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Long-term survival after lung transplantation remains limited by chronic lung allograft dysfunction (CLAD). CLAD has 2 histologic phenotypes, namely obliterative bronchiolitis (OB) and restrictive alveolar fibroelastosis (AFE), which have distinct clinical presentations, pathologies, and outcomes. Understanding of OB versus AFE pathogenesis would improve with better animal models.We utilized a ferret orthotopic single-lung transplantation model to characterize allograft fibrosis as a histologic measure of CLAD. Native lobes and "No CLAD" allografts lacking aberrant histology were used as controls. We used morphometric analysis to evaluate the size and abundance of B-cell aggregates and tertiary lymphoid organs (TLOs) and their cell composition. Quantitative RNA expression of 47 target genes was performed simultaneously using a custom QuantiGene Plex Assay.Ferret lung allografts develop the full spectrum of human CLAD histology including OB and AFE subtypes. While both OB and AFE allografts developed TLOs, TLO size and number were greater with AFE histology. More activated germinal center cells marked by B-cell lymphoma 6 Transcription Repressor, (B-cell lymphoma 6) expression and fewer cells expressing forkhead box P3 correlated with AFE, congruent with greater diffuse immunoglobulin, plasma cell abundance, and complement 4d staining. Furthermore, forkhead box P3 RNA induction was significant in OB allografts specifically. RNA expression changes were seen in native lobes of animals with AFE but not OB when compared with No CLAD native lobes.The orthotopic ferret single-lung transplant model provides unique opportunities to better understand factors that dispose allografts to OB versus AFE. This will help develop potential immunomodulatory therapies and antifibrotic approaches for lung transplant patients.

Tracheal grafts may be necessary to bridge long-segment defects after curative resection for airway obstructions. Bioengineered grafts have emerged as an appealing option, given the possibilities of altering the histologic and cellular profile of the conduit. We previously designed a bioreactor capable of luminally decellularizing and recellularizing a ferret trachea with surface airway epithelia (SAE) basal cells (BCs), and we sought to assess the fate of these grafts when transplanted in an orthotopic fashion. As adjuncts to the procedure, we investigated the use of a vascular endothelial growth factor (VEGF)-laden hydrogel and of immunosuppression (IS) in graft revascularization and viability. IS was shown to limit early graft revascularization, but this effect could be counteracted with VEGF supplementation. Submucosal gland (SMG) loss was shown to be inevitable regardless of the revascularization strategy. Lastly, the bioengineered tracheas survived one month after transplant with differentiation of our implanted BCs that then transitioned into a recipient-derived functional epithelium. The work presented in this manuscript has important implications for future cellular and regenerative therapies.

Related Article from Two Sides of the Same Coin: EGFR Exon 19 Deletions and Insertions in Lung Cancer

Most lung adenocarcinoma-associated EGF receptor (EGFR) mutations confer sensitivity to specific EGFR tyrosine kinase inhibitors. The finding that exon 19 insertion mutations are also sensitive to this class of drugs suggests that testing for these mutations should be done and that these patients will benefit from treatment with tyrosine kinase inhibitors. Clin Cancer Res; 18(6); 1490–2. ©2012 AACR.

Lung transplantation is an acceptable and potentially life-saving treatment option for coronavirus disease 2019 (COVID-19)-induced acute respiratory distress syndrome and pulmonary fibrosis. This study was conducted to determine whether recipients of lung transplantation (LT) for COVID-19-related lung disease have comparable outcomes to other recipients with a similar level of lung dysfunction.The Organ Procurement and Transplant Network database was queried for adult LT candidates between 2006 and 2021. Recipients with COVID-19-related respiratory failure were matched 1:2 using a nearest-neighbor algorithm. Kaplan-Meier methods with log-rank tests were used to compare long-term survival. A proportional hazards model was used to calculate risk of death.A total of 37,333 LT candidates from all causes were compared with 334 candidates from COVID-19-related respiratory failure. COVID-19 recipients were more likely to be younger (50 vs 57 years, P.001), male (79% vs 60%, P.001), require extracorporeal membrane oxygenation (56.3% vs 4.0%, P.001), and have worse lung function (lung allocation score, 82.4 vs 47.8; P.001) at transplantation. Subsequently, 227 COVID-19 recipients were matched with 454 controls. Patients who received a transplant for COVID-19 had similar rates of mechanical ventilation, extracorporeal membrane oxygenation, postoperative complications, and functional status at discharge compared with controls. There was no difference in overall survival or risk of death from COVID-19 (hazard ratio, 0.82; 95% CI, 0.45-1.53; P = .54).Six-month survival for recipients of LT for COVID-19-related respiratory failure was comparable to that of other LT recipients.

Cartilaginous airways of larger mammals and the mouse trachea contain at least 3 well-established stem cell compartments, including basal cells of the surface airway epithelium (SAE) and ductal and myoepithelial cells of the submucosal glands (SMG). Here we demonstrate that glandular Sox9-expressing progenitors capable of SAE repair decline with age in mice. Notably, Sox9-lineage glandular progenitors produced basal and ciliated cells in the SAE, but failed to produce secretory cells. Lef1 was required for glandular Sox9 lineage contribution to SAE repair, and its deletion significantly reduced proliferation following injury. By contrast, in vivo deletion of Sox9 enhanced proliferation of progenitors in both the SAE and SMG shortly following injury, but these progenitors failed to proliferate in vitro in the absence of Sox9, similar to that previously shown for Lef1 deletion. In cystic fibrosis ferret airways, Sox9 expression inversely correlated with Ki67 proliferative marker expression in SMG and the SAE. Using in vitro and ex vivo models, we demonstrate that Sox9 is extinguished as glandular progenitors exit ducts and proliferate on the airway surface and that Sox9 is required for migration and proper differentiation of SMG, but not surface airway, progenitors. We propose a model whereby Wnt/Lef1 and Sox9 signals differentially regulate the proliferative and migratory behavior of glandular progenitors, respectively.

Genome editing in the lung has the potential to provide long-term expression of therapeutic protein to treat lung genetic diseases. Yet efficient delivery of CRISPR to the lung remains a challenge. The NIH Somatic Cell Genome Editing (SCGE) Consortium is developing safe and effective methods for genome editing in disease tissues. Methods developed by consortium members are independently validated by the SCGE small animal testing center to establish rigor and reproducibility. We have developed and validated a dual adeno-associated virus (AAV) CRISPR platform that supports effective editing of a lox-stop-lox-Tomato reporter in mouse lung airway. After intratracheal injection of the AAV serotype 5 (AAV5)-packaged S. pyogenes Cas9 (SpCas9) and single guide RNAs (sgRNAs), we observed ∼19%–26% Tomato-positive cells in both large and small airways, including club and ciliated epithelial cell types. This highly effective AAV delivery platform will facilitate the study of therapeutic genome editing in the lung and other tissue types.

