A 45-year-old man with neurofibromatosis type 2 (NF2) develops bilateral acoustic neuromas. NF2 gene encodes which tumor suppressor protein?

• A Neurofibromin — a RAS-GAP protein accelerating RAS GTP hydrolysis
• B PTEN — a lipid phosphatase antagonizing PI3K/AKT signalling
• C Merlin (schwannomin) — an ERM-family protein linking cell surface to cytoskeleton ✓
• D VHL — an E3 ubiquitin ligase targeting HIF-1alpha

Explanation

NF2 encodes merlin (schwannomin), a member of the ERM (ezrin-radixin-moesin) family that connects membrane proteins to the actin cytoskeleton, acting as a tumor suppressor by regulating contact inhibition of growth via Hippo pathway and other mechanisms. Loss of merlin leads to schwannomas, meningiomas, and ependymomas. Neurofibromin is the NF1 product, a RAS-GTPase activating protein (RAS-GAP). PTEN loss is associated with Cowden syndrome and multiple cancers. VHL loss causes clear cell renal carcinoma and hemangioblastomas in von Hippel-Lindau disease.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.