BCAN Think Tank session 1: Overview of risks for and causes of bladder cancer

A multidisciplinary approach in muscle-invasive disease: novel chemotherapy combinations and targets in chemoradiation

The basic management of bladder cancer has changed depressingly little in the last 20 years, with a largely unquestioning acceptance of the role of surgery as the standard of care despite a rising mean age at diagnosis, now well into the mid-70s, meaning many patients will be high risk for a major surgical procedure. Overall survival rates for those diagnosed with bladder cancer have not improved for many years. There is a growing body of studies demonstrating the safety and efficacy of bladder preservation with combined chemo-radiation with good long-term function after such treatment. Two recent studies from the United Kingdom compared radiation alone with sensitized radiotherapy using distinct strategies, one (BCON) focusing on trying to improve tumor oxygenation, one (BC2001) using the combination of 5FU and mitomycin C. Importantly, both studies collected data on late toxicity and showed both good function and low rates of serious side effects with no increase with radio-sensitization. Furthermore, there is good evidence that survival after salvage cystectomy is similar to that seen after primary surgery, suggesting a strategy of primary chemo-radiation with salvage surgery (as used, for example, in anal cancer) may be both rational and safe. This article reviews the evidence on outcomes with chemo-radiation and calls for a rethink in our approaches to this major cancer killer.

Polymorphic variants of H-RAS protooncogene and their possible role in bladder cancer etiology

Introduction

H-RAS gene is a protooncogene encoding p21ras, a small protein with GTPase activity. This protein is a component of many signaling cascades, while mutations in H-RAS gene are often found in urinary bladder cancer and leads to continuous transmission of signals stimulating cancer cell growth and proliferation. The T81C polymorphism of H-RAS gene is a SNP, which, although does not seem to impair p21ras protein structure and function, may contribute to the development of bladder cancer.

Objectives

The aim of our study was to characterize the prevalence and clinical significance of T81C polymorphism in patients with diagnosed bladder cancer.

Materials and methods

132 patients with diagnosed urinary bladder cancer were included in this study. The control group consisted of 106 healthy individuals. The experimental material was DNA, isolated from tumor tissue and peripheral blood lymphocytes. T81C polymorphism was detected using the MSSCP method and DNA sequencing.

Results

In the examined DNA samples, frequent polymorphic variations were found in codon 27 of H-RAS gene. In order to assess the clinical relevance of the polymorphism, the results were compared with those for the control group. The homozygous CC variant occurred more frequently in bladder cancer patients than in healthy individuals.

Conclusions

DNA polymorphisms start to play an important role in evaluation of disease risk and progression. The occurrence of multiple variants of the same gene may contribute to differences in reactions to specific medications and sensitivity to carcinogens or DNA repair capacity. Our study demonstrated T81C polymorphism of H-RAS gene to have seemingly been associated with an increased risk of bladder cancer development.

Detection of loss of heterozygosity in patients with urinary bladder carcinoma: neoplastic tissue vs. urine sediment cells

Introduction

Loss of heterozygosity (LOH) is frequently observed in urinary bladder neoplasms. In the reported study, an attempt was undertaken to determine the loss of heterozygosity of TP53(17p13), RB1(13q14), CDKN2A/ ARF(9p21) genes in DNA from neoplastic tissue, collected from patients with diagnosed urinary bladder carcinoma, and to compare the results with those of LOH evaluation in DNA isolated from urine sediment cells.

Material and methods

After isolation, DNA was amplified (PCR) by means of primers to five polymorphic microsatellite markers, the products being then separated on agarose gel. Following the method, a total of 125 DNA samples were obtained, isolated from neoplastic cells, together with 125 corresponding DNA samples, isolated from urine sediment cells.

Results

The loss of heterozygosity in at least one marker was identified in 39.2%. (49/125) of DNA from studied tumors and in 34.3% (43/125) of DNA samples, isolated from urine sediment cells. An analysis of LOH from the DNA, isolated from urine sediment cells, allowed for identification of 81.8% of neoplastic tumors with 99.7% specificity.

Conclusions

Our observations have demonstrated that LOH within 13q14, 17p13 and 9p21 loci is more often observed in clinically more advanced neoplasms. LOH in 17p13 locus is more frequently found in tumors at high histopathological stage, while in low-stage neoplasms, LOH is most often observed on chromosome 9. The high sensitivity (81.8%) and specificity (99.7%) of LOH studies in DNA, isolated from urine sediment cells, make this technique an advantageous, non-invasive method for detection and screening of bladder cancer.