Update on the Association of CD44 Expression with Esophageal Squamous Cell Carcinoma Invasion

Background Esophageal cancer (EC) is an aggressive gastrointestinal tumor necessitating novel prognostic, diagnostic, and therapeutic strategies. It is essential to identify important markers for diagnosing malignancy and predicting outcomes. Understanding gene functions in signaling pathways and early cancer detection are vital for reducing EC mortality. CD44 upregulation is linked to cancer stem cells (CSC), metastasis, poor prognosis, and treatment response. CD44v6, a variant of CD44, plays a pivotal role in tumor invasion and metastasis by influencing the extracellular matrix, promoting cell motility, and suppressing cancer cell apoptosis. Methods This study investigated CD44v6 expression in tumor and tumor-free tissues of the esophagus in 50 esophageal squamous cells carcinomas (ESCC) patients using real-time PCR. The aim was to assess its prognostic value and its correlation with tumor invasion. Results Significant overexpression of CD44v6 mRNA was detected in 9 out of 50 tumor specimens (18%, p = 0.0001). CD44v6 expression showed an inverse correlation with tumor cell metastasis to lymph nodes (p = 0.047). Among the 21 patients with lymph node metastasis, 5 (23%) exhibited CD44v6 overexpression. Additionally, CD44v6 expression was linked to the tumor stage (p = 0.008). Specifically, 2 out of 9 patients with stage I tumors (22.2%), 4 out of 9 with stage II tumors (44.4%), and 3 out of 9 with stage III tumors (33.3%) showed CD44v6 overexpression. Conclusions Our findings suggest that lower CD44v6 expression at the RNA level correlates with increased tumor invasion and more advanced stages in ESCC.