Double-modified oncolytic adenovirus armed with a recombinant interferon-like gene enhanced abscopal effects against malignant glioma.

Background: The development of new therapies for malignant gliomas has been stagnant for decades. Through the promising outcomes in clinical trials of oncolytic virotherapy, there is now a glimmer of hope in addressing this situation. To further enhance the antitumor immune response of oncolytic viruses, we have equipped a modified oncolytic adenovirus (oAds) with a recombinant interferon-like gene (YSCH-01) and conducted a comprehensive evaluation of the safety and efficacy of this modification compared to existing treatments. Methods: To assess the safety of YSCH-01, we administered the oAds intracranially to Syrian hamsters, which are susceptible to adenovirus. The efficacy of YSCH-01 in targeting glioma was evaluated through in vitro and in vivo experiments utilizing various human glioma cell lines. Furthermore, we employed a patient-derived xenograft model of recurrent glioblastoma to test the effectiveness of YSCH-01 against temozolomide. Results: By modifying the E1A and adding survivin promoter, the oAds have demonstrated remarkable safety and an impressive ability to selectively target tumor cells. In animal models, YSCH-01 exhibited potent therapeutic efficacy, particularly in terms of its distant effects. Additionally, YSCH-01 remains effective in inhibiting the recurrent GBM patient-derived xenograft model. Conclusions: Our initial findings confirm that a double-modified oncolytic adenovirus armed with a recombinant interferon-like gene is both safe and effective in the treatment of malignant glioma. Furthermore, when utilized in combination with a targeted therapy gene strategy, these oAds exhibit a more profound effect in tumor therapy and an enhanced ability to inhibit tumor growth at remote sites.

The cortical regions and white matter tracts underlying auditory comprehension in patients with primary brain tumor.

The comprehension of spoken language is one of the most essential language functions in humans. However, the neurological underpinnings of auditory comprehension remain under debate. Here we used multi-modal neuroimaging analyses on a group of patients with low-grade gliomas to localize cortical regions and white matter tracts responsible for auditory language comprehension. Region-of-interests and voxel-level whole-brain analyses showed that cortical areas in the posterior temporal lobe are crucial for language comprehension. The fiber integrity assessed with diffusion tensor imaging of the arcuate fasciculus and the inferior longitudinal fasciculus was strongly correlated with both auditory comprehension and the grey matter volume of the inferior temporal and middle temporal gyri. Together, our findings provide direct evidence for an integrated network of auditory comprehension whereby the superior temporal gyrus and sulcus, the posterior parts of the middle and inferior temporal gyri serve as auditory comprehension cortex, and the arcuate fasciculus and the inferior longitudinal fasciculus subserve as crucial structural connectivity. These findings provide critical evidence on the neural underpinnings of language comprehension.

Endothelial cells by inactivation of VHL gene direct angiogenesis, not vasculogenesis via Twist1 accumulation associated with hemangioblastoma neovascularization.

Inactivation of the VHL tumour suppressor gene is a highly frequent genetic event in the carcinogenesis of central nervous system-(CNS) hemangioblastomas (HBs). The patterning of the similar embryonic vasculogenesis is an increasing concern in HB-neovascularization, and the classic vascular endothelial growth factor (VEGF)-mediated angiogenesis driven by VHL loss-of-function from human endothelium have been questioned. With this regard, we identify a distinct, VHL silencing-driven mechanism in which human vascular endothelial cells by means of increasing cell proliferation and decreasing cell apoptosis, is concomitant with facilitating accumulation of Twist1 protein in vascular endothelial cells in vitro. Importantly, this molecular mechanism is also pinpointed in CNS-HBs, and associated with the process of HB-neovascularization. In contrast with recent studies of HB-neovascularization, these modified cells did not endow with the typical features of vasculogenesis, indicating that this is a common angiogenesis implementing the formation of the vascular network. Taken together, these findings suggest that vasculogenesis and angiogenesis may constitute complementary mechanisms for HB-neovascularization, and could provide a rational recognition of single anti-angiogenic intervention including targeting to the Twist1 signalling for HBs.

Effects of Deferoxamine Mesylate on Hematoma and Perihematoma Edema after Traumatic Intracerebral Hemorrhage.