The mammalian airways are lined by a continuous epithelial layer that is maintained by diverse populations of resident multipotent stem cells. These stem cells are responsible for replenishing the epithelium both at homeostasis and following injury, making them promising targets for stem cell and genetic-based therapies for a variety of respiratory diseases. However, the mechanisms that regulate when and how these stem cells proliferate, migrate, and differentiate remains incompletely understood. Here, we find that the high mobility group (HMG) domain transcription factor Lef-1 regulates proliferation and differentiation of mouse tracheal basal cells. We demonstrate that conditional deletion of Lef-1 stalls basal cell proliferation at the G1/S transition of the cell cycle, and that Lef-1 knockout cells are unable to maintain luminal tracheal cell types in long-term air-liquid interface culture. RNA sequencing analysis revealed that Lef-1 knockout (Lef-1KO) results in downregulation of key DNA damage response and cell cycle progression genes, including the kinase Chek1. Furthermore, chemical inhibition of Chek1 is sufficient to stall basal cell self-renewal in a similar fashion as Lef-1 deletion. Notably, the cell cycle block imposed by Lef-1KO in vitro is transient and basal cells eventually compensate to proliferate normally in a Chek1-independent manner. Finally, Lef-1KO cells were unable to fully regenerate tracheal epithelium following injury in vivo. These findings reveal that Lef-1 is essential for proper basal cell function. Thus, modulating Lef-1 function in airway basal cells may have applications in regenerative medicine. © AlphaMed Press 2021 SIGNIFICANCE STATEMENT: Airway basal cells (BCs) are the primary progenitor cells of the conducting airway epithelium and thus are promising targets for durable genetic- and cell-based therapies of lung diseases such as cystic fibrosis. However, the mechanisms that govern their regenerative abilities are not fully understood. The authors' show that Lef-1, an effector of Wnt signaling, is critical for BC cell cycle progression through G1/S and influences BC differentiation in vitro. Loss of Lef-1 significantly reduces the capacity of BC to regenerate the tracheal epithelium in vivo following injury. Manipulating Lef-1 expression in BCs may provide opportunities to modulate the regenerative capacity of BCs and their progeny.

Ferrets are an attractive mammalian model for several diseases, especially those affecting the lungs, liver, brain, and kidneys. Many chronic human diseases have been difficult to model in rodents due to differences in size and cellular anatomy. This is particularly the case for the lung, where ferrets provide an attractive mammalian model of both acute and chronic lung diseases, such as influenza, cystic fibrosis, A1A emphysema, and obliterative bronchiolitis, closely recapitulating disease pathogenesis, as it occurs in humans. As such, ferrets have the potential to be a valuable preclinical model for the evaluation of cell-based therapies for lung regeneration and, likely, for other tissues. Induced pluripotent stem cells (iPSCs) provide a great option for provision of enough autologous cells to make patient-specific cell therapies a reality. Unfortunately, they have not been successfully created from ferrets. In this study, we demonstrate the generation of ferret iPSCs that reflect the primed pluripotent state of human iPSCs. Ferret fetal fibroblasts were reprogrammed and acquired core features of pluripotency, having the capacity for self-renewal, multilineage differentiation, and a high-level expression of the core pluripotency genes and pathways at both the transcriptional and protein level. In conclusion, we have generated ferret pluripotent stem cells that provide an opportunity for advancing our capacity to evaluate autologous cell engraftment in ferrets.

To review direct comparative studies of the gonadotrophin-releasing hormone (GnRH) agonists goserelin, triptorelin, and leuprorelin for the treatment of prostate cancer, and identify whether there are meaningful clinical differences between these agents. In June 2017, the following searches were performed independently by two reviewers in PubMed: (i) 'prostate cancer' and 'triptorelin' and 'leuprorelin', (ii) 'prostate cancer' and 'triptorelin' and 'goserelin', and (iii) 'prostate cancer' and 'goserelin' and 'leuprorelin', without time restriction. Duplicates were deleted. Relevant conference abstracts were also screened. A total of 16 direct comparative trials were identified: 12 reported on efficacy outcomes, four on safety/tolerability, and five on the convenience of administration/user perceptions. These studies are restricted in terms of patient numbers, formulations assessed, and endpoints measured; none were adequately powered for survival outcome measures. Studies reporting on efficacy endpoints did not show major differences in the ability of these GnRH agonists to reduce levels of testosterone or prostate-specific antigen. Some studies suggest differences in short- or long-term testosterone control, the rate of injection site adverse events, and patient/healthcare professional perceptions, but definitive conclusions cannot be drawn from the existing evidence. Few direct comparative trials of GnRH agonists have been conducted. Whilst GnRH agonists provide a similar castration effect, there is not enough evidence to show that GnRH agonists are equivalent.

The Notch pathway is a highly conserved pathway increasingly implicated with the progression of human cancers. Of the four existing receptors associated with the pathway, the deregulation in the expression of the Notch-3 receptor is associated with more aggressive disease and poor prognosis. Selective targeting of this receptor has the potential to enhance current anti-cancer treatments. Molecular profiling strategies are increasingly incorporated into clinical decision making. This review aims to evaluate the clinical potential of Notch-3 within this new era of personalised medicine.

Airway submucosal glands (SMGs) are facultative stem cell niches for the surface epithelium, but the phenotype of the SMG-derived progenitor cells remains unclear. In other organs, glandular myoepithelial cells (MECs) have been proposed to be multipotent progenitors for luminal cells. We sought to determine the developmental phase during which mouse tracheal glandular MECs are born and whether these MECs are progenitors for other cell phenotypes during SMG morphogenesis. To approach this question, we localized two MEC protein markers (α-smooth muscle actin [αSMA/ACTA2] and smooth muscle myosin heavy chain 11 [SMMHC/MYH11]) during various stages of SMG development (placode, elongation, branching, and differentiation) and used ACTA2-CreERT2 and MYH11-CreERT2 transgenic mice to fate map MEC-derived lineages during SMG morphogenesis. Both αSMA- and SMMHC-expressing cells emerged early after placode formation and during the elongation phase of SMG development. Lineage tracing in newborn mice demonstrated that lineage-positive MECs are born at the tips of invading tubules during the elongation phase of gland development. Lineage-positive MECs born within the first 7 days after birth gave rise to the largest percentage of multipotent progenitors capable of contributing to myoepithelial, serous, mucous, and ductal cell lineages. Serial tamoxifen-induction of both Cre-driver lines demonstrated that lineage-positive multipotent MECs contribute to ∼ 60% of glandular cells by 21 days after birth. In contrast, lineage-traced MECs did not contribute to cell types in the surface airway epithelium. These findings demonstrate that MECs born early during SMG morphogenesis are multipotent progenitors with the capacity to differentiate into other glandular cell types.

