Survival Analysis of 314 Episodes of Sepsis in Medical Intensive Care Unit in University Hospital: Impact of Intensive Care Unit Performance and Antimicrobial Therapy

Aim: To evaluate epidemiology of sepsis in medical intensive care unit (ICU) in University Hospital, and the impact of ICU performance and appropriate empirical antibiotic therapy on survival of septic patients. Methods: Observational, partly prospective study conducted over 6 years assessed all patients meeting the criteria for sepsis at ICU admission. Clinical presentation of sepsis was defined according to 2001 International Sepsis Definitions Conference. Demographic data, admission category, source of infection, severity of sepsis, ICU or hospital stay and outcome, ICU performance, and appropriateness of empirical antibiotic therapy were analyzed. Results: The analysis included 314 of 5022 (6.3%) patients admitted to ICU during the study period. There were 176 (56.1%) ICU survivors. At the ICU admission, sepsis was present in 100 (31.8%), severe sepsis in 89 (28.6%), and septic shock in 125 (39.8%) patients with mortality rates 17%, 33.7%, 72.1%, respectively. During ICU treatment, 244 (77.7%) patients developed at least one organ dysfunction syndrome. Of 138 (43.9%) patients who met the criteria for septic shock, 107 (75.4) were non-survivors (P<0.001). Factors associated with in-ICU mortality were acquisition of sepsis at another department (odds ratio [OR] 0.06; 95% confidence interval [CI], 0.02-0.19), winter season (OR 0.42; 0.20-0.89), limited mobility (OR 0.28; 0.14-0.59), ICU length of stay (OR 0.82; 0.75-0.91), sepsis-related organ failure assessment (SOFA) score on day 1 (OR 0.80; 0.72-0.89), history of global heart failure (OR 0.33; 0.16-0.67), chronic obstructive pulmonary disease-connected respiratory failure (OR 0.50; 0.27-0.93), septic shock present during ICU treatment (OR 0.03; 0.01-0.10), and negative blood culture at admission (OR 2.60; 0.81-6.23). Microbiological documentation of sepsis was obtained in 235 (74.8%) patients. Urinary tract infections were present in 168 (53.5%) patients, followed by skin or soft tissue infections in 58 (18.5%) and lower respiratory tract infections in 44 (14.0%) patients. Lower respiratory tract as focus of sepsis was connected with worse outcome (P<0.001). Empirical antibiotic treatment was considered adequate in 107 (60.8%) survivors and 42 (30.4%) non-survivors. Patients treated with adequate empirical antibiotic therapy had significantly higher survival time in hospital (log-rank, P=0.001). Conclusion: The mortality rate of sepsis was unacceptably high. The odds for poor outcome increased with acquisition of sepsis at another department, winter season, limited mobility, higher SOFA score on day 1, history of chronic global heart failure, COPD-connected respiratory failure, and septic shock present during ICU treatment, whereas longer ICU length of stay, positive blood culture, and adequate empirical antibiotic therapy were protective factors

