Identification of molecular biomarkers for the diagnosis of gastric cancer and lymph-node metastasis.

BACKGROUND AND OBJECTIVE

Biomarkers are important tools for prompt diagnosis of cancer. This study aimed to identify reliable biomarkers for clinical applications in the diagnosis of gastric cancer and lymph-node (LN) metastasis.

METHODS

Between 1 December 2014 and 31 December 2015, we prospectively collected samples of gastric-cancer tissues, corresponding matched-pair normal gastric mucosa, and their peri-gastric metastatic and non-metastatic LNs to identify quantitatively reliable genes using quantitative real-time polymerase chain reaction. Relative quantity (RQ) was used to calculate the mRNA expression levels of our target genes. Statistics were calculated using one-way analysis of variance (ANOVA) and Tukey's multiple comparison test. Analytical graphs were plotted using GraphPad Prism.

RESULTS

Of nine assessed genes, the mRNA levels of inhibin beta A () and secreted phosphoprotein 1 () were most consistently highly expressed in tumor tissues by 15.4- and 15.6-fold, respectively, as compared with normal tissues ( < 0.001), with 91.3% sensitivity and 95.7% specificity (receiver operating characteristic [ROC] curve area = 0.974) for the former and 82.6% sensitivity and 87.0% specificity (ROC curve area = 0.924) for the latter. Further analysis revealed no differentiating significance of mRNA expression between metastatic and non-metastatic LNs ( = 0.470). In contrast, the mRNA level was up-regulated 4.1-fold in metastatic LNs ( < 0.001), with 80.0% sensitivity and 81.5% specificity (ROC curve area = 0.857), and was also able to successfully differentiate between more severe disease conditions, T3 and T4 ( = 0.003), M0 and M1 ( = 0.043) and different histological variants (intestinal type vs diffuse type,  = 0.019).

CONCLUSIONS

Our results showed that was the most optimally reliable biomarker for diagnosing gastric cancer and LN metastasis.