From Conventional to Precision Therapy in Canine Mammary Cancer: A Comprehensive Review.

Canine mammary tumors (CMTs) are the most common neoplasm in intact female dogs. Canine mammary cancer (CMC) represents 50% of CMTs, and besides surgery, which is the elective treatment, additional targeted and non-targeted therapies could offer benefits in terms of survival to these patients. Also, CMC is considered a good spontaneous intermediate animal model for the research of human breast cancer (HBC), and therefore, the study of new treatments for CMC is a promising field in comparative oncology. Dogs with CMC have a comparable disease, an intact immune system, and a much shorter life span, which allows the achievement of results in a relatively short time. Besides conventional chemotherapy, innovative therapies have a large niche of opportunities. In this article, a comprehensive review of the current research in adjuvant therapies for CMC is conducted to gather available information and evaluate the perspectives. Firstly, updates are provided on the clinical-pathological approach and the use of conventional therapies, to delve later into precision therapies against therapeutic targets such as hormone receptors, tyrosine kinase receptors, p53 tumor suppressor gene, cyclooxygenases, the signaling pathways involved in epithelial-mesenchymal transition, and immunotherapy in different approaches. A comparison of the different investigations on targeted therapies in HBC is also carried out. In the last years, the increasing number of basic research studies of new promising therapeutic agents on CMC cell lines and CMC mouse xenografts is outstanding. As the main conclusion of this review, the lack of effort to bring the in vitro studies into the field of applied clinical research emerges. There is a great need for well-planned large prospective randomized clinical trials in dogs with CMC to obtain valid results for both species, humans and dogs, on the use of new therapies. Following the One Health concept, human and veterinary oncology will have to join forces to take advantage of both the economic and technological resources that are invested in HBC research, together with the innumerable advantages of dogs with CMC as a spontaneous animal model.

Laboratory assessment of trilostane treatment in dogs with pituitary-dependent hyperadrenocorticism.

BACKGROUND: Results of ACTH stimulation test (ACTHst), pre- and post-trilostane serum cortisol concentrations (SCCs), urine concentration (urine-specific gravity [USG]), and urine cortisol : creatinine ratios (UCCRs) are common variables used to monitor trilostane treatment of dogs with pituitary-dependent hyperadrenocorticism (PDH). However, none has consistently discriminated dogs receiving an adequate dose (A) from those overdosed (O) or underdosed (U). OBJECTIVES: To assess and compare recommended monitoring variables, including serial SCCs in a cohort of dogs with PDH treated with trilostane. ANIMALS: Privately owned dogs with PDH (n = 22) and 3 healthy dogs (controls). METHODS: Prospective, multicenter, 2-day study. On day "a" (randomized): ACTHst was completed. Day "b" (>2 to <7 days later): SCCs were assessed -0.5 hours, immediately before, and 1, 2, 2.5, 3, 3.5, 4, 6, 8, and 12 hours after trilostane administration. On the first study day, urine collected at home was assessed for USG, UCCR and owner opinions regarding PDH were categorized as: A (clinical signs resolved), U (remains symptomatic), or ill (possible O). RESULTS: At 27 pairs of evaluations, 7 dogs were categorized as A, 19 U, and 1 possible O (excluded from the study). There was overlap in SCC results from the A and U dogs at every time point. Results of USG, UCCR, and ACTHst did not discriminate A from U dogs. Trilostane suppresses SCC within 1 hour of administration and its duration of action in most PDH dogs is <8 hours. CONCLUSIONS AND CLINICAL IMPORTANCE: No single variable or group of variables reliably discriminated A dogs from U dogs during trilostane treatment for PDH.

Serum and intratumoural GH and IGF-I concentrations: prognostic factors in the outcome of canine mammary cancer.

The biological implication of the growth hormone/insulin like growth factor-I (GH/IGF-I) axis in canine mammary tumours (CMT) has been recently demonstrated, however its clinical and prognostic implications are unknown. Our aim was to investigate its prognostic significance. Hormonal determinations were done by enzyme immunoassays techniques validated for canine species in serum and tumour tissue from 32 bitches with CMT and in serum and normal mammary tissue from 10 controls. Serum and tissular GH and IGF-I concentrations were significantly higher in the case of malignant tumour compared with benign and controls. GH and IGF-I elevated concentrations were significantly associated with tumour relapse and/or metastases during follow-up and in dogs with reduced survival times; however these parameters were not independent prognostic factors in multivariate analysis. This association demonstrates a link between high serum and intratumoural GH and IGF-I concentrations and a worse prognosis and opens the possibility to new anticancer endocrine therapies in dogs.

