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 seque ntial 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 conf ined to the 30-mu m-wide strip below the epidermis. A different mast c ell phenotype appeared in this area, compatible with an MMC-like pheno type. During the carcinogenesis process, the mast cell population is c omprised of two distinct subpopulations that appeared simultaneously i n the same tissue, i.e. connective tissue mast cells, normally found i n the skin of mice, and the newly formed mucosal mast cell-like cells, currently found in gastrointestinal mucosa.