Temporal trends of bladder cancer incidence and mortality from 1990 to 2016 and projections to 2030

Global burden of bladder cancer attributable to smoking in 204 countries and territories, 1990-2019

Bladder cancer (BCa) poses a significant medical burden worldwide. However, the epidemiological pattern of the global smoking-induced BCa burden is unclear. Our analysis of the 2019 Global Burden of Disease (GBD) database showed a significant increase in the number of BCa cases worldwide from 1990 to 2019, with a clear upward trend in both age-standardized prevalence and incidence. In contrast, age-standardized rates of mortality (ASMR) and disability-adjusted life-years (ASDR) showed a downward trend, despite an increase in the absolute number of death and disability-adjusted life years. The burden of BCa caused by smoking is greater in males, middle-aged and older adults, and people in countries with high-middle socio-demographic indices (SDI). The study highlights the continuing global health challenge posed by smoking-related BCa. Targeted health policies and interventions are critical, especially in areas with high smoking rates and low socioeconomic status.

LncRNA MEG3 Inhibits the Epithelial-mesenchymal Transition of Bladder Cancer Cells through the Snail/E-cadherin Axis

OBJECTIVE

This study aimed to investigate the role of the long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) in the epithelial-mesenchymal transition (EMT) of bladder cancer cells and the potential mechanisms.

METHODS

Cell invasion, migration, and wound healing assays were conducted to assess the effects of MEG3 on the invasive and migratory capabilities of bladder cancer cells. The expression levels of E-cadherin were measured using Western blotting, RT-qPCR, and dual luciferase reporter assays. RNA immunoprecipitation and pull-down assays were performed to investigate the interactions between MEG3 and its downstream targets.

RESULTS

MEG3 suppressed the invasion and migration of bladder cancer cells and modulated the transcription of E-cadherin. The binding of MEG3 to the zinc finger region of the transcription factor Snail prevented its ability to transcriptionally repress E-cadherin. Additionally, MEG3 suppressed the phosphorylation of extracellular regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and P38, thereby decreasing the expression of Snail and stimulating the expression of E-cadherin.

CONCLUSION

MEG3 plays a vital role in suppressing the EMT in bladder cancer cells, indicating its potential as a promising therapeutic target for the treatment of bladder cancer.

Sex Does Not Affect Survival: A Propensity Score-Matched Comparison in a Homogenous Contemporary Radical Cystectomy Cohort

OBJECTIVES

To determine whether biological sex affects oncological outcome after extended pelvic lymph node dissection, radical cystectomy, and urinary diversion for muscle-invasive bladder cancer, and to identify risk factors impacting outcome.

PATIENTS AND METHODS

We performed a single-center, retrospective observational cohort study with prospective data collection with a propensity score matched population. A total of 1165 consecutive patients from 2000 to 2020, (317 women and 848 men) scheduled for open extended pelvic lymph node dissection, radical cystectomy, and urinary diversion for urothelial bladder cancer were included in the final analysis. Overall Survival (OS), Cancer-Specific-Survival (CSS), and Recurrence-Free-survival (RFS) were assessed with multivariable weighted Cox regression analysis as well as with propensity score matched Cox-Regression.

RESULTS

No significant difference was found between sexes regarding OS (HR 1.18, [0.93-1.49], P = .16), CSS (HR 0.87, [0.64-1.18], P = .38), or RFS (HR 0.80, [0.59-1.07], P = .13). These results were confirmed after propensity score matching: female sex was not associated with inferior OS (HR 1.20, [0.91-1.60], P = .19), CSS (HR 1.01, [0.75-1.35], P = .97) or RFS (HR 0.98, [0.75-1.27], P = .86).

CONCLUSIONS

We did not find a significant difference in cancer-related outcomes or overall survival after extended pelvic lymph node dissection, open radical cystectomy, and urinary diversion for urothelial cancer between males and females even after adjustment with propensity matching score for multiple factors including oncological parameters, smoking status, and renal function.

Comparison of Three Prediction Models for Predicting Chronic Obstructive Pulmonary Disease in China

Purpose

To predict the future number of patients with chronic obstructive pulmonary disease (COPD) in China and compare the three prediction models.

