Explore the vast range of titles available.

ObjectiveSporadic early-onset colorectal cancer (EOCRC) has bad prognosis, yet is poorly represented by cell line models. We examine the key mutational and transcriptomic alterations in an organoid biobank enriched in EOCRCs.DesignWe established paired cancer (n=32) and normal organoids (n=18) from 20 patients enriched in microsatellite-stable EOCRC. Exome and transcriptome analysis was performed.ResultsWe observed a striking diversity of molecular phenotypes, including PTPRK-RSPO3 fusions. Transcriptionally, RSPO fusion organoids resembled normal colon organoids and were distinct from APC mutant organoids, with high BMP2 and low PTK7 expression. Single cell transcriptome analysis confirmed the similarity between RSPO fusion organoids and normal organoids, with a propensity for maturation on Wnt withdrawal, whereas the APC mutant organoids were locked in progenitor stages. CRISPR/Cas9 engineered mutation of APC in normal human colon organoids led to upregulation of PTK7 protein and suppression of BMP2, but less so with an engineered RNF43 mutation. The frequent co-occurrence of RSPO fusions with SMAD4 or BMPR1A mutation was confirmed in TCGA database searches. RNF43 mutation was found in organoid from a leukaemia survivor with a novel mutational signature; and organoids with POLE proofreading mutation displayed ultramutation. The cancer organoid genomes were stable over long culture periods, while normal human colon organoids tended to be subject to clonal dominance over time.ConclusionsThese organoid models enriched in EOCRCs with linked genomic data fill a gap in existing CRC models and reveal distinct genetic profiles and novel pathway cooperativity.

Suet Yi Leung, Mao Mao and colleagues report whole-genome sequencing of 100 gastric cancers and DNA copy number, gene expression and methylation profiling of these tumors. They identify new recurrently mutated genes and find mutation of RHOA in 14% of diffuse-type gastric cancers. Gastric cancer is a heterogeneous disease with diverse molecular and histological subtypes. We performed whole-genome sequencing in 100 tumor-normal pairs, along with DNA copy number, gene expression and methylation profiling, for integrative genomic analysis. We found subtype-specific genetic and epigenetic perturbations and unique mutational signatures. We identified previously known ( TP53 , ARID1A and CDH1 ) and new ( MUC6 , CTNNA2 , GLI3 , RNF43 and others) significantly mutated driver genes. Specifically, we found RHOA mutations in 14.3% of diffuse-type tumors but not in intestinal-type tumors ( P < 0.001). The mutations clustered in recurrent hotspots affecting functional domains and caused defective RHOA signaling, promoting escape from anoikis in organoid cultures. The top perturbed pathways in gastric cancer included adherens junction and focal adhesion, in which RHOA and other mutated genes we identified participate as key players. These findings illustrate a multidimensional and comprehensive genomic landscape that highlights the molecular complexity of gastric cancer and provides a road map to facilitate genome-guided personalized therapy.

BackgroundGastric intestinal metaplasia (IM) is a precancerous stage spanning a morphological spectrum that is poorly represented by human cell line models.ObjectiveWe aim to establish and characterise human IM cell models to better understand IM progression along the cancer spectrum.DesignA large human gastric IM organoid (IMO) cohort (n=28), their clonal derivatives and normal gastric organoids (n=42) for comparison were established. Comprehensive multi-omics profiling and functional characterisation were performed.ResultsSingle-cell transcriptomes revealed IMO cells spanning a spectrum from hybrid gastric/intestinal to advanced intestinal differentiation. Their lineage trajectories connected different cycling and quiescent stem and progenitors, highlighting differences in gastric to IM transition and the potential origin of IM from STMN1 cycling isthmus stem cells. Hybrid IMOs showed impaired differentiation potential, high lineage plasticity beyond gastric or intestinal fates and reactivation of a fetal gene programme.Cell populations in gastric IM and cancer tissues were highly similar to those derived from IMOs and exhibited a fetal signature. Genomically, IMOs showed elevated mutation burden, frequent chromosome 20 gain and epigenetic deregulation of many intestinal and gastric genes. Functionally, IMOs were FGF10 independent and showed downregulated FGFR2. Several IMOs exhibited a cell-matrix adhesion independent subpopulation that displayed chromosome 20 gain but lacked key cancer driver mutations, potentially representing the earliest neoplastic precursor of IM-induced gastric cancer.ConclusionsOverall, our IMO biobank captured the heterogeneous nature of IM, revealing mechanistic insights on IM pathogenesis and progression, offering an ideal platform for studying early gastric neoplastic transformation and chemoprevention.

