Risk factors and health behaviors associated with loneliness among cancer survivors during the COVID-19 pandemic.

Loneliness may exacerbate poor health outcomes particularly among cancer survivors during the COVID-19 pandemic. Little is known about the risk factors of loneliness among cancer survivors. We evaluated the risk factors of loneliness in the context of COVID-19 pandemic-related prevention behaviors and lifestyle/psychosocial factors among cancer survivors. Cancer survivors (n = 1471) seen at Huntsman Cancer Institute completed a survey between August-September 2020 evaluating health behaviors, medical care, and psychosocial factors including loneliness during COVID-19 pandemic. Participants were classified into two groups: 'lonely' (sometimes, usually, or always felt lonely in past month) and 'non-lonely' (never or rarely felt lonely in past month). 33% of cancer survivors reported feeling lonely in the past month. Multivariable logistic regression showed female sex, not living with a spouse/partner, poor health status, COVID-19 pandemic-associated lifestyle factors including increased alcohol consumption and marijuana/CBD oil use, and psychosocial stressors such as disruptions in daily life, less social interaction, and higher perceived stress and financial stress were associated with feeling lonely as compared to being non-lonely (all p < 0.05). A significant proportion of participants reported loneliness, which is a serious health risk among vulnerable populations, particularly cancer survivors. Modifiable risk factors such as unhealthy lifestyle behaviors and psychosocial stress were associated with loneliness. These results highlight the need to screen for unhealthy lifestyle factors and psychosocial stressors to identify cancer survivors at increased risk of loneliness and to develop effective management strategies.

Associations of combined physical activity and body mass index groups with colorectal cancer survival outcomes.

BACKGROUND: Physical activity and BMI have been individually associated with cancer survivorship but have not yet been studied in combinations in colorectal cancer patients. Here, we investigate individual and combined associations of physical activity and BMI groups with colorectal cancer survival outcomes. METHODS: Self-reported physical activity levels (MET hrs/wk) were assessed using an adapted version of the International Physical Activity Questionnaire (IPAQ) at baseline in 931 patients with stage I-III colorectal cancer and classified into 'highly active' and'not-highly active'(≥ / < 18 MET hrs/wk). BMI (kg/m2) was categorized into 'normal weight', 'overweight', and 'obese'. Patients were further classified into combined physical activity and BMI groups. Cox-proportional hazard models with Firth correction were computed to assess associations [hazard ratio (HR), 95% profile HR likelihood confidence interval (95% CI) between individual and combined physical activity and BMI groups with overall and disease-free survival in colorectal cancer patients. RESULTS: 'Not-highly active' compared to 'highly active' and 'overweight'/ 'obese' compared to 'normal weight' patients had a 40-50% increased risk of death or recurrence (HR: 1.41 (95% CI: 0.99-2.06), p = 0.03; HR: 1.49 (95% CI: 1.02-2.21) and HR: 1.51 (95% CI: 1.02-2.26), p = 0.04, respectively). 'Not-highly active' patients had worse disease-free survival outcomes, regardless of their BMI, compared to 'highly active/normal weight' patients. 'Not-highly active/obese' patients had a 3.66 times increased risk of death or recurrence compared to 'highly active/normal weight' patients (HR: 4.66 (95% CI: 1.75-9.10), p = 0.002). Lower activity thresholds yielded smaller effect sizes. CONCLUSION: Physical activity and BMI were individually associated with disease-free survival among colorectal cancer patients. Physical activity seems to improve survival outcomes in patients regardless of their BMI.

Ampullary Adenocarcinoma, Version 1.2023, NCCN Clinical Practice Guidelines in Oncology.

