Takashi Mori

Background: Prognostic factors in dogs with nasal tumors include several variables. However, factors that can measure prognosis have not yet been identified due to considerable divergence among reports. Aim: To describe the computed tomography (CT) imaging, treatment, and outcomes of dogs with nasal tumors, as well as detect negative prognostic factors through the analysis of a substantial number of cases from a single institution. Furthermore, based on CT findings, this study aimed to identify independent prognostic factors for nasal tumors in dogs. Methods: A total of 166 client-owned dogs were diagnosed with nasal tumors at Gifu University Veterinary Hospital between 2015 and 2019. Data were retrospectively collected from the electronic medical records. Results: Univariate analysis revealed a significant difference in survival time between adenocarcinoma and squamous cell carcinoma in 166 canine nasal tumors treated with megavoltage radiation therapy at a single institution (p= .015). There was a significant difference in survival time between carcinoma and sarcoma (p= .04). Regarding CT imaging findings, significant differences in survival time were observed for frontal sinus invasion (p= .007), cribriform plate destruction (p< .001), and lymph node metastasis (p= .003). Multivariate Cox regression analysis was performed to assess frontal sinus invasion, cribriform plate destruction, histopathologic subtypes, and lymph node metastasis as negative prognostic factors; however, only cribriform plate destruction was a significant negative prognostic factor for survival time (p= .004). Conclusion: Multivariate Cox regression analysis showed that cribriform plate destruction was the main factor in predicting a negative prognosis among 166 canine nasal tumors treated with megavoltage radiation therapy at a single institution. Therefore, we propose a new 2-tier staging classification for canine nasal tumors with the presence or absence of cribriform plate destruction based on CT examination as the only evaluation factor.

Background: Canine hemangiosarcoma (HSA), which originates from endothelial cells, is one of the most common malignant neoplasms that frequently develop metastatic lesions. Although anthracycline-based HSA treatment strategies have been widely investigated, reliable therapy for dogs with clinically advanced-stage HSA (stage 3 HSA) has not been established yet. Recently, several studies have demonstrated that propranolol, a beta-adrenergic receptor antagonist, exhibits anti-tumor effects against tumors originating from vascular endothelial cells, indicating the possibility that propranolol is a candidate adjunctive agent for anthracycline-based therapy in dogs with stage 3 HSA. This study aimed to evaluate the clinically efficacy and adverse events of anthracycline and propranolol combination in stage 3 HSA-affected dogs. Case Description: We retrospectively investigated 5 dogs diagnosed with stage 3 HSA which were administered with both anthracycline and propranolol during the same period between January 2020 and August 2021. Clinical benefit was observed in 4 of 5 HSA dogs (1 of complete response [CR], 1 of partial response [PR] and 2 of stable disease [SD]) with gross metastatic lesions by anthracycline and propranolol combination. Notably, some or all of the metastatic lesions were reduced in 2 cases. In all 5 dogs administered with anthracycline and propranolol combination, no serious and irreversible adverse effects were observed. Conclusion: Our findings demonstrate the efficacy and safety of anthracycline and propranolol combination in stage 3 HSA-affected dogs. Further studies are needed to establish treatment protocols based on anthracycline and propranolol combination for dogs with advanced HSA.

Despite considering hypofractionated radiotherapy (HRT) a useful treatment option for feline localized sinonasal lymphoma (stage I), the benefits of additional chemotherapy remain controversial. This retrospective cohort study evaluated the efficacy of the early initiation of chemotherapy in combination with HRT (HRTC) to prolong the progression-free survival (PFS) and overall survival (OS) in cats with localized sinonasal lymphoma compared with HRT alone. While 24 eligible cats received HRT alone (HRT group), 18 received HRTC (HRTC group). The total median administered dose was 35 Gy, with one fraction per week, for a median of five fractions. In the HRTC group, the chemotherapy protocol was cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-based and cyclophosphamide, vincristine, and prednisolone (COP)-based in 14 (78%) and 4 cats (22%), respectively. Cats in the HRTC group had significantly longer PFS (677 versus 104 days; P = .04) and OS (983 versus 263 days; P = .04) than those in the HRT group. Considering the poor outcome in the HRT group despite the cats having received rescue chemotherapy for progressive disease, the early initiation of additional chemotherapy along with HRT may be recommended for feline localized sinonasal lymphoma.

