Normal cells have a complex system of checks and balances that regulate cell division. In cancer, the balance is tipped in favor of cell proliferation. This imbalance arises from increased levels or activity of oncoproteins (proteins that promote cell growth) or decreased levels or activity of tumor suppressors (proteins that limit cell growth). For example, in normal cells, the tumor suppressor protein phosphatase 2 (PP2A) controls cell growth, migration and immortalization to keep cells in check. Some cancers, such as lung cancer, have higher levels of an oncoprotein with the unwieldy moniker su(var)3-9, enhancer of zeste, trithorax (SET). SET binds PP2A and inhibits the normal function of PP2A, resulting in loss of the checkpoint for cancer growth.
* This article was originally published here