Ampullary cancers refer to tumors originating from the ampulla of Vater (the ampulla, the intraduodenal portion of the bile duct, and the intraduodenal portion of the pancreatic duct), while periampullary cancers may arise from locations encompassing the head of the pancreas, distal bile duct, duodenum, or ampulla of Vater. Ampullary cancers are rare gastrointestinal malignancies, and prognosis varies greatly based on factors such as patient age, TNM classification, differentiation grade, and treatment modality received. Systemic therapy is used in all stages of ampullary cancer, including neoadjuvant therapy, adjuvant therapy, and first-line or subsequent-line therapy for locally advanced, metastatic, and recurrent disease. Radiation therapy may be used in localized ampullary cancer, sometimes in combination with chemotherapy, but there is no high-level evidence to support its utility. Select tumors may be treated surgically. This article describes NCCN recommendations regarding management of ampullary adenocarcinoma.

Piperacillin-Tazobactam Compared With Cefoxitin as Antimicrobial Prophylaxis for Pancreatoduodenectomy: A Randomized Clinical Trial.

Importance: Despite improvements in perioperative mortality, the incidence of postoperative surgical site infection (SSI) remains high after pancreatoduodenectomy. The effect of broad-spectrum antimicrobial surgical prophylaxis in reducing SSI is poorly understood. Objective: To define the effect of broad-spectrum perioperative antimicrobial prophylaxis on postoperative SSI incidence compared with standard care antibiotics. Design, Setting, and Participants: Pragmatic, open-label, multicenter, randomized phase 3 clinical trial at 26 hospitals across the US and Canada. Participants were enrolled between November 2017 and August 2021, with follow-up through December 2021. Adults undergoing open pancreatoduodenectomy for any indication were eligible. Individuals were excluded if they had allergies to study medications, active infections, chronic steroid use, significant kidney dysfunction, or were pregnant or breastfeeding. Participants were block randomized in a 1:1 ratio and stratified by the presence of a preoperative biliary stent. Participants, investigators, and statisticians analyzing trial data were unblinded to treatment assignment. Intervention: The intervention group received piperacillin-tazobactam (3.375 or 4 g intravenously) as perioperative antimicrobial prophylaxis, while the control group received cefoxitin (2 g intravenously; standard care). Main Outcomes and Measures: The primary outcome was development of postoperative SSI within 30 days. Secondary end points included 30-day mortality, development of clinically relevant postoperative pancreatic fistula, and sepsis. All data were collected as part of the American College of Surgeons National Surgical Quality Improvement Program. Results: The trial was terminated at an interim analysis on the basis of a predefined stopping rule. Of 778 participants (378 in the piperacillin-tazobactam group [median age, 66.8 y; 233 {61.6%} men] and 400 in the cefoxitin group [median age, 68.0 y; 223 {55.8%} men]), the percentage with SSI at 30 days was lower in the perioperative piperacillin-tazobactam vs cefoxitin group (19.8% vs 32.8%; absolute difference, -13.0% [95% CI, -19.1% to -6.9%]; P < .001). Participants treated with piperacillin-tazobactam, vs cefoxitin, had lower rates of postoperative sepsis (4.2% vs 7.5%; difference, -3.3% [95% CI, -6.6% to 0.0%]; P = .02) and clinically relevant postoperative pancreatic fistula (12.7% vs 19.0%; difference, -6.3% [95% CI, -11.4% to -1.2%]; P = .03). Mortality rates at 30 days were 1.3% (5/378) among participants treated with piperacillin-tazobactam and 2.5% (10/400) among those receiving cefoxitin (difference, -1.2% [95% CI, -3.1% to 0.7%]; P = .32). Conclusions and Relevance: In participants undergoing open pancreatoduodenectomy, use of piperacillin-tazobactam as perioperative prophylaxis reduced postoperative SSI, pancreatic fistula, and multiple downstream sequelae of SSI. The findings support the use of piperacillin-tazobactam as standard care for open pancreatoduodenectomy. Trial Registration: ClinicalTrials.gov Identifier: NCT03269994.

Hospital Costs Following Surgical Complications: A Value-driven Outcomes Analysis of Cost Savings Due to Complication Prevention.

