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2501 citation(s) found for "Ma, C Benjamin".

Histone H3.3 beyond cancer: Germline mutations in Histone 3 Family 3A and 3B cause a previously unidentified neurodegenerative disorder in 46 patients
Bryant, Laura , Li, Dong , Cox, Samuel G., Wilson, Khadija , Janssen, Kevin A. , March, Michael , Sherr, Elliott H. , Fregeau, Brieana, Wierenga, Klaas J. , Wadley, Alexandrea, Mancini, Grazia M.S., Powell‐Hamilton, Nina , Kamp, Jiddeke van de, Grebe, Theresa A., Ross, Alison , Crawford, Heather P., Powis, Zöe , Cho, Megan T. , Willing, Marcia, Schot, Rachel , Afenjar, Alexandra , Lessel, Davor , Wagner, Matias , Klopstock, Thomas , Winkelmann, Juliane , Retterer, Kyle , Schuette, Jane L., Innis, Jeffrey W. , Pizzino, Amy , Lüttgen, Sabine, Denecke, Jonas , Strom, Tim M., Monaghan, Kristin G. , Study, DDD, Yuan, Zuo‐Fei , Dubbs, Holly , Bend, Renee, Lee, Jennifer A. , Lyons, Michael J. , Hoefele, Julia , Günthner, Roman , Keren, Boris , Radtke, Kelly, Sherbini, Omar , Mrokse, Cameron, Helbig, Katherine L. , Odent, Sylvie , Mercier, Sandra , Küry, Sébastien , Redon, Richard , Reinson, Karit , Wojcik, Monica H. , Õunap, Katrin , Ilves, Pilvi , Innes, A. Micheil , Kernohan, Kristin D. , Costain, Gregory , Zackai, Elaine H. , Kitson, Hilary, Study, CAUSES, Martin, Martin G., Martínez-Agosto, Julián A. , Network, Undiagnosed Diseases, Nelson, Stan F., Palmer, Christina G.S. , Papp, Jeanette C. , Parker, Neil H., Wan, Jijun , Yoon, Amanda J., Zheng, Allison, Carli, Diana , Brusco, Alfredo , Tartaglia, Marco , Thomas, Jennifer Muncy, Weiss, Marjan M. , Gotway, Garrett , Stuurman, Kyra E. , Thompson, Michelle L. , Stumpel, Constance T. R. M., Stevens, Servi J.C. , Stegmann, Alexander P.A. , Tveten, Kristian , Vøllo, Arve, Prescott, Trine , Fagerberg, Christina , Laulund, Lone Walentin , Larsen, Martin J. , Byler, Melissa, Lebel, Robert Roger, Dean, Joy, Mercimek‐Andrews, Saadet , Neira, Juanita, Allen, Margot I. Van, Sellars, Elizabeth A. , Louie, Raymond J. , Cathey, Sara , Brokamp, Elly , Héron, Delphine, Snyder, Molly, Simon, Celeste, Cruz, Xavier de la , Padilla, Natàlia , García, Benjamin A. , Håkonarson, Håkon , Bhoj, Elizabeth , Nelson, Stanley F. , Sherr, Elliott , Dean, John , Lessel, Davor , Klopstock, Thomas , Kury, Sebastien , Brusco, Alfredo , McWalter, Kirsty , Stevens, Servi J C , Crump, J Gage , Hakonarson, Hakon , Bhoj, Elizabeth J , Tartaglia, Marco , Li, Dong , Wagner, Matias , Redon, Richard , Õunap, Katrin , de la Cruz, Xavier , Padilla, Natália , March, Michael , Hoefele, Julia , Marchione, Dylan M. , Joiner, Evan F. , Lee, Pearl , Nair, Divya, Kamp, Jiddeke M. van de , Manwaring, Linda P. , Nava, Caroline , Catarino, Claudia B. , Monaghan, Kristin G. , Study, DDD, Reutter, Heiko , Radtke, Kelly , Cogné, Benjamin , Bezieau, Stéphane , Besnard, Thomas , Meyn, M Stephen , Chitayat, David A. , Lehman, Anna , Study, CAUSES, Network, Undiagnosed Diseases, Sinsheimer, Janet S. , Vilain, Eric J. N. , Brimble, Elise , Ferrero, Giovanni Battista , Radio, Francesca Clementina , Barresi, Sabina , Umaña, Luis Alfredo , Hurst, Anna , Vergano, Samantha A. Schrier , Norman, Jennifer, Longo, Nicola , Vanderver, Adeline , Chung, Wendy K.

