Evaluation of overexpression of p53 tumor suppressor protein in superficial and invasive transitional cell bladder cancer: comparison with DNA ploidy

Altered p53/p16 expression is linked to urothelial carcinoma progression but largely unrelated to prognosis in muscle-invasive tumors

BACKGROUND

Most inactivating p53 mutations result in a nuclear p53 accumulation - detectable by immunohistochemistry (IHC). p53 alterations leading to a complete lack of p53 protein and absence of immunostaining do also occur - not easily detectable by IHC. p16 is upregulated in p53 inactivated cells. We hypothesized that a positive p16 IHC may help to distinguish p53 inactivation in IHC negative cases.

MATERIAL AND METHODS

We investigated p53 and p16 immunostaining on 2710 urothelial bladder carcinomas in a tissue microarray format to understand their impact in relation to clinicopathological parameters of disease progression and patient outcome.

RESULTS

p16 immunostaining was absent in normal urothelium but occurred in 63.5% (30.4% strong) of cancers. p16 strongly positive cases increased from pTaG2 low-grade (9.6%) to pTaG3 high-grade tumors (46.5%, p < .0001) but decreased from pTaG3 to pT4 (33.3%; p = .0030). Among pT2-4 carcinomas, p16 positivity was linked to high-grade (p = .0005) but unrelated to overall survival. p53 staining was negative in 8.4%, very weak in 15.4%, weak in 55.3%, strong in 4.7%, and very strong in 16.2% cancers. p53 negative (potentially p53 null phenotype), strong, and very strong p53 positivity increased from pTaG2 low-grade to pTaG3 high-grade tumors (p < .0001) and from pTaG3 to pT2-4 cancers (p = .0007). p53 staining was largely unrelated to histopathological parameters or patient prognosis among pT2-4 carcinomas, except of p53 strong/very strong immunostaining. p16 expression predominated in tumors with very strong, strong, and negative p53 staining and the combination of p53 negative/p16 strongly positive cancers was linked to features of tumor aggressiveness.

CONCLUSION

Aberrant p53 and p16 immunostaining increases during grade and stage progression although p53 negative and p16 positive immunostaining lack prognostic significance in pT2-4 carcinomas. Potential diagnostic features are that high level p16 expression is limited to neoplastic urothelium and p53 null phenotype to aggressive cancers (grade 3 and invasive).

Flow Cytometric and Immunohistochemical Correlations in High Incidence Human Solid Tumors

475 patients with carcinoma at different sites (141 colon-rectum; 102 breast; 50 stomach; 48 kidney; 46 head and neck; 41 bladder; 47 other sites) submitted to surgery have been analyzed after histopathological staging and grading, by flow cytometry (monoparametric DNA content analysis) and immunohistochemistry (p53, c-erbB-2, and PCNA expression). In breast cancer patients the presence of receptors for estrogen (ER) and progesterone (PGR) has also been determined. Flow cytometry-derived parameters were DNA ploidy, fraction of cells in S-phase (SPF), and DNA content heterogeneity (multiclonal stem cell lines with different DNA index and/or more than one subpopulations with different ploidy levels in different samples from the same tumor). Correlations of the results obtained by the different techniques have been attempted by the non-parametric Spearman's rank correlation approach. Significant associations (P «0.05) were found between the histopathological, immunohistochemical and flow cytometric parameters considered in some anatomical regions, such as stomach (p53 vs DNA content aneuploidy and vs heterogeneity), colon-rectum (TNM vs p53 and vs heterogeneity), bladder (grading vs DNA content aneuploidy and vs heterogeneity). Tumor heterogeneity proved to be dependent on the number of tumor samples taken. The results of this preliminary assessment will subsequently be compared with the data obtained from a currently ongoing follow-up survey.

Biomarkers in bladder cancer: translational and clinical implications

Bladder cancer is associated with high recurrence and mortality rates. These tumors show vast heterogeneity reflected by diverse morphologic manifestations and various molecular alterations associated with these disease phenotypes. Biomarkers that prospectively evaluate disease aggressiveness, progression risk, probability of recurrence and overall prognosis would improve patient care. Integration of molecular markers with conventional pathologic staging of bladder cancers may refine clinical decision making for the selection of adjuvant and salvage therapy. In the past decade, numerous bladder cancer biomarkers have been identified, including various tumor suppressor genes, oncogenes, growth factors, growth factor receptors, hormone receptors, proliferation and apoptosis markers, cell adhesion molecules, stromal factors, and oncoproteins. Recognition of two distinct pathways for urothelial carcinogenesis represents a major advance in the understanding and management of this disease. Nomograms for combining results from multiple biomarkers have been proposed to increase the accuracy of clinical predictions. The scope of this review is to summarize the major biomarker findings that may have translational and clinical implications.

