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

Introduction: 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. Materials and Methods: 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). Results: 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). Conclusion: 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.