Activation of human STING by a molecular glue-like compound.

Stimulator of interferon genes (STING) is a dimeric transmembrane adapter protein that plays a key role in the human innate immune response to infection and has been therapeutically exploited for its antitumor activity. The activation of STING requires its high-order oligomerization, which could be induced by binding of the endogenous ligand, cGAMP, to the cytosolic ligand-binding domain. Here we report the discovery through functional screens of a class of compounds, named NVS-STGs, that activate human STING. Our cryo-EM structures show that NVS-STG2 induces the high-order oligomerization of human STING by binding to a pocket between the transmembrane domains of the neighboring STING dimers, effectively acting as a molecular glue. Our functional assays showed that NVS-STG2 could elicit potent STING-mediated immune responses in cells and antitumor activities in animal models.

Project MED (Medicine, Exposure, and Development): Promoting Access to Healthcare Education for Historically Underrepresented Groups Through Community Engagement, Sustainability, and Technology.

In the U.S., disparities in the healthcare workforce have led to inadequate health outcomes in communities of historically underserved groups. To address the lack of resources and opportunities in health career education for historically underserved group students, Project MED was established. The mission is to expose high school students to the breadth of opportunities in the healthcare field and to prepare students for successful careers in healthcare. Through 3 main pillars-Learn, Lead, and Launch-Project MED has developed a robust repository of 20 workshops, recruited and trained eight mentors, and curated a database of ≥100 opportunities for over 50 students.

OdoriFy: A conglomerate of artificial intelligence-driven prediction engines for olfactory decoding.

The molecular mechanisms of olfaction, or the sense of smell, are relatively underexplored compared with other sensory systems, primarily because of its underlying molecular complexity and the limited availability of dedicated predictive computational tools. Odorant receptors (ORs) allow the detection and discrimination of a myriad of odorant molecules and therefore mediate the first step of the olfactory signaling cascade. To date, odorant (or agonist) information for the majority of these receptors is still unknown, limiting our understanding of their functional relevance in odor-induced behavioral responses. In this study, we introduce OdoriFy, a Web server featuring powerful deep neural network-based prediction engines. OdoriFy enables (1) identification of odorant molecules for wildtype or mutant human ORs (Odor Finder); (2) classification of user-provided chemicals as odorants/nonodorants (Odorant Predictor); (3) identification of responsive ORs for a query odorant (OR Finder); and (4) interaction validation using Odorant-OR Pair Analysis. In addition, OdoriFy provides the rationale behind every prediction it makes by leveraging explainable artificial intelligence. This module highlights the basis of the prediction of odorants/nonodorants at atomic resolution and for the ORs at amino acid levels. A key distinguishing feature of OdoriFy is that it is built on a comprehensive repertoire of manually curated information of human ORs with their known agonists and nonagonists, making it a highly interactive and resource-enriched Web server. Moreover, comparative analysis of OdoriFy predictions with an alternative structure-based ligand interaction method revealed comparable results. OdoriFy is available freely as a web service at https://odorify.ahujalab.iiitd.edu.in/olfy/.

Discovery of a ZIP7 inhibitor from a Notch pathway screen.

The identification of activating mutations in NOTCH1 in 50% of T cell acute lymphoblastic leukemia has generated interest in elucidating how these mutations contribute to oncogenic transformation and in targeting the pathway. A phenotypic screen identified compounds that interfere with trafficking of Notch and induce apoptosis via an endoplasmic reticulum (ER) stress mechanism. Target identification approaches revealed a role for SLC39A7 (ZIP7), a zinc transport family member, in governing Notch trafficking and signaling. Generation and sequencing of a compound-resistant cell line identified a V430E mutation in ZIP7 that confers transferable resistance to the compound NVS-ZP7-4. NVS-ZP7-4 altered zinc in the ER, and an analog of the compound photoaffinity labeled ZIP7 in cells, suggesting a direct interaction between the compound and ZIP7. NVS-ZP7-4 is the first reported chemical tool to probe the impact of modulating ER zinc levels and investigate ZIP7 as a novel druggable node in the Notch pathway.

