This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Which gene is mutated in Cowden syndrome? 
Select and explain. 
A. SMAD 2, B. PTCH, C. PTEN, D. APC
C: PTEN
Answer: C: PTEN 
Explanation: Cowden syndrome is also known as multiple hamartoma - neoplasia syndrome.
It is due to PTEN gene mutation. It increases the risk of Ca Breast, Ca endometrium and thyroid cancers.