This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenal Gland, Subject name: Pathology
MEN1 tumour suppressor gene is associated with all of the following, except: 
Select and explain. 
A. Menin, B. JunD, C. KMT2A (MLL), D. GDNF (glial-derived neurotrophic factor)
D: GDNF (glial-derived neurotrophic factor)
Answer: D: GDNF (glial-derived neurotrophic factor) 
Explanation: MEN-1 syndrome Caused by germline mutations in the MEN1 tumor suppressor gene, which encodes a protein called menin. The dichotomy in menin function is best exemplified in the interactions of menin with two oncogenic transcription factors: JunD Mixed lineage leukemia (MLL)/KMT2A protein. RET proto-oncogene in MEN-2 syndrome encodes a receptor tyrosine kinase that binds glial-derived neurotrophic factor (GDNF).