THE ROLE OF INTERLEUKIN 6 IN THE DEVELOPMENT OF BLADDER CANCER

UVOD Uloga upale u procesu razvoja tumora mokraćnog mjehura slabo je istražena. Kronična upala izazvana infekcijom parazitom Shistosoma haematobium povezana je s nastankom tumora mokraćnog mjehura, a najuspješnija terapija tih tumora temelji se na upalnoj reakciji izazvanoj primjenom BCG-a. Pokazano je kako su jedni od najvažnijih promotora upale u tumorima citokin interleukin 6 (IL6) i transkripcijski faktor STAT3. Uz pomoć mišjeg modela u kojima su tumori mokraćnog mjehura izazvani karcinogenom BBN, istražili smo ulogu IL6 usporedivši tumore miša divljeg tipa (WT) s tumorima miševa koji ne sadrže gena za IL6 (IL6 KO). Istražili smo apsolutne i relativne promjene izražaja IL6 i STAT3 te drugih imunološki važnih gena u tumorskom tkivu mokraćnog mjehura miševa i ljudi. METODE Istraživanje apsolutnih promjena izražaja svih gena u modelu tumora izazvanog BBN-om provedeno je postupkom RNA sekvenciranja, a relativni izražaj IL6, STAT3 te imunološki važnih biljega istražen je lančanom reakcijom polimerazom u stvarnom vremenu (qPCR) u tumorima miševa i pacijenata. Upotrebom kemikalije BBN inducirani su tumori mokraćnog mjehura u WT i IL6 KO miševima. Tumori miševa i pacijenata su analizirani patohistološkim metodama te imunodetekcijom specifičnim protutijelima. REZULTATI U ovom istraživanju pokazali smo da do najznačajnijih promjena u izražaju gena tijekom indukcije tumora dolazi unutar skupine gena vezanih za imunološki odgovor. Bilježimo zakašnjeli upalni odgovor limfocitima T u akutnom modelu te značajan porast izražaja gena koji ukazuju na supresiju limfocita T tijekom razvoja tumora mokraćnog mjehura. Utvrdili smo da je izražaj IL6 povećan u tumorima kod miša, no da opada s napredovanjem tumora. Potpuno odstranjenje IL6 uzrokovalo je lošiji fenotip nastalih tumora, vjerojatno zbog pojačanog izražaja gena povezanih s utišavanjem imunološkog odgovora na tumore. U mjehurima netretiranih IL6 KO miševa smanjen je izražaj IL1α, a u tumorima tih miševa dolazi do značajnog porasta GM-CSF. U tumorima ljudi dolazi do smanjenja izražaja upalnog citokina IL6 te povećanja aktivnosti važnih upalnih transkripcijskih čimbenika STAT3 i NF-κB kao i TGFβ ciklina D1 i VEGF. ZAKLJUČAK Ovim istraživanjem pokazali smo da su tumori izazvani kemikalijom BBN odličan model za proučavanje imunoloških procesa pri nastanku i razvoju tumora mokraćnog mjehura. Utvrdili smo da je razina izražaja IL6 u tumorima povećana, ali da potpuno odstranjivanje IL6 iz organizma potiskuje imunološki odgovor u tumorima mokraćnog mjehura. Također, promatrajući izražaj gena utvrdili smo da IL6 regulira količinu GM-CSF u tumorima, te IL1α u zdravom tkivu mokraćnog mjehura. Unatoč smanjenom izražaju IL6 u tumorima pacijenata, izražaj STAT3, NF-κB, VEGFA, ciklina D1 i TGFβ je povećan.BACKGROUND The role of inflammation in urinary bladder cancer (BC) pathogenesis is poorly understood. Chronic inflammation caused by Schistosoma haematobium infestation can induce BC, while acute inflammation caused by BCG is used as a therapy for BC. It has been shown that one of the main molecular links between inflammation and cancer are cytokine IL6 and transcription factor STAT3. By using BBN-induced bladder cancer model in wild type (WT) and IL6 deficient mice (IL6 KO) we tested the effect of IL6 on BC development. Histopathological and immunohistochemical analysis as well as gene expression profiling (by RNA sequencing and RT2-PCR profiling) show important role of IL6 in BC development METHODS We performed the absolute and relative quantitation of differential gene expression in murine model of BBN-induced bladder cancer by means of RNA sequencing and real-time PCR. Pathohistological features of murine and patient tumors were examined and immunodetection was performed to analyze proliferative properties of tumors. Relative expression of inflammation-related genes in bladder cancer patients was determined using real-time PCR. RESULTS In this study, we demonstrate significant changes in inflammation-related gene expression during development of bladder cancer induced by BBN. IL6 was upregulated in murine bladder cancer model, but we also observe significant decrease in gene expression during tumor progression. We show that IL6 KO mice display aberrant T cellrelated gene expression in response to acute treatment with BBN. Furthermore, IL6 KO mice show immunosuppressive bladder cancer profile and a significant increase in GMCSF. IL6 expression was downregulated in human patient samples, but expression of STAT3, NF-κB, TGFβ, cyclin D1 and VEGFA was significantly upregulated. CONCLUSION This study provides evidence that BBN-induced bladder cancer is an optimal model for investigating inflammatory events during bladder cancer progression. We confirm that IL6 KO mice display impaired acute-phase response and we show that impaired IL6 signaling causes immunosuppression during bladder cancer. Our findings demonstrate that IL6 might be involved in regulation of GM-CSF and IL1α

