SALL4: engine of cell stemness.

The spalt (sal) family is a class of evolutionarily conserved genes originally identified in Drosophila as homeotic genes required for embryonic development. In vertebrates, the expression of sal-like 4 (SALL4) is specifically enriched in both embryonic and adult stem/stem-like cells. SALL4 is a master regulator that contributes to cell stemness in biological development and tumor growth. Thus, Sall4 has emerged as a target for gene therapy. In addition, numerous mutations affecting the Sall4 gene have been discovered and clinically linked to a series of congenital abnormalities, such as Duane/Duane-related syndromes, ventricular septal defect and premature ovarian failure. This review delineates the underlying mechanisms of key functions of SALL4 and its use as a target for gene therapy. Finally, I summarize and discuss advances made on the application of Sall4 and its functions in diagnostics and treatments for human diseases.