SATB2 is a novel marker of osteoblastic differentiation in bone and soft tissue tumours

SATB2 is an Emergent Biomarker of Anaplastic Thyroid Carcinoma: A Series with Comprehensive Biomarker and Molecular Studies

Anaplastic thyroid carcinoma (ATC) is a rare and aggressive thyroid malignancy typically comprised of undifferentiated tumor cells with various histologic morphologies, which makes the diagnosis challenging. These tumors commonly show loss of thyroglobulin and TTF1 with preservation of cytokeratin (67%) and Paired Box Gene 8 (PAX8) (55%) expression. Identification of a sensitive immunohistochemical stain to aid in the diagnosis of ATC would be beneficial. Immunohistochemistry (IHC) against special AT-rich sequence-binding protein 2 (SATB2) protein is a sensitive and specific marker expressed in colorectal adenocarcinoma and bone or soft tissue tumors with osteoblastic differentiation. However, SATB2 is also expressed in other sarcomatous/undifferentiated neoplasms lacking osteoblastic differentiation. Using quantitative reverse transcription PCR (RT-qPCR) we showed that there is variable expression of SATB2 mRNA expression in ATCs. To evaluate the role of SATB2 protein expression in ATC, we performed PAX8, SATB2, pancytokeratin (AE1/AE3 & CAM5.2), claudin-4 and TTF1 immunostaining on 23 cases. ATCs showed retained expression of PAX8 in 65% (15/23); SATB2 was detected in 74% (17/23); pancytokeratin was expressed in 65% (15/23); claudin-4 was expressed in 35% (8/23) and TTF1 showed expression in 13% (3/23) of cases. Furthermore, 83% (5/6) of ATCs which lacked SATB2 expression, retained PAX8 expression, while 88% (7/8) of the tumors without PAX8 expression were positive for SATB2. Differentiated follicular cell-derived thyroid cancers (n = 30), differentiated high grade thyroid carcinoma (n = 3), and poorly differentiated thyroid carcinoma (n = 8) were negative for SATB2 immunoreactivity. Next-generation selected cases detected the commonly identified oncogenic variants including those in BRAF, RAS, TP53, and TERT promoter. Overall, we hereby demonstrate that SATB2 IHC may be used to support the diagnosis of ATC.

Special AT-rich sequence-binding protein 2 immunohistochemistry in the diagnosis of osteosarcoma in dogs

Malignant osteoblasts can have markedly pleomorphic phenotypes and variable amounts of tumour-associated matrix, complicating the ability of pathologists to accurately differentiate osteosarcoma (OSA) from other types of neoplasms using only histopathology. Current immunohistochemical markers for animals have limited sensitivity and specificity in identifying OSA or produce inconsistent results. Immunohistochemistry (IHC) for special AT-rich sequence-binding protein 2 (SATB2) has been used in human medicine to aid in identification of normal and neoplastic osteoblasts, and the objective of this study was to determine whether this marker could also be useful for the diagnosis of canine OSA. Initially, SATB2 IHC was performed on eight samples from cases of well-differentiated canine OSA and on other tumour types for which OSA is a differential diagnosis, as well as on normal tissues, to assess sensitivity and cross-reactivity. Following confirmation that SATB2 is immunoreactive for normal and neoplastic canine osteoblasts and negative in other non-osseous mesenchymal cell types and organs, SATB2 IHC was tested on 123 cases of poorly differentiated malignant neoplasms as part of a panel with other immunohistochemical markers, as appropriate, based on histomorphology and differential diagnoses. The conclusion is that SATB2 IHC is a sensitive and specific marker for identifying canine OSA when used in a panel with other immunohistochemical markers and in conjunction with supportive clinical history.

SATB2 expression in oral sarcomatoid (spindle cell) squamous cell carcinoma: clinicopathologic and immunophenotypic characterization of 10 cases

OBJECTIVE

Sarcomatoid squamous cell carcinoma (sSCC) represents an uncommon histopathologic variant of squamous cell carcinoma (SCC). We examined the clinicopathologic and immunophenotypic characteristics, including SATB2 expression, of 10 cases of oral sSCCs.

STUDY DESIGN

Archived sSCC cases diagnosed during the period 2000 to 2023 were retrieved. Lesions lacking proper histomorphological features or adequate immunohistochemical confirmation were excluded. Patient age, sex, and lesion location were recorded. All cases were immunostained against SATB2 (Clone EP281; Cell Marque).

RESULTS

Ten oral sSCCs were identified (M:F ratio = 1.5:1; age range = 47-82 years, median = 74.5 years). The tongue was the most common anatomic site. Lesions presented as fungating or ulcerated, polypoid, and indurated masses. Microscopically, most tumors demonstrated an infiltrative population of atypical spindle cells organized in slender cords or fascicles. Rhabdoid/plasmacytoid morphology was observed in 3 cases. Immunohistochemically, all cases exhibited strong, focal-to-diffuse positivity for pancytokeratin, p63, and/or p40. Patchy, moderate-to-strong SATB2 staining was seen in 4 oral sSCCs, whereas 4 additional cases showed rare, weak-to-moderate expression.

CONCLUSIONS

Oral sSCC is uncommon and primarily exhibits spindled histomorphology, although rhabdoid/plasmacytoid features may be observed. A battery of epithelial and non-epithelial markers is required for proper diagnosis. Positive SATB2 immunostaining in oral sSCCs may pose a potential diagnostic pitfall, particularly in small biopsy specimens. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).

Pathogenetic and molecular classifications of soft tissue and bone tumors: A 2024 update

Soft tissue and bone tumors comprise a wide category of neoplasms. Their diversity frequently raises diagnostic challenges, and therapeutic options are continuously developing. The therapeutic success rate and long-term prognosis of patients have improved substantially due to new advances in immunohistochemical and molecular biology techniques. A fundamental contribution to these achievements has been the study of the tumor microenvironment and the reclassification of new entities with the updating of the molecular pathogenesis in the revised 5th edition of the Classification of Soft Tissue Tumors, edited by the World Health Organization. The proposed molecular diagnostic techniques include the well-known in situ hybridization and polymerase chain reaction methods, but new techniques such as copy-number arrays, multiplex probes, single-nucleotide polymorphism, and sequencing are also proposed. This review aims to synthesize the most recent pathogenetic and molecular classifications of soft tissue and bone tumors, considering the major impact of these diagnostic tools, which are becoming indispensable in clinicopathological practice.

Primary palatal sarcoma exhibiting EWSR1::RORß fusion: a first case report and literature review

In this report, a tumor exhibited EWSR1::RORß gene fusion, to our knowledge, is the first such reported case. The Ewing sarcoma breakpoint region 1 gene (EWSR1) is known to be associated with several soft tissue tumors although its specific role remains unclear. Its fusion with a member of the ETS family, including FLI1 and ERG, results in Ewing sarcoma, and its fusion with other genes unrelated to the ETS family, including NFATC2 and PATZ1, results in round cell sarcoma with EWSR1-non-ETS fusions, previously referred to as Ewing-like sarcoma. RORß encodes retinoic acid-related orphan receptor ß, a nuclear receptor (NR), and is involved in circadian rhythm modulation and cancer regulation. The specific role of RORß in tumorigenesis remains unclear; however, this case report suggests that it may form part of a new tumorigenic entity.

