Role of SPP1 in the diagnosis of gastrointestinal cancer.

Recently, the incidence rate of digestive system tumors has increased in China and these tumors occur in a younger population. The present study aimed to determine the expression levels and potential clinical value of secreted phosphoprotein 1 (SPP1) in gastrointestinal cancer. The microarray datasets GSE104836, GSE189830 and GSE103236, obtained from the gene expression omnibus database, were analyzed to determine differentially expressed genes in patients with colorectal cancer (CRC), gastric cancer (GC) and esophageal cancer (EC). A total of 42 patients with CRC, GC or EC and 21 healthy controls were recruited to obtain blood and tissues samples. SPP1 expression levels were detected using reverse transcription-quantitative PCR. Moreover, levels of significance of SPP1 in patients with CRC, GC and EC were analyzed using receiver operating characteristic analysis. Potential correlations between SPP1 and carcinoembryonic antigen (CEA) were assessed using Pearson's correlation coefficient. SPP1 was significantly upregulated in the serum, plasma and tissue of patients with CRC, GC or EC. In addition, the area under the curve of SPP1 was >0.5 in the plasma, serum and cancer tissue of patients with early and late CRC, GC or EC. The present study further demonstrated that the specificity and sensitivity of SPP1 was higher in patients with late CRC, GC or EC compared with patients with early CRC, GC or EC. Moreover, SPP1 and CEA were significantly positively correlated in serum of patients with CRC, GC or EC. In conclusion, the current study demonstrated that SPP1 exhibited significant diagnostic value for gastrointestinal tumors, which suggested that SPP1 may exhibit potential as a diagnostic marker of CRC, GC and EC. The present study provided a novel theoretical basis for the role of SPP1 as a diagnostic marker of digestive system tumors.