OBJECTIVE: Surgical complications have substantial impact on healthcare costs. We propose an analysis of the financial impact of postoperative complications. SUMMARY OF BACKGROUND DATA: Both complications and preoperative patient risk have been shown to increase costs following surgery. The extent of cost increase due to specific complications has not been well described. METHODS: A single institution's American College of Surgeons National Surgical Quality Improvement Program data was queried from 2012 to 2018 and merged with institutional cost data for each encounter. A mixed effects multivariable generalized linear model was used to estimate the mean relative increase in hospital cost due to each complication, adjusting for patient and procedure-level fixed effects clustered by procedure. Potential savings were calculated based on projected decreases in complication rates and theoretical hospital volume. RESULTS: There were 11,897 patients linked between the 2 databases. The rate of any American College of Surgeons National Surgical Quality Improvement Program complication was 11.7%. The occurrence of any complication resulted in a 1.5-fold mean increase in direct hospital cost [95% confidence interval (CI) 1.49-1.58]. The top 6 most costly complications were postoperative septic shock (4.0-fold, 95% CI 3.58-4.43) renal insufficiency/failure (3.3-fold, 95% CI 2.91-3.65), any respiratory complication (3.1-fold, 95% CI 2.94-3.36), cardiac arrest (3.0-fold, 95% CI 2.64-3.46), myocardial infarction (2.9-fold, 95% CI 2.43-3.42) and mortality within 30 days (2.2-fold, 95% CI 2.01-2.48). Length of stay (6.5 versus 3.2 days, P < 0.01), readmission rate (29.1% vs 3.1%, P < 0.01), and discharge destination outside of home (20.5% vs 2.7%, P < 0.01) were significantly higher in the population who experienced complications. CONCLUSIONS: Decreasing complication rates through preoperative optimization will improve patient outcomes and lead to substantial cost savings.

Factors associated with changes in exercise behaviors during the COVID-19 pandemic.

PURPOSE: There is limited information on how the COVID-19 pandemic has changed health behaviors among cancer patients. We examined changes in exercise behaviors since the pandemic and identified characteristics associated with these changes among cancer patients. METHODS: Cancer patients (n = 1,210) completed a survey from August to September 2020 to assess COVID-19 pandemic-related changes in health behaviors and psychosocial factors. Patients were categorized into three groups: exercising less, exercising did not change, and exercising more. Patient characteristics were compared by exercise groups. RESULTS: One-third of the patients reported a decreased amount of regular exercise, while 10% reported exercising more during the pandemic. Patients who exercised less were more likely to be unemployed/retired and have poor health status and psychosocial stressors such as disruptions in daily life while less likely to be former smokers (all p < 0.05). In contrast, patients who exercised more were younger, had stage IV diagnosis, and also reported disruptions in daily life (all p < 0.05). Patients who were living in rural areas were also more likely not to experience changes in exercise habits (all p < 0.05), although rural-urban status was not identified as a strong predictor. CONCLUSION: A significant proportion of cancer patients experienced changes in exercise habits, especially exercising less, during the first 6 months of the COVID-19 pandemic. Age, employment status, tumor stage, health status, smoking status, and psychosocial factors were associated with changes in exercise behaviors. Our results highlight the importance of promoting physical activity guidelines for cancer survivorship during the COVID-19 pandemic and may help improve the identification of cancer patients susceptible to exercising less.

Decompositions of the Contribution of Treatment Disparities to Survival Disparities in Stage I-II Pancreatic Adenocarcinoma.

