Genome-wide Meta-analysis Identifies Novel Genes Associated with Recurrence and Progression in Non-muscle-invasive Bladder Cancer

Fast and accurate recurrent event analysis for genome-wide association studies

Many diseases recur after recovery, for example, recurrences in cancer and infections. However, research is often focused on analysing only time-to-first recurrence, thereby ignoring any subsequent recurrences that may occur after the first. Statistical models for the analysis of recurrent events are available, of which the extended Cox proportional hazards frailty model is the current state-of-the-art. However, this model is too statistically complex for computationally efficient application in high-dimensional data sets, including genome-wide association studies (GWAS). Here, we develop an application for fast and accurate recurrent event analysis in GWAS, called SPARE (SaddlePoint Approximation for Recurrent Event analysis). In SPARE, every DNA variant is tested for association with recurrence risk using a modified score statistic. A saddlepoint approximation is implemented to achieve statistical accuracy. SPARE controls the Type I error, and its statistical power is similar to existing recurrent event models, yet SPARE is significantly faster. An application of SPARE in a recurrent event GWAS on bladder cancer for 6.2 million DNA variants in 1,443 individuals required less than 15 min, whereas existing recurrent event methods would require several weeks.

Central Composite Design for Optimization of Mitomycin C-Loaded Quantum Dots/Chitosan Nanoparticles as Drug Nanocarrier Vectors

Cancer is one of the most devastating diseases that leads to a high degree of mortality worldwide. Hence, extensive efforts have been devoted to the development of drug nanocarrier vectors as a potential new cancer treatment option. The main goal of this treatment is to deliver an anticancer medicine successfully and effectively to the patient's cells using non-toxic nanocarriers. Here, we present a drug delivery system to emphasize the optimization of an anticancer drug-loaded formulation using Mitomycin C (MMC) encapsulated in chitosan nanocarrier conjugated with a bioimaging fluorescence probe of Mn:ZnS quantum dots (MMC@CS-Mn:ZnS). Additionally, the Response Surface Methodology (RSM), which uses a quadratic model to forecast the behaviour of the nano-drug delivery system, was used to assess the optimization of encapsulation efficiency. In this investigation, the core points of the Central Composite Design (CCD) model were used with 20 runs and 6 replications. The encapsulation efficiency (EE%) was measured using UV-Vis spectroscopy at 362 nm. The highest EE% is 55.31 ± 3.09 under the optimum parameters of incubation time (105 min), concentration of MMC (0.875 mg/mL), and concentration of nanocarriers (5.0 mg/mL). Physicochemical characterizations for the nanocarriers were accessed using a nanosizer and field-emission scanning electron microscopy (FESEM). Three independent variables for the evaluation of the encapsulation efficiency were used, in which the incubation time, concentration of MMC, concentration of nanocarriers, and correlation for each variable were studied. Furthermore, the MMC drug release efficiency was carried out in four different solution pHs of 5.5, 6.0, 6.5, 7.0, and pH 7.5, and the highest cumulative drug release of 81.44% was obtained in a pH 5.5 release medium, followed by cumulative releases of 68.55%, 50.91%, 41.57%, and 32.45% in release mediums with pH 6.0, pH 6.5, pH 7.0, and pH 7.5. Subsequently, five distinct mathematical models-pseudo-first-order, pseudo-second-order, Hixson-Crowell, Korsmeyer-Peppas, and Higuchi kinetic models-were used to fit all of the drug release data. The Korsmeyers-Peppas model was found to fit it well, highlighting its importance for the log of cumulative drug release proportional to the log of time at the equilibrium state. The correlation coefficient value (R²) was obtained as 0.9527, 0.9735, 0.9670, 0.9754, and 0.9639 for the drug release in pH 5.5, pH 6.0, pH 6.5, pH 7.0, and pH 7.5, respectively. Overall, from the analysis, the as-synthesized MMC nanocarrier (MMC@CS-Mn:ZnS) synergistically elucidates the underlying efficient delivery of MMC and leverages the drug loading efficiency, and all these factors have the potential for the simultaneous curbing of non-muscle invasive bladder cancer reoccurrence and progression when applied to the real-time disease treatment.

Epidemiology, Screening, and Prevention of Bladder Cancer

CONTEXT

Bladder cancer (BC) represents a significant health problem due to the potential morbidity and mortality associated with disease burden, which has remained largely unaltered over time.

