Objective The purpose of this studywas to investigate the transcription and expression levels of human leukocyte antigen-DR at different stages of oral squamous cell carcinomas.Methods The specific monoclonal antibody andβ-locus specific oli- gonucleotide probes of human leukocyte antigen-DR were employed in this study. A total of 32 primary oral squamous cell carcino- mas, 15 metastatic focuses and 26 histologically normal oral epithelia, were detected forthe presence of the human leukocyte antigen- DR molecule by using immunohistochemistry and in situ hybridization.Results The human leukocyte antigen-DR expression of the primary focuses was significantly higher than that of the normal epithelia (P