Evaluation of Lineage/Site-specific Nuclear Immunohistochemical Markers SATB2, Cyclin D1, SALL4, and BCOR in High-grade Endometrial Carcinomas

Poorly differentiated malignant neoplasms involving the gynecologic tract routinely include a poorly differentiated endometrial carcinoma (EC) in the differential diagnosis. Some nuclear lineage/site-specific immunohistochemical markers are utilized in this diagnostic setting including SATB2, cyclin D1, SALL4, and BCOR, but their specificity and use in small samples are not clear across the spectrum of ECs. Cases of undifferentiated/dedifferentiated endometrial carcinomas (UEC/DDEC), clear cell carcinoma (CCC), uterine serous carcinoma (USC), FIGO grade 3 endometrial endometrioid carcinoma (EEC), and uterine carcinosarcoma (UCS) were identified and diagnoses confirmed. Whole-section immunohistochemical stains for SATB2, cyclin D1, SALL4, BCOR, and PAX8 were performed. A total of 113 cases were utilized: 15 CCC, 26 EEC, 19 UCS, 22 USC, and 31 UEC/DDEC. Cases were distributed across both low (49%) and high (51%) FIGO clinical stages. SATB2 was expressed by UCS (8/19, 42%), EEC (10/26, 38%), UEC/DDEC (11/30, 37%), and USC (6/22, 27%). Cyclin D1 was expressed by EEC (24/26, 92%), USC (17/22, 77%), UEC/DDEC (15/20 EEC component, 75%; 22/30 UEC, 73%), UCS (10/16 carcinoma, 63%; 11/19 sarcoma, 58%), and CCC (8/15, 53%). SALL4 was expressed most frequently by UEC/DDEC (12/30, 40%), but also USC (7/22, 32%), EEC (5/26, 19%), and UCS (4/16 carcinoma, 25%; 3/19 sarcoma, 16%). BCOR was expressed at low levels in 2 USC, 2 UEC/DDEC, and 2 UCS. PAX8 was generally positive but showed lower expression in UEC/DDEC (17/30, 57%) and in the sarcomatous portions of UCS (6/19, 32%). SATB2, cyclin D1, SALL4, and BCOR stain variable numbers of poorly-differentiated EC and must be carefully interpreted within morphologic and clinical context.

Primary cutaneous extraskeletal osteosarcoma: a series of 16 cases

Extraskeletal osteosarcoma (EOS) is a high grade soft tissue tumour characterised by the production of malignant osteoid, without attachment/involvement of underlying bone/periosteum. Rarely, EOS presents as a cutaneous tumour. The clinical behaviour of primary cutaneous EOS (PC-EOS) remains incompletely characterised. Herein we present the largest case series of PC-EOS reported to date. Sixteen PC-EOS cases from the archives/consultation files were retrieved (male:female 1:1; age 31-96 years, mean age 66 years). The tumours measured 1-10 cm (mean 3.2 cm) and were located on the lower extremity (7), head (6), upper extremity (2), and trunk (1). They consisted of pleomorphic, spindled-to-epithelioid cells, with fascicular, nodular, or sheet-like growth patterns and foci of malignant osteoid. Immunohistochemistry did not reveal specific lines of differentiation, and there was no evidence of other tumour types. A literature review was conducted to identify all well characterised cases of PC-EOS. A combined analysis of present and past cases was performed to determine overall trends in clinical characteristics and outcomes. The mean follow-up period was 23.9 months, during which 67.5% of patients experienced progression-free survival and 18% of patients died of disease. Rates of local recurrence and metastasis were 10% and 25%, respectively, approximately double past estimates. These data suggest that the prognosis of PC-EOS is less favourable than previously thought. The differential diagnosis includes benign entities (e.g., ossifying pyogenic granuloma) and malignant neoplasms with heterologous osteosarcomatous differentiation (e.g., carcinosarcoma, transdifferentiated melanoma). Wide excision remains the standard of care, and the role of chemotherapy and radiation remains inconclusive. Recognition of this rare entity can facilitate prompt diagnosis and appropriate treatment.

Expression of SATB2 in primary cutaneous sarcomatoid neoplasms: a potential diagnostic pitfall

SATB2 can be used as an immunohistochemical marker for osteoblastic differentiation. The differential diagnosis of a cutaneous sarcomatoid neoplasm sometimes includes osteosarcoma when the tumour concomitantly involves the skin, soft tissue, and bone, or when there is a past medical history of osteosarcoma. As the utility of SATB2 immunohistochemistry in these scenarios was unclear, we aimed to determine the frequency and the pattern of SATB2 expression in a variety of cutaneous sarcomatoid neoplasms. SATB2 expression by immunohistochemistry was evaluated by intensity (0-3) and extent (0-100%) of staining to generate an h-score for each case. Expression levels were classified into high-positive (h-score ≥100), low-positive (20-99), and negative (<20) groups. Positive SATB2 expression was observed in 18/23 (78%) atypical fibroxanthomas (AFX), 10/19 (53%) pleomorphic dermal sarcomas, 9/20 (45%) cutaneous sarcomatoid squamous cell carcinomas, 14/39 (36%) sarcomatoid melanomas, 2/13 (15%) poorly differentiated cutaneous angiosarcomas, 10/17 (59%) high-grade cutaneous leiomyosarcomas, and 7/8 (88%) osteosarcoma controls. With the exception of AFX, all cutaneous neoplasms showed significantly lower average h-scores than osteosarcoma. AFX gave the highest average h-score (71) and percentage of high-positive cases (48%) among all examined cutaneous neoplasms. Only two (1.5%) of all cutaneous cases showed strong intensity of staining. Common SATB2 expression in various cutaneous sarcomatoid neoplasms poses a potential diagnostic pitfall when the differential diagnosis includes osteosarcoma. Requirement of strong staining and a high-positive h-score improves the specificity of SATB2 in differentiating these tumours from osteosarcoma.

Mesenchymal lesions of the breast

Mesenchymal lesions of the breast are a heterogeneous range of entities with diverse clinical, histological, and molecular features, as well as biological behaviour. Their morphologic overlap with non-mesenchymal lesions (such as metaplastic carcinoma and phyllodes tumour) and relative rarity also pose significant diagnostic challenges. In this review, we summarize the salient features of selected mesenchymal lesions of the breast, emphasizing those that are the most common and problematic. Vascular, fibroblastic/myofibroblastic, adipocytic, and smooth muscle lesions are each covered with regard to their clinicopathological features and differential diagnosis, while recent advances and the role of immunohistochemistry and molecular tests are also highlighted.

Transformation of Cemento-Ossifying Fibroma into Osteosarcoma after Radiotherapy and Nine Endoscopic Surgeries

Cemento-ossifying fibromas (COFs) are benign fibro-osseous tumors usually found in the mandible and maxilla that can show malignancy in rare situations. COFs usually grow slowly and asymptomatically until they produce local bulges, pain, headaches, and visual impairment, and have a Ki-67 index within 3%, even in aggressive and recurrent cases. Surgical resection can usually provide a satisfactory prognosis. However, no cases of COF transforming into osteosarcoma have been reported. We present a case of COF involving a 58-year-old woman whose initial symptom was hearing loss in the right ear accompanied by tinnitus. Enhanced magnetic resonance imaging revealed a 3.1 cm x 3.2 cm mass centered on the right pterygoid process of the sphenoid bone. Postoperative pathology revealed a COF with a high Ki-67 index (8%-10%). Over the next two years, the tumor relapsed repeatedly. The patient underwent nine endoscopic surgeries and radiotherapy. The sixth postoperative biopsy showed that the COF had transformed into an osteosarcoma. The patient subsequently experienced respiratory and cardiac arrests and was receiving treatment in the intensive care unit with a poor prognosis at the time of writing this manuscript. Thus, a high Ki-67 index may be a risk factor for malignant transformation for COFs.

Malignant Brain and Spinal Tumors Originating from Bone or Cartilage

Malignant bone tumors affecting the brain and spine are a rare and exceedingly difficult-to-treat group of diseases. Most commonly consisting of chordoma and chondrosarcoma, these tumors also include giant-cell tumors and osteosarcomas. This chapter will cover the background, epidemiology, genetics, molecular biology, histopathology, radiographic features, clinical manifestations, therapeutic approaches, and clinical management of each entity.

