Apolipoprotein C1 (APOC1) as a novel diagnostic and prognostic biomarker for gastric cancer

Background: Gastric cancer (GC) is a common malignant cancer in the worldwide, especially in China. Patients with GC have poor prognosis, which is mainly due to lack of early diagnosis. Up to now, there is no good biomarker to detect GC at early stage. Apolipoprotein C1 (APOC1), a component of both triglyceriderich lipoproteins and high-density lipoproteins, is reported to be involved in numerous biological processes. Methods: Expression of APOC1 mRNA was analyzed by in silicon assay. Concentration of APOC1 in serum was measured by ELISA assay. Expression of APOC1 protein in GC tissue array was checked by immunohistochemistry. Results: It was firstly found that concentration of APOC1 in serum was significantly higher in GC than that in control. Expression of APOC1 protein was also higher in GC than that in adjacent issues of GC and normal tissues using tissues array by immunohistochemistry. In addition, the expression of APOC1 is significantly associated with clinical stage (P=0.011), tumor classification (P=0.010), as well as with the lymph node metastasis (P=0.048). Area under the curve (AUC) of receiver operating characteristic (ROC) curve of APOC1 was 0.803. Furthermore, elevated APOC1 expression in GC was found to be correlated with decreased overall survival (P=0.00214). Conclusions: All these results suggested that APOC1 might be a potential serum biomarker to diagnose GC and a potential prognostic marker for GC.