Deferoxamine mesylate can cross the blood-brain barrier and reduce iron accumulation in nervous tissue; moreover, it has a variety of neuroprotective functions in addition to complexing with iron ions. Such iron chelators are expected to become a new treatment option for intracerebral hemorrhage. This study evaluated the effects of deferoxamine mesylate on hematoma and edema absorption after traumatic intracerebral hemorrhage (TICH), and it provides clinical evidence for TICH treatment with deferoxamine mesylate. Patients with isolated TICH, confirmed by head computed tomography, were enrolled prospectively from January 2013 to December 2016. Patients were divided non-randomly into an experimental or control group as decided by the attending neurosurgeon. Patients in the experimental group received intravenous deferoxamine mesylate (20 mg/kg daily) from the day of admission for 5 consecutive days. We evaluated the impact of deferoxamine mesylate on the change in edema volume and the absorption of hematoma volume using a propensity score-matched analysis. In total, 190 patients were included. After matching, 94 patients were included in the final analysis (47 per group); no variable differed significantly between the two groups. The hematoma volume on the 7th day in the control group was higher than that at the same time-point in the experimental group (9.4 ± 7.2 vs. 5.2 ± 4.8 mL; p = 0.001). There was no difference in hematoma volume on Day 1 (12.6 ± 7.8 vs. 12.8 ± 6.4 mL; p = 0.896), Day 3 (12.4 ± 7.4 vs. 11.4 ± 4.9 mL; p = 0.442), and Day 14 (3.2 ± 3.0 vs. 2.5 ± 2.6 mL; p = 0.215) between the groups. The absorption of hematoma volume between the 1st and 3rd days and the 1st and 7th days in the experimental group was higher than that during the same periods in the control group. The edema volumes on the 3rd, 7th, and 14th days in the control group were higher than those at the same time-points in the experimental group. There was no difference in edema volume on the 1st day. The changes in edema volume between the 1st and 3rd days, the 1st and 7th days, and the 1st and 14th days in the control group were higher than those during the same periods in the experimental group. Deferoxamine mesylate may accelerate hematoma absorption and inhibit edema after TICH; however, further investigation is required to reach definitive conclusions.

Unforgettable Ups and Downs of Acupuncture Anesthesia in China.

BACKGROUND: Acupuncture anesthesia originated from the pain relief and pain prevention theory in acupuncture and moxibustion. This technique is a new exploration of anesthesiology and an original achievement of China, representing a landmark combination of Traditional Chinese Medicine and Western medicine. OBJECTIVES: The aim of this historical vignette to introduce acupuncture anesthesia with its meaningful history, especially the use in neurosurgery to the public. DESIGN: This historical vignette introduced the development, mechanism research, awake craniotomy, in order to analyze the utility of acupuncture anesthesia, its global impact, the current situation and future of acupuncture anesthesia. CONCLUSION: Acupuncture anesthesia was initiated in 1958, and, reflecting the historical background of China after the 1960s, the use of this technique spread widely throughout the country. Reaching other countries after 1971, acupuncture anesthesia had a significant influence, drawing attention from medical academia worldwide. Thus, acupuncture anesthesia has made a special contribution to the medical science of modern China.

Recent advances in molecular biology and treatment strategies for intracranial germ cell tumors.

BACKGROUND: Intracranial germ cell tumors (IGCTs) are a group of rare pediatric brain tumors which include various subtypes. The current understanding of the etiology of the tumors and their optimal management strategies remain controversial. DATA SOURCES: The data on IGCTs were collected from articles published in the past 20 years, and the origin and etiology of IGCTs at molecular level as well as the relative roles of varied treatment strategies in different prognosis groups according to Matsutani's classification were reviewed. RESULTS: Recent cellular and molecular evidence suggests that IGCTs may arise from the transformation of endogenous brain cells; and findings in the molecular characterization of IGCTs suggest roles of CCND2, RB1, and PRDM14 in the pathogenesis of IGCTs and identify the KIT/RAS and AKT1/mTOR pathways as potential therapeutic targets in future. According to Matsutani's classification of IGCTs, the good prognosis group includes both germinomas and mature teratomas. For germinomas, both radiation alone and reduced-dose radiotherapy in combination with adjuvant chemotherapy are effective, while complete surgical excision is recommended for mature teratomas. In the intermediate prognosis group, immature teratoma has been successfully treated with gamma knife surgery. However, for intermediate prognosis IGCTs other than immature teratomas, gross total resection with adjuvant chemotherapy and radiotherapy or gamma knife surgery may be necessary to achieve cure. In the poor prognosis group, survival outcomes are unsatisfactory, and complete surgical resection combined with more intensive chemotherapy and radiotherapy remains the best available treatment option at this time. CONCLUSIONS: IGCTs should be strictly classified according to their pathological categories before administering pathology-specific treatments. Although open microsurgical excision is the traditional surgical strategy for IGCTs, recent publications also support the role of endoscopic surgical options for pineal region IGCTs.

