Considering that both LMP1 and UCH-L1 have been detected in exosomal fractions from cancer cells (30, 82), we suggested that UCH-L1 is a part of the exosomal cargo-sorting machinery and that either deubiquitinating activity or membrane-anchoring ability (C-terminal farnesylation) of UCH-L1 is involved in the process of the sorting. Here, UCHL1 is linked to cancer.