Evaluation of p53 Nuclear Accumulation in Low- and High-Grade (WHO/ISUP Classification) Transitional Papillary Carcinomas of the Bladder for Tumor Recurrence and Progression

OBJECTIVES

To evaluate the association of p53 nuclear accumulation with recurrence and progression in transitional cell carcinomas of the bladder and to examine the distribution of p53 in low-grade and high-grade transitional cell carcinomas according to the World Health Organization/International Society of Urological Pathology classification.

PATIENTS AND METHODS

Nuclear accumulations of p53 were examined in a total of 99 patients with transitional cell carcinoma between May 1995 and October 1999. The mean age was 64 years. There were 94 (95%) men and 5 (5%) women. Following resection, surgical specimens were examined, and p53 accumulation with a 20% cutoff value was accepted as positive staining. Of the 99 patients, 52 (53%) had histologically superficial bladder tumors, and 47 (47%) had invasive tumors. Data concerning grade, stage, number of recurrences, and disease progression were available for each patient.

RESULTS

The median follow-up period was 55 months. 60 of the 99 patients (61%) had p53 overexpression. The difference for p53 overexpression between low-grade and high-grade tumors was significant (p < 0.05). In low- and high-grade tumors, there was no significant relationship for recurrence between p53-positive and p53-negative groups. But there was a statistically significant relationship between progression and histological grade of the tumors. p53 had no significant relationship with tumor recurrences (p > 0.05), but its relationship with progression was statistically significant (p < 0.05).

CONCLUSIONS

We did not find a correlation between tumor recurrence and p53 overexpression, but p53 overexpression has a predictive value in determining tumor progression. High-grade tumors had higher p53-positive values than low-grade tumors. This group of patients should be considered for radical therapies on the basis of other prognostic parameters.

Non-endothelial KDR/flk-1 expression is associated with increased survival of patients with urothelial bladder carcinomas

AIMS

To investigate the immunohistochemical expression of KDR/flk-1 in a series of 114 urothelial bladder carcinomas in relation to clinicopathological parameters, Ki67, p53 and Bcl-2 protein expression and patient survival. KDR/flk-1 is a high-affinity tyrosine kinase receptor for vascular endothelial growth factor (VEGF), on vascular endothelium. However, there is increasing evidence that KDR/flk-1 is also expressed by normal non-endothelial and tumour cells.

METHODS AND RESULTS

Immunohistochemistry was performed on paraffin sections using monoclonal and polyclonal antibodies. Statistical analysis was univariate (chi2 log rank test) and multivariate (Cox's model). KDR/flk-1 expression was observed in the cytoplasm of cancerous cells in 68.4% of cases. No statistically significant associations were observed between KDR/flk-1 expression and grade or stage of urothelial carcinomas, Ki67, p53 or Bcl-2 expression. In contrast, widespread KDR/flk-1 expression in more than 50% of cancerous cells was associated with increased survival, on univariate and multivariate analysis (P = 0.0119 and P = 0.042, respectively).

CONCLUSIONS

Although the biological significance of non-endothelial KDR/flk-1 expression has not yet been elucidated, its association with better patient survival may be related to the failure of non-endothelial KDR/flk-1 to mediate angiogenic and mitogenic effects.

P53 protein expression in transitional cell carcinoma of the bladder - experience of the University of Malaya Medical Centre

OBJECTIVES

To study the incidence of p53 oncoprotein overexpression and its relationship to tumour grade, stage and clinical prognosis in a cohort of local Malaysian patients.

METHODS

All cases of transitional cell carcinoma (TCC) of the bladder diagnosed and treated at the University of Malaya Medical Centre from January 1995 to December 2000 were retrieved from the hospital records. Sections from paraffin-embedded tissues were retrieved and stained for p53 oncoprotein using immunohistochemistry techniques. P53 oncoprotein results were analyzed in relation to tumour grade, stage and clinical prognosis. Fisher's exact test was used to evaluate the relationship between categorical variables and the Kaplan-Meier procedure was used to assess survival outcomes. The Cox regression model was used for multivariate analysis.

