Mononucleotide markers of microsatellite instability in carcinomas of the urinary bladder.

AIMS: To determine the presence of microsatellite instability (MSI) and to assess the expression of the human mismatch repair (MMR) gene products hMLH1 and hMSH2 in primary transitional cell carcinomas (TCCs) of the urinary bladder in relation to clinico-pathological parameters. METHODS: Seventy-two cases of primary TCC were screened for the presence of alterations in MSI markers by molecular techniques and evaluated immunohistochemically for the expression of hMLH1 and hMSH2 proteins. Clinical data were available in 70 cases. The percentage of MSI rose to 16.6%. RESULTS: Reduced (<20%) hMLH1 expression was closely related to the presence of MSI (p=0.0004). Neither MMR proteins nor MSI was associated with grade, stage, papillary status. Clinical outcome analysed as a function of MSI did not show significant differences in terms of both disease-free and overall survival. Reduced hMLH1 expression was a significant predictor of shorter disease-free survival in univariate and multivariate analysis. CONCLUSIONS: The presence of MSI is not related to classical clinico-pathological parameters in TCCs, nor does it appear to be of prognostic significance. hMLH1 was an important indicator for recurrence.

Hypoxia-inducible factor 1alpha/vascular endothelial growth factor axis in astrocytomas. Associations with microvessel morphometry, proliferation and prognosis.

Hypoxia-inducible factor (HIF)-1alpha is a transcription factor that promotes ischaemia-driven angiogenesis. The aim of this study was to determine the relation of HIF-1alpha to vascular endothelial growth factor (VEGF; an important angiogenic molecule in brain tumours), p53 expression, angiogenesis, proliferative potential and clinical outcome in a large series of diffuse astrocytomas. Expression of HIF-1alpha, VEGF, Ki-67 (a proliferation-associated marker) and p53 was determined immunohistochemically in 83 adult patients with supratentorial diffuse astrocytomas. Microvessels, highlighted by means of anti-CD34 immunohistochemistry, were enumerated with computer-assisted image analysis. Although HIF-1alpha and VEGF were expressed in the majority of cases, their levels increased significantly with increasing grade and proliferative potential. HIF-1alpha positively correlated with microvessel counts and VEGF with total vascular area and the presence of rounder vessel sections. There was a positive correlation of VEGF with p53 expression in astrocytomas and anaplastic astrocytomas. In univariate analysis, both VEGF and HIF-1alpha were associated with shortened survival in the entire cohort, but lost significance when grades II/III and grade IV were analysed separately. Multivariate analysis revealed that the combination of HIF-1alpha with grade was a significant prognostic indicator. HIF-1alpha expression may be used to refine the prognostic information provided by grade in patients with diffuse astrocytomas. Its adverse prognostic effect is most likely mediated by hypoxia, the driving force for HIF-1alpha accumulation.

p53 mutations detection in urinary bladder cancer in the Greek population: application of the NIRCA assay.

The aim of the present study was to assess the use of an alternative molecular approach for p53 mutation detection and to investigate the usefulness of p53 as a prognostic indicator in bladder cancer. We applied the NIRCA assay, which consists of two-step PCR amplification, transcription of the amplified sequence, hybridisation of the transcripts and treatment with RNAses which recognizes mismatches due to the presence of mutations. Results of molecular analysis are correlated with immunohistochemical findings, standard clinopathological parameters and survival. p53 mutations were detected in 42.4% of the 66 examined TCCs cases. We could not demonstrate any statistical relationship between the presence of p53 mutation and p53 protein overexpression, and tumor stage or grade. A trend towards higher mutation rate in higher grade tumours was observed, although this failed to reach statistical significance. Despite the observation that the alterations of p53 gene are associated features of aggressive phenotype of transitional cell carcinomas they do not seem to offer additional prognostic information.

Prognostic implications of microvessel morphometry in diffuse astrocytic neoplasms.

