Role of Sp1 expression in gastric cancer: A meta-analysis and bioinformatics analysis

Sp1 (specificity protein 1) is an important transcription factor that regulates multiple cancer-related genes. A number of published studies have explored the relationship between Sp1 expression and prognosis in gastric cancer. Therefore, a deeper level of understanding is required into the molecular biological mechanism of gastric cancer. Finding new tumor biomarkers for the accurate prediction of occurrence, recurrence and metastasis of gastric cancer are of great significance. The present study uses a systematic meta-analysis and bioinformatics analysis to acquire evidence for a prognosis marker based on Sp1 expression in gastric cancer. A literature search was performed using PubMed and China National Knowledge Infrastructure on 8th June, 2018. A total of 13 studies were included in the meta-analysis. The meta-analysis showed that the expression of Sp1 was significantly higher in gastric cancer tissue, compared with that of normal mucosa [odds ratio (OR), -0.53; 95% CI, -0.62-0.44; P<0.0001] and dysplasia (OR, 0.24; 95% CI, 0.13-0.44; P<0.0001). A positive association was found Sp1 expression and depth of invasion (OR, 0.31; 95% CI, 0.11-0.86), lymph node metastasis (OR, 0.36; 95% CI, 0.22-0.59), TNM staging of gastric cancer (OR, 0.43; 95% CI, 0.24-0.79) and Lauren's classification (OR, 0.83; 95% CI, 0.51-1.36), but not with sex or tumor differentiation (OR, 1.34; 95% CI, 0.95-1.88). According to the Oncomine database, Sp1 mRNA expression is significantly higher in gastric cancer tissues compared with that in normal tissues (P<0.05), including that of intestinal, diffuse and mixed-type gastric carcinomas (P<0.05). Kaplan-Meier plots show that the expression of Sp1 mRNA is negatively associated with overall and progression-free survival rates of patients with gastric cancer, even when stratified according to expression level (P<0.05). The selected prediction parameter is overall survival or progressive-free survival rate. The expression level of Sp1 was divided into high expression group and low expression group according to the best cut off value provided on the Kaplan-Meier plotter. However, Sp1 protein expression is upregulated in gastric cancer tissues compared with normal tissues and is positively associated with depth of invasion and TNM stage of gastric cancer. The high protein expression of Sp1 might make it a good potential marker for the prognosis of patients with gastric cancer.