SEQUENTIAL PARS PLANA VITRECTOMY AND INVERTED INTERNAL LIMITING MEMBRANE FLAP TECHNIQUE FOR RHEGMATOGENOUS RETINAL DETACHMENTS WITH PERIPHERAL BREAKS AND CONCOMITANT NONCAUSATIVE MACULAR HOLE IN NONHIGHLY MYOPIC PATIENTS.

PURPOSE: To present the anatomical and functional results of sequential pars plana vitrectomy for treating rhegmatogenous retinal detachment with peripheral breaks and concomitant noncausative macular holes (MHs) in nonhighly myopic patients. METHODS: Medical records of patients who underwent rhegmatogenous retinal detachment surgical repair between 2017 and 2023 were reviewed. Of 980 patients with rhegmatogenous retinal detachment, 10 had concurrent MH and underwent sequential pars plana vitrectomy for rhegmatogenous retinal detachment repair and air endotamponade, followed by MH repair using the inverted internal limiting membrane flap technique and C2F6 endotamponade after a minimum of 1 week. The main outcomes measured were best-corrected visual acuity change, retinal reattachment rate, MH closure rate, and closure type. RESULTS: The retinal reattachment rate was 90% after the primary surgery and 100% after subsequent surgery. Macular hole closure was achieved in all cases. Macular hole diameters ranged from 291 to 702 µm. Anatomical recovery showed mainly 1A closure types (90%). Functional recovery demonstrated significant best-corrected visual acuity improvement, with a mean visual acuity gain of 1.58 ± 0.41 the logarithm of the minimum angle of resolution. CONCLUSION: For this infrequent pathology, sequential surgery using the inverted internal limiting membrane flap technique and air/gas endotamponade yielded favorable anatomical and functional outcomes. This controlled and standardized approach using sequential surgeries contributes to the achievement of consistent results.

Corneal Epithelial Changes in Diabetic Patients: A Review.

The relationship between diabetes mellitus and ocular complications has been extensively studied by many authors. Diabetic keratopathy has already been well characterized and defined as a clinical entity. This review focuses on exploring corneal epithelial changes in diabetic patients, aiming to provide a pragmatic overview of the existing knowledge on this topic. The paper systematically examines alterations in corneal epithelial structure and their impact on diabetic patients. Advanced imaging techniques are also discussed for their role in precise characterization and improved diagnostics. Additionally, the paper explores the mechanisms behind corneal epithelial changes in diabetes, looking at factors such as hyperglycemia, oxidative stress, and Advanced Glycation End-Products. The impact of altered corneal epithelial integrity on barrier function and susceptibility to external issues is considered, addressing potential links to heightened proteolytic enzyme activities and delayed wound healing observed in diabetic individuals. The review also covers the practical implications of corneal epithelial changes, including the association with corneal erosions, persistent epithelial defects, and an increased risk of dry eye syndrome in diabetic patients.

Accurate Identification of Subclones in Tumor Genomes.

Understanding intratumor heterogeneity is critical for studying tumorigenesis and designing personalized treatments. To decompose the mixed cell population in a tumor, subclones are inferred computationally based on variant allele frequency (VAF) from bulk sequencing data. In this study, we showed that sequencing depth, mean VAF, and variance of VAF of a subclone are confounded. Without considering this effect, current methods require deep-sequencing data (>300× depth) to reliably infer subclones. Here, we present a novel algorithm that incorporates depth-variance and mean-variance dependencies in a clustering error model and successfully identifies subclones in tumors sequenced at depths of as low as 30×. We implemented the algorithm as a model-based adaptive grouping of subclones (MAGOS) method. Analyses of computer simulated data and empirical sequencing data showed that MAGOS outperformed existing methods on minimum sequencing depth, decomposition accuracy, and computation efficiency. The most prominent improvements were observed in analyzing tumors sequenced at depths between 30× and 200×, whereas the performance was comparable between MAGOS and existing methods on deeply sequenced tumors. MAGOS supports analysis of single-nucleotide variants and copy number variants from a single sample or multiple samples of a tumor. We applied MAGOS to whole-exome data of late-stage liver cancers and discovered that high subclone count in a tumor was a significant risk factor of poor prognosis. Lastly, our analysis suggested that sequencing multiple samples of the same tumor at standard depth is more cost-effective and robust for subclone characterization than deep sequencing a single sample. MAGOS is available at github (https://github.com/liliulab/magos).