Intraoperative Multi-Information-Guided Resection of Dominant-Sided Insular Gliomas in a 3-T Intraoperative Magnetic Resonance Imaging Integrated Neurosurgical Suite.

OBJECTIVE: To evaluate the clinical application of 3-T intraoperative magnetic resonance imaging (iMRI), awake craniotomy, multimodal functional mapping, and intraoperative neurophysiologic monitoring (IONM) for resection of dominant-sided insular gliomas. METHODS: From March 2011 to June 2013, 30 gliomas involving the dominant insular lobe were resected in the IMRIS 3.0-T iMRI integrated neurosurgical suite. For 20 patients, awake craniotomy with cortical electrical stimulation mapping was performed to locate the language areas. For 10 patients who were not suitable for awake surgery, general anesthesia and functional navigation were performed. Diffusion tensor imaging tractography-based navigation, continuous motor evoked potential monitoring, and subcortical electrical stimulation mapping were applied to localize and monitor the motor pathway in all cases. iMRI was used to assess the extent of resection. The results of intraoperative imaging, IONM, and the surgical consequences were analyzed. RESULTS: Intraoperative imaging revealed residual tumor in 26 cases and led to further resection in 9 cases. As a result, the median extent of resection was increased from 90% to 93% (P = 0.008) in all cases, and from 88% to 92% (P = 0.018) in low-grade gliomas. The use of iMRI also resulted in an increase in the percentage of gross and near total resection from 53% to 77% (P = 0.016). The rates of permanent language and motor deficits resulting from tumor removal were 11% and 7.1%, respectively. CONCLUSIONS: The combination of iMRI, awake craniotomy, multimodal brain mapping, and IONM tailored for each patient permits the maximal safe resection of dominant-sided insular glioma.

Coagulopathy in Traumatic Brain Injury and Its Correlation with Progressive Hemorrhagic Injury: A Systematic Review and Meta-Analysis.

The association between coagulopathy and either isolated traumatic brain injury (TBI) or progressive hemorrhagic injury (PHI) remains controversial. The aims of this study were to evaluate whether isolated TBI induces pronounced coagulopathy, in comparison with non-TBI or TBI in conjunction with other injuries (TBI + other injuries), and to examine whether there is any evidence of a relationship between coagulopathy and PHI in patients who have experienced TBI. The MEDLINE(®) and Embase databases, and the Cochrane Central Register of Controlled Trials (Central), were trawled for relevant studies. Searches covered the period from the inception of each of the databases to June 2015, and were conducted using appropriate combinations of terms and key words based on medical subject headings (MeSH). Studies were included if they compared isolated TBI with a similar severity of injury to other body regions, or compared PHI with non-PHI, with regard to coagulation tests and the prevalence of coagulopathy. We extracted the means and standard deviations (SD) of coagulation test levels, as well as their ranges or the percentage of abnormal coagulation tests, in both cases and controls. A total of 19 studies were included in our systematic review and meta-analysis. Only the mean fibrinogen (FIB) in isolated TBI was found to be significantly higher than in TBI + other injuries (pooled mean difference [MD] 32.09; 95% confidence interval [CI] 4.92-59.25; p = 0.02); in contrast, it was also significantly higher than in non-TBI (pooled MD 15.44; 95% CI 0.28-30.59; p = 0.05). We identified 15 studies that compared coagulopathy between a PHI group and a non-PHI group. The PHI group had a lower platelet count (PLT) value (pooled MD -19.21; 95% CI: -26.99 to -11.44, p < 0.001) and a higher international normalized ratio (INR) value (pooled MD 0.07; 95% CI: 0.02-0.13, p = 0.006) than the non-PHI group, but no differences were observed in the mean activated partial thromboplastin time (APTT) and prothrombin time (PT) between the PHI and non-PHI patients. In addition, PHI was significantly associated with a higher percentage of INR >1.2 (pooled OR 3.49 [95% CI 1.97-6.20], p < 0.001), PLT <100 × 109/L (pooled OR 4.74 [95% CI 2.44-9.20], p < 0.001), and coagulopathy (pooled OR 2.52; 95% CI 1.88- 3.38; p < 0.001), compared with non-PHI. The current clinical evidence does not indicate that the prevalence of coagulopathy in TBI is significantly higher than in injuries of similar severity to other areas of the body, or in multiple injuries with TBI. With respect to the association between coagulopathy and PHI, the occurrence of coagulopathy, INR, and PLT was significantly associated with PHI, but APTT and PT were not found to be associated with PHI. In the future, high quality research will be required to further characterize the effects of coagulopathy on TBI and subsequent PHI.

