Genetic aberrations of NAT2 and chromosome 8: their association with progression in transitional cell carcinoma of the urinary bladder

Prognostic Value of c-Myc Immunohistochemical Expression in Muscle Invasive Urothelial Carcinoma of the Urinary Bladder: A Retrospective Study

Objective:

This study aimed to investigate the immunohistochemical expression of c-Myc in muscle invasive urothelial carcinoma (MIUC) of the urinary bladder and to evaluate the correlation of c-Myc expression with different clinicopathological parameters and outcome, including a relatively new histopathological tumor characteristic that is the growth pattern of tumor invasion.

Methods:

A total of 66 formalin-fixed and paraffin-embedded sections of MIUC obtained from radical cystectomy specimens were enrolled. The sections were stained with c-Myc antibody using immunohistochemistry technique.

Results:

Tumor cells showed variability in nuclear c-Myc expression according to the growth pattern of invasion. The median H-score of nuclear expression of infiltrative pattern was significantly higher than that of non-infiltrative pattern (p<0.001). Nuclear expression of c-Myc in tumor tissue had a significant association with poor prognostic factors (sarcomatoid variant (p<0.001), perineural invasion (p=0.037), lymphovascular invasion (p<0.001), lymph node metastasis (p<0.001), distant metastasis (p=0.042) and advanced stage grouping (p=0.001). Kaplan Meier survival analysis demonstrated that c-Myc expression could not be significantly correlated with overall survival or disease free survival rates.

Conclusion:

Nuclear c-Myc seems to have a prominent role in epithelial to mesenchymal transition with consequential in tumor progression and metastasis, while it is not as much useful to predict the clinical behavior of patients with MIUC.

NAT2*5/*5 genotype (341T>C) is a potential risk factor for schistosomiasis-associated bladder cancer in Egyptians

Arylamine N-acetyl transferase (NAT2) displays extensive genetic polymorphisms that affect the rates of acetylation of drugs and genotoxic compounds such as amine carcinogens. To investigate whether the slow acetylator genotype is a risk factor for development of bladder cancer following schistosomal infection of the urinary tract, the authors determined the frequencies of 3 common polymorphisms in the NAT2 gene (341T>C, 590G>A, and 282C>T), which are associated with impaired acetylation activity, in control subjects (n=61; mean age 34.3+/-9.2 years) and in schistosomiasis-associated bladder cancer patients (n=55; 52+/-10.9 years) from the Egyptian population. Genotyping was carried out using rapid cycle PCR on the LightCycler, and subjects were assigned to a slow, intermediate, or rapid acetylator phenotype on the basis of the genotypes. The frequencies of the mutant alleles observed in the controls from the present study were similar to those reported previously for both the Egyptian population and other Arab populations. Patients showed a higher prevalence (78.2%) of slow acetylator phenotype than controls (67.2%), but this did not reach statistical significance (P=0.19). However, there were significantly more individuals who were carriers of 2 mutant 341T>C alleles (NAT2*5/*5 genotype) in the patient group compared with controls (odds ratio 2.6, CI 1.02-6.67, P=0.026). The alloenzyme encoded by this allele has been shown to display a large reduction in its catalytic activity. In conclusion, these data suggest that the NAT2*5/*5 genotype is a potential risk factor for development of urinary bladder cancer in patients with prior schistosomiasis infection.

Chromosomal High-Polysomies Predict Tumour Progression in T1 Transitional Cell Carcinoma of the Bladder

The main prognostic factor generally accepted for tumour progression in T1 transitional cell carcinoma (TCC) of the bladder is histological grade. Despite this fact it is considered inaccurate to make clinical decisions on individuals. It appears that progression from minimally invasive to deeply invasive cancer is concurrent with the acquisition of genomic alterations that increase the malignant potential of cancer cells. The aim of this study is to determine if changes in chromosomes 7, 8, 9 and 17 copy number can be used to predict recurrence and progression in patients with T1 TCC of the urinary bladder.

