A dual-receptor T-cell platform with Ab-TCR and costimulatory receptor achieves specificity and potency against AML.

ABSTRACT: Chimeric antigen receptor T-cell (CAR T) therapy has produced remarkable clinical responses in B-cell neoplasms. However, many challenges limit this class of agents for the treatment of other cancer types, in particular the lack of tumor-selective antigens for solid tumors and other hematological malignancies, such as acute myeloid leukemia (AML), which may be addressed without significant risk of severe toxicities while providing sufficient abundance for efficient tumor suppression. One approach to overcome this hurdle is dual targeting by an antibody-T-cell receptor (AbTCR) and a chimeric costimulatory signaling receptor (CSR) to 2 different antigens, in which both antigens are found together on the cancer cells but not together on normal cells. To explore this proof of concept in AML, we engineered a new T-cell format targeting Wilms tumor 1 protein (WT1) and CD33; both are highly expressed on most AML cells. Using an AbTCR comprising a newly developed TCR-mimic monoclonal antibody against the WT1 RMFPNAPYL (RMF) epitope/HLA-A2 complex, ESK2, and a secondary CSR comprising a single-chain variable fragment directed to CD33 linked to a truncated CD28 costimulatory fragment, this unique platform confers specific T-cell cytotoxicity to the AML cells while sparing healthy hematopoietic cells, including CD33+ myelomonocytic normal cells. These data suggest that this new platform, named AbTCR-CSR, through the combination of a AbTCR CAR and CSR could be an effective strategy to reduce toxicity and improve specificity and clinical outcomes in adoptive T-cell therapy in AML.

Positioning Transclival Tumor-Treating Fields for the Treatment of Diffuse Intrinsic Pontine Gliomas.

Diffuse intrinsic pontine glioma (DIPG) carries an extremely poor prognosis, with 2-year survival rates of <10% despite the maximal radiation therapy. DIPG cells have previously been shown to be sensitive to low-intensity electric fields in vitro. Accordingly, we sought to determine if the endoscopic endonasal (EE) implantation of an electrode array in the clivus would be feasible for the application of tumor-treating fields (TTF) in DIPG. Anatomic constraints are the main limitation in pediatric EE approaches. In our Boston Children's Hospital's DIPG cohort, we measured the average intercarotid distance (1.68 ± 0.36 cm), clival width (1.62 ± 0.19 cm), and clival length from the base of the sella (1.43 ± 0.69 cm). Using a linear regression model, we found that only clival length and sphenoid pneumatization were significantly associated with age (R2 = 0.568, p = 0.005 *; R2 = 0.605, p = 0.0002 *). Critically, neither of these parameters represent limitations to the implantation of a device within the dimensions of those currently available. Our findings confirm that the anatomy present within this age group is amenable to the placement of a 2 × 1 cm electrode array in 94% of patients examined. Our work serves to demonstrate the feasibility of implantable transclival devices for the provision of TTFs as a novel adjunctive therapy for DIPG.

Reduced time to imaging, length of stay, and hospital charges following implementation of a novel postoperative pathway for craniotomy.

OBJECTIVE: The authors created a postoperative postanesthesia care unit (PACU) pathway to bypass routine intensive care unit (ICU) admissions of patients undergoing routine craniotomies, to improve ICU resource utilization and reduce overall hospital costs and lengths of stay while maintaining quality of care and patient satisfaction. In the present study, the authors evaluated this novel PACU-to-floor clinical pathway for a subset of patients undergoing craniotomy with a case time under 5 hours and blood loss under 500 ml. METHODS: A single-institution retrospective cohort study was performed to compare 202 patients enrolled in the PACU-to-floor pathway and 193 historical controls who would have met pathway inclusion criteria. The pathway cohort consisted of all adult supratentorial brain tumor cases from the second half of January 2021 to the end of January 2022 that met the study inclusion criteria. Control cases were selected from the beginning of January 2020 to halfway through January 2021. The authors also discuss common themes of similar previously published pathways and the logistical and clinical barriers overcome for successful PACU pathway implementation. RESULTS: Pathway enrollees had a median age of 61 years (IQR 49-69 years) and 53% were female. Age, sex, pathology, and American Society of Anesthesiologists physical status distributions were similar between pathway and control patients (p > 0.05). Most of the pathway cases (96%) were performed on weekdays, and 31% had start times before noon. Nineteen percent of pathway patients had 30-day readmissions, most frequently for headache (16%) and syncope (10%), whereas 18% of control patients had 30-day readmissions (p = 0.897). The average time to MRI was 6 hours faster for pathway patients (p < 0.001) and the time to inpatient physical therapy and/or occupational therapy evaluation was 4.1 hours faster (p = 0.046). The average total length of stay was 0.7 days shorter for pathway patients (p = 0.02). A home discharge occurred in 86% of pathway cases compared to 81% of controls (p = 0.225). The average total hospitalization charges were $13,448 lower for pathway patients, representing a 7.4% decrease (p = 0.0012, adjusted model). Seven pathway cases were escalated to the ICU postoperatively because of attending physician preference (2 cases), agitation (1 case), and new postoperative neurological deficits (4 cases), resulting in a 96.5% rate of successful discharge from the pathway. In bypassing the ICU, critical care resource utilization was improved by releasing 0.95 ICU days per patient, or 185 ICU days across the cohort. CONCLUSIONS: The featured PACU-to-floor pathway reduces the stay of postoperative craniotomy patients and does not increase the risk of early hospital readmission.

