Abstract: Objective To detect the expression intensity and distribution of minichromosome maintenance 2 protein （MCM-2） in normal skin and lesions of malignant and non-malignant hyperplasia. Methods Three groups of samples were collected, i.e., malignant group （including 15 cases of Bowen disease or highly differentiated squamous cell carcinoma of Grade Ⅰ or Ⅱ）, non-malignant group （including 4 cases of chromomycosis, 2 cases of sporotrichosis, 5 cases of seborrheic keratosis, 4 cases of verruca vulgaris, 4 cases of chronic eczema, 4 cases of cutaneous fibroma）, and normal group （10 cases of normal human control）. The distribution and intensity of MCM-2 expression in the epidermis of these samples were assessed by immunohistochemical SP method. Results The expression of MCM-2 was observed in basal and superbasal layer of epidermis in lesions of malignant and non-malignant hyperplasia, and only in epidermal basal layer in normal skin. A significant increment was observed in the density of MCM-2 positive cells in superbasal layer in malignant lesion compared with the non-malignant lesion. The epidermal expression level of MCM-2 in the non-malignant lesion was significantly lower than that in the malignant lesion, but higher than that in the normal skin （μ = -2.529, -3.705, respectively, both P < 0.05）; the same was true for the proportion of MCM-2-postive basal cells. Conclusions The expression of MCM-2 protein varies with the proliferation status of epidermal cells, and may serve as an objective marker for epidermal cell proliferation.