OBJECTIVEThe aim of this study was to investigate the mRNA expression levels of human leukocyte antigen Class I at different progressive stages of human oral squamous cell carcinomas.

METHODSThe expression of mRNA of human leukocyte antigen--B/C was detected in 23 primary tumors, 10 metastatic focuses and 11 histological normal oral epithelia using in situ hybridization method with a digoxigenin--labeled DNA probe. The probe was human leukocyte antigen--B/C locus specific.

RESULTSThe hybridization signals were present in the cytoplasm of either normal epithelia or tumor cells. The integrated optical density values of the hybridization signals were detected with the aid of an image analysis system. The results showed that the average integrated optical density values of the primary tumors were statistically lower than the normal oral epithelia (P < 0.05), but there was no significant difference between metastatic tumors and the primary tumors or the normal epithelia. The integrated optical density values measured in the metastatic tumors also did not show statistically differences compared with the primary tumors of the same patients.

CONCLUSIONImpaired regulation of human leukocyte antigen--B/C transcription could occur but might not be directly associated with metastasis of oral squamous cell carcinomas.