The aim of the study was to define specific genetic profile in Ta and T1 urinary bladder carcinoma patients with and without recurrence by gene expression microarrays. Eleven patients with the time to recurrence shorter than one year (patients with recurrence) and 11 patients with time to recurrence longer than 4 years (patients without recurrence) were enrolled.Data from microarrays were subjected to a panel of statistical analyses to identify bladder cancer recurrence-associated gene signatures. Initial screening using the GeneSpring and Bioconductor software tools revealed a putative set 47 genes differing in gene expression in both groups. After the validation, 33 genes manifested significant differences between both groups. The significant expression was observed in the group of patients without recurrence by 30 genes of which the highest differences were detected by ANXA1, ARHGEF4, FLJ32252, GNE, NINJ1, PRICKLE1, PSAT1, RNASE1, SPTAN1, SYNGR1, TNFSF15, TSPAN1, and WDR34. These genes code for signal transduction, vascular remodeling and vascular endothelial growth inhibition mainly. In the group with recurrence, 3 genes had significant differences, the highest differences were identified by two genes (PLOD2 and WDR72).Loci of genes with significant changes of gene expression were located on characteristic chromosomes for bladder cancer: 7 loci on chromosome 9, 8 loci on chromosomes 1, 2, 3, 12, 14, 15, 16, and 22. We have selected and validated 15 genes that are differentially expressed in superficial bladder cancer. We hope that this cohort of genes will serve as a promising pool of candidate biomarkers for early stage bladder cancer. Our results indicate that it may be possible to identify patients with a low and high risk of disease recurrence at an early stage using a molecular profile.
Key words: bladder cancer, non-muscle invasive urothelial tumors, gene expression microarraysBladder cancer (BC) is the sixth most frequent solid tumor in men and thirteenth in women in Czech Republic with 1827 and 650 new cases in 2005, respectively [1] and 375.000 new cases and 145.000 deaths worldwide annually [2]. Urothelial carcinoma (UC) is a heterogenous neoplasm manifesting either non-muscle invasive bladder cancer (NMIBC) -Ta, T1 and Tis by approximatelly 75 % newly diagnosed cases or muscle invasive (T2-T4) and metastatic tumor (25 %) [3,4]. After initial treatment of NMIBC by transurethral resection (TURB) up to 80 % of patients develop recurrences. From 10 % to 15 % of them progress to muscle invasive cancer [5,6]. For treatment and follow up of patients it is crucial to predict the recurrence and progression potential of non-muscle invasive bladder cancer. Therefore new methods are engaged to identify new prognostic markers based on the molecular nature of the tumor development and recurrence [7,8].The objective of our study was to identify the genes differing in gene expression in tumors with and without recurrence. Among the genes it might be determined a gene or several genes serving as factors for furt...