Family Rank: a graphical domain knowledge informed feature ranking algorithm.

MOTIVATION: When designing prediction models built with many features and relatively small sample sizes, feature selection methods often overfit training data, leading to selection of irrelevant features. One way to potentially mitigate overfitting is to incorporate domain knowledge during feature selection. Here, a feature ranking algorithm called 'Family Rank' is presented in which features are ranked based on a combination of graphical domain knowledge and feature scores computed from empirical data. RESULTS: A simulated dataset is used to demonstrate a scenario in which family rank outperforms other state-of-the-art graph based ranking algorithms, decreasing the sample size needed to detect true predictors by 2- to 3-fold. An example from oncology is then used to explore a real-world application of family rank. AVAILABILITY AND IMPLEMENTATION: An implementation of Family Rank is freely available at https://cran.r-project.org/package=FamilyRank. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Prematurity-Risk Factor or Coincidence in Congenital Glaucoma?

Background and Objective: To correlate the intraocular pressure with the postconceptional age and identify a statistically significant connection between congenital glaucoma and prematurity. Materials and Methods: The current paper is a retrospective, comparative, case-control study. Data collection featured maternal age, gestational age at birth, birth weight, and intraocular ocular pressure (IOP) measurements. Results: Forty-two eyes of 21 children underwent examination. The participants were assigned into two groups. The Preterm-Glaucoma (PG) group included eight preterm-born children diagnosed with glaucoma, whereas the Preterm (P) group was comprised of premature newborns without the aforementioned condition. There was no statistically relevant difference in birth weight (p = 0.691078) nor in mean gestational age (p = 0.752623) between the two groups. The mean IOP in the PG group was 23.813 ± 4.5493, whereas in the P group, it ranged around 13.231 ± 1.0699, p < 0.0001. Using mixed-effects models, we obtained a reduction in IOP of 0.45 mmHg per week in the first month of life. A further weekly reduction of 0.36 mmHg was achieved in the next two months. Conclusions: The mean IOP of prematurely born children decreased with age. Our findings correlate with previously conducted studies, however, the drop in IOP values exceeded any data published so far. We found no correlation between prematurity and the incidence of congenital glaucoma.

Exome Sequencing of Two Siblings with Sporadic Autism Spectrum Disorder and Severe Speech Sound Disorder Suggests Pleiotropic and Complex Effects.

Recent studies of autism spectrum disorder (ASD) and childhood apraxia of speech (CAS) have resulted in conflicting conclusions regarding the comorbidity of these disorders on phenotypic grounds. In a nuclear family with two dually affected and one unaffected offspring, whole-exome sequences were evaluated for single nucleotide and indel variants and CNVs. The affected siblings but not the unaffected sibling share a rare deleterious compound heterozygous mutation in WWOX, implicated both in ASD and motor control. In addition, one of the affected children carries a rare deleterious de novo mutation in the ASD candidate gene RIMS1. The two affected children but not their unaffected sibling inherited deleterious variants with relevance for ASD and/or CAS. WWOX, RIMS1, and several of the genes harboring the inherited variants are expressed in the brain during prenatal and early postnatal development. Results suggest compound heterozygosity as a cause of ASD and CAS, pleiotropic gene effects, and potentially additional, complex genetic effects.

An update on the management and outcomes of cancer patients with severe aortic stenosis.

