Common and differentially expressed long noncoding RNAs for the characterization of high and low grade bladder cancer

Our study aimed to explore long non-coding RNAs (lncRNAs) contributing to the development of bladder cancer, as well as to identify more critical DEGs and lncRNAs that would characterize low- and high-grade bladder cancer. The microarray data of GSE55433 was downloaded from Gene Expression Omnibus database, including 57 urothelial cancer samples (23 low-grade NMI, 14 high-grade NMI and 20 invasive tumors) and 26 normal controls. The differentially expressed genes (DEGs) and differentially expressed lncRNAs were identified in 3 groups (low-grade NMI vs. normal, high-grade NMI vs. normal and invasive UC vs. normal). Functional enrichment analysis was performed upon the DEGs in different groups. Besides, protein-protein interaction (PPI) network was constructed based on common DEGs and remaining DEGs in each group. Co-expression analysis was performed to identify the co-expressed DEG-lncRNAs pairs. Different number of DEGs and differentially expressed lncRNAs were respectively identified from those 3 groups. NONHSAG013805 (down-regulated) and NONHSAG009271 (down-regulated) were common lncRNAs. NONHSAG013805 was connected with the down-regulated gene EIF3E and NONHSAG009271 was linked to MYL12A (down-regulated). Moreover, NONHSAG034203 (up-regulated) was co-expressed with ADM5 (up-regulated) in low-grade NMI cancer, while the down-regulated NONHSAG045391 was connected with the down-regulated DEGs DAD1 and STUB1 in high-grade NMI cancer and invasive bladder cancer. Our study indicates that NONHSAG013805 and NONHSAG009271 may play key roles in bladder cancer via co-expressing with EIF3E and MYL12A, respectively. Moreover, NONHSAG034203 may be involved in low-grade NMI bladder cancer via targeting ADM5, while NONHSAG045391 may contribute to high-grade NMI and invasive bladder cancer via targeting DAD1 and STUB1.