BACKGROUND: Higher socioeconomic status (SES) and non-Hispanic White (NHW) race/ethnicity are associated with higher treatment rates and longer overall survival (OS) among US patients with stage I-II pancreatic ductal adenocarcinoma. The proportion of OS disparities mediated through treatment disparities (PM) and the proportion predicted to be eliminated (PE) if treatment disparities were eliminated are unknown. METHODS: We analyzed 2007-2015 data from the Surveillance, Epidemiology, and End Results (SEER) census tract-level database and the National Cancer Database (NCDB) using causal mediation analysis methods to understand the extent to which treatment disparities mediate OS disparities. In the first set of decompositions, race/ethnicity was controlled for as a covariate proximal to SES, and lower SES strata were compared with the highest SES stratum. In the second set, an intersectional perspective was taken and each SES-race/ethnicity combination was compared with highest SES-NHW patients, who had the highest treatment rates and longest OS. RESULTS: The SEER and NCDB cohorts contained 16,921 patients and 44,638 patients, respectively. When race/ethnicity was controlled for, PMs ranged from 43 to 48% and PEs ranged from 46 to 50% for various lower SES strata. When separately comparing each SES-race/ethnicity combination with the highest SES-NHW patients, results were similar for lower SES-NHW patients but differed markedly for non-Hispanic Black and Hispanic patients, for whom PMs ranged from 60 to 80% and PEs ranged from 55 to 75% for most lower SES strata. CONCLUSIONS: These results suggest that efforts to reduce treatment disparities are worthwhile, particularly for NHB and Hispanic patients, and simultaneously point to the importance of non-treatment-related causal pathways.

Refusal of Local Therapy in Esophageal Cancer and Impact on Overall Survival.

OBJECTIVE: The aim of this study was to understand factors associated with refusal of local therapy in esophageal cancer and compare the overall survival (OS) of patients who refuse therapies with those who undergo recommended treatment. METHODS: National Cancer Database data for patients with non-metastatic esophageal cancer from 2006 to 2013 were pooled. T1N0M0 tumors were excluded. Pearson's Chi-square test and multivariate logistic regression analyses were used to assess demographic, clinical, and treatment factors. After propensity-score matching with inverse probability of treatment weighting, OS was compared between patients who refused therapies and those who underwent recommended therapy, using Kaplan-Meier analyses and doubly robust estimation with multivariate Cox proportional hazards modeling. RESULTS: In total, 37,618 patients were recommended radiation therapy (RT) and/or esophagectomy; we found 1403 (3.7%) refused local therapies. Specifically, 890 of 18,942 (4.6%) patients refused surgery and 667 of 31,937 (2.1%) refused RT. Older patients, females, those with unknown lymphovascular space invasion, and those uninsured or on Medicare were more likely to refuse. Those with squamous cell carcinoma, N1 disease, higher incomes, living farther from care, and those who received chemotherapy were less likely to refuse. Five-year OS was decreased in patients who refused (18.1% vs. 27.6%). The survival decrement was present in adenocarcinoma but not squamous cell carcinoma. In patients who received surgery or ≥ 50.4 Gy RT, there was no OS decrement to refusing the other therapy. CONCLUSIONS: We identified characteristics that correlate with refusal of local therapy. Refusal of therapy was associated with decreased OS. Patients who received either surgery or ≥ 50.4 Gy RT had no survival decrement from refusing the opposite modality.

Pancreatic Adenocarcinoma, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology.

Pancreatic cancer is the fourth leading cause of cancer-related death among men and women in the United States. A major challenge in treatment remains patients' advanced disease at diagnosis. The NCCN Guidelines for Pancreatic Adenocarcinoma provides recommendations for the diagnosis, evaluation, treatment, and follow-up for patients with pancreatic cancer. Although survival rates remain relatively unchanged, newer modalities of treatment, including targeted therapies, provide hope for improving patient outcomes. Sections of the manuscript have been updated to be concordant with the most recent update to the guidelines. This manuscript focuses on the available systemic therapy approaches, specifically the treatment options for locally advanced and metastatic disease.

County-level Variation in Use of Surgery and Cancer-specific Survival for Stage I-II Pancreatic Adenocarcinoma.

