Combined CD44, c-MET, and EGFR expression in p16-positive and p16-negative head and neck squamous cell carcinomas

To examine the association between CD44 and c-MET expression in relation to p16 and EGFR in patients with head and neck squamous cell carcinoma (HNSCC).

Immunohistochemical staining of CD44, p16, EGFR, and c-MET was performed on 105 locally advanced HNSCC patients treated with chemoradiation. CD44 expression was correlated with c-MET, EGFR, and p16, locoregional control (LRC), distant metastases (DM), disease-free survival (DFS) and overall survival (OS).

High CD44 expression was present in 33% of patients and was associated with non-oropharynx primaries (P < 0.001), high c-MET expression (P < 0.001), p16-negative (P < 0.001) and EGFR-positive tumors (P < 0.001). Fifty-seven percent of CD44 high expressing tumors had high c-MET expression compared to 21% of CD44 low expressing tumors (P < 0.001). High CD44 expression predicted for worse LRC (HR: 2.44; 95% CI: 1.16-5.13; P = 0.018), DFS (HR: 2.61; 95% CI: 1.46-4.67; P = 0.001), and OS (HR: 2.52; 95% CI: 1.30-4.92; P = 0.007) but not DM (P = 0.57) on univariate analysis. Patients with both high CD44 and c-MET expression had a poor prognosis with a 2-year DFS of 30% compared to 70% in the rest of the cohort (P = 0.003). On multivariable analysis, after adjusting for site, T-stage, smoking history, and EGFR status, high c-MET (P = 0.039) and negative p16 status (P = 0.034) predicted for worse DFS, while high CD44 expression did not (P = 0.43).

High CD44 expression is associated with high c-MET expression, p16-negative tumors, and EGFR-positive tumors. The combination of these markers predicts for poor prognosis in HNSCC patients treated with chemoradiation.