Prognostic markers in salivary gland cancer and their impact on survival.

Abstract

The role of molecular markers in salivary gland carcinoma (SGC) is not well understood. We evaluated molecular marker expression and their prognostic value. Immunohistochemical analysis of 124 tumor specimens was performed to determine expression of androgen (AR), estrogen (ER), and progesterone (PR) receptors and epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), programmed death ligand 1 receptor (PD-L1), and PD-L1 in tumor-infiltrating mononuclear cell (TIMC). Survival outcomes (disease-free survival [DFS] and overall survival [OS]), pT and N classification, margin status, and treatment failure were assessed. Most patients (78; 62.9%) had early-stage SGC. AR positivity and EGFR positivity were detected in 21.0% and 78.6%, respectively, of tumors. AR positivity and PD-L1 negativity were associated with locally advanced disease. PD-L1-negativity was associated with higher recurrence (38.5% vs 0%; P < .001) and worse DFS. OS and DFS were worse in patients with AR+ or HER2+ disease. Several molecular markers-AR and HER2 positivity and PD-L1 negativity-were associated with worse clinical outcomes. Prospective, multi-institutional trials are needed to determine the prognostic value of these markers.