Positive correlation of steroid hormones and EGF in canine mammary cancer.

There are no published studies focused on the potential crosstalk between steroid hormones and EGF in canine mammary tumourigenesis. The objective was to investigate the role of EGF in canine mammary tumours (CMT) and the relationship with steroid hormones. Sixty-three CMT (39 malignant including 10 inflammatory mammary carcinomas (IMC); 19 benign and 5 dysplasias), and 13 normal mammary glands from dogs without history of neoplastic disease were analysed. Levels of EGF and steroid hormones [progesterone (P4); 17beta-estradiol (E2); androstenedione (A4) and dehydroepiandrosterone (DHEA)], were analysed by EIA in CMT homogenates. Levels of EGF were significantly higher in malignant compared with benign tumours, dysplasias and normal mammary glands (p<0.001). IMC presented the highest EGF levels, with statistical significant difference between IMC and non-IMC cases (p<0.05). Steroid hormone levels were also significantly higher in malignant tumours compared with benign tumours, dysplasias and normal mammary glands (p<0.001). In malignant tumours (non-IMC and IMC), a strong correlation was observed between EGF and: P4 (r=0.452; p=0.003); E2 (r=0.624; p=0.023); A4 (r=0.496; p=0.038); DHEA (r=0.431; p=0.005). These results suggest that EGF is implicated in canine mammary tumourigenesis. The positive correlation observed, opens an interesting perspective of interaction that should be further investigated.

Membranous glomerulonephritis in the Iberian lynx (Lynx pardinus).

The Iberian lynx is the most endangered felid species in the world, confined nowadays to two isolated metapopulations in the southwest of Spain, where less than 200 individuals survive. Little is known about the diseases that affect these animals in the wild or in captivity. Kidney samples from necropsies of 27 Iberian lynxes, wild and captive, were examined by histopathology, immunohistochemistry (IgG, IgM, IgA, laminin, type IV collagen, and fibronectin), electron microscopy (n=8) and immunogold labelling for IgM, IgG and IgA in one case, in order to characterize the glomerulopathy prevalent in this species. Urinalyses from records were available for 9 of the necropsied animals and blood and urine samples from 23 free ranging and captive Iberian lynxes were prospectively obtained in order to evaluate the renal function of the living population. A focal, diffuse membranous glomerulonephritis (MGN) that progressed with age was diagnosed in all but one of the animals in different stages not associated to concurrently known infectious diseases. Positive immunoexpression of IgM and IgG was observed in the glomerular capillary basement membranes and intramembranous electron-dense deposits, compatible with immune complexes (ICs) were seen with electron microscopy. The immunogold labelling was also positive for IgM and IgG in the electron-dense areas. The serum biochemistry and urinalyses also revealed signs of mild chronic kidney disease in 16 of the 23 animals evaluated. In conclusion, the membranous glomerulopathy affecting the Iberian lynx is a progressive disease of immune origin. We postulate a possible genetic predisposition towards the disease, enhanced by inbreeding and a possible connection to an immune-mediated systemic disease.

Steroid pathway and oestrone sulphate production in canine inflammatory mammary carcinoma.

Spontaneous canine mammary inflammatory carcinoma (IMC) shares epidemiologic, histopathologic and clinical characteristics with the inflammatory breast carcinoma (IBC) disease in humans. We have analysed the steroids levels in serum and in tissue homogenates of IMC, the expression of two of their receptors (androgen and beta-estrogen) and of three enzymes included in the steroidogenesis pathway (aromatase (CYP19A1), steroid sulphatase (STS) and estrogen sulfotransferase (EST)) trying to explain the specific accumulation of steroids in IMC tissues generating deposits in the form of lipid droplets whose presence can be attributed to steroids secreted by IMC cells. According to our working hypothesis, oestrone sulphate would be the main component of these lipid droplets. The presence of these steroid deposits would contribute to the intense proliferation and invasive behaviour of IMC and IBC, although their involvement in angiogenesis is yet to be demonstrated.