14-3-3 protein epsilon isoform (isoform (also known as tyrosine 3-monooxygenase/ tryptophan 5-monooxygenase activation protein, epsilon polypeptide) is encoded by the YWHAE gene in humans and is involved in cancer cell survival and growth. It interacts with CDC25 phosphatases, RAF1 and IRS1 proteins, suggesting its role in diverse biochemical activities related to signal transduction, such as cell division and regulation of insulin sensitivity. Overexpression of 14-3-3 epsilon in primary hepatocellular carcinoma (HCC) tissues predicts a high risk of extrahepatic metastasis and worse survival, and is a potential therapeutic target. It has also been implicated in the pathogenesis of small cell lung cancer. 14-3-3 epsilon overexpression protects colorectal cancer and endothelial cells from oxidative stress-induced apoptosis, while its suppression by non-steroidal anti-inflammatory drugs induces cancer and endothelial cell death. Cellular levels of 14-3-3 epsilon could possibly serve as an important regulator of cell survival in response to oxidative stress and other death signals. 14-3-3 domains are an essential part of 14-3-3 proteins, a ubiquitous class of regulatory, phosphoserine/threonine-binding proteins found in all eukaryotic cells, including yeast, protozoa and mammalian cells.