Ewing and Ewing-like sarcomas: A morphological guide through genetically-defined entities

The fifth edition of the World Health Organization classification of soft tissue and bone tumors redefined Ewing sarcoma by fusions between EWSR1/FUS and ETS family of transcription factors, and recognized three tumor groups among Ewing-like sarcoma: CIC-rearranged sarcoma, sarcoma with BCOR genetic alterations, and round cell sarcoma with EWSR1::non-ETS fusions. Although this classification underscores the critical role of molecular genetics in the diagnosis of small round cell sarcoma, each entry is recognized as a specific entity not only because they have different genetics but because their phenotypes are distinct and reasonably robust to support the diagnosis. This review focuses on the morphological aspects of Ewing sarcoma and a subset of Ewing-like sarcomas (CIC-rearranged sarcoma, BCOR-associated sarcoma, and EWSR1::NFATC2 sarcoma) for which phenotypic characteristics have been well established. Classic histological findings, uncommon variations, and recurrent diagnostic pitfalls are addressed, along with the utility of recently developed immunohistochemical markers (NKX2.2, PAX7, ETV4, BCOR, CCNB3, and NKX3.1). Phenotypic expertise would significantly expedite the diagnostic process and complement (or sometimes outperform) genetic testing, even in well-resourced settings. Morphological knowledge plays an even more substantial role in facilities that do not have easy access to molecular testing.

Expression of SATB2, RUNX2, and SOX9 and possible osteoblastic and chondroblastic differentiation in chondroblastoma

Chondroblastoma (CB) is histologically characterized by oval to polygonal-shaped mononuclear neoplastic cells, multinucleated osteoclastic giant cells, and eosinophilic matrix with occasional calcification. Genetically, the majority of CBs harbor H3F3B p.K36M mutation. Despite the historical nomenclature, it has been reported that the matrix of CB is similar to osteoid rather than true cartilage; however, it remains unclear whether neoplastic cells in CB have the potential for osteoblastic differentiation. To clarify this issue, we immunohistochemically examined the expression of osteogenic and chondrogenic markers (SATB2, RUNX2, p63, and SOX9) as well as H3K36M mutant protein in 33 cases of CB. All 33 cases of CB were positive for H3K36M, while SATB2, RUNX2, p63, and SOX9 were expressed in 30/33 (91%), 33/33 (100%), 29/33 (88%), and 31/32 (97%) CB cases, respectively. Our immunohistochemical results suggest that neoplastic cells in CB frequently express both osteogenic and chondrogenic markers and may have an intermediate feature of osteoblastic and chondroblastic nature.

Loss of SATB2 expression correlates with cytokeratin 7 and PD-L1 tumor cell positivity and aggressiveness in colorectal cancer

Colorectal carcinoma (CRC) is a disease that causes significant morbidity and mortality worldwide. To improve treatment, new biomarkers are needed to allow better patient risk stratification in terms of prognosis. This study aimed to clarify the prognostic significance of colonic-specific transcription factor special AT-rich sequence-binding protein 2 (SATB2), cytoskeletal protein cytokeratin 7 (CK7), and immune checkpoint molecule programmed death-ligand 1 (PD-L1). We analyzed a cohort of 285 patients with surgically treated CRC for quantitative associations among the three markers and five traditional prognostic indicators (i.e., tumor stage, histological grade, variant morphology, laterality, and mismatch-repair/MMR status). The results showed that loss of SATB2 expression had significant negative prognostic implications relative to overall survival (OS) and cancer-specific survival (CSS), significantly shortened 5 years OS and CSS and 10 years CSS in patients with CRC expressing CK7, and borderline insignificantly shortened OS in patients with PD-L1 + CRC. PD-L1 showed a significant negative impact in cases with strong expression (membranous staining in 50-100% of tumor cells). Loss of SATB2 was associated with CK7 expression, advanced tumor stage, mucinous or signet ring cell morphology, high grade, right-sided localization but was borderline insignificant relative to PD-L1 expression. CK7 expression was associated with high grade and SATB2 loss. Additionally, a separate analysis of 248 neoadjuvant therapy-naïve cases was performed with mostly similar results. The loss of SATB2 and CK7 expression were significant negative predictors in the multivariate analysis adjusted for associated parameters and patient age. In summary, loss of SATB2 expression and gain of CK7 and strong PD-L1 expression characterize an aggressive phenotype of CRC.

Special AT-rich sequence-binding protein 2 (SATB2) in the differential diagnosis of osteogenic and non-osteogenic bone and soft tissue tumors

Background

The diagnosis of osteosarcoma (OSA) depends on clinicopathological and radiological correlation. A biopsy is considered the gold standard for OSA diagnosis. However, since OSA is a great histological mimicker, diagnostic challenges exist. Immunohistochemistry (IHC) can serve as an adjunct for the histological diagnosis of OSA. Special AT-rich sequence-binding protein 2 (SATB2) was recently described as a reliable adjunct immunohistochemical marker for the diagnosis of OSA.

Methods

We investigated the IHC expression of SATB2 in 95 OSA and 100 non-osteogenic bone and soft tissue tumors using a monoclonal antibody (clone EPNCIR30A). The diagnostic utility of SATB2 and correlation with clinicopathological parameters were analyzed.

Results

SATB2 IHC was positive in 88 out of 95 cases (92.6%) of OSA and 50 out of 100 cases (50.0%) of primary non-osteogenic bone and soft tissue tumors. Of the 59 bone tumors, 37 cases (62.7%) were positive for SATB2, and of the 41 soft tissue tumors, 13 cases (31.7%) were positive for SATB2. The sensitivity of SATB2 as a diagnostic test was 92.6%, specificity 50%, positive predictive value 63.8%, and negative predictive value 87.7%.

Conclusions

Although SATB2 is a useful diagnostic marker for OSA, other clinical, histological and immunohistochemical features should be considered for the interpretation of SATB2.

SATB2 Expression in Undifferentiated Pleomorphic Sarcomas of Bone

OBJECTIVES

SATB2 is a transcriptional regulator that plays an important role in osteoblastic differentiation. We examined the prevalence and potential significance of SATB2 expression in undifferentiated pleomorphic sarcoma (UPS) of bone.

METHODS

We examined 38 cases of bone UPS without osteoid. The male-to-female ratio was 1:1.4, with a median age of 48 years (range, 23-83 years). Tumors occurred primarily in the femur (n = 8) and ilium (n = 8), with a median tumor size of 9.5 cm (range, 1.8-27.0 cm). The median follow-up was 24.7 months (range, 2-82 months): 11 patients developed local recurrences, and 18 patients had metastases, mainly to lung and bone.

RESULTS

SATB2 expression (nuclear labeling ≥5%) was seen in 21 of 38 (55%) cases: 5 with focal (nuclear labeling 5%), 11 with patchy (nuclear labeling 5%-50%), and 5 with diffuse (nuclear labeling ≥50%) staining. Among this group, diffuse SATB2 expression demonstrated superior metastasis-free survival (P = .036) and event-free survival (P = .024). For comparison, 100 soft tissue UPS were stained; the majority were negative (75/100 [75%]).

CONCLUSIONS

UPS of bone demonstrated more frequent SATB2 expression compared with its soft tissue counterpart. In this series, diffuse SATB2 expression in UPS of bone was associated with better outcomes. Additional studies are still needed to determine its significance.

