CST6 and skin squamous cell carcinoma: Conversely to benign hyperplasia as observed during psoriasis vulgaris, a unique cancer-specific gene expression signature was identified for human cutaneous squamous cell carcinoma (cSCC) associated with a gene downregulation of granzyme B, and a differential gene upregulation (fold change > 3) of matrix metalloproteinase MMP-1, kallikrein 7, CatV and cystatin M/E [105].