Protease expression in giant cell tumour of bone: a comparative study on feline and human samples

Immunohistochemical Characterization of Feline Giant Cell Tumor of Bone (GCTb): What We Know and What We Can Learn from the Human Counterpart

Giant cell tumor of bone (GCTb), formerly also known as osteoclastoma, is a pathological entity that in veterinary medicine is still undefined and, probably, underdiagnosed. In humans, GCTb is recognized as a primary benign bone tumor, locally aggressive, with high local recurrence rates, with controversial histogenesis that can rarely progress or present as a malignant form. In pets, this tumor is still considered rare, though the possibility of underdiagnosis is significant. Hence, the aim of the present study is to provide a histological and immunohistochemical characterization of a small case series of presumptive feline GCTb, comparing our results to the data reported for the human counterpart. Searching our archive, we found, from 2010 to 2023, only three diagnosed cases of GCTb from domestic cats (felis catus). After diagnosis revision, the samples were submitted to immunohistochemistry for Iba1, TRAP, SATB2, RUNX2, RANK, karyopherin α2 (KPNA-2), and osteocalcin. Ki-67 index was also evaluated. Results showed that the multinucleated giant cells were positive for Iba1, TRAP, and RANK, accounting for their osteoclastic origin. On the other side, mononuclear cells were mostly positive for osteoblast markers such as RUNX2, SATB2, and KPNA-2, whereas tumor-associated macrophages showed positivity for Iba1. Hence, results on the cell types characterizing the feline GCTb were comparable to those described in the human form of the tumor. Currently, diagnostic criteria for GCTBs in cats and, in domestic animals more broadly, are still lacking. This study provides valuable data into the immunohistochemical characteristics of the cell populations in feline GCTBs, enhancing veterinarians' and pathologists' knowledge for its diagnosis, ultimately improving patient care. Larger case series, complete with follow-up information, molecular analyses for specific mutations, and imaging of both tumors and patients, are needed to improve identification and achieve greater sensitivity in diagnosing this unique tumor.

Comparison of MMP-2, MMP-9, COX-2, and PGP Expression in Feline Injection-Site and Feline Noninjection-Site Sarcomas-Pilot Study

Feline injection-site sarcomas (FISSs) are aggressive neoplasms that have been associated mostly with vaccination. Feline noninjection-site sarcomas (non-FISSs) are less frequently observed in cats and may arise in any anatomic site. This study aimed to determine the differences in the expression of the selected proteins (matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), cyclooxygenase-2 (COX-2), and P-glycoprotein (PGP)) and their correlation with the mitotic count in FISS and non-FISS, in order to characterize their immunohistochemical features. A preliminary study of eleven samples of FISS and eight samples of non-FISS was performed using immunohistochemistry. Among all the tested sarcomas, 80.4% of the tumors were positive for COX-2, 90.2% were positive for MMP-9, and 100% were positive for PGP. The results showed that the expressions of COX-2, MMP-9, and PGP were significantly higher in FISS than in non-FISS (COX-2-p ≤ 0.001; MMP-9-p ≤ 0.05; and PGP-p ≤ 0.05). A Spearman rank correlation analysis showed a moderate negative correlation between the expression of COX-2 and MMP-9 in FISS (r = -0.52). A strong negative correlation between COX-2 and PGP (r = -0.81), a moderate positive correlation between MMP-2 and MMP-9 (r = +0.69), and a moderate negative correlation between MMP-2 and PGP (r = -0.44) were observed in non-FISS. In summary, our study presents the immunohistochemical profile of the proteins involved with inflammation and carcinogenesis in FISS and non-FISS, which can contribute to expanding the knowledge of tumor biology.

miR-106B-25 Cluster expression: a comparative human and canine osteosarcoma study

Background

Osteosarcoma (OS) is the most common primary malignant bone tumour in dogs and human beings, characterised by similar genetic and clinical features. With the aim to define similarities and differences in the biological aspects involved in OS progression, a comparative study was performed to create a model to improve patient outcome.

Methods

First, the expression of microRNAs (miRNAs) belonging to the cluster miR-106b-25 (miR-106b, miR-25 and miR-93-5p) in human and canine OS tissue was compared.

Results

miR-25 and miR-106b presented a variable expression not significantly different from the corresponding normal bone, while miR-93-5p expression was increased in all OS specimens, with higher levels in the canine subset compared with human. Accordingly, its target p21 presented a weaker and less homogeneous immunostaining distribution in the canine group. Given the high expression of miR-93-5p in all OS specimens, the functional response of human 143B and canine DAN OS cells to miRNA inhibition was evaluated. Although p21 expression increased after miR-93-5p inhibition both at mRNA and protein level, a more significant cell response in terms of proliferation and apoptosis was seen in canine OS cells.

Conclusions

In conclusion, canine OS tissue and cell line presented higher expression levels of miR-93-5p than human OS. In addition, the introduction of miR-93-5p inhibitor caused a cell response in 143B and DAN that differed for the more intense functional impact in the canine OS cell line.