Utilization of Discarded Surgical Tissue from Ultrasonic Aspirators to Establish Patient-Derived Metastatic Brain Tumor Cells: A Guide from the Operating Room to the Research Laboratory.

Patient-derived cells from surgical resections are of paramount importance to brain tumor research. It is well known that there is cellular and microenvironmental heterogeneity within a single tumor mass. Thus, current established protocols for propagating tumor cells in vitro are limiting because resections obtained from conventional singular samples limit the diversity in cell populations and do not accurately model the heterogeneous tumor. Utilization of discarded tissue obtained from cavitron ultrasonic surgical aspirator (CUSA) of the whole tumor mass allows for establishing novel cell lines in vitro from the entirety of the tumor, thereby creating an accurate representation of the heterogeneous population of cells originally present in the tumor. Furthermore, while others have described protocols for establishing patient tumor lines once tissue has arrived in the research lab, a primer from the operating room (OR) to the research lab has not been described before. This is integral, as basic research scientists need to understand the surgical environment of the OR, including the methods utilized to obtain a patient's tumor resection, in order to more accurately model cancer biology in laboratory. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Establishment of brain tumor cell lines from patient-derived CUSA samples: processing brain tumor sample from the OR to the lab Support Protocol 1: Sterilization of microsurgical tools in preparation for dissection Support Protocol 2: Collagen coating of tissue culture flasks Basic Protocol 2: Selection of tumor cells in vitro Support Protocol 3: FACS sorting tumor sample to isolate cancer cells from heterogeneous cell population.

Comorbid depression in surgical cancer patients associated with non-routine discharge and readmission.

OBJECTIVE: To characterize the rates of depression across primary cancer sites, and determine the effects of comorbid depression among surgical cancer patients on established quality of care indicators, non-routine discharge and readmission. METHODS: Patients undergoing surgical resection for cancer were selected from the Nationwide Readmissions Database (2010-2014). Multivariable analysis adjusted for patient and hospital level characteristics to ascertain the effect of depression on post-operative outcomes and 30-day readmission rates. Non-routine discharge encompasses discharge to skilled nursing, inpatient rehabilitation, and intermediate care facilities, as well as discharge home with home health services. RESULTS: Among 851,606 surgically treated cancer patients, 8.1% had a comorbid diagnosis of depression at index admission (n = 69,174). Prevalence of depression was highest among patients with cancer of the brain (10.9%), female genital organs (10.9%), and lung (10.5%), and lowest among those with prostate cancer (4.9%). Depression prevalence among women (10.9%) was almost twice that of men (5.7%). Depression was associated with non-routine discharge after surgery (OR 1.20, CI:1.18-1.23, p < 0.0001*) and hospital readmission within 30 days (OR 1.12, CI:1.09-1.15, p < 0.001*). CONCLUSION: Rates of depression vary amongst surgically treated cancer patients by primary tumor site. Comorbid depression in these patients is associated with increased likelihood of non-routine discharge and readmission.

Frailty Is Associated with In-Hospital Morbidity and Nonroutine Disposition in Brain Tumor Patients Undergoing Craniotomy.