Impact of Baseline Nutrition and Exercise Status on Toxicity and Outcomes in Phase I and II Oncology Clinical Trial Participants.

BACKGROUND: Malnutrition and physical inactivity are common in patients with advanced cancer and are associated with poor outcomes. There are increasing data that altered body composition is related to the pharmacokinetic properties of cancer therapies. These adverse conditions may impact outcomes in early-phase oncology clinical trials. MATERIALS AND METHODS: We aimed to understand the relationships between baseline nutrition and exercise status with important trial endpoints including treatment-related toxicity and survival. Baseline assessments of nutrition and exercise status were conducted in patients prior to initiation of phase I and II oncology clinical trials. Patients were followed prospectively for the onset of adverse events. Tumor response and survival data were also obtained. Fisher's exact test and chi-square analysis were used to determine statistical significance. Kaplan-Meier curves were used to compare patient duration on study and survival. RESULTS: One hundred patients were recruited, of whom 87 were initiating a phase I trial. Sixty percent were initiating trials studying immunotherapeutic agents. Critical malnutrition was found in 39% of patients, and 52% were sedentary. Patients who were malnourished had significantly increased rates of grade ≥ 3 toxicity (p = .001), hospitalizations (p = .001), and inferior disease control rate (p = .019). Six-month overall survival was significantly reduced in malnourished patients versus nonmalnourished patients (47% vs. 84%; p = .0003), as was median duration on study (48 days vs. 105 days; p = .047). Being sedentary at baseline was associated with decreased duration on study (57 days vs. 105 days; p = .019). CONCLUSION: Malnutrition and sedentary lifestyle are highly prevalent in patients enrolling on early-phase oncology clinical trials and are associated with poor outcomes. The quality of data from these studies may be compromised as a result of these pre-existing conditions. IMPLICATIONS FOR PRACTICE: Phase I and II trials are critical steps in the development of effective cancer therapeutics, yet only a small percentage of agents are ultimately approved for human cancer care. Despite increasing awareness of the interactions between malnutrition, sarcopenia, and treatment-related outcomes such as toxicity and response, these factors are not commonly incorporated into therapeutic decision making at the time of clinical trial consideration. Nutritional status and physical performance may be key biomarkers of mechanisms mediating treatment-related toxicity, dose modifications, risk of hospitalizations, and success of novel agents. This study advocates that a baseline nutritional assessment and early nutritional support may improve tolerability and response to experimental therapies.

In vitro activity of a novel antibacterial agent, levonadifloxacin, against clinical isolates collected in a prospective, multicentre surveillance study in India during 2016-18.

BACKGROUND: Levonadifloxacin is a novel antibiotic belonging to the benzoquinolizine subclass of fluoroquinolones with potent activity against MRSA and quinolone-resistant Staphylococcus aureus. IV levonadifloxacin and its oral prodrug alalevonadifloxacin have recently been approved in India for the treatment of acute bacterial skin and skin structure infections (ABSSSIs) including diabetic foot infections. OBJECTIVES: To investigate the in vitro activity of levonadifloxacin against contemporary clinical isolates collected from multiple tertiary care hospitals across India in the Antimicrobial Susceptibility Profiling of Indian Resistotypes (ASPIRE) surveillance study. METHODS: A total of 1376 clinical isolates, consisting of staphylococci (n = 677), streptococci (n = 178), Enterobacterales (n = 320), Pseudomonas aeruginosa (n = 140) and Acinetobacter baumannii (n = 61), collected (2016-18) from 16 tertiary hospitals located across 12 states in India, were included in the study. The MICs of levonadifloxacin and comparator antibiotics were determined using the reference agar dilution method and broth microdilution method. RESULTS: Levonadifloxacin exhibited potent activity against MSSA (MIC50/90: 0.5/1 mg/L), MRSA (MIC50/90: 0.5/1 mg/L) and levofloxacin-resistant S. aureus (MIC50/90: 1/1 mg/L) isolates. Similarly, potent activity of levonadifloxacin was also observed against CoNS including MDR isolates (MIC50/90: 1/2 mg/L). Against Streptococcus pneumoniae, levonadifloxacin (MIC50/90: 0.5/0.5 mg/L) showed superior activity compared with levofloxacin (MIC50/90: 1/2 mg/L). Among levofloxacin-susceptible Enterobacterales, 80.6% of isolates were inhibited at ≤2 mg/L levonadifloxacin. CONCLUSIONS: Levonadifloxacin displayed potent activity against contemporary MRSA and fluoroquinolone-resistant staphylococcal isolates, thus offering a valuable IV as well as an oral therapeutic option for the treatment of ABSSSIs. Furthermore, levonadifloxacin exhibited a broad-spectrum activity profile as evident from its activity against streptococci and levofloxacin-susceptible Gram-negative isolates.