Methods

A generalized additive model (GAM), autoregressive integrated moving average (ARIMA) model, and curve-fitting method were used to fit and predict the number of patients with COPD in China. Data on the number of patients with COPD in China from 1990 to 2019 were obtained from the Global Burden of Disease (GBD) database. The coefficient of determination (R2), mean absolute error (MAE), mean absolute percentage error (MAPE), root mean squared error (RMSE), relative error of prediction, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) were used to evaluate and compare the fitting effect, prediction effect, and reliability of the three models.

Results

The GAM, ARIMA, and curve-fitting methods could predict future trends in COPD in China. The performance of the GAM is the best among the three models, whereas the curve fitting method is the worst, and the ARIMA (0,1,2) model is in between. The prediction results of the three models showed that the number of patients with COPD in China is expected to increase from 2020 to 2025.

Conclusion

GAM and AIRMA models are recommended for predicting the future prevalence of COPD in China. The number of patients with COPD in China is expected to increase in the next few years. The prevention and control of COPD in China still needs to be strengthened. Using appropriate models to predict future trends in COPD will provide support for health policymakers.

The global landscape of bladder cancer incidence and mortality in 2020 and projections to 2040

Background

Bladder cancer (BCa) is one of the most common urological malignancies worldwide. This study examines the global epidemiological profile of BCa incidence and mortality in 2020 and the projected burden to 2040.

Methods

The estimated number of BCa cases and deaths were extracted from the GLOBOCAN 2020 database. Age-standardised incidence rates (ASIRs) and age-standardised mortality rates (ASMRs) were calculated using the world standard. The predicted BCa incidence and mortality in 2040 was calculated based on demographic projections.

Results

Globally, approximately 573 000 new BCa cases and 213 000 deaths occurred in 2020, corresponding to ASIRs and ASMRs of 5.6 and 1.9 per 100 000, respectively. The incidence and mortality rates were approximately 4-fold higher in men (9.5 and 3.3 per 100 000, respectively) than women (2.4 and 0.9, respectively). Across world regions, incidence rates varied at least 12-fold among men and 8-fold among women, with the highest ASIRs for both men and women detected in Southern Europe (26.5 and 5.8 per 100 000, respectively) and Western Europe (21.5 and 5.8, respectively) and the lowest in Middle Africa (2.2) in men and South-Central Asia (0.7) in women. The highest ASMRs for both men and women were found in Northern Africa (9.2 and 1.8 per 100 000, respectively). By 2040, the annual number of new BCa cases and deaths will increase to 991 000 (72.8% increase from 2020) and 397 000 (86.6% increase), respectively.

Conclusions

Geographical distributions of BCa incidence and mortality uncovered higher risk of BCa incidence in Southern and Western European populations and higher risk of mortality in Northern African populations. Considering the predicted 73% and 87% increase in annual BCa cases and deaths by 2040 globally, respectively, there is an urgent need to develop and accelerate BCa control initiatives for high-risk populations to tackle global BCa burden and narrow its geographical disparities.

Construction of Pyroptosis-Related Prognostic and Immune Infiltration Signature in Bladder Cancer

Pyroptosis is a kind of programmed cell death related to inflammation, which is closely related to cancer. The goal of this study is to establish and verify pyroptosis-related gene signature to predict the prognosis of patients with bladder cancer (BLCA) and explore its relationship with immunity. Somatic mutation, copy number variation, correlation, and expression of 33 pyroptosis-related genes were evaluated based on The Cancer Genome Atlas (TCGA) database. BLCA cases were divided into two clusters by consistent clustering and found that pyroptosis-related genes were related to the overall survival (OS) of BLCA. The least absolute shrinkage and selection operator (LASSO) Cox regression was used to construct the signature (including 7 pyroptosis-realated genes). Survival analysis curve and receiver operating characteristic curve (ROC) showed that this signature could predict the prognosis of BLCA patients. Univariate and multivariate Cox regression analysis showed the independent prognostic value of this model. Immune infiltration analysis showed that the six types of immune cells have significantly different infiltrations. The effect of immunotherapy is better in the low-risk group. In summary, our effort indicated the potential role of pyroptosis-related genes in BLCA and provided new perspectives on the prognosis of BLCA and new ideas for immunotherapy.

