Actually, several reports revealed that the expression of MMP-9 on tumors was correlated with the progression or prognosis of several skin tumors such as malignant melanoma, squamous cell carcinoma, basal cell carcinoma, mycosis fungoides, extramammary Paget's disease, and angiosarcoma [7, 9, 14–19]. The gene discussed is MMP9; the disease is basal cell carcinoma.