the study. The most common BFOL type was cemento-osseous dysplasia (n = 135), followed by cemento-ossifying fibroma (n = 77), fibrous dysplasia (n = 53) and juvenile ossifying fibroma (n = 11). The female/male ratio was 3.4:1 with a strong predilection for the 4th decade (n = 102). The mandible (n = 209) was the predominantly affected jaw. Prominent osteoblastic rimming around the bony lesion was commonly observed for cemento-ossifying fibroma (n = 60/77), followed by cemento-osseous dysplasia (n = 23/135). Predominant ossification patterns showed some differences among the groups. The most common radiological feature was the mixed radiolucent/radiopaque internal structure.

CONCLUSION

Our results document various clinical, radiological and histopathologic findings of BFOLs. Even some histopathologic differences are observed, clinical and radiographic correlation is mandatory prior to the definitive histopathologic diagnosis of BFOLs for the prevention of possible misdiagnoses or inappropriate treatments.

MDM2 Amplified Sarcomas: A Literature Review

Murine Double Minute Clone 2, located at 12q15, is an oncogene that codes for an oncoprotein of which the association with p53 was discovered 30 years ago. The most important function of MDM2 is to control p53 activity; it is in fact the best documented negative regulator of p53. Mutations of the tumor suppressor gene p53 represent the most frequent genetic change in human cancers. By overexpressing MDM2, cancer cells have another means to block p53. The sarcomas in which MDM2 amplification is a hallmark are well-differentiated liposarcoma/atypical lipomatous tumor, dedifferentiated liposarcoma, intimal sarcoma, and low-grade osteosarcoma. The purpose of this review is to summarize the typical clinical, histopathological, immunohistochemical, and genetic features of these tumors.

Professional diagnostic delay in osteosarcomas of the jaws

A series of 20 consecutive patients with an osteosarcoma of the jaws has been evaluated with regard to possible professional diagnostic delay. When set at an arbitrarily chosen period beyond three months, professional delay occurred in 15 patients, the mean being 21 months and the median 11 months. In five of the 15 patients a wrong diagnosis has been rendered on the biopsy specimen, being fibrous dysplasia (2x), osteoma (2x) and, in case of palatomaxillary swelling, pleomorphic adenoma (1x). In the other ten patients the initial clinicoradiographic features were misleading and apparently not indicative of a malignancy, except for one patient in whom a distinct widening of the periodontal ligament, as expressed on a periapical film, has been overlooked or not properly interpreted. It has not been possible to assess the possible influence of the delayed diagnosis on the prognosis.

Key words:Osteosarcoma of the jaws, diagnostic delay.

Osteosarcoma of the jaws: An overview of the pathophysiological mechanisms

Osteosarcoma (OS) is the most common cancer of bone. Jaw osteosarcoma (JOS) is rare and it differs from long-bone OS (LBOS) in terms of the time of onset (two decades later), lower metastatic spread, and better survival. OS is characterized by the proliferation of osteoblastic precursor cells and the production of osteoid or immature bone. OS arises from a combination of genetic aberrations and a favourable microenvironment. This local microenvironment includes bone cells, blood vessels, stromal cells, and immune infiltrates, all of which may constitute potential targets for anti-cancer drugs. Differences in the clinical and biological behaviour of JOS versus LBOS are likely to at least in part be due to differences in the microenvironment between the two sites. The present review provides a brief overview of the known pathophysiological parameters involved in JOS.