Abstract
AIM: In the present study, we investigated the relationship between the expressions of two cancer testis antigens (CTA), LY6K (lymphocyte antigen 6 complex locus K) and CDCA1 (cell division cycle associated 1), in esophageal squamous cell carcinoma (ESCC) tumors and the long-term outcomes of patients with ESCC to clarify the clinical significance of LY6K and CDCA1 expression in ESCC tumors. METHODS: A total of 175 patients with thoracic ESCC who had undergone a thoracic esophagectomy with three-field lymphadenectomy without neoadjuvant therapy were retrospectively reviewed in this study. LY6K and CDCA1 expressions were evaluated in tumor tissues using immunohistochemical (IH) staining. RESULTS: Median patient age was 63 years; 159 patients (90.9%) were men. Ninety-four patients (55.3%) were LY6K-positive, and 85 patients (48.6%) were CDCA1-positive. The LY6K-positive group had a significantly worse overall survival (OS) than the LY6K-negative group (P = 0.012), and the CDCA1-positive group had a significantly worse OS than the CDCA1-negative group (P = 0.010). A multivariate analysis suggested that pathological N stage, venous invasion, LK6Y-positive and CDCA1-positive were independent prognostic factors. The patients were classified into four groups according to the staining pattern combinations of the two CTA. The LY6K-positive and CDCA1-positive group was found to have a significantly poorer outcome than the other groups. CONCLUSION: ESCC patients with a combination of LY6K and CDCA1 expression in their tumor tissues had a worse prognosis than all the other ESCC patients and it was an independent factor associated with prognosis for patients with ESCC.