IMMUNOHISTOCHEMICAL ANALYSIS OF HUMAN LEUKOCYTE ANTIGEN-DR (HLA-DR) IN LIP CARCINOGENESIS

Abstract

Objective To evaluate the immunoexpression of human leukocyte antigen-DR (HLA-DR) in actinic cheilitis (AC) and lower-lip squamous cell carcinomas (LLSCCs), and to correlate the findings with clinicopathologic parameters (tumor size and extent, regional lymph node metastasis, clinical stage, risk of malignant transformation for AC and histopathologic grade of malignancy for LLSCCs). Study Design The percentage of HLA-DR–positive cells in the epithelial component of 24 cases of AC and 48 LLSCCs (24 with regional nodal metastasis and 24 without metastasis) were assessed. The results were analyzed statistically using the nonparametric Mann-Whitney test. Results Only 5 (20.8%) cases of AC (2 low risk and 3 high risk) exhibited expression of HLA-DR, with a very low mean percentage of immunopositivity. Most LLSCCs (97.7%) presented with expression of HLA-DR, with a relatively high mean of immunopositivity. The percentage of HLA-DR–positive cells tended to be higher in tumors with regional metastasis, and tumors in advanced clinical stages (P > .05). There was a tendency for higher expression of HLA-DR in low-grade LLSCCs, and in highly or moderately keratinized tumors (P > .05). Conclusions The results suggest a potential role for HLA-DR in lip carcinogenesis, particularly in the progression of LLSCCs. The expression of this protein can be related to the degree of cell differentiation in these tumors.