OBJECTIVES: We compared the outcomes of aortic valve replacement (AVR) by transcatheter (TAVR) and surgical (SAVR) routes with those of optimal medical management in patients with cancer and severe aortic stenosis (AS). BACKGROUND: Cancer therapy requires optimal cardiac output; however, the treatment of AS in cancer patients is not established. METHODS: Cancer patients with severe AS during January 2009 through February 2018 at a large cancer center were identified. Demographic and clinical characteristics including previous or active cancer diagnosis, history of chest radiotherapy, AS treatment, and survival were collected. Univariate Cox proportional hazards regression, the Kaplan-Meier analysis, and log-rank tests were used to compare overall survival (OS) between AS treatment groups. RESULTS: Sixty-five cancer patients with severe AS were identified; 28 received optimal medical treatment alone, 30 received TAVR, and seven received SAVR. The patients were predominantly male (n = 44, 68%) with a mean age of 71.17 years. The median OS was 9.87 months, and the most common cause of death was cancer (n = 29, 94% of deaths). AVR was associated with a lower risk of death than no AVR (hazard ratio [HR] 0.38, P = 0.007), and patients who underwent TAVR (HR 0.36, P = 0.01) had better survival than those with no AVR. Malignancy type, stage, and treatment were not associated with OS. CONCLUSIONS: Patients with cancer and severe AS who underwent AVR, predominantly TAVR, experienced better survival than those who had no AVR regardless of cancer type or cancer treatment. TAVR may be considered in patients with cancer and AS.

The Onco-cardiologist Dilemma: to Implant, to Defer, or to Avoid Transcatheter Aortic Valve Replacement in Cancer Patients with Aortic Stenosis?

PURPOSE OF REVIEW: Aging is associated with an increased prevalence of both cancer and heart disease. The progression of aortic valve calcification to aortic stenosis may be accelerated by both cardiovascular risk factors and cancer treatments, such as radiotherapy with mediastinal involvement. Symptomatic aortic stenosis is occasionally diagnosed in cancer patients undergoing cardiovascular evaluation; likewise, cancer is often recognized during assessment preceding aortic valve interventions. In these complex cases, physicians face difficult treatment decisions. Due to a myriad of clinical presentations of cancer and valve disease, specific guidelines for this patient population are not currently in place. Management is currently based on clinical judgment, on an individual basis. RECENT FINDINGS: Patients with cancer in remission or with a favorable prognosis should be treated according to current cardiovascular guidelines. In these patients, aortic valve replacement can be performed either by surgery or transcatheter. Significant challenges arise in patients with active cancer, especially those receiving anti-cancer treatment. Recent data suggests that these patients can be offered aortic valve replacement, with a trend of favoring the transcatheter route in order to minimize perioperative risk and complications associated with major surgery. Patients with advanced cancer and severe aortic stenosis should be offered palliative care and can benefit from aortic balloon valvuloplasty if indicated. Modern cancer treatments associated with improved long-term prognosis may allow the appropriate cure of aortic stenosis. We discuss the protocol, outcomes, and evolving recommendations of aortic valve replacement in cancer patients with aortic stenosis.

miR2Pathway: A novel analytical method to discover MicroRNA-mediated dysregulated pathways involved in hepatocellular carcinoma.

MicroRNAs (miRNAs) are small, non-coding RNAs involved in the regulation of gene expression at a post-transcriptional level. Recent studies have shown miRNAs as key regulators of a variety of biological processes, such as proliferation, differentiation, apoptosis, metabolism, etc. Aberrantly expressed miRNAs influence individual gene expression level, but rewired miRNA-mRNA connections can influence the activity of biological pathways. Here, we define rewired miRNA-mRNA connections as the differential (rewiring) effects on the activity of biological pathways between hepatocellular carcinoma (HCC) and normal phenotypes. Our work presented here uses a PageRank-based approach to measure the degree of miRNA-mediated dysregulation of biological pathways between HCC and normal samples based on rewired miRNA-mRNA connections. In our study, we regard the degree of miRNA-mediated dysregulation of biological pathways as disease risk of biological pathways. Therefore, we propose a new method, miR2Pathway, to measure and rank the degree of miRNA-mediated dysregulation of biological pathways by measuring the total differential influence of miRNAs on the activity of pathways between HCC and normal states. miR2Pathway proposed here systematically shows the first evidence for a mechanism of biological pathways being dysregulated by rewired miRNA-mRNA connections, and provides new insight into exploring mechanisms behind HCC. Thus, miR2Pathway is a novel method to identify and rank miRNA-dysregulated pathways in HCC.

BitTorious volunteer: server-side extensions for centrally-managed volunteer storage in BitTorrent swarms.