OBJECTIVE: Frailty is associated with postoperative morbidity in multiple surgical disciplines. We evaluated the association between frailty and early postoperative outcomes for brain tumor patients using a national database. METHODS: We reviewed the Nationwide Readmissions Database from 2010 to 2014. International Classification of Diseases, ninth revision, codes were used to identify benign and malignant brain tumors treated with surgical resection. Pituitary tumors were excluded. Frailty was assessed using the Johns Hopkins Adjusted Clinical Groups frailty indicator tool. Multivariable exact logistic regression was used to conduct analyses assessing the association between frailty and the outcome variables. Statistical significance was defined as P < 0.001. RESULTS: The criteria for frailty were met for 7209 of 87,835 patients (8.2%). After adjustment for patient and hospital factors, frailty was independently associated with in-hospital surgical complications (odds ratio [OR], 1.48; 95% confidence interval [CI] 1.37-1.59; P < 0.0001), mental status changes (OR, 1.9; 95% CI, 1.72-2.09; P < 0.0001), and pulmonary insufficiency (OR, 1.75; 95% CI, 1.55-1.96; P < 0.0001). Frailty was associated with an increased length of stay (incident rate ratio, 1.92; 95% CI, 1.87-1.98; P < 0.0001) and nonroutine disposition (OR, 1.84; 95% CI, 1.72-1.97; P < 0.0001). In-hospital mortality was greater for frail patients (2.2% vs. 1.4%; P < 0.0001), but the difference did not achieve significance on multivariate analysis. Frail patients were not more likely to be readmitted. CONCLUSION: Frailty is associated with in-hospital complications and nonroutine disposition after craniotomy for benign and malignant brain tumors. Additional work is needed to identify prehabilitation or in-hospital strategies to improve the care and outcomes of these at-risk patients.

Readmission with venous thromboembolism after surgical treatment by primary cancer site.

BACKGROUND: Venous thromboembolism (VTE) is a common, high-mortality condition among surgical cancer patients. Comprehensive analyses of VTE among postoperative cancer patients are lacking. We sought to determine the association between readmission with VTE and primary cancer diagnosis in a nationwide database at 90- and 180-days after initial admission for cancer surgery. METHODS: Retrospective analyses of post-surgical cancer patients readmitted with VTE were conducted using data from the Nationwide Readmissions Database (NRD) (2010-2014). Multivariate logistic regression models adjusting for patient and hospital factors were used to determine 90- and 180-day readmission rates for VTE by cancer type. Patient factors associated with readmission were also examined. RESULTS: Among a sample of 535,992 cancer patients undergoing tumor resection, readmission with VTE occurred in 1.7% within 90-days and 2.3% within 180-days. Patients readmitted for VTE experienced a 7% mortality rate. Highest rates of VTE readmission at 180 days occurred in brain (6.7%), pancreatic (5.6%), and respiratory and intrathoracic cancers (4.4%). Using pancreatic cancer as reference, brain cancer had the highest odds of readmission at 180-days (OR 2.23, 95% CI [1.95-2.55]). CONCLUSION: Readmission with VTE among surgical cancer patients occurred in 2.3% of patients within 180 days. Among cancer types, primary brain cancer was independently associated with readmission with VTE.

Comorbid depression associated with non-routine discharge following craniotomy for low-grade gliomas and benign tumors - a nationwide readmission database analysis.

PURPOSE: Prior studies have demonstrated elevated rates of depression in patients with malignant brain tumor; however, the prevalence and effect on surgical outcomes in patients with low-grade gliomas (LGG) and benign brain tumors (BBT) remain unknown. Readmission and non-routine discharge, which includes discharge to skilled nursing, rehabilitative, and other inpatient facilities, are well-established quality of care indicators. We sought to analyze the association between comorbid depression and non-routine discharge, readmission, and other post-operative inpatient outcomes in patients with LGG and BBT. METHODS: The Nationwide Readmissions Database from 2010 to 2014 was retrospectively queried to select for surgically treated patients with LGG and BBT. Multivariable logistic regression models adjusting for patient and hospital characteristics were used to determine the effects of comorbid depression on post-operative outcomes. Interaction of gender and depression on non-routine disposition was analyzed. RESULTS: We identified 31,654 craniotomies for resection of BBT and LGG (2010-2014). The majority of patients (64.1%) were female. The rate of depression comorbid with BBT and LGG was 11.9%. Depression was associated with non-routine discharge after surgery (OR 1.19, p 0.0002*), but was not associated with increased morbidity, mortality, or readmission at 30 or 90 days. The rate of comorbid depression was higher among female than male patients (14.0 vs. 8.0%). Depression in males was associated with a 38% increased likelihood of non-routine disposition (p = 0.0002*), while depression in females was associated with a 13% increased likelihood of non-routine disposition (p = 0.03*). CONCLUSION: Depression is prevalent in patients with LGG and BBT and is associated with increased risk of non-routine discharge following surgical intervention. The increased likelihood of non-routine disposition is greater for males than that for females. Awareness of the risk factors for depression may aid in early screening and intervention and improve overall patient outcomes.