NCCN Guidelines Insights: Colorectal Cancer Screening, Version 2.2020.

The NCCN Guidelines for Colorectal Cancer (CRC) Screening describe various colorectal screening modalities as well as recommended screening schedules for patients at average or increased risk of developing sporadic CRC. They are intended to aid physicians with clinical decision-making regarding CRC screening for patients without defined genetic syndromes. These NCCN Guidelines Insights focus on select recent updates to the NCCN Guidelines, including a section on primary and secondary CRC prevention, and provide context for the panel's recommendations regarding the age to initiate screening in average risk individuals and follow-up for low-risk adenomas.

The Role of Malnutrition and Muscle Wasting in Advanced Lung Cancer.

PURPOSE OF REVIEW: Malnutrition, cancer cachexia, and sarcopenia often co-occur in patients with advanced cancer and are associated with poorer response to chemotherapy and reduced survival. Here, we evaluate the current literature regarding the role of nutrition and these associated conditions in patients with advanced lung cancer. RECENT FINDINGS: While rates of malnutrition are high, nutritional intervention studies have generally been limited by small sample sizes. Novel strategies such as home-based meal delivery may have promise. While no therapy is approved for cancer cachexia, ghrelin agonists and other targeted therapies have yielded promising data in clinical trials. Recent data also suggest that obesity may improve immunotherapy responsiveness. Malnutrition and associated muscle wasting are clearly negative prognostic markers in advanced lung cancer. Patients with malnutrition should be urgently referred for dietary counseling and guidelines for nutritional support should be followed. Optimal treatment of these syndromes will likely include nutrition and anti-cachexia interventions used in combination.

Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies.

AIM: The aim of this review article is not only to analyze the clinical burden of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care unit (ICU) setting of India, along with the patterns of prevalence and its prevention measures, but also to focus on the new anti-MRSA research molecules which are in late stage of clinical development. BACKGROUND: Methicillin resistance is reported to be present in 13-47% of Staphylococcus aureus infections in India. Therapeutic options to combat MRSA are becoming less, because of emerging resistance to multiple classes of antibiotics. Intensive care units are the harbinger of multidrug-resistant organisms including MRSA and are responsible for its spread within the hospital. The emergence of MRSA in ICUs is associated with poor clinical outcomes, high morbidity, mortality, and escalating treatment costs. There is an urgency to bolster the antibiotic pipeline targeting MRSA. The research efforts for antibiotic development need to match with the pace of emergence of resistance, and new antibiotics are needed to control the impending threat of untreatable MRSA infections. REVIEW RESULTS: Fortunately, several potential antibiotic agents are in the pipeline and the future of MRSA management appears reassuring. CLINICAL SIGNIFICANCE: The authors believe that this knowledge may help form the basis for strategic allocation of current healthcare resources and the future needs. HOW TO CITE THIS ARTICLE: Mehta Y, Hegde A, Pande R, Zirpe KG, Gupta V, Ahdal J, et al. Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies. Indian J Crit Care Med 2020;24(1):55-62.