THE ROLE OF INTERLEUKIN 6 IN THE DEVELOPMENT OF BLADDER CANCER

UVOD Uloga upale u procesu razvoja tumora mokraćnog mjehura slabo je istražena. Kronična upala izazvana infekcijom parazitom Shistosoma haematobium povezana je s nastankom tumora mokraćnog mjehura, a najuspješnija terapija tih tumora temelji se na upalnoj reakciji izazvanoj primjenom BCG-a. Pokazano je kako su jedni od najvažnijih promotora upale u tumorima citokin interleukin 6 (IL6) i transkripcijski faktor STAT3. Uz pomoć mišjeg modela u kojima su tumori mokraćnog mjehura izazvani karcinogenom BBN, istražili smo ulogu IL6 usporedivši tumore miša divljeg tipa (WT) s tumorima miševa koji ne sadrže gena za IL6 (IL6 KO). Istražili smo apsolutne i relativne promjene izražaja IL6 i STAT3 te drugih imunološki važnih gena u tumorskom tkivu mokraćnog mjehura miševa i ljudi. METODE Istraživanje apsolutnih promjena izražaja svih gena u modelu tumora izazvanog BBN-om provedeno je postupkom RNA sekvenciranja, a relativni izražaj IL6, STAT3 te imunološki važnih biljega istražen je lančanom reakcijom polimerazom u stvarnom vremenu (qPCR) u tumorima miševa i pacijenata. Upotrebom kemikalije BBN inducirani su tumori mokraćnog mjehura u WT i IL6 KO miševima. Tumori miševa i pacijenata su analizirani patohistološkim metodama te imunodetekcijom specifičnim protutijelima. REZULTATI U ovom istraživanju pokazali smo da do najznačajnijih promjena u izražaju gena tijekom indukcije tumora dolazi unutar skupine gena vezanih za imunološki odgovor. Bilježimo zakašnjeli upalni odgovor limfocitima T u akutnom modelu te značajan porast izražaja gena koji ukazuju na supresiju limfocita T tijekom razvoja tumora mokraćnog mjehura. Utvrdili smo da je izražaj IL6 povećan u tumorima kod miša, no da opada s napredovanjem tumora. Potpuno odstranjenje IL6 uzrokovalo je lošiji fenotip nastalih tumora, vjerojatno zbog pojačanog izražaja gena povezanih s utišavanjem imunološkog odgovora na tumore. U mjehurima netretiranih IL6 KO miševa smanjen je izražaj IL1α, a u tumorima tih miševa dolazi do značajnog porasta GM-CSF. U tumorima ljudi dolazi do smanjenja izražaja upalnog citokina IL6 te povećanja aktivnosti važnih upalnih transkripcijskih čimbenika STAT3 i NF-κB kao i TGFβ ciklina D1 i VEGF. ZAKLJUČAK Ovim istraživanjem pokazali smo da su tumori izazvani kemikalijom BBN odličan model za proučavanje imunoloških procesa pri nastanku i razvoju tumora mokraćnog mjehura. Utvrdili smo da je razina izražaja IL6 u tumorima povećana, ali da potpuno odstranjivanje IL6 iz organizma potiskuje imunološki odgovor u tumorima mokraćnog mjehura. Također, promatrajući izražaj gena utvrdili smo da IL6 regulira količinu GM-CSF u tumorima, te IL1α u zdravom tkivu mokraćnog mjehura. Unatoč smanjenom izražaju IL6 u tumorima pacijenata, izražaj STAT3, NF-κB, VEGFA, ciklina D1 i TGFβ je povećan.BACKGROUND The role of inflammation in urinary bladder cancer (BC) pathogenesis is poorly understood. Chronic inflammation caused by Schistosoma haematobium infestation can induce BC, while acute inflammation caused by BCG is used as a therapy for BC. It has been shown that one of the main molecular links between inflammation and cancer are cytokine IL6 and transcription factor STAT3. By using BBN-induced bladder cancer model in wild type (WT) and IL6 deficient mice (IL6 KO) we tested the effect of IL6 on BC development. Histopathological and immunohistochemical analysis as well as gene expression profiling (by RNA sequencing and RT2-PCR profiling) show important role of IL6 in BC development METHODS We performed the absolute and relative quantitation of differential gene expression in murine model of BBN-induced bladder cancer by means of RNA sequencing and real-time PCR. Pathohistological features of murine and patient tumors were examined and immunodetection was performed to analyze proliferative properties of tumors. Relative expression of inflammation-related genes in bladder cancer patients was determined using real-time PCR. RESULTS In this study, we demonstrate significant changes in inflammation-related gene expression during development of bladder cancer induced by BBN. IL6 was upregulated in murine bladder cancer model, but we also observe significant decrease in gene expression during tumor progression. We show that IL6 KO mice display aberrant T cellrelated gene expression in response to acute treatment with BBN. Furthermore, IL6 KO mice show immunosuppressive bladder cancer profile and a significant increase in GMCSF. IL6 expression was downregulated in human patient samples, but expression of STAT3, NF-κB, TGFβ, cyclin D1 and VEGFA was significantly upregulated. CONCLUSION This study provides evidence that BBN-induced bladder cancer is an optimal model for investigating inflammatory events during bladder cancer progression. We confirm that IL6 KO mice display impaired acute-phase response and we show that impaired IL6 signaling causes immunosuppression during bladder cancer. Our findings demonstrate that IL6 might be involved in regulation of GM-CSF and IL1α

