GC has long been one of the world’s major cancers and remains one of the major causes of malignant disease morbidity and mortality[16]. Evidence have proved that SPARC has a crucial function in the process of tumorigenesis, but the bioinformation according to the TCGA data in GC are still firstly performed in this study.
According to our study, SPARC expression was significantly higher in the GC tissue samples compared to the control samples or the paired adjunct samples. Which suggested that the up-regulation of SPARC expression may be related to the development of GC.
Moreover, the clinical diagnosis and prognostic value of the SPARC expression were examined in our study of GC patients. At the beginning, we found that SPARC expression was significantly associated with clinical grade and T classification. Second, Kaplan–Meier curves for OS revealed that high expression of SPARC was associated with poor outcomes in GC patients. The area under the ROC curve showed the up-expression of SPARC in value of diagnosis. Further, univariate logistic analysis indicated the SPARC expression had relation with T classification. Univariate and multivariate Cox analysis showed the SPARC expression may be a potential independent marker for poor prognosis in GC patients. The multivariate Cox analysis revealed age was an independent risk factor or OS in GC patient. In general, these findings suggested that high expression of SPARC could indicate a factor of diagnosis and poor prognosis for GC patients. Which also might be a pivotal target gene involved in the process of GC cell growth and metastasis.
In this study, we observe that SPARC high expression phenotype was associated with TGF beta signaling pathway, pathways in cancer, Wnt signaling pathway, Mitogen-activated protein kinase (MAPK) signaling pathway, focal adhesion, cell adhesion molecules cams, melanogenesis and small cell lung cancer. TGF beta signaling pathway is instrumental in mammalian development which has pivotal role in many mechanisms of breast cancer[17], lung cancer[18] and other cancer[19–21]. Wnt signaling pathway is required for adult tissue maintenance, and perturbations in Wnt signaling promote human cancer[22, 23].MAPK signaling pathway activated during the differentiation of myogenic cell lines[24]. Which is essential for human melanoma cells[25] and prostate cancer[26].Focal adhesion-dependent activation of these pathways has been involved in a diverse array of cellular processes and was a potential target in cancer therapy[27, 28].
However, prediction of protein expression according to mRNA was useful but far from perfect[29].In this report, the correlation between SPARC mRNA expression and SPARC protein expression has not been verified. We will conduct further research through experiments and local clinical information in the future.