Nomogram Predicting Bladder Cancer-specific Mortality After Neoadjuvant Chemotherapy and Radical Cystectomy for Muscle-invasive Bladder Cancer: Results of an International Consortium.

BACKGROUND: Cisplatin-based neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) is associated with improved overall and cancer-specific survival. The post-NAC pathological stage has previously been reported to be a major determinant of outcome. OBJECTIVE: To develop a postoperative nomogram for survival based on pathological and clinical parameters from an international consortium. DESIGN, SETTING, AND PARTICIPANTS: Between 2000 and 2015, 1866 patients with MIBC were treated at 19 institutions in the USA, Canada, and Europe. Analysis was limited to 640 patients with adequate follow-up who had received three or more cycles of NAC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: A nomogram for bladder cancer-specific mortality (BCSM) was developed by multivariable Cox regression analysis. Decision curve analysis was used to assess the model's clinical utility. RESULTS AND LIMITATIONS: A total of 640 patients were identified. Downstaging to non-MIBC (ypT1, ypTa, and ypTis) occurred in 271 patients (42 %), and 113 (17 %) achieved a complete response (ypT0N0). The 5-yr BCSM was 47.2 % (95 % confidence interval [CI]: 41.2-52.6 %). On multivariable analysis, covariates with a statistically significant association with BCSM were lymph node metastasis (hazard ratio [HR] 1.90 [95% CI: 1.4-2.6]; p < 0.001), positive surgical margins (HR 2.01 [95 % CI: 1.3-2.9]; p < 0.001), and pathological stage (with ypT0/Tis/Ta/T1 as reference: ypT2 [HR 2.77 {95 % CI: 1.7-4.6}; p < 0.001] and ypT3-4 [HR 5.9 {95 % CI: 3.8-9.3}; p < 0.001]). The area under the curve of the model predicting 5-yr BCSM after cross validation with 300 bootstraps was 75.4 % (95 % CI: 68.1-82.6 %). Decision curve analyses showed a modest net benefit for the use of the BCSM nomogram in the current cohort compared with the use of American Joint Committee on Cancer staging alone. Limitations include the retrospective study design and the lack of central pathology. CONCLUSIONS: We have developed and internally validated a nomogram predicting BCSM after NAC and radical cystectomy for MIBC. The nomogram will be useful for patient counseling and in the identification of patients at high risk for BCSM suitable for enrollment in clinical trials of adjuvant therapy. PATIENT SUMMARY: In this report, we looked at the outcomes of patients with muscle-invasive bladder cancer in a large multi-institutional population. We found that we can accurately predict death after radical surgical treatment in patients treated with chemotherapy before surgery. We conclude that the pathological report provides key factors for determining survival probability.

Concomitant CIS on TURBT does not impact oncological outcomes in patients treated with neoadjuvant or induction chemotherapy followed by radical cystectomy.

BACKGROUND: Cisplatin-based neoadjuvant chemotherapy (NAC) for muscle invasive bladder cancer improves all-cause and cancer specific survival. We aimed to evaluate whether the detection of carcinoma in situ (CIS) at the time of initial transurethral resection of bladder tumor (TURBT) has an oncological impact on the response to NAC prior to radical cystectomy. PATIENTS AND METHODS: Patients were identified retrospectively from 19 centers who received at least three cycles of NAC or induction chemotherapy for cT2-T4aN0-3M0 urothelial carcinoma of the bladder followed by radical cystectomy between 2000 and 2013. The primary and secondary outcomes were pathological response and overall survival, respectively. Multivariable analysis was performed to determine the independent predictive value of CIS on these outcomes. RESULTS: Of 1213 patients included in the analysis, 21.8% had concomitant CIS. Baseline clinical and pathologic characteristics of the 'CIS' versus 'no-CIS' groups were similar. The pathological response did not differ between the two arms when response was defined as pT0N0 (17.9% with CIS vs 21.9% without CIS; p = 0.16) which may indicate that patients with CIS may be less sensitive to NAC or ≤ pT1N0 (42.8% with CIS vs 37.8% without CIS; p = 0.15). On Cox regression model for overall survival for the cN0 cohort, the presence of CIS was not associated with survival (HR 0.86 (95% CI 0.63-1.18; p = 0.35). The presence of LVI (HR 1.41, 95% CI 1.01-1.96; p = 0.04), hydronephrosis (HR 1.63, 95% CI 1.23-2.16; p = 0.001) and use of chemotherapy other than ddMVAC (HR 0.57, 95% CI 0.34-0.94; p = 0.03) were associated with shorter overall survival. For the whole cohort, the presence of CIS was also not associated with survival (HR 1.05 (95% CI 0.82-1.35; p = 0.70). CONCLUSION: In this multicenter, real-world cohort, CIS status at TURBT did not affect pathologic response to neoadjuvant or induction chemotherapy. This study is limited by its retrospective nature as well as variability in chemotherapy regimens and surveillance regimens.

