Immunohistochemical expression of MCM2 in nonmelanoma epithelial skin cancers.

Cutaneous basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) represent 45.5% and 37.02%, respectively, of total malignant skin cancer according to the latest registry of Egyptian National Cancer Institute. Minichromosome maintenance (MCM) proteins are essential replication initiation factors. The current study examined the immunohistochemical expression of MCM2 in normal skin (10 cases), some proliferative skin lesions (6 psoriasis, 2 keratoacanthoma, and 2 seborrheic keratosis), and nonmelanoma epithelial skin cancers (20 BCC and 21 SCC). MCM2 was expressed in basal layer of normal epidermis and upregulated in proliferative skin lesions and nonmelanoma epithelial skin cancers without significant differences between the latter groups (P > 0.05). Mean and median values of MCM2 percentage of expression in BCC were higher than that of SCC (P = 0.004). MCM2 promotes proliferative capacity of the cells manifested by its expression in basal layer of epidermis, hyperproliferative skin lesions, and malignant cutaneous tumors. Proliferative capacity of BCC may be higher than SCC and this does not necessarily reflect aggressive behavior.