This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pancreas, Subject name: Pathology
Marker for pancreatic non-functional neuro endocrine tumor (PNET) is? 
Select and explain. 
A. Chromogranin-A, B. CD100, C. CEA, D. PSA
A: Chromogranin-A
Answer: A: Chromogranin-A 
Explanation: Ans is 'a' i.e. Chromogranin-A o Chromogranin-A (CgA) is a glycoprotein used commonly as a tumor marker in histopathology but also has elevated circulating levels in patients with both functional and non-functional PNETs.o Other markers for PNETs - pancreatic polypeptide (PPP), pancreastatin, and neuron-specific enolase (NSE)