Science Advances | December 3, 2020 | Volume: 6 | Issue: 49 | Pages: No page available

10.1126/sciadv.abc9207 | PMID 33268356 Get It

Germ line mutations in H3F3A and H3F3B cause a previously unidentified neurodevelopmental syndrome.
Performance of Plasma Adenosine as a Biomarker for Predicting Cardiovascular Risk
Jung, Richard G. , Santo, Pietro Di , Labinaz, Alisha, Gaudet, Chantal, Motazedian, Pouya , Parlow, Simon , Moreland, Robert B. , Marbach, Jeffrey A. , Boland, Paul , Promislow, Steven, Russo, Juan , Chong, Aun‐Yeong , So, Derek , Froeschl, Michael , May, Michel Le, Hibbert, Benjamin , Hibbert, Benjamin , Simard, Trevor , Ramirez, F. Daniel , Joseph, Joanne Emily , Moreland, Robert, May, Michel R. Le

Clinical and Translational Science | December 2, 2020 | Volume: 14 | Issue: 1 | Pages: 354-361

10.1111/cts.12886 | PMID 33264483 Get It

Adenosine boasts promising preclinical and clinical data supporting a vital role in modulating vascular homeostasis. Its widespread use as a diagnostic and therapeutic agent have been limited by its short half‐life and complex biology, though adenosine‐modulators have shown promise in improving vascular healing. Moreover, circulating adenosine has shown promise in predicting cardiovascular (CV) events. We sought to delineate whether circulating plasma adenosine levels predict CV events in patients undergoing invasive assessment for coronary artery disease. Patients undergoing invasive angiography had clinical data prospectively recorded in the Cardiovascular and Percutaneous ClInical TriALs (CAPITAL) revascularization registry and blood samples collected in the CAPITAL Biobank from which adenosine levels were quantified. Tertile‐based analysis was used to assess prediction of major adverse cardiovascular events (MACE; composite of death, myocardial infarction, unplanned revascularization, and cerebrovascular accident). Secondary analyses included MACE subgroups, clinical subgroups and adenosine levels. There were 1,815 patients undergoing angiography who had blood collected with adenosine quantified in 1,323. Of those quantified, 51.0% were revascularized and 7.3% experienced MACE in 12 months of follow‐up. Tertile‐based analysis failed to demonstrate any stratification of MACE rates (log rank, P = 0.83), when comparing low‐to‐middle (hazard ratio (HR) 1.10, 95% confidence interval (CI) 0.68–1.78, P = 0.70) or low‐to‐high adenosine tertiles (HR 0.95, 95% CI 0.56–1.57, P = 0.84). In adjusted analysis, adenosine similarly failed to predict MACE. Finally, adenosine did not predict outcomes in patients with acute coronary syndrome nor in those revascularized or treated medically. Plasma adenosine levels do not predict subsequent CV outcomes or aid in patient risk stratification.
Leveraging Existing and Soon-to-Be-Available Novel Diagnostics for Optimizing Outpatient Antibiotic Stewardship in Patients With Respiratory Tract Infections
Cawcutt, Kelly , Patel, Robin , Gerber, Jeff, Caliendo, Angela M. , Cosgrove, Sara E. , Ashley, Elizabeth Dodds , Garzaro, Piero, Lautenbach, Ebbing , Banerjee, Ritu , Boyd, Sarah E, File, Thomas M. , Livorsi, Daniel J. , May, Larissa, Moehring, Rebekah W. , Nolte, Frederick S. , Szymczak, Julie, Timbrook, Tristan T. , Tsalik, Ephraim L. , Virk, Abinash, Jezek, Amanda, Levy, Jaclyn, Zetts, Rachel M , Hicks, Lauri A. , Wiecek, Joanna , Nettles, Rick, Wittek, James, Murray, Patrick, Ginocchio, Christine C. , Cawcutt, Kelly , Patel, Robin , Gerber, Jeffrey S. , Miller, Melissa B. , Ebell, Mark H. , Graf, Erin H. , Keller, Sara C. , Koo, Sophia , Pinsky, Benjamin A. , Virk, Abinash

Clinical Infectious Diseases | December 2, 2020 | Volume: 72 | Issue: 12 | Pages: e1115-e1121