Chronic lung diseases are a major global health concern—accounting for approximately 13.5% of all deaths world-wide (1). Lung transplantation is an effective therapy for end-stage lung diseases when medical therapies fail.

Epithelial stem cells reside within multiple regions of the lung where they renew various region-specific cells. In addition, there are multiple routes of regeneration after injury through built-in heterogeneity within stem cell populations and through a capacity for cellular plasticity among differentiated cells. These processes are important facets of respiratory tissue resiliency and organism survival. However, this regenerative capacity is not limitless, and repetitive or chronic injuries, environmental stresses, or underlying factors of disease may ultimately lead to or contribute to tissue remodeling and end-stage lung disease. This chapter will review stem cell heterogeneity among pulmonary epithelia in the lower respiratory system, discuss recent findings that may challenge long-held scientific paradigms, and identify several clinically relevant research opportunities for regenerative medicine.

The domestic ferret (Mustela putorius furo) has proven to be a useful species for modeling human genetic and infectious diseases of the lung and brain. However, biomedical research in ferrets has been hindered by the lack of rapid and cost-effective methods for genome engineering. Here, we utilized CRISPR/Cas9-mediated, homology-independent insertion at the ROSA26 “safe harbor” locus in ferret zygotes and created transgenic animals expressing a dual-fluorescent Cre-reporter system flanked by PhiC31 and Bxb1 integrase attP sites. Out of 151 zygotes injected with circular transgene-containing plasmid and Cas9 protein loaded with the ROSA26 intron-1 sgRNA, there were 23 births of which 5 had targeted integration events (22% efficiency). The encoded tdTomato transgene was highly expressed in all tissues evaluated. Targeted integration was verified by PCR analyses, Southern blot, and germ-line transmission. Function of the ROSA26-CAG-LoxPtdTomatoStopLoxPEGFP (ROSA-TG) Cre-reporter was confirmed in primary cells following Cre expression. The Phi31 and Bxb1 integrase attP sites flanking the transgene will also enable rapid directional insertion of any transgene without a size limitation at the ROSA26 locus. These methods and the model generated will greatly enhance biomedical research involving lineage tracing, the evaluation of stem cell therapy, and transgenesis in ferret models of human disease.

The exact biological mechanism governing the radioresistant phenotype of prostate tumours at a high risk of recurrence despite the delivery of advanced radiotherapy protocols remains unclear. This study analysed the protein expression profiles of a previously generated isogenic 22Rv1 prostate cancer model of radioresistance using DigiWest multiplex protein profiling for a selection of 90 signalling proteins. Comparative analysis of the profiles identified a substantial change in the expression of 43 proteins. Differential PARP-1, AR, p53, Notch-3 and YB-1 protein levels were independently validated using Western Blotting. Pharmacological targeting of these proteins was associated with a mild but significant radiosensitisation effect at 4Gy. This study supports the clinical relevance of isogenic in vitro models of radioresistance and clarifies the molecular radiation response of prostate cancer cells.

Purpose Bevacizumab used in combination with first-line chemotherapy confers an overall survival (OS) benefit for patients with non-squamous non–small-cell lung cancer (NSCLC). This analysis from the ARIES observational cohort study (OCS) was initiated to evaluate the effect of bevacizumab use beyond disease progression (BBP) on clinical outcomes in patients with NSCLC receiving first-line treatment with bevacizumab and chemotherapy. Methods The ARIES OCS prospectively enrolled patients from 2006 to 2009 in the United States who had advanced non-squamous NSCLC, received bevacizumab with chemotherapy in the first-line setting, and survived progressive disease (PD). A dichotomous landmark analysis examined post-PD OS (ppOS) in patients who received BBP versus no BBP within 30 days post PD. A time-dependent Cox model assessed the effect of cumulative BBP exposure on ppOS. Results The ARIES OCS enrolled 1967 patients with first-line NSCLC; 1358 patients had first PD and were alive at the 30-day landmark (351 patients with BBP and 1007 patients with no BBP). The landmark analysis showed that BBP was associated with a lower risk of death (BBP versus No-BBP); hazard ratio [HR], 0.75; 95% confidence interval 0.65–0.86. In the cumulative exposure analysis of 1461 patients who had PD, HRs for ppOS decreased by approximately 4% for each additional 21-day interval of bevacizumab received. Protocol-specified bevacizumab-select adverse events occurred in 14% of BBP patients. Conclusions BBP was associated with a lower risk of death in patients with NSCLC treated with first-line bevacizumab and chemotherapy. Copyright © 2016 John Wiley & Sons, Ltd.

Rationale: Obliterative bronchiolitis (OB) is a major cause of mortality after lung transplantation. Depletion of airway stem cells (SCs) may lead to fibrosis in OB. Objectives: Two major SC compartments in airways are submucosal glands (SMGs) and surface airway p63 (also known as TP63 [tumor protein 63])-positive/K5 (also known as KRT5 [keratin 5])-positive basal cells (BCs). We hypothesized that depletion of these SC compartments occurs in OB. Methods: Ferret orthotopic left lung transplants were used as an experimental model of OB, and findings were corroborated in human lung allografts. Morphometric analysis was performed in ferret and human lungs to evaluate the abundance of SMGs and changes in the expression of phenotypic BC markers in control, lymphocytic bronchiolitis, and OB airways. The abundance and proliferative capacity of proximal and distal airway SCs was assessed using a clonogenic colony-forming efficiency assay. Measurements and Main Results: Ferret allografts revealed significant loss of SMGs with development of OB. A progressive decline in p63(+)/K5(+) and increase in K5(+)/K14(+) and K14(+) BC phenotypes correlated with the severity of allograft rejection in large and small ferret airways. The abundance and proliferative capacity of basal SCs in large allograft airways declined with severity of OB, and there was complete ablation of basal SCs in distal OB airways. Human allografts mirrored phenotypic BC changes observed in the ferret model. Conclusions: SMGs and basal SC compartments are depleted in large and/or small airways of lung allografts, and basal SC proliferative capacity declines with progression of disease and phenotypic changes. Global airway SC depletion may be a mechanism for pulmonary allograft failure.