Fluid intake, genetic variants of UDP-glucuronosyltransferases, and bladder cancer risk.

BACKGROUND: Results of studies of fluid consumption and its association with bladder cancer have been inconsistent. Few studies have considered modification effects from genetic variants that may interact with the type of consumed fluids. UDP-glucuronosyltransferases (UGTs), which are membrane-bound conjugating enzymes, catalyse the transformation of hydrophobic substrates to more water-soluble glucuronides to facilitate renal or biliary excretion. Whether genetic variants in UGTs could modulate the association between fluid intake and bladder cancer has not been studied. METHODS: We conducted a case-control study with 1007 patients with histopathologically confirmed bladder cancer and 1299 healthy matched controls. Fluid intake and epidemiologic data were collected via in-person interview. Multivariate unconditional logistic regression was used to estimate odds ratios (ORs) and the 95% confidence intervals (95% CI). RESULTS: After adjustment for potential confounders, high quantity of total fluid intake (> or =2789 vs. <1696 ml per day) conferred a 41% increased risk of bladder cancer (OR=1.41; 95% CI=1.10-1.81). Specific fluids such as regular soft drinks and decaffeinated coffee were also associated with increased risks, whereas tea, wine, and liquor were associated with decreased risks. Among 83 single-nucleotide polymorphisms in the UGT gene family, 18 were significantly associated with bladder cancer risk. The most significant one was rs7571337, with the variant genotype conferring a 29% reduction in risk (OR=0.71; 95% CI=0.56-0.90). CONCLUSIONS: Total and specific fluid intakes are associated with bladder cancer risk in the study population and that genetic variants of UGT genes could modulate the effects. These results facilitate identification of high-risk individuals and have important implications in bladder cancer prevention.

Controversies in ilioinguinal lymphadenectomy.

Patients with penile cancer who are proven to have negative inguinal lymph nodes have an excellent prognosis. Furthermore, patients with small-volume inguinal node involvement can often be cured by surgery alone. Lymphadenectomy has clear survival benefits for patients when applied to those with lymph node metastasis. However, the current morbidity of the standard technique of lymphadenectomy is an impediment to its universal application, and innovative strategies to reduce the morbidity of staging/treatment that do not compromise oncologic control must be developed and standardized. The optimal integration of multimodality therapy to improve survival in advanced disease will occur only through collaborative studies between centers with significant patient volume, which would be facilitated through the development of regional referral centers.

E-cadherin promoter polymorphism (C-160A) and risk of recurrence in patients with superficial bladder cancer.

Tumor recurrence is a hallmark of superficial bladder cancer. Currently, a molecular marker for bladder cancer recurrence is lacking. E-cadherin plays an important role in epithelial development and in the establishment and maintenance of cell-cell adhesion and tissue architecture. The purpose of this study is to investigate the association of an E-cadherin promoter polymorphism (CDH1c-160a) with the risk of bladder cancer recurrence. This study included 302 patients with superficial bladder cancer. Genomic DNA was extracted from peripheral blood lymphocytes and genotyping was performed using Taqman assay. Clinical data were collected by medical chart review. Cox proportional hazard model was used to estimate the hazard ratios (HRs) associated with genotypes while adjusting for age, gender, smoking status, tumor stage and grade where appropriate. During a median follow-up of 27.65 months, 151 patients experienced disease recurrence. Subsequent analyses were restricted to Caucasians only due to the small sample size of other ethnic groups (13 in recurrence group and 15 in non-recurrence group). Among the 274 Caucasian patients, 138 developed recurrence during the same length of follow-up time. In Caucasian patients, having at least one variant A allele conferred a 32% reduction in recurrence risk (adjusted HR: 0.68; 95% CI: 0.48-0.96). The median recurrence-free survival for patients carrying at least one variant A allele was significantly longer than that for patients with a homozygous CC genotype (40.4 vs 12.5 months, p=0.04). Our findings suggest that the E-cadherin promoter polymorphism may be a valuable molecular marker for bladder cancer recurrence.

