Comparison of gene expression profiling of human non-muscle invasive bladder cancer and muscle invasive bladder cancer

The biological behaviors, clinical treatment, prognosis of nonmuscle-invasive bladder cancers (NMIBCs) and muscle-invasive bladder cancers (MIBCs) are distinct. Therefore, we performed high-through microarray screening of mRNA expression in 30 bladder tumors, to filter out some of the differential expression genes in NMIBCs and MIBCs.A total of 11 Genes in MIBCs versus in NMIBCs were considered differentially transcribed if they were transcribed ≤2.0 fold change and p<0.001 by unpaired T-test, including 9 up-regulated genes and 2 down-regulated genes in MIBCs (NR4A2, PLK3, CYR61, APOLD1, C13ORF33, LIG4, RBMS3, PCK2, AK098422, HSD17B3, RTN4). These candidate genes were validated in further and provide further insight into the discovery of new putative markers to identify MIBCs preoperatively. Newly diagnosed bladder cancer patients with the greatest tumor diameter >2.5 cm and without tumor peduncle preoperatively observed by cystoscopy were selected. All fresh frozen tissue including in this study were from bladder cancer patients underwent radical or partial cystectomy and were bladder urothelial carcinoma confirmed by pathologist. Cystectomy specimens from the maximal tumor were immediately reviewed by the pathologist, who visually selected the tumor zone to be immediately stored in RNA later (Ambion Austin, TX, USA) overnight and then stored at -80℃. Sixteen NMIBCs and fourteen MIBCs were examined with Agilent 4×44K Whole Human Genome Oligo Microarrays (G4112F) according to the manufacturer’s protocol.