Veterinary and comparative oncology最新文献

This multicenter retrospective study evaluated the effects of a time delay and steroids on the volume of peritumoral edema (VPTE) in dogs with extra-axial brain tumours. The hypothesis is that VPTE will decrease between the diagnostic (MRI-1) and RT planning (MRI-2) MRIs following the administration of steroids. Inclusion required paired MRI acquisitions within 3 months, with VPTE contouring for each MRI registered to the RT planning CT. No edema was defined as < 0.2 cm³, increased edema was > 30% VPTE increase and decreased edema was > 30% VPTE decrease. Forty-four dogs of which 34 (77%) received steroids between MRIs were included. The median time between the MRIs was 22 days (range: 8-74 days). Nine (20%) had no edema on both MRIs. The median MRI-1/VPTE: 0.83 cm³ (IQR: 0.15-2.06 cm³) and median MRI-2/VPTE: 0.40 cm³ (IQR: 0.06-1.12 cm³) were significantly different (p = 0.048). Compared to MRI-1/VPTE: 17 (39%) VPTE decreased, eight were stable and 10 increased. The median VPTE difference was -21%, range: -100 to +6287. With steroids, VPTE decreased in 15/34 (44%) and increasedin 6/34 (18%) (median VPTE diff: -60%) compared to no steroids (median VPTE diff: +25%). Steroids use was associated with change in VPTE (p = 0.009). Two dogs had clinical deterioration and were on steroids with documented VPTE increase (+86% and +1880%) without tumour progression. The change in VPTE is highly variable but reduction is associated with steroids. Notably, subjective improvement of clinical signs can be seen without significant decrease to the VPTE on imaging.

Pre-metastatic niche (PMN) formation is essential for metastatic development and drives organotropism. Tumour-derived extracellular vesicles and soluble factors remodel the microenvironment of distant metastatic organs before subsequent metastasis. Dogs with osteosarcoma (OS) have proven to be excellent disease models for their human companions. Here, we show evidence of PMN formation in dogs with OS before metastasis. We necropsied and sampled lung tissues from dogs with naturally occurring treatment-naïve OS (n = 15) and control dogs without cancer (n = 10). We further divided dogs with OS into those having lung metastases (n = 5) and those without (n = 10). We stained formalin-fixed paraffin-embedded tissues using multiplex immunofluorescence to quantify the number of bone marrow-derived cells, monocytes and macrophages in the lung samples from each dog. The numbers of CD204⁺ macrophages, CD206⁺ macrophages and monocytes and CD11d⁺ bone marrow-derived cells (BMDCs) were significantly higher in the pre-metastatic lung of dogs with OS (n = 10) than in control dogs without cancer (n = 10). Furthermore, the total nucleated cell (DAPI⁺) density was higher before metastasis than in healthy lungs. In dogs with established metastases, the number of CD11d⁺ BMDCs was significantly lower than in the pre-metastatic lung, suggesting this recruitment is transient. Our study provides evidence of PMN existence in a naturally occurring cancer model similar to those observed in pre-clinical murine models. BMDCs are recruited to the lungs before metastases have developed. Dogs with OS may represent ideal candidates for assessing new PMN-targeting therapies.

Canine mast cell tumours (MCTs) are one of the most common skin cancers of dogs. Surgical removal is the primary treatment, but recurrence and metastasis can occur even with low-grade tumours. As a result, new treatment strategies are being sought. We tested the potential of several oncolytic viruses (OVs) to infect and kill a cell line isolated from a canine MCT. Employing a resazurin-based metabolic assay and flow cytometry technology, we used recombinant vesicular stomatitis virus (rVSV-Δm51), avian orthoavulavirus-1 (AOaV-1), and Orf viruses in our assessment. Our study aimed to evaluate the potential of oncolytic virotherapy in treating canine cancers. We found that MCT-1 cells showed different sensitivities to the OVs, with rVSV-Δm51 showing the most promising results in vitro. These findings suggest that further investigation into using OVs for treating canine MCTs is needed, although clinical efficacy is yet to be determined.

Carotid body paragangliomas represent an uncommon neoplasm in dogs. The objective of this study was to report outcomes and complications associated with surgical excision of carotid body paragangliomas in 21 dogs. Cases were recruited retrospectively via medical record review from 9 veterinary speciality centres. The perioperative complication rate was 52% (11/21). Complications encountered in this cohort related to removal of carotid body tumour included airway obstruction, aspiration pneumonia, megaesophagus, unilateral laryngeal paralysis, coughing and Horner's syndrome. The overall perioperative mortality rate was 4.7% (1/21 dogs) and median survival time was 554 days for the six patients with known dates of death. One- and two-year survival rates were 61% and 42%, respectively. This is the largest collection of carotid body paraganglioma cases reported in veterinary literature. Based on these results, surgical resection of carotid body paragangliomas was associated with low perioperative mortality and long survival times.

