Expression of the human homolog of discs, large homolog 1 (Drosophila) in normal epithelium, nodule, papilloma and invasive squamous cell carcinoma of larynx

Background and aim: The discs large 1 of Drosophila (DLG1) is a cell junction-localized protein that is required for the maintenance of cyto-architectural stability and alteration of DLG1 may be related to development of epithelial neoplasm. Methods: To determine DLG1 expression in human papillomavirus-related carcinogenesis, DLG1 expression in normal larynx (NL), laryngeal nodule (LN), laryngeal papilloma (LP), and invasive squamous cell carcinoma of larynx (SQCC) was investigated using immunohistochemistry. Results: In LN, the expression pattern of DLG1 was similar to NL showing cytoplasmic expression of basal and suprabasal cells except suprabasal membranous staining, which is observed in NL. In regard to basal cell expression, unlikely NL and LN, and the basal cells of most LPs did not express DLG1. In SQCC, the cancer cells of surface area showed strong cytoplasmic and membranous staining patterns of DLG1 in most SQCCs, whereas cells of deep invasive edge (IE) demonstrated weak cytoplasmic patterns without membranous staining. This expression pattern of DLG1 was similar to that of E-cadherin. Conclusions: Weak expression of DLG1 in IE of SQCC with a pattern similar to E-cadherin suggests that the perturbation of DLG1 as cell junction-localized cyto-architectural protein may be associated with progression of invasiveness.