OBJECTIVE: The aim of the study was to describe county-level variation in use of surgery for stage I-II pancreatic ductal adenocarcinoma (PDAC) and the association between county surgery rates and cancer-specific survival (CSS). BACKGROUND: The degree of small geographic area variation in use of surgery for stage I-II PDAC and the association between area surgery rates and CSS remain incompletely defined. METHODS: This is a retrospective cohort study of patients aged 18 to 80 years in the 2007 to 2015 Surveillance, Epidemiology, and End Results database with stage I-II PDAC without contraindications to surgery or refusal. Multilevel models were used to characterize county-level variation in use of surgery and CSS. County-specific risk- and reliability-adjusted surgery rates and CSS rates were calculated. RESULTS: Of 18,100 patients living in 581 counties, 10,944 (60.5%) underwent surgery. Adjusted county-specific surgery rates varied 1.5-fold from 49.9% to 74.6%. Median CSS increased in a graded fashion from 13 months [interquartile range (IQR) 13-14] in counties with surgery rates of 49.9% to 56.9% to 18 months (IQR 17-19) in counties with surgery rates of 68.0% to 74.6%. Results were similar in multivariable analyses. Adjusted county 18-month CSS rates varied 1.6-fold from 32.7% to 53.7%. Adjusted county surgery and 18-month CSS rates were correlated (r = 0.54; P < 0.001) and county surgery rates explained approximately half of county-level variation in CSS. Only 18 (3.1%) counties had adjusted surgery rates of 68.0% to 74.6%, which was associated with the longest CSS. CONCLUSIONS: County-specific rates of surgery varied substantially, and patients living in areas with higher surgery rates lived longer. These data suggest that increasing use of surgery in stage I-II PDAC could lead to improvements in survival.

Size and Importance of Socioeconomic Status-Based Disparities in Use of Surgery in Nonadvanced Stage Gastrointestinal Cancers.

BACKGROUND: The size and importance of socioeconomic status (SES)-based disparities in use of surgery for non-advanced stage gastrointestinal (GI) cancers have not been quantified. METHODS: The exposure in this study of patients age 18-80 with one of nine non-advanced stage GI cancers in the 2007-2015 SEER database was a census tract-level SES composite. Multivariable models assessed associations of SES with use of surgery. Causal mediation analysis was used to estimate the proportion of survival disparities in SES quintiles 1 versus 5 that were mediated by disparities in use of surgery. RESULTS: Lowest SES quintile patients underwent surgery at significantly lower rates than highest quintile patients in each cancer. SES-based disparities in use of surgery were large and graded in esophagus adenocarcinoma, intrahepatic and extrahepatic cholangiocarcinoma, and pancreatic adenocarcinoma. Smaller but clinically relevant disparities were present in stomach, ampulla, and small bowel adenocarcinoma, whereas disparities were small in colorectal adenocarcinoma. Five-year all-stage overall survival (OS) was correlated with the size of disparities in use of surgery in SES quintiles 1 versus 5 (r = - 0.87; p = 0.003). Mean OS was significantly longer (range 3.5-8.9 months) in SES quintile 5 versus 1. Approximately one third of SES-based survival disparities in poor prognosis GI cancers were mediated by disparities in use of surgery. The size of disparities in use of surgery in SES quintiles 1 versus 5 was correlated with the proportion mediated (r = 0.98; p < 0.001). CONCLUSIONS: Low SES patients with poor prognosis GI cancers are at substantial risk of undertreatment. Disparities in use of surgery contribute to diminished survival.

Hospital-level Variation in Utilization of Surgery for Clinical Stage I-II Pancreatic Adenocarcinoma.