Secular trends of morbidity and mortality of prostate, bladder, and kidney cancers in China, 1990 to 2019 and their predictions to 2030

Background

Prostate, bladder and kidney cancers are common age-related genitourinary cancers. China's population is aging at an increasing rate, so predicting the morbidity and mortality of prostate, bladder, and kidney cancer in China is of great significance to provide epidemiological evidence for forward planning and implementation of national health policies.

Methods

Numbers of incidences and deaths by cancer (prostate, bladder and kidney), sex (male and female) and age groups from 1990 to 2019 were extracted from the Global Burden of Disease (GBD) Study. We applied Bayesian age-period-cohort models to predict incidences and deaths to 2030. We also calculated Age-standardized incidence rate (ASIR) and mortality rate (ASMR), their trends were quantified by estimated average percentage change (EAPC) and 95% confidence interval (CI).

Results

Predictions suggest that by 2030, there will be 315,310 prostate cancer cases, 192,390 bladder cancer cases and 126,980 kidney cancer cases. The ASIRs will increase to 25.54/100,000 for prostate cancer (EAPC: 2.88, 95% CI, 2.84, 2.93), 7.54/100,000 for bladder cancer (EAPC: 2.58, 95% CI, 2.54, 2.61) and 5.63/100,000 for kidney cancer (EAPC: 4.78, 95% CI, 4.54, 5.02). Number of deaths in 2030 will be 81,540, 61,220, and 41,940, respectively. Different ASMR changes are observed, the ASMR for prostate cancer will drop to 7.69/100,000 (EAPC: -0.29, 95% CI, -0.31, -0.27), the ASMR for bladder cancer will stabilize at 2.49/100,000 (EAPC: 0.00, 95% CI, -0.02, 0.03), the ASMR of kidney cancer will increase to 1.84/100,000 (EAPC: 3.45, 95% CI, 3.22, 3.67). From 1990 to 2030, higher numbers of cases and rates are reported among males and in the 60 plus age group, both ASIR and ASMR of bladder and kidney cancers presents progressively widening differences between both males and females and between the < 60 and the ≥ 60 age groups.

Conclusion

Morbidity and mortality of the three genitourinary cancers are predicted to increase further over the next decade. It highlights the need for timely development and implementation of optimal health policies to curb the epidemic trends.

A Multiomics Profiling Based on Online Database Revealed Prognostic Biomarkers of BLCA

Background

Bladder cancer (BLCA) is one of the most common urological malignancies globally, posing a severe threat to public health. In combination with protein-protein interaction (PPI) network analysis of proteomics, Gene Set Variation Analysis (GSVA) and “CancerSubtypes” package of R software for transcriptomics can help identify biomarkers related to BLCA prognosis. This will have significant implications for prevention and treatment.

Method

BLCA data were downloaded from The Cancer Genome Atlas (TCGA) database and GEO database (GSE13507). GSVA analysis converted the gene expression matrix to the gene set expression matrix. “CancerSubtypes” classified patients into three subtypes and established a prognostic model based on differentially expressed gene sets (DEGSs) among the three subtypes. For genes from prognosis-related DEGSs, functional and pathway enrichment analyses and PPI network analysis were carried out. The Human Protein Atlas (HPA) database was used for validation. Finally, the proportion of tumor-infiltrating immune cells (TIICs) was determined using the CIBERSORT algorithm.

Results

In total, 414 tumor samples and 19 adjacent-tumor samples were obtained from TCGA, with 145 samples belonging to subtype A, 126 samples belonging to subtype B, and 136 samples belonging to subtype C. Then, we identified 83 DEGSs and constituted a prognostic signature with two of them: “GSE1460_CD4_THYMOCYTE_VS_THYMIC_STROMAL_CELL_DN” and “MODULE_253.” Finally, five subnets of two PPI networks were established, and nine core proteins were obtained: CDH2, COL1A1, EIF2S2, PSMA3, NAA10, DNM1L, TUBA4A, KIF11, and KIF23. The HPA database confirmed the expression of the nine core proteins in BLCA tissues. Furthermore, EIF2S2, PSMA3, DNM1L, and TUBA4A could be novel BLCA prognostic biomarkers.