Summary The mouse trachea is thought to contain two distinct stem cell compartments that contribute to airway repair—basal cells in the surface airway epithelium (SAE) and an unknown submucosal gland (SMG) cell type. Whether a lineage relationship exists between these two stem cell compartments remains unclear. Using lineage tracing of glandular myoepithelial cells (MECs), we demonstrate that MECs can give rise to seven cell types of the SAE and SMGs following severe airway injury. MECs progressively adopted a basal cell phenotype on the SAE and established lasting progenitors capable of further regeneration following reinjury. MECs activate Wnt-regulated transcription factors (Lef-1/TCF7) following injury and Lef-1 induction in cultured MECs promoted transition to a basal cell phenotype. Surprisingly, dose-dependent MEC conditional activation of Lef-1 in vivo promoted self-limited airway regeneration in the absence of injury. Thus, modulating the Lef-1 transcriptional program in MEC-derived progenitors may have regenerative medicine applications for lung diseases.

Background Lung squamous cell carcinoma (LUSC) accounts for 20–30% of non-small cell lung cancers (NSCLCs). There are limited treatment strategies for LUSC in part due to our inadequate understanding of the molecular underpinnings of the disease. We performed whole-exome sequencing (WES) and comprehensive immune profiling of a unique set of clinically annotated early-stage LUSCs to increase our understanding of the pathobiology of this malignancy. Methods Matched pairs of surgically resected stage I-III LUSCs and normal lung tissues (n = 108) were analyzed by WES. Immunohistochemistry and image analysis-based profiling of 10 immune markers were done on a subset of LUSCs (n = 91). Associations among mutations, immune markers and clinicopathological variables were statistically examined using analysis of variance and Fisher’s exact test. Cox proportional hazards regression models were used for statistical analysis of clinical outcome. Results This early-stage LUSC cohort displayed an average of 209 exonic mutations per tumor. Fourteen genes exhibited significant enrichment for somatic mutation: TP53, MLL2, PIK3CA, NFE2L2, CDH8, KEAP1, PTEN, ADCY8, PTPRT, CALCR, GRM8, FBXW7, RB1 and CDKN2A. Among mutated genes associated with poor recurrence-free survival, MLL2 mutations predicted poor prognosis in both TP53 mutant and wild-type LUSCs. We also found that in treated patients, FBXW7 and KEAP1 mutations were associated with poor response to adjuvant therapy, particularly in TP53-mutant tumors. Analysis of mutations with immune markers revealed that ADCY8 and PIK3CA mutations were associated with markedly decreased tumoral PD-L1 expression, LUSCs with PIK3CA mutations exhibited elevated CD45ro levels and CDKN2A-mutant tumors displayed an up-regulated immune response. Conclusion(s) Our findings pinpoint mutated genes that may impact clinical outcome as well as personalized strategies for targeted immunotherapies in early-stage LUSC.

Multiple distinct epithelial domains are found throughout the airway that are distinguishable by location, structure, function, and cell-type composition. Several progenitor cell populations in the proximal airway have been identified to reside in confined microenvironmental niches including the submucosal glands (SMGs), which are embedded in the tracheal connective tissue between the surface epithelium and cartilage, and basal cells that reside within the surface airway epithelium (SAE). Current research suggests that regulatory pathways that coordinate development of the proximal airway and establishment of progenitor cell niches may overlap with pathways that control progenitor cell responses during airway regeneration following injury. SMGs have been shown to harbor epithelial progenitor cells, and this niche is dysregulated in diseases such as cystic fibrosis. However, mechanisms that regulate progenitor cell proliferation and maintenance within this glandular niche are not completely understood. Here we discuss glandular progenitor cells during development and regeneration of the proximal airway and compare properties of glandular progenitors to those of basal cell progenitors in the SAE. Further investigation into glandular progenitor cell control will provide a direction for interrogating therapeutic interventions to correct aberrant conditions affecting the SMGs in diseases such as cystic fibrosis, chronic bronchitis, and asthma.

Cystic fibrosis (CF) is a multiorgan disease caused by loss of a functional cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel in many epithelia of the body. Here we report the pathology observed in the gastrointestinal organs of juvenile to adult CFTR-knockout ferrets. CF gastrointestinal manifestations included gastric ulceration, intestinal bacterial overgrowth with villous atrophy, and rectal prolapse. Metagenomic phylogenetic analysis of fecal microbiota by deep sequencing revealed considerable genotype-independent microbial diversity between animals, with the majority of taxa overlapping between CF and non-CF pairs. CF hepatic manifestations were variable, but included steatosis, necrosis, biliary hyperplasia, and biliary fibrosis. Gallbladder cystic mucosal hyperplasia was commonly found in 67% of CF animals. The majority of CF animals (85%) had pancreatic abnormalities, including extensive fibrosis, loss of exocrine pancreas, and islet disorganization. Interestingly, 2 of 13 CF animals retained predominantly normal pancreatic histology (84% to 94%) at time of death. Fecal elastase-1 levels from these CF animals were similar to non-CF controls, whereas all other CF animals evaluated were pancreatic insufficient (

Tracheobronchial submucosal glands (SMGs) are derived from one or more multipotent glandular stem cells that coalesce to form a placode in surface airway epithelium (SAE). Wnt/β-catenin-dependent induction of lymphoid enhancer factor ( Lef-1) gene expression during placode formation is an early event required for SMG morphogenesis. We discovered that Sox2 expression is repressed as Lef-1 is induced within airway SMG placodes. Deletion of Lef-1 did not activate Sox2 expression in SMG placodes, demonstrating that Lef-1 activation does not directly inhibit Sox2 expression. Repression of Sox2 protein in SMG placodes occurred posttranscriptionally, since the activity of its endogenous promoter remained unchanged in SMG placodes. Thus we hypothesized that Sox2 transcriptionally represses Lef-1 expression in the SAE and that suppression of Sox2 in SMG placodes activates Wnt/β-catenin-dependent induction of Lef-1 during SMG morphogenesis. Consistent with this hypothesis, transcriptional reporter assays, ChIP analyses, and DNA-protein binding studies revealed a functional Sox2 DNA binding site in the Lef-1 promoter that is required for suppressing β-catenin-dependent transcription. In polarized primary airway epithelium, Wnt induction enhanced Lef-1 expression while also inhibiting Sox2 expression. Conditional deletion of Sox2 also enhanced Lef-1 expression in polarized primary airway epithelium, but this induction was significantly augmented by Wnt stimulation. Our findings provide the first evidence that Sox2 acts as a repressor to directly modulate Wnt-responsive transcription of the Lef-1 gene promoter. These studies support a model whereby Wnt signals and Sox2 dynamically regulate the expression of Lef-1 in airway epithelia and potentially also during SMG development.