The epidemiology and diagnostic approach to acute pulmonary embolism in the university hospital [Epidemiološki pokazatelji i dijagnostički pristup bolesniku s akutnom plućnom embolijom u kliničkoj bolnici]

The aim of this retrospective study was to evaluate the demographics and clinical characteristics of patients with pulmonary embolism treated in medical intensive care unit (ICU) at the University Hospital during a six-year period, and to assess the impact of several risk factors on patients' survival. The study included 165 patients, mean age 69.3 +/- 13.7 years, predominantly female (70.3%). Dominant symptom was dyspnea (97.0%), the most common sign tachypnea (69.6%). Pulmonary embolism was confirmed by high-probability ventilation/perfusion lung scan or multidetector computed tomography in 71.5% and was regarded as massive in 63 (38.2%), submassive in 23 (13.9%) and non massive in 79 patients (47.9%). Mean hospital stay was 5.7 +/- 4.4 days for ICU, and 14.8 +/- 9.1 days, overall. The ICU mortality was 26.7% and in-hospital mortality 30.9%. No statistical difference in mortality between male and female patients was observed (30.6% and 31.0%, respectively; p = 0.965), but prolonged immobilization (p = 0.002), recent operation (p = 0.034) or malignancy (p = 0.009) were shown to influence the outcome. Although a number of risk factors for developing pulmonary embolism have been identified and heparin prophylaxis along with early mobilization proposed to reduce the incidence, pulmonary embolism remains an important clinical problem with high mortality rate. The diagnostics should not wait and the therapy should start as soon as possible

