Mast cell phenotypic changes in skin of mice during benzoyl peroxide-induced tumor promotion.

The behavior of the mast cell population was analyzed during the sequential changes that normal mice skin undergoes during experimental two-stage carcinogenesis. Our study reveals that the number of mast cells increased during the promotion period but that this alteration is confined to the 30-microns-wide strip below the epidermis. A different mast cell phenotype appeared in this area, compatible with an MMC-like phenotype. During the carcinogenesis process, the mast cell population is comprised of two distinct subpopulations that appeared simultaneously in the same tissue, i.e. connective tissue mast cells, normally found in the skin of mice, and the newly formed mucosal mast cell-like cells, currently found in gastrointestinal mucosa.