DOES PROLIFERATION IN CANINE NEOPLASMS VARY WITH PATIENT AGE, SEX OR NEUTERING STATUS? T.C. Firsching, K. Dietert and A.D. Gruber Department of Veterinary Pathology, Freie Universitaet Berlin, Germany Introduction: Proliferation is a key parameter for assessing malig- nancy in general, or tumour grade in particular, in veterinary oncology. In human medicine, several studies have indicated that proliferation of various neoplasms as well as normal tissues varies with the age of the patient. Here, we tested for variations in prolifer- ation in canine tumours associated with different age, sex and neuter- ing status. Materials and Methods: The study included 353 cases of common canine neoplasms, such as hepatoid gland adenomas (n 5 95), Leydig cell tumors (n 5 65), Sertoli cell tumours (n 5 45), canine cutaneous soft tissue sarcomas (n 5 37), trichoblastomas (n 5 48) and plasma- cytomas (n 5 63). Proliferation was quantified using digital image analysis, specifically nuclear quantification software, from tissues im- munohistochemically labelled for Ki67 with the MIB1 antibody. For evaluation of proliferative activity, we used the Ki67 labelling index (Ki67-LI in %). Results: In hepatoid gland adenomas, Ki67-LI showed a significant relative increase of 8.1% per year of age. Comparing male and female entire and neutered dogs, Ki67-LI was significantly higher in male dogs (male: mean 4.73; female: mean 2.45). Additionally, entire male dogs with plasmacytomas had higher Ki67-LI (mean: 18.95) than their neutered counterparts (mean: 12.68). Conclusions: Our data suggest that in some types of tumours prolif- eration varies with different age, sex and neutering status of the pa- tient, as observed in human medicine. As a consequence, estimation of proliferation for assessing malignancy or tumour grade may have to be corrected for age. Clearly, similar studies are now imperative for other tumour types where proliferation is relevant, such as mela- noma and mast cell tumours. DETECTION AND LOCALIZATION OF CHEMORESISTANCE MARKERS PGP AND BCRP: IMMUNOCYTOCHEMISTRY ON CANINE MAMMARY CANCER CELL LINES M. Levi * , R. De Maria y , R. Salaroli * , M. Forni * , C. Bernardini * , F. Parenti * , L.V. Muscatello * , C. Benazzi * , B. Brunetti * and G. Sarli * *Department of Veterinary Medical Sciences, University of Bologna and y Department of Veterinary Medicine, Animal Pathology, University of Turin, Italy Introduction: Multidrug resistance of neoplastic mammary cells is frequently attributed to the expression of P-glycoprotein (PGP) and breast cancer resistance protein (BCRP) transmembrane-efflux pumps. Immunocytochemistry (ICC) could be a valuable technique for assessing PGP and BCRP expression, because it reflects the subcel- lular localization of these pumps. Materials and Methods: Specificity of PGP (clone C494) and BCRP (clone BXP21) antibodies in canine tissues was assessed by western blot (WB). Five canine mammary cancer (CMC) cell lines (CYP-P, CYP- M, U27, LILLY, CTB) were cultured in basic conditions and formalin- fixed paraffin wax-embedded pellets were obtained. ICC for PGP and BCRP was performed on pellets. The percentage of labelled cells and the localization of labelling was evaluated semiquantitatively. Accord- ing to the literature, tumours are positive when O20% and O10% of cells are labelled for PGP and BCRP, respectively. Results: WB proved that the employed antibodies are specific for de- tecting canine PGP and BCRP, generating a specific band close to the expected molecular weight of 142kDa and 72kDa, respectively. ICC on pellets showed that all CMC cell lines had a high number of cells showing membranous labelling for PGP and BCRP, ranging from 30 to 100% and 30 to 70%, respectively. Conclusions: ICC evaluation of PGP and BCRP on CMC cell lines in pellets allows identification of the percentage of labelled cells and the subcellular localization of these pumps. In all cell lines a high number of CMC cells express these markers at the cell membrane, suggesting that CMCs can often bear chemoresistance. RESUMEQ: A NOVEL WAY OF MONITORING EQUINE DISEASES VIA THE CENTRALIZATION OF NECROPSY DATA I. Tapprest * , N. Foucher * , M. Linster * , J. Amat y , E. Laloy z , N. Cordonnier