Readmission following inpatient stereotactic radiosurgery for brain tumors.

BACKGROUND: Stereotactic radiosurgery (SRS) is indicated for a spectrum of brain tumors and is often an outpatient procedure, though severe disease may precipitate inpatient treatment. Readmission following inpatient SRS for brain tumors is not well understood. OBJECTIVES: To characterize rate, associative factors, and predictors of SRS readmission. METHODS: Retrospective analysis of inpatients treated with SRS for brain neoplasms was conducted (2010-2014 Nationwide Readmissions Database). Diagnoses upon readmission were characterized. Associations with 30-day readmission were identified using multivariate analyses. RESULTS: Of 2,553 patients undergoing SRS, 390 were readmitted (15.3%) within 30 days. Leading readmission diagnoses were infectious or embolic. Neurological readmissions of intracerebral hemorrhage (2.1%) and cerebral edema (1.5%) were rare. Malignant tumors (OR=1.60, p=0.007) and discharge to facility (OR=1.41, p=0.004) were associated with readmission. CONCLUSION: Inpatients receiving SRS for brain tumors have a 15.3% 30-day readmission rate. Neurologic readmissions were rare, underscoring the neurological safety of SRS, even in sick inpatients.

Increased complication and mortality among non-index hospital readmissions after brain tumor resection is associated with low-volume readmitting hospitals.

OBJECTIVE: Fragmentation of care following craniotomy for tumor resection is increasingly common with the regionalization of neurosurgery. Hospital readmission to a hospital (non-index) other than the one from which patients received their original care (index) has been associated with increases in both morbidity and mortality for cancer patients. The impact of non-index readmission after surgical management of brain tumors has not previously been evaluated. The authors set out to determine rates of non-index readmission following craniotomy for tumor resection and evaluated outcomes following index and non-index readmissions. METHODS: Retrospective analyses of data from cases involving resection of a primary brain tumor were conducted using data from the Nationwide Readmissions Database (NRD) for 2010-2014. Multivariate logistic regression was used to evaluate the independent association of patient and hospital factors with readmission to an index versus non-index hospital. Further analysis evaluated association of non-index versus index hospital readmission with mortality and major complications during readmission. Effects of readmission hospital procedure volume on mortality and morbidity were evaluated in post hoc analysis. RESULTS: In a total of 17,459 unplanned readmissions, 84.4% patients were readmitted to index hospitals and 15.6% to non-index hospitals. Patient factors associated with increased likelihood of non-index readmission included older age (75+: OR 1.44, 95% CI 1.19-1.75), elective index admission (OR 1.19, 95% CI 1.08-1.30), increased Elixhauser comorbidity score ≥2 (OR 1.18, 95% CI 1.01-1.37), and malignant tumor diagnosis (OR 1.32, 95% CI 1.19-1.45) (all p < 0.04). Readmission to a non-index facility was associated with a 28% increase in major complications (OR 1.28, 95% CI 1.14-1.43, p < 0.001) and 21% increase in mortality (OR 1.21, 95% CI 1.02-1.44, p = 0.032) in initial analysis. Following a second multivariable logistic regression analysis including the readmitting hospital characteristics, low procedure volume of a readmitting facility was significantly associated with non-index readmission (p < 0.001). Readmission to a lower-procedure-volume facility was associated with a 46%-75% increase in mortality (OR 1.46-1.75, p < 0.005) and a 21%-35% increase in major complications (OR 1.21-1.34, p < 0.005). Following adjustment for volume at a readmitting facility, admission to a non-index facility was no longer associated with mortality (OR 0.90, 95% CI 0.71-1.14, p = 0.378) or major complications (OR 1.09, CI 0.94-1.26, p = 0.248). CONCLUSIONS: Of patient readmissions following brain tumor resection, 15.6% occur at a non-index facility. Low procedure volume is a confounder for non-index analysis and is associated with an increased likelihood of major complications and mortality, as compared to readmission to high-procedure-volume hospitals. Further studies should evaluate interventions targeting factors associated with unplanned readmission.

