Expression of CLLD7 and CHC1L Proteins in Oral Epithelial Dysplasia in a Group of Thai Patients

Objectives: Previous study showed aberrant CLLD7 and CHC1L protein expression in oral squamous cell carcinoma (OSCC) compared to normal oral mucosa (NOM). This study aimed to evaluate the expression of these proteins in oral epithelial dysplasia (OED). Materials and Methods: Forty specimens of OED and 11 NOM were used. The expression of CLLD7 and CHC1L was determined by immunohistochemistry. In each case, at least 1000 cells were counted. Presence of nuclear, cytoplasmic, and/or membrane staining of CLLD7 and CHC1L were considered positive. Percentages of total positive cells and positive cells at different locations were recorded. SPSS version 18 was used to compare variation between groups with statistical significance at p<0.05. Results: No significant differences in the percentages of total positive cells of CLLD7 and CHC1L were found between NOM and all grades of OED. Nevertheless, there were significant differences in subcellular staining of these two proteins. In CLLD7, the nuclear staining of the moderate and the severe OED groups was significantly lower than that of the NOM group (p<0.05). The percentages of membrane staining of CHC1L in moderate and severe OED were significantly higher than that of NOM (p<0.001). In addition, the nuclear staining of CHC1L in each grade of OED was significantly lower than that of NOM (p<0.05). Conclusion: The subcellular mislocalization of CLLD7 and CHC1L in OED suggests that the expression of these potential tumor suppressor proteins might be dysregulated during the dysplastic process. The distinct membrane staining of CHC1L observed in OED but not in NOM is a useful characteristic that can be used to separate OED from NOM. Thus, CHC1L may be a good marker to assist in the diagnosis of OED.