Astrocytic brain tumours, particularly malignant astrocytomas, are recognized to be highly vascular neoplasms with potent angiogenic activity. Recent research has shown that quantification of microvessel density (MVD), as a measure of the degree of angiogenesis, constitutes a strong prognostic indicator in patients with astrocytomas. However, the significance of other morphometric aspects of microvessel network has not been tested so far. In this report, histological sections from 70 astrocytomas (grades II to IV), immunostained for CD34, were evaluated by image analysis for the quantification of MVD, total vascular area (TVA), and microvascular branching, as well as several morphometric parameters related to vessel size or shape. Minor axis length increased with grade (P = 0.045) but MVD and TVA presented a peak in grade III (P = 0.033 and P < 0.001, respectively). Size and shape related parameters affected survival in univariate analysis of grade IV and grades II/III, respectively. In multivariate analysis, only branching counts, along with age and grade, were the independent predictors of survival. Although MVD, TVA and branching counts were adversely related to disease-free survival in grades II and III (univariate analysis), only TVA remained statistically significant in multivariate analysis. It is concluded that TVA and branching counts are prognostically more informative than MVD for patients with diffuse astrocytic tumours.

Mitosin and DNA topoisomerase IIalpha: two novel proliferation markers in the prognostication of diffuse astrocytoma patient survival.

The expression of two novel proliferation-associated markers, mitosin and topoisomerase IIalpha (Topo IIalpha), was evaluated immunohistochemically in consecutive paraffin sections from 60 diffuse astrocytomas (grades 2 to 4) in relation to clinicopathologic parameters, proliferating cell nuclear antigen (PCNA) and Ki-67 (MIB-1) expression and survival. The percentage of mitosin and Topo IIalpha-positive cells (LI) increased with grade and Ki-67 LI, but could not discriminate between grade 3 on the one hand and grades 2 or 4 on the other hand. In 51% of cases, Ki-67 LI exceeded Topo IIalpha LI, especially within grade 4. Topo IIalpha and mitosin expression was adversely related to overall and disease-free survival in the entire cohort and in grades 2/3. However, only Topo IIalpha LI affected disease-free survival in grade 4 tumors. Multivariate analysis selected only mitosin LI along with the age of the patient, as the independent parameters predicting overall survival, whereas Topo IIalpha emerged as the single independent predictor of disease-free survival. It is concluded that the proliferative potential of astrocytomas, as measured by mitosin and Topo IIalpha immunostaining, conveys useful prognostic information, in addition to that obtained by standard clinicopathologic parameters.

Morphometric microvascular characteristics predict prognosis in superficial and invasive bladder cancer.

Recent research has shown that neovascularization, quantitated by microvessel density (MVD), constitutes a strong prognostic indicator in patients with invasive urothelial carcinomas. These studies, however, have focused only on MVD as the only factor reflecting angiogenesis in transitional-cell carcinomas (TCCs). The objective of this report was to evaluate multiple morphometric microvascular characteristics besides MVD in superficial and muscle-invasive TCCs separately, to provide a better approach to the relationship between angiogenesis, clinicopathological parameters, and prognosis. Histologic sections from 115 TCCs [35 superficial (T1) and 80 muscle-invasive] were immunostained for CD31 and evaluated using image analysis for the quantitation of MVD, area, total vascular area, major axis length, minor axis length, perimeter, compactness, shape factor, and Feret diameter. Patients were followed-up until death (n=31) or for an average of 42.2 months (median 38.5 months). MVD increased with progressing T category (P=0.049) but area (P=0.033), major axis length (P=0.022), perimeter (P=0.043), and Feret diameter (P=0.042) were highest in T2 tumors. Area was the single independent predictor of adverse significance in T1 TCCs, whereas for muscle-invasive tumors, survival was independently predicted by MVD. Regarding disease-free survival in superficial tumors, the single significant independent parameter was compactness, whereas area was an independent favorable indicator of disease-free survival for patients with invasive TCCs. It is concluded that the prognostic significance of neovascularization is better assessed by area and shape-related morphometric characteristics, whereas MVD becomes influential only with regard to overall survival of patients with invasive tumors.

Detection of apoptotic cells in archival tissue from diffuse astrocytomas using a monoclonal antibody to single-stranded DNA.