SOX9 and SATB2 Immunohistochemistry Cannot Reliably Distinguish Between Osteosarcoma and Chondrosarcoma on Biopsy Material

INTRODUCTION

Limited tissue in biopsies of malignant bone lesions can preclude definitive subclassification, especially when cellular or matrix elements are sparse, absent, or confounding. It is uncertain whether IHC for SOX9 (marker of chondrogenesis) and SATB2 (marker of osteoblastic differentiation) may be discriminatory tools towards osteosarcoma and chondrosarcoma.

METHODS

This study interrogated the pre-resection biopsies of a cohort of osteosarcoma and chondrosarcoma with SATB2 and SOX9 in tandem, to assess their value as diagnostic adjuncts as well as their concordance with final resection diagnoses.

RESULTS

SATB2 was expressed more frequently in osteosarcoma (46/53, 86%) compared to chondrosarcoma (9/18, 50%); SOX9 was expressed in high frequencies in both osteosarcoma (52/53, 98%) and chondrosarcoma (17/18, 94%), and SATB2 and SOX9 were co-expressed in both osteosarcoma (46/53, 89%) and chondrosarcoma (8/18, 44%).

CONCLUSIONS

There exists significant overlap in expression of SATB2 and SOX9 in osteosarcoma and chondrosarcoma. These markers are not expressed in a distribution that is unique enough for application towards this particular diagnostic differential.

circ-Iqsec1 induces bone marrow-derived mesenchymal stem cell (BMSC) osteogenic differentiation through the miR-187-3p/Satb2 signaling pathway

BACKGROUND

Bone marrow-derived mesenchymal stem cells (BMSCs) are general progenitor cells of osteoblasts and adipocytes and they are characterized as a fundamental mediator for bone formation. The current research studied the molecular mechanisms underlying circRNA-regulated BMSC osteogenic differentiation.

METHODS

Next-generation sequencing (NGS) was employed to study abnormal circRNA and mRNA expression in BMSCs before and after osteogenic differentiation induction. Bioinformatics analysis and luciferase reporting analysis were employed to confirm correlations among miRNA, circRNA, and mRNA. RT-qPCR, ALP staining, and alizarin red staining illustrated the osteogenic differentiation ability of BMSCs.

RESULTS

Data showed that circ-Iqsec1 expression increased during BMSC osteogenic differentiation. circ-Iqsec1 downregulation reduced BMSC osteogenic differentiation ability. The present investigation discovered that Satb2 played a role during BMSC osteogenic differentiation. Satb2 downregulation decreased BMSC osteogenic differentiation ability. Bioinformatics and luciferase data showed that miR-187-3p linked circ-Iqsec1 and Satb2. miR-187-3p downregulation or Satb2 overexpression restored the osteogenic differentiation capability of BMSCs post silencing circ-Iqsec1 in in vivo and in vitro experiments. Satb2 upregulation restored osteogenic differentiation capability of BMSCs post miR-187-3p overexpression.

CONCLUSION

Taken together, our study found that circ-Iqsec1 induced BMSC osteogenic differentiation through the miR-187-3p/Satb2 signaling pathway.

Breast Metaplastic Carcinoma With Osteosarcomatous Differentiation: A Case Report and literature Review

Metaplastic breast carcinoma (MBCs) is a rare heterogeneous group of malignancies. Herein, we report a case of metaplastic breast carcinoma, which had 2 components. One of them was typical invasive ductal carcinoma (IDC), the other one was presenting as osteosarcoma with lots of immature trabeculae. The results of immunohistochemistry showed different presentations between them. The majority of MBCs show triple-negativity for ER, PR, and HER-2 and are thus associated with poor prognosis. Our report shows that, it is necessary to describe the proportion of the components and the presentations of immunohistochemistry in the diagnosis, which will be important to develop specific and effective therapies.

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.

Primary cutaneous extraskeletal osteosarcoma of the pretibial leg: A case report and summary of the literature

Primary cutaneous extraskeletal osteosarcoma is a rare tumor, with fewer than thirty known cases worldwide. We report the case of a 60-year-old female who presented with a solitary 3 mm right pretibial nodule. She had no known comorbidities, trauma to the area, nor prior malignancy. The biopsy specimen showed abundant mineralized osteoid, in which pleomorphic and spindled cells with anaplastic features were embedded. The osteoid matrix in this case contained overtly malignant cells, with frequent mitotic figures, as well as multinucleated giant cells. Immunohistochemistry and imaging led to the conclusion that this nodule represented a primary cutaneous extraskeletal osteosarcoma. The previously reported cases are variable in location, size, gross appearance, and clinical course. The prognosis of osteosarcoma is typically poor, with aggressive behavior; this, however, may be less severe in these strictly cutaneous tumors, though additional follow-up would be beneficial to determine long-term outcomes for the known cases. Ultimately, despite the fact that this is an extremely rare entity, primary cutaneous extraskeletal osteosarcomas should be considered when relevant. This article is protected by copyright. All rights reserved.

Ethanol exposure of human pancreatic normal ductal epithelial cells induces EMT phenotype and enhances pancreatic cancer development in KC (Pdx1-Cre and LSL-KrasG12D ) mice

Alcohol is a risk factor for pancreatic cancer. However, the molecular mechanism by which chronic alcohol consumption influences pancreatic cancer development is not well understood. We have recently demonstrated that chronic ethanol exposure of pancreatic normal ductal epithelial cells (HPNE) induces cellular transformation by generating cancer stem cells (CSCs). Here, we examined whether chronic ethanol treatment induces epithelial–mesenchymal transition in HPNE cells and promotes pancreatic cancer development in KC (Pdx1‐Cre, and LSL‐Kras^G12D) mice. Our data demonstrate that chronic ethanol exposure of HPNE cells induces SATB2 gene and those cells became highly motile. Ethanol treatment of HPNE cells results in downregulation of E‐Cadherin and upregulation of N‐Cadherin, Snail, Slug, Zeb1, Nanog and BMI‐1. Suppression of SATB2 expression in ethanol‐transformed HPNE cells inhibits EMT phenotypes. KC mice fed with an ethanol‐containing diet show enhanced pancreatic cancer growth and development than those fed with a control diet. Pancreas isolated from KC mice fed with an ethanol‐containing diet show higher expression of stem cell markers (CD133, CD44, CD24), pluripotency‐maintaining factors (cMyc, KLF4, SOX‐2, and Oct‐4), N‐Cadherin, EMT‐transcription factors (Snail, Slug, and Zeb1), and lower expression of E‐cadherin than those isolated from mice fed with a control diet. Furthermore, pancreas isolated from KC mice fed with an ethanol‐containing diet show higher expression of inflammatory cytokines (TNF‐α, IL‐6, and IL‐8) and PTGS‐2 (COX‐2) gene than those isolated from mice fed with a control diet. These data suggest that chronic alcohol consumption may contribute to pancreatic cancer development by generating inflammatory signals and CSCs.

Benign Bone-Forming Tumors

Benign bone-forming tumors comprise osteomas, osteoid osteomas, and osteoblastomas. Osteomas affect a wide age range and are usually discovered incidentally. They occur predominantly in the craniofacial skeleton and are classically composed of compact bone. Osteoid osteomas and osteoblastomas are painful lesions occurring in young patients. They are morphologically similar and characterized by FOS gene rearrangement and c-FOS expression at a protein level. Osteoid osteomas are usually smaller than 2 cm in maximum dimension with limited growth potential; osteoblastomas are larger than 2 cm and may be locally aggressive. Histologically both are composed of anastomosing trabeculae of woven bone.

