How does Beclin-1 expression change with disease progression in MCTs?

• A. It increases, with the lowest in primary tumors and the highest in lymph node metastases
• B. It decreases
• C. It stays the same across stages
• D. It fluctuates unpredictably

Answer: (A)

Beclin-1 is a key regulator of autophagy, a cellular recycling process that helps cancer cells survive stress during growth and especially during invasion and metastasis. In mast cell tumors, the amount of Beclin-1 tends to rise as the disease advances. The smallest levels are found in primary tumors, with progressively higher levels in metastatic sites such as lymph nodes. This pattern fits with autophagy supporting tumor cells as they detach, endure nutrient limitations, and colonize new environments, making higher Beclin-1 advantageous in metastases. While Beclin-1 can be downregulated in some cancers, acting as a tumor suppressor, in this context the data align with increasing Beclin-1 expression as MCTs progress to metastasis.