Calcyphosine (CAPS), a calcium-binding protein, has been identified as a potential diagnostic and prognostic biomarker in several human carcinomas. However, little is known about CAPS in esophageal squamous cell carcinoma (ESCC). The present study aimed to investigate the expression levels of CAPS in ESCC tissues and evaluate its clinicopathological significance. Reverse transcription-quantitative polymerase chain reaction and immunohistochemical staining were conducted to detect the expression of CAPS in ESCC tissues and adjacent non-cancerous tissues. ESCC samples exhibited higher levels of CAPS mRNA than paired non-cancerous samples (P=0.0015), and the mRNA level of CAPS was positively associated with histological grade (P=0.0013) and tumor invasion depth (P=0.0206). In addition, Kaplan-Meier survival analysis revealed that patients with high CAPS expression experienced significantly shorter 5-year overall survival times than those with low CAPS expression (P=0.0112). Multivariate analysis demonstrated that CAPS protein expression was an independent prognostic biomarker for patients with ESCC. In conclusion, the findings of the present study demonstrated that CAPS may represent a novel diagnostic indicator and an independent prognostic biomarker in ESCC.
Keywords: calcium-binding protein; calcyphosine; esophageal squamous cell carcinoma; prognosis.