The prognosis for bile duct carcinoma in dogs is generally believed to be poor. However, only a few studies have evaluated the postoperative outcomes in such cases. The objective of this case series was to describe the postoperative outcomes of localized intrahepatic bile duct carcinoma in dogs. The electronic medical records of 16 dogs with bile duct carcinoma were reviewed, and 6 dogs were included in the study. All cases were diagnosed as bile duct carcinoma using postoperative pathology, and five of them had already been diagnosed using preoperative core biopsy. The tumors in all of the dogs were confirmed as completely resected on histopathological examination. Two dogs received toceranib following the surgery. The median follow-up time was 693 days (range, 420–1386 days), with a median survival time of 894 days (range, 420–1386 days). Local recurrence or distant metastases were detected in two of the six dogs (33%) on 354 and 398 days following surgery, respectively. The median progression-free survival was 492 days (range, 354–1386 days). In conclusion, dogs with localized intrahepatic bile duct carcinoma had a good prognosis following complete surgical resection.

Molecular subtyping in gastrointestinal stromal tumours is a useful method for predicting the efficacy of treatment using tyrosine kinase inhibitors in humans. However, owing to the paucity of reports on mutational analyses, the association between genetic mutations and the therapeutic response to tyrosine kinase inhibitors remains unclear in feline gastrointestinal stromal tumours. In this report, we describe the case of a cat with a gastrointestinal stromal tumour which was unresponsive to tyrosine kinase inhibitors. A mutational analysis revealed that the cat lacked mutations in both the KIT and platelet-derived growth factor receptor-alpha (PDGFRA) genes. Our findings are consistent with the fact that KIT/PDGFRA wild-type gastrointestinal stromal tumours are less responsive to tyrosine kinase inhibitors in humans. This signifies the need for further evaluation and possibly individualised treatment for gastrointestinal stromal tumours in cats on the basis of mutational analyses.

Objective: To determine the feasibility of three‐dimensional conformal radiation therapy for canine aortic body tumours.Materials and Methods: Medical records of dogs that had undergone three‐dimensional conformal radiation therapy with presumptive diagnosis of aortic body tumour were reviewed for clinical characteristics, treatment modality and outcomes.Results: Eight dogs were diagnosed with aortic body tumour and were treated with three‐dimensional conformal radiation therapy. One dog had proliferation of a mass in the right atrium during treatment and died of respiratory distress. Another dog did not undergo follow‐up CT to evaluate the treatment response due to the increased blood urea nitrogen values. The remaining 6 dogs were included in the case series. Radiotherapy was performed using a median dose per fraction of 7 Gy (3.3‐7.14 Gy), a median of seven divided doses (7‐15) and a total median dose of 49 Gy (45‐50 Gy). The median number of CT scans during the follow‐up period was 5 (range: 3‐8 times). CT revealed acute side effects in four dogs—grade 1 effects related to the lung (n = 4) and skin (n = 2). Self‐limiting or asymptomatic late side effects (grade 1 lung‐related effect) were observed in three dogs. After therapy, one dog demonstrated a complete response, another demonstrated a partial response and the disease remained stable in four animals. The median follow‐up period was 514.5 (235‐1219) days. After three‐dimensional conformal radiation therapy, the aortic body tumour reduced gradually over time without regrowth in all these 6 dogs.Clinical Significance: In this small case series, aortic body tumours responded to three‐dimensional conformal radiation therapy. Transient and self‐limiting side effects of the treatments were common. Further controlled studies are required to prove the effectiveness and the safety of this intervention.

MicroRNA‐214 (miR‐214), a pivotal tumour‐suppressive miRNA, is downregulated in canine hemangiosarcoma (HSA) cells. Although these tumour‐suppressive miRNAs are potential therapeutic agents, their clinical efficacy may be limited because of their vulnerability to RNase‐rich microenvironments and low in vivo transfection rates. We developed synthetic miR‐214 s with enhanced cytotoxicity, RNase resistance, and quantity of miR‐214 in/on cells. These synthetic miR‐214 s were synthesized by various chemical modifications (such as 4′‐aminoethyl‐2′‐fluoro, 2′‐fluoro, 2′‐O‐methyl, phosphorothioate, and oligospermine modifications) of the wild‐type mature miR‐214 sequences. Transfection of HSA cells with synthetic miR‐214 (miR‐214 5AE) demonstrated significant growth suppressive effect and induced the strongest apoptotic response. Synthetic miR‐214 s (miR‐214 5AE, miR‐214 10AE, and miR‐214 OS) were much more stable than mature miR‐214 s in foetal bovine serum. Similar to mature miR‐214, 5AE and OS suppressed the expression level of COP1 in HSA cells. The quantity of synthetic miR‐214 s in/on cells was higher than that of mature miR‐214. In conclusion, we developed a clinically applicable, synthetic miR‐214 5AE that regulates the COP1 protein expression similar to that mediated by mature miR‐214. Additionally, miR‐214 5AE confers better cytotoxicity, nuclease resistance, and transfection rate than mature miR‐214. Thus, miR‐214 5AE could potentially be a novel miRNA‐based chemotherapeutic agent that could improve the prognosis of HSA. Its in vivo effects on canine HSA has need to be examined in future.

