Journal Article

DNA Repair Deficiency as a Susceptibility Marker for Spontaneous Lymphoma in Golden Retriever Dogs: A Case-Control Study

Grunerud, Kristen K., Rose, Barbara J., Thamm, Douglas H., Vail, David M., Bailey, Susan M.

2013

Overview

There is accumulating evidence that an individual's inability to accurately repair DNA damage in a timely fashion may in part dictate a predisposition to cancer. Dogs spontaneously develop lymphoproliferative diseases such as lymphoma, with the golden retriever (GR) breed being at especially high risk. Mechanisms underlying such breed susceptibility are largely unknown; however, studies of heritable cancer predisposition in dogs may be much more straightforward than similar studies in humans, owing to a high degree of inbreeding and more limited genetic heterogeneity. Here, we conducted a pilot study with 21 GR with lymphoma, 20 age-matched healthy GR and 20 age-matched healthy mixed-breed dogs (MBD) to evaluate DNA repair capability following exposure to either ionizing radiation (IR) or the chemical mutagen bleomycin. Inter-individual variation in DNA repair capacity was evaluated in stimulated canine lymphoctyes exposed in vitro utilizing the G2 chromosomal radiosensitivity assay to quantify clastogen-induced chromatid-type aberrations (gaps and breaks). Golden retrievers with lymphoma demonstrated elevated sensitivity to induction of chromosome damage following either challenge compared to either healthy GR or MBD at multiple doses and time points. Using the 75(th) percentile of chromatid breaks per 1,000 chromosomes in the MBD population at 4 hours post 1.0 Gy IR exposure as a benchmark to compare cases and controls, GR with lymphoma were more likely than healthy GR to be classified as \"sensitive\" (odds ratio = 21.2, 95% confidence interval 2.3-195.8). Furthermore, our preliminary findings imply individual (rather than breed) susceptibility, and suggest that deficiencies in heritable factors related to DNA repair capabilities may be involved in the development of canine lymphoma. These studies set the stage for larger confirmatory studies, as well as candidate-based approaches to probe specific genetic susceptibility factors.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Aberration / Animals / Biomarkers - metabolism / Bleomycin / Cancer / Case-Control Studies / Chromatids - metabolism / Chromosome Aberrations / Chromosomes / Confidence intervals / Damage / Deoxyribonucleic acid / Development and progression / Disease susceptibility / Disease Susceptibility - pathology / DNA / DNA damage / DNA repair / DNA Repair-Deficiency Disorders - pathology / DNA Repair-Deficiency Disorders - veterinary / Dogs / Exposure / Genetic aspects / Genetic research / Heterogeneity / I.R. radiation / Immunoproliferative diseases / Inbreeding / Ionizing radiation / Iridium / Lymphocytes / Lymphocytes - drug effects / Lymphocytes - pathology / Lymphocytes - radiation effects / Lymphoma / Lymphoma - pathology / Lymphoma - veterinary / Mutagens - toxicity / Mutation / Non-Hodgkin's lymphomas / Oncology, Experimental / Radiation / Radiation, Ionizing / Radiosensitivity / Repair / Veterinary colleges