BACKGROUND: Our publication of the BitTorious portal [1] demonstrated the ability to create a privatized distributed data warehouse of sufficient magnitude for real-world bioinformatics studies using minimal changes to the standard BitTorrent tracker protocol. In this second phase, we release a new server-side specification to accept anonymous philantropic storage donations by the general public, wherein a small portion of each user's local disk may be used for archival of scientific data. We have implementated the server-side announcement and control portions of this BitTorrent extension into v3.0.0 of the BitTorious portal, upon which compatible clients may be built. RESULTS: Automated test cases for the BitTorious Volunteer extensions have been added to the portal's v3.0.0 release, supporting validation of the "peer affinity" concept and announcement protocol introduced by this specification. Additionally, a separate reference implementation of affinity calculation has been provided in C++ for informaticians wishing to integrate into libtorrent-based projects. CONCLUSIONS: The BitTorrent "affinity" extensions as provided in the BitTorious portal reference implementation allow data publishers to crowdsource the extreme storage prerequisites for research in "big data" fields. With sufficient awareness and adoption of BitTorious Volunteer-based clients by the general public, the BitTorious portal may be able to provide peta-scale storage resources to the scientific community at relatively insignificant financial cost.

AMASS: a database for investigating protein structures.

MOTIVATION: Modern techniques have produced many sequence annotation databases and protein structure portals, but these Web resources are rarely integrated in ways that permit straightforward exploration of protein functional residues and their co-localization. RESULTS: We have created the AMASS database, which maps 1D sequence annotation databases to 3D protein structures with an intuitive visualization interface. Our platform also provides an analysis service that screens mass spectrometry sequence data for post-translational modifications that reside in functionally relevant locations within protein structures. The system is built on the premise that functional residues such as active sites, cancer mutations and post-translational modifications within proteins may co-localize and share common functions. AVAILABILITY AND IMPLEMENTATION: AMASS database is implemented with Biopython and Apache as a freely available Web server at amass-db.org.

The Biological Reference Repository (BioR): a rapid and flexible system for genomics annotation.

MOTIVATION: The Biological Reference Repository (BioR) is a toolkit for annotating variants. BioR stores public and user-specific annotation sources in indexed JSON-encoded flat files (catalogs). The BioR toolkit provides the functionality to combine and retrieve annotation from these catalogs via the command-line interface. Several catalogs from commonly used annotation sources and instructions for creating user-specific catalogs are provided. Commands from the toolkit can be combined with other UNIX commands for advanced annotation processing. We also provide instructions for the development of custom annotation pipelines. AVAILABILITY AND IMPLEMENTATION: The package is implemented in Java and makes use of external tools written in Java and Perl. The toolkit can be executed on Mac OS X 10.5 and above or any Linux distribution. The BioR application, quickstart, and user guide documents and many biological examples are available at http://bioinformaticstools.mayo.edu.

BitTorious: global controlled genomics data publication, research and archiving via BitTorrent extensions.

BACKGROUND: Centralized silos of genomic data are architecturally easier to initially design, develop and deploy than distributed models. However, as interoperability pains in EHR/EMR, HIE and other collaboration-centric life sciences domains have taught us, the core challenge of networking genomics systems is not in the construction of individual silos, but the interoperability of those deployments in a manner embracing the heterogeneous needs, terms and infrastructure of collaborating parties. This article demonstrates the adaptation of BitTorrent to private collaboration networks in an authenticated, authorized and encrypted manner while retaining the same characteristics of standard BitTorrent. RESULTS: The BitTorious portal was sucessfully used to manage many concurrent domestic Bittorrent clients across the United States: exchanging genomics data payloads in excess of 500GiB using the uTorrent client software on Linux, OSX and Windows platforms. Individual nodes were sporadically interrupted to verify the resilience of the system to outages of a single client node as well as recovery of nodes resuming operation on intermittent Internet connections. CONCLUSIONS: The authorization-based extension of Bittorrent and accompanying BitTorious reference tracker and user management web portal provide a free, standards-based, general purpose and extensible data distribution system for large 'omics collaborations.

Differential expression of microRNAs as predictors of glioblastoma phenotypes.

