Gene expression test for the non-invasive diagnosis of bladder cancer: A prospective, blinded, international and multicenter validation study.

OBJECTIVE: This study aimed to validate, in a prospective, blinded, international and multicenter cohort, our previously reported four non-invasive tests for bladder cancer (BC) diagnosis based on the gene expression patterns of urine. METHODS: Consecutive voided urine samples from BC patients and controls were prospectively collected in five European centres (n=789). Finally, 525 samples were successfully analysed. Gene expression values were quantified using TaqMan Arrays and previously reported diagnostic algorithms were applied to gene expression data. Results from the most accurate gene signature for BC diagnosis were associated with clinical parameters using analysis of variance test. RESULTS: High diagnostic accuracy for the four gene signatures was found in the independent validation set (area under curve [AUC]=0.903-0.918), with the signature composed of two genes (GS_D2) having the best performance (sensitivity: 81.48%; specificity: 91.26%; AUC: 0.918). The diagnostic accuracy of GS_D2 was not affected by the number of tumours (p=0.58) but was statistically associated with tumour size (p=0.008). Also, GS_D2 diagnostic accuracy increases with increasing BC tumour risk. We found no differences in the performance of the GS_D2 test among the populations and centres in detecting tumours (p=0.7) and controls (p=0.2). CONCLUSIONS: Our GS_D2 test is non-invasive, non-observer dependent and non-labour-intensive, and has demonstrated diagnostic accuracy in an independent, international and multicenter study, equal or superior to the current gold standard (cystoscopy combined with cytology). Additionally, it has higher sensitivity than cytology while maintaining its specificity. Consequently, it meets the requirements for consideration as a molecular test applicable to clinical practice in the management of BC.

Downregulation of protein tyrosine phosphatase PTPL1 alters cell cycle and upregulates invasion-related genes in prostate cancer cells.

PTPL1, a non-receptor type protein tyrosine phosphatase, has been involved in the regulation of apoptosis and invasiveness of various tumour cell types, but its role in prostate cancer remained to be investigated. We report here that downregulation of PTPL1 by small interfering RNA in PC3 cells decreases cell proliferation and concomitantly reduces the expression of cell cycle-related proteins such as cyclins E and B1, PCNA, PTTG1 and phospho-histone H3. PTPL1 downregulation also increases the invasion ability of PC3 cells through Matrigel coated membranes. cDNA array of PTPL1-silenced PC3 cells versus control cells showed an upregulation of invasion-related genes such as uPA, uPAR, tPA, PAI-1, integrin α6 and osteopontin. This increased expression was also confirmed in PTPL1-silenced DU145 prostate cancer cells by quantitative real time PCR and western blot. These findings suggest that PTPL1 is an important mediator of central cellular processes such as proliferation and invasion.

Immunohistochemical expression of Hsp60 correlates with tumor progression and hormone resistance in prostate cancer.

OBJECTIVES: To investigate the expression of Hsp60 protein in prostate cancer biopsy samples, and its association with prognostic clinical parameters and hormone resistance and survival. Molecular chaperones are involved in protein folding, protein degradation, and protein trafficking among subcellular compartments. METHODS: We selected 107 patients with localized and locally advanced prostate cancer at our hospital from 1999 through 2004. We performed an analysis by western blot and immunohistochemistry on paraffin-embedded tissue sections. Clinical data were used to determine associations between immunohistochemical expression of Hsp60 and tumor behavior. RESULTS: The expression level of Hsp60 was significantly increased in tumors with high Gleason score (P < .001). Hsp60 expression was also significantly associated with initial serum PSA levels (P < .01) and with the presence of lymph node metastasis (P < .003). In 50 locally advanced cancers treated by androgen ablation we found an association between high Hsp60-expressing tumors and an early onset of hormone refractory disease (P < .02) and reduced cancer-specific survival (P < .05). CONCLUSIONS: Hsp60 protein is overexpressed in poorly differentiated prostate cancers. Hsp60 expression is strongly associated with prognostic clinical parameters, such as Gleason score, initial serum PSA levels, and lymph node metastasis and with the onset of hormone-refractory disease and reduced cancer-specific survival. Identification of such markers could be of relevance in the clinical management of prostate cancer.