Efficacy of a single intravesical treatment with Ad-IFN/Syn 3 is dependent on dose and urine IFN concentration obtained: implications for clinical investigation.

There is a need to improve the treatment of superficial bladder cancer. One area which holds promise is intravesical gene therapy. Recently, studies undertaken by us have shown that marked tumor regression of bladder cancers occurred after two daily intravesical administrations of an adenovirus encoding human interferon alpha (Ad-IFNalpha) using a mouse superficial bladder cancer model in which human bladder tumors are growing. A dose of 1 x 10(11) particles/ml (P/ml) was used along with 1 mg/ml of Syn3, a gene transfer-enhancing agent. Since clinical studies are being planned using this approach, it became critical to determine if one exposure and lower particle number could be equally effective. We report that indeed a single dose of Ad-IFNalpha in Syn3 at doses of 1 x 10(10)-1 x 10(11) P/ml is highly effective in reducing the size of the tumors, whereas 1 x 10(9) P/ml was not. Efficacy was also correlated with the level of IFN produced in the urine after treatment. Based on the results of the present studies, a Phase I trial is being planned for superficial bladder cancer, which will involve a single initial treatment with Ad-IFNalpha/Syn3 and measurement of IFN in the urine over time as an indicator of adequate gene transfer and expression.

Novel approaches with targeted therapies in bladder cancer. Therapy of bladder cancer by blockade of the epidermal growth factor receptor family.

The improved understanding of the molecular biology of urothelial malignancies is helping to define the role of new targets and prognostic indices that can direct the most appropriate choice of treatment for advanced disease. Many human tumors express high levels of growth factors and their receptors that can be used as potential therapeutical targets. Tyrosine-kinase receptors, including many growth factor receptors such the receptors for epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and Her2/neu, have been found overexpressed in urothelial tumors. For many of these growth factor receptors, the degree of expression has been associated with the progression of cancer and a poor prognosis. Among the best studied growth factor receptors are the two members of EGF receptor familiy EGFr (ErbB-1), and Her2/neu (ErbB-2). Several preclinical studies in bladder cancer models, have confirmed that systemic administration of growth factor inhibitors inhibits the growth and metastasis of human transitional cell carcinoma established in the bladder wall of athymic nude mice. Additional studies indicate that therapy with EGFR inhibitors enhances the activity of conventional cytoreductive chemotherapeutic agents, in part by inhibiting tumor cell proliferation, angiogenesis, and inducing apoptosis. Novel targeted therapy hold promise to improve the current results of bladder cancer treatment. Based on the success seen with anti-HER2 monoclonal antibodies (Herceptin) and the promising results with EGFR targeted agents (IMC-C225 Cetuximab, ZD1389 Iressa, OSI-774 Tarceva, GW 57016) in other tumor types, and based on the results obtained in preclinical models, there is a great interest in assessing these agents in patients with bladder cancer. Several trials are now ongoing testing these new agents alone or in combination with chemotherapy in bladder cancer patients. The integration of these newer biologic agents, probably to supplement rather than to supplant chemotherapeutic drugs, should be a primary direction of research with the objective to interfere with multiple aspects of bladder cancer progression. However, the value of integration of biologically targeted agents into combined modality treatment for patients with bladder cancer has still to be proven.

Treatment with low-dose interferon-alpha restores the balance between matrix metalloproteinase-9 and E-cadherin expression in human transitional cell carcinoma of the bladder.

