12842
Recently , CD20-negative tumors have been described after Rituximab therapy .
 adverse effect: CD20-negative tumors, Rituximab
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: adverse effect 
Text: {0} 
 Entity Pairs:  CD20-negative tumors, Rituximab 
Answer:
 adverse effect: CD20-negative tumors, Rituximab