Expression and Prognostic Value of MCM2 in type B thymomas

Abstract Background: Thymic epithelial tumor (TET) is the most common type of mediastinal malignancies. Currently, there is no reliable biomarker for predicting the prognosis of patients with TET. The purpose of the study was to find out a target gene, which may serve as a potential prognostic biomarker for TET patients. Methods: By mRNA microarray analysis of 30 specimens of fresh tumor tissue and peritumoral thymic tissue, the differentially expressed genes (DEGs) were screened out. The hub genes were identified from DEGs using protein-protein interaction (PPI). Survival analysis and enrichment analysis were performed to selected the target gene from hub genes. By establishing the validated cohort, we explored the association of the target gene expression with prognosis and clinicopathological characteristics. Results: The 734 DEGs were differentially expressed between thymoma and peritumoral thymic tissue. The 9 hub genes were identified from DEGs, in which minichromosome maintenance proteins 2 ( MCM2 ) was selected as the target gene. In the validated cohort, the expression of MCM2 in thymic epithelial cells was significantly associated with a prolonged progression-free survival (PFS) (HR=0.17; 95% confidence interval [CI]: 0.05-0.54; p =0.003), and it was also the independent risk factor of PFS in TETs (HR=0.26; 95% CI: 0.08-0.91; p =0.035). Further analyses showed that the expression of MCM2 was decreased from type B1 to B3 thymomas. Conclusions: MCM2 expression was the independent risk factor for TETs. The expression of MCM2 was significantly associated with a prolonged PFS, and it was decreased from type B1 to B3 thymomas. Therefore, MCM2 may be a favorable prognostic marker in type B thymomas.