OBJECTIVE

To provide an expert collaborative review and describe the incidence, prevalence, and mortality of BC and to evaluate current evidence for BC screening and prevention.

EVIDENCE ACQUISITION

Data on the estimated incidence and mortality of BC for 2020 in 185 countries were derived from the International Agency for Research on Cancer GLOBOCAN database. A review of English-language articles published over the past 5 yr was conducted using PubMed/MEDLINE to identify risk factors in addition to contemporary evidence on BC screening and prevention.

EVIDENCE SYNTHESIS

BC is the tenth most common cancer worldwide, with 573 278 cases in 2020. BC incidence is approximately fourfold higher in men than women. Tobacco smoking remains the principal risk factor, accounting for approximately 50% of cases. There is insufficient evidence to recommend routine BC screening. However, targeted screening of high-risk individuals (defined according to smoking history or occupational exposure) may reduce BC mortality and should be the focus of prospective randomized trials. In terms of disease prevention, smoking cessation represents the most important intervention, followed by a reduction in exposure to occupational and environmental carcinogens.

CONCLUSIONS

BC confers a significant disease burden. An understanding of BC epidemiology and risk factors provides an optimal foundation for disease prevention and the care of affected patients.

PATIENT SUMMARY

Bladder cancer is the tenth most common cancer worldwide and is approximately four times more common among men than among women. The main risk factors are tobacco smoking, followed by exposure to carcinogens in the workplace or the environment. Routine screening is not currently recommended, but may be beneficial in individuals at high risk, such as heavy smokers. Primary prevention is extremely important, and smoking cessation represents the most important action for reducing bladder cancer cases and deaths.

Predicting Recurrence of Non-Muscle-Invasive Bladder Cancer: Current Techniques and Future Trends

Bladder cancer (BC) is the 10th most common cancer globally and has a high mortality rate if not detected early and treated promptly. Non-muscle-invasive BC (NMIBC) is a subclassification of BC associated with high rates of recurrence and progression. Current tools for predicting recurrence and progression on NMIBC use scoring systems based on clinical and histopathological markers. These exclude other potentially useful biomarkers which could provide a more accurate personalized risk assessment. Future trends are likely to use artificial intelligence (AI) to enhance the prediction of recurrence in patients with NMIBC and decrease the use of standard clinical protocols such as cystoscopy and cytology. Here, we provide a comprehensive survey of the most recent studies from the last decade (N = 70 studies), focused on the prediction of patient outcomes in NMIBC, particularly recurrence, using biomarkers such as radiomics, histopathology, clinical, and genomics. The value of individual and combined biomarkers is discussed in detail with the goal of identifying future trends that will lead to the personalized management of NMIBC.

Identification of Genetic Risk Factors for Familial Urinary Bladder Cancer: An Exome Sequencing Study

PURPOSE

Previous studies have shown an approximately two-fold elevation in the relative risk of urinary bladder cancer (UBC) among people with a family history that could not be entirely explained by shared environmental exposures, thus suggesting a genetic component in its predisposition. Multiple genome-wide association studies and recent gene panel sequencing studies identified several genetic loci that are associated with UBC risk; however, the list of UBC-associated variants and genes is incomplete.

MATERIALS AND METHODS

We exome sequenced eight patients from three multiplex UBC pedigrees and a group of 77 unrelated familial UBC cases matched to 241 cancer-free controls. In addition, we examined pathogenic germline variation in 444 candidate genes in 392 The Cancer Genome Atlas UBC cases.

RESULTS

In the pedigrees, segregating variants were family-specific although the identified genes clustered in common pathways, most notably DNA repair (MLH1 and MSH2) and cellular metabolism (IDH1 and ME1). In the familial UBC group, the proportion of pathogenic and likely pathogenic variants was significantly higher in cases compared with controls (P = .003). Pathogenic and likely pathogenic variant load was also significantly increased in genes involved in cilia biogenesis (P = .001). In addition, a pathogenic variant in CHEK2 (NM_007194.4:c.1100del; p.T367Mfs*15) was over-represented in cases (variant frequency = 2.6%; 95% CI, 0.71 to 6.52) compared with controls (variant frequency = 0.21%; 95% CI, 0.01 to 1.15), but was not statistically significant.

CONCLUSION

These results point to a complex polygenic predisposition to UBC. Despite heterogeneity, the genes cluster in several biologically relevant pathways and processes, for example, DNA repair, cilia biogenesis, and cellular metabolism. Larger studies are required to determine the importance of CHEK2 in UBC etiology.