B-cell lymphoma is the second most common type of cancer in dogs, clinically comparable to human non-Hodgkin lymphoma. The factors influencing canine lymphoma progression are complex and not fully understood, but evidence suggests that genetic mutations play a significant role (1).
A study using Next Gen DNA sequencing of six dogs with multicentric B-cell lymphoma undergoing CHOP chemotherapy identified a variety of genetic variants that could potentially impact the disease's progression. The genes with variants had human orthologs linked to cancer, but most of the variants had not been previously reported in canine or human lymphoma. Several genes had variants in at least two 'poor responders' to chemotherapy but not in 'good responders', indicating that these genetic variations may be associated with the disease's progression (1).
Another study performed an integrated analysis of exome and RNA sequencing data from a cohort of dogs with Diffuse Large B-Cell Lymphoma (DLBCL), the most common lymphoid neoplasm in both dogs and humans. The research revealed a wide range of signaling pathways and cellular processes in common with human DLBCL, although the frequencies of the most recurrently mutated genes differed. This study also aimed to develop a prognostic model integrating exonic variants, clinical, and transcriptomic features to predict the outcome in dogs with DLBCL (2).
Research into the interplay between genetic mutations and exposure to environmental toxins has also been conducted, as both are suspected causes of canine lymphoma. A study on Boxers, a breed with a high risk of lymphoma, examined whether inherited mutations that affect enzymes responsible for breaking down toxic chemicals could increase lymphoma risk. This study found no breed-specific accumulation of DNA damage or significant differences in the number of low-activity GST enzymes, which process and break down toxic chemicals, suggesting that the high lymphoma risk in Boxers may not be related to these factors (3).
However, the study did find that Boxers living within certain distances of a nuclear power plant, crematorium, or chemical manufacturer were more likely to develop lymphoma, supporting the hypothesis that exposure to environmental chemicals and industrial waste contributes to lymphoma risk in dogs (3).
Further research is needed to deepen understanding of the interactions between genotype and environmental exposures in dogs with lymphoma. Currently, studies are being conducted to explore the amount and characteristics of genetic mutation accumulations in various types of canine lymphoma, which could pave the way for future prevention and treatment strategies (3).
The exact genetic mechanisms and heritability of lymphoma in dogs are not entirely understood, and this disease is likely influenced by a complex interplay of genetic and environmental factors (1, 2, 3). Therefore, a family history of lymphoma doesn't necessarily guarantee that a dog will develop the disease, but it maybe may increase the risk.
Any breeder dealing with this issue should stay informed about ongoing research in this area, as our understanding of the genetic aspects of canine lymphoma is still evolving and new information may become available that could inform breeding decisions.
Sources:
1) https://pubmed.ncbi.nlm.nih.gov/32857815/
2) https://www.nature.com/articles/s41684-022-00998-x
3) https://www.akcchf.org/educational-resources/library/articles/exploring-risk-factors-for.html