Microfluidics for rapid detection of isocitrate dehydrogenase 1 mutation for intraoperative application.

OBJECT Conventional methods for isocitrate dehydrogenase 1 (IDH1) detection, such as DNA sequencing and immunohistochemistry, are time- and labor-consuming and cannot be applied for intraoperative analysis. To develop a new approach for rapid analysis of IDH1 mutation from tiny tumor samples, this study used microfluidics as a method for IDH1 mutation detection. METHODS Forty-seven glioma tumor samples were used; IDH1 mutation status was investigated by immunohistochemistry and DNA sequencing. The microfluidic device was fabricated from polydimethylsiloxane following standard soft lithography. The immunoanalysis was conducted in the microfluidic chip. Fluorescence images of the on-chip microcolumn taken by the charge-coupled device camera were collected as the analytical results readout. Fluorescence signals were analyzed by NIS-Elements software to gather detailed information about the IDH1 concentration in the tissue samples. RESULTS DNA sequencing identified IDH1 R132H mutation in 33 of 47 tumor samples. The fluorescence signal for IDH1-mutant samples was 5.49 ± 1.87 compared with 3.90 ± 1.33 for wild type (p = 0.005). Thus, microfluidics was capable of distinguishing IDH1-mutant tumor samples from wild-type samples. When the cutoff value was 4.11, the sensitivity of microfluidics was 87.9% and the specificity was 64.3%. CONCLUSIONS This new approach was capable of analyzing IDH1 mutation status of tiny tissue samples within 30 minutes using intraoperative microsampling. This approach might also be applied for rapid pathological diagnosis of diffuse gliomas, thus guiding personalized resection.

Subgroup characteristics of insular low-grade glioma based on clinical and molecular analysis of 42 cases.

Although the classification of insular glioma has been established based on the anatomical location in order to facilitate personalized surgical resection, the diagnosis based on anatomical and functional characteristics becomes more complex when insular tumors extend into either the frontobasal brain region and/or the temporal lobe, as part of the limbic system. Moreover, prognosis of insular tumor resection is still controversial. Further analysis of subgroup characteristics of insular grade II gliomas based on clinical and molecular analysis is required to reliably determine patients' survival rates. In this retrospective study 20 purely insular grade II gliomas patients and 22 paralimbic grade II gliomas that involved frontal and/or temporal lobes were compared with regard to epidemiological and clinical characteristics. The molecular profiles including Isocitrate dehydrogenase 1 (IDH1), telomerase reverse transcriptase (TERT) promoter, and P53 mutations, 1p19q co-deletion were analyzed, and microRNA profiles were assessed by microarray and bioinformatics analysis. Purely insular grade II gliomas displayed a high frequency of IDH1 mutations with favorable outcome. IDH1 mutated paralimbic glioma shared many parameters with the purely insular glioma in respect to growth patterns, survival, and microRNA profile, but differed significantly from the IDH1 wild type paralimbic gliomas. Our findings suggest that IDH1 mutations can define subpopulations of insular gliomas with distinct disease entities regardless of tumor extension patterns. These findings could be useful to develop a customized treatment strategy for insular glioma patients.

TERT promoter mutated WHO grades II and III gliomas are located preferentially in the frontal lobe and avoid the midline.

The promoter region of telomerase reverse transcriptase (TERTp) and isocitrate dehydrogenase (IDH) have been regarded as biomarkers with distinct clinical and phenotypic features. Investigated the possible correlations between tumor location and genetic alterations would enhance our understanding of gliomagenesis and heterogeneity of glioma. We examined mutations of TERTp and IDH by direct sequencing and fluorescence in-situ hybridization in a cohort of 225 grades II and III diffuse gliomas. Correlation analysis between molecular markers and tumor locations was performed by Chi-square tests/Fisher's exact test and multivariate logistic regression analysis. We found gliomas in frontal lobe showed higher frequency of TERTp mutation (P=0.0337) and simultaneously mutations of IDH and TERTp (IDH (mut)-TERTp(mut)) (P=0.0281) than frequency of biomarkers mutation of tumors in no-Frontal lobes, while lower frequency of TERTp mutation (P<0.0001) and simultaneously wild type of IDH and TERTp (IDH (wt)-TERTp(wt)) (P<0.0001) in midline than no-midline lobes. Logistic regression analysis indicated that locations of tumors associated with TERTp mutation (OR=0.540, 95% CI 0.324-0.900, P=0.018) and status of combinations of IDH and TERTp (IDH (mut)-TERTp (mut) vs. IDH (wt)-TERTp (wt) OR=0.162, 95% CI 0.075-0.350, P<0.001). In conclusion, grades II and III gliomas harboring TERTp mutation were located preferentially in the frontal lobe and rarely in midline. Association of IDH-TERTp status and tumor location suggests their potential values in molecular classification of grades II and III gliomas.