Conclusions

In this study, we discovered two gene sets linked to BLCA prognosis. PPI analysis confirmed the network's core proteins, and several newly discovered biomarkers of BLCA prognosis were identified.

Development and Validation of Ferroptosis-Related LncRNA Biomarker in Bladder Carcinoma

Bladder cancer (BC) is a highly prevalent cancer form of the genitourinary system; however, the effective biomarkers are still ambiguous and deserve deeper investigation. Long non-coding RNA (lncRNA) occupies a prominent position in tumor biology and immunology, and ferroptosis-related genes participate in regulatory processes of cancer. In this study, 538 differentially expressed ferroptosis-related lncRNAs were identified from the The Cancer Genome Atlas database through co-expression method and differential expression analysis. Then, the samples involved were equally and randomly divided into two cohorts for the construction of gene model and accuracy verification. Subsequently, a prediction model containing five ferroptosis-related lncRNAs was constructed by LASSO and Cox regression analysis. Furthermore, in terms of predictive performance, consistent results were achieved in the training set, testing set, and entire set. Kaplan–Meier curve, receiver operating characteristic area under the curve, and principal component analysis results verified the good predictive ability of model, and the gene model was confirmed as an independent prognostic indicator. To further investigate the mechanism, we explored the upstream of five lncRNAs and found that they may be modified by m6A to increase or decrease their expression in BC. Importantly, the low-risk group displayed higher mutation burden of tumors and lower Tumor Immune Dysfunction and Exclusion score, which may be predicted to have a higher response rate to immunotherapy. Interestingly, the patients in the high-risk group appeared to have a higher sensitivity to traditional chemotherapeutic agents through pRRophetic analysis. In general, our research established a five-ferroptosis-related lncRNA signature, which can be served as a promising prognostic biomarker for BC.

Survival in bladder and upper urinary tract cancers in Finland and Sweden through 50 years

Survival has improved in bladder cancer but few studies have considered extended periods or covered populations for which medical care is essentially free of charge. We analyzed survival in urothelial cancer (UC, of which vast majority are bladder cancers) in Finland and Sweden over a 50-year period (1967–2016) using data from the NORDCAN database. Finland and Sweden are neighboring countries with largely similar health care systems but higher economic resources and health care expenditure in Sweden. We present results on 1- and 5-year relative survival rates, and additionally provide a novel measure, the difference between 1- and 5-year relative survival, indicating how well survival was maintained between these two periods. Over the 50-year period the median diagnostic age has increased by several years and the incidence in the very old patients has increased vastly. Relative 1- year survival rates increased until early 1990s in both countries, and with minor gains later reaching about 90% in men and 85% in women. Although 5-year survival also developed favorably until early 1990s, subsequent gains were small. Over time, age specific differences in male 1-year survival narrowed but remained wide in 5-year survival. For women, age differences were larger than for men. The limitations of the study were lack of information on treatment and stage. In conclusion, challenges are to improve 5-year survival, to reduce the gender gap and to target specific care to the most common patient group, those of 70 years at diagnosis. The most effective methods to achieve survival gains are to target control of tobacco use, emphasis on early diagnosis with prompt action at hematuria, upfront curative treatment and awareness of high relapse requiring regular cystoscopy follow up.

Genetic variants in splicing factor genes and susceptibility to bladder cancer

BACKGROUND

Genome-wide association studies have demonstrated that genetic variants are closely related to tumorigenesis and progression of cancer. However, the correlation between genetic variants in splicing factor genes and bladder cancer susceptibility remains unclear.

METHOD

A case-control study with 580 cases of bladder cancer and 1,101 controls was conducted to explore the association of single-nucleotide polymorphisms (SNPs) in splicing factors with bladder cancer susceptibility by logistic regression models, and multiple testing errors were justified by the false discovery rate (FDR) method. Next, we used the Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) datasets to further analyze the differential expression of candidate genes.

