In this task, you will be given sentences in which your task is to recognize the name of the organ of the body. An organ is a collection of tissues that structurally form a functional unit specialized to perform a particular function. Although there might be several correct answers, you need to write one of them.
Q:  alpha2M promotes the protease - mediated degradation of alpha2M / Abeta complexes and contributes to clearance of Abeta from the brain ( discussed in paragraph 4 ) [ 138 , 139 ] .
A:
brain