BACKGROUND: Glioblastoma is the most aggressive primary central nervous tumor and carries a very poor prognosis. Invasion precludes effective treatment and virtually assures tumor recurrence. In the current study, we applied analytical and bioinformatics approaches to identify a set of microRNAs (miRs) from several different human glioblastoma cell lines that exhibit significant differential expression between migratory (edge) and migration-restricted (core) cell populations. The hypothesis of the study is that differential expression of miRs provides an epigenetic mechanism to drive cell migration and invasion. RESULTS: Our research data comprise gene expression values for a set of 805 human miRs collected from matched pairs of migratory and migration-restricted cell populations from seven different glioblastoma cell lines. We identified 62 down-regulated and 2 up-regulated miRs that exhibit significant differential expression in the migratory (edge) cell population compared to matched migration-restricted (core) cells. We then conducted target prediction and pathway enrichment analysis with these miRs to investigate potential associated gene and pathway targets. Several miRs in the list appear to directly target apoptosis related genes. The analysis identifies a set of genes that are predicted by 3 different algorithms, further emphasizing the potential validity of these miRs to promote glioblastoma. CONCLUSIONS: The results of this study identify a set of miRs with potential for decreased expression in invasive glioblastoma cells. The verification of these miRs and their associated targeted proteins provides new insights for further investigation into therapeutic interventions. The methodological approaches employed here could be applied to the study of other diseases to provide biomedical researchers and clinicians with increased opportunities for therapeutic interventions.

Expression of Hormones' Receptors in Human Corneal Endothelium from Fuchs' Dystrophy: A Possible Gender' Association.

Background: Age and sex are the most significant risk of factors for advanced Fuchs dystrophy. Nevertheless, few data are available on the hormone's receptor pattern expressed in adult and advanced fuchs endothelial corneal dystrophy (FECD). We investigated the impact of gender, growth factors and extracellular matrix (ECM) regulatory proteins expressed by the dystrophic endothelia. Methods: Ten dystrophic endothelial tissues and 10 normal endothelial sheets (corneoscleral specimens; Eye Bank) were used for this characterization study. Hormones' receptors (ERα, AR, PR, SHBG), few growth factors (VEGFA, ßNGF, TGFß1), some ECM regulators (MMP1, MMP7) and few inflammatory cytokines (IFNγ, IL10) were analyzed by real-time RT-PCR. Results: ERα transcripts were significantly increased, AR and SHBG transcripts were decreased in Fuchs endothelia from female patients, and no changes were detected for PR transcripts. VEGFA, ßNGF and TGFß1 transcripts were upregulated in Fuchs' endothelia, but not significantly linked to gender. High MMP1 and low MMP7 transcripts' expression were detected in Fuchs' specimens, mainly in males than females. An increased IFNγ (Th1) transcript expression was observed in females than males, and a trend to increase for IL10 (Th2) transcripts was detected in males than females. Conclusions: Our findings clearly indicate that hormone receptors, growth factors and matrix mediators as well as a Th1 pathway are predominant in Fuchs' dystrophy, displaying a pattern of expression specific for the female phenotype. The differential expression of hormones' receptors and the Th1/Th2 ratio might prompt to new theories to be tested in vitro and in vivo models, such as the use of hormonal substitute for counteracting this endothelial cell lost.

Joint exome and metabolome analysis in individuals with dyslexia: Evidence for associated dysregulations of olfactory perception and autoimmune functions.

Dyslexia is a learning disability that negatively affects reading, writing, and spelling development at the word level in 5%-9% of children. The phenotype is variable and complex, involving several potential cognitive and physical concomitants such as sensory dysregulation and immunodeficiencies. The biological pathogenesis is not well-understood. Toward a better understanding of the biological drivers of dyslexia, we conducted the first joint exome and metabolome investigation in a pilot sample of 30 participants with dyslexia and 13 controls. In this analysis, eight metabolites of interest emerged (pyridoxine, kynurenic acid, citraconic acid, phosphocreatine, hippuric acid, xylitol, 2-deoxyuridine, and acetylcysteine). A metabolite-metabolite interaction analysis identified Krebs cycle intermediates that may be implicated in the development of dyslexia. Gene ontology analysis based on exome variants resulted in several pathways of interest, including the sensory perception of smell (olfactory) and immune system-related responses. In the joint exome and metabolite analysis, the olfactory transduction pathway emerged as the primary pathway of interest. Although the olfactory transduction and Krebs cycle pathways have not previously been described in dyslexia literature, these pathways have been implicated in other neurodevelopmental disorders including autism spectrum disorder and obsessive-compulsive disorder, suggesting the possibility of these pathways playing a role in dyslexia as well. Immune system response pathways, on the other hand, have been implicated in both dyslexia and other neurodevelopmental disorders.

