May 14, 2021, by NCI Staff Cells go through stages of the cell cycle to grow and divide. Specific proteins keep that cycle from spiraling out of control. New research shows that loss of the AMBRA1 protein can lead to uncontrolled cell growth. Credit: BruceBlaus, Wikimedia Commons, CC BY-SA 4.0 At the heart of all cancers is a fundamental problem: a cell—and eventually innumerable cells—that won’t stop dividing. This runaway growth is what forms a tumor, and the abnormal cellular processes that drive this growth can help tumors withstand the cancer treatments intended to kill them. Despite more than six decades of research into the mechanisms that cells use to divide, some of the nuts and bolts of the process remain a mystery. Scientists want to better understand these mechanisms in hopes of targeting them and potentially shutting down the uncontrolled growth of some tumors.