RESULTS

A total of 64 cases were studied. The mean follow-up period was 23.7 months. The number of p53 positive cases was significantly higher in high-grade (G3) (p = 0.006) and muscle-invasive tumours ( summation operator T2, p = 0.035). The status of p53 expression had no significant association with recurrence-free (p = 0.594) or overall survival (p = 0.955). In multivariate analysis, a multiplicity of tumours at presentation (p = 0.004) and a history of cigarette smoking (p = 0.016) were independent predictors of recurrence. Tumour stage (p = 0.024) was the single independent predictor for poor overall survival.

CONCLUSIONS

Overexpression of p53 is associated with TCC of higher grade and tumour stage. It had no significant impact on prognosis in this cohort of TCC cases.

Cyclin D1 expression in papillary superficial bladder cancer: its association with other cell cycle-associated proteins, cell proliferation and clinical outcome

Cyclin D1 contributes to regulate G1 progression by forming a complex with different cyclin-dependent kinases. It has oncogenic properties and is frequently overexpressed in several human tumor types. In our study, expression of cyclin D1 and Ki67, a proliferation marker, was evaluated by immunohistochemistry in human papillary superficial (pTa-pT1) bladder cancers and was correlated with p27(Kip1), p21(Waf1) and c-erbB-2 expression, with p53 gene status and protein expression, ploidy and cancer progression. Cyclin D1 expression was neither associated with tumor stage nor with tumor grade but high cyclin D1 expression (> or =25% positive nuclei) was significantly associated with p53 gene mutation (p = 0.012), low p21(Waf1) (p = 0.015) and high p27(Kip1) (p = 0.016) protein expression. Ki67 expression was not associated with tumor stage but a high proliferation index (> or =10% positive nuclei) was significantly associated with high tumor grade (p = 0.001) and with DNA aneuploidy (p = 0.005). There was no significant difference in proliferative activity between high and low cyclin D1 expressor tumors. Patients whose tumors showed high expression of cyclin D1 displayed a significantly longer disease-free survival (p < 0.001 by log-rank test). Increased Ki67 expression was significantly associated with shorter disease-free survival (p = 0.003). Both cyclin D1 (p = 0.027; RR = 1.898) and Ki67 (p = 0.047; RR = 1.932) protein expressions were independent predictors of reduced disease-free survival on a multivariate analysis that also included p27(Kip1) expression and tumor stage. The simultaneous presence of low cyclin D1, low p27(Kip1) and high Ki67 expression defined a "high-risk" group of patients who displayed a significantly increased risk of recurrence (p < 0.0001). These results suggest that evaluation of cell cycle-associated markers can help to identify high-risk patients and may affect the management of patients with papillary superficial bladder cancer.

p53 and ki67 expression as prognostic factors for cancer-related survival in stage T1 transitional cell bladder carcinoma

OBJECTIVE

To determine prognostic factors for survival in bladder transitional cell carcinoma (TCC), and the prognostic value of p53 and ki67.

MATERIAL AND METHODS

A study was made of patients with stage T1 primary bladder TCC (n = 175). The immunohistochemical study was carried out using DO7 and MIB-1 monoclonal antibodies, for p53 and ki67, respectively. Kaplan-Meier methodology was used for the survival analysis, and the log-rank test was applied in order to determine accumulated probability rates of survival. Moreover, Cox's multivariate regression analysis was also used to establish the variables associated with survival. Receiver operating characteristic (ROC) curves were also drawn, with the aim of determining the prognostic capacity of p53 and ki67.

RESULTS

The average follow-up period was 7.3 years. Cancer-related survival rates at 5 and 10 years were 89.51 and 80.68%, respectively. The increase in p53 and ki67 expressions paralleled the histological grade, both markers showing significant inter-group differences (P = 0.0000). The variables which modified cancer-related survival significantly in the univariate analysis were the following: tumour multifocality, solid microscopic morphology, large cell nucleus and a high expression of p53 and ki67. Independent cancer-related survival variables were: age, tumour size of >3 cm, a solid microscopic growth pattern and expression of p53.

