Expression of the serine protease DESC1 correlates directly with normal keratinocyte differentiation and inversely with head and neck squamous cell carcinoma progression

Background. As part of ongoing studies aimed at identifying the molecular events involved in head and neck squamous cell carcinoma progression, we recently isolated a novel serine protease, DESC1. This study was conducted to further characterize DESC1. Methods. Specimens of normal, dysplastic, and carcinomatous oropharyngeal mucosa (n = 31) were evaluated for DESC1 immunoreactivity using standard streptavidin‐biotin immunoperoxidase techniques. Between‐lesion stain intensity values were analyzed using multiple Wilcoxon tests. DESC1 expression was also evaluated in cultured human keratinocytes after induction of differentiation by calcium challenge, with subsequent real‐time reverse transcriptase‐polymerase chain reaction quantification. Results. DESC1 immunoreactivity decreased as lesions approached a malignant phenotype. Post hoc testing comparing the different lesion types and DESC1 staining values showed significance between “normal” and “carcinoma” (p = .0017) groups. Induction of normal keratinocyte differentiation by calcium challenge was accompanied by an increase in DESC1 expression (p = .002). Conclusions. These results suggest downregulation of DESC1 during squamous cell carcinoma progression and upregulation during normal epithelial differentiation. © 2005 Wiley Periodicals, Inc. Head Neck 28: 432–440, 2006