Immunohistochemical detection of "ex novo" HLA-DR in tumor cells determines clinical outcome in laryngeal cancer patients

Abstract

There are controversial results about the role of "ex novo" HLA-DR expression by tumor cells and its correlation with the oncological outcomes. Unfortunately, little is known about HLA-DR expression in laryngeal cancer tumor cells. The main purpose of this retrospective study is to strengthen the usefulness of studying "ex novo" HLA-DR expression on tumor cells from primary laryngeal squamous cell carcinoma (LSCC) patients and investigate its correlation with clinical outcome. We analyzed HLA-DR expression by immunohistochemical analysis in 56 patients with LSCC. The "ex novo" HLA-DR expression on laryngeal cancer tumor cells, assessing non-neoplastic LSCC - adjacent tissue, and the association of HLA-DR expression (HLA-DR+) with clinical outcomes were investigated. HLA-DR+ tumor cells were detected in 18/56 LSCC patients (32.1%). All specimens of non-neoplastic laryngeal carcinoma-adjacent tissue resulted HLA-DR negative (HLA-DR-). A statistically significant association was observed between HLA-DR + and well differentiated tumors (G1) (p<0.001). The Kaplan-Meier method showed how HLA-DR+ is significantly associated with both a better disease specific survival (HLA-DR+=100% vs. HLA-DR-=77.4%; p=0.047) and a better relapse free survival (HLA-DR+=100% vs. HLA-DR-=72.3%; p=0.021). Cox regression univariate analysis for death of disease confirmed a higher HR for HLA-DR absence on the surface of epithelial tumor cell [HR:37.489; 95% CI:0.750-18730.776; p=0.253] and for high-grade (G3) tumors [HR:18.601; 95% CI:3.613-95.764; p<0.0001]. Our results confirm that MHC class II HLA-DR expression is activated in a sub-set of LSCC patients. Evaluation of HLA-DR expression in LSCC could be useful for prognosis and future approaches towards personalized therapy.

Keywords: HLA-DR; MHC II; immunohistochemistry; laryngeal squamous cell carcinoma; personalized medicine; tumor immunology.