z and P. Hendrikx y *Laboratory for Equine Diseases, French Agency for Food, Environmental and Occupational Health and Safety (Anses), y Co-ordination and Support Unit for Surveillance, French Agency for Food, Environmental and Occupational Health and Safety (Anses) and z Department of Pathology, Ecole Nationale V  et  erinaire d’Alfort, France Introduction: The French surveillance network of equine mortality causes (Resumeq) was created in 2015 for the qualitative surveillance of equine mortality through the centralization of necropsy data in a national database and their overall epidemiological analysis. Its objectives are the qualification of the causes of equine mortality, the monitoring of their evo- lution over time and space and the early detection of emerging diseases. Materials and Methods: Resumeq is an event-based surveillance system that involves a diversity of actors and structures. An institu- tional organization has been defined that includes a steering commit- tee, a scientific and technical support committee and a coordination unit. Several specific tools have been developed such as standardized necropsy protocols, a thesaurus for the anatomopathological terms and the causes of equine death, and an interactive web application for the visualization of data analysis by the contributors. Results: The four French veterinary schools, 16 veterinary laboratories and nine veterinary clinics already contribute to the production and centralization of standardized data. To date, around 1,000 cases have been collected. They are mainly located in the west part of France; the geographical coverage is gradually improving. Data analysis allows the ranking of the main causes of death and the identification of partic- ularly threatening causes of death at a local, regional and national level. Conclusions: These first results demonstrate the feasibility and in- terest of this surveillance at a national level. Moreover, this surveil- lance could take an international dimension if several countries decided to evaluate their necropsy data jointly. BLASTOCYSTIS IN SWISS PIGS T. Sydler * , F. Grimm y , G. Rosato * , S. Polster * , M. Hilbe * , S. Klausmann z , D. Hadorn x and W. Basso { *Institute of Veterinary Pathology, Vetsuisse Faculty Zuerich, y Institute of Parasitology, Vetsuisse Faculty Zuerich, z SUISAG SGD Zuerich, x Federal Food Safety and Veterinary Office, Bern and { Institute of Parasitology, Vetsuisse Faculty Bern, Switzerland Introduction: Blastocystis, a worldwide distributed enteric eukaryotic parasite of man, pigs and other animal species, may be involved in diarrhoeal disease. Materials and Methods: By histopathology and semiquantitative coproscopical analysis, high amounts of Blastocystis were detected inci- dentally in piglets with diarrhoea and confirmed rotavirus infection (PCR on faeces) in a Swiss farm (Farm 1). Subsequently, necropsied pigs were systematically analysed for Blastocystis by the sodium acetate eacetic acid formalineconcentration (SAFC) method, independently of age and diarrhoea status, to obtain data on the prevalence of Blas- tocystis infection in Swiss pigs. Faeces of 155 pigs (65 suckling piglets, 57 weaned piglets, 32 fattening pigs and seven adults) from 104 farms were investigated. Additionally, faecal samples from 14 animals from Farm 1 were analysed by PCR (18S rRNA) followed by direct sequencing in order to recognise the Blastocystis subtypes present on the farm. Results: The prevalence of Blastocystis infection at the animal level was 35% and at the farm level 39%. Prevalence in suckling pigs was 12%, in weaned pigs 55%, in fattening pigs 52% and in adults 43%. On Farm 1, Blastocystis was detected by SAFC in 0/2 sows, 2/ 7 suckling and 6/6 weaning piglets. Half of the positive animals had diarrhoea. By PCR/sequencing, two subtypes were detected: ST2 in one suckling and ST5 in one weaning piglet. The remaining animals had mixed infections. Conclusions: In Swiss pigs the prevalence of Blastocystis seems to be high. First studies on genetic characterization revealed the presence of at least two zoonotic Blastocystis subtypes and mixed infections. J. Comp. Path. 2019, Vol. 166, 100e122 ESVP, ESTP and ECVP Proceedings 2017 115