A case of a large solitary fibrous tumor in the thigh, displaying NAB2ex4-STAT6ex2 gene fusion

A solitary fibrous tumor (SFT) is documented in several body sites. However, there are few reports on the radiological and corresponding histopathological, including immunohistochemical, features of SFT in the lower extremities. A 58-year-old male presented with a lump in his right thigh of 6 months duration. Plain radiograph revealed a soft tissue lesion in his right thigh, involving the adjacent mid-diaphysis and showing focal cortical thickening and calcification. Magnetic resonance imaging scans displayed two well-defined, T1-isointense and T2 heterogeneously hyperintense lesions, measuring together 15 cm in the intermuscular plane and the juxtacortical location along the mid-diaphyseal region of the right femur. Radiologically, the differential diagnoses considered were undifferentiated pleomorphic sarcoma and synovial sarcoma. Microscopic examination of the core biopsy and the resected tumor revealed a tumor composed of cells with oval to spindle-shaped nuclei in a variably collagenized stroma, including hyalinized blood vessels and focal dystrophic calcification. Mitotic figures were 4/10 high power fields. Immunohistochemically, the tumor cells were positive for CD34, BCL2, and STAT6. Diagnosis of malignant SFT was offered. The tumor displayed NAB2ex4-STAT6ex2 gene fusion on molecular testing. This constitutes a relatively uncommon case report of a large SFT in the thigh, including its radiological and pathological features, confirmed by STAT6 immunostaining. An SFT should be considered in cases of slow-growing, well-defined soft tissue tumors, which are isointense on T1 and heterogeneously hyperintense on T2-weighted sequences, and display calcification and cortical thickening of the adjacent bones. Various differential diagnoses and their treatment-related implications in such cases are discussed herewith.

Avenues of research in dietary interventions to target tumor metabolism in osteosarcoma

Osteosarcoma (OS) is the most frequent primary bone cancer, affecting mostly children and adolescents. Although much progress has been made throughout the years towards treating primary OS, the 5-year survival rate for metastatic OS has remained at only 20% for the last 30 years. Therefore, more efficient treatments are needed. Recent studies have shown that tumor metabolism displays a unique behavior, and plays important roles in tumor growth and metastasis, making it an attractive potential target for novel therapies. While normal cells typically fuel the oxidative phosphorylation (OXPHOS) pathway with the products of glycolysis, cancer cells acquire a plastic metabolism, uncoupling these two pathways. This allows them to obtain building blocks for proliferation from glycolytic intermediates and ATP from OXPHOS. One way to target the metabolism of cancer cells is through dietary interventions. However, while some diets have shown anticancer effects against certain tumor types in preclinical studies, as of yet none have been tested to treat OS. Here we review the features of tumor metabolism, in general and about OS, and propose avenues of research in dietary intervention, discussing strategies that could potentially be effective to target OS metabolism.

SATB2 Immunoexpression in Peripheral Ossifying Fibroma and Peripheral Odontogenic Fibroma

Peripheral ossifying fibromas (POFs) and peripheral odontogenic fibromas (POdFs) appear clinically similar but of different histogenesis. The novel marker SATB2 is involved in regulation of osteoblastic differentiation and phenotype. However, SATB2 expression has not been previously explored in POFs and POdFs. Given the potential for mineralized tissue formation in POFs and POdFs, and to more clarify the phenotype of the lesional cells, this study was aimed to immunohistochemically investigate SATB2 expression in POFs and POdFs. Fourteen cases of POF and POdF (7 cases each) were selected, stained for SATB2 immunohistochemically, and scored according to the percentage of positive lesional cells (0, no staining; 1 +, < 5%; 2 +, 5-25%; 3 +, 26-50%; 4 +, 51-75%; and 5 +, 76-100%), and the intensity of staining was graded as weak, moderate, or strong. The control group included the inflammatory fibrous hyperplasia-like area present in two cases, 1 case fibroma, and 1 case giant cell fibroma. Moderate to strong, and diffuse SATB2 nuclear immunoreactivity was detected in the lesional cells of all cases of POFs and POdFs with variable scores; 3-5 + for the POFs and 3-4 + for the POdFs (P = 0.101). The distribution of staining was more prominent in those lesional cells associated with the osteoid/calcification in the cases of POFs. No staining was noted in the control group. The lesional cells in both POFs and POdFs express SATB2 and may exhibit the osteoblastic-like phenotype. SATB2 staining may be useful for diagnosis of subsets of POFs with minimal or absent calcification and some POdFs with unidentifiable odontogenic epithelium.

Melanoma with osseous or chondroid differentiation: a report of eight cases including SATB2 expression and mutation analysis

Melanoma can present with osteocartilaginous differentiation, however few reports exist on this rare subtype. We present eight cases of melanoma with osteocartilaginous differentiation to highlight its clinical, pathological and molecular features. The cases showed no association with gender (5 males and 3 females) or age (range 23-84 years). Cases included both primary melanomas and distant metastases (6 and 2, respectively), with the majority arising from cutaneous sites (7/8) and the remaining case from a mucosal site. Tumour-infiltrating lymphocyte (TIL) score ranged from 0 to 3 (median 1), and 2/8 lesions had evidence of inflammatory changes or antecedent trauma. No recurrent mutations were found in the tumours by next generation sequencing, and the mutations observed were typical of melanoma rather than osteosarcomatous lesions. The majority of tumours stained positive for melanoma markers including S100, HMB45, Melan-A, SOX10 and MITF. Staining of the osteoblastic marker SATB2 varied from negative to widespread positive. We demonstrate that melanomas with osteocartilaginous differentiation are heterogeneous in presentation and are not typified by a recurrent mutation in cancer associated genes. Where uncertainty exists in diagnosing an osteocartilaginous lesion, a diagnosis of melanoma can be supported by the presence of genomic mutations typical of melanoma such as BRAF, NRAS and NF1, and IHC staining positive for S100, HMB45, Melan-A, SOX10 and MITF. SATB2 may be positive in these lesions and thus should not be used to rule out melanoma.

Recurrent FOS rearrangement in proliferative fasciitis/proliferative myositis

Proliferative fasciitis (PF) and proliferative myositis (PM) are rare benign soft tissue lesions, usually affecting the extremities of middle-aged or older adults. Presenting as poorly circumscribed masses, they histologically show bland spindle cell proliferation in a myxoid to fibrous background and a hallmark component of large epithelioid "ganglion-like" cells in various numbers, which may lead to their misdiagnosis as sarcoma. PF/PM has been long considered as reactive, akin to nodular fasciitis; however, its pathogenesis has remained unknown. In this study, we analyzed the FOS status in 6 PF/PMs (5 PFs and 1 PM). Five PF/PMs occurred in adults, all showing diffuse strong expression of c-FOS primarily in the epithelioid cells, whereas spindle cell components were largely negative. Using fluorescence in situ hybridization (FISH), all 5 c-FOS-immunopositive tumors showed evidence of FOS gene rearrangement in the epithelioid cells. RNA sequencing in 1 case detected a FOS-VIM fusion transcript, which was subsequently validated by reverse transcriptase-polymerase chain reaction, Sanger sequencing, and VIM FISH. The one pediatric PF case lacked c-FOS expression and FOS rearrangement. c-FOS immunohistochemistry was negative in 45 cases of selected mesenchymal tumor types with epithelioid components that may histologically mimic PF/PM, including pleomorphic sarcoma with epithelioid features and epithelioid sarcoma. Recurrent FOS rearrangement and c-FOS overexpression in PF/PM suggested these lesions to be neoplastic. FOS abnormality was largely restricted to the epithelioid cell population, clarifying the histological composition of at least 2 different cell types. c-FOS immunohistochemistry may serve as a useful adjunct to accurately distinguish PF/PM from mimics.

