764 Int Urol Nephrol (2012) 44:761–767 Table 1 Number of positive qRT-PCR results for mRNAs selected from published reports (genes 1–10) or from analysis of microarray data (genes 11–14) in blood samples collected from two groups of controls: group A—healthy subjects Candidate markers No. Gene name Control subjects recruited from the laboratory staff; group B—healthy subjects with no illnesses or known history of malignancy selected among individuals who underwent a screening colonoscopy Literature-based Microarray-based 1 2 3 4 5 6 7 8 9 10 11 12 13 14 EGFR UPK2 CD47 IGFBP7 SNX16 TP53 KIT PDGFRA TERT VEGF COL1A1 COL3A1 KRT7 AGR2 Group A (n = 17) Group B (n = 15) 0 1 17 17 17 17 17 17 16 17 1 2 5 1 0 14 15 15 15 15 15 15 14 15 0 7 8 0 qRT-PCR primers sequences 50 C 30 (Sybr Green chemistry) or Taqman Gene Expression assay ID Hs01076092_m1 Hs00171854_m1 Hs00179953_m1 F:TGCGAGCAAGGTCCTTCCATA R:ATGAGGACAGGTGTCGGGATTC F:AGTCCTCTGCACTTGAGGTTGA R:CAGCATCATATGCCACTTCTGCT F:TTGCAATAGGTGTGCGTCAGA R:AGTGCAGGCCAACTTGTTCAG F:GGCGACGAGATTAGGCTGTT R:CATTCGTTTCATCCAGGATCTCA F:GGCATTCTTTGCAATACTGCTTAA R:CATCTGCCGATAGCACAGTGA Hs99999022_m1 F:AGGAGGAGGGCAGAATCATCA R:CTCGATTGGATGGCAGTAGCT Hs00164004_m1 Hs00943809_m1 Hs00559840_m1 Hs00180702_m1 Forward primer sequence; Reverse primer sequence clinical outcome [28]. However, we could not ﬁnd any correlation between the level of expression or the PCR-positive-signal frequency of any of the studied markers for CTCs with the grading of bladder tumor (not shown). Blood biomarkers levels after TURBT To detect whether TURBT may inﬂuence the level of the circulating urothelial cells, in the peripheral blood, expression of all studied marker genes was analyzed in blood samples collected before and 1, 3, 7 and 30 days after surgery. Four genes (Table 2) exhibited signif- icant differences in gene expression between controls and cancer patients found at least at one time point after TURBT. While TURBT did not signiﬁcantly increase the number of PCR-positive results of any transcripts, a positive EGFR expression was 123 signiﬁcantly less frequent (P = 0.0021) at 30th day compared to results obtained on day 0. Discussion The detection of CTCs has been demonstrated in the blood of patients with colon, breast, prostate and other cancers [4–8]. Some of these markers may speciﬁcally detect circulating urothelial cells. Most reported studies employed RT-PCR-based analyses, and while they generally exhibited well-documented sensitivity, their speciﬁcity might be questionable. Analysis of epithelial-speciﬁc mRNAs by a qRT- PCR is a sensitive technique that allows CTCs identi- ﬁcation in the peripheral circulation. However, because of the limited speciﬁcity of these assays, leading to both false-positive and false-negative results, proper