Reduction of syndecan‐1 expression during lip carcinogenesis

Abstract

Actinic cheilitis (AC) is an oral pre-cancerous lesion that sometimes develops into lip squamous cell carcinoma (SCC). Syndecan-1, a transmembrane heparan sulfate proteoglycan, modulates cell-proliferation, adhesion, migration and angiogenesis. Malignant epithelial cells often down-regulate their own syndecan-1 production, and are capable of inducing aberrant syndecan-1 expression in stromal cells. The aim of this study was to evaluate the variations in syndecan-1 expression during lip carcinogenesis, in normal lip (NL), AC and well-differentiated lip SCC. Biopsies of NL vermillion (n = 19), AC (n = 23) and lip SCC (n = 24) were stained immunohistochemically for syndecan-1. Syndecan-1 expression was significantly reduced in AC and lip SCC as compared to NL (P < 0.05), with a significant reduction in lip SCC as compared to AC (P < 0.0001). In lip SCC lesions, syndecan-1 expression at the epithelium overlying the tumor was increased when compared to the tumor itself (P < 0.03), but was significantly reduced as compared to AC and NL (P < 0.001). The results showed that epithelial syndecan-1 expression is reduced as lip carcinogenesis progresses (NL>AC>lip SCC), suggesting that syndecan-1 could be a useful marker of malignant transformation in the lip.