5427
In conclusion , more data are needed regarding BDNF in the brain and in peripheral blood , including protein levels , single nucleotide polymorphisms , epigenetic regulation , and clinical data in order to understand the role of BDNF in schizophrenia .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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