Precise quantitation of apoptotic cells in gliomas is necessary to determine the role of apoptosis in tumour growth, prognosis, and treatment. This study investigated the incidence of baseline apoptosis in relation to proliferation status, p53 expression, standard clinicopathological parameters, and outcome, in a series of 61 patients with diffuse cerebral astrocytomas. Apoptotic fractions were quantified immunohistochemically by means of a novel monoclonal antibody recognizing exposed single-stranded (ss) regions in the DNA of apoptotic cells during heating. Proliferative activity was expressed as the percentage of Ki-67-positive cells. Tissues consisted of primary formalin-fixed, paraffin-embedded astrocytoma specimens. The apoptotic index (AI) increased with grade, proliferative activity, and p53 expression. Increased AI tended to be accompanied by a shortened overall and disease-free survival in univariate analysis in glioblastoma multiforme and astrocytoma/anaplastic astrocytoma, respectively. Multivariate analysis demonstrated that increased AI was an independent predictor of adverse significance in overall and disease-free survival. These results implicate apoptotic rate in astrocytoma aggressiveness and show that the assessment of apoptotic potential by means of anti-ssDNA monoclonal antibody provides valuable prognostic information independently of standard parameters or tumour proliferation status.

Prognostic implications of aberrations in p16/pRb pathway in urothelial bladder carcinomas: a multivariate analysis including p53 expression and proliferation markers.

OBJECTIVE: To assess the prognostic value of the expression of two negative regulators of the cell cycle, namely CDKN2/INK4a gene product (p16) and retinoblastoma gene product (pRb), in urinary bladder cancer in relation to clinicopathological parameters, proliferative fraction and p53 protein accumulation. METHODS: Paraffin sections from 139 patients with urothelial carcinomas were stained immunohistochemically with antibodies to p16 (F12), pRb (PMG3-245), p53 (DO1), PCNA (PC10) and Ki-67 (MIB-1). RESULTS: Diminished p16 and pRb expression occurred in 29 and 74% of cases, respectively, being associated with advanced stage but not with histological grade, papillary status or proliferation rate. In most cases (53%) with some fault in the p16/pRb pathway, only one gene was affected. A double-negative p16/pRb phenotype was comparatively uncommon (25%) and was usually seen in T3-T4 tumours. In survival analysis (either univariate or multivariate) aberrant p16 expression was an adverse prognostic parameter only in T3-T4 tumours. In contrast, the abnormal p16/pRb and p53/p16 phenotypes were linked to a diminished overall and disease-free survival (univariate analysis); p53/p16 abnormal expression was also found to be an independent predictor of reduced survival in muscle-invasive tumours, while proliferation markers were the only parameters with independent significance in superficial (Ta-T1) tumours. CONCLUSION: Our results suggest that lack of p16 immunoexpression, when combined with p53 accumulation, plays an important role in determining the clinical outcome in muscle-invasive urothelial carcinomas.

WAF1/p21 protein expression is an independent prognostic indicator in superficial and invasive bladder cancer.

The inhibitor of cyclin-dependent kinases WAF1 gene product p21 is able to arrest mammalian cell cycle by mediating p53 and other factors. The prognostic value and interrelationships between p21 expression and various parameters in bladder cancer have not been fully elucidated. We retrospectively investigated the immunohistochemical expression of p21 protein in consecutive paraffin sections from 131 transitional cell carcinomas (TCCs) and related it to p53 protein expression, clinicopathologic parameters, proliferative fraction, and survival. Positivity was displayed in 45% of cases, among which one fourth was accompanied by p53 accumulation. p21 expression was statistically related to advanced T category. No association was shown between p21 and p53 or proliferation rate. Low grade invasive TCCs tended to be more often p21 positive than high grade invasive TCCs. Most superficial tumors displayed neither p21 nor p53 expression, whereas the combined phenotypes p53/p21+ and p53+/p21- predominated among invasive tumors. P21 labeling index emerged by multivariate analysis as the single independent indicator of shortened overall (P = 0.0294) and disease-free (P = 0.0414) survival in superficial TCCs. Conversely, in invasive tumors, loss of p21 expression was a predictor of shortened disease-free survival (P = 0.0234) and was associated with poor outcome when accompanied by p53 accumulation (P = 0.0033). In conclusion, our results indicate that p21 activation occurs early in tumorigenesis, appears associated with invasiveness, and is capable of cell cycle control in TCCs mostly through p53-dependent pathways. Finally, p21 expression, alone or in combination with p53 and irrespective of other clinicopathologic parameters, plays distinct roles in determining clinical outcome in superficial and invasive tumors, suggesting that urothelial bladder cancer represents two different diseases.

