Incidence and Heritability of Gastric Carcinoma in the Belgian Shepherd Dog Population in The Netherlands

Background: Gastric carcinoma in the Belgian Shepherd dog varieties Tervueren and Groenendael is commonly recognized and carries a grave prognosis. Information on incidence and heritability is necessary to design an effective selection strategy against this disease. Methods: A database of cases and controls was built including cases with tier 1 (confirmed by endoscopy or post-mortem) and tier 2 evidence of gastric carcinoma. From the database, a birth cohort from dogs born in the Netherlands in the period 2000-2010 was used, together with pedigree information to calculate heritability using a mixed models approach. Univariate linear regression was used to test the influence of gastric carcinoma status of the parents on gastric carcinoma occurrence in offspring. Results: For Tervueren the 10-year cumulative incidence is 4.7%, for the Groenendael this was 2.1%. There was no sex predilection. The odds of gastric carcinoma were 5.0 (2.4-11.0) in offspring when at least one parent was known to be affected versus at least one parent was known to be unaffected. Heritability, based on analysis using pedigree information from 338 dogs with gastric carcinoma and 159 controls was 0.53 (se 0.15). Conclusions: Gastric carcinoma in the Belgian Shepherd Tervueren and Groenendael has a high incidence in the Dutch population and has a strong genetic component. Because it is a late onset disease, dogs are often already used for breeding before they are diagnosed. An effective breeding strategy for reducing the incidence therefore relies on the identification of genetic risk factors influencing the development of the disease.