Epidemiološki pokazatelji i dijagnostički pristup bolesniku s akutnom plućnom embolijom u kliničkoj bolnici

The aim of this retrospective study was to evaluate the demographics and clinical characteristics of patients with pulmonary embolism treated in medical intensive care unit (ICU) at the University Hospital during a six-year period, and to assess the impact of several risk factors on patients' survival. The study included 165 patients, mean age 69.3 +/- 13.7 years, predominantly female (70.3%). Dominant symptom was dyspnea (97.0%), the most common sign tachypnea (69.6%). Pulmonary embolism was confirmed by high-probability ventilation/perfusion lung scan or multidetector computed tomography in 71.5% and was regarded as massive in 63 (38.2%), submassive in 23 (13.9%) and non massive in 79 patients (47.9%). Mean hospital stay was 5.7 +/- 4.4 days for ICU, and 14.8 +/- 9.1 days, overall. The ICU mortality was 26.7% and in-hospital mortality 30.9%. No statistical difference in mortality between male and female patients was observed (30.6% and 31.0%, respectively; p = 0.965), but prolonged immobilization (p = 0.002), recent operation (p = 0.034) or malignancy (p = 0.009) were shown to influence the outcome. Although a number of risk factors for developing pulmonary embolism have been identified and heparin prophylaxis along with early mobilization proposed to reduce the incidence, pulmonary embolism remains an important clinical problem with high mortality rate. The diagnostics should not wait and the therapy should start as soon as possible.Cilj ove retrospektivne studije bio je procijeniti demografske i kliničke karakteristike bolesnika s plućnom embolijom liječenih u internističkoj jedinici intenzivnog liječenja (JIL) u Kliničkoj bolnici tijekom šestogodišnjeg perioda, s procjenom značaja pojedinih rizičnih čimbenika na njihovo preživljenje. U studiju je uključeno 165 bolesnika, prosječne dobi 69,3 ± 13,7 godina, 70,3% ispitivane populacije su činile žene. Kao najčešći simptom zabilježena je dispneja (97,0%), a kao najčešći klinički znak tahipneja (69,6%). Plućna je embolija dokazana ventilacijsko-perfuzijskom scintigrafijom pluća ili multidetektorskom kompjuteriziranom tomografijom u 71,5% bolesnika, stratificiranih u skupine s masivnom plućnom embolijom (63 bolesnika – 38,2%), submasivnom (23 bolesnika – 13,9%) i ne masivnom plućnom embolijom (79 bolesnika – 47,9%). Prosječno trajanje liječenja u JIL iznosilo je 5,7 ± 4,4 dana, a ukupno 14,8 ± 9,1 dana. Smrtnost u JIL iznosila je 26,7%, a cjelokupna bolnička smrtnost 30,9%. Nije na|eno statistički značajne razlike u smrtnosti bolesnika po spolu (30,6%:31,0%, p=0,965), dokazan je statistički značajan utjecaj dugotrajne imobilizacije (p=0,002), nedavnog operativnog zahvata (p=0,034) i maligne bolesti (p=0,009) na ishod liječenja. Iako su definirani različiti rizični čimbenici za nastanak plućne embolije, te je uz ranu mobilizaciju bolesnika predložena i profilaksa heparinom u cilju smanjenja incidencije, ova bolest je i dalje značajan klinički i epidemiološki problem s visokom smrtnošću. Dijagnostički postupak ne smije odlagati početak liječenja

The Epidemiology and Diagnostic Approach to Acute Pulmonary Embolism in the University Hospital