Cell cycle regulators in bladder cancer: a multivariate survival study with emphasis on p27Kip1.

Cyclin-dependent kinase inhibitors (CKIs) prevent cyclin-dependent kinases from phosphorylating critical substrates such as retinoblastoma gene protein (pRb), hence blocking the cascade of events leading to cell proliferation. Currently, the list of CKIs includes p21WAF1/Cip1, p27Kip1, p57Kip2 (the Cip/Kip family), p15/ INK4b, p16/INK4a, p18/INK4c, and p19/INK4d (the INK4 family). Among them, p27 plays a crucial role linking extracellular growth-regulatory signals to progression to or exit from the cell cycle. Unlike p53, p16, and Rb, mutations in Kip1 and WAF1 genes are distinctly rare in bladder cancer. We analyzed immunohistochemically the expression of p27 and other interacting G1 proteins (ie, p21, p16, pRb, p53) in 120 consecutive cases of transitional cell carcinomas (TCCs) and related it to proliferation rate, clinicopathologic parameters, and survival. p27 levels were significantly higher in low-grade (P = .001), superficial (Ta-T1) (P = .001), papillary (P < .001), and slowly proliferating TCCs (rs = -0.235, P = .05). p27 also positively correlated with p16 expression (rs = 0.212, P = .05). In univariate analysis, decreased p27 expression was associated with poor overall (P = .0109) and postrelapse (P = .0344) survival, especially if combined to increased Ki-67 expression (P = .0004 and P = .036, respectively). Furthermore, in multivariate analysis, Ki-67/p27 status had the strongest bearing on the overall survival of muscle-invasive TCCs (P = .0019). Our results indicate that low p27 expression is more common in poorly differentiated muscle-invasive TCCs and is a major player in cell cycle control in these neoplasms. More importantly, the combined Ki-67/p27 expression provides prognostic information beyond that provided by conventional parameters or other cell cycle-related proteins, concerning overall survival in muscle-invasive TCCs.

Prognostic relevance of apoptotic cell death in non-Hodgkin's lymphomas: a multivariate survival analysis including Ki67 and p53 oncoprotein expression.

AIMS: To evaluate the independent prognostic value of apoptotic versus proliferative fractions in a series of 92 patients with non-Hodgkin's lymphomas (NHL). METHODS AND RESULTS: Apoptotic fractions were quantified by use of the TdT (terminal deoxynucleotidyl-transferase)-mediated in-situ end-labelling technique (TUNEL), the percentage of positive cells constituting the apoptotic index (AI). Proliferative rate was expressed as percentage of Ki67 positive cells (Ki67 LI). Tissues were also stained for p53 protein with the DO-1 antibody. Patients were followed up until death (n = 33) or for an average of 63 months (n = 56). AI increased with malignancy grade and proliferative activity but was not related to location, cell of origin, clinical stage, bone marrow involvement and p53 expression. In multivariate analysis, overall survival was independently influenced by grade, stage, p53 LI and chemotherapy. The independent predictors of disease-free survival were Ki67 LI location and chemotherapy. AI turned out to be the only independent (negative) predictor of post-relapse survival. On the other hand, a low Ki67 LI increased the risk of relapse (logistic regression analysis) whereas a low p53 LI increased the probability of complete response. CONCLUSIONS: Our results suggest that the combined assessment of apoptotic fraction, proliferative rate and p53 expression may provide important prognostic information independent of other clinicopathological parameters in NHL.

Expression of retinoblastoma gene product and p21 (WAF1/Cip 1) protein in gliomas: correlations with proliferation markers, p53 expression and survival.

