Introduction

Elevated plasma nucleosome concentrations (PNC) have been documented in newly diagnosed canine lymphoma and hemangiosarcoma patients. Nucleosomes have a short half-life in plasma, making them a useful surrogate for treatment response and remission monitoring. The objective of this study was to prospectively evaluate PNCs in dogs with a variety of cancers undergoing definitive therapy to determine the utility of this assay as a treatment and remission monitoring tool.

Methods

Dogs with a variety of newly diagnosed malignancies undergoing definitive therapy were enrolled in this study. Plasma was collected at diagnosis and at each treatment and recheck visit thereafter. Samples were processed as previously described. Data from medical records including response to treatment, laboratory data, imaging results and quality of life information was collected and compared to PNCs.

Results

Here we present a series of twenty dogs with a variety of cancers, including hematopoietic, mesenchymal and epithelial tumors, with PNCs that mirror treatment response and disease progression. The median PNC at diagnosis for all dogs was 203.7 ng/mL. PNCs at clinical remission (CR) or best clinical response was 48.6 ng/mL. All dogs achieving a CR had PNCs that dropped into the healthy range. Elevated nucleosome concentrations were identified after treatment delays in cases of lymphoma and prior to clinical progression in some lymphoid and non-lymphoid malignancies.

Conclusion

Plasma nucleosome concentrations can mirror treatment response and disease progression for a variety of malignancies in canines and may serve as a useful monitoring and potentially actionable tool for cancer patients undergoing treatment.

Funding Information

Funding for this study was provided in part by Volition America and by the Fred and Vola Palmer Chair for Comparative Oncology.