The aim of this retrospective study was to evaluate the demographics and clinical characteristics of patients with pulmonary embolism treated in medical intensive care unit (ICU) at the University Hospital during a six-year period, and to assess the impact of several risk factors on patients’ survival. The study included 165 patients, mean age 69.3 ± 13.7 years, predominantly female (70.3%). Dominant symptom was dyspnea (97.0%), the most common sign tachypnea (69.6%). Pulmonary embolism was confirmed by high-probability ventilation/perfusion lung scan or multidetector computed tomography in 71.5% and was regarded as massive in 63 (38.2%), submassive in 23 (13.9%) and non massive in 79 patients (47.9%). Mean hospital stay was 5.7 ± 4.4 days for ICU, and 14.8 ± 9.1 days, overall. The ICU mortality was 26.7% and in-hospital mortality 30.9%. No statistical difference in mortality between male and female patients was observed (30.6% and 31.0%, respectively; p=0.965), but prolonged immobilization (p=0.002), recent operation (p=0.034) or malignancy (p=0.009) were shown to influence the outcome. Although a number of risk factors for developing pulmonary embolism have been identified and heparin prophylaxis along with early mobilization proposed to reduce the incidence, pulmonary embolism remains an important clinical problem with high mortality rate. The diagnostics should not wait and the therapy should start as soon as possible

Epidemiološki pokazatelji i dijagnostički pristup bolesniku s akutnom plućnom embolijom u kliničkoj bolnici

The aim of this retrospective study was to evaluate the demographics and clinical characteristics of patients with pulmonary embolism treated in medical intensive care unit (ICU) at the University Hospital during a six-year period, and to assess the impact of several risk factors on patients' survival. The study included 165 patients, mean age 69.3 +/- 13.7 years, predominantly female (70.3%). Dominant symptom was dyspnea (97.0%), the most common sign tachypnea (69.6%). Pulmonary embolism was confirmed by high-probability ventilation/perfusion lung scan or multidetector computed tomography in 71.5% and was regarded as massive in 63 (38.2%), submassive in 23 (13.9%) and non massive in 79 patients (47.9%). Mean hospital stay was 5.7 +/- 4.4 days for ICU, and 14.8 +/- 9.1 days, overall. The ICU mortality was 26.7% and in-hospital mortality 30.9%. No statistical difference in mortality between male and female patients was observed (30.6% and 31.0%, respectively; p = 0.965), but prolonged immobilization (p = 0.002), recent operation (p = 0.034) or malignancy (p = 0.009) were shown to influence the outcome. Although a number of risk factors for developing pulmonary embolism have been identified and heparin prophylaxis along with early mobilization proposed to reduce the incidence, pulmonary embolism remains an important clinical problem with high mortality rate. The diagnostics should not wait and the therapy should start as soon as possible.Cilj ove retrospektivne studije bio je procijeniti demografske i kliničke karakteristike bolesnika s plućnom embolijom liječenih u internističkoj jedinici intenzivnog liječenja (JIL) u Kliničkoj bolnici tijekom šestogodišnjeg perioda, s procjenom značaja pojedinih rizičnih čimbenika na njihovo preživljenje. U studiju je uključeno 165 bolesnika, prosječne dobi 69,3 ± 13,7 godina, 70,3% ispitivane populacije su činile žene. Kao najčešći simptom zabilježena je dispneja (97,0%), a kao najčešći klinički znak tahipneja (69,6%). Plućna je embolija dokazana ventilacijsko-perfuzijskom scintigrafijom pluća ili multidetektorskom kompjuteriziranom tomografijom u 71,5% bolesnika, stratificiranih u skupine s masivnom plućnom embolijom (63 bolesnika – 38,2%), submasivnom (23 bolesnika – 13,9%) i ne masivnom plućnom embolijom (79 bolesnika – 47,9%). Prosječno trajanje liječenja u JIL iznosilo je 5,7 ± 4,4 dana, a ukupno 14,8 ± 9,1 dana. Smrtnost u JIL iznosila je 26,7%, a cjelokupna bolnička smrtnost 30,9%. Nije na|eno statistički značajne razlike u smrtnosti bolesnika po spolu (30,6%:31,0%, p=0,965), dokazan je statistički značajan utjecaj dugotrajne imobilizacije (p=0,002), nedavnog operativnog zahvata (p=0,034) i maligne bolesti (p=0,009) na ishod liječenja. Iako su definirani različiti rizični čimbenici za nastanak plućne embolije, te je uz ranu mobilizaciju bolesnika predložena i profilaksa heparinom u cilju smanjenja incidencije, ova bolest je i dalje značajan klinički i epidemiološki problem s visokom smrtnošću. Dijagnostički postupak ne smije odlagati početak liječenja