CONCLUSIONS

The expression of p53, increase in age, tumour size of >3 cm and microscopic growth pattern are independent predictors for cancer-related survival. A positive correlation was observed, indicating that, the higher the expression of p53, the greater the probability of death.

Predictive value of topoisomerase II alpha immunostaining in urothelial bladder carcinoma

AIMS

The nuclear enzyme DNA topoisomerase II has been shown to be required for chromatin condensation and chromosomal segregation during mitosis; its isoform topo II alpha is linked with active cell proliferation in mammalian cells. The aim of this study was to examine the relation of the expression of topo II alpha to the biological behaviour of conventional urinary bladder cancer.

METHODS

Formalin fixed, paraffin wax embedded tissue from 94 specimens of bladder urothelial cancer were immuno-histochemically stained for topo II alpha. For each case, a topo II alpha index was determined. A similar index had been determined for Ki-67, a known cell proliferation marker. Each case had also been graded, staged, and evaluated for DNA ploidy as well as for p53 and bcl-2 immunoreactivity.

RESULTS

Raised topo II alpha expression (in > or = 10% of malignant nuclei) correlated with two adverse prognosticators--high grade (p = 0.027) and invasion of the muscularis propria (p = 0.013), but with no other evaluated parameter. By multivariate survival analysis using Cox's proportional hazard model, high expression of topo II alpha was found to be predictive for worse survival (p = 0.0047). Patients' age, tumour stage, and grade were also retained as independent prognostic factors (p = 0.0349, p = 0.00005, and p = 0.0130, respectively). The negative influence of increased topo II alpha immunopositivity on patients' survival was also seen in the subgroup of patients with non-muscle invasive carcinomas (p = 0.0004), in patients with a bcl-2 negative phenotype (p = 0.0330), and in those with low Ki-67 indices (p = 0.0341).

CONCLUSIONS

Because topo II alpha and Ki-67 failed to demonstrate a significant interrelation, they appear to be different molecules that both function at separate phases in the complex process of cellular proliferation. The assessment of increased topo II alpha immunoreactivity in specimens from urothelial carcinomas might help to select patients (particularly among those with superficial tumours) in the worse prognostic categories for new therapeutic strategies.

[DNA ploidy determination with flow cytometry, Ki-67 index and overexpression of p53 protein in 121 T1 superficial bladder carcinomas. Retrospective studies. Part II: Prognostic value and usefulness in the indication for prophylactic treatment with BCG]

OBJECTIVE

Evaluate the utility of Ki-67 label index, p53 expression and flow cytometry-DNA ploidy in the selection of groups to be treated with prophylactic BCG and the prognostic value compared with the classic variables (grade, lymphatic permeation, multiplicity, volume, primary).

MATERIAL & METHOD

121 superficial bladder tumors T1. 10% Cut-off level for Ki-67 and p53. Aneuplody is defined as a tumor with DNA index different of 1 or more than 20% in G2-M phase. 71 (58.7%) received BCG.

RESULTS

In uni and multivariate analysis positivity to Ki-67 is correlated with recurrence. Progression is correlated with lymphatic permeation (p .0003), volume (p .016), ploidy (p .022) and positivity to p53 (p .007). In multivariate analysis, volume and positivity to p53 are independent variables. None were of utility to prevent recurrence, but Ki-67 positive or aneuploid treated tumors had less progression (p .025 and p .009 respectively). The p53 negative treated tumors had less progression too.

CONCLUSIONS

Only Ki-67 is correlated with tumoral recurrence. P53 and tumor volume are correlated with stage progression. If the results are confirmed with bigger series, the Ki-67 positive and/or aneuploid tumors would obtain benefits of prophylactic treatment with BCG.

