Beclin-1 testing could specifically help guide the decision to pursue adjunctive therapy for which 'gray area' tumors?

• A. Kiupel high-grade MCTs
• B. Patnaik Grade II dermal MCTs and subcutaneous MCTs with mitotic counts near the cutoff of 4
• C. Patnaik Grade I cutaneous MCTs
• D. Kiupel low-grade MCTs

Answer: (B)

Beclin-1 testing serves as a prognostic tool to clarify risk in canine mast cell tumors where the biology isn’t clear from histology alone. In the Patnaik system, the gray-area tumors are those that are Grade II and subcutaneous tumors with mitotic counts around the cutoff of four. These cases sit in a prognostic middle ground: some behave aggressively, others less so, and traditional grading can’t reliably predict outcome. Beclin-1, which relates to autophagy and tumor biology, can help stratify these ambiguous tumors and guide whether adding adjunctive therapy beyond surgery is warranted.

In contrast, clearly benign tumors (like low-grade or low-risk lesions) usually don’t require adjunctive therapy, and clearly high-grade tumors already push toward aggressive treatment regardless of Beclin-1 status, so the test wouldn’t add meaningful guidance in those groups.