Methods to Detect DNA in the Blood of Human Cancer Patients Provide an Avenue for Novel Diagnostics in Dogs With Cancer
Originally published in Scientific Reports in April 2022
The full journal article is available in Scientific Reports in April 2022 titled “Feasibility of circulating tumor DNA analysis in dogs with naturally occurring malignant and benign splenic lesions.”
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Hemangiosarcoma is an aggressive cancer of dogs that most commonly develops in the spleen. This is a cancer of blood vessels that causes severe internal bleeding when the tumor ruptures. A major challenge of this disease is the lack of early diagnostic tests to discover the cancer prior to tumor rupture. Also, benign splenic tumors often are indistinguishable from hemangiosarcoma making the diagnosis dependent on surgery in most cases.
Circulating Tumor DNA
DNA leaks from dying cells throughout the body and ends up in the bloodstream. This occurs for both normal and cancerous cells. Cancer results from DNA ‘misshaps’ like mutations and copy number changes in critical genes. Various tools have been developed to detect these DNA changes from the pool of circulating DNA in the bloodstream to detect cancer.
In this study, tools previously validated for use in people were used to detect circulating tumor DNA (ctDNA) in the blood of dogs with splenic hemangiosarcoma. These tools were found to be useable in dogs with cancer as well. On average, dogs with metastatic disease had higher levels of ctDNA and dogs who had their splenic tumor surgically removed were found to have lower levels of ctDNA after surgery. Furthermore, dogs with a benign splenic tumor had significantly lower ctDNA compared to dogs with hemangiosarcoma. This study demonstrates that ctDNA is useful in dogs with cancer and will serve as the foundation for future studies.