Absence of Tumor on Repeat Transurethral Resection of Bladder Tumor Does Not Predict Final Pathologic T0 Stage in Bladder Cancer Treated with Radical Cystectomy.

BACKGROUND: For patients with bladder cancer (BC) receiving neoadjuvant chemotherapy (NAC), complete pathologic absence of tumor (pT0) at radical cystectomy (RC) is associated with better survival. It is unclear if pT0 status can be attributed to the absence of residual disease (cT0) on transurethral resection of bladder tumor (TURBT) or to the effects of NAC. OBJECTIVE: To determine how often cT0 is associated with pT0 and identify preoperative and postoperative factors associated with survival. DESIGN, SETTING, AND PARTICIPANTS: Between 1995 and 2011, 157 out of 1897 RC patients were identified as stage cT0 after at least two TURBT procedures at a single center. INTERVENTION: RC with or without NAC. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Initial TURBT pathology and clinical staging were reviewed. The primary endpoint was pathologic stage at RC. Cox proportional hazards ratios identified factors associated with residual disease at RC, overall survival (OS), recurrence-free survival (RFS), and disease-specific survival (DSS). RESULTS AND LIMITATIONS: Of the cT0 patients, 49.7% (n=78) underwent NAC. pT0 was found in 35.7% (n=56). Residual tumor was found at RC in 63.7% (n=101), of whom 24.8% (n=39) had advanced disease (≥pT3 or node-positive disease). Positive lymph nodes at RC were found in 12.7% (n=20) of the patients. There was no significant difference in achieving pT0 status between patients with and without NAC. The presence of advanced BC was most predictive of OS. NAC was associated with longer OS and RFS. During median follow-up of 6.3 yr, the 5-yr RFS was 81% for those with non-advanced disease and 46% for advanced BC (p<0.001). The 5-yr OS rate was 77% for non-advanced BC and 46% for invasive BC (p<0.001). Limitations include the retrospective design. CONCLUSIONS: Complete TURBT does not predict pT0 at RC. A notable fraction of patients with cT0 bladders have locally advanced and/or lymph node-positive disease. These findings may be of value when counseling patients on bladder preservation strategies for muscle-invasive BC. PATIENT SUMMARY: Among patients thought to have had the entire tumor in their bladder removed via cystoscopy, a majority have persistent tumors when their bladders were removed. In a sizable proportion, these persistent tumors were even more invasive than initially thought.

Positive association of collagen type I with non-muscle invasive bladder cancer progression.

PURPOSE: Non-muscle invasive bladder cancers (NMIBC) are generally curable, while ~15% progresses into muscle-invasive cancer with poor prognosis. While efforts have been made to identify genetic alternations associated with progression, the extracellular matrix (ECM) microenvironment remains largely unexplored. Type I collagen is a major component of the bladder ECM, and can be altered during cancer progression. We set out to explore the association of type I collagen with NMIBC progression. EXPERIMENTAL DESIGN: The associations of COL1A1 and COL1A2 mRNA levels with progression were evaluated in a multi-center cohort of 189 patients with NMIBCs. Type I collagen protein expression and structure were evaluated in an independent single-center cohort of 80 patients with NMIBCs. Immunohistochemical analysis was performed and state-of-the-art multi-photon microscopy was used to evaluate collagen structure via second harmonic generation imaging. Progression to muscle invasion was the primary outcome. Kaplan-Meier method, Cox regression, and Wilcoxon rank-sum were used for statistical analysis. RESULTS: There is a significant association of high COL1A1 and COL1A2 mRNA expression in patients with poor progression-free survival (P=0.0037 and P=0.011, respectively) and overall survival (P=0.024 and P=0.012, respectively). Additionally, immunohistochemistry analysis of type I collagen protein deposition revealed a significant association with progression (P=0.0145); Second-harmonic generation imaging revealed a significant lower collagen fiber curvature ratio in patients with invasive progression (P = 0.0018). CONCLUSIONS: Alterations in the ECM microenvironment, particularly type I collagen, likely contributes to bladder cancer progression. These findings will open avenues to future functional studies to investigate ECM-tumor interaction as a potential therapeutic intervention to treat NMIBCs.

Blocking PGE2-induced tumour repopulation abrogates bladder cancer chemoresistance.

