Prognostic significance of SPARC expression in non-small cell lung cancer: A meta-analysis and bioinformatics...

The aim of the present study was to elucidate the significance of secreted protein acidic and cysteine rich (SPARC) expression in non-small cell lung cancer (NSCLC) in terms of clinicopathology, immune-cell infiltration and survival prognosis. A meta-analysis and bioinformatics analysis were performed using studies retrieved with PubMed, Web of Science, Wanfang Data and the Chinese National Knowledge Infrastructure databases. The meta-analysis suggested that, compared with normal tissues, SPARC expression was elevated in NSCLC tissues. The expression of SPARC was not significantly associated with TNM stage and lymph-node metastasis, and was positively associated with patient gender. Regarding the differential expression of SPARC and the relationship between expression levels and survival, the Oncomine database was consulted and Kaplan-Meier curves were drawn. It was indicated that SPARC mRNA expression levels were higher in NSCLC tissues than in normal tissues. Low expression of SPARC mRNA was negatively associated with overall survival, first progression survival and post-progression survival of patients. Further exploration of the relationship between SPARC expression and survival by univariate analysis indicated that TNM stage, lymph node metastasis, distant metastasis and depth of infiltration of lung cancer were negatively associated with patient prognosis. Cox multifactorial analysis suggested that SPARC expression levels and TNM stage were risk factors significantly affecting the prognosis of patients with NSCLC. Analysis with the GEPIA and UALCAN databases further indicated that the mRNA expression level of SPARC in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) was higher than that in normal lung tissue, and the SPARC expression levels were affected by factors such as the TNM stage of lung cancer. A lower the level of SPARC mRNA expression was associated with a better relative survival prognosis of patients. In the Human Protein Atlas database, the expression level of SPARC protein was higher in LUAD and LUSC than in normal lung tissue. In the Timer database, the expression level of SPARC was closely linked to immune cells related to the occurrence of lung cancer, and the degree of immune-cell infiltration and SPARC protein expression were closely related to the prognosis of patients with lung cancer. Immune cells were indicated to exhibit significant inhibition of DNA proliferation mutation mechanisms in lung cancer (P<0.05). In summary, SPARC expression may be used as a valuable indicator of prognosis in patients with NSCLC, which may provide new approaches for preventative treatment.