Genetic alterations and biological pathways in human bladder cancer pathogenesis

Human bladder cancers are heterogeneous. For example, at first presentation papillary transitional cell carcinomas (TCCs) are typically superficial and often multifocal. Papillary TCCs frequently recur, but most never progress to invasive TCC. In contrast, bladder carcinoma in situ (CIS) usually presents as a solitary flat lesion and, if left untreated, invariably progresses to invasive TCC. Some TCC are already invasive at the time of presentation. Squamous cell carcinoma (SCC) tends to present at a later stage than most TCCs and has a relatively aggressive clinical course. Multiple genetic alterations have been identified in invasive human bladder cancers and are present in different combinations and in different frequencies in the different manifestations of bladder cancer described above. A high percentage ( approximately 67%) of superficial papillary TCCs show early losses involving chromosome 9q, while very few show either a TP53 or a CDKN2/16 mutation. Thus, loss of 9q may be the earliest event in initiation of papillary TCC. In contrast, bladder CIS and SCC show relatively low percentages of 9q loss. However, approximately 65% of bladder CIS contain a TP53 alteration and approximately 67% of bladder SCC contain a CDKN2/p16 alteration. Mutations in these two tumor suppressor genes have powerful implications for loss of genome stability and cell growth regulation, respectively, consistent with the aggressive phenotypes of these cancers. Thus, these data suggest a model of bladder cancer pathogenesis in which the predominant genetic alteration may be the "initiating event" in cancer pathogenesis and may play a role in determining the biological potential of the tumor.

p53 immunohistochemistry in bladder cancer. Combined analysis: a way to go?

Seven years after the initial reports of the potential prognostic value of p53 immunohistochemistry in bladder cancer, key questions remain unanswered. This is mainly due to conflicting results obtained through multiple retrospective trials mostly performed with small numbers of poorly defined patients. The aim of this article was to investigate the feasibility of a combined analysis of previously published data. Based on a MEDLINE search in 1997, papers reporting on the prognostic role of p53 alterations were identified and the respective groups were invited to participate. Twenty-six of 38 study centers approached contributed patient data sets according to the protocol requirements. Acceptance of the initiative was similar in Europe, North America, and Australasia. A total of 3,421 patients with bladder cancer from 25 centers are included in the further analysis. With regard to gender, age distribution, and tumor stage the patients contributed are comparable with a normal bladder cancer population. Considering tumor grade, G2 tumors appear to be over- represented while the amount of G1 tumors is smaller than expected. The reason for this is probably related to the low rate of p53 accumulation in G1 tumors. No significant differences between those groups initially approached and those that finally cooperated were noted. Therefore, it is concluded that a combined study is feasible, and the patient data collected are representative for the population presented in the published literature. The final analysis of the data is the subject of current investigation.

[Molecular biology in bladder cancer]

Progress of molecular biology with regard to etiopathogeny of tumours in general, and cancer of the bladder in particular, is taking place at such a vertiginous pace that practising urologists find themselves overwhelmed in terms of their ability to learn and keep updated in so complex a subject. The understanding of certain molecular factors with critical influence on the formation, growth and progression of a tumour of the bladder, is forcing us to make unbiased assessments on the role they will play in the evolution and survival of this neoplasia. It is anticipate they will be much more reliable than traditionally established morphological factors such as grade and stage. We also include a literature review with an analysis and elucidation of the role played by oncogenes, tumor suppressor genes, vascular density markers, telomerase etc., in the formation and growth of cancer of the bladder and their likely relationships with already established clinico-pathological factors.

DNA ploidy and p53 protein expression in superficial transitional cell carcinoma of the bladder

Superficial transitional cell carcinoma of the bladder (STCCB) is a heterogeneous group of neoplasias with an unpredictable clinical course. In recent years many techniques have been used in order to predict the behaviour of these tumours at individual patient level. The aim of this study was to investigate in imprints from tumour biopsies the DNA ploidy and p53 protein expression in a group of 80 STCCB (pTa-pT1) patients in relation to histological grade and recurrence status. The DNA content was studied in Feulgen-stained imprints by the image analysis technique using a SAMBA 2005 analyser. In order to investigate p53 protein expression an avidin-extravidin immunocytochemical technique was used. According to our measurements a strong correlation was observed between recurrence status and DNA ploidy status (P < 0.001). No statistical difference was found in DNA ploidy status and grade of malignancy (P = 0.68). A statistically significant difference was found in p53 protein expression between recurrent and nonrecurrent tumours (P < 0.001). No statistically significant difference was found among tumours of grade I, grade II and grade III (P = 0.42). These results could provide useful information on the potential behaviour of STCCB.