Chronic bacterial lung infections in cystic fibrosis (CF) are caused by defects in the CF transmembrane conductance regulator chloride channel. Previously, we described that newborn CF transmembrane conductance regulator–knockout ferrets rapidly develop lung infections within the first week of life. Here, we report a more slowly progressing lung bacterial colonization phenotype observed in juvenile to adult CF ferrets reared on a layered antibiotic regimen. Even on antibiotics, CF ferrets were still very susceptible to bacterial lung infection. The severity of lung histopathology ranged from mild to severe, and variably included mucus obstruction of the airways and submucosal glands, air trapping, atelectasis, bronchopneumonia, and interstitial pneumonia. In all CF lungs, significant numbers of bacteria were detected and impaired tracheal mucociliary clearance was observed. Although Streptococcus, Staphylococcus, and Enterococcus were observed most frequently in the lungs of CF animals, each animal displayed a predominant bacterial species that accounted for over 50% of the culturable bacteria, with no one bacterial taxon predominating in all animals. Matrix-assisted laser desorption–ionization time-of-flight mass spectrometry fingerprinting was used to quantify lung bacteria in 10 CF animals and demonstrated Streptococcus, Staphylococcus, Enterococcus, or Escherichia as the most abundant genera. Interestingly, there was significant overlap in the types of bacteria observed in the lung and intestine of a given CF animal, including bacterial taxa unique to the lung and gut of each CF animal analyzed. These findings demonstrate that CF ferrets develop lung disease during the juvenile and adult stages that is similar to patients with CF, and suggest that enteric bacterial flora may seed the lung of CF ferrets.

As the leading culprit in cancer incidence for American men, prostate cancer continues to pose significant diagnostic, prognostic, and therapeutic tribulations for clinicians. The vast spectrum of disease behavior warrants better molecular classification to facilitate the development of more robust biomarkers that can identify the more aggressive and clinically significant tumor subtypes that require treatment. The untranslated portion of the human transcriptome, namely noncoding RNAs (ncRNA), is emerging as a key player in cancer initiation and progression and boasts many attractive features for both biomarker and therapeutic research. Genetic linkage studies show that many ncRNAs are located in cancer-associated genomic regions that are frequently deleted or amplified in prostate cancer, whereas aberrant ncRNA expression patterns have well-established links with prostate tumor cell proliferation and survival. The dysregulation of pathways controlled by ncRNAs results in a cascade of multicellular events leading to carcinogenesis and tumor progression. The characterization of RNA species, their functions, and their clinical applicability is a major area of biologic and clinical importance. This review summarizes the growing body of evidence, supporting a pivotal role for ncRNAs in the pathogenesis of prostate cancer. We highlight the most promising ncRNA biomarkers for detection and risk stratification and present the state-of-play for RNA-based personalized medicine in treating the “untreatable” prostate tumors. Clin Cancer Res; 20(1); 35–43. ©2013 AACR.

Purpose We investigated the metabolic response of lung cancer to radiotherapy or chemoradiotherapy by 18F-FDG PET and its utility in guiding timely supplementary therapy. Methods Glucose metabolic rate (MRglc) was measured in primary lung cancers during the 3 weeks before, and 10–12 days (S2), 3 months (S3), 6 months (S4), and 12 months (S5) after radiotherapy or chemoradiotherapy. The association between the lowest residual MRglc representing the maximum metabolic response (MRglc-MMR) and tumor control probability (TCP) at 12 months was modeled using logistic regression. Results We accrued 106 patients, of whom 61 completed the serial 18F-FDG PET scans. The median values of MRglc at S2, S3 and S4 determined using a simplified kinetic method (SKM) were, respectively, 0.05, 0.06 and 0.07 μmol/min/g for tumors with local control and 0.12, 0.16 and 0.19 μmol/min/g for tumors with local failure, and the maximum standard uptake values (SUVmax) were 1.16, 1.33 and 1.45 for tumors with local control and 2.74, 2.74 and 4.07 for tumors with local failure (p

Background Ipilimumab, an anti-CTLA4 monoclonal antibody, demonstrated survival benefit in melanoma with immune-related (ir) adverse events (irAEs) managed by the protocol-defined guidelines. This phase 2 study evaluated ipilimumab + paclitaxel (Taxol)/carboplatin in extensive-disease-small-cell lung cancer (ED-SCLC). Design Patients (n = 130) with chemotherapy-naive ED-SCLC were randomized 1: 1: 1 to receive paclitaxel (175 mg/m2)/carboplatin (area under the curve = 6) with either placebo (control) or ipilimumab 10 mg/kg in two alternative regimens, concurrent ipilimumab (ipilimumab + paclitaxel/carboplatin followed by placebo + paclitaxel/carboplatin) or phased ipilimumab (placebo + paclitaxel/carboplatin followed by ipilimumab + paclitaxel/carboplatin). Treatment was administered every 3 weeks for a maximum of 18 weeks (induction), followed by maintenance ipilimumab or placebo every 12 weeks. End points included progression-free survival (PFS), irPFS, best overall response rate (BORR); irBORR, overall survival (OS), and safety. Results Phased ipilimumab, but not concurrent ipilimumab, improved irPFS versus control [HR (hazard ratio) = 0.64; P = 0.03]. No improvement in PFS (HR = 0.93; P = 0.37) or OS (HR = 0.75; P = 0.13) occurred. Phased ipilimumab, concurrent ipilimumab and control, respectively, were associated with median irPFS of 6.4, 5.7 and 5.3 months; median PFS of 5.2, 3.9 and 5.2 months; median OS of 12.9, 9.1 and 9.9 months. Overall rates of grade 3/4 irAEs were 17, 21 and 9% for phased ipilimumab, concurrent ipilimumab and control, respectively. Conclusion These results suggest further investigation of ipilimumab in ED-SCLC.