Improving ethanol yields in sugarcane molasses fermentation by engineering the high osmolarity glycerol pathway while maintaining osmotolerance in Saccharomyces cerevisiae.

The ever-increasing demand of energy has made it imperative to increase the production of renewable fuels like ethanol. Many studies have reported increase in ethanol production by reducing fermentation by-products like glycerol. Deletion of structural genes like gpd1and gpd2 leads to an increase in ethanol by reducing glycerol; however, it makes the yeast osmosensitive that is not desirable for industrial strains. In this study, genes in the HOG pathway which regulates glycerol synthesis in Saccharomyces cerevisiae were targeted for improving ethanol yields in fermentation of sugarcane molasses. Deletion strains of ssk1, hot1, and smp1 were tested and they did not show osmosensitivity. Δssk1 and Δsmp1 recombinant strains showed consistent improved ethanol yields. As a result, a double-deletion strain, Δssk1Δsmp1, was also constructed, which showed a synergistic effect leading to 6% increase in ethanol yield and 35% decrease in glycerol yield. It was also observed that there was a significant decrease in acetic acid yields of all the recombinant strains. Overall, the study demonstrates an industrially viable technique of engineering the HOG pathway resulting in decrease of glycerol and no loss of osmotolerance. These S. cerevisiae strains showed a significant increase in ethanol yields.

Inhibition of Microtubule Depolymerization by Osmolytes.

Microtubule dynamics play a critical role in the normal physiology of eukaryotic cells as well as a number of cancers and neurodegenerative disorders. The polymerization/depolymerization of microtubules is regulated by a variety of stabilizing and destabilizing factors, including microtubule-associated proteins and therapeutic agents (e.g., paclitaxel, nocodazole). Here we describe the ability of the osmolytes polyethylene glycol (PEG) and trimethylamine- N-oxide (TMAO) to inhibit the depolymerization of individual microtubule filaments for extended periods of time (up to 30 days). We further show that PEG stabilizes microtubules against both temperature- and calcium-induced depolymerization. Our results collectively suggest that the observed inhibition may be related to combination of the kosmotropic behavior and excluded volume/osmotic pressure effects associated with PEG and TMAO. Taken together with prior studies, our data suggest that the physiochemical properties of the local environment can regulate microtubule depolymerization and may potentially play an important role in in vivo microtubule dynamics.

Nutrition and Aging: a Practicing Oncologist's Perspective.

Malnutrition is common in patients with cancer and is associated with a variety of negative outcomes. These can include reduced treatment tolerance and worsened cancer prognosis. Various aspects of aging, including sensory, physical, or psychosocial changes, place older patients at a particularly high risk for malnutrition, and these geriatric factors must be identified early and addressed. Despite the lack of available evidence on the optimal nutritional interventions for older adults with cancer, the oncologist must be prepared to address the common nutritional concerns that arise in both advanced cancer and survivorship settings. While BMI, weight loss, and serum albumin are commonly used as surrogates of malnutrition, the use of a comprehensive screening tool may promote early identification of disrupted eating patterns and allow for prompt intervention. New digital technologies have also demonstrated promise to improve nutritional assessment capabilities. Use of conventional nutritional support in conjunction with novel nutraceutical and anti-cachexia approaches may enhance the effectiveness of interventions and improve our ability to reverse malnutrition-associated alterations in body composition. Future geriatric-focused nutrition research will be crucial in helping guide our patients and effectively addressing their dietary and lifestyle concerns.

Rediscovering Chirality - Role of S-Metoprolol in Cardiovascular Disease Management.