Tumor invasion and metastasis are regulated by the expression of genes such as E-cadherin, which regulates cell adhesion, and matrix metalloproteinase-9 (MMP-9), which alters the integrity of the extracellular matrix. Both up-regulation of MMP-9 and down-regulation of E-cadherin correlate with bladder cancer metastasis. The purpose of this study was first to determine whether an imbalance between MMP-9 and E-cadherin expression correlates with metastasis from human transitional cell carcinoma (TCC) of the bladder after therapy with neoadjuvant chemotherapy and radical cystectomy and then to determine whether treatment of human TCC xenografts growing in nude mice with interferon (IFN)-alpha would restore this balance, thereby limiting tumor invasion and metastasis. We used in situ hybridization to evaluate the expression of several metastasis-related genes, including MMP-9 and E-cadherin, in paraffin-embedded biopsy specimens from 55 patients with muscle-invasive TCC treated with neoadjuvant methotrexate, vinblastine, doxorubicin, and cisplatin chemotherapy and radical cystectomy. By multivariate analysis, an MMP-9:E-cadherin ratio of >1.8 was an independent prognostic factor for disease progression. In vitro incubation of an IFN-resistant, highly metastatic human TCC cell line, 253J B-V(R) with noncytostatic concentrations of IFN-alpha down-regulated the activity of MMP-9, up-regulated E-cadherin, and inhibited in vitro invasion. 253J B-V(R) cells were implanted into the bladders of athymic nude mice. Systemic therapy with IFN-alpha (10,000 units s.c. daily) decreased the expression of MMP-9, increased expression of E-cadherin, reduced tumor volume, and inhibited metastasis. The MMP-9:E-cadherin ratio was 4.5 in untreated controls and 1.1 after IFN-alpha treatment. Moreover, systemic low-dose daily IFN-alpha potentiated the efficacy of paclitaxel. These studies indicate that in addition to its antiproliferative and antiangiogenic effects, IFN-alpha limits tumor invasion by restoring the normal balance between MMP-9 and E-cadherin and enhances the activity of systemic chemotherapy.

Adenoviral-mediated gene therapy of human bladder cancer with antisense interleukin-8.

We previously demonstrated the importance of interleukin-8 (IL-8) as a mediator of angiogenesis, tumorigenicity, and metastasis of transitional cell carcinoma (TCC) of the bladder. In the present study, we evaluated the feasibility of adenoviral mediated antisense IL-8 gene transfer (Ad IL-8-AS) as therapy for established TCC. In vitro, Ad IL-8-AS inhibited endothelial cell proliferation and enhanced endothelial cell apoptosis. The highly metastatic human TCC cell line 253J B-V(R) was implanted into the subcutis of athymic nude mice, and intralesional therapy with Ad IL-8-AS commenced when the tumors reached a diameter between 5 and 7 mm. Tumor growth was significantly inhibited compared with therapy in controls (saline and beta-galactosidase adenovirus). Ad IL-8-AS therapy decreased the in vivo expression of IL-8 and matrix metalloproteinase type 9 (MMP-9), reduced microvessel density, and enhanced endothelial cell apoptosis. These results indicate that Ad IL-8-AS therapy targets both tumor cells and host endothelial cells resulting in endothelial cell apoptosis and significant inhibition of tumor growth.

Radical cystectomy for invasive bladder cancer in the octogenarian.

The incidence of bladder cancer increases with age. As the population lives longer, an increasing number of patients 80 years of age or older will develop invasive bladder cancer. In this study, we reviewed the outcome of 33 patients age 80 years or older treated with radical cystectomy and ileal conduit urinary diversion. Five patients received neoadjuvant chemotherapy, and 2 had salvage cystectomy after failure of external beam radiation therapy. The median age was 82 years, and the median hospital stay was 12 days. There were no perioperative deaths. Twenty-seven complications occurred in 20 patients (60.6%), of which 17 were minor (63%) and 10 were major (37%). There was no difference in the rate of complications in patients receiving neoadjuvant treatment compared to the group treated with cystectomy alone. The median survival was 3.5 years. Our results demonstrate that radical cystectomy and ileal conduit urinary diversion should not be withheld from patients on the basis of age.

The role of angiogenesis in prostate and other urologic cancers: a review.

Angiogenesis is a process critical to both tumour growth and metastasis. It is a dynamic integrated process involving basement membrane degradation, endothelial cell proliferation and migration, and capillary tubule formation. Under normal circumstances, the microvasculature is maintained in a quiescent state. The acquisition of the angiogenic phenotype depends on the outcome of stimulatory and inhibitory regulation by the tumour and its microenvironment. There are markers of angiogenesis that potentially could provide prognostic information in addition to that gained from conventional clinicopathologic data, and antiangiogenic therapy for urologic cancers has potential advantages over current therapeutic strategies. Promising preclinical studies have led to the initiation of phase I studies of antiangiogenic therapy in combination with chemotherapy, which may lead to novel treatments for urologic malignant tumours and may identify new intermediate markers for the response to therapy.