Cytotoxic chemotherapy is effective in debulking tumour masses initially; however, in some patients tumours become progressively unresponsive after multiple treatment cycles. Previous studies have demonstrated that cancer stem cells (CSCs) are selectively enriched after chemotherapy through enhanced survival. Here we reveal a new mechanism by which bladder CSCs actively contribute to therapeutic resistance via an unexpected proliferative response to repopulate residual tumours between chemotherapy cycles, using human bladder cancer xenografts. Further analyses demonstrate the recruitment of a quiescent label-retaining pool of CSCs into cell division in response to chemotherapy-induced damages, similar to mobilization of normal stem cells during wound repair. While chemotherapy effectively induces apoptosis, associated prostaglandin E2 (PGE2) release paradoxically promotes neighbouring CSC repopulation. This repopulation can be abrogated by a PGE2-neutralizing antibody and celecoxib drug-mediated blockade of PGE2 signalling. In vivo administration of the cyclooxygenase-2 (COX2) inhibitor celecoxib effectively abolishes a PGE2- and COX2-mediated wound response gene signature, and attenuates progressive manifestation of chemoresistance in xenograft tumours, including primary xenografts derived from a patient who was resistant to chemotherapy. Collectively, these findings uncover a new underlying mechanism that models the progressive development of clinical chemoresistance, and implicate an adjunctive therapy to enhance chemotherapeutic response of bladder urothelial carcinomas by abrogating early tumour repopulation.

Normal and neoplastic urothelial stem cells: getting to the root of the problem.

Most epithelial tissues contain self-renewing stem cells that mature into downstream progenies with increasingly limited differentiation potential. It is not surprising that cancers arising from such hierarchically organized epithelial tissues retain features of cellular differentiation. Accumulating evidence suggests that the urothelium of the urinary bladder is a hierarchically organized tissue, containing tissue-specific stem cells that are important for both normal homeostasis and injury response. The phenotypic and functional properties of cancer stem cells (CSCs; also known as tumour-initiating cells) from bladder cancer tissue have been studied in detail. Urothelial CSCs are not isolated by a 'one-marker-fits-all' approach; instead, various cell surface marker combinations (possibly reflecting the cell-of-origin) are used to isolate CSCs from distinct differentiation subtypes of urothelial carcinomas. Additional CSC markers, including cytokeratin 14 (CK14), aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), and tumour protein 63 (p63), have revealed prognostic value for urothelial carcinomas. Signalling pathways involved in normal stem cell self-renewal and differentiation are implicated in the malignant transformation of different subsets of urothelial carcinomas. Early expansion of primitive CK14+ cells--driven by genetic pathways such as STAT3--can lead to the development of carcinoma in situ, and CSC-enriched urothelial carcinomas are associated with poor clinical outcomes. Given that bladder CSCs are the proposed root of malignancy and drivers of cancer initiation and progression for urothelial carcinomas, these cells are ideal targets for anticancer therapies.

Stat3 activation in urothelial stem cells leads to direct progression to invasive bladder cancer.

Two subtypes of human bladder cancer, noninvasive papillary and muscle-invasive cancer, develop through independent pathologic and molecular pathways. Human invasive bladder cancer frequently develops without prior clinical evidence of a noninvasive tumor stage. However, an animal model that recapitulates this unique clinical progression of invasive bladder cancer has not yet been developed. In this study, we created a novel transgenic mouse model of invasive bladder cancer by targeting an active dimerized form of Stat3 to the basal cells of bladder epithelium. When exposed to the carcinogen nitrosamine, Stat3-transgenic mice developed invasive cancer directly from carcinoma in situ (CIS), bypassing the noninvasive papillary tumor stage. Remarkably, invasive bladder cancer driven by active Stat3 was predominantly composed of stem cells, which were characterized by cytokeratin 14 (CK14) staining and enhanced tumor sphere-forming ability. Active Stat3 was also shown to localize to the nucleus of human invasive bladder cancers that were primarily composed of CK14+ stem cells. Together, our findings show that Stat3-induced stem cell expansion plays a critical role in the unique clinical progression of invasive bladder cancer through the CIS pathway.

Three differentiation states risk-stratify bladder cancer into distinct subtypes.

Current clinical judgment in bladder cancer (BC) relies primarily on pathological stage and grade. We investigated whether a molecular classification of tumor cell differentiation, based on a developmental biology approach, can provide additional prognostic information. Exploiting large preexisting gene-expression databases, we developed a biologically supervised computational model to predict markers that correspond with BC differentiation. To provide mechanistic insight, we assessed relative tumorigenicity and differentiation potential via xenotransplantation. We then correlated the prognostic utility of the identified markers to outcomes within gene expression and formalin-fixed paraffin-embedded (FFPE) tissue datasets. Our data indicate that BC can be subclassified into three subtypes, on the basis of their differentiation states: basal, intermediate, and differentiated, where only the most primitive tumor cell subpopulation within each subtype is capable of generating xenograft tumors and recapitulating downstream populations. We found that keratin 14 (KRT14) marks the most primitive differentiation state that precedes KRT5 and KRT20 expression. Furthermore, KRT14 expression is consistently associated with worse prognosis in both univariate and multivariate analyses. We identify here three distinct BC subtypes on the basis of their differentiation states, each harboring a unique tumor-initiating population.