Gordon A. Brown

The impact of variant histology on the outcome of bladder cancer treated with curative intent

Patient risk stratification is essential for optimal management of patients with bladder cancer. Risk status determines the application and timing of therapeutic interventions such as repeat transurethral resection, intravesical chemo- and immunotherapy, systemic chemotherapy, and radical cystectomy. One key factor in such risk stratification appears to be the presence of variant histologic patterns in the bladder tumor. More than 90% of tumors are conventional urothelial carcinoma, and the rest consist of urothelial carcinoma with aberrant differentiation (squamous/glandular differentiation, small cell carcinoma, sarcomatoid carcinoma, and micropapillary carcinoma) or nonurothelial carcinoma (squamous cell carcinoma and adenocarcinoma). In this review, we focus on the implications of aberrant differentiation on the management of patients with bladder cancer. All of the variant histologies portend a worse prognosis than pure urothelial carcinoma. Although radical cystectomy remains the mainstay of treatment in all forms of bladder cancer, we highlight the use of neoadjuvant chemotherapy in patients with subtypes responsive to such therapy.

Lymph Node Density Is Superior to TNM Nodal Status in Predicting Disease-Specific Survival After Radical Cystectomy for Bladder Cancer: Analysis of Pooled Data From MDACC and MSKCC

PURPOSE To compare the utility of lymph node density (LND) with TNM nodal status in predicting disease-specific survival (DSS) after radical cystectomy. PATIENTS AND METHODS We identified 248 patients with nodal metastasis after radical cystectomy (without neoadjuvant chemotherapy): 162 patients from Memorial Sloan-Kettering Cancer Center (MSKCC) and 86 patients from M.D. Anderson Cancer Center (MDACC). We assessed the effect of several variables on DSS. RESULTS After a median follow-up duration of 24 months, 134 patients died of their disease. The median DSS was 36 months, and the 1-year, 2-year, and 5-year DSS rates were 83.7%, 57.4%, and 36.6%, respectively. The median LND was 20%. The 5-year DSS rate was 54.6% for patients with LND < or = 20% v 15.3% for patients with LND higher than 20% (P < .01). Pathologic nodal (pN) status in patients was 78 for pN1 (32%), 127 for pN2 (51%), and 43 for pN3 (17%). On univariate analysis, pN status and LND were significant predictors of DSS (P < .01). However, when pN status and LND were considered jointly in a multivariate model, only LND higher than 20% predicted decreased DSS (hazard ratio [HR], 2.75; P < .01). In addition, while nonorgan-confined (ie, > pT2) primary tumor (HR, 2.40; P < .01) and adjuvant chemotherapy (HR, 0.47; P < .01) were predictors of DSS, LND remained a predictor of DSS even after accounting for adjuvant chemotherapy. CONCLUSION LND is superior to TNM nodal status in predicting DSS for patients with lymph node-positive disease after radical cystectomy, even in the context of adjuvant chemotherapy.

Nephroureterectomy for treating upper urinary tract transitional cell carcinoma: time to change the treatment paradigm?

To evaluate factors associated with disease recurrence and survival in patients undergoing nephroureterectomy for upper urinary tract transitional cell carcinoma (UUT‐TCC) in one centre over an 18‐year period.

Sensitivity to Epidermal Growth Factor Receptor Inhibitor Requires E-Cadherin Expression in Urothelial Carcinoma Cells

Purpose: Epidermal growth factor receptor (EGFR) is an attractive target for the treatment of urothelial carcinoma, but a clinical response can be expected in only a small proportion of patients. The aim of this study was to define molecular markers of response to cetuximab therapy in a panel of urothelial carcinoma cell lines. Experimental Design: Eleven cell lines were investigated for antiproliferative response to cetuximab based on [3H]thymidine incorporation. A variety of markers, including EGFR expression, phosphorylation, and gene amplification, as well as the expression of other growth factor receptors, their ligands, and markers of epithelial-to-mesenchymal transition were investigated. Cohens κ statistic was used to estimate the agreement between response and expression of these markers. E-cadherin was silenced by small interfering RNA in two sensitive cell lines, and the effect on the response to cetuximab was measured. Results: We were able to identify a panel of relevant markers pertaining especially to alternate growth factor receptor expression and epithelial-to-mesenchymal transition that predicted response to cetuximab. The data suggested that expression of intact HER-4 (κ, 1.00; P = 0.008), E-cadherin (κ, 0.81; P = 0.015), and β-catenin (κ, 0.81; P = 0.015) and loss of expression of platelet-derived growth factor receptor β (κ, 0.57; P = 0.167) were associated with response to cetuximab therapy. Silencing E-cadherin in two sensitive cell lines reduced responsiveness to cetuximab in both (P < 0.001). Conclusions: A panel of predictive markers for cetuximab response has been established in vitro and is currently being evaluated in a prospective clinical trial of neoadjuvant EGFR-targeted therapy. Most importantly, E-cadherin seems to play a central role in modulation of EGFR response in urothelial carcinoma.

