Simple Cancer Stem Cell Markers Predict Neoadjuvant Chemotherapy Resistance of Esophageal Squamous Cell Carcinoma

Background/Aim: Cancer stem cells (CSCs) contribute to resistance against neoadjuvant chemotherapy (NAC) in esophageal squamous cell carcinoma (ESCC). We conducted a retrospective observational study for the relationship between the expression levels of CSC markers in biopsy specimens prior to 5-fluorouracil plus cisplatin (FP)-NAC and the pathological responses. Patients and Methods: We included 171 patients with ESCC who underwent the FP-NAC followed by radical resection. Biopsy specimens prior to the FP-NAC were obtained and immunochemically stained for CD44, CD133, and CD24. Results: The biopsy specimens of the non-responders had the CD44(high)/CD24(low) expression at high levels, which was found as an independent predictor of not only FP-NAC resistance but also poor overall survival by multivariate analyses. Conclusion: CD44(high)/CD24(low) expression in the biopsy specimens prior to FP-NAC may be a predictor of FP-NAC resistance and poor prognosis of ESCC patients.