Amassing detailed information about which human genes play a role in cancer and what their roles are is central to many efforts to fight the disease. One of the most promising new approaches to the identification of cancer-causing genes is called RNA interference, a method for suppressing genes to learn their functions. But RNAi is costly, and silences genes for only a few days at a time – not long enough for researchers to study slow-developing diseases. Thijn Brummelkamp has developed an inexpensive way to make the effect last, silencing a single gene indefinitely. Brummelkamps work “will lead to new treatments” for cancer, says MIT biologist and Nobel laureate Phillip Sharp.