ObjectiveCell-cell (CC) and cell-matrix (CM) adhesions are essential for epithelial cell survival, yet dissociation-induced apoptosis is frequently circumvented in malignant cells.DesignWe explored CC and CM dependence in 58 gastric cancer (GC) organoids by withdrawing either ROCK inhibitor, matrix or both to evaluate their tumorigenic potential in terms of apoptosis resistance, correlation with oncogenic driver mutations and clinical behaviour. We performed mechanistic studies to determine the role of diffuse-type GC drivers: ARHGAP fusions, RHOA and CDH1, in modulating CC (CCi) or CM (CMi) adhesion independence.Results97% of the tumour organoids were CMi, 66% were CCi and 52% were resistant to double withdrawal (CCi/CMi), while normal organoids were neither CMi nor CCi. Clinically, the CCi/CMi phenotype was associated with an infiltrative tumour edge and advanced tumour stage. Moreover, the CCi/CMi transcriptome signature was associated with poor patient survival when applied to three public GC datasets. CCi/CMi and CCi phenotypes were enriched in diffuse-type GC organoids, especially in those with oncogenic driver perturbation of RHO signalling via RHOA mutation or ARHGAP fusions. Inducible knockout of ARHGAP fusions in CCi/CMi tumour organoids led to resensitisation to CC/CM dissociation-induced apoptosis, upregulation of focal adhesion and tight junction genes, partial reversion to a more normal cystic phenotype and inhibited xenograft formation. Normal gastric organoids engineered with CDH1 or RHOA mutations became CMi or CCi, respectively.ConclusionsThe CCi/CMi phenotype has a critical role in malignant transformation and tumour progression, offering new mechanistic information on RHO-ROCK pathway inhibition that contributes to GC pathogenicity.

Antimicrobial stewardship program (ASP) interventions, such as prospective audit and feedback (PAF), have been shown to reduce antimicrobial use and improve patient outcomes. However, the optimal approach to PAF is unknown. We examined the impact of a high-intensity interdisciplinary rounds-based PAF compared to low-intensity PAF on antimicrobial use on internal medicine wards in a 400-bed community hospital. Prior to the intervention, ASP pharmacists performed low-intensity PAF with a focus on targeted antibiotics. Recommendations were made directly to the internist for each patient. High-intensity, rounds-based PAF was then introduced sequentially to 5 internal medicine wards. This PAF format included twice-weekly interdisciplinary rounds, with a review of all internal medicine patients receiving any antimicrobial agent. Antibiotic use and clinical outcomes were measured before and after the transition to high-intensity PAF. An interrupted time-series analysis was performed adjusting for seasonal and secular trends. With the transition from low-intensity to high-intensity PAF, a reduction in overall usage was seen from 483 defined daily doses (DDD)/1,000 patient days (PD) during the low-intensity phase to 442 DDD/1,000 PD in the high-intensity phase (difference, -42; 95% confidence interval [CI], -74 to -9). The reduction in usage was more pronounced in the adjusted analysis, in the latter half of the high intensity period, and for targeted agents. There were no differences seen in clinical outcomes in the adjusted analysis. High-intensity PAF was associated with a reduction in antibiotic use compared to a low-intensity approach without any adverse impact on patient outcomes. A decision to implement high-intensity PAF approach should be weighed against the increased workload required.

A central mechanism of tumour progression and metastasis involves the generation of an immunosuppressive ‘macroenvironment’ mediated in part through tumour-secreted factors. Here we demonstrate that upregulation of the Inhibitor of Differentiation 1 (Id1), in response to tumour-derived factors, such as TGFβ, is responsible for the switch from dendritic cell (DC) differentiation to myeloid-derived suppressor cell expansion during tumour progression. Genetic inactivation of Id1 largely corrects the myeloid imbalance, whereas Id1 overexpression in the absence of tumour-derived factors re-creates it. Id1 overexpression leads to systemic immunosuppression by downregulation of key molecules involved in DC differentiation and suppression of CD8 T-cell proliferation, thus promoting primary tumour growth and metastatic progression. Furthermore, advanced melanoma patients have increased plasma TGFβ levels and express higher levels of ID1 in myeloid peripheral blood cells. This study reveals a critical role for Id1 in suppressing the anti-tumour immune response during tumour progression and metastasis. Tumour progression is promoted by the generation of an immunosuppressive macroenvironment. Here, the authors demonstrate that the Inhibitor of Differentiation 1 promotes the switch from dendritic cell differentiation towards myeloid-derived suppressor cell expansion during tumour progression.

