One particular challenge in the treatment of kidney tumors is the range of histologies and tumor phenotypes a renal mass can represent. A kidney tumor can range from benign (e.g., oncocytoma) to a clinically indolent malignancy (e.g., papillary type I, chromophobe) to aggressive disease [e.g., papillary type II or high-grade clear cell renal cell carcinoma (ccRCC)]. Even among various subtypes, kidney cancers are genetically diverse with variable prognoses and treatment response rates. Therefore, the key to proper treatment is the differentiation of these subtypes. Currently, a wide array of diagnostic, prognostic, and predictive biomarkers exist that may help guide the individualized care of kidney cancer patients. This review will discuss the various serum, urine, imaging, and immunohistological biomarkers available in practice.

Purpose: Ureteral stent-related pain is a well-known side effect of stent placement. To date, there is a paucity of resources that address this topic. Herein, we present theories on stent pain pathophysiology, summarize available pain outcomes data for different stent designs, and provide an overview of the management of stent pain, including pre-placement modifiers, medical management, and other considerations. Materials and Methods: This narrative review focused primarily on articles indexed in the PubMed®, Google Scholar™, and EMBASE databases. No formal search strategy was used and no meta-analysis of data was performed. Results: Stent pain pathophysiology is multifactorial and likely a result of mucosal irritation along with retrograde reflux of urine. While there is a consensus on the lack of association between stent length, diameter and stent-related flank pain, stents should be properly sized so as to prevent dislodgement. Insufficient data exists comparing stent materials and durometry. Multiple drug-eluting stents are in development and have demonstrated promising early results. Alpha-blockers have shown efficacious results and should be considered along with or in combination with anticholinergics and NSAIDs in the treatment of ureteral-stent related symptoms, with judicious consideration of their side effect profiles. Periureteral botulinum toxin A injections are a promising novel treatment modality. Conclusions: Ureteral stent pain is common and multiple modalities have been studied and are in clinical use for its treatment. Care should be taken to avoid placement of stents if possible, with continual reassessment of indications to maintain stents in patients. Relative heterogeneity among studies and small sample sizes makes creating specific evidence-based pain management recommendations challenging. Alpha-blockers, anti-muscarinics and NSAIDs are all generally well tolerated and effectively reduce symptoms, but patient-specific factors must be the paramount consideration when choosing monotherapy or combination therapy. Future studies are needed to better define ideal material characteristics and pharmacologic treatments.

The role of androgen receptor in renal cell carcinoma is not well understood. In this study the correlation between androgen receptor mRNA expression and clinicopathological features in patients with localized renal cell carcinoma was investigated. Additionally, human renal cell carcinoma cell lines were examined for the presence and effect of androgen receptor. Androgen receptor mRNA expression was evaluated by quantitative real-time polymerase chain reaction in 115 tumor samples from patients with primary pathological stage T1 or T2 (pT1/pT2) renal cell carcinoma and 57 specimens of corresponding normal kidney tissue. Reverse transcriptase-polymerase chain reaction and Western blot were done to examine the expression of androgen receptor in human renal cell carcinoma cell lines. Effects on cellular proliferation were investigated after activating and blocking androgen signaling in tissue culture. Androgen receptor mRNA expression levels were significantly higher in patients with pT2 tumors than in those with pT1 tumors (p = 0.011). Kaplan-Meier estimates revealed significant differences in time to progression and cancer specific survival between low and high androgen receptor mRNA expression groups regardless of gender. Multivariate Cox regression analysis demonstrated that the level of androgen receptor expression was an independent predictor of cancer specific survival (HR 15.546, 95% CI 1.320-183.131, p = 0.029). In tissue culture treatment with dihydrotestosterone caused proliferation in androgen receptor positive cell lines while enzalutamide resulted in reduced cell viability in a dose dependent manner. In patients with localized renal cell carcinoma the androgen receptor mRNA expression level is associated with prognosis. In addition, cell culture data suggest that enzalutamide may have an effect in limiting the growth of androgen receptor positive renal cell carcinoma.