What is the consequence of Netrin-1 receptor loss on signaling pathways as related to cancer risk?

• A. It stabilizes the pathways
• B. It disrupts signaling regulating growth and apoptosis leading to tumor formation
• C. It enhances photosynthesis
• D. It prevents necrosis

Answer: (B)

Netrin-1 receptors act as dependence receptors that help decide cell fate based on whether netrin-1 is present. When netrin-1 is absent, these receptors can trigger apoptotic pathways; when netrin-1 binds, they promote survival and proper growth signaling. If the receptors are lost, the normal balance of growth and programmed cell death is disrupted. The pro-apoptotic signal that would eliminate stressed or misattached cells is weakened, allowing abnormal cells to survive and continue to proliferate, which raises cancer risk. This loss also perturbs growth-regulating signals, contributing to tumor formation. The other options don’t fit because they describe unrelated or opposite effects: stabilizing signaling isn’t the result of receptor loss, photosynthesis isn’t relevant to this signaling context, and preventing necrosis doesn’t capture the essential impact on apoptosis and growth control.