Background: T-cell factor 3 (transcription factor 7-like 1, TCF-3) is a component of the Wnt signaling pathway, which functions in CNS patterning, proliferation and neurogenesis, and a dominant downstream effector in embryonic stem cells (ESCs). TCF-3 binds to and represses the Oct4 promoter, and plays an important role in modulating the appropriate level of gene transcription in ESCs and during embryonic development (1, 2). TCF-3 is necessary for the terminal differentiation of epidermal cells, the formation of keratohyalin granules and the development of the barrier function of the epidermis. It down-regulates NQO1, leading to increased mitomycin c resistance. It is detected in hair follicles and skin keratinocytes, and at lower levels in stomach epithelium (2).