BACKGROUND: The process of drug discovery and development today encompass a myriad of paths for bringing a new therapeutic molecule that has minimal adverse effects and of optimal use to the patient. Chirality was proposed in the direction of providing a purer and safer form of drug [Ex- cetrizine and levocetrizine]. Decades have passed since the introduction of this concept and numerous chiral molecules are in existence in therapeutics, yet somehow this concept has been ignored. This review aims to rediscover the ignored facts about chirality, its benefits and clear some common myths considering the example of S-Metoprolol in the management of Hypertension and other cardiovascular diseases. METHODS: Relevant articles from Pubmed, Embase, Medline and Google Scholar were searched using the terms "Chiral", "Chirality", "Enantiomers", "Isomers", "Isomerism", "Stereo-chemistry", and "S-Metoprolol". Out of 103 articles found 17 articles mentioning in general about the concept of chirality and articles on study of S-metoprolol in various cardiovascular diseases were then reviewed. RESULTS: Many articles mention about the importance of chirality yet the concept has not been highlighted much. Clear benefits with chiral molecules have been documented for various drug molecules few amongst them being anaesthetics, antihypertensives, antidepressants. Benefits of S-metoprolol over racemate are also clear in terms of responder rates, dose of administration and adverse effects profile in various cardiovascular diseases. CONCLUSIONS: Chirality is a good way forward in providing a new drug molecule which is safe with lesser pharmacokinetic and pharmacodynamics variability, lesser side effects and more potent action. S-metoprolol is chirally pure form of racemate metoprolol and has lesser side effects, is safer in patients of COPD and Diabetes who also have hypertension and comparable responder rates at half the doses when compared to racemate.

Target identification for a Hedgehog pathway inhibitor reveals the receptor GPR39.

Hedgehog (Hh) signaling determines cell fate during development and can drive tumorigenesis. We performed a screen for new compounds that can impinge on Hh signaling downstream of Smoothened (Smo). A series of cyclohexyl-methyl aminopyrimidine chemotype compounds ('CMAPs') were identified that could block pathway signaling in a Smo-independent manner. In addition to inhibiting Hh signaling, the compounds generated inositol phosphates through an unknown GPCR. Correlation of GPCR mRNA expression levels with compound activity across cell lines suggested the target to be the orphan receptor GPR39. RNA interference or cDNA overexpression of GPR39 demonstrated that the receptor is necessary for compound activity. We propose a model in which CMAPs activate GPR39, which signals to the Gli transcription factors and blocks signaling. In addition to the discovery of GPR39 as a new target that impinges on Hh signaling, we report on small-molecule modulators of the receptor that will enable in vitro interrogation of GPR39 signaling in different cellular contexts.

Examining the influence of specificity ligands and ATP-competitive ligands on the overall effectiveness of bivalent kinase inhibitors.

BACKGROUND: Identifying selective kinase inhibitors remains a major challenge. The design of bivalent inhibitors provides a rational strategy for accessing potent and selective inhibitors. While bivalent kinase inhibitors have been successfully designed, no comprehensive assessment of affinity and selectivity for a series of bivalent inhibitors has been performed. Here, we present an evaluation of the structure activity relationship for bivalent kinase inhibitors targeting ABL1. METHODS: Various SNAPtag constructs bearing different specificity ligands were expressed in vitro. Bivalent inhibitor formation was accomplished by synthesizing individual ATP-competitive kinase inhibitors containing a SNAPtag targeting moiety, enabling the spontaneous self-assembly of the bivalent inhibitor. Assembled bivalent inhibitors were incubated with K562 lysates, and then subjected to affinity enrichment using various ATP-competitive inhibitors immobilized to sepharose beads. Resulting eluents were analyzed using Tandem Mass Tag (TMT) labeling and two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS). Relative binding affinity of the bivalent inhibitor was determined by calculating the concentration at which 50% of a given kinase remained bound to the affinity matrix. RESULTS: The profiling of three parental ATP-competitive inhibitors and nine SNAPtag conjugates led to the identification of 349 kinase proteins. In all cases, the bivalent inhibitors exhibited enhanced binding affinity and selectivity for ABL1 when compared to the parental compound conjugated to SNAPtag alone. While the rank order of binding affinity could be predicted by considering the binding affinities of the individual specificity ligands, the resulting affinity of the assembled bivalent inhibitor was not predictable. The results from this study suggest that as the potency of the ATP-competitive ligand increases, the contribution of the specificity ligand towards the overall binding affinity of the bivalent inhibitor decreases. However, the affinity of the specificity components in its interaction with the target is essential for achieving selectivity. CONCLUSION: Through comprehensive chemical proteomic profiling, this work provides the first insight into the influence of ATP-competitive and specificity ligands binding to their intended target on a proteome-wide scale. The resulting data suggest a subtle interplay between the ATP-competitive and specificity ligands that cannot be accounted for by considering the specificity or affinity of the individual components alone.