10.1093/cid/ciaa1815 | PMID 33277647 Get It

Abstract Respiratory tract infections (RTIs) drive many outpatient encounters and, despite being predominantly viral, are associated with high rates of antibiotic prescriptions. With rising antibacterial resistance, optimization of prescribing of antibiotics in outpatients with RTIs is a critical need. Fortunately, this challenge arises at a time of increasing availability of novel RTI diagnostics to help discern which patients have bacterial infections warranting treatment. Effective implementation of antibiotic stewardship is needed, but optimal approaches for ambulatory settings are unknown. Future research needs are reviewed in this summary of a research summit convened by the Infectious Diseases Society of America in the fall of 2019.
Hydroxychloroquine Toxicity
Geisler, Benjamin P. , Kingsley, Thomas C. , Izmirly, Peter , Izmirly, Peter M. , Costedoat-Chalumeau, Nathalie , Roswell, Robert O.

JCR: Journal of Clinical Rheumatology | November 30, 2020 | Volume: 27 | Issue: 8S | Pages: S657-S658

10.1097/rhu.0000000000001647 | PMID 33252397 Get It

The mitral annulus disjunction of mitral valve prolapse: presentation and outcome
Sabbag, A., Antoine, Clémence , Maalouf, Joseph F., Sarano, M.E, Essayagh, Benjamin , Benfari, Giovanni , Michelena, Héctor I. , Sarano, M.E

European Heart Journal | November 26, 2020 | Volume: 41 | Issue: Supplement_2 | Pages: No page available

10.1093/ehjci/ehaa946.1999 Get It

Abstract Background Mitral-annulus-disjunction (MAD), often described in mitral-valve-prolapse (MVP) patients, remains incompletely defined and its clinical outcome consequences are unknown. Objectives To assess MAD prevalence, clinical and echocardiographic characteristics, and independent impact on outcome in patients with isolated-MVP. Methods A cohort of 595 (65±16 years, 278 female) consecutive patients with MVP and comprehensive clinical, rhythmic and Doppler-echocardiographic characterization, was identified. Primary-endpoint was overall-survival, or occurrence of ventricular-arrhythmia. To eliminate clinical differences, we matched MAD-patients 1:1 with no-MAD based on propensity score for overall survival analysis using a greedy 5-to-1 digit-matching algorithm. Results MAD was frequent, present in 186 (31%) of MVP-patients and independently associated to bileaflet-MVP, leaflet-redundancy, younger-age, female-sex, enlarged left-ventricle-endsystolic-diameter and higher left-ventricle-ejection-fraction (all P≤0.04). Outcome primary-endpoint of survival after MVP diagnosis in matched-cohort (10-year 95±1%) was not associated with MAD presence (10-year 93±2% for no-MAD and 97±1% for MAD, P=0.4). Mortality was comparable for MAD (univariate-hazard-ratio 0.64 [0.25–1.65], P=0.4 vs. no-MAD), even adjusted-comprehensively including for MVP-characteristics (adjusted-hazard-ratio 1.17 [0.39–3.50], P=0.8). However, 220 (51%) MVP-patients were diagnosed ventricular-arrhythmia (161 with ventricular-tachycardia only) and long-term, MAD was associated with lower arrhythmia- and ventricular-tachycardia- overall freedom (adjusted-hazard-ratio for MAD 2.35 [1.75–3.15], P<0.0001 vs. no-MAD and 2.71 [1.93–3.82], P<0.0001 respectively). Hence, 10-year freedom of significant ventricular-arrhythmia in overall-cohort was severely reduced with MAD (41±4% vs. 62±3% for no-MAD). Conclusion In this unique MVP cohort, with arrhythmia and MAD comprehensively-characterized, MAD presence was frequent and independently associated to bileaflet-MVP and leaflet-redundancy. Long-term, MAD compared to no-MAD is not independently associated with higher-mortality but to reduced arrhythmia-freedom occurrence. Survival overall and by V arrhythmia Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): Mayo Foundation
International consensus statement on allergy and rhinology: rhinosinusitis 2021
Orlandi, Richard R. , Kingdom, Todd T. , Smith, Timothy L. , Bleier, Benjamin S. , DeConde, Adam S., Luong, Amber , Poetker, David M., Welch, Kevin C. , Wise, Sarah K. , Adappa, Nithin D. , Anselmo‐Lima, Wilma Terezinha , Bachert, Claus , Baroody, Fuad M. , Batra, Pete S., Bernal‐Sprekelsen, Manuel , Bhattacharyya, Neil , Chang, Eugene H., Chowdhury, Naweed I. , Citardi, Martin J. , Cohen, Noah , Conley, David B. , DelGaudio, John M. , Desrosiers, Martin , Douglas, Richard , Eloy, Jean Anderson , Gray, Stacey T. , Gudis, David A. , Hamilos, Daniel L. , Han, Joseph K., Harvey, Richard J. , Hellings, Peter W. , Hopkins, Claire , Hwang, Peter H. , Javer, Amin R. , Kennedy, David W. , Kern, Robert C. , Lee, Heung‐Man , Lee, Jivianne T. , Levy, Joshua M. , Lin, Sandra Y. , Lund, Valerie, McMains, Kevin C. , Metson, Ralph, Naclerio, Robert M. , Oakley, Gretchen M. , Otori, Nobuyoshi , Parikh, Sanjay R., Patel, Zara M. , Peters, Anju T. , Philpott, Carl , Roh, Hwan‐Jung , Rudmik, Luke , Sacks, Raymond , Schlosser, Rodney J. , Sedaghat, Ahmad R. , Senior, Brent A. , Sindwani, Raj , Smith, Kristine A. , Stewart, Michael G. , Suh, Jeffrey D. , Tan, Bruce K. , Drunen, Cornelis M. van , Woodworth, Bradford A. , Wormald, Peter‐John , Wright, Erin D. , Yan, Carol H. , Zhang, Luo , Zhou, Bing , Chang, Michael T. , Bleier, Benjamin , Alt, Jeremiah A , Beswick, Daniel , Eloy, Jean Anderson , Gudis, David A , Holbrook, Eric H , Hopkins, Claire , Javer, Amin R , Jiang, Rong-San , Lal, Devyani , Lee, Heung-Man , Levy, Joshua M , Patel, Zara , Philpott, Carl , Ramakrishnan, Vijay R , Smith, Kristine , Yan, Carol , Zhang, Luo , Schlosser, Rodney J , Harvey, Richard J , Hwang, Peter H , Chang, Michael T , Soler, Zachary M. , Adappa, Nithin D. , Alt, Jeremiah A. , Beswick, Daniel M. , Chandra, Rakesh Kumar , Chang, Eugene H., Chiu, Alexander G. , Cohen, Noam A., Fokkens, Wytske Johanna , Holbrook, Eric H. , Laidlaw, Tanya M. , Lal, Devyani , Lane, Andrew P , Mullol, Joaquim , Passàli, Desiderio , Psaltis, Alkis J. , Ramanathan, Murugappan , Snidvongs, Kornkiat , Turner, Justin H. , Voegels, Richard Louis , Wang, De Yun

