Cancer stem cell marker ALDH1 and CD44 expression: Independent predictors of survival outcome in oral cancer patients

Oral squamous cell carcinoma (OSCC) significantly impacts global cancer incidence, with cancer stem cells (CSCs) such as ALDH1 and CD44 promoting tumor growth and self-renewal. This study examines the correlation between these CSC markers ALDH1 and CD44 with clinicopathological factors and survival outcomes in OSCC patients.

The expression of cancer markers in 161 tumor tissue blocks was assessed through Immunohistochemistry (IHC). Fluorescence-activated cell sorting (FACS) was used to identify the immunoexpression of CD44 and ALDH1 in primary oral cancer cell lines derived from patients. The five-year survival outcome was calculated by Kaplan Meier (KM).

Our five-year study found significant associations between CSC markers and clinicopathological factors in OSCC patients. ALDH1 was linked to lymph node metastasis (P = 0.029), recurrence (P < 0.001), tumor histology (P < 0.001), and higher tumor staging (P = 0.008). Conversely, CD44 correlated with non-tobacoo chewing (P = 0.023), poorly differentiated tumor (P < 0.001), recurrence (P < 0.001) and mortality (P < 0.001). Patients with ALDH1-positive tumors had lower DFS (46.37 vs 62.92), while CD44-positive tumors had lower OS (58.98 vs 63.54). Univariate and multivariate analyses showed high ALDH1 expression associated with lower DFS (HR = 3.35, 95% CI = 1.93-5.82, P < 0.001), and high CD44 levels with lower OS (HR = 2.02, 95% CI = 1.11-3.66, P = 0.021).

This study aimed to identify ALDH1 and CD44 expressions as cancer stem cell markers and independent predictors of lower five-year disease-free survival (DFS) and overall survival (OS), respectively. These markers effectively predict oral cancer prognosis and treatment response, enabling clinicians to improve patient outcomes.