The Relevance of Hereditary Cancer Risks to Precision Oncology: What Should Providers Consider When Conducting Tumor Genomic Profiling?

Through tumor genomic profiling (TGP), existing and novel treatments can be selected to better target the specific dysregulated molecular pathways that drive growth and spread of a patient's tumor. Although the primary purpose of TGP is to detect targetable somatic mutations for treatment, TGP may also uncover germline mutations with important implications for patients and family members. Oncology care providers should be aware of the hereditary cancer risks associated with genes commonly tested by TGP. Further, patients should be informed about the possible discovery of hereditary cancer risk information and the relevance of this information to their health and that of family members, and should have their preferences toward further evaluation of hereditary risk information that could be revealed by TGP documented in the medical record and followed.

Clinical studies examining the impact of obesity on breast cancer risk and prognosis.

Obesity is associated with an increased risk of breast cancer, and increased risk of recurrence in women who develop breast cancer. Evidence suggests that the risk of estrogen-receptor (ER)-positive breast cancer is increased in obese postmenopausal women, whereas in premenopausal women the risk of triple negative breast cancer is increased. Nonetheless, the presence of obesity at diagnosis, and possibly weight gain after diagnosis, may independently contribute to an individual's risk of recurrence of both pre- and postmenopausal breast cancer. Factors associated with adiposity that are likely contributing factors include hyperinsulinemia, inflammation, and relative hyperestrogenemia. Some studies suggest that some aromatase inhibitors may be less effective in obese women than lean women. Clinical trials have evaluated pharmacologic (eg, metformin) and dietary/lifestyle interventions to reduce breast cancer recurrence, although these interventions have not been tested in obese women who may be most likely to benefit from them. Further research is required in order to identify adiposity-associated factors driving recurrence, and design clinical trials to specifically test interventions in obese women at highest risk of recurrence.

Heterologous production of (-)-geosmin in Saccharomyces cerevisiae.

(-)-Geosmin has high demand in perfumes and cosmetic products for its earthy congenial aroma. The current production of (-)-geosmin is either by distillation of sun-baked soil or by inefficient chemical synthesis because of the presence of multiple chiral centers. Fermentation processes are not viable as the titers of the Streptomyces sp. based processes are low. This work presents an alternative route by the heterologous synthesis of (-)-geosmin in Saccharomyces cerevisiae. The enzyme involved is the bifunctional geosmin synthase that catalyzes the conversion of farnesyl diphosphate to germacradienol and germacradienol to geosmin. This study evaluated the activity of many orthologs of geosmin synthase when expressed heterologously in S. cerevisiae. When the well-characterized CAB41566 from Streptomyces coelicolor origin was tested, germacradienol and germacrene D were detected but no geosmin. Bioinformatic analysis based on high/low identities to N-terminal and C-terminal domains of CAB41566 was carried out to identify different orthologs of geosmin synthase proteins from different bacterial and fungal origins. ADO68918 of Stigmatella aurantiaca origin showed the best activity among the tested orthologs, not only in terms of geosmin production but also an order of magnitude higher total abundance of the products of geosmin synthase as compared to CAB41566. This study successfully demonstrated the production of (-)-geosmin in S. cerevisiae and offers an alternative, sustainable and environment-friendly approach to producing (-)-geosmin.