International Forum of Allergy & Rhinology | November 25, 2020 | Volume: 11 | Issue: 3 | Pages: 213-739

10.1002/alr.22741 | PMID 33236525 Get It

I. Executive Summary Background The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS.
Changing Medical Education When Change Is Hard: Implementing an Interdepartmental Entrustable Professional Activity
Collins, Eric , Schnapp, Benjamin , Westergaard, Mary , Greenberg, Jacob A. , Jung, Sarah , Rosser, Alexandra A., Minter, Rebecca M., Hamedani, Azita G., Kraut, Aaron , Kraut, Aaron , Stahl, Christopher C.

AEM Education and Training | November 24, 2020 | Volume: 5 | Issue: 3 | Pages: No page available

10.1002/aet2.10561 | PMID 34124509 Get It

AbstractBackgroundEntrustable professional activities (EPAs) are a new tool for assessing learners that represents a significant movement in graduate medical education (GME) toward competency‐based assessment and serves as a bridge between milestones and clinical practice. Whenever a major change is implemented to any system, resistance to change is expected. Many change management models have been proposed to overcome this resistance; a newer model is outlined in the book Switch. The objective was to describe the change management principles used to institute an EPA.MethodsThe model introduced in Switch was used as a framework for implementing a trauma resuscitation EPA in a joint effort between the departments of surgery and emergency medicine (EM) at the University of Wisconsin Hospitals and Clinics. The Department of Emergency Medicine used the principles of change management, completing 295 faculty evaluations of trauma resuscitations compared to the Department of Surgery, whose faculty completed 50 evaluations between the study period of July 2018 through October 2019. A survey completed winter 2019 of EM faculty was used to determine the most important principles toward successful implementation.ResultsTwenty‐seven of 35 (78% response rate) of EM faculty identified key concepts from Switch as being instrumental in the successful implementation. Internal discussion of the implementation approach used by the Department of Surgery identified several limitations that would have been overcome by using these same change management principles.ConclusionWe conclude that the principles of change management provide a useful framework for successfully implementing EPAs into GME.
Average Lumbar Hounsfield Units Predicts Osteoporosis-Related Complications Following Lumbar Spine Fusion
Jeor, Jeffery D. St. , Jackson, Taylor J. , Xiong, Ashley , Freedman, Brett A. , Sebastian, Arjun S. , Currier, Bradford L. , Fogelson, Jeremy L. , Bydon, Mohamad , Elder, Benjamin D. , St Jeor, Jeffery D , Xiong, Ashley E, Nassr, Ahmad

