CD44 related stemness maneuvers oral squamous cell carcinoma biology

Introduction: Despite the commendable advancements in oral squamous cell carcinoma (OSCC) diagnostics and therapeutics, it remains a considerable medical challenge. Recent evidence suggests that small populations of stem-like cancer cells are responsible for tumor initiation, progression and metastasis. These cancer stem cells (CSCs) have been identified and characterized in various types of cancers, including OSCCs. CSC hypothesis has been supported by the expression of CD44, CD133, ALDH1 and ABCG2. Amongst them, CD44 (a transmembrane glycoprotein), is the most reported CSC marker in OSCCs. The increasing incidence of OSCC combined with its poor survival rates motivates a need for research into the expression of adhesion molecules and may play a pivotal role in studying tumor biology related to invasion and distant metastasis. Objective: To quantify the expression of CD44 in the different grades of OSCC and to correlate the expression of CD44 with clinicopathological parameters. Method: A total of 20 formalin-fixed paraffin-embedded tissues of OSCC were retrieved from department archives. Immunohistochemical staining was performed using anti-CD44 antibody (Biogenex). The expression was assessed semi-quantitatively in varying histopathological grades of OSCC and were correlated with tumor, node, metastasis (TNM) staging which were obtained from the department records. The results were statistically evaluated. Result: Overexpression of CD44 was detected in 48% of well-differentiated OSCCs followed by a linear decrease in moderately differentiated and poorly differentiated OSCCs and the expression correlated with the tumor size (T) in 23% cases and with lymph node metastases (N) in 42% of cases (P =0.05). Conclusion: The results of the present study suggested an altered expression of CD44 in OSCC. This depicts an association of CD44 with tumor aggressiveness and Epithelial Mesenchymal Transition (EMT) related to loss of cell adhesion in a subset of OSCC-clearly stating tumor cell stemness as a key factor in malignant potential of OSCC.