A case-control study was carried out to determine whether residential exposure to environmental pollutants increased risk for canine lymphoma in pet dogs. One hundred one cases with cytologically or histologically confirmed lymphoma diagnosed at a veterinary teaching hospital between the middle of 1996 and the middle of 1998 were examined. Controls were obtained by choosing twice the number of dogs without neoplastic disease, with overlapping distributions of province of residence, age, sex, and breed. Information regarding animal management, residence type, professional or hobby use of chemicals by owners, and treatment with herbicides or other pesticides in the area frequently visited by the dogs was obtained with a multiple-choice questionnaire by telephone interview. Two variables were positively and independently associated with the disease, namely residency in industrial areas (odds ratio [OR]; = 8.5; 95% confidence interval [CI], 2.3-30.9) and use of chemicals by owners, specifically paints or solvents (OR = 4.6; 95% CI, 1.7-12.6). A significantly lower value of the mean age of disease onset was found in the group of dogs at risk in comparison with the group of all other dogs (6.1 +/- 0.4 years, n = 36 versus 7.5 +/- 0.4 years, n = 65, respectively; P = .008). Variables describing animal care and pesticide use were either not associated with the disease or were uninformative. We suggest that canine lymphoma may be considered a sentinel of potentially hazardous situations for humans, because of the relatively short latency between exposure and disease onset.

Malignant lymphoma B-cell type is the most common canine haematopoietic malignancy. Changes in intestinal microbiota have been implicated in few types of cancer in humans. The aim of this prospective and case-control study was to determine differences in faecal microbiota between healthy control dogs and dogs with multicentric lymphoma. Twelve dogs affected by multicentric, B-cell, stage III-IV lymphoma, and 21 healthy dogs were enrolled in the study. For each dog, faecal samples were analysed by Illumina sequencing of 16S rRNA genes and quantitative PCR (qPCR) for selected bacterial groups. Alpha diversity was significant lower in lymphoma dogs. Principal coordinate analysis plots showed different microbial clustering (P = .001) and linear discriminant analysis effect size revealed 28 differentially abundant bacterial groups in lymphoma and control dogs. The qPCR analysis showed significant lower abundance of Faecalibacterium spp. (q < .001), Fusobacterium spp. (q = .032), and Turicibacter spp. (q = .043) in dogs with lymphoma compared with control dogs. On the contrary, Streptococcus spp. was significantly higher in dogs with lymphoma (q = .041). The dysbiosis index was significantly higher (P < .0001) in dogs with lymphoma. In conclusion, both sequencing and qPCR analyses provided a global overview of faecal microbial communities and showed significant differences in the microbial communities of dogs presenting with multicentric lymphoma compared with healthy control dogs.

Canine cancers occur with an incidence similar to that of humans and share many features with human malignancies including histological appearance, tumor genetics, biological behavior, and response to conventional therapies. As observed in humans, the telomerase reverse transcriptase (TERT) activity is largely confined to tumor tissues and absent in the majority of normal dog tissues. Therefore, dog TERT (dTERT) can constitute a valid target for translational cancer immunotherapy. We have evaluated the ability of adenovirus serotype 6 (Ad6) and DNA electroporation (DNA-EP) to induce immune responses against dTERT in dogs affected by malignant lymphoma (ML). The vaccine was combined with standard chemotherapy regimen [cyclophosphamide, vincristine, prednisone (COP)]. dTERT-specific immune response was induced in 13 out of 14 treated animals (93%) and remained detectable and long-lasting with the absence of autoimmunity or other side effects. Most interestingly, the survival time of vaccine/Chemo-treated dogs was significantly increased over historic controls of Chemo-treated animals (>97.8 versus 37 weeks, respectively, P = 0.001). Our results show that Ad6/DNA-EP-based cancer vaccine against dTERT overcomes host immune tolerance, should be combined with chemotherapy, induces long-lasting immune responses, and significantly prolongs the survival of ML canine patients. These data support further evaluation of this approach in human clinical trials.

To describe the results of electrochemotherapy (ECT) in dogs with mast cell tumours (MCTs) either as first line therapy or as an adjuvant to surgery. The treatment combines administration of low dose chemotherapeutic drugs with the application of microsecond electric pulses, which cause the temporary permeabilization and increased porosity of the tumour cell membranes. The design of this study is a retrospective case series. A total of 51 dogs with MCTs were included and classified according to ECT procedure into 4 groups (ECT only, 15 cases, intra-surgery ECT, 11, ECT Adjuvant to surgery, 14, Surgery followed by ECT, 11). The four groups (staged with location, size and grade) were evaluated to assess complete or partial remission, disease free interval, overall survival time and local toxicity. In this case series, Boxers, mixed breed and Labrador Retrievers, male dogs, between 4 and 9 years old were more represented. MCTs were predominantly grade 2 (Patnaik) and T stage 0-1, I-1 (World Health Organization). Treated lesions were most commonly identified on the hindlimb and head where curative surgery would involve cosmetic or functional compromise. The intra-surgery group of dogs showed the best disease free interval with Kaplan-Meyer analysis. Local toxicity induced by ECT ranged mostly from 1 to 4 in a 5-point arbitrary scale with 0 - no toxicity to 5 - highest toxicity. In this study, ECT can be applied successfully as an exclusive therapy in smaller MCTs as an alternative to surgery. ECT can be combined with surgery either intra-operatively or post operatively for larger lesions without significant toxicity.