Global Spine Journal | November 23, 2020 | Volume: 12 | Issue: 5 | Pages: 851-857

10.1177/2192568220975365 | PMID 33222537 Get It

Study Design: Retrospective Study. Objective: To compare methods of assessing pre-operative bone density to predict risk for osteoporosis related complications (ORC), defined as proximal junctional kyphosis, pseudarthrosis, accelerated adjacent segment disease, reoperation, compression fracture, and instrument failure following spine fusions. Methods: Chart review of primary posterior thoracolumbar or lumbar fusion patients during a 7 year period. Inclusion criteria: preoperative dual-energy x-ray absorptiometry (DXA) test within 1 year and lumbar CT scan within 6 months prior to surgery with minimum of 1 year follow-up. Exclusion criteria: <18 years at time of index procedure, infection, trauma, malignancy, skeletal dysplasia, neuromuscular disorders, or anterior-posterior procedures. Results: 140 patients were included. The average age was 67.9 years, 83 (59.3%) were female, and 45 (32%) had an ORC. There were no significant differences in patient characteristics between those with and without an ORC. Multilevel fusions were associated with ORCs (46.7% vs 26.3%, p = 0.02). Patients with ORCs had lower DXA t-scores (-1.62 vs -1.10, p = 0.003) and average Hounsfield units (HU) (112.1 vs 148.1, p ≤ 0.001). Multivariable binary logistic regression analysis showed lower average HU (Adj. OR 0.00 595% CI 0.0001-0.1713, p = 0.001) was an independent predictor of an ORC. The odds of an ORC increased by 1.7-fold for every 25 point decrease in average HU. Conclusions: The gold standard for assessing bone mineral density has been DXA t-scores, but the best predictor of ORC remains unclear. While both lower t-scores and average HU were associated with ORC, only HU was an independent predictor of ORC.
Thyroid Cancer Overdiagnosis and Overtreatment: a cross- sectional study at a thyroid cancer referral center in Ecuador 
Salazar-Vega, Jorge , Lincango-Naranjo, Eddy, García, Cristhian, Ortiz‐Prado, Esteban , Ledesma, Tannya, Rojas, Tatiana, Alvarado-Mafla, Benjamin , Cárcamo, Cesar , Solís-Pazmiño, Paola , Jaramillo-Koupermann, Gabriela , Rojas, Tatiana, Carcamo, Cesar, Ponce, Oscar J. , Brito, Juan P.

No container title available | November 20, 2020 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.21203/rs.2.16716/v2 Get It

