6656
Overexpression of P - glycoprotein ( P - gp ) and multidrug resistance - associate protein 1 ( MRP1 ) is a major mechanism leading to multidrug resistance ( MDR ) of cancer cells .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None