Decreased expression of the p63 related proteins beta-catenin, E-cadherin and EGFR in oral lichen planus.

Oral lichen planus (OLP) is a chronic inflammatory disease and although classified by WHO as a premalignant condition, the risk for transformation into squamous cell carcinoma of the head and neck (SCCHN) is a matter of great controversy. The p63 gene encodes six different proteins which are required for development of ectodermally derived tissues such as oral mucosa, salivary glands, teeth and skin. p63 is highly expressed in SCCHN whereas decreased expression is seen in OLP. beta-catenin, E-cadherin and epidermal growth factor receptor (EGFR) are p63 related proteins, and abnormalities in their expression suggested they are involved in development of squamous cell carcinoma of the head and neck (SCCHN). In this study we mapped the expression of these p63 related proteins in OLP and matched normal healthy controls. Results showed decreased expression of beta-catenin, E-cadherin and EGFR in the vast majority of OLP samples compared with the normal controls. This is the first comprehensive study mapping expression of several p63- and SCCHN-related proteins in tissue from patients with OLP. Results showed a mixed expression pattern with OLP variably resembling normal as well as tumour tissue. Based on our present and previous data it cannot be judged whether OLP lesions are at an increased risk of malignant development.