Uncoupling between Epidermal Growth Factor Receptor and Downstream Signals Defines Resistance to the Antiproliferative Effect of Gefitinib in Bladder Cancer Cells

Activation of the epidermal growth factor receptor (EGFR) and downstream signaling pathways, such as phosphatidylinositol-3 kinase/Akt and Ras/mitogen-activated protein kinase (MAPK), have been implicated in causing resistance to EGFR-targeted therapy in solid tumors, including the urogenital tumors. To investigate the mechanism of resistance to EGFR inhibition in bladder cancer, we compared EGFR tyrosine kinase inhibitor (Gefitinib, Iressa, ZD1839) with respect to its inhibitory effects on three kinases situated downstream of EGFR: MAPK, Akt, and glycogen synthase kinase-3beta (GSK-3beta). We found that the resistance to the antiproliferative effects of gefitinib, in vitro as well as in vivo in nude mice models, was associated with uncoupling between EGFR and MAPK inhibition, and that GSK-3beta activation and degradation of its target cyclin D1 were indicators of a high cell sensitivity to gefitinib. Further analysis of one phenotypic sensitive (253J B-V) and resistant (UM-UC13) cell lines revealed that platelet-derived growth factor receptor-beta (PDGFRbeta) activation was responsible for short circuiting the EGFR/MAPK pathway for mitogenic stimuli. However, invasion as well as actin dynamics were efficiently reduced by EGFR inhibition in UM-UC13. Chemical disruption of signaling pathways or of PDGFR kinase activity significantly reduced the inactive pool of cellular GSK-3beta in UM-UC13 cells. In conclusion, our data show that the uncoupling of EGFR with mitogenic pathways can cause resistance to EGFR inhibition in bladder cancer. Although this uncoupling may arise through different mechanisms, we suggest that the resistance of bladder cancer cells to EGFR blockade can be predicted early in the course of treatment by measuring the activation of GSK-3beta and of nuclear cyclin D1.

Molecular correlates of gefitinib responsiveness in human bladder cancer cells

We characterized the effects of the small molecule epidermal growth factor receptor (EGFR) inhibitor gefitinib (ZD1839, Iressa) on cell proliferation in a panel of 17 human bladder cancer cell lines. Gefitinib inhibited DNA synthesis in a concentration-dependent fashion in 6 of 17 lines. Growth inhibition was associated with p27Kip1 accumulation and decreased cyclin-dependent kinase 2 activity. Gefitinib also inhibited baseline EGFR, AKT, and extracellular signal-regulated kinase (ERK) phosphorylation in the EGFR-dependent cells maintained in serum-free medium, whereas it had no effect on baseline EGFR or ERK phosphorylation in the EGFR-independent cells. Analyses of candidate markers of EGFR dependency revealed that the gefitinib-sensitive cells expressed higher surface EGFR levels than the gefitinib-resistant lines. Gefitinib-sensitive cells generally expressed higher levels of E-cadherin and lower levels of vimentin than the gefitinib-resistant cells, but these correlations were not perfect, suggesting that these markers of epithelial-mesenchymal transition cannot be used by themselves to prospectively predict EGFR-dependent growth. Together, our results show that bladder cancer cells are markedly heterogeneous with respect to their sensitivity to EGFR antagonists. Although surface EGFR levels and epithelial-mesenchymal transition status seem to roughly correlate with responsiveness, they cannot be used by themselves to identify bladder tumors that will be sensitive to EGFR-directed therapy. However, comparing levels of p27Kip1 or DNA synthesis before and after gefitinib exposure does identify the drug-sensitive cells. [Mol Cancer Ther 2007;6(1):277–85]

