Splenic masses in dogs present a significant diagnostic challenge, as current imaging and clinical tools cannot definitively tell a malignant tumor from a benign one without histopathology. The commonly used “double two-thirds” rule is a general guideline but lacks precision, especially in dogs without hemiperitoneoum. While predictive calculators exist, they are not accurate enough to be the sole basis for a diagnosis. Consequently, vets and owners face difficult decisions, which can lead to unnecessary surgery for a benign mass or a dangerous delay in treating a cancer like hemangiosarcoma.
A recent study investigated a novel, simpler approach: using a panel of four genetic markers found in the blood from a single preoperative blood sample to tell splenic HSA apart from noncancerous splenic masses.
The research identified a panel of four circulating miRNAs—miR-126-5p, miR-150-5p, miR-452-5p, and miR-543—that could distinguish dogs with splenic HSA from those with noncancerous masses with 80% sensitivity and 90% specificity. This high level of accuracy suggests strong potential for this panel to become a valuable preoperative blood test.
The selected miRNAs are not random; each has a plausible biological link to cancer pathways known to be active in HSA. They are involved in processes like promoting blood vessel growth (angiogenesis) and enhancing cancer cell survival, which explains why their levels are distinctly different in dogs with this tumor.
This miRNA panel is a promising candidate for a minimally invasive diagnostic test. For owners of dogs with a splenic mass, a negative result could provide valuable reassurance to proceed with a needed splenectomy. It could also help prevent the difficult decision to euthanize based on a suspected but unconfirmed cancer.
The study does note important limitations. The panel was designed specifically to differentiate HSA from noncancerous masses and was not tested against other types of splenic tumors. Furthermore, the study was relatively small, meaning larger validation studies are needed to confirm these results.
The discovery of this circulating miRNA panel is a significant step toward a definitive, non-surgical test for splenic hemangiosarcoma. While further validation is required, this approach holds real promise for improving decision-making. It could enable earlier diagnosis of HSA—when it is more treatable—while also providing confidence to surgically treat dogs with benign splenic disease.