Does Early Postsurgical Temozolomide Plus Concomitant Radiochemotherapy Regimen Have Any Benefit in Newly-diagnosed Glioblastoma Patients? A Multi-center, Randomized, Parallel, Open-label, Phase II Clinical Trial.

BACKGROUND: The radiochemotherapy regimen concomitantly employing temozolomide (TMZ) chemotherapy and radiotherapy (RT) 4 weeks after surgery, followed by 6 cycles of TMZ is a common treatment for glioblastoma (GBM). However, its median overall survival (OS) is only 14.6 months. This study was to explore the effectiveness and safety of early TMZ chemotherapy between surgery and chemoradiotherapy plus the standard concomitant radiochemotherapy regimen. METHODS: A randomized, parallel group, open-label study of 99 newly diagnosed GBM patients was conducted at 10 independent Chinese neurosurgical departments from June 2008 to June 2012. Patients were treated with concomitant radiochemotherapy regimen plus early postsurgical temozolomide (early TMZ group) or standard concomitant radiochemotherapy regimen (control group). Overall response was assessed based on objective tumor assessments, administration of corticosteroid and neurological status test. Hematological, biochemical, laboratory, adverse event (AE), and neurological condition were measured for 24 months of follow-up. The primary efficacy endpoint of this study was overall survival (OS). The secondary endpoint was progression free survival (PFS). RESULTS: The median OS time in the early TMZ group was 17.6 months, compared with 13.2 months in the control group (log-rank test P = 0.021). In addition, the OS rate in the early TMZ group was higher at 6, 12, and 18 months than in the control group, respectively (P < 0.05). The median PFS time was 8.7 months in the early TMZ group and 10.4 months in the control group (log-rank test P = 0.695). AEs occurred in 29 (55.8%) and 31(73.8%) patients respectively in early and control groups, including nausea (15.4% vs. 33.3%), vomiting (7.7% vs. 28.6%), fever (7.7% vs. 11.9%), and headache (3.8% vs. 23.8%). Only 30.8% and 33.3% were drug-related, respectively. CONCLUSIONS: Addition of TMZ chemotherapy in the early break of the standard concomitant radiochemotherapy regimen was well tolerated and significantly improved the OS of the GBM patients, compared with standard concomitant radiochemotherapy regimen. However, a larger randomized trial is warranted to verify these results.

TERT promoter mutations contribute to IDH mutations in predicting differential responses to adjuvant therapies in WHO grade II and III diffuse gliomas.

IDH mutations frequently occur in WHO grade II and III diffuse gliomas and have favorable prognosis compared to wild-type tumors. However, whether IDH mutations in WHO grade II and II diffuse gliomas predict enhanced sensitivity to adjuvant radiation (RT) or chemotherapy (CHT) is still being debated. Recent studies have identified recurrent mutations in the promoter region of telomerase reverse transcriptase (TERT) in gliomas. We previously demonstrated that TERT promoter mutations may be promising biomarkers in glioma survival prognostication when combined with IDH mutations. This study analyzed IDH and TERT promoter mutations in 295 WHO grade II and III diffuse gliomas treated with or without adjuvant therapies to explore their impact on the sensitivity of tumors to genotoxic therapies. IDH mutations were found in 216 (73.2%) patients and TERT promoter mutations were found in 112 (38%) patients. In multivariate analysis, IDH mutations (p < 0.001) were independent prognostic factors for PFS and OS in patients receiving genotoxic therapies while TERT promoter mutations were not. In univariate analysis, IDH and TERT promoter mutations were not significant prognostic factors in patients who did not receive genotoxic therapies. Adjuvant RT and CHT were factors independently impacting PFS (RT p = 0.001, CHT p = 0.026) in IDH mutated WHO grade II and III diffuse gliomas but not in IDH wild-type group. Univariate and multivariate analyses demonstrated TERT promoter mutations further stratified IDH wild-type WHO grade II and III diffuse gliomas into two subgroups with different responses to genotoxic therapies. Adjuvant RT and CHT were significant parameters influencing PFS in the IDH wt/TERT mut subgroup (RT p = 0.015, CHT p = 0.015) but not in the IDH wt/TERT wt subgroup. Our data demonstrated that IDH mutated WHO grade II and III diffuse gliomas had better PFS and OS than their IDH wild-type counterparts when genotoxic therapies were administered after surgery. Importantly, we also found that TERT promoter mutations further stratify IDH wild-type WHO grade II and III diffuse gliomas into two subgroups with different responses to adjuvant therapies. Taken together, TERT promoter mutations may predict enhanced sensitivity to genotoxic therapies in IDH wild-type WHO grade II and III diffuse gliomas and may justify intensified treatment in this subgroup.