RESULTS

We found that rs978416 G>A in RBFOX3 contributed to a reduced risk of bladder cancer [adjusted odds ratio (OR) = 0.72, 95% confidence internal (CI) = 0.62-0.84, P = 3.54 × 10^-5], especially in individuals who never smoked (P = 7.83 × 10^-5). Stratified analysis showed that the protective effect of rs978416 was more significant in the subgroup of low grade and non-muscle invasive bladder cancer. Furthermore, the RBFOX3 mRNA expression was decreased in bladder tumor tissues. However, the relatively high expression of RBFOX3 was related to a higher bladder cancer stage.

CONCLUSIONS

Our findings indicated that SNP rs978416 G>A in RBFOX3 may be related to bladder cancer predisposition in Chinese population and might serve as a novel biomarker for bladder cancer risk.

Systemic immune-inflammation index is a promising non-invasive biomarker for predicting the survival of urinary system cancers: a systematic review and meta-analysis

OBJECTIVE

Systemic immune-inflammation index (SII) has been reported in numerous studies to effectively predict the survival outcomes of urinary system cancers; however no agreement has been reached. This meta-analysis aimed to explore the prognostic significance of pre-treatment SII in tumours of the urinary system.

METHODS

Relevant published articles were selected from Web of Science, PubMed, Embase, and the Cochrane Library up to 30 August 2020. The hazard ratios (HRs) with 95% confidence intervals (CIs) were computed to estimate the associations of pre-treatment SII with overall survival (OS), progression-free survival (PFS), cancer-specific survival (CSS) in urinary system cancers.

RESULTS

13 papers were included in our meta-analysis. From the combined data, we found that a high pre-treatment SII indicated a markedly worse OS (HR = 1.98; 95% CI: 1.75-2.23; p < .001), PFS (HR: 2.08; 95% CI: 1.32-3.26; p = .002), and CSS (HR: 2.41, 95% CI: 1.73-3.35, p < .001). Additionally, patients with an elevated SII value might have undesirable pathological characteristics, including a large tumour size, a poor differentiation grade, and an advanced tumour stage (all p < .001).

CONCLUSIONS

Pre-treatment SII could be used as a non-invasive and promising biomarker to indicate the prognosis of urinary system cancer patients.KEY MESSAGES:This meta-analysis evaluates the predictive value of systemic immune-inflammation index (SII) for patients with urinary system cancer.A high pre-treatment SII indicates a poor prognosis.SII can serve as a promising non-invasive biomarker to help clinicians assess the prognosis and develop treatment strategies for urinary system cancer patients.

Grape Seed Proanthocyanidins Inhibit Migration and Invasion of Bladder Cancer Cells by Reversing EMT through Suppression of TGF-β Signaling Pathway

Bladder cancer (BC) is the most common cancer of the urinary system. Despite advances in diagnosis and therapy, the prognosis is still poor because of recurrence and metastasis. Epithelial-mesenchymal transition (EMT) is considered to play an important role in the invasion and metastasis of BC. Grape seed proanthocyanidins (GSPs) exhibit chemopreventive and chemotherapeutic activities against several types of cancer. However, their effects and underlying mechanisms on the invasive potential of BC remain unclear. In this study, we found that GSPs inhibited migration, invasion, and MMP-2/-9 secretion of both T24 and 5637 bladder cancer cells at noncytotoxic concentrations. We also discovered that 5637 cells were more suitable than T24 cells for the EMT study. Further study showed that GSPs inhibited EMT by reversing the TGF-β-induced morphological change and upregulation of mesenchymal markers N-cadherin, vimentin, and Slug as well as downregulation of epithelial markers E-cadherin and ZO-1 in 5637 cells. GSPs also inhibited TGF-β-induced phosphorylation of Smad2/3, Akt, Erk, and p38 in 5637 cells without affecting the expression of total Smad2/3, Akt, Erk, and p38. Taken together, the results of the present study demonstrate that GSPs effectively inhibit the migration and invasion of BC cells by reversing EMT through suppression of the TGF-β signaling pathway, which indicates that GSPs could be developed as a potential chemopreventive and therapeutic agent against bladder cancer.