Mutation of cell cycle regulators and their impact on superficial bladder cancer

Early cytogenetic studies in bladder cancer identify regions of chromosomal gain or loss that can be candidate loci for oncogenes and tumor suppressor genes. Oncogenes with potential prognostic significance identified in bladder cancer the RAS family, epidermal growth factor receptor, ERBB-2, MDM2, and cyclin D1. The TP53 gene has been the most thoroughly characterized tumor suppressor gene in bladder cancer, with correlation of TP53 alterations with type of carcinogenic exposure, tumor stage and grade, as well as prognosis. Studies evaluating alterations of the retinoblastoma pathway have identified the retinoblastoma gene, RB, p161NK4A/CDKN2, and E2F-1 as tumor suppressor genes with potential prognostic significance in patients with bladder cancer. Better understanding of the genetic mechanisms underlying bladder tumor development and progression will allow better prevention, diagnosis, and treatment strategies.

Biological markers in superficial bladder tumors and their prognostic significance

This article reviews the literature on some of the available biomarkers such as p53 and its down-stream effector p21 on superficial bladder tumor biology and their prognostic significance. The role of p53 tumor suppressor gene is controversial in superficial bladder cancer, possibly because analyzing one single effector of a pathway might hide the role of downstream effectors. The aggressiveness of this condition is related to proliferative activity as measured by Ki-67. Further studies are still necessary to draw definitive conclusions about the role of these different biological markers in superficial bladder cancer.

Bladder tumor markers: need, nature and application. 1. Nucleus-based markers

Urothelial tumors are common: their diagnosis and long-term management represent a large part of most urologists' workload. The majority of such tumors are 'superficial' and are mostly managed by repeated cystoscopic surveillance and treatment. A smaller but significant group of patients either start with, or subsequently progress to, more invasive disease, thus requiring an alternative and more invasive treatment. Maximizing the benefit/risk ratio of the diagnosis and the various treatment options of bladder tumors requires the availability of a reliable tumor marker. The concept of tumor markers encompasses the utilization of any detectable deviation from normality that is indicative of neoplasia. For bladder cancer, most of these markers are present in urine. In this part of the review we examine, from the clinician's point of view, the literature verdict on older techniques such as cytology and cytometry, as well as the current status of new nucleus-based tests such as P53, telomerase, NMP22 and Ki67.

The role of p53, MDM2 and c-erb B-2 oncoproteins, epidermal growth factor receptor and proliferation markers in the prognosis of urinary bladder cancer

The immunohistological expression of p53 and MDM2 oncoproteins was examined in paraffin embedded tissue from 106 patients with transitional cell carcinoma of the urinary bladder and was related to various clinicopathological features, the expression of proliferation associated markers (proliferating cell nuclear antigen - PCNA - and Ki-67), c-erb B-2 oncoprotein and epidermal growth factor receptor (EGFR), as well as to survival. MDM2 immunoreactivity was seen in 38% of our cases, and in 14% was accompanied by p53 positive immunohistochemistry. The rate of p53 positivity was associated with grade, stage and papillary status, whereas MDM2 immunopositivity increased with grade and stage (Ta VS T1), and MDM2 labeling index (LI) with stage. MDM2 expression was related to p53 expression and less strongly to proliferation rate (Ki-67 LI). The simultaneous p53 and MDM2 expression was more frequently observed in higher grade and stage tumours. C-erb B-2, EGFR and proliferation marker expression increased with grade, stage and non-papillary configuration. In univariate analysis high grade, solid growth pattern, advanced T-category, cystectomy, EGFR and Ki-67 expression were linked to shorter overall survival but only Ki-67 LI, along with T-category and type of therapy, had independent prognostic value. C-erb B-2 expression and stage were the two independent predictors of disease-free survival and Ki-67 LI and EGFR LI the independent predictors of post-relapse survival. For patients with superficial tumors PCNA LI emerged as the single independent determinator of survival. p53 and MDM2 expression did not appear to have any significant impact on survival, although the simultaneous expression of p53 and MDM2 turned out to be a highly significant parameter of shortened overall survival in univariate analysis.

Primary nonurachal adenocarcinoma in the bilharzial urinary bladder: deoxyribonucleic acid flow cytometric and morphologic characterization in 93 cases

OBJECTIVES

To characterize adenocarcinomas of the urinary bladder by their DNA profiles and their proliferative properties.

METHODS

Primary nonurachal adenocarcinomas, found in 93 patients with bilharzial bladder carcinomas, were studied using DNA flow cytometry. Tumor ploidy and S-phase fraction were related to tumor grade, stage, cell type, and lymph node status.