Life-threatening infectious disease emergencies require immediate, aggressive parenteral administration of antimicrobial agents to ensure high bactericidal concentrations of drug at the site of infection. Usually initial treatment is empiric until culture results and antimicrobial sensitivities are reported. This approach necessitates the use of broad-spectrum bactericidal agents that will eradicate the presumed infecting organism(s), which potentially could be multidrug resistant. For infections potentially attributable to gram-positive bacteria, vancomycin is commonly used because it will be effective for highly resistant strains such as MRSA and multidrug-resistant S pneumoniae. For gram-negative infections, broad-spectrum β-lactams, such as ceftriaxone, piperacillin-tazobactam, and the carbapenems, are commonly chosen. Excellent alternatives include the fluoroquinolone antibiotics. For nosocomial infections whereby P aeruginosa and other highly resistant organisms may be the cause, antipseudomonal β-lactams such as cefepime, ceftazidime, piperacillin-tazobactam, or doripenem may be used as well as the fluoroquinolone, ciprofloxacin. For anaerobic infections, it is usually necessary to add either metronidazole or clindamycin. Once an infection is under control and the culture and sensitivity results are reported, it is important to switch to the most narrow-spectrum agent possible. Taking this action will decrease the potential for adverse drug effects and the risk of development of antibiotic-induced resistance.

Cocaine-associated toxicity is the result of effects on the cardiovascular and central nervous systems. Since the primary route of cocaine inactivation is enzymatic degradation by butyrylcholinesterase (BChE), we sought to determine if the administration of purified human enzyme would ameliorate the lethal effects of cocaine. While the cardiovascular, autonomic or central nervous systems were unaffected by BChE, the enzyme reduced the adverse effects of cocaine including hypertension, hyperactivity and convulsions. BChE decreased both the brain and blood levels of cocaine and shifted the metabolites towards the production of the inactive product ecgonine methyl ester and away from the physiologically active metabolites, norcocaine and benzoylecgonine. We conclude that BChE would appear to be an ideal antidote in the treatment of cocaine intoxication and has potential therapeutic application.

Sox2 marks dental epithelial stem cells (DESC) in both mammals and reptiles, and in this report we demonstrate several Sox2 transcriptional mechanisms that regulate dental stem cell fate and incisor growth. Conditional Sox2 deletion in the oral and dental epithelium results in severe craniofacial defects, including impaired dental stem cell proliferation, arrested incisor development and abnormal molar development. The murine incisor develops initially but is absorbed independent of apoptosis due to a lack of progenitor cell proliferation and differentiation. Tamoxifen induced inactivation of Sox2 demonstrates the requirement of Sox2 for maintenance of the DESCs in adult mice. Conditional overexpression of Lef-1 in mice increases DESC proliferation and creates a new labial cervical loop stem cell compartment, which produces rapidly growing long tusk-like incisors, and Lef-1 epithelial overexpression partially rescues the tooth arrest in Sox2 conditional knockout mice. Mechanistically, Pitx2 and Sox2 interact physically and regulate Lef-1, Pitx2 and Sox2 expression during development. Thus, we have uncovered a Pitx2:Sox2:Lef-1 transcriptional mechanism that regulates DESC homeostasis and dental development.

Aberrant activation of Wnts is common in human cancers, including prostate. Hypermethylation associated transcriptional silencing of Wnt antagonist genes SFRPs (Secreted Frizzled-Related Proteins) is a frequent oncogenic event. The significance of this is not known in prostate cancer. The objectives of our study were to (i) profile Wnt signaling related gene expression and (ii) investigate methylation of Wnt antagonist genes in prostate cancer. Using TaqMan Low Density Arrays, we identified 15 Wnt signaling related genes with significantly altered expression in prostate cancer; the majority of which were upregulated in tumors. Notably, histologically benign tissue from men with prostate cancer appeared more similar to tumor (r = 0.76) than to benign prostatic hyperplasia (BPH; r = 0.57, p < 0.001). Overall, the expression profile was highly similar between tumors of high (≥ 7) and low (≤ 6) Gleason scores. Pharmacological demethylation of PC-3 cells with 5-Aza-CdR reactivated 39 genes (≥ 2-fold); 40% of which inhibit Wnt signaling. Methylation frequencies in prostate cancer were 10% (2/20) (SFRP1), 64.86% (48/74) (SFRP2), 0% (0/20) (SFRP4) and 60% (12/20) (SFRP5). SFRP2 methylation was detected at significantly lower frequencies in high-grade prostatic intraepithelial neoplasia (HGPIN; 30%, (6/20), p = 0.0096), tumor adjacent benign areas (8.82%, (7/69), p < 0.0001) and BPH (11.43% (4/35), p < 0.0001). The quantitative level of SFRP2 methylation (normalized index of methylation) was also significantly higher in tumors (116) than in the other samples (HGPIN = 7.45, HB = 0.47, and BPH = 0.12). We show that SFRP2 hypermethylation is a common event in prostate cancer. SFRP2 methylation in combination with other epigenetic markers may be a useful biomarker of prostate cancer.

Purpose Ipilimumab, which is an anti–cytotoxic T-cell lymphocyte-4 monoclonal antibody, showed a survival benefit in melanoma with adverse events (AEs) managed by protocol-defined guidelines. A phase II study in lung cancer assessed the activity of ipilimumab plus paclitaxel and carboplatin. Patients and Methods Patients (N = 204) with chemotherapy-naive non–small-cell lung cancer (NSCLC) were randomly assigned 1:1:1 to receive paclitaxel (175 mg/m2) and carboplatin (area under the curve, 6) with either placebo (control) or ipilimumab in one of the following two regimens: concurrent ipilimumab (four doses of ipilimumab plus paclitaxel and carboplatin followed by two doses of placebo plus paclitaxel and carboplatin) or phased ipilimumab (two doses of placebo plus paclitaxel and carboplatin followed by four doses of ipilimumab plus paclitaxel and carboplatin).Treatment was administered intravenously every 3 weeks for ≤ 18 weeks (induction). Eligible patients continued ipilimumab or placebo every 12 weeks as maintenance therapy. Response was assessed by using immune-related response criteria and modified WHO criteria. The primary end point was immune-related progression-free survival (irPFS). Other end points were progression-free survival (PFS), best overall response rate (BORR), immune-related BORR (irBORR), overall survival (OS), and safety. Results The study met its primary end point of improved irPFS for phased ipilimumab versus the control (hazard ratio [HR], 0.72; P = .05), but not for concurrent ipilimumab (HR, 0.81; P = .13). Phased ipilimumab also improved PFS according to modified WHO criteria (HR, 0.69; P = .02). Phased ipilimumab, concurrent ipilimumab, and control treatments were associated with a median irPFS of 5.7, 5.5, and 4.6 months, respectively, a median PFS of 5.1, 4.1, and 4.2 months, respectively, an irBORR of 32%, 21% and 18%, respectively, a BORR of 32%, 21% and 14%, respectively, and a median OS of 12.2, 9.7, and 8.3 months. Overall rates of grade 3 and 4 immune-related AEs were 15%, 20%, and 6% for phased ipilimumab, concurrent ipilimumab, and the control, respectively. Two patients (concurrent, one patient; control, one patient) died from treatment-related toxicity. Conclusion Phased ipilimumab plus paclitaxel and carboplatin improved irPFS and PFS, which supports additional investigation of ipilimumab in NSCLC.