Introduction High-dose methotrexate, defined as dose ≥1 g/m2, is commonly used in chemotherapy protocols. Certain drugs such as acyclovir, allopurinol, proton pump inhibitors and some antibiotics have been associated with delayed renal clearance of methotrexate and may predispose patients to toxicities. Currently, no specific recommendations exist on adjusting the high-dose methotrexate regimen in the presence of potential interacting drugs. This study aims to determine whether presence of interacting drugs is associated with delayed methotrexate clearance. Methods This was a case-control study of adult oncology patients who received their first cycle of high-dose methotrexate. Cases were defined as patients who experienced delayed methotrexate clearance, as indicated by serum methotrexate level ≥ 0.1 umol/L at 72 h. The primary endpoint was the frequency of presence of interacting drugs between cases and controls. These were compared using Fisher's exact test. Where possible, adjustment for significant baseline differences that can affect methotrexate clearance was made using logistic regression. The secondary endpoint was frequency of methotrexate-related clinical toxicities between groups and included myelosuppression, nephrotoxicity, hepatotoxicity and mucositis. Results From January 2004 to March 2011, 73 patients met study criteria, of which 23 were defined as cases. Significant baseline differences were methotrexate dose received (9116 mg ± 4339 versus 6054 mg ± 2874, p=0.012) and renal impairment (5 versus 0, p = 0.002). The presence of interacting drugs was not associated with delayed methotrexate clearance (OR 0.91, 95% CI 0.24–3.38, p > 0.999). After adjusting for methotrexate dose, drugs observed more frequently (allopurinol, proton pump inhibitors and sulfamethoxazole/trimethoprim) were not associated with delayed methotrexate clearance (p = 0.95, 0.59 and 0.20, respectively). Cases experienced more severe anemia (grade 2.52 versus 1.68, p = 0.007) and higher rates of mucositis (65.2% versus 20.0%, p < 0.001). Conclusion This study showed no significant association between presence of interacting drugs and delayed methotrexate clearance. Patients who experienced delayed methotrexate clearance had higher incidence of severe anemia and mucositis.

To describe the evolution of respiratory antibiotic prescribing during the coronavirus disease 2019 (COVID-19) pandemic across 3 large hospitals that maintained antimicrobial stewardship services throughout the pandemic. Retrospective interrupted time-series analysis. A multicenter study was conducted including medical and intensive care units (ICUs) from 3 hospitals within a Canadian epicenter for COVID-19. Interrupted time-series analysis was used to analyze rates of respiratory antibiotic utilization measured in days of therapy per 1,000 patient days (DOT/1,000 PD) in medical units and ICUs. Each of the first 3 waves of the pandemic were compared to the baseline. Within the medical units, use of respiratory antibiotics increased during the first wave of the pandemic (rate ratio [RR], 1.76; 95% CI, 1.38-2.25) but returned to the baseline in waves 2 and 3 despite more COVID-19 admissions. In ICU, the use of respiratory antibiotics increased in wave 1 (RR, 1.30; 95% CI, 1.16-1.46) and wave 2 of the pandemic (RR, 1.21; 95% CI, 1.11-1.33) and returned to the baseline in the third wave, which had the most COVID-19 admissions. After an initial surge in respiratory antibiotic prescribing, we observed the normalization of prescribing trends at 3 large hospitals throughout the COVID-19 pandemic. This trend may have been due to the timely generation of new research and guidelines developed with frontline clinicians, allowing for the active application of new research to clinical practice.

We evaluated the impact of introducing a mandatory indication field into electronic order entry for targeted antibiotics in adult inpatients. Retrospective, before-and-after trial. A 400-bed community hospital. All adult electronic intravenous (IV) and enteral orders for targeted antibiotics (moxifloxacin, ciprofloxacin, clindamycin, vancomycin, and metronidazole) had a mandatory indication field added. Control antibiotics (amoxicillin-clavulanate, ceftriaxone and piperacillin-tazobactam) were chosen to track shifts in antibiotic prescribing due to the introduction of mandatory indication field. Descriptive statistics were used to summarize the primary outcome, measured in Defined Daily Doses (DDD) per 1000 patient days (PD). Interrupted time-series (ITS) analysis was performed to compare levels and trends in antibiotic usage of targeted and control antibiotics during 24 months before and after the intervention. Additionally, a descriptive analysis of mandatory indication fields for targeted antibiotics in the postintervention period was conducted. In total, 4,572 study antibiotic orders were evaluated after the intervention. Preset mandatory indications were selected for 30%-55% of orders. There was decreased usage of targeted antibiotics (mean, 92.02 vs 72.07 DDD/1000-PD) with increased usage of control antibiotics (mean, 102.73 vs 119.91 DDD/1000-PD). ITS analysis showed no statistically significant difference in overall antibiotic usage before and after the intervention for all targeted antibiotics. This study showed moderate use of preset mandatory indications, suggesting that the preset list of indications can be optimized. There was no impact on overall antibiotic usage with the use of mandatory indications. More prospective research is needed to study the utility of this intervention in different contexts.