An unusual case of giant cell tumor of soft parts in an American Warmblood horse

Fine needle aspiration and tissue biopsy samples were taken from a subcutaneous mass in the cranial stifle region of a 10-yr-old horse. Key cytologic features included numerous mildly to moderately pleomorphic histiocytic cells admixed with mononuclear inflammatory cells, occasional fibroblasts, multinucleated cells, and hemosiderin-laden macrophages. Based on these features, cytologic differentials included granulomatous inflammation with reactive fibroplasia, histiocytic sarcoma, giant cell tumor of soft parts (GCTSPs), and giant cell tumor of bone. The tissue biopsy supported a diagnosis of superficial GCTSPs. This neoplasm is of controversial origin but generally considered to be a soft tissue sarcoma and classified in the World Health Organization classification of tumors under fibrous histiocytic tumors as a giant cell tumor of soft tissue with low risk of malignancy. When found in the subcutis, this neoplasm rarely metastasizes in the horse and has a low rate of local reoccurrence. In this case, there was no local recurrence of the tumor after 6 mo, after which the horse was lost to follow-up.

Serum levels of urokinase-type plasminogen activator in healthy dogs and oncologic canine patients

AIM

Urokinase plasminogen activator (uPA) has been scarcely studied in veterinary oncology. The aim of this study was to determine the uPA serum concentrations in healthy and oncologic canine patients and to investigate its potential value as a tumor biomarker.

MATERIALS AND METHODS

Serum uPA concentrations of healthy and oncologic canine patients were measured by enzyme-linked immunosorbent assay. Their relationships with the dogs' health status and tumor characteristics were analyzed through ANOVA and independent t-test.

RESULTS

There were no significant differences between mean serum values (±standard deviation) of healthy dogs (0.19±0.13 ng/ml) and oncologic canine patients (0.22±0.33 ng/ml), or between dogs with benign or malignant tumors, and with or without metastases, although the latter tended to show higher uPA serum levels.

CONCLUSION

This is the first study describing the uPA serum levels in dogs. Although its results do not support uPA as a tumor biomarker, higher uPA levels in dogs with metastatic neoplasms may reflect the role of the enzyme in tumor progression.

Expression and activity of the urokinase plasminogen activator system in canine primary brain tumors

Background

The expression of the urokinase plasminogen activator receptor (uPAR), a glycosylphosphatidylinositol-anchored protein family member, and the activity of its ligand, urokinase-type plasminogen activator (uPA), have been associated with the invasive and metastatic potentials of a variety of human brain tumors through their regulation of extracellular matrix degradation. Domesticated dogs develop naturally occurring brain tumors that share many clinical, phenotypic, molecular, and genetic features with their human counterparts, which has prompted the use of the dogs with spontaneous brain tumors as models to expedite the translation of novel brain tumor therapeutics to humans. There is currently little known regarding the role of the uPA system in canine brain tumorigenesis. The objective of this study was to characterize the expression of uPAR and the activity of uPA in canine brain tumors as justification for the development of uPAR-targeted brain tumor therapeutics in dogs.

Methods

We investigated the expression of uPAR in 37 primary canine brain tumors using immunohistochemistry, Western blotting, real-time quantitative polymerase chain reaction analyses, and by the assay of the activity of uPA using casein–plasminogen zymography.

Results

Expression of uPAR was observed in multiple tumoral microenvironmental niches, including neoplastic cells, stroma, and the vasculature of canine brain tumors. Relative to normal brain tissues, uPAR protein and mRNA expression were significantly greater in canine meningiomas, gliomas, and choroid plexus tumors. Increased activity of uPA was documented in all tumor types.

Conclusions

uPAR is overexpressed and uPA activity increased in canine meningiomas, gliomas, and choroid plexus tumors. This study illustrates the potential of uPAR/uPA molecularly targeted approaches for canine brain tumor therapeutics and reinforces the translational significance of canines with spontaneous brain tumors as models for human disease.

Prognosis of local recurrence in giant cell tumour of bone: what can we do?

Giant cell tumour of bone (GCTB) is classified as an intermediate tumour with rare metastasis, but is challenged by local recurrence. This review focuses on the role of radiological evaluation in terms of prognosis of local recurrence in GCTB. We hope to highlight the value of radiological evaluation by integrating studies on the impact of surgical treatments and non-surgical factors on local recurrence of GCTB and the current statuses of genetic and molecular prognostic factors of GCTB. Radiological evaluation can provide diverse information on tumours. As a non-invasive method, magnetic resonance imaging (MRI) is especially valuable for the diagnosis and evaluation of bone tumours due to its heightened sensitivity to soft tissue disease and multiplanar image acquisition. Imaging findings should be integrated with clinical characteristics, pathology and genetic and molecular prognostic factors to direct clinical approach and reduce the local recurrence of GCTB. Therefore, it is necessary to establish a multi-perspective evaluation system by which prognostic factors can be reliably determined. We further advocate more large-scale prospective studies. With the help of radiological evaluation, the clinic treatment of GCTB can be guided and local recurrence might be reduced; additionally, MR imaging can identify local recurrence of GCTB after surgical treatment in the early stage.