R‑spondin family members as novel biomarkers and prognostic factors in lung cancer

The R-spondin (RSPO) family of secreted proteins consists of four members that have critical roles in embryonic development and organogenesis. However, the expression patterns and the exact roles of the individual RSPO family members in tumorigenesis and progression of lung cancer are unknown, particularly in non-small cell lung cancer, which accounts for 85% of all lung cancer cases. In the present study, data from the ONCOMINE database was used to compare the RNA expression levels of RSPOs in multiple different types of cancer with normal controls. The expression profiles of RSPOs in various types of cancer cell lines were subsequently compared based on data from the Broad Institute Cancer Cell Line Encyclopedia. Using the Kaplan-Meier plotter, the prognostic value of expression of the different RSPOs members was determined for different pathological subtypes of lung cancer. When compared with normal tissues, expression of RSPO1, RSPO2 and RSPO3 was significantly lower in patients with lung cancer. In the survival analysis, increased mRNA expression levels of RSPO1, RSPO2 and RSPO3 were associated with increased survival in patients with lung adenocarcinomas. These results suggest that RSPO1, RSPO2 and RSPO3 may serve as distinct biomarkers and prognostic factors in patients with lung cancer.