Expression levels of genes that regulate metastasis and angiogenesis correlate with advanced pathological stage of renal cell carcinoma.

We examined the expression levels of a number of metastasis-related genes to determine the relationship of these levels to the development of metastasis in renal cell carcinoma. Gene expression was examined in 46 formalin-fixed, paraffin-embedded, archival specimens of primary organ-confined, clear-cell, renal cell carcinoma from patients who had undergone radical nephrectomy. Twenty samples were from patients who did not have metastasis after a median of 48 months; 26 were from patients with either synchronous or metachronous metastases. Microvessel density was assessed by anti-CD-34 immunohistochemical analysis. The expression levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), matrix metalloproteinases (MMP)-2 and -9, and E-cadherin were examined at the periphery of the tumor by a colorimetric in situ mRNA. The expression levels of bFGF, VEGF, IL-8, MMP-2, and MMP-9 were significantly higher in primary renal tumors from patients with either synchronous or metachronous metastases than those who were disease-free at a median of 48 months of follow-up. Multivariate analysis of disease-free survival showed that the ratio of MMP-9 to E-cadherin (P = 0.012) and the expression level of bFGF expression (P = 0.045), were independent predictors for the development of metastases. The expression levels of bFGF, VEGF, and IL-8 did not correlate with microvessel density, which in itself was not a significant predictor of progression (P = 0.21). In summary, expression levels of genes that regulate metastasis angiogenesis can predict the metastatic potential in individual patients with organ-confined clear-cell renal carcinoma.

Differential expression of progression-related genes in the evolution of superficial to invasive transitional cell carcinoma of the bladder.

It is generally accepted that there are dichotomous biologic pathways that lead to the development of either: i) superficial papillary (Ta) transitional cell carcinoma (TCC) or ii) precursor lesions to muscle-invasive (CIS, T1) TCC and muscle-invasive (> or =T2) TCC. We investigated the expression of several progression-related genes to characterize the phenotype of these tumors within these divergent developmental pathways. Using a colorimetric in situ hybridization technique, we examined the expression of mRNAs of several progression-related genes in archival, pathologic specimens from 77 patients with bladder TCC. These genes included basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), interleukin (IL)-8, matrix metalloproteinase (MMP)-9, and epidermal growth factor receptor (EGFR). Relative gene expression was quantified using image analysis. Gene expression was normalized using poly (dT) and the expression of each factor in a panel of specimens of normal urothelium. Patients were stratified according to disease stage, and the level of gene expression among the stratified groups was compared. VEGF, bFGF, IL-8, and MMP-9 expression was increased in muscle-invasive compared with superficial papillary tumors, (p<0.05) and VEGF expression was increased in muscle-invasive tumors compared with CIS specimens (p<0. 05). bFGF, IL-8, and EGFR expression was increased in CIS specimens compared with superficial papillary tumors (p<0.05). The pattern of expression of bFGF, VEGF, IL-8, MMP-9, and EGFR represent the divergent developmental pathways in the pathogenesis of bladder TCC, which characterizes superficial or invasive bladder cancer. bFGF, IL-8, and EGFR appear to be upregulated in early precursor lesions (CIS), whereas VEGF appears to be upregulated at later stages in the development of muscle-invasive TCC.

Gene therapy for superficial bladder cancer.

In this review, the basics of gene therapy and the strategies to increase the therapeutic effect of gene therapy for superficial bladder cancer are discussed. Strategies considered in detail are modification of the structure of vectors, modification of the promoters of viral vectors and the timing and route of vector administration. Although all of these modifications have shown some degree of improvement for gene transfer, the use of polyamides intravesically in conjunction with an adenoviral system shows the most promise and the greatest potential to supplement or even replace the current treatment modalities for superficial bladder cancer.

Gene therapy of human bladder cancer with adenovirus-mediated antisense basic fibroblast growth factor.