RESULTS

Aneuploidy with high S-phase fractions, found in 90% of the tumors, demonstrates the high malignancy potential of these tumors, the majority of which were found to be muscle-infiltrative. There were no relationships between ploidy or S-phase fraction and tumor grade and stage. Lymph node metastases, present in 24% of the 93 patients, were found exclusively in nontetraploid aneuploid tumors with high S-phase fractions exceeding 100%. Paraffin-embedded tissues compared with fresh material gave the same information on ploidy, whereas bladder washing did not provide adequate information.

CONCLUSIONS

The high aggressiveness of adenocarcinomas in the biharzial bladder is confirmed and can be explained by their proneness to develop gross chromosomal aberrations combined with high cell proliferation.

The prevalence of bcl-2, p53, and Ki-67 immunoreactivity in transitional cell bladder carcinomas and their clinicopathologic correlates

The aim of this study was to investigate the expression of bcl-2, p53 oncoproteins, and Ki-67 antigen in a series of transitional cell bladder carcinomas and its relation to the traditional prognostic indicators and patient's survival. One hundred six cases with transitional cell carcinoma (TCC) were examined for detection of bcl-2, p53 proteins, and Ki-67 antigen (MIB1 antibody). Bcl-2 immunohistochemical positivity was observed in 52% of TCCs and in 57% of low-grade and 44% of high-grade TCCs. Bcl-2 was also detected in normal urothelium and dysplastic lesions with basal cell expression, and negative staining was observed in carcinomas in situ. Tumor stage showed a significant inverse correlation with overall bcl-2 positivity. The loss of bcl-2 protein expression in higher-stage TCCs was statistically significant (Pt = .01). p53 protein was overexpressed in 50% of TCCs and more frequently in invasive and in carcinomas in situ than in superficial TCCs (Pt = .03). In contrast, detection of p53 was not observed in normal and dysplastic urothelium. p53 positivity was related to the degree of differentiation and to the stage of the disease (Pf = .01 and Pt = .03, respectively). Concerning Ki-67 antigen, its expression was found in 57.5% of TCCs. There was a strong overall correlation of Ki-67 with tumor stage (Pt = .002) and grade (Pf = .002). Univariate statistical analysis showed that the expression of p53 and Ki-67 was significantly correlated to poor prognosis (P = .02, P = .02, respectively). On multivariate analysis, none of these markers but only stage and grade were significantly correlated to prognosis (P = .02, P = .02, respectively). These findings suggest that overexpression of bcl-2 protein may be an early event in tumorigenesis. Tumors with loss of bcl-2 positivity and overexpression of p53 and Ki-67 had an unfavorable prognosis; however, in multivariate analysis, they had no independent prognostic value.

Bladder cancer: natural history, tumor markers, and early detection strategies

Transitional cell bladder carcinoma is characterized by a dichotomous, multichronotopic natural history. Low and moderate grade Ta lesions frequently recur, yet rarely invade, and carry an excellent prognosis with currently available treatments. High grade Ta lesions, tumors with lamina propria invasion (T1), and carcinoma in situ often progress to invasive disease, at which time overall prognosis is significantly decreased, despite various treatment alternatives. Although early detection of bladder tumors, prior to muscle invasion, should vastly improve our ability to save both bladders and lives, current methods of detection are neither sufficiently sensitive nor specific. Tumor marker analysis is an exciting new frontier in bladder cancer evaluation, and may have important applications to early detection strategies, in combination with simple hematuria testing and other selected noninvasive screening methods.

Correlation of allelic loss of the P53 gene and tumor grade, stage, and malignant progression in bladder cancer

BACKGROUND

We examined loss of heterozygosity (LOH) of the P53 gene in bladder cancer, and investigated the role of the P53 gene on malignant progression of papillary tumors. In addition, the clonality of recurrent bladder cancer was examined.

METHODS

LOH of the P53 gene was analyzed in 67 bladder cancers from 47 patients. DNA was extracted from formalin-fixed, paraffin-embedded tissues, amplified by the polymerase chain reaction (PCR) at 3 polymorphic loci in the P53 gene, and analyzed with nonradioisotopic single-strand conformation polymorphism (Non-RI SSCP) analysis.