Canine oral malignant melanoma (CoMM) is often treated by radiation therapy in veterinary medicine. However, not all cases are successfully managed by this treatment. For improved efficacy of radiation therapy, biomarkers predicting the radiosensitivity of melanoma cells need to be explored. Here, we, first, developed the radioresistant CoMM cell line, KMeC/R. We found that the expression level of phosphatase and tensin homolog (PTEN) of KMeC/R cells was significantly downregulated compared with KMeC cells. Overexpression of PTEN successfully restored the radiosensitivity of KMeC/R cells, and silencing of PTEN significantly increased the radioresistance of the CoMM cells tested. Next, we focused on microRNAs (miRNAs) to explore the mechanisms of downregulation of PTEN in KMeC/R cells. miR-374b was upregulated in KMeC/R cells compared with that in KMeC cells and in the irradiated CoMM cells tested. Furthermore, miR-374b directly targeted PTEN based on the luciferase activity assay. Moreover, the extrinsic miR-374b significantly increased the radioresistance of KMeC cells. In addition, the expression level of PTEN was significantly downregulated and that of miR-374b tended to be upregulated in recurrent CoMM tissues after radiation therapy compared with the pre-treatment tissues. Thus, the current study suggested that the miR-374b/PTEN signaling pathway possibly plays an important role in CoMM radiosensitivity.

Metaphase chromosome analysis of lymphocytes is the gold standard for biodosimetry to estimate the levels of radiation exposure in various animals as well as humans. Animals, including experimental, companion, and wild animals, are powerful and indispensable models for researching radiation injury, safety, and therapy. Moreover, biodosimetry of animal models can be used to support human biodosimetry data and may be useful for estimating environmental contamination by radioactive materials. The basic restraint procedure and venipuncture technique are different depending on each animal type. The general procedure evaluating metaphase chromosomes is similar to the human blood technique except for a minor modification in the initial culture. This chapter will introduce basic mouse, rat, rabbit, dog, cat, cow, horse, goat, pig, and wild boar venipuncture and blood sampling techniques for metaphase chromosome preparation and analysis.

Dogs with appendicular osteosarcoma (OSA) receiving standard amputation and adjuvant chemotherapy demonstrate variable outcome with treatment; however, additional biomarkers would be helpful for predicting their outcome. In the present study, we assessed the potential of circulating microRNA-214 (miR-214) and − 126 (miR-126) to predict time to metastasis and death in dogs with OSA treated with amputation and chemotherapy. Seventy-six dogs that fully met inclusion criteria were included in the analysis. The criteria included (1) a diagnosis of appendicular OSA without metastases at diagnosis, (2) treatment by amputation and chemotherapy using carboplatin, doxorubicin, cisplatin, or a combination of these agents. Circulating miR-214 and -126 levels at the time before treatment were measured by using RT-qPCR. High circulating miR-214 and serum alkaline phosphatase (ALP) significantly predicted short disease-free survival (DFS) and overall survival (OS). Conversely, high circulating miR-126 significantly predicted prolonged DFS and OS. An integrated approach using circulating miR-214, − 126, and serum ALP showed better accuracy in the prediction of DFS and OS and identification of long-term survivors than prediction using only ALP. Other variables (age, weight, sex, monocyte counts, and primary tumor site) were associated with neither DFS nor OS. miRNA levels did not strongly correlate with histopathological indices. Circulating miR-214, − 126, and an integrated prognostic score have strong potential to predict the outcome of canine appendicular OSA patients receiving amputation and chemotherapy.