Beclin-1 predictive effect is concentrated in Kiupel high-grade MCTs. High Beclin-1 expression is associated with shorter survival in which grade category?

• A. Kiupel LOW-grade MCTs
• B. Kiupel HIGH-grade MCTs
• C. All grades equally
• D. Only primary tumors

Answer: (B)

Beclin-1 is a marker of autophagy, a process that helps cells survive stress. In canine mast cell tumors, its prognostic value isn’t the same across all Kiupel grades—the strongest link between high Beclin-1 and worse outcomes appears in tumors that are already high-grade. High-grade tumors rely more on autophagy to cope with rapid growth and stress, so elevated Beclin-1 signals a more aggressive biology and is associated with shorter survival. In low-grade tumors, autophagy levels marked by Beclin-1 don’t predict survival as clearly, so the association isn’t as strong. Thus, the grade category where high Beclin-1 predicts shorter survival is Kiupel high-grade MCTs.