Published online Nov 14, 2015. doi: 10.3748/wjg.v21.i42.12150
Peer-review started: March 31, 2015
First decision: May 18, 2015
Revised: May 30, 2015
Accepted: August 31, 2015
Article in press: August 31, 2015
Published online: November 14, 2015
Core tip: A well-known tumor suppressor, p21, can act paradoxically by promoting tumor growth, depending on its subcellular localization. Nuclear p21 may inhibit cell proliferation while cytoplasmic p21 may be associated with anti-apoptotic and oncogenic functions. These conflicting roles are reviewed in the context of the HBx gene and hepatocarcinogenesis. Because most tumor suppressors act in a similar manner to p21, regulation of their nucleo-cytoplasmic export, which is mainly effected via chromosome region maintenance 1, may be a basis for developing a new strategy for anti-hepatocellular carcinoma therapy.