ACTR3 and cancer: Colorectal cancer has become the third leading cause of cancer-related deaths in humans, accounting for 8.7% of all cancer deaths.[1] By immunohistochemistry, Otsubo et al[53] discovered significant overexpression of Arp2 and Arp3 proteins in cancer cells and stromal cells in 175 colorectal cancer specimens, whereas Arp2 and Arp3 were not expressed in normal colorectal mucosal epithelial or stromal cells.