Food Insecurity and Dietary Quality in African American Patients with Gastrointestinal Cancers: An Exploratory Study.

African American (AA) individuals experience food insecurity at twice the rate of the general population. However, few patients are screened for these measures in the oncology setting. The primary aim of this study was to evaluate associations between food insecurity and dietary quality in AA patients with gastrointestinal (GI) malignancies. The secondary aim was to evaluate differences in dietary quality and the level of food insecurity between the participants at Temple University Hospital (TUH) vs. Fox Chase Cancer Center (FCCC). A single-arm, cross-sectional study was conducted, in which 40 AA patients with GI malignancies were recruited at FCCC and TUH between February 2021 and July 2021. Participants completed the US Adult Food Security Survey Module to assess the level of food security (food secure vs. food insecure). An electronic food frequency questionnaire (VioScreenTM) was administered to obtain usual dietary intake. Diet quality was calculated using the Healthy Eating Index 2015 (HEI-2015). Dietary quality and food insecurity were summarized using standard statistical measures. Overall, 6 of the 40 participants (15%) reported food insecurity, and the mean HEI-2015 score was 64.2. No association was observed between dietary quality and food insecurity (p = 0.29). However, we noted that dietary quality was significantly lower among patients presenting at TUH (mean HEI-2015 = 57.8) compared to patients at FCCC (mean HEI-2015 = 73.5) (p < 0.01). Food insecurity scores were also significantly higher in the TUH population vs. the FCCC population (p < 0.01).

Extent of resection and progression-free survival in vestibular schwannoma: a volumetric analysis.

OBJECTIVE: To preserve facial nerve function in vestibular schwannoma (VS) microsurgery, some have advocated subtotal resection (STR) if the tumor is densely adherent to a thinned facial nerve. The objective of this study was to determine if residual volume is associated with progression and whether there is a threshold residual volume that should be pursued during STR to prevent recurrence. A secondary objective of this study was to determine whether facial nerve function at last follow-up was associated with extent of resection (EOR). METHODS: Clinical and radiographic data were retrospectively collected from the records of 164 patients with VS who underwent resection. Tumor volumes were measured using Visage, and standard statistical methods were used. The House-Brackmann scale was used to assess changes in facial nerve function before surgery and at last follow-up. RESULTS: Sixty-one patients (37%) received gross-total resection (GTR) and 103 (63%) received STR. The median clinical and radiographic follow-ups were 49 and 48 months, respectively. The median residual volume was 0.5 cm3 after STR. Kaplan-Meier actuarial survival analysis revealed a 96.3% 5-year progression-free survival (PFS) rate after GTR, which was greater than that after STR (84.5%, p = 0.03). Recursive partitioning analysis of patients receiving STR revealed a residual volume of 0.60 cm3 as the optimal threshold for recurrence. Patients with residual volume ≥ 0.60 cm3 had a 76.0% 5-year PFS, regardless of adjuvant SRS, which was lower than that for patients undergoing GTR (96.3%) or STR (95.6%) with residual volumes < 0.60 cm3 (p < 0.01). On Cox regression analysis, residual volume ≥ 0.60 cm3 (HR 14.4, p = 0.01) was independently associated with progression, even when accounting for patient age, adjuvant radiosurgery, and preoperative tumor size. In 112 patients with at least 24 months of follow-up after their last treatment, tumor control was achieved in 111 (99.1%) patients at a median last follow-up of 71 months. Worse facial nerve function at the last follow-up was independently associated with prior treatment for VS (adjusted OR 3.7, p = 0.04), but not residual volume cohort or preoperative tumor volume. CONCLUSIONS: Residual volume > 0.60 cm3 after VS resection was independently associated with tumor progression, even accounting for adjuvant SRS. These data support maximizing the EOR during VS surgery, even if GTR cannot be safely achieved.