Trindenyl trimolybdenum and tritungsten complexes, syn,syn,anti-Td[M(CO)3R]3 (Td = dihydro-1H-trindene trianion; M = Mo, W; R = methyl, benzyl, p-xylyl), have been prepared where two M(CO)3R groups...

Introduction Although patients with non-small cell lung cancer (NSCLC) whose tumors harbor epidermal growth factor receptor (EGFR) activating mutations commonly experience significant regressions when treated with erlotinib or gefitinib, they uniformly develop resistance to these agents. The secondary EGFR T790M mutation is found in 50% of patients with acquired resistance. Herein, we studied XL647, an oral small molecule inhibitor of multiple receptor tyrosine kinases, including EGFR, VEGFR2, HER2, and EphB4, in NSCLC patients known or suspected of having tumors harboring T790M. Methods Eligible patients included those with relapsed or recurrent advanced NSCLC who progressed after ≥12 weeks of stable disease or response to erlotinib or gefitinib and/or those patients with a documented EGFR T790M. XL647 300 mg was administered once daily. The primary end point was objective response rate. Pretreatment plasma samples were collected for mutation testing of circulating tumor DNA. Results Forty-one patients were enrolled; 33 were evaluable for efficacy. One partial response was observed (response rate 3% and 90% confidence interval, 0% to 14%). Of patients whose tumors harbored T790M, 67% (8/12) had progression of disease as best response compared with 14% (3/21) of those without this mutation. Plasma samples from 40 patients were available for mutation testing, 14 (35%) of which were found to have EGFR mutations. Conclusions The 3% response rate observed did not meet the prespecified threshold to recommend further study of XL647 in patients who develop acquired resistance to erlotinib or gefitinib. Patients with T790M had a significantly worse progression-free survival.

Wnt signaling is required for lineage commitment of glandular stem cells (SCs) during tracheal submucosal gland (SMG) morphogenesis from the surface airway epithelium (SAE). Whether similar Wnt-dependent processes coordinate SC expansion in adult SMGs following airway injury remains unknown. We found that two Wnt-reporters in mice (BAT-gal and TCF/Lef:H2B-GFP) are coexpressed in actively cycling SCs of primordial glandular placodes and in a small subset of adult SMG progenitor cells that enter the cell cycle 24 hours following airway injury. At homeostasis, these Wnt reporters showed nonoverlapping cellular patterns of expression in the SAE and SMGs. Following tracheal injury, proliferation was accompanied by dynamic changes in Wnt-reporter activity and the analysis of 56 Wnt-related signaling genes revealed unique temporal changes in expression within proximal (gland-containing) and distal (gland-free) portions of the trachea. Wnt stimulation in vivo and in vitro promoted epithelial proliferation in both SMGs and the SAE. Interestingly, slowly cycling nucleotide label-retaining cells (LRCs) of SMGs were spatially positioned near clusters of BAT-gal positive serous tubules. Isolation and culture of tet-inducible H2B-GFP LRCs demonstrated that SMG LRCs were more proliferative than SAE LRCs and culture expanded SMG-derived progenitor cells outcompeted SAE-derived progenitors in regeneration of tracheal xenograft epithelium using a clonal analysis competition assay. SMG-derived progenitors were also multipotent for cell types in the SAE and formed gland-like structures in xenografts. These studies demonstrate the importance of Wnt signals in modulating SC phenotypes within tracheal niches and provide new insight into phenotypic differences of SMG and SAE SCs.

Background: Personalizing non-small-cell lung cancer (NSCLC) therapy toward oncogene addicted pathway inhibition is effective. Hence, the ability to determine a more comprehensive genotype for each case is becoming essential to optimal cancer care. Methods: We developed a multiplexed PCR-based assay (SNaPshot) to simultaneously identify >50 mutations in several key NSCLC genes. SNaPshot and FISH for ALK translocations were integrated into routine practice as Clinical Laboratory Improvement Amendments-certified tests. Here, we present analyses of the first 589 patients referred for genotyping. Results: Pathologic prescreening identified 552 (95%) tumors with sufficient tissue for SNaPshot; 51% had ≥1 mutation identified, most commonly in KRAS (24%), EGFR (13%), PIK3CA (4%) and translocations involving ALK (5%). Unanticipated mutations were observed at lower frequencies in IDH and β-catenin. We observed several associations between genotypes and clinical characteristics, including increased PIK3CA mutations in squamous cell cancers. Genotyping distinguished multiple primary cancers from metastatic disease and steered 78 (22%) of the 353 patients with advanced disease toward a genotype-directed targeted therapy. Conclusions: Broad genotyping can be efficiently incorporated into an NSCLC clinic and has great utility in influencing treatment decisions and directing patients toward relevant clinical trials. As more targeted therapies are developed, such multiplexed molecular testing will become a standard part of practice.

In cystic fibrosis (CF), a lack of functional CF transmembrane conductance regulator (CFTR) chloride channels causes defective secretion by submucosal glands (SMGs), leading to persistent bacterial infection that damages airways and necessitates tissue repair. SMGs are also important niches for slow-cycling progenitor cells (SCPCs) in the proximal airways, which may be involved in disease-related airway repair. Here, we report that calcitonin gene–related peptide (CGRP) activates CFTR-dependent SMG secretions and that this signaling pathway is hyperactivated in CF human, pig, ferret, and mouse SMGs. Since CGRP-expressing neuroendocrine cells reside in bronchiolar SCPC niches, we hypothesized that the glandular SCPC niche may be dysfunctional in CF. Consistent with this hypothesis, CFTR-deficient mice failed to maintain glandular SCPCs following airway injury. In wild-type mice, CGRP levels increased following airway injury and functioned as an injury-induced mitogen that stimulated SMG progenitor cell proliferation in vivo and altered the proliferative potential of airway progenitors in vitro. Components of the receptor for CGRP (RAMP1 and CLR) were expressed in a very small subset of SCPCs, suggesting that CGRP indirectly stimulates SCPC proliferation in a non-cell-autonomous manner. These findings demonstrate that CGRP-dependent pathways for CFTR activation are abnormally upregulated in CF SMGs and that this sustained mitogenic signal alters properties of the SMG progenitor cell niche in CF airways. This discovery may have important implications for injury/repair mechanisms in the CF airway.

