Comparison of matrix metalloproteinase-1 expression in tumor-associated and nontumor-associated skin in patients with basal cell carcinoma

Basal cell carcinomas (BCC) produce large varieties of matrix metalloproteinases (MMPs). MMP induction occurs as a consequence of acute ultraviolet exposure, and may be some of the enhanced enzyme expression in tumor-associated skin reflects a response to solar radiation rather than an effect of the tumor itself. Of the MMP family, MMP-1 (collagenase-1) is the most abundantly expressed in various skin conditions. The aim were to compare MMP-1 expression using immunohistochemistry in BCC different areas (tumoral, peritumoral, and safety margin) with nontumor associated, sun-exposed skin and to determine the exact role of MMP-1 in the pathogenesis of BCC and its invasiveness. This study included 24 BCC patients, who also represented the controls by taking punch biopsies from normal skin on the dorsa of their hands (as sun-exposed areas). Immunohistochemical assessment of MMP-1 in lesional skin biopsy and control biopsies was carried out. MMP-1 expression in peritumoral area of BCC was significantly higher than the tumoral area, safety margin, and control (P 60 years) showed greater MMP-1 expression compared to their counterparts in younger age group (P<0.05). Patients with outdoor occupations demonstrated greater expression of MMP-1 in control areas compared with control skin from patients not excessively sun exposed (P<0.05). A significantly greater MMP-1 expression was found in peritumoral areas of undifferentiated BCC (P<0.05) compared with differentiated BCC. MMP-1 may have a role in the propagation of BCC, mainly through the stromal cells (peritumoral area) surrounding the tumor nests. This effect is because of the presence of the tumor and not exclusively dependent on sunlight exposure.