TCF-4, transcription factor 4, is a basic helix-turn-helix transcription factor. This protein recognizes an Ephrussi-box ('E-box') binding site ('CANNTG') - a motif first identified in immunoglobulin enhancers. The gene for TCF-4 is expressed predominantly in pre-B-cells, although it is found in other tissues as well. Multiple alternatively spliced transcript variants that encode different proteins have been described. TCF4, also known as TCF7L2, is expressed widely during development. Gene targeting study indicates that it is required to maintain the crypt stem cells of the small intestine. TCF4 has many different splicing isoforms and they are expressed differentially in tissues and in cancers of different stages. Studies also indicate that variant of the TCF4 gene confers an increased risk of type 2 diabetes.