OBJECTIVE: To (1) evaluate rates of surgery for clinical stage I-II pancreatic ductal adenocarcinoma (PDAC), (2) identify predictors of not undergoing surgery, (3) quantify the degree to which patient- and hospital-level factors explain differences in hospital surgery rates, and (4) evaluate the association between adjusted hospital-specific surgery rates and overall survival (OS) of patients treated at different hospitals. BACKGROUND: Curative-intent surgery for potentially resectable PDAC is underutilized in the United States. METHODS: Retrospective cohort study of patients ≤85 years with clinical stage I-II PDAC in the 2004 to 2014 National Cancer Database. Mixed effects multivariable models were used to characterize hospital-level variation across quintiles of hospital surgery rates. Multivariable Cox proportional hazards models were used to estimate the effect of adjusted hospital surgery rates on OS. RESULTS: Of 58,553 patients without contraindications or refusal of surgery, 63.8% underwent surgery, and the rate decreased from 2299/3528 (65.2%) in 2004 to 4412/7092 (62.2%) in 2014 (P < 0.001). Adjusted hospital rates of surgery varied 6-fold (11.4%-70.9%). Patients treated at hospitals with higher rates of surgery had better unadjusted OS (median OS 10.2, 13.3, 14.2, 16.5, and 18.4 months in quintiles 1-5, respectively, P < 0.001, log-rank). Treatment at hospitals in lower surgery rate quintiles 1-3 was independently associated with mortality [Hazard ratio (HR) 1.10 (1.01, 1.21), HR 1.08 (1.02, 1.15), and HR 1.09 (1.04, 1.14) for quintiles 1-3, respectively, compared with quintile 5] after adjusting for patient factors, hospital type, and hospital volume. CONCLUSIONS: Quality improvement efforts are needed to help hospitals with low rates of surgery ensure that their patients have access to appropriate surgery.

Pancreatic Adenocarcinoma, Version 1.2019.

The NCCN Guidelines for Pancreatic Adenocarcinoma discuss the diagnosis and management of adenocarcinomas of the exocrine pancreas and are intended to assist with clinical decision-making. These NCCN Guidelines Insights discuss important updates to the 2019 version of the guidelines, focusing on postoperative adjuvant treatment of patients with pancreatic cancers.

A novel case of TIF1 gamma autoantibody positive dermatomyositis associated with a non-functional pancreatic neuroendocrine tumor.

Dermatomyositis (DM) is an idiopathic inflammatory myopathy characterized by proximal muscle weakness associated with a distinct cutaneous eruption. The association of DM with malignancy has been extensively described in the literature. Patients with DM that also have transcriptional intermediary factor 1γ (TIF1γ) autoantibodies (anti-p155, anti-p155/140) have higher rates of malignancy when compared to those without the autoantibody. We report the case of a 65-year-old woman with TIF1γautoantibody positive dermatomyositis associated with a non-functional pancreatic neuroendocrine tumor (PNET). Surgical resection of the PNET resulted in significant clinical improvement and a reduction of TIF1γ autoantibody levels in our patient.

Chemoradiation Therapy for Unresected Extrahepatic Cholangiocarcinoma: A Propensity Score-Matched Analysis.

BACKGROUND: Unresected extrahepatic cholangiocarcinoma (uEHCC) remains a deadly disease. Guidelines for uEHCC recommend either chemotherapy alone (CT) or chemoradiotherapy (CRT). This study used the National Cancer Database (NCDB) to compare outcomes for patients treated with CT and those who underwent CRT. METHODS: Patients with initially diagnosed non-metastatic uEHCC from 2004 to 2014 were identified. Using Chi square analysis, patients who underwent CT were compared with those who received CRT. Uni- and multivariate Cox regression analyses were used to compare characteristics related to survival. Propensity score matching and shared frailty analysis were undertaken to correct for baseline differences between the two groups. Additional analyses were performed to compare survival for the minority of patients who underwent surgery and advanced-stage patients. RESULTS: The study identified 2996 patients with uEHCC. Chemoradiation was associated with better survival (median survival [MS], 14.5 months; hazard ratio [HR] 0.84; p < 0.001) than CT alone (MS, 12.6 months). Induction of CT before CRT was associated with a trend toward decreased risk of death compared with concurrent CRT (HR 0.81; p = 0.051). For the patients able to undergo surgery after initial treatment, MS was 24.5 months (HR 0.38; p < 0.001) versus 12.2 months for those who had no surgery. For these patients, CRT also was associated with better survival (MS, 31.2 months; HR 0.66; p = 0.001) than CT (MS, 22.1 months). Positive margins at surgery yielded survival equivalent to that with no surgery. CONCLUSION: Although CRT may be associated with slightly better survival in uEHCC than CT alone, the majority of the benefit was observed for patients able to undergo eventual surgery.

