Demetrios Delakas

Transcriptional activation of H-ras, K-ras and N-ras proto-oncogenes in human bladder tumors

In this study we demonstrate the involvement of ras oncogenes in bladder cancer at the level of RNA overexpression. We examined 26 bladder specimens, consisting of paired tumor and adjacent normal tissue and found that H-ras transcripts were overexpressed in 39% of the specimens while K-ras and N-ras in 58% of total specimens. Each tumor specimen had a unique pattern of overexpression for the three ras genes. A competitive-RT-PCR was employed for H-ras and a beta-actin control gene was co-amplified with K-ras or N-ras genes. These results indicate that the involvement of ras oncogenes in bladder cancer could be relative to overexpression of these genes.

Expression Profile of CYP1A1 and CYP1B1 Enzymes in Colon and Bladder Tumors

Background The cytochrome P450 CYP1A1 and CYP1B1 enzymes are involved in carcinogenesis via activation of pro-carcinogenic compounds to carcinogenic metabolites. CYP1A1 and CYP1B1 have shown elevated levels in human tumors as determined by qRT-PCR and immunohistochemical studies. However studies that have examined CYP1 expression by enzyme activity assays are limited. Results In the current study the expression of CYP1A1 and CYP1B1 was investigated in a panel of human tumors of bladder and colorectal origin by qRT-PCR and enzyme activity assays. The results demonstrated that 35% (7/20) of bladder tumors and 35% (7/20) of colon tumors overexpressed active CYP1 enzymes. CYP1B1 mRNA was overexpressed in 65% and 60% of bladder and colon tumors respectively, whereas CYP1A1 was overexpressed in 65% and 80% of bladder and colon tumors. Mean mRNA levels of CYP1B1 and CYP1A1 along with mean CYP1 activity were higher in bladder and colon tumors compared to normal tissues (p<0.05). Statistical analysis revealed CYP1 expression levels to be independent of TNM status. Moreover, incubation of tumor microsomal protein in 4 bladder and 3 colon samples with a CYP1B1 specific antibody revealed a large reduction (72.5 ± 5.5 % for bladder and 71.8 ± 7.2% for colon) in catalytic activity, indicating that the activity was mainly attributed to CYP1B1 expression. Conclusions The study reveals active CYP1 overexpression in human tumors and uncovers the potential use of CYP1 enzymes and mainly CYP1B1 as targets for cancer therapy.

Genetic detection of bladder cancer by microsatellite analysis of p16, RB1 and p53 tumor suppressor genes.

PURPOSE We investigated the incidence of genetic alterations in urine specimens from patients with bladder cancer. MATERIALS AND METHODS A total of 28 cytological urine specimens were assessed for microsatellite alternations, and 15 microsatellite markers were located on p53, RB1 and p16 regions. In 15 patients DNA from tumor specimens was also available. RESULTS Loss of heterozygosity was detected in 26 of 28 patients (93%) in at least 1 microsatellite marker. Allelic losses were found in 18 patients (64%) for the p16 locus, in 8 (29%) for the RB1 locus and in 17 (61%) for the p53 region. In contrast, no microsatellite alterations were found in the normal group without evidence of bladder cancer. In 11 cases genetic alterations in the cytological urine specimens were not detectable in the corresponding tumor specimen, suggesting heterogeneity of bladder cancer. CONCLUSIONS The detection of loss of heterozygosity in cytological urine specimens may be a prognostic indicator of early detection of bladder cancer. Our results suggest that microsatellite analysis of urine specimens represents a novel, potentially useful, noninvasive clinical tool to detect bladder cancer.

Safety of ultrasound-guided transrectal extended prostate biopsy in patients receiving low-dose aspirin.

PURPOSE To determine whether the peri-procedural administration of low-dose aspirin increases the risk of bleeding complications for patients undergoing extended prostate biopsies. MATERIALS AND METHODS From February 2007 to September 2008, 530 men undergoing extended needle biopsies were divided in two groups; those receiving aspirin and those not receiving aspirin. The morbidity of the procedure, with emphasis on hemorrhagic complications, was assessed prospectively using two standardized questionnaires. RESULTS There were no significant differences between the two groups regarding the mean number of biopsy cores (12.9 +/- 1.6 vs. 13.1 +/- 1.2 cores, p = 0.09). No major biopsy-related complications were noted. Statistical analysis did not demonstrate significant differences in the rate of hematuria (64.5% vs. 60.6%, p = 0.46), rectal bleeding (33.6% vs. 25.9%, p = 0.09) or hemospermia (90.1% vs. 86.9%, p = 0.45). The mean duration of hematuria and rectal bleeding was significantly greater in the aspirin group compared to the control group (4.45 +/- 2.7 vs. 2.4 +/- 2.6, p = < 0.001 and 3.3 +/- 1.3 vs. 1.9 +/- 0.7, p < 0.001). Multivariate logistic regression analysis revealed that only younger patients (mean age 60.1 +/- 5.8 years) with a lower body mass index (< 25 kg/m2) receiving aspirin were at a higher risk (odds ratio = 3.46, p = 0.047) for developing hematuria and rectal bleeding after the procedure. CONCLUSIONS The continuing use of low-dose aspirin in patients undergoing extended prostatic biopsy is a relatively safe option since it does not increase the morbidity of the procedure.

Mutational analysis of the BRAF gene in transitional cell carcinoma of the bladder.