Purpose Understanding of prognosis among terminally ill patients impacts medical decision making. The aims of this study were to explore perceptions of prognosis and goals of therapy in patients with metastatic non–small-cell lung cancer (NSCLC) and to examine the effect of early palliative care on these views over time. Patients and Methods Patients with newly diagnosed metastatic NSCLC were randomly assigned to receive either early palliative care integrated with standard oncology care or standard oncology care alone. Participants completed baseline and longitudinal assessments of their perceptions of prognosis and the goals of cancer therapy over a 6-month period. Results We enrolled 151 participants on the study. Despite having terminal cancer, one third of patients (46 of 145 patients) reported that their cancer was curable at baseline, and a majority (86 of 124 patients) endorsed getting rid of all of the cancer as a goal of therapy. Baseline perceptions of prognosis (ie, curability) and goals of therapy did not differ significantly between study arms. A greater percentage of patients assigned to early palliative care retained or developed an accurate assessment of their prognosis over time (82.5% v 59.6%; P = .02) compared with those receiving standard care. Patients receiving early palliative care who reported an accurate perception of their prognosis were less likely to receive intravenous chemotherapy near the end of life (9.4% v 50%; P = .02). Conclusion Many patients with newly diagnosed metastatic NSCLC hold inaccurate perceptions of their prognoses. Early palliative care significantly improves patient understanding of prognosis over time, which may impact decision making about care near the end of life.

Introduction: Therapeutic agents directed against the epidermal growth factor receptor (EGFR) signaling pathway have been effective in the treatment of non-small cell lung cancer (NSCLC). Cetuximab is a monoclonal antibody against the EGFR receptor with antitumor activity in NSCLC. This study evaluated the efficacy of cetuximab monotherapy after prior treatment with an oral EGFR tyrosine kinase inhibitor (TKI). Methods: Eligible patients had stage IIIB, IV, or recurrent NSCLC with progression on the oral EGFR TKIs gefitinib or erlotinib. Cetuximab was administered intravenously at 400 mg/m2 on day 1 and then 250 mg/m2 weekly until disease progression or unacceptable toxicity. The primary end point was response rate. Results: Eighteen patients were enrolled. Patients were heavily pretreated with chemotherapy and TKIs (average number of treatments = 4.2). The response rate was 0/18 (0%), and 28% of patients had confirmed stable disease. Median progression-free survival was 1.8 months (95% confidence interval, 1.6–5.4 months), and median overall survival was 7.5 months (95% confidence interval, 2.2–19 months). Three patients harbored activating EGFR mutations, and one of them had stable disease for nearly 6 months on cetuximab. Common toxicities were mild and included fatigue, skin rash, and nausea/vomiting. Two patients developed interstitial lung disease, life threatening in one case. Conclusions: Cetuximab monotherapy administered after prior EGFR TKI treatment in patients with advanced NSCLC does not yield clinical responses.

Background Patients with metastatic non–small-cell lung cancer have a substantial symptom burden and may receive aggressive care at the end of life. We examined the effect of introducing palliative care early after diagnosis on patient-reported outcomes and end-of-life care among ambulatory patients with newly diagnosed disease. Methods We randomly assigned patients with newly diagnosed metastatic non–small-cell lung cancer to receive either early palliative care integrated with standard oncologic care or standard oncologic care alone. Quality of life and mood were assessed at baseline and at 12 weeks with the use of the Functional Assessment of Cancer Therapy–Lung (FACT-L) scale and the Hospital Anxiety and Depression Scale, respectively. The primary outcome was the change in the quality of life at 12 weeks. Data on end-of-life care were collected from electronic medical records. Results Of the 151 patients who underwent randomization, 27 died by 12 weeks and 107 (86% of the remaining patients) completed assessments. Patients assigned to early palliative care had a better quality of life than did patients assigned to standard care (mean score on the FACT-L scale [in which scores range from 0 to 136, with higher scores indicating better quality of life], 98.0 vs. 91.5; P = 0.03). In addition, fewer patients in the palliative care group than in the standard care group had depressive symptoms (16% vs. 38%, P = 0.01). Despite the fact that fewer patients in the early palliative care group than in the standard care group received aggressive end-of-life care (33% vs. 54%, P = 0.05), median survival was longer among patients receiving early palliative care (11.6 months vs. 8.9 months, P = 0.02). Conclusions Among patients with metastatic non–small-cell lung cancer, early palliative care led to significant improvements in both quality of life and mood. As compared with patients receiving standard care, patients receiving early palliative care had less aggressive care at the end of life but longer survival. (Funded by an American Society of Clinical Oncology Career Development Award and philanthropic gifts; ClinicalTrials.gov number, NCT01038271.)

Shortly before his death in 1995, Kenneth B. Schwartz, a cancer patient at Massachusetts General Hospital, founded the Kenneth B. Schwartz Center®, a nonprofit organization dedicated to supporting and advancing compassionate health care. The Center sponsors Schwartz Rounds®, a multidisciplinary forum in which doctors, nurses, chaplains, social workers, and other staff reflect on important psychosocial issues that arise in caring for patients. Attendees participate in an interactive discussion about issues anchored in a case presentation and share their experiences, thoughts, and feelings. The patient narratives may center on wonderful events and transcendent experiences or tragic stories, during which staff can only bear witness to the suffering. The Rounds focus on caregivers' experiences, and encourage staff to share insights, own their vulnerabilities, and support each other. The primary objective is to foster healing relationships and provide support to professional caregivers, enhance communication among caregivers, and improve the connection between patients and caregivers. Currently, >50,000 clinicians attend monthly Schwartz Rounds at 195 sites in 31 states, numbers that are rapidly growing. In this article we explore the reasons that contribute to the success of this model of multidisciplinary reflection.