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: Surgery
Alpha feto protein is elevated in what percentage of children with hepatoblastoma: 
Select and explain. 
A. 10%, B. 50%, C. 90%, D. 100%
C: 90%
Answer: C: 90% 
Explanation: Most liver function test results are normal. Alpha-fetoprotein levels are increased in 90% of children with hepatoblastomas but are elevated much less commonly in children with other liver malignancies. Ref: Schwaz's principle of surgery 9th edition, chapter 39.