PURPOSE Mutational activation of the MAP kinase pathway is frequently found in many types of cancer. Recently, activating mutations in the BRAF gene, an important activator of this pathway, have been described in several tumor types including melanoma, colorectal and papillary thyroid cancer. The most frequent mutation in exon 15 (V600E) as well as several other mutations within exons 11 and 15 result in constitutive activation of the oncoprotein. MATERIALS AND METHODS Our study aimed to investigate BRAF mutations in 30 human bladder tumors and their adjacent normal tissues. The V600E mutation was screened by PCR/RFLP and exons 11, 14 and 15 of BRAF including intron-exon boundaries were sequenced. RESULTS We detected two tumor specimens bearing two different mutations, both of which were found in exon 15. One sample showed the T1799A (V600E) and the other the G1798T (V600L) mutation. The first specimen was stage pT1a and grade II, whereas the second was stage pT2b and grade III. No mutations within the coding region of exons 11, 14, 15 and the intron-exon junctions for the remaining samples were found. CONCLUSIONS Our results suggest that involvement of BRAF mutations in the development of transitional cell carcinoma of the bladder is infrequent.

Prospective comparative study of endoscopic management of bladder lithiasis: is prostate surgery a necessary adjunct?

OBJECTIVES To present the results of a prospective study comparing transurethral cystolithotripsy and simultaneous transurethral resection of the prostate (TURP), with transurethral cystolithotripsy and medical treatment of benign prostatic hyperplasia. The traditional dogma that bladder lithiasis constitutes an absolute indication for prostatic surgery has recently been questioned. METHODS A total of 64 patients with bladder calculi were included in the present study. In all patients, stone clearance was achieved transurethrally. The patients in group 1 (n=32) underwent TURP during the same session, and the patients in group 2 (n=32) underwent medical therapy for benign prostatic hyperplasia (tamsulosin plus finasteride). RESULTS The mean follow-up was 28.23±8.84 months. No statistically significant differences were found between the 2 groups regarding the preoperative parameters (age, International Prostate Symptom Score, prostatic volume, peak urinary flow rate, postvoid residual urine volume, prostate-specific antigen level, and bladder stone characteristics). Both groups experienced statistically significant postoperative improvements in the International Prostate Symptom Score, peak urinary flow rate, and postvoid residual urine volume. However, patients in group 1 experienced a more pronounced improvement in the International Prostate Symptom Score (P=.02) and peak urinary flow rate (P=.001). In total, 11 patients in group 2 underwent TURP during follow-up, with medical management considered to have failed. Multivariate logistic regression analysis revealed the postvoid residual urine volume as an independent risk factor that predicted the need for TURP in group 2 patients (odds ratio 1.033, 95% CI for odds ratio 1.007-1.060, P=.014). CONCLUSIONS The findings of the present study have provided useful information on the natural history of bladder lithiasis, particularly in the context of improved patient consultation.

Expression of p53 family genes in urinary bladder cancer: correlation with disease aggressiveness and recurrence

Abstractp53 is a tumour suppressor gene with an established role in the majority of human neoplasias. Its homologues—p63 and p73—cannot be classified as tumour suppressors, since they encode isoforms with oncogenic properties as well. p63 plays a crucial role in epithelial cell differentiation and p73 is essential for neuronal cell development. The p63 and p73 expressions have been investigated in a variety of human tumours including bladder carcinomas; yet, this is the first study to simultaneously analyse the transcriptional levels of all p53 family members in bladder cancer. Using quantitative real-time polymerase chain reaction, we measured the mRNA expression of p53, p63 and p73 in 30 bladder tumours, each paired with adjacent normal tissue. All three studied genes were up-regulated in malignant specimens, p53 by 1.9-fold, p63 by threefold and p73 by twofold, respectively. Further analysis suggested that p63 and p73 act independently of p53 in the malignant bladder epithelium. Statistical analysis revealed that p63 overexpression was more frequent in recurrent bladder tumours (p = 0.045) and in older patients (p = 0.022). Papillary tumours also exhibited abnormal p63 expression (p = 0.026). Finally, p73 was up-regulated in Grade III one-site tumours (p = 0.040). Our results indicate that all p53 family members are abnormally expressed in bladder cancer but do not act synergistically. High levels of p63 correlate with non-muscle invasive tumours with frequent relapses, whereas p73 overexpression is associated with a more aggressive tumour phenotype.

Plasmacytoid urothelial carcinoma of the bladder: a rare malignancy.

In 2004, the WHO recognized the plasmacytoid subtype as a distinct variant of vesical malignancy. We present a case of plasmacytoid urothelial carcinoma of the bladder treated with radical surgery and adjuvant chemotherapy, thus achieving long-term survival. A 70-year-old woman presented with persistent dysuria and underwent cystoscopy which revealed the presence of diffuse deformity, involving the right lateral vesical wall. Histology revealed the presence of muscle-invasive urothelial carcinoma of the plasmacytoid variant. The patient subsequently underwent radical cystectomy and orthotopic ileal neobladder substitution, as well as adjuvant chemotherapy. At 36 months of follow-up, the patient is free of local recurrence and metastases, while her voiding function is well preserved. Bladder plasmacytoid urothelial carcinoma is considered a rare tumor, with unique microscopic and immunohistochemical features. The ideal therapeutic approach is debatable, but the combination of radical surgery and chemotherapy should constitute the mainstay of management.