Using immunohistochemistry we evaluated the expression of two negative regulators of the cell cycle, the retinoblastoma gene product (pRb) and the WAF1/Cip1 gene product (p21), in consecutive paraffin sections from 54 gliomas (49 astrocytomas and 5 oligodendrogliomas) and related it to clinicopathological parameters, proliferative fraction, p53 expression and survival. Survival analysis was restricted to the group of diffuse astrocytomas (48 patients). pRb expression did not correlate with histological type, grade or p53 expression, while a moderately strong correlation existed between pRb expression and the percentages of proliferating cell nuclear antigen (PCNA) and MIB-1-positive cells. In 30% of cases we observed diminished pRb expression (i.e., a low pRb/Ki-67 ratio), irrespective of grade or histological type. p21 protein was elevated in 50% of cases, especially within the higher grades. The percentage of p21-positive cells was not related to histological type or grade but correlated loosely with PCNA and pRb expression. A p53-negative/p21-negative phenotype was characteristic of oligodendrogliomas and low-grade astrocytomas, whereas the p53-positive/p21-positive, p53-positive/p21-negative and p53-negative/p21-positive phenotypes were almost equally distributed among high-grade tumors. In survival analysis (either univariate or multivariate) diminished pRb expression was not a statistically significant prognostic indicator. In contrast, p21 expression emerged as an important indicator of shortened disease-free survival, in both univariate and multivariate analyses. Moreover, the double-positive p53/p21 phenotype tended to be associated with a shorter overall survival. Our results suggest that Rb gene deregulation does not significantly affect prognosis but p21 expression may play an important role in disease-free survival of astrocytoma patients.

MDM2 and p53 expression in gliomas: a multivariate survival analysis including proliferation markers and epidermal growth factor receptor.

p53 and the murine double minute 2 (MDM2) oncoprotein expression was evaluated in paraffin-embedded tissue from 61 patients with central nervous system gliomas (53 astrocytomas and eight oligodendrogliomas) and related to proliferation-associated markers [i.e. proliferating cell nuclear antigen (PCNA), Ki-67 and nuclear organizer regions (NORs)] and epidermal growth factor receptor (EGFR). We used the monoclonal antibodies PC-10, MIB-1, DO-1, 1B1O and EGFR 113 and the colloid silver nitrate (AgNOR) technique. MDM2 and p53 were co-expressed in 28% of cases. A p53-positive/MDM2-negative phenotype was observed in 15% and a p53-negative/MDM2-positive phenotype in 20% of cases. There was a positive correlation of p53 and MDM2 expression with grade and proliferation indices. Univariate analysis in the group of diffuse astrocytomas showed that older age, high histological grade, high PCNA labelling index (LI) and high AgNOR score were associated with reduced overall survival (P < 0.05). p53 LI, Ki-67 LI, AgNOR score, tumour location and grade influenced disease-free survival (P < 0.05), whereas the only parameters affecting post-relapse survival were histological grade and Ki-67 LI (P < 0.1). Multivariate analysis revealed that age, radiotherapy, PCNA LI and p53 LI were the independent predictors of overall survival. p53 LI, Ki-67 LI, MDM2 LI, EGFR LI, grade and type of therapy were independent predictors of disease-free survival, and grade was the only independent predictor of post-relapse survival. Our results indicate that p53 LI and MDM2 LI, EGFR expression as well as proliferation markers (PCNA and Ki-67) are useful indicators of overall and disease-free survival in diffuse astrocytoma patients.

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.

Prognostic significance of proliferating cell nuclear antigen (PCNA) expression in gliomas.

The relationship between proliferating cell nuclear antigen (PCNA) expression and various clinicopathological indices (age, sex, tumour location, histological type and grade and treatment) and post-operative survival were studied in patients with central nervous system gliomas using univariate and multivariate analysis. The expression of PCNA (PC10 score) was examined immunohistochemically using the monoclonal antibody PC10 on paraffin sections from 45 cases. Univariate analysis showed that a high PC10 score as well as older age, high histological grade and the histological type (astrocytoma) were associated with reduced survival. However, multivariate analysis revealed that only PC10 score and histological type had independent prognostic significance. The most important feature influencing PC10 score was the tumour grade. Regarding the patients who relapsed, the survival from the time of original diagnosis was related to the relapse-free period, while the PC10 score of the primary tumour emerged as the only independent predictor of survival following the first recurrence. These results indicate that PCNA expression is an independent prognostic indicator in CNS gliomas.