RESULTS

Out of 40 informative samples, LOH was detected in 13 samples, containing 4 of 7 in grade 3 (57%), 9 of 23 in grade 2 (39%), and none of 10 in grade 1 (10%). Statistical significance was observed between the LOH in grades 1 and 2, and in grades 1 and 3. An analysis of 5 cases showing malignant progression revealed that 3 (60%) showed an LOH in the primary tumor, and 2 showed LOH in recurrent tumors, in contrast to LOH found in 3 cases of 19 (16%) not showing malignant progression. Four cases with metachronous recurrence exhibited LOH; 2 at recurrent tumors, 1 only at the initial tumor, and 1 at both tumors.

CONCLUSIONS

The alterations of the P53 gene were considered to correlate with tumor grade, and contribute to the malignant progression of bladder cancer. LOH in the P53 gene may serve as a clinical indicator for prognosis in superficial bladder cancer.

Immunohistochemical determination of p53 overexpression. An easy and readily available method to identify progression in superficial bladder cancer?

Overexpression of p53, as determined by immunohistochemical staining with the murine monoclonal antibody DO7, was determined in specimens of 46 primary superficial transitional cell bladder tumours (14 TaG2, 10 T1G2, 22 T1G3). A colon cancer specimen served as a positive control and normal mesenchymal cells in the specimens served as an internal negative control. An exceptionally high proportion 36/46 (78%) of the specimens were found to stain positively for p53 in over 20% of the cell nuclei. After a median follow-up of 7 years, ten patients developed progressive disease. Of these ten patients nine demonstrated p53 positivity, resulting in a sensitivity of 90%. However, 27 of the overall 36 patients (75%) with p53-positive tumours did not progress to a higher stage or metastatic disease. These findings suggest that p53 overexpression is not of predictive prognostic value in superficial transitional cell carcinoma. With 7 of 14 specimens (50%) of Ta tumours overexpressing p53, the results were suggestive of p53 mutation being an early event in carcinogenesis. When the threshold was set at 50% of the cell nuclei overexpressing p53, 16/46 (35%) classified as p53 positive. Of the 16 tumours staining positively for p53, 7 (46%) progressed and 9 (56%) did not. None of the Ta and 16 (50%) of the T1 tumours classified as positive. This more stringent definition of positivity still does not identify p53 positivity as a single prognostic factor. With 50% of T1 tumours classifying as positive, we still find that p53 mutation may be an early event in carcinogenesis of bladder cancer.

Prognostic value of p53 in muscle-invasive bladder cancer treated with preoperative radiotherapy

OBJECTIVES

The relationship of p53 mutations as analyzed immunohistochemically to radiation response and therapeutic outcome was examined in a cohort of 301 patients with muscle-invasive transitional cell carcinoma of the bladder treated relatively uniformly with preoperative radiotherapy (50 Gy in 25 fractions) 4 to 6 weeks prior to radical cystectomy.

METHODS

Adequate formalin-fixed paraffin-embedded archival tissue for the immunohistochemical staining of p53 using antibody DO1 was obtained in 109 patients. The median follow-up for those living was 91 months.

RESULTS

Overall, p53 staining was positive in 56% of the cases, with 60% positive in Stage T2 (n = 48), 42% in Stage T3a (n = 31), and 63% in Stage T3b (n = 30). Overexpression of p53 did not correlate with actuarial local control, distant metastasis freedom, disease freedom, or overall survival. However, significant associations were seen when these analyses were limited to patients with clinical Stage T3b disease. In this subgroup, the actuarial 5-year rates for patients with p53 positively and negatively stained tumors were 55% and 100%, respectively, for distant metastasis freedom (P = 0.01), 51% and 91% for disease freedom (P = 0.04), and 32% and 91% for overall survival (P = 0.006). Cox proportional hazards models that included p53 staining and other prognostic factors of significance in the univariate analyses revealed p53 to be independently predictive of survival for patients with Stage T3b disease.

CONCLUSIONS

The prognostic value of p53 immunostaining rested with Stage T3b patients. Although no correlations were found with radiation response, p53 positivity in this subgroup was associated with a higher rate of distant metastasis and reduced overall survival. For these patients, p53 negativity would indicate that aggressive local treatment (that is, preoperative radiotherapy and cystectomy) is sufficient, whereas p53 positivity would indicate that multiagent chemotherapy is required because of the increased risk of distant metastasis.