Upregulation of epidermal growth factor receptor 4 in oral leukoplakia

In the present study, we investigate the expression profile of the epidermal growth factor receptor family, which comprises EGFR/ErbB1, HER2/ErbB2, HER3/ErbB3 and HER4/ErbB4 in oral leukoplakia (LP). The expression of four epidermal growth factor receptor (EGFR) family genes and their ligands were measured in LP tissues from 14 patients and compared with levels in 10 patients with oral lichen planus (OLP) and normal oral mucosa (NOM) from 14 healthy donors by real-time polymerase chain reaction (PCR) and immunohistochemistry. Synchronous mRNA coexpression of ErbB1, ErbB2, ErbB3 and ErbB4 was detected in LP lesions. Out of the receptors, only ErbB4 mRNA and protein was more highly expressed in LP compared with NOM tissues. These were strongly expressed by epithelial keratinocytes in LP lesions, as shown by immunohistochemistry. Regarding the ligands, the mRNA of Neuregulin2 and 4 were more highly expressed in OLP compared with NOM tissues. Therefore, enhanced ErbB4 on the keratinocytes and synchronous modulation of EGFR family genes may contribute to the pathogenesis and carcinogenesis of LP. Oral disease: a new drug target for leukoplakia People with the condition known as leukoplakia, which causes thickened, white patches to form inside the mouth, express elevated levels of epidermal growth factor receptor (EGFR) 4, a signaling molecule that has been linked to cancer. The findings, reported by Yoshiki Hamada of Tsurumi University, Japan, and colleagues could explain one of the drivers of this precancerous dental disease and provide a new target for drug therapies. Hamada and his colleagues compared the expression profile of the four EGFR-family genes and their target ligands among 14 people with leukoplakia, 10 people with a separate mouth condition known as oral lichen planus and 14 healthy controls. They showed that only the fourth receptor, sometimes called HER4 or ErbB4, was overexpressed in people with leukoplakia along with two of its activating ligands, Neuregulin 2 and 4.