Clinical utility of FoundationOne tissue molecular profiling in men with metastatic prostate cancer.

PURPOSE: Targeted inhibitors and immunotherapy have entered the treatment landscape of metastatic prostate cancer. Genomic testing may uncover which patients benefit most from these therapies. We report the clinical utility and benefits of FoundationOne testing in men with advanced prostate cancer. PATIENTS AND METHODS: We retrospectively identified all men with prostate cancer who received tissue FoundationOne testing at our institution between January 2010 and April 2017. Genomic alterations, treatment selection based on FoundationOne results, and clinical outcomes including response and duration of therapy following matched targeted therapy were analyzed. RESULTS: A total of 77 men with metastatic prostate cancer were referred for FoundationOne testing; 59 (77%) had sufficient tumor tissue for testing. Of these, 22% (17/77) of men had a targetable mutation and 9% (7/77) of men received matched off-label targeted therapy. Overall, 5% (4/77) of patients derived clinical benefit. One patient with a BRCA2 loss had a complete response on olaparib (>27 months) and 3 patients (ATM substitution, PALB2 frameshift, CDK12 frameshift) had stable disease with olaparib (10.3, 18.7, and 7.8 months, respectively). Three patients (BRCA2 frameshift, PDL1 + PDL2 amplification, PMS2 missense) had progressive disease despite targeted therapy. CONCLUSIONS: Tissue genomic testing can uncover patients who may benefit from targeted therapies such as poly(adenosine diphosphate-ribose) polymerase inhibitors or immunotherapy. In our limited single institution study, genomic testing led to clinical benefit in 5% of patients. Combined germline and circulating tumor DNA testing may be helpful to identify additional patients suitable for matched genomic therapies.

Depleting T regulatory cells by targeting intracellular Foxp3 with a TCR mimic antibody.

Depletion of T regulatory cells (Tregs) in the tumor microenvironment is a promising cancer immunotherapy strategy. Current approaches for depleting Tregs are limited by lack of specificity and concurrent depletion of anti-tumor effector T cells. The transcription factor forkhead box p3 (Foxp3) plays a central role in the development and function of Tregs and is an ideal target in Tregs, but Foxp3 is an intracellular, undruggable protein to date. We have generated a T cell receptor mimic antibody, "Foxp3-#32," recognizing a Foxp3-derived epitope in the context of HLA-A*02:01. The mAb Foxp3-#32 selectively recognizes CD4 + CD25 + CD127low and Foxp3 + Tregs also expressing HLA-A*02:01 and depletes these cells via antibody-mediated cellular cytotoxicity. Foxp3-#32 mAb depleted Tregs in xenografts of PBMCs from a healthy donor and ascites fluid from a cancer patient. A TCRm mAb targeting intracellular Foxp3 epitope represents an approach to deplete Tregs.

Extending julius seizure, a bang-sensitive gene, as a model for studying epileptogenesis: Cold shock, and a new insertional mutation.

The bang-sensitive (BS) mutants of Drosophila are an important model for studying epilepsy. We recently identified a novel BS locus, julius seizure (jus), encoding a protein containing two transmembrane domains and an extracellular cysteine-rich loop. We also determined that jussda iso7.8, a previously identified BS mutation, is an allele of jus by recombination, deficiency mapping, complementation testing, and genetic rescue. RNAi knockdown revealed that jus expression is important in cholinergic neurons and that the critical stage of jus expression is the mid-pupa. Finally, we found that a functional, GFP-tagged genomic construct of jus is expressed mostly in axons of the neck connectives and of the thoracic abdominal ganglia. In this Extra View article, we show that a MiMiC GFP-tagged Jus is localized to the same nervous system regions as the GFP-tagged genomic construct, but its expression is mostly confined to cell bodies and it causes bang-sensitivity. The MiMiC GFP-tag lies in the extracellular loop while the genomic construct is tagged at the C-terminus. This suggests that the alternate position of the GFP tag may disrupt Jus protein function by altering its subcellular localization and/or stability. We also show that a small subset of jus-expressing neurons are responsible for the BS phenotype. Finally, extending the utility of the BS seizure model, we show that jus mutants exhibit cold-sensitive paralysis and are partially sensitive to strobe-induced seizures.

A therapeutic T cell receptor mimic antibody targets tumor-associated PRAME peptide/HLA-I antigens.