Pancreatic Adenocarcinoma, Version 2.2017, NCCN Clinical Practice Guidelines in Oncology.

Ductal adenocarcinoma and its variants account for most pancreatic malignancies. High-quality multiphase imaging can help to preoperatively distinguish between patients eligible for resection with curative intent and those with unresectable disease. Systemic therapy is used in the neoadjuvant or adjuvant pancreatic cancer setting, as well as in the management of locally advanced unresectable and metastatic disease. Clinical trials are critical for making progress in treatment of pancreatic cancer. The NCCN Guidelines for Pancreatic Adenocarcinoma focus on diagnosis and treatment with systemic therapy, radiation therapy, and surgical resection.

Transepithelial Transport of PAMAM Dendrimers Across Isolated Human Intestinal Tissue.

Poly(amido amine) (PAMAM) dendrimers have shown transepithelial transport across intestinal epithelial barrier in rats and across Caco-2 cell monolayers. Caco-2 models innately lack mucous barriers, and rat isolated intestinal tissue has been shown to overestimate human permeability. This study is the first report of transport of PAMAM dendrimers across isolated human intestinal epithelium. It was observed that FITC labeled G4-NH2 and G3.5-COOH PAMAM dendrimers at 1 mM concentration do not have a statistically higher permeability compared to free FITC controls in isolated human jejunum and colonic tissues. Mannitol permeability was increased at 10 mM concentrations of G3.5-COOH and G4-NH2 dendrimers. Significant histological changes in human colonic and jejunal tissues were observed at G3.5-COOH and G4-NH2 concentrations of 10 mM implying that dose limiting toxicity may occur at similar concentrations in vivo. The permeability through human isolated intestinal tissue in this study was compared to previous rat and Caco-2 permeability data. This study implicates that PAMAM dendrimer oral drug delivery may be feasible, but it may be limited to highly potent drugs.

Lineage tracing reveals the dynamic contribution of Hes1+ cells to the developing and adult pancreas.

Notch signaling regulates numerous developmental processes, often acting either to promote one cell fate over another or else to inhibit differentiation altogether. In the embryonic pancreas, Notch and its target gene Hes1 are thought to inhibit endocrine and exocrine specification. Although differentiated cells appear to downregulate Hes1, it is unknown whether Hes1 expression marks multipotent progenitors, or else lineage-restricted precursors. Moreover, although rare cells of the adult pancreas express Hes1, it is unknown whether these represent a specialized progenitor-like population. To address these issues, we developed a mouse Hes1(CreERT2) knock-in allele to inducibly mark Hes1(+) cells and their descendants. We find that Hes1 expression in the early embryonic pancreas identifies multipotent, Notch-responsive progenitors, differentiation of which is blocked by activated Notch. In later embryogenesis, Hes1 marks exocrine-restricted progenitors, in which activated Notch promotes ductal differentiation. In the adult pancreas, Hes1 expression persists in rare differentiated cells, particularly terminal duct or centroacinar cells. Although we find that Hes1(+) cells in the resting or injured pancreas do not behave as adult stem cells for insulin-producing beta (ß)-cells, Hes1 expression does identify stem cells throughout the small and large intestine. Together, these studies clarify the roles of Notch and Hes1 in the developing and adult pancreas, and open new avenues to study Notch signaling in this and other tissues.