Beclin-1 is a novel predictive biomarker for which tumor type?

• A. Feline leukemia.
• B. Canine osteosarcoma.
• C. Feline gastrointestinal lymphoma.
• D. Canine cutaneous and subcutaneous mast cell tumors.

Answer: (D)

Beclin-1 is a key regulator of autophagy, a process that helps cells survive under stress and can influence cancer behavior and treatment responses. In canine oncology, Beclin-1 expression has been studied as a predictive biomarker specifically in canine cutaneous and subcutaneous mast cell tumors, where its levels have been associated with tumor aggressiveness and clinical outcomes. This makes canine mast cell tumors the tumor type where Beclin-1 has shown the most support as a predictive marker, unlike feline leukemia, canine osteosarcoma, or feline gastrointestinal lymphoma, for which this biomarker’s predictive value is not established in the same way.