Abstract: Objective To investigate the expression of aldehyde dehydrogenase 3B1 (ALDH3B1) in gastric cancer and explore its correlation with the pathological parameters and long-term prognosis of the patients. Methods We analyzed the clinical data of 101 patients who underwent radical gastrectomy for gastric cancer in our hospital between January, 2013 and November, 2016, and examined the expression of ALDH3B1 in paraffin-embedded samples of gastric cancer tissues and adjacent tissues from these cases by immunohistochemical staining. We evaluated the correlation between ALDH3B1 expressions and histopathological parameters and assessed the predictive value of ALDH3B1 expression for long-term survival of the patients. We also examined the effect of lentivirus-mediated interference and overexpression of ALDH3B1 on the malignant behaviors of MGC- 803 gastric cancer cells. Results The expressions of ALDH3B1 and Ki67 were significantly higher in gastric cancer tissues than in adjacent tissues (P<0.05). In gastric cancer patients, ALDH3B1 expression was positively correlated with peripheral blood CEA and CA19-9 levels (P<0.01). The proportion of patients with CEA ≥5 μg/L, CA19-9 ≥37 kU/L, T stage of 3- 4, and N stage of 2-3 was significantly greater in high ALDH3B1 expression group than in low expression group. Kaplan-Meier survival analysis showed that the 5-year survival rate was significantly lower in gastric cancer patients with high ALDH3B1 expressions (P<0.01). Univariate and Cox multiple regression analyses identified a high expression of ALDH3B1 (P<0.05, HR=0.231, 95% CI: 0.064-0.826), CEA≥5 μg/L (P<0.01, HR=4.478, 95% CI: 1.530-13.110), CA19-9≥37 kU/L (P<0.01, HR=3.877, 95% CI: 1.625-9.247), T stage of 3-4 (P<0.01, HR=4.953, 95% CI: 1.768-13.880), and N stage of 2-3 (P<0.05, HR=2.152, 95% CI: 1.152-4.022) as independent risk factors affecting 5-year survival after radical gastrectomy. The relative ALDH3B1 expression level, at the cut-off point of 4.66, showed a sensitivity of 76.47% and a specificity of 76% for predicting 5-year postoperative death (P<0.01). In the cell experiment, overexpression of ALDH3B1 obviously promoted the proliferation, migration and invasion of MGC-803 cells. Conclusion As an independent risk factor affecting 5-year survival after radical gastrectomy, ALDH3B1 is highly expressed in gastric cancer and correlated with pathological parameters of the tumor, and a high ALDH3B1 expression may promote proliferation, invasion and metastasis of gastric cancer cells.

Key words: gastric cancer; aldehyde dehydrogenase 3B1; pathology; survival analysis; risk factor analysis