c-Myc and epidermal stem cell fate determination.

The epidermis is sustained by a multipotent stem cell population that gives rise to cells of different fates including those forming hair follicles, interfollicular epidermis and associated glands such as sebaceous glands. The most intriguing evidence comes from using a variety of mouse models with which studies have found the WNT pathway to be involved in regulating stem cell fate decisions. These mouse models have been used to analyze different members of the WNT pathway in the epidermis and altogether suggest that different levels of beta-catenin correlate with the adoption of different epidermal stem cell fates. Recent data specifically analyzing c-Myc, a downstream target of the WNT pathway, has found that c-Myc can divert epidermal stem cells to a sebaceous gland fate at the expense of hair follicles. Also, newly emerging data using gene expression profiling techniques have uncovered a more direct role of c-Myc in stem cell fate determination.