Patient Derived Xenografts for Genome-Driven Therapy of Osteosarcoma

Osteosarcoma (OS) is a rare malignant primary tumor of mesenchymal origin affecting bone. It is characterized by a complex genotype, mainly due to the high frequency of chromothripsis, which leads to multiple somatic copy number alterations and structural rearrangements. Any effort to design genome-driven therapies must therefore consider such high inter- and intra-tumor heterogeneity. Therefore, many laboratories and international networks are developing and sharing OS patient-derived xenografts (OS PDX) to broaden the availability of models that reproduce OS complex clinical heterogeneity. OS PDXs, and new cell lines derived from PDXs, faithfully preserve tumor heterogeneity, genetic, and epigenetic features and are thus valuable tools for predicting drug responses. Here, we review recent achievements concerning OS PDXs, summarizing the methods used to obtain ectopic and orthotopic xenografts and to fully characterize these models. The availability of OS PDXs across the many international PDX platforms and their possible use in PDX clinical trials are also described. We recommend the coupling of next-generation sequencing (NGS) data analysis with functional studies in OS PDXs, as well as the setup of OS PDX clinical trials and co-clinical trials, to enhance the predictive power of experimental evidence and to accelerate the clinical translation of effective genome-guided therapies for this aggressive disease.

Ossifying Plexiform Tumor: A Case Report

ABSTRACT

Ossifying plexiform tumor is an exceedingly rare cutaneous neoplasm with distinctive histologic features. The typical microscopic appearance is that of a well-circumscribed dermal lesion composed of spindled and epithelioid cells in a myxoid appearing matrix with a plexiform architecture associated with areas of ossification. The present report details the clinicopathologic features of an ossifying plexiform tumor involving the lower extremity of a 69-year-old man. The cutaneous lesion exhibited characteristic morphologic features of this entity. By immunohistochemistry, the tumor was negative for most markers assessed, but notably exhibited diffuse positivity for SATB2. No lesional recurrence was observed. The present case serves to expand on the limited existing knowledge regarding the clinicopathologic features of this uncommon tumor. The histogenesis of ossifying plexiform tumor remains unclear; however, the demonstration of SATB2 expression in this case suggests osteoblastic differentiation.

Immunohistochemical Characterization of Giant Cell Tumor of Bone Treated With Denosumab: Support for Osteoblastic Differentiation

Giant cell tumor of bone is a locally aggressive, rarely metastasizing neoplasm. Evidence suggests that the neoplastic cells may be osteoblastic in differentiation. Standard treatment is surgical removal, but medical therapy with denosumab, an inhibitor of receptor activator of nuclear factor-κβ ligand, has become a component of patient management in select cases. Denosumab-treated giant cell tumor of bone (DT-GCTB) shows drastic morphologic changes including the presence of abundant bone. To further determine the relationship of the neoplastic cells to osteoblast phenotype, we performed a morphologic and immunohistochemical study on a series of DT-GCTB. Cases of DT-GCTB were retrieved from surgical pathology files, available slides were reviewed, and immunohistochemistry for H3.3 G34W, SATB2, and p63 was performed. The cohort included 31 tumors from 30 patients (2:3 male:female), ages 15 to 73 years (median=36 y). The morphology of post-denosumab-treated tumors ranged from tumors composed of an abundant bone matrix with few spindle cells to spindle cell-predominant tumors. Five had focal residual classic CGTB, and 2 manifested mild nuclear atypia. The majority expressed all markers: 86.2% for H3.3 G34W, 96.7% for SATB2, and 100% for p63. All markers stained the various tumor components including spindle cells and the cells on the surface of and within the treated tumor bone matrix. Most markers were also positive in reactive-appearing woven bone adjacent to tumor: 84.6% for H3.3 G34W, 100% for SATB2, and 68% for p63. These findings suggest that denosumab treatment of giant cell tumor of bone results in osteoblastic differentiation with bone production.

Chondromyxoid Fibroma of the Temporal Bone: Case Report and Literature Review

Chondromyxoid fibroma (CMF) is a rare, benign, cartilaginous bone tumor that commonly affects the metaphysis of the lower-extremity long bones in young adults. Involvement of the craniofacial bones, especially the temporal bone, is exceedingly rare. We report a case of a 64-year-old man who presented with a left ear mass, but on subsequent imaging was found to have a more extensive mass centered in the temporal bone. Initial biopsy raised the concern for a low-grade chondrosarcoma. However, following surgical resection, a diagnosis of CMF was rendered. The clinical findings, radiographic features, histology, and differential diagnoses are discussed.

KPNA2 expression is a potential marker for differential diagnosis between osteosarcomas and other malignant bone tumor mimics

BACKGROUND

Karyopherin α2 (KPNA2), a member of the karyopherin α family, has been studied in several cancers but has not yet been substantially investigated in malignant bone tumors. The purpose of the current study was to evaluate the KPNA2 expression level and its utility as a novel diagnostic biomarker in osteosarcomas and malignant bone tumor mimics, such as chondrosarcomas and Ewing sarcomas (ESs).

METHOD

We investigated the expression of KPNA2 protein by immunohistochemistry on paraffin-embedded surgical specimens from 223 patients with malignant and benign bone tumors, including 81 osteosarcomas, 42 chondrosarcomas, 15 ESs, 28 osteoid osteomas, 20 osteochondromas and 37 chondroblastomas. Immunoreactivity was scored semiquantitatively based on staining extent and intensity.

RESULTS

Sixty-seven of 81 (82.7%) osteosarcoma, zero of 42 (0%) chondrosarcoma and one of 15 (6.7%) ES samples showed immunoreactivity for KPNA2. Negative KPNA2 expression was observed in all benign bone tumors. The expression of KPNA2 in osteosarcoma samples was much higher than that in chondrosarcoma and ES samples (P < 0.001). The sensitivity and specificity of KPNA2 immunoexpression for detecting osteosarcoma were 82.7 and 100%, respectively. Several subtypes of osteosarcoma were analyzed, and immunostaining of KPNA2 was frequent in osteoblastic samples (90.9%), with 39 samples (70.9%) showing strong-intensity staining. KPNA2 positivity was observed in ten of 13 (76.9%) chondroblastic, two of 6 (33.3%) fibroblastic, three of 4 (75%) telangiectatic and two of 3 (66.7%) giant cell-rich osteosarcoma samples. The strongest intensity staining was observed in osteoblastic osteosarcoma.

CONCLUSION

KPNA2 is frequently expressed in osteosarcomas, particularly in osteoblastic and chondroblastic tumors, but is rarely positive in chondrosarcomas and ESs. This feature may aid in distinguishing between osteosarcoma and other bone sarcoma mimics. This report supports KPNA2 as a novel marker for the diagnosis of osteosarcoma.

YJ5 as an immunohistochemical marker of osteogenic lineage

Overexpression of WLS, an upstream protein in the Wnt pathway, has been implicated in several non-osteogenic tumours. This study represents the first attempt at evaluating WLS expression in various bone and soft tissue tumours using YJ5, a monoclonal antibody specific to WLS, with the aim of elucidating its utility in discerning tumours with aberrant Wnt signalling and as a marker of osteogenic lineage in challenging cases. Tumour tissue sections of 144 bone mass lesions and 63 soft tissue mass lesions were immunostained with the YJ5 antibody following standardised protocols. Subsequent assessment of immunoreactivity segregated cases into one of three groups: absent/weak, moderate, or strong YJ5 immunoreactivity. For the bone tumours, strong YJ5 immunoreactivity was seen in almost all osteosarcomas and chondroblastomas, all osteoblastomas and osteoid osteomas. In contrast, all other cartilaginous tumours, chordomas, aneurysmal bone cysts, chondromyxoid fibromas, most fibrous dysplasias and most giant cell tumours exhibited absent/weak YJ5 immunostaining. For the soft tissue tumours, a more heterogeneous pattern of YJ5 immunoreactivity was observed. Because diffuse and strong YJ5 expression is identified in almost all benign and malignant bone tumours with osteoblastic activity, it can be potentially utilised as an immunohistochemical marker to support osteogenic lineage. If interpreted in the appropriate context, this marker is useful in determining whether a malignant bone tumour is an osteosarcoma, particularly in those subtypes with no or minimal osteoid or unusual morphological features. This marker can also complement SATB2 to denote osteogenic lineage.