Abstract Background: In contrast to the rapid increase in thyroid cancer (TC) incidence, thyroid cancer mortality has remained low and stable over the last decades. In Ecuador, however, TC mortality has increased. The objective of this study is to determine possible drivers of high rates of thyroid cancer mortality, through a cross-sectional analysis of all patients attending a thyroid cancer referral center in Ecuador.Methods: From June 2014 to December 2017, a cross-sectional study was conducted at the Hospital de Especialidades Eugenio Espejo (HEEE), a regional reference public hospital for endocrine neoplasia in adults in Quito, Ecuador. We identified the mechanism of detection, histopathology and treatment modalities from a patient interview and review of clinical records. Results: Among 452 patients, 74.8% were young adults and 94.2% (426) were female. 13.7% had a family history of thyroid cancer, and patients’ median tumor size was 2 cm. The incidental finding was 54.2% whereas 45.8% was non-incidental. Thyroid cancer histology reported that 93.3% had papillary thyroid cancer (PTC), 2.7% follicular, 1.5% Hurtle cells, 1.6% medullary, 0.7% poor differentiated, and 0.2% anaplastic carcinoma. The mean MACIS (metastasis, age, completeness, invasion, and size) score was 4.95 (CI 4.15-5.95) with 76.2% of the thyroid cancer patients having MACIS score less than or equal to 6. The very low and low risk of recurrence was 18.1% (79) and 62% (271) respectively. An analysis of 319 patients with non-metastatic thyroid cancer showed that 10.7% (34) of patients had surgical complications. Moreover, around 62.5% (80 from 128 patients with thyroglobulin laboratory results) of TC patients had a stimulated-thyroglobulin (sTg) value equal or higher than 2 ng/ml. Overall, a poor surgical outcome was present in 35.1% (112) patients. Out of 436 patients with differentiated thyroid carcinoma (DTC), 86% (375) received radioactive iodine (RAI). Conclusion: Thyroid cancer histological characteristics and method of diagnosis are like those described in other reports without any evidence of the high frequency of aggressive thyroid cancer histology. However, we observed evidence of overtreatment and poor surgical outcomes that demand additional studies to understand their association with thyroid cancer mortality in Ecuador.
Tumor Frameshift Mutation Proportion Predicts Response to Immunotherapy in Mismatch Repair-Deficient Prostate Cancer
Sena, Laura A. , Fountain, Julia , Lim, Su Jin , Nizialek, Emily , Rathi, Nityam , Maughan, Benjamin L. , Vélez, Miguel González , Ashkar, Ryan, Larson, Amanda , Bryce, Alan H. , Agarwal, Neeraj , Pardoll, Drew M. , Eshleman, James R. , Antonarakis, Emmanuel S. , Antonarakis, Emmanuel S. , Bryce, Alan H , Antonarakis, Emmanuel S , Antonarakis, Emmanuel S , Velho, Pedro Isaacsson , Wang, Hao , Nussenzveig, Roberto , Larson, Amanda C., Pritchard, Colin C. , Adra, Nabil , Agarwal, Neeraj , Lotan, Tamara Levin

The Oncologist | November 20, 2020 | Volume: 26 | Issue: 2 | Pages: e270-e278

10.1002/onco.13601 | PMID 33215787 Get It

Abstract Background Genomic biomarkers that predict response to anti-PD1 therapy in prostate cancer are needed. Frameshift mutations are predicted to generate more neoantigens than missense mutations; therefore, we hypothesized that the number or proportion of tumor frameshift mutations would correlate with response to anti-PD1 therapy in prostate cancer. Methods To enrich for response to anti-PD1 therapy, we assembled a multicenter cohort of 65 men with mismatch repair-deficient (dMMR) prostate cancer. Patient characteristics and outcomes were determined by retrospective chart review. Clinical somatic DNA sequencing was used to determine tumor mutational burden (TMB), frameshift mutation burden, and frameshift mutation proportion (FSP), which were correlated to outcomes on anti-PD1 treatment. We subsequently used data from a clinical trial of pembrolizumab in patients with nonprostatic dMMR cancers of various histologies as a biomarker validation cohort. Results Nineteen of 65 patients with dMMR metastatic castration-resistant prostate cancer were treated with anti-PD1 therapy. The PSA50 response rate was 65%, and the median progression-free survival (PFS) was 24 (95% confidence interval 16–54) weeks. Tumor FSP, more than overall TMB, correlated most strongly with prolonged PFS and overall survival (OS) on anti-PD1 treatment and with density of CD8+ tumor-infiltrating lymphocytes. High FSP similarly identified patients with longer PFS as well as OS on anti-PD1 therapy in a validation cohort. Conclusion Tumor FSP correlated with prolonged efficacy of anti-PD1 treatment among patients with dMMR cancers and may represent a new biomarker of immune checkpoint inhibitor sensitivity. Implications for Practice Given the modest efficacy of immune checkpoint inhibition (ICI) in unselected patients with advanced prostate cancer, biomarkers of ICI sensitivity are needed. To facilitate biomarker discovery, a cohort of patients with DNA mismatch repair-deficient (dMMR) prostate cancer was assembled, as these patients are enriched for responses to ICI. A high response rate to anti-PD1 therapy in these patients was observed; however, these responses were not durable in most patients. Notably, tumor frameshift mutation proportion (FSP) was identified as a novel biomarker that was associated with prolonged response to anti-PD1 therapy in this cohort. This finding was validated in a separate cohort of patients with nonprostatic dMMR cancers of various primary histologies. This works suggests that FSP predicts response to anti-PD1 therapy in dMMR cancers, which should be validated prospectively in larger independent cohorts.