Molecular Markers of Urothelial Cancer and Their Use in the Monitoring of Superficial Urothelial Cancer

Multiple molecular markers have been described for use in bladder cancer patients. Some of these have been studied more extensively than others, and it is difficult for the clinician to maintain a perspective over the myriad findings that have been made. We have reviewed a selection of markers used for surveillance with an emphasis on clinical utility. The best studied markers and those with the most promising preliminary results were selected. Only studies that included surveillance for recurrence in patients with a history of bladder cancer were considered. Each marker is briefly described and its performance in monitoring bladder cancer patients is summarized. Several promising markers are available, although only four have obtained US Food and Drug Administration approval. The clinical applications that have been studied include replacement or reduction in the number of cystoscopies performed in the surveillance of bladder cancer patients, substitution for or complementary use with urinary cytology in the same setting, predicting disease recurrence and progression, and predicting and monitoring treatment response. None of the markers have been proved sensitive and specific enough to replace cystoscopy. Others, such as nuclear matrix protein 22 (NMP22) and UroVysion, appear to have some utility when used to complement or replace cytology. The other applications have not been adequately studied for any given marker. While multiple molecular markers exist for bladder cancer, their full clinical utility will not be realized until more multicenter prospective trials are conducted to verify their efficacy and safety in the monitoring of patients with superficial bladder cancer.

ADAM10 as a therapeutic target for cancer and inflammation.

Both cancer and chronic inflammatory diseases are often marked by homeostatic signal transduction pathways run amok. Cleavage of membrane-bound substrates by extracellular metalloproteinases is frequently the rate limiting step in activating many of these pathways, resulting either in liberation of active ligands (shedding) or initiating further processing into bioactive cytoplasmic domains (regulated intramembrane proteolysis or RIP). ADAM10 is a member of the ADAM (A Disintegrin And Metalloproteinase) family of transmembrane metalloproteinases implicated in the RIPing and shedding of dozens of substrates that drive cancer progression and inflammatory disease, including Notch, E-cadherin, EGF, ErbB2 and inflammatory cytokines. ADAM10s emerging role as a significant contributor to these pathologies has led to intense interest in it as a potential drug target for disease treatment. Here we discuss some of the established functions of ADAM10 and the implications of its inhibition in disease progression.

Comparing Lymphadenectomy During Radical Nephroureterectomy: Open Versus Laparoscopic

OBJECTIVES Laparoscopic nephroureterectomy (LNU) is an accepted treatment for tumors of the ureter and renal pelvis, although the ability to perform a regional lymphadenectomy has been criticized. We compared the quality of lymphadenectomy with LNU with that involving open nephroureterectomy (ONU) to determine whether oncologic principles are maintained. METHODS We searched our institutional database for patients who had undergone ONU from 1990 to 2005. These were compared with a series of patients from January 2003 to April 2007 who underwent LNU. From each patients medical records, we assessed the number of lymph nodes removed, the number of positive nodes removed, and the density of positive nodes. The differences between groups were analyzed using the Wilcoxon rank sum statistical test. RESULTS We identified 106 patients who underwent ONU with lymphadenectomy and 28 who underwent LNU with lymphadenectomy. The median number of nodes removed, median number of positive nodes, and median density of positive nodes were, respectively, 3, 0, and 0 for the ONU group; and 6, 0, and 0, for the LNU group. There was a statistically significant difference between groups with respect to the number of nodes removed (P = 0.01) but not with respect to the number of positive nodes removed (P = 0.61) or the lymph node density (P = 0.42). CONCLUSIONS Offsetting the benefits of laparoscopy could be a flawed oncologic technique. We have demonstrated that lymphadenectomy, which is a potentially important component of nephroureterectomy, can be performed as well during LNU as it is with ONU when a dedicated effort is made.

Validating bladder cancer xenograft bioluminescence with magnetic resonance imaging: the significance of hypoxia and necrosis

To assess the correlation in orthotopic bladder xenografts of bioluminescence imaging (BLI) with tumour volume as determined by magnetic resonance imaging (MRI), and to define the potential role of hypoxia and necrosis in the relationship between BLI and tumour volume at autopsy.