Data regarding the outcome of canine rib chondrosarcoma is sparse and varied. While grade of tumour is associated with outcome for canine appendicular chondrosarcoma, the association of grade with outcome for canine rib chondrosarcoma is unclear. This study aimed to correlate the grade of canine rib chondrosarcoma with median survival time. Retrospectively, cases of primary rib chondrosarcoma were identified, and tumours were graded based on a 3-tier adapted human grading scheme. Twenty-two patients were included in the survival analysis. The median survival time was 1427 days (range: 27-3354 days). This was not significantly different for patients with grade I versus II versus III (p = 0.82), grade I-II versus III (p = 0.34), or grade I versus II-III (p = 0.49). No variables assessed including age, weight, tumour location (cranial vs. caudal thorax; left vs. right hemithorax), tumour location on rib (proximal, middle, and distal), radiographic appearance (lytic, proliferative, or mixed), elevated serum alkaline phosphatase activity, grade, grade specific histologic features (matrix production, architecture, pleomorphism, cellularity, necrosis, and total score), adjunct therapy post-surgical excision, development of metastatic disease post-surgery, or local recurrence post-surgery were found to impact the risk of death due to chondrosarcoma. In this limited group of patients, the grading scheme reported here, and the other variables assessed did not appear to offer additional prognostic information. However, this data must be interpreted considering the small sample size and thus low statistical power. Additional studies are needed to determine the true impact of grade on outcome for canine rib chondrosarcomas.

CCNU (1-[2-chloroethyl]-3-cyclohexyl-1-nitrosurea), lomustine, is an oral alkylating agent in the nitrosourea subgroup. The dose-limiting toxicity of CCNU is neutropenia most frequently documented 7 days after its administration. Use of prophylactic antimicrobials to prevent chemotherapy-related febrile neutropenia (FN) and its associated morbidity and mortality has been well-documented in human oncology, but this information is limited in the veterinary literature. The purpose of this multi-institutional retrospective study was to assess whether antimicrobial prophylaxis reduced the risk of FN approximately 7 days after CCNU administration in tumour-bearing dogs. A secondary goal was to identify risk factors for fever development in neutropenic dogs. Two hundred dogs were included in the study. One hundred and fifty-three dogs (76.5%) were neutropenic at the first post-CCNU recheck. One hundred and six (69.3%) dogs received prophylactic antimicrobials and 47 (30.7%) did not. Of the 106 dogs on prophylactic antimicrobials, 8 (7.5%) developed FN. Of the 47 dogs in the no-prophylactic antimicrobials group, 4 (8.5%) developed FN. Use of prophylactic antimicrobials did not reduce the risk of development of FN (p = 0.84). Older age (> 9 y), lower weight and body surface area, and pre-treatment with chemotherapy or radiation therapy were significantly associated with development of FN (p = 0.009, p = 0.023, p = 0.015 and p = 0.01). Patients with a lower absolute neutrophil count, and a higher VCOG-CTCAE v2 neutropenia grade were also at an increased risk of developing FN (p = 0.01, p < 0.001). Additional studies may help establish guidelines for antimicrobial prophylaxis in dogs treated with CCNU, especially for those at high-risk for FN.

Canine cutaneous/subcutaneous soft-tissue sarcomas (STS) are diversely derived mesenchymal neoplasms with a risk of recurrence and/or metastasis depending on the extent of surgical excision and histologic grade. Lymphoid aggregates (LAs) are often described in these tumours but not characterised. In humans, LA characterised as tertiary lymphoid structures (TLSs) improve the prognosis of many tumours, including sarcomas. We sought to determine if LA meeting a size criterion (> 700 cells) in canine sarcomas met the criteria of TLS and the overall prevalence of LA of any size. RNA expression in large LAs versus aggregate-adjacent sarcoma tissue (AAS) was measured in laser capture microdissected tissue and compared to curl-derived RNA from aggregate-free sarcomas and lymph nodes. CD3, CD20, MUM-1 and PNAd expressions were measured using immunohistochemistry. CD20 and CD3 mRNA were more highly expressed in LA versus AAS (13.8 fold, p = 0.0003 and 2.3 fold, p = 0.043). This was supported by the IHC findings. The large LAs were also enriched in chemokine RNA expression characteristic of TLS (CXCR5 5.8 fold, p < 00001, CCL19 3.68 fold, p = 0.0209, CCL21 6.87 fold, p = 0.0209 and CXCL13 2.68 fold, p = 0.0924). Plasma cells and high endothelial venules were identified in LA containing tumours but not in control tissue. Large LAs were present in 12% of tumours, and LA of any size in 30%. We conclude that large LAs in canine STS are consistent with TLS.