Activation of cGAS-STING Pathway Is Associated with MSI-H Stage IV Colorectal Cancer

Colorectal cancer is the second most common cause of cancer-related mortality in adults. Understanding colorectal tumorigenesis at both the cellular and molecular levels is crucial for developing effective treatment options. Forty-one biopsy samples from patients with metastatic CRC (mCRC) were collected at Split University Hospital in Croatia. A total of 41 patients (21 with microsatellite unstable tumours and 20 with microsatellite stable tumours) were randomly included in the study. Immunolabelling of cGAS and STING in metastatic CRC was performed and further complemented by histological classification, tumour grade, and KRAS, NRAS, and BRAF mutational status of mCRC. In bivariate analysis, elevated expression of cGAS and STING was positively associated with MSI-H colon cancer (Fisher’s exact test, both p = 0.0203). Combined expression analysis of cGAS and STING showed a significantly higher percentage of patients with mCRC MSI-H with a fully or partially activated cGAS-STING signalling pathway (chi-square test, p = 0.0050). After adjusting for age, sex, and STING expression, increased cGAS expression remained significantly associated with MSI-H colon cancer in a multiple logistic regression model (β = 1.588, SE = ±0.799, p = 0.047). The cGAS-STING signalling axis represents a compelling new target for optimization of immune checkpoint inhibitor therapeutic approaches in patients with MSI-H stage IV CRC

The dynamics of the inflammatory response during BBN-induced bladder carcinogenesis in mice

BACKGROUND: Bladder cancer (BC) is the most common malignant disease of the urinary tract. Recurrent high grade non muscle invasive BC carries a serious risk for progression and subsequent metastases. The most common preclinical mouse model for bladder cancer relies on administration of N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) to mice. BBN-induced tumors in mice recapitulate the histology of human BC and were characterized with an overexpression of markers typical for basal-like cancer subtype in addition to a high mutational burden with frequent mutations in Trp53, similar to human muscle invasive BC. METHODS: Bladder cancer was induced in C57BL/6J male mice by administering the BBN in the drinking water. A thorough histopathological analysis of bladder specimen during and post BBN treatment was performed at 2, 4, 16, 20 and 25 weeks. RNA sequencing and qPCR was performed to assess the levels of expression of immunologically relevant genes at 2 weeks and 20 weeks during and post BBN treatment. RESULTS: We characterized the dynamics of the inflammatory response in the BBN-induced BC in mice. The treatment with BBN had gradually induced a robust inflammation in the first 2 weeks of administration, however, the inflammatory response was progressively silenced in the following weeks of the treatment, until the progression of the primary carcinoma. Tumors at 20 weeks were characterized with a marked upregulation of IL18 when compared to premalignant inflammatory response at 2 weeks. In accordance with this, we observed an increase in expression of IFNγ-responsive genes coupled to a pronounced lymphocytic infiltrate during the early stages of malignant transformation in bladder. Similar to human basal-like BC, BBN-induced murine tumors displayed an upregulated expression of immunoinhibitory molecules such as CTLA-4, PD-L1, and IDO1 which can lead to cytotoxic resistance and tumor escape. CONCLUSIONS: Despite the recent advances in bladder cancer therapy which include the use of checkpoint inhibitors, the treatment options for patients with locally advanced and metastatic BC remain limited. BBN-induced BC in mice displays an immunological profile which shares similarities with human MIBC thus representing an optimal model for preclinical studies on immunomodulation in management of BC.status: publishe