Application of serum anti‑ENO1 and anti‑SSNA1 antibody biomarkers in predicting the prognosis of gastric cancer

Given the high malignancy of advanced gastric cancer, the identification of biomarkers for the diagnosis and prognosis prediction of advanced gastric cancer is of importance. The present study conducted the serological identification of antigens by recombinant cDNA expression cloning and determined enolase 1 (ENO1) and Sjögren syndrome nuclear autoantigen 1 (SSNA1) as tumor antigens recognized by serum immunoglobulin G (IgG) antibodies in patients with gastric cancer. The clinicopathological significance of preoperative autoantibodies were assessed, namely serum anti-ENO1 antibodies (s-ENO1-Abs) and serum anti-SSNA1 antibodies (s-SSNA-Abs), in the sera of 166 patients with gastric cancer who underwent radical surgery and 96 healthy donors. The s-ENO1-Ab and s-SSNA-Ab titer levels were significantly increased in patients with gastric cancer compared with that in healthy donors (P<0.01). Areas under the receiver operating characteristic curves of s-ENO1-Ab and s-SSNA1-Ab were 0.656 and 0.607, respectively. None of the clinicopathological factors, such as sex, age, histological type, tumor size, tumor depth, nodal status, cytology, peritoneal dissemination and stage demonstrated association with the s-ENO1-Ab or s-SSNA1-Ab titer levels. High s-ENO1-Ab and s-SSNA1-Ab titer levels were associated with improved overall survival, but the differences were not statistically significant. According to the Human Protein Atlas dataset, high mRNA expression levels of ENO1 and SSNA1 showed a trend towards shorter overall survival, while low expression levels showed a trend towards longer overall survival (ENO1: P=0.07, SSNA1: P<0.05). Combination analysis indicated that the s-ENO1-Ab-positive (+)/carcinoembryonic antigen (CEA)-negative (-) group demonstrated a significantly improved prognosis compared with that of the s-ENO1-Ab(-)/CEA(+) group (P<0.01), while a comparison of the s-SSNA1-Ab(+)/CEA(-) group with the s-SSNA1-Ab(-)/CEA(+) group also demonstrated a significant improvement in prognosis (P<0.01). Thus, s-ENO1-Abs and s-SSNA-Abs may be useful biomarkers for predicting gastric cancer prognosis, providing future research directions for novel approaches to target and treat gastric cancer.