Pet dogs develop spontaneous diffuse large B cell lymphoma (DLBCL), a condition that not only afflicts canine patients but also serves as an informative model for human lymphomas. In veterinary clinical trials, various treatment strategies have been evaluated to improve outcomes in canine DLBCL, thereby offering valuable insights that can guide human clinical research. Despite advances in treatment, a major challenge remains in selecting the most effective therapy to enhance patient survival and quality of life.

In this study, dogs enrolled in a larger clinical trial received combinations of doxorubicin chemotherapy, an anti-CD20 monoclonal antibody, and one of three small molecule inhibitors: KPT-9274, TAK-981, or RV1001. We hypothesized that differential expression of specific genes in tumor samples at baseline could predict which animals would respond favorably to each treatment regimen, reflecting the molecular pathways targeted by these drugs. To test this hypothesis, gene expression in lymph node aspirates from 18 trial dogs was analyzed using the NanoString nCounter Canine Immuno-oncology (IO) Panel. For the purpose of the study, dogs were classified as good responders if they relapsed after 90 days, and as poor responders if they relapsed before 90 days.

Comparative analysis between poor and good responders revealed that increased expression of CCND3 was associated with a poor prognosis, while elevated levels of CD36 correlated with a better prognosis, mirroring findings observed in human DLBCL. Interestingly, there was minimal overlap in differentially expressed genes across the different treatment arms, which prompted us to perform separate analyses for each therapeutic cohort. In the group treated with KPT-9274, higher levels of CREBBP and CDKN1A were linked to improved outcomes. For those receiving TAK-981, increased TLR3 expression was indicative of a favorable prognosis, while in the RV1001 cohort, a profile marked by elevated PI3Kδ, AKT3, and PTEN and reduced NRAS expression was associated with better clinical results. These trends for selected candidate biomarker genes were subsequently validated via qPCR.

Overall, our findings underscore the heterogeneity inherent in DLBCL and highlight both similarities and differences between canine and human forms of the disease. The identified biomarkers may offer a pathway toward more personalized chemoimmunotherapy strategies in dogs, potentially improving treatment selection and outcomes. This adipocentric approach in biomarker discovery not only advances our understanding of DLBCL biology but also holds promise for translating these insights into more effective therapeutic interventions for both canine and human patients. KPT 9274