Assessment of proliferating-cell nuclear antigen immunostaining in soft-tissue tumours: relationship to histological grade and mitotic activity.

The proliferative activity in 70 cases of soft-tissue tumours was estimated immunohistochemically using the monoclonal antibody PC-10, which recognizes proliferating-cell nuclear antigen (PCNA) in paraffin sections. The PCNA index (i.e. the percentage of positive neoplastic nuclei) and to a lesser degree the PCNA count (i.e. the number of positive neoplastic nuclei per ten high-power fields) positively correlated with the malignancy grade (PCNA index: P < 0.001; PCNA count: P < 0.01). However, the range of values of PCNA index and PCNA count was similar between benign and grade I tumours. A statistically significant positive correlation was also established between PCNA index and PCNA count on the one hand and mitotic count on the other, but the correlation coefficient was low (r = 0.351, P < 0.01, and r = 0.290, P < 0.05 respectively). These results indicate that PCNA immunostaining may successfully be used as an adjunct to the conventional histopathological parameters in assessing the malignancy grade in soft-tissue tumours although it is of limited value in distinguishing between benign and grade I tumours.

Proliferating cell nuclear antigen and nucleolar organizer regions in CNS tumors: correlation with histological type and tumor grade. A comparative study of 82 cases on paraffin sections.

We investigated the expression of proliferating cell nuclear antigen (PCNA) and the number of nucleolar organizer regions (NORs) in 82 cases of CNS tumors. PCNA is a nuclear protein maximally elevated in the S phase of the cell cycle and recognized immunohistochemically in paraffin sections by the monoclonal antibody PC-10. On the other hand, NORs are loops of DNA that carry the rRNA genes and can be demonstrated in paraffin sections using an argyrophilic method (AgNORs). The present study shows a significant correlation of PCNA index and of AgNOR number with the histological grade (PCNA: I versus II, p < 0.01; II versus III, p < 0.01; and III versus IV, p < 0.05; AgNORs: I versus II, p < 0.001; II versus III, p < 0.05; and III versus IV, p < 0.001). Higher values of PCNA index (0.01 < p < 0.05) were found in recurrent tumors. Metastatic carcinomas were characterized by high PCNA indices and AgNOR numbers, similar to grade IV tumors, whereas in CNS lymphomas the malignancy grade was reflected in PCNA indices and AgNOR numbers. A wide range of PCNA and AgNOR values has been observed within each histological type and grade, probably reflecting variations in the biological behavior, but little overlap in PCNA values was present between grades II and III. The latter finding might be of importance in distinguishing between low- and high-grade CNS tumors. The linear regression coefficient between PCNA index and AgNOR number was excellent (0.91). We suggest that PCNA and AgNORs may be successfully applied in routine material to assess the growth potential of CNS tumors. Their prognostic value, however, must be validated with clinical studies.

Comparative assessment of proliferating cell nuclear antigen immunostaining and of nucleolar organizer region staining in transitional cell carcinomas of the urinary bladder. Correlation with other conventional prognostic pathologic parameters.

The expression of two cell proliferation indices, the proliferating cell nuclear antigen (PCNA), using the monoclonal antibody PC-10 in the immunoperoxidase method, and the nucleolar organizer regions (NORs), using the colloid silver nitrate staining technique, was assessed in formalin-fixed paraffin-embedded material of 50 transitional cell urinary bladder carcinomas. A relationship was found between the histologic grade and each of the two indices used. A significant difference was observed, particularly between carcinomas of grade II and III (p < 0.001). A relationship was also demonstrated between each of PC-10 and AgNOR scores and the clinical stage, but it was attributed mostly to the close correlation of the latter with the histologic grade of these tumors. The linear correlation coefficient between PC-10 and AgNOR scores was 0.757 (p < 0.001). Our results suggest that PC-10 and AgNOR scores may be important prognostic indices in urinary bladder cancer.