Padraic O'Malley

Muscle Invasive Bladder Cancer (MIBC) is a subset of bladder cancer with a significant risk for metastases and death. It accounts for nearly 25% of bladder cancer diagnoses. A diagnostic work-up for MIBC is inclusive of urologic evaluation, radiographic imaging with a CT scan, urinalysis, and cystoscopy. These evaluations, especially cystoscopy, are invasive and carry the risk of secondary health concerns. Non-invasive diagnostics such as urine cytology are an attractive alternative currently being investigated to mitigate the requirement for cystoscopy. A pitfall in urine cytology is the lack of available options with high reliability, specificity, and sensitivity to malignant bladder cells. Exosomes are a novel biomarker source which could resolve some of the concerns with urine cytology, due to the high specificity as the surrogates of tumor cells. This review serves to define muscle invasive bladder cancer, current urine cytology methods, the role of exosomes in MIBC, and exosomes application as a diagnostic tool in MIBC. Urinary exosomes as the specific populations of extracellular vesicles could provide additional biomarkers with specificity and sensitivity to bladder malignancies, which are a consistent source of cellular information to direct clinicians for developing treatment strategies. Given its strong presence and differentiation ability between normal and cancerous cells, exosome-based urine cytology is highly promising in providing a perspective of a patient’s bladder cancer.

Expression of the transmembrane protein PD-L1 is frequently upregulated in cancer. Because PD-L1–expressing cells can induce apoptosis or anergy of T lymphocytes through binding to the PD1 receptor, the PD-L1–mediated inhibition of activated PD1⁺ T cells is considered a major pathway for tumor immune escape. However, the mechanisms that regulate the expression of PD-L1 in the tumor microenvironment are not fully understood. Analysis of organotypic tumor tissue slice cultures, obtained from mice with implanted syngeneic tumors (MBT2 bladder tumors in C3H mice, Renca kidney, and CT26 colon tumors in BALB/c mice), as well as from patients with cancer, revealed that tumor-associated hyaluronan (HA) supports the development of immunosuppressive PD-L1⁺ macrophages. Using genetically modified tumor cells, we identified epithelial tumor cells and cancer-associated mesenchymal fibroblast-like cells as a major source of HA in the tumor microenvironment. These HA-producing tumor cells, and particularly the vimentin-positive fibroblast-like cells of bone marrow origin, directly interact with tumor-recruited myeloid cells to form large stromal congregates/clusters that are highly enriched for both HA and PD-L1. Furthermore, similar cell clusters composed of HA-producing fibroblast-like cells and PD-L1⁺ macrophages were detected in tumor-draining, but not in distant, lymph nodes. Collectively, our findings indicate that the formation of multiple large HA-enriched stromal clusters that support the development of PD-L1–expressing APCs in the tumor microenvironment and draining lymph nodes could contribute to the immune escape and resistance to immunotherapy in cancer. Key Points Hyaluronan-enriched tumor stroma supports the development of PD-L1⁺ cell clusters. Fibroblasts and epithelial tumor cells serve as the main source of hyaluronan. Hyal2-expressing myeloid cells contribute to the development of PD-L1⁺ macrophages.

Introduction: To evaluate the effect of urine pH on tumor recurrence rates in patients undergoing surveillance after initial diagnosis of non-muscle invasive bladder cancer (NMIBC). Materials and methods: All patients diagnosed with NMIBC at a tertiary referral center from January 2004 to March 2015 were reviewed. Our primary outcome was time to first recurrence after transurethral resection of bladder tumor (TURBT). Patients were analyzed according to the average urine pH of all urinalysis data over the surveillance period from TURBT to first recurrence. Kaplan-Meier survival analysis was used to determine differences in median time to recurrence. Cox proportional hazards regression was used to assess independent predictors of cancer recurrence. Results: A total of 252 patients were included, of which 155 patients had average pH <= 6 (median pH 5.5) and 97 patients had average pH > 6 (median pH 6.8), p < 0.001. There was no significant difference in median time to recurrence between low/acidic pH (<= 6) and high/basic pH (> 6) groups (28 months versus 17 months, respectively, p = 0.3444). Similarly, urine pH did not affect the risk of recurrence in a subgroup analysis stratified by smoking status. On multivariable Cox regression analysis, there was no association between average pH and recurrence among high grade tumors (HR = 1.33, 95% CI = 0.76 to 2.34, p = 0.3186), or low grade tumors (HR = 1.013, 95% CI = 1.01 to 1.58, p = 0.96). Conclusions: There was no association between urine pH and risk of tumor recurrence, regardless of smoking status. These findings suggest that modification of urine pH is unlikely to decrease the frequency of tumor recurrence in patients with NMIBC.

Background: Vasectomy has been implicated as a risk factor for prostate cancer in multiple epidemiologic studies over the past 25 years. Whether this relationship is causal remains unclear. This study examines the association between vasectomy and prostate cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, which randomized men to usual care or annual prostate cancer screening. Methods: We performed a retrospective analysis of 13-year screening and outcomes data from the PLCO trial. Multivariable Cox proportional hazards regression stratified by study arm and age at vasectomy was performed. Results: There was an increased risk of prostate cancer in men who had undergone a vasectomy and were randomized to the usual care arm of the study (adjusted HR, 1.11; 95% confidence interval, 1.03–1.20; P = 0.008). There was no association between vasectomy and diagnosis of prostate cancer in men randomized to the prostate cancer screening arm. Only men undergoing vasectomy at an older age in the usual care arm of the study, but not the prostate cancer screening arm, were at increased risk of being diagnosed with prostate cancer. Conclusions: Vasectomy was not associated with prostate cancer risk among men who were screened for prostate cancer as part of a clinical trial, but was associated with prostate cancer detection in men receiving usual care. Impact: The positive association between vasectomy and prostate cancer is likely related to increased detection of prostate cancer based on patterns of care rather than a biological effect of vasectomy on prostate cancer development. Cancer Epidemiol Biomarkers Prev; 26(11); 1653–9. ©2017 AACR.