SATB2 is not a reliable diagnostic marker for distinguishing between oral osteosarcoma and fibro-osseous lesions of the jaws

OBJECTIVE

Special AT-rich binding protein 2 (SATB2) is an immunohistochemical marker for osteoblast differentiation. Our aim was to investigate SATB2 expression in oral osteosarcoma and other bone-producing oral tumors/reactive lesions to evaluate its usefulness as a diagnostic marker.

STUDY DESIGN

A total of 74 intraosseous and soft tissue bone-producing surgical samples and 10 samples of reactive bone tissue were stained with SATB2, including osteosarcoma/chondrosarcoma (n = 16), fibro-osseous lesions (n = 42), central giant cell granuloma (n = 6), osteoblastoma (n = 1), and gingival lesions (n = 9). Nuclear labeling of the stromal spindle cells and intensity of staining was scored and analyzed.

RESULTS

The intraosseous (n = 65/65) and soft tissue samples (n = 9/9) diffusely expressed SATB2. The strongest expression was observed in juvenile aggressive ossifying fibroma (n = 2/2). Weak SATB2 expression was observed in the stromal spindle cells adjacent to reactive bone tissue (periosteal bone reaction).

CONCLUSIONS

Our results indicate that SATB2 is not a reliable diagnostic marker for oral osteosarcoma but has practical use in detecting cells with osteoblast differentiation in histologic samples with scant bone production or in differentiating between a periosteal bone reaction and neoplastic bone induced by the tumor mesenchymal cells. Targeting SATB2 as an alternative therapy in oral osteosarcoma, fibro-osseous lesions, and central giant cell granuloma should be further investigated.

SATB2: A versatile transcriptional regulator of craniofacial and skeleton development, neurogenesis and tumorigenesis, and its applications in regenerative medicine

SATB2 (special AT-rich sequence-binding protein 2) is a member of the special AT-rich binding protein family. As a transcription regulator, SATB2 mainly integrates higher-order chromatin organization. SATB2 expression appears to be tissue- and stage-specific, and is governed by several cellular signaling molecules and mediators. Expressed in branchial arches and osteoblast-lineage cells, SATB2 plays a significant role in craniofacial pattern and skeleton development. In addition to regulating osteogenic differentiation, SATB2 also displays versatile functions in neural development and cancer progression. As an osteoinductive factor, SATB2 holds great promise in improving bone regeneration toward bone defect repair. In this review, we have summarized our current understanding of the physiological and pathological functions of SATB2 in craniofacial and skeleton development, neurogenesis, tumorigenesis and regenerative medicine.

Metastatic colon cancer of the small intestine diagnosed using genetic analysis: a case report

BACKGROUND

Intestinal-type adenocarcinoma is widely detected in the gastrointestinal tract, head and neck, lower respiratory and urinary systems. Determining the nature (monoclonal or multicentric) of the intestinal adenocarcinoma is sometimes a diagnostic challenge owing to its occurrence at various locations of the body, especially in the lower gastrointestinal tract. Herein, we successfully diagnosed metastatic colon cancer in the small intestine using tumor protein 53 gene (TP53) mutation analysis.

CASE PRESENTATION

An 83-year-old woman presented with severe abdominal pain and nausea at the emergency department of the hospital. Her history included surgery and adjuvant chemotherapy for colon and breast cancers. Abdominal computed tomography revealed small intestinal dilation, which was associated with the mural nodule detected on fluorodeoxyglucose positron emission tomography. Laparoscopy-assisted small bowel resection was performed based on the diagnosis of small bowel obstruction, probably due to recurrence of the colon or breast cancer. Macroscopically, an ulcerated tumor was present in the resected small intestine. Histologically, the cancer cells showed infiltrative growth of colonic dysplastic glands, whose non-specific finding made it difficult to determine the relationship with past colon cancers. Retrospective pathological examination confirmed that the previous breast and colon carcinomas were primary cancers. Immunohistochemical analysis revealed that the small intestinal and colon cancer cells showed diffuse positive tumor protein 53 (p53) expression. However, the breast cancer cells showed only weakly positive p53 expression. In addition, TP53 mutational analysis detected an identical missense mutation (p.T211I) between the two intestinal cancers. Moreover, further molecular genetic work-up revealed that both small intestinal and colon adenocarcinomas harbored an identical missense mutation (p.G12D) of KRAS gene. In conclusion, the small intestinal cancer in this case was identified as a metastatic adenocarcinoma arising from a past colon cancer.

CONCLUSIONS

Genetic analyses help in clarifying the identity of the cells in multiple cancer cases. In morphologically indeterminate cases, molecular analysis of common cancer-related genes can be useful for a precise and reproducible diagnosis.

Retroperitoneal Sarcomas: An Update on the Diagnostic Pathology Approach

Retroperitoneal sarcomas are a heterogenous group of rare tumors arising in the retroperitoneum. Retroperitoneal sarcomas comprise approximately 10% of all soft tissue sarcomas. Though any soft tissue sarcoma histologic types may arise in the retroperitoneal space, liposarcoma (especially well-differentiated and dedifferentiated types) and leiomyosarcoma do so most commonly. Retroperitoneal sarcomas are diagnostically challenging, owing to their diversity and morphological overlap with other tumors arising in the retroperitoneum. An accurate diagnosis is necessary for correct management and prognostication. Herein, we provide an update on the diagnostic approach to retroperitoneal sarcomas and review their key histologic findings and differential diagnoses.

Dehydroandrographolide Inhibits Osteosarcoma Cell Growth and Metastasis by Targeting SATB2-mediated EMT

BACKGROUND

The 12-hydroxy-14-dehydroandrographolide (DP) is a predominant component of the traditional herbal medicine Andrographis paniculata (Burm. f.) Nees (Acanthaceae). Recent studies have shown that DP exhibits potent anti-cancer effects against oral and colon cancer cells.

OBJECTIVE

This investigation examined the potential effects of DP against osteosarcoma cell.

METHODS

A cell analyzer was used to measure cell viability. The cell growth and proliferation were performed by Flow cytometry and BrdU incorporation assay. The cell migration and invasion were determined by wound healing and transwell assay. The expression of EMT related proteins was examined by Western blot analysis.

RESULTS

In this study, we found that DP treatment repressed osteosarcoma (OS) cell growth in a dose-dependent manner. DP treatment significantly inhibited OS cell proliferation by arresting the cell cycle at G2/M phase. In addition, DP treatment effectively inhibited the migration and invasion abilities of OS cells through wound healing and Transwell tests. Mechanistic studies revealed that DP treatment effectively rescued the epithelialmesenchymal transition (EMT), while forced expression of SATB2 in OS cells markedly reversed the pharmacological effect of DP on EMT.

CONCLUSION

Our data demonstrated that DP repressed OS cell growth through inhibition of proliferation and cell cycle arrest; DP also inhibited metastatic capability of OS cells through a reversal of EMT by targeting SATB2. These findings demonstrate DP's potential as a therapeutic drug for OS treatment.

Effects of miR-103 by negatively regulating SATB2 on proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells

Background

The proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (HBMScs) are modulated by a variety of microRNAs (miRNAs). SATB homeobox 2 (SATB2) is a critical transcription factor that contributes to maintain the balance of bone metabolism. However, it remains unclear how the regulatory relationship between miR-103 and SATB2 on HBMScs proliferation and osteogenic differentiation.