Preferentially expressed antigen in melanoma (PRAME) is a cancer-testis antigen that is expressed in many cancers and leukemias. In healthy tissue, PRAME expression is limited to the testes and ovaries, making it a highly attractive cancer target. PRAME is an intracellular protein that cannot currently be drugged. After proteasomal processing, the PRAME300-309 peptide ALYVDSLFFL (ALY) is presented in the context of human leukocyte antigen HLA-A*02:01 molecules for recognition by the T cell receptor (TCR) of cytotoxic T cells. Here, we have described Pr20, a TCR mimic (TCRm) human IgG1 antibody that recognizes the cell-surface ALY peptide/HLA-A2 complex. Pr20 is an immunological tool and potential therapeutic agent. Pr20 bound to PRAME+HLA-A2+ cancers. An afucosylated Fc form (Pr20M) directed antibody-dependent cellular cytotoxicity against PRAME+HLA-A2+ leukemia cells and was therapeutically effective against mouse xenograft models of human leukemia. In some tumors, Pr20 binding markedly increased upon IFN-γ treatment, mediated by induction of the immunoproteasome catalytic subunit ß5i. The immunoproteasome reduced internal destructive cleavages within the ALY epitope compared with the constitutive proteasome. The data provide rationale for developing TCRm antibodies as therapeutic agents for cancer, offer mechanistic insight on proteasomal regulation of tumor-associated peptide/HLA antigen complexes, and yield possible therapeutic solutions to target antigens with ultra-low surface presentation.

An immunogenic WT1-derived peptide that induces T cell response in the context of HLA-A*02:01 and HLA-A*24:02 molecules.

The Wilms' tumor oncogene protein (WT1) is a highly validated tumor antigen for immunotherapy. WT1-targeted immunotherapy has been extensively explored in multiple human trials in various cancers. However, clinical investigations using WT1 epitopes have generally focused on two peptides, HLA-restricted to HLA-A*02:01 or HLA-A*24:02. The goal of this study was to identify new epitopes derived from WT1, to expand the potential use of WT1 as a target of immunotherapy. Using computer-based MHC-binding algorithms and in vitro validation of the T cell responses specific for the identified peptides, we found that a recently identified HLA-A*24:02-binding epitope (239-247), NQMNLGATL (NQM), was also a strong CD8+ T cell epitope for HLA-A*02:01 molecule. A peptide second position Q240L substitution (NLM) or Q240Y substitution (NYM), further enhanced the T cell responses in both HLA-A*02:01 positive and HLA-A*24:02 positive healthy donors. Importantly, T cells stimulated with the new analog peptides displayed heteroclitic cross-reactivity with the native NQM sequence and were able to kill HLA-matched WT1-positive tumor cell lines and primary leukemia blasts. In addition, longer native and heteroclitic HLA-DR.B1-binding peptides, comprising the nine amino acid NQM or NLM sequences, could induce T cell response that recognized the CD8+ epitope NQM, suggesting the processing and the presentation by HLA-A*02:01 molecules of the CD8+ T cell epitope embedded within it. Our studies suggest that the analog peptides NLM and NYM could be potential candidates for future immunotherapy targeting WT1 positive cancers in the context of HLA-A*02:01 and A*24:02 positive populations.

Kinase Regulation of Human MHC Class I Molecule Expression on Cancer Cells.

The major histocompatibility complex I (MHC-1) presents antigenic peptides to tumor-specific CD8+ T cells. The regulation of MHC-I by kinases is largely unstudied, even though many patients with cancer are receiving therapeutic kinase inhibitors. Regulators of cell-surface HLA amounts were discovered using a pooled human kinome shRNA interference-based approach. Hits scoring highly were subsequently validated by additional RNAi and pharmacologic inhibitors. MAP2K1 (MEK), EGFR, and RET were validated as negative regulators of MHC-I expression and antigen presentation machinery in multiple cancer types, acting through an ERK output-dependent mechanism; the pathways responsible for increased MHC-I upon kinase inhibition were mapped. Activated MAPK signaling in mouse tumors in vivo suppressed components of MHC-I and the antigen presentation machinery. Pharmacologic inhibition of MAPK signaling also led to improved peptide/MHC target recognition and killing by T cells and TCR-mimic antibodies. Druggable kinases may thus serve as immediately applicable targets for modulating immunotherapy for many diseases. Cancer Immunol Res; 4(11); 936-47. ©2016 AACR.