Gene mutation profiling of primary glioblastoma through multiple tumor biopsy guided by 1H-magnetic resonance spectroscopy.

Genetic mutation has served as the biomarkers for the diagnosis and treatment of glioblastoma multiforme (GBM). However, intra-tumor heterogeneity may interfere with personalized treatment strategies based on mutation analysis. This study aimed to characterize somatic mutation profiling of GBM. We collected 33 samples from 7 patients with the primary GBM associated with different Choline (Cho) to N-acetylaspartate (NAA) index (CNI) through the frameless proton magnetic resonance spectroscopy (1H-MRS) guided biopsies and investigated multiple somatic mutations profiling using the AmpliSeq cancer hotspot panel V2. We identified 53 missense or nonsense mutations in 27 genes including some novel mutations such as APC and IDH2. The mutations in EGFR, TP53, PTEN, PIK3CA genes were presented with different frequency and the majority of the mutated gene was only shared by 1-2 samples from one patient. Moreover, we found the association of CNI with histological grade, but there was no significant change of CNI in the presence of TP53, EGFR and PTEN mutations. These data suggest that gene mutations constitute a heterogeneous marker for primary GBM which may be independent of intra-tumor morphological phenotypes of GBM; therefore, gene mutation markers could not be determined from a small number of needle biopsies or only confined to the high-grade region.

Methods of glioma sample processing for molecular diagnosis for the glioma tissue bank project.

Genome-wide sequencing in glioma samples provides comprehensive insights into oncogenesis and malignant transformation. Several distinct biomarkers have been proven to have clinical significance and are being widely applied in routine clinical practice. Standard sample processing lays the foundation for successful molecular testing. In this study, we found intraoperative neuronavigation ensured higher tumor purity during sample collection, and an automated device helped improve DNA quality and increased yields. These two technologies are beneficial for glioma tissue bank construction and provide for accurate molecular testing during routine clinical practice.

Recurrent gain-of-function USP8 mutations in Cushing's disease.

Cushing's disease, also known as adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (PAs) that cause excess cortisol production, accounts for up to 85% of corticotrophin-dependent Cushing's syndrome cases. However, the genetic alterations in this disease are unclear. Here, we performed whole-exome sequencing of DNA derived from 12 ACTH-secreting PAs and matched blood samples, which revealed three types of somatic mutations in a candidate gene, USP8 (encoding ubiquitin-specific protease 8), exclusively in exon 14 in 8 of 12 ACTH-secreting PAs. We further evaluated somatic USP8 mutations in additional 258 PAs by Sanger sequencing. Targeted sequencing further identified a total of 17 types of USP8 variants in 67 of 108 ACTH-secreting PAs (62.04%). However, none of these mutations was detected in other types of PAs (n = 150). These mutations aggregate within the 14-3-3 binding motif of USP8 and disrupt the interaction between USP8 and 14-3-3 protein, resulting in an elevated capacity to protect EGFR from lysosomal degradation. Accordingly, PAs with mutated USP8 display a higher incidence of EGFR expression, elevated EGFR protein abundance and mRNA expression levels of POMC, which encodes the precursor of ACTH. PAs with mutated USP8 are significantly smaller in size and have higher ACTH production than wild-type PAs. In surgically resected primary USP8-mutated tumor cells, USP8 knockdown or blocking EGFR effectively attenuates ACTH secretion. Taken together, somatic gain-of-function USP8 mutations are common and contribute to ACTH overproduction in Cushing's disease. Inhibition of USP8 or EGFR is promising for treating USP8-mutated corticotrophin adenoma. Our study highlights the potentially functional mutated gene in Cushing's disease and provides insights into the therapeutics of this disease.