This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Pathology
The tumor marker for Endodermal sinus tumor is 
Select and explain. 
A. HCG, B. CEA, C. cytokein, D. Alpha fetoprotein
D: Alpha fetoprotein
Answer: D: Alpha fetoprotein 
Explanation: Endodermal sinus Tumors often have eosinophilic hyaline globules in which a1-antitrypsin and alpha fetoprotein (AFP) can be demonstrated by immunohistochemical techniques. As mentioned later, AFP can also be detected in the serum .Serum AFP is a very good tumor marker in patients with germ cell tumors composed of or containing endodermal sinus (yolk sac) tumor, irrespective of their location. ref : Robbins Basic Pathology, 9E,page-661