Integrative analysis of immune molecular subtypes and microenvironment characteristics of bladder cancer

The emergence of immunotherapy has provided an option of treatment methods for bladder cancer (BC). However, the beneficiaries of immunotherapy are still limited to small‐scale patients, and immunotherapy‐related adverse events often occur. It is a major challenge for clinical work to study the immune subtypes of BC and the molecular mechanism of immune escape, and identify the immune responders accurately. Here, we explore the immune molecular subtypes of bladder cancer and potential escape mechanisms. First, we screened the expression profiles of 303 differentially expressed immune‐related genes in BC patients from the Cancer Genome Atlas (TCGA) database, and successfully identified 4 molecular subtypes of BC. By comparing the clinical characteristics, immune cells infiltration, the expression of checkpoint genes, human leukocyte antigen (HLA) genes, and gene mutation status of different subtypes, we identified different clinical and immunological characteristics of 4 subtypes. Among 4 subtypes, Cluster 2 met the general characteristics of immunotherapy responders and responded well to immunotherapy, while Cluster 4 had the highest expression of immune characteristics, and is similar to the immune environment of normal bladder tissue. Then, the weighted gene co‐expression network analysis (WGCNA) of immune‐related genes revealed that brown module was positively correlated with subtypes. Pathway enrichment analysis explored the major pathways associated with subtypes, which are also associated with immune escape mechanisms. Moreover, the decision tree model, which was constructed by the principle of random forest screening factors, was also validated in internal validation set and external validation set from the Gene Expression Omnibus (GEO) cohort (GSE133624), and could achieve accurate subtypes prediction for BC patients with high‐throughput sequencing. Taken together, we explored the immune molecular subtypes and their mechanisms of BC, and these results may provide guidance for the development of new BC immunotherapy strategies.

Bladder and upper urinary tract cancers as first and second primary cancers

Background

Previous population‐based studies on second primary cancers (SPCs) in urothelial cancers have focused on known risk factors in bladder cancer patients without data on other urothelial sites of the renal pelvis or ureter.

Aims

To estimate sex‐specific risks for any SPCs after urothelial cancers, and in reverse order, for urothelial cancers as SPCs after any cancer. Such two‐way analysis may help interpret the results.

Methods

We employed standardized incidence ratios (SIRs) to estimate bidirectional relative risks of subsequent cancer associated with urothelial cancers. Patient data were obtained from the Swedish Cancer Registry from years 1990 through 2015.

Results

We identified 46 234 urinary bladder cancers (75% male), 940 ureteral cancers (60% male), and 2410 renal pelvic cancers (57% male). After male bladder cancer, SIRs significantly increased for 9 SPCs, most for ureteral (SIR 41.9) and renal pelvic (17.2) cancers. In the reversed order (bladder cancer as SPC), 10 individual FPCs were associated with an increased risk; highest associations were noted after renal pelvic (21.0) and ureteral (20.9) cancers. After female bladder cancer, SIRs of four SPCs were significantly increased, most for ureteral (87.8) and pelvic (35.7) cancers. Female bladder, ureteral, and pelvic cancers associated are with endometrial cancer.

Conclusions

The risks of recurrent urothelial cancers were very high, and, at most sites, female risks were twice over the male risks. Risks persisted often to follow‐up periods of >5 years, motivating an extended patient follow‐up. Lynch syndrome‐related cancers were associated with particularly female urothelial cancers, calling for clinical vigilance.

Can Smoking Cause Differences in Urine Microbiome in Male Patients With Bladder Cancer? A Retrospective Study

Background

Tobacco smoking is a carcinogen for many cancers including bladder cancer. The microbiota is involved in the occurrence, development, and treatment of tumors. We explored the composition of male urinary microbiome and the correlation between tobacco smoking and microbiome in this study.

Methods

Alpha diversity, principal component analysis (PCA) and Adonis analysis, linear discriminant analysis (LDA) coupled with effect size measurement, and PICRUSt function predictive analysis were used to compare different microbiome between smokers and non-smokers in men.

