Aldehyde Dehydrogenase 1 Expression is Associated with Poor Prognosis in Patients with Esophageal Squamous Cell Carcinoma

Aldehyde dehydrogenase 1 (ALDH1) and CD44 act as important biomarkers in several solid tumors. However, few studies have examined the relationships between ALDH1 expression and the prognosis and clinical characteristics of esophageal squamous cell carcinoma (ESCC). This study was a retrospective case-control study and included 152 patients with ESCC. A total of 56 patients underwent surgery (OP group), 40 patients received neoadjuvant chemotherapy involving weekly docetaxel plus 5-fluorouracil and low-dose cisplatin (DFP therapy) prior to undergoing surgery (NAC group), and 56 patients received initial systemic DFP therapy (CT group). The ALDH1 and CD44 immunohistochemical expression levels of each tumor were evaluated and compared with the prognosis and clinical characteristics of the ESCC patients. In the OP and NAC groups, multivariate analysis found that ALDH1 was independently associated with postoperative recurrence and prognosis (OP group, P = 0.004 and 0.016, respectively; NAC group, P = 0.026 and 0.014, respectively). In addition, CD44 was found to be associated with postoperative recurrence in the OP group and prognosis in the NAC group (P = 0.024 and 0.047, respectively). Among the ALDH1-negative clinical stage II/III patients, the OP and NAC groups displayed better prognoses than the CT group (P < 0.001). However, among the ALDH1-positive clinical stage II/III patients, the OP and NAC groups displayed poorer prognoses than the CT group (P = 0.049). ALDH1 was found to be a predictor of postoperative recurrence and prognosis in ESCC, and CD44 might be a predictor of recurrence and prognosis. ALDH1 expression might affect the treatment strategy for ESCC.