This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Tumor, Subject name: Pathology
All of the following are seen in follicular carcinoma of thryoid, except: 
Select and explain. 
A. PAX8-PPARG fusion, B. RAS gene mutations, C. Point mutations of TP53, D. Loss-of-function mutations of PTEN gene
C: Point mutations of TP53
Answer: C: Point mutations of TP53 
Explanation: Genetics of follicular thyroid carcinomas: 30% to 50% of follicular carcinomas harbor RAS mutation. 20% to 50% of follicular carcinomas harbor PAX8-PPARG fusion. Up to 10% of follicular carcinomas exhibit gain-of-function mutations of PIK3CA (the gene that encodes phosphoinositide 3-kinase ) or loss-of-function mutations of PTEN, a tumor suppressor gene and negative regulator of PI3K pathway. Point mutations of TP53, beta-catenin (CTNNB1), and TE are seen in poorly differentiated and anaplastic carcinomas.