METHODS

Thirty-one T1 TCC samples were analyzed for chromosomal alterations by fluorescence in situ hybridization using centromeric probes for chromosomes 7, 8, 9 and 17. Clinical data were collected from the patients' clinical records and correlated with chromosomal studies.

RESULTS

Histological grade was confirmed as a prognostic factor of tumour progression (p=0.01). None of the cytogenetic alterations demonstrated in the studied group could be related to tumour recurrence. The high-polysomies (five or more copies) of chromosomes 8, 9 and 17 showed predictive value (p=0.05, 0.05, 0.03 respectively) for tumour progression since it was observed that patients with high-polysomy of these chromosomes showed more risk of tumour progression towards muscle-invasive disease than those without high-polysomy alteration.

CONCLUSION

Our findings suggest a possible prognostic significance of highly aneuploid cells (high-polysomies of chromosomes 8, 9 and 17) in tumour progression of T1 TCC bladder tumours. FISH analysis is a reproducible technique for evaluating cytogenetic alterations and could contribute to the assessment of the individual prognosis of T1 transitional cell carcinoma of the bladder.

Primary care update on kidney and bladder cancer: a urologic perspective

The past decade has witnessed many substantive changes in the approach to the diagnosis and treatment of both kidney and bladder cancer. In part, this is based on changes in the understanding of their carcinogenesis and pathogenesis, an appreciation of new concepts in their classification, and the incorporation of new technologies that have emerged. This article reviews advances and updates changes that have been made in the understanding of and approaches to these malignancies from the perspective of their urologic assessment and management while in the context of primary care issues.

Genetic aberrations of c-myc and CCND1 in the development of invasive bladder cancer

Detrusor muscle invasive transitional cell carcinoma is associated with poor prognosis and is responsible for the majority of bladder cancer related deaths. Amplifications of c-myc and CCND1 are associated with detrusor-muscle-invasive transitional cell carcinoma, however, their precise role in driving disease progression is unclear. Fluorescence in situ hybridisation on archival tissue from 16 patients with primary diagnosis of > or = pT2 transitional cell carcinoma and 15 cases with primary pTa/pT1 disease subsequently progressing to detrusor-muscle-invasion was performed, in the latter group both pre and post muscle invasive events were studied. No patients presenting with >/=pT2 had amplification of c-myc, two out of 16 (12.5%) had CCND1 amplification. Of patients who developed > or = pT2, two out of 15 (13.3%) had amplification of c-myc, both in > or = pT2, five out of 15 (33.3%) had CCND1 amplification, two in pTa/pT1 tumours, three in > or = pT2 transitional cell carcinomas. In total, two out of 31 (6.5%) of patients' > or = pT2 TCCs were amplified for c-myc and six out of 31 (19%) were amplified for CCND1. Eighty-seven per cent (40 out of 46) of tumours were polysomic for chromosome 8 and 80% (37 out of 46) were polysomic for chromosome 11 and this reflected the high copy numbers of c-myc and CCND1 observed. In almost all cases an increase in c-myc/CCND1 copy number occurred prior to invasion and persisted in advanced disease. Amplification of CCND1 or alterations in c-myc/CCND1 early in bladder cancer may have clinical relevance in promoting and predicting progression to detrusor-muscle-invasive transitional cell carcinoma.

A modified nick translation method used with FISH that produces reliable results with archival tissue sections

Nick translation is used to label DNA and RNA to produce probes for in situ hybridization and Northern and Southern blotting. Fluorescence in situ hybridization (FISH) is a widely applied technique used to determine chromosomal and genetic anomalies in many biological samples. Initially the technique was applied to metaphase preparations, but the usefulness of detecting genetic anomalies in solid tumors in situ has resulted in the development of modified protocols. Formalin fixed paraffin processed tissue sections present novel challenges when applying FISH; the probes must be small (between 200 and 600 base pairs) and pretreatment is necessary before the probes can be applied to tissue sections, to promote probe access to target DNA. Here we report on a modification of a nick translation method to produce a probe that can reliably be used with FISH in paraffin processed tissue sections.