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These findings suggest that over expression of VEGF and its receptor ( VEGFR - 2 ) may play an important role in the initial step of the regulation of estrogen induced tumor angiogenesis in the rat pituitary .
 Chemical: estrogen; Disease: tumor
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: estrogen; Disease: tumor