Methods

HBMScs were obtained from Cyagen Biosciences and successful induced osteogenic differentiation. The proliferation abilities of HBMScs after treatment with agomiR-103 and antagomiR-103 were assessed using a cell counting Kit-8 (CCK-8) assay, and osteogenic differentiation was determined using alizarin red S staining and alkaline phosphatase (ALP) activity assay. The expression levels of miR-103, SATB2, and associated osteogenic differentiation biomarkers, including RUNX family transcription factor 2 (RUNX2), bone gamma-carboxyglutamate protein (BGLAP), and secreted phosphoprotein 1 (SPP1), were evaluated using real-time qPCR and Western blot. The regulatory sites of miR-103 on SATB2 were predicted using bioinformatics software and validated using a dual luciferase reporter assay. The underlying mechanism of miR-103 on SATB2-medicated HBMScs proliferation and osteogenic differentiation were confirmed by co-transfection of antagomiR-103 and SATB2 siRNA.

Results

The expression of miR-103 in HBMScs after induction of osteogenic differentiation was reduced in a time-dependent way. Overexpression of miR-103 by transfection of agomiR-103 suppressed HBMScs proliferation and osteogenic differentiation, while silencing of miR-103 by antagomiR-103 abolished these inhibitory effects. Consistently, RUNX2, BGLAP and SPP1 mRNA and protein expression were decreased in agomiR-103 treated HBMScs compared with those in agomiR-NC group. Meanwhile, antagomiR-103 upregulated the mRNA and protein expression levels of RUNX2, BGLAP and SPP1 in HBMScs. Further studies revealed that SATB2 was a direct target gene of miR-103. BMSCs transfected with agomiR-103 exhibited significantly downregulated protein expression level of SATB2, whereas knockdown of miR-103 promoted it. Additionally, rescue assays confirmed that silencing of SATB2 partially reversed the effects of antagomiR-103 induced HBMScs proliferation and osteogenic differentiation.

Conclusions

The present results suggested that miR-103 negatively regulates SATB2 to serve an inhibitory role in the proliferation and osteogenic differentiation of HBMScs, which sheds light upon a potential therapeutic target for treating bone-related diseases.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Fibroblastic Subtype has a Favourable Prognosis in Appendicular Osteosarcoma of Dogs

Osteosarcoma (OS) is an aggressive malignant bone neoplasm that occurs mostly in the appendicular skeleton of dogs and people. OS is classified based on the presence of malignant stroma and the formation of extracellular matrix into osteoblastic, chondroblastic and fibroblastic forms. This study investigated the correlation between the three histological subtypes of canine OS and clinical outcome. Additionally, we examined whether there was any difference in the immunolabelling of desmin, S100 and neuron-specific enolase (NSE) between the three histological subtypes. Formalin-fixed and paraffin wax-embedded tissues from 87 dogs with primary OS were available for this study. The survival times were correlated with appendicular OS subtypes in dogs that were treated surgically, received adjuvant chemotherapy and had no pulmonary metastasis at the time of diagnosis. Dogs with an appendicular fibroblastic OS had significantly prolonged mean average survival times (546 ± 105 days) in comparison with dogs having appendicular osteoblastic (257 ± 48 days) or appendicular chondroblastic (170 ± 28 days) OS (P = 0.003, Log Rank). The results also revealed that the appendicular chondroblastic subtype is a significant indicator for poor prognosis in dogs compared with the fibroblastic or osteoblastic subtypes (P = 0.006, Cox regression). Moreover, the findings indicated that there was no significant correlation between the localization of desmin, NSE or S100 and histological subtypes. Importantly, dogs with appendicular fibroblastic OS were found to have a better prognosis when compared with dogs with other subtypes. This may suggest that histological subtypes of appendicular OS have diverse behaviour and could be used to categorize patients for risk-based assessment.

SATB2 is frequently expressed in ossifying and non-ossifying peripheral oral fibroma of the gingival region but not in reactive fibromatous lesions from other intraoral sites

Ossifying and non-ossifying peripheral oral fibromas (POF) of the gingival and alveolar mucosa are localized, cellular, small fibrous nodular lesions likely resulting from diverse external/ internal physical and chemical irritation or injuries. A central nidus of metaplastic woven bone characterizes and defines the ossifying variant. The inherent tendency of these lesions to ossify remains elusive. We herein analyze SATB2 expression as osteoblastic transcription and differentiation factor in 28 gingival POFs (10 of them ossifying) and compare them to 28 fibrous lesions from different non-gingival intraoral sites. Strong to moderate diffuse nuclear SATB2 immunoreactivity was detected in all ossifying (10/10; 100%) and in 8/18 (44%) non-ossifying gingival POFs, but in only 1/28 (3%) non-gingival oral reactive nodular fibrous lesions. This study illustrates for the first-time consistent expression of the osteoblastic marker SATB2 in ossifying and most of non-ossifying POFs of the gingival area but lack of this marker in reactive fibrous lesions from other oral cavity sites. This finding is in line with the proposed origin of gingival POFs from periodontal ligaments and may explain the frequent ossification observed in them. It is mandatory to consider this finding when assessing biopsies from SATB2-positive oral cavity neoplasms to avoid misinterpretation.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

Clinical, histopathologic, subtype, and immunohistochemical analysis of jaw phosphaturic mesenchymal tumors

Jaw phosphaturic mesenchymal tumors (PMTs) are a rare neoplasm with uncertain histogenesis. This study aimed to clarify the clinical and pathological features of jaw PMTs.We reviewed the clinical records of 39 patients diagnosed with PMTs in the jaws, and investigated clinical and morphologic characteristics, histologic subtypes, and immunophenotypes of all cases.Microscopic analyses revealed 2 major histologic tumor subtypes: "phosphaturic mesenchymal tumors of mixed epithelial and connective tissue" (PMTMECT), and "phosphaturic mesenchymal tumors of mixed connective tissue" (PMTMCT). PMTMECTs and PMTMCTs accounted for 29 and 10 cases of PMTs, respectively. Most PMTMECT diagnoses were made predominantly in males aged <45 years, and the incidence was similar in both the mandible and maxilla. In contrast, patients with PMTMCTs are predominantly females aged ≥45 years, and all tumors were in the mandible. Histologically, PMTMECT had lower cellularity and a more elongated and spindled mesenchymal component with less elaborate intrinsic microvasculature than PMTMCT. Immunohistochemically, the epithelia of all PMTMECTs was immunoreactive for AE1/AE3. Other immunohistochemical staining of PMTMECTs revealed positive expression of vimentin, SATB2, ERG, CD99, Bcl-2, CD56, S-100, D2-40, CD68, SMA, and CD34 in either one or both components. Immunohistochemical staining of PMTMCTs was diffusely positive for vimentin and a varied ratio of positivity for SATB2, ERG, CD99, Bcl-2, CD56, S-100, D2-40, CD68, SMA, and CD34, but negative for AE1/AE3. Most patients were cured by complete resection, except 2 patients who had repeated recurrences, one of which also had multiple metastasis.Jaw PMT can be divided into 2 major histological subtypes. PMTMECTs are more common than are PMTMCTs, and can transform into malignant PMTMCTs during the progression. PMTMECTs were more commonly observed in males and the incidence was similar in both the maxilla and mandible. PMTMCTs were almost always observed in the mandible of females. Compared with PMTMCTs, PMTMECTs have an admixture of epithelial components with less prominent vasculature and lower cellularity. There were no statistically significant differences in the expression of immunohistochemical markers except AE1/AE3 between PMTMECTs and PMTMCTs. However, immunohistochemical markers have great significance for differentiating other mesenchymal tumors.