We previously investigated the role of basic fibroblast growth factor (bFGF) as a mediator of angiogenesis, tumorigenicity, and metastasis of transitional cell carcinoma (TCC) of the bladder. In the present study, we determined whether adenoviral-mediated antisense bFGF gene transfer therapy (Ad bFGF-AS) would inhibit TCCs growing in the subcutis of nude mice. In vitro, Ad bFGF-AS inhibited endothelial cell proliferation and enhanced apoptosis. The highly metastatic human TCC cell line 253J-BV(R) was implanted ectopically in the subcutis of athymic nude mice, and therapy was begun when the tumors reached a diameter between 5 and 7 mm. Intralesional therapy with Ad bFGF-AS decreased the in vivo expression of bFGF and matrix metalloproteinase type 9 mRNA and protein, and reduced microvessel density and enhanced endothelial cell apoptosis. Tumor growth was significantly inhibited by Ad bFGF-AS (mean, 58 mg) compared with controls [saline (mean, 562 mg), beta-galactosidase adenovirus (mean, 586 mg), and sense bFGF adenoviral therapy (Ad bFGF-S; mean, 3012 mg)]. These results suggest that Ad bFGF-AS therapy affects endothelial cells directly and tumor cells indirectly through down-regulation of bFGF and matrix metalloproteinase type 9, resulting in endothelial cell apoptosis and significant tumor growth inhibition. Furthermore, these studies confirm that bFGF expression is a valid target for the therapy of bladder cancer.

Treatment of human metastatic transitional cell carcinoma of the bladder in a murine model with the anti-vascular endothelial growth factor receptor monoclonal antibody DC101 and paclitaxel.

Vascular endothelial cell growth factor (VEGF) regulates angiogenesis and metastasis of bladder cancer (transitional cell carcinoma, TCC) through binding to VEGF receptor-2 (VEGFR-2). In this study, we evaluated whether the anti-VEGFR monoclonal antibody (Mab) DC101 in combination with paclitaxel inhibited tumorigenesis, angiogenesis, and metastasis of human TCC growing within the bladder of athymic nude mice. In vivo therapy with Mab DC101 and paclitaxel induced significant regression of bladder tumors compared with either agent alone. Median bladder weights were reduced from 601 mg in untreated controls, 422 mg in mice treated with paclitaxel alone (P < 0.005), 361 mg in mice treated with DC101 alone (P < 0.005), and 113 mg in mice that received combination therapy (P < 0.0005). Only one of nine mice developed spontaneous lymph node metastasis after combined treatment, compared with seven of seven untreated controls (P < 0.0005), six of eight after DC101 (P < 0.01), and five of eight mice after paclitaxel (P < 0.05). Combined treatment with both paclitaxel and DC101 inhibited tumor-induced neovascularity compared with all other groups (P < 0.005), without altering the expression of VEGF or flk1. Mab DC101 and paclitaxel combined enhanced apoptosis in the tumor and endothelial cells compared with other treatment (P < 0.005). These studies indicate that Mab DC101, which blocks VEGFR-2 function, has significant efficacy against human TCC, especially when combined with the chemotherapeutic agent paclitaxel. The antitumor effect was mediated by inhibition of angiogenesis and induction of both tumor cell and endothelial cell apoptosis.

Biosafety of in vivo adenovirus-p53 intravesical administration in mice.

OBJECTIVES: To evaluate the biosafety and in vivo biodistribution of intravesical instillation of an adenovirus that contains human p53 gene. Mutations of p53, which are found in as many as 40% of transitional cell carcinomas, are associated with a poor prognosis and resistance to chemotherapy and radiation therapy. Restoration of wild-type p53 status by means of adenoviral-mediated therapy may enhance apoptosis and improve the response to therapy, but the issues of biosafety and toxicity have not yet been addressed. METHODS: Adenovirus-p53 (1 x 10(8), 1 x 10(9), and 5 x 10(9) pfu/mL) and luciferase reporter gene (5 x 10(9)) were instilled into the bladders of anesthetized female BALB/c mice. The mice were killed on days 1, 3, 6, and 13, and representative samples of the bladder, ureter, kidney, adrenal gland, ovary, liver, heart, and lung were removed for histologic evaluation. RESULTS: No histologic signs of toxicity were found. The hematologic and biochemical profiles of the mice were normal, with the exception of a transient elevation in liver function tests on day 1 in the three treatment groups. CONCLUSIONS: Intravesical instillation of adenovirus-p53 was well tolerated; the bladder urothelium appeared to prevent systemic dissemination. The results of these experiments support the safety of intravesical gene transfer by intravesical instillation.