Nodal metastasis is a negative prognostic factor in dogs with mast cell tumours (MCTs), thus early detection enables more informed decision-making and provides valuable prognostic information. The aim of this study is to assess the concordance between histopathologic findings of LNs and cytology and flow cytometry (FC), respectively, and to evaluate the ability of FC to differentiate between metastatic (HN2-HN3) and non-metastatic (HN0-HN1) LNs. Overall, 117 LNs from 64 dogs with first occurring MCTs were submitted for cytology, histology and FC. LNs were cytologically and histologically classified according to Krick and Weishaar systems, respectively. Using FC, mast cells (MCs) were identified as IgE+ CD117+ CD5- CD21- cells and quantified as a percentage. When compared with histologic classification, cytology showed an accuracy of 88.2% in distinguishing between metastatic and non-metastatic LNs but did not detect 25.3% of metastatic cases. FC revealed an increase in the median percentages of MCs across histologic classes, progressing from HN0 to HN3. ROC curves pinpointed 0.3% as the optimal cut-off for distinguishing between metastatic and non-metastatic LNs, with an accuracy of 84.3%. A 1.1% cut-off proved valuable in identifying HN3 LNs. The combined interpretation of cytology and FC increased accuracy to 92.2%. An algorithm for guiding the combined interpretation of cytology and FC is suggested based on these findings. In conclusion, FC proves beneficial in enhancing the early detection of metastatic LNs, particularly when utilised alongside cytology. Histopathology remains essential for confirmation, enabling the discrimination of HN classes or, in doubtful cases, for the detection or exclusion of nodal metastases.

Canine mucosal melanoma (CMM) is the most common oral malignancy in dogs and is significantly more aggressive than its cutaneous counterpart (CCM), yet the reasons for this disparity remain unclear. Cancer-associated stroma (CAS) plays a crucial role in tumour progression, but a detailed understanding of CAS in canine melanoma is missing. To assess stromal reprogramming, we analysed CAS from 21 CMM, 14 CCM and normal stroma from 10 skin and 9 oral mucosa samples by laser-capture microdissection followed by RNA sequencing. Results were assessed in relation to subtypes, prognostic factors including mitotic count (MC), ulceration, necrosis, pigmentation and immune cell infiltration (CD3, CD20 and CD68), scored using immunohistochemistry and RNA in situ hybridisation. Stromal reprogramming was evident in both subtypes but significantly more pronounced in CMM. Immune-excluded tumours exhibited higher MC than desert/cold ones. MC strongly correlated with genes associated with B-cells, T-helper cells and CTLA4 in CCM, suggesting CAS reprogramming to depend on tumour malignancy. Finally, we identify an immune-suppressive stromal signature in a subset of CMM characterised by the downregulation of key immune checkpoints and pathways. Together, these findings provide a solid foundation for understanding the role of CAS in canine melanoma, specific to cutaneous and mucosal subtypes.

BRAF is one of multiple RAF proteins responsible for the activation of the MAPK cell signalling cascade involved in cell growth, differentiation, and survival. A hotspot BRAF^V600E mutation, in exon 15, was determined to be a driver in 100% hairy cell leukaemias, 50%-60% of human melanomas, 30%-50% of human thyroid carcinomas and 10%-20% of human colorectal carcinomas. The orthologous BRAF^V595E mutation was seen in 67% and 80% of canine bladder transitional cell carcinomas and prostatic adenocarcinomas, respectively. Since veterinary and human cancers exploit similar pathways and BRAF is highly conserved across species, BRAF can be expected to be a driver in a feline cancer. Primers were developed to amplify exon 15 of feline BRAF. One hundred ninety-six feline tumours were analysed. Sanger sequencing of the 211 bp PCR amplicon was done. A BRAF mutation was found in one tumour, a cutaneous melanoma. The mutation was a BRAF^V597E mutation, orthologous to the canine and human hotspot mutations. A common synonymous variant, BRAF^T586T, was seen in 23% (47/196) of tumours. This variant was suspected to be a single nucleotide polymorphism. BRAF was not frequently mutated in common feline tumours or in tumour types that frequently harbour BRAF mutations in human and canine cancers. As is seen in canine cancer genomics, the mutational profile in feline tumours may not parallel the histologic equivalent in human oncology.