Results

There were 26 qualified samples included in the study. Eleven of them are healthy controls, and the others are from men with bladder cancer. Simpson index and the result of PCA analysis between smokers and non-smokers were not different (P > 0.05) in healthy men. However, the abundance of Bacteroidaceae, Erysipelotrichales, Lachnospiraceae, Bacteroides, and so on in the urinary tract of smokers is much higher than that of non-smokers. Compared to non-smokers, the alpha diversity in smokers was elevated in patients with bladder cancer (P < 0.05). PCA analysis showed a significant difference between smokers and non-smokers (P < 0.001), indicating that tobacco smoking plays a vital role in urinary tract microbial composition.

Conclusion

The composition of microbiome in the urinary tract is closely related to tobacco smoking. This phenomenon is more significant in patients with bladder cancer. This indicates tobacco smoking may promote the occurrence and development of bladder cancer by changing urinary tract microbiome.

Incidence trends in bladder and lung cancers between Denmark, Finland and Sweden may implicate oral tobacco (snuff/snus) as a possible risk factor

Background

The dominant risk factor for urinary bladder cancer has been cigarette smoking, but, as smoking prevalence is decreasing in many populations, other risk factors may become uncovered. Such new risk factors could be responsible for halting the declining incidence of bladder cancer. We hypothesize that snuff use by Swedish men may increase the rate for bladder cancer, as snuff contains carcinogenic nitrosamines.

Methods

We carried out an ecological study by comparing incidence trends in lung and bladder cancers between Danish, Finnish and Swedish men in order to test if the Swedish bladder cancer rate deviates from the Danish and Finnish ones. We used the NORDCAN database for cancer data from 1960 through 2016 to test the hypothesis.

Results

In the three countries, the incidence of lung cancer started to decrease after a peak incidence, and this was later followed by declining incidence in bladder cancer in Denmark from 1990 to 2016 by 14.3%, in Finland by 8.3% but not in Sweden (the decline of 1.4% was not significant). The difference in trends can be partly explained by the increasing incidence in Swedish men aged 70 or more years. Sweden differs from the two other countries by low male smoking prevalence but increasing use of snuff recorded by various surveys.

Conclusion

The stable bladder cancer trend for Swedish men was opposite to the declining trends in Denmark, Finland and globally. We suggest that this unusual finding may be related to the increasing use of snuff by Swedish men. Average users of snuff are exposed to at least 3 times higher levels of carcinogenic tobacco-specific nitrosamines than a smoker of one daily pack of cigarettes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08371-w.

Screening and identification of hub genes in bladder cancer by bioinformatics analysis and KIF11 is a potential prognostic biomarker

Bladder cancer (BC) is the ninth most common lethal malignancy worldwide. Great efforts have been devoted to clarify the pathogenesis of BC, but the underlying molecular mechanisms remain unclear. To screen for the genes associated with the progression and carcinogenesis of BC, three datasets were obtained from the Gene Expression Omnibus. A total of 37 tumor and 16 non-cancerous samples were analyzed to identify differentially expressed genes (DEGs). Subsequently, 141 genes were identified, including 55 upregulated and 86 downregulated genes. The protein-protein interaction network was established using the Search Tool for Retrieval of Interacting Genes database. Hub gene identification and module analysis were performed using Cytoscape software. Hierarchical clustering of hub genes was conducted using the University of California, Santa Cruz Cancer Genomics Browser. Among the hub genes, kinesin family member 11 (KIF11) was identified as one of the most significant prognostic biomarkers among all the candidates. The Kaplan Meier Plotter database was used for survival analysis of KIF11. The expression profile of KIF11 was analyzed using the ONCOMINE database. The expression levels of KIF11 in BC samples and bladder cells were measured using reverse transcription-quantitative pCR, immunohistochemistry and western blotting. In summary, KIF11 was significantly upregulated in BC and might act as a potential prognostic biomarker. The present identification of DEGs and hub genes in BC may provide novel insight for investigating the molecular mechanisms of BC.