Repeatability of Automatic Measurements by an Anterior Segment Swept-Source OCT Biometer in Patients With Keratoconus.

PURPOSE: To evaluate the repeatability of automatic measurements of a new anterior segment optical coherence tomographer (ANTERION; Heidelberg Engineering) and their agreement with an anterior segment optical coherence tomography device combined with Placido disc corneal topography (MS-39; CSO) in patients affected by keratoconus. METHODS: Fifty-four consecutive patients were included. Three measurements were performed with the ANTERION and one with the MS-39. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Agreement was investigated with the 95% limits of agreement. The paired t-test and Wilcoxon matched-pairs test were performed to compare the measurements of the different devices. RESULTS: Repeatability of ANTERION measurements was high, with an ICC greater than 0.98 for all parameters. Many parameters revealed a CoV of less than 1% and a CoV within 5% was obtained for astigmatism measurements. The ANTERION measured a significantly higher corneal power and the MS-39 more negative posterior keratometric values. These differences were mirrored by a moderate agreement for mean simulated keratometry and poor agreement for total corneal power and posterior keratometry. CONCLUSIONS: The ANTERION revealed high repeatability of automatic measurements and good agreement with the MS-39 for many parameters in patients affected by keratoconus, but for most parameters the two instruments cannot be considered interchangeable. [J Refract Surg. 2024;40(7):e445-e452.].

Diagnostic Performance of Diastolic Hyperemia-Free Ratio Compared With Invasive Fractional Flow Reserve for Evaluation of Coronary Artery Disease.

Hyperemic and nonhyperemic pressure ratios are frequently used to assess the hemodynamic significance of coronary artery disease and to guide the need for myocardial revascularization. However, there are limited data on the diagnostic performance of the diastolic hyperemia-free ratio (DFR). We evaluated the diagnostic performance of the DFR compared with invasive fractional flow reserve (FFR). We performed a prospective, single-center study of 308 patients (343 lesions) who underwent DFR and FFR for evaluation of visually estimated 40% to 90% stenoses. Diagnostic performance of the DFR compared with FFR was evaluated using linear regression, Bland-Altman analysis, and receiver operating characteristic curves. The overall diagnostic accuracy of the DFR was 83%; the accuracy rates were 86%, 40%, and 95% when the DFR was <0.86, 0.88 to 0.90, and >0.93, respectively. The sensitivity, specificity, positive predicative value, and negative predictive value were 60%, 91%, 71%, and 87%, respectively. The Pearson correlation coefficient was 0.75 (p <0.05). The Bland-Altman analysis showed a mean difference of 0.09, and the area under the receiver operating characteristic curve was 0.88 (95% confidence interval 0.84 to 0.92, p <0.05). In conclusion, the DFR has a good diagnostic performance compared with FFR but 17% of the measurements were discordant. The diagnostic accuracy of the DFR was only 40% when the DFR was 0.88 to 0.90, suggesting that FFR may be useful in these arteries.

Idiopathic Subglottic Stenosis Is Associated With More Frequent and Abnormal Squamous Metaplasia.

OBJECTIVES: Gain insights into the pathophysiology of idiopathic subglottic stenosis (iSGS) by investigating differences in transcriptome of subglottic mucosal tissue between patients with iSGS and controls, and between tracheal and subglottic tissue within patients. METHODS: RNA sequencing was conducted on biopsied mucosal samples collected from subglottic and tracheal (in-patient control) regions in iSGS patients, and from subglottis in controls. The gene expression differences were validated on a protein level by (1) staining the tissue samples obtained from a second cohort of patients and controls; and (2) in vitro functional assays using primary subglottic epithelial cells from both iSGS patients and healthy donors. RESULTS: We found 7 upregulated genes in the subglottic region of iSGS patients relative to both the tracheal mucosa and subglottic region of controls. A gene ontology enrichment analysis found that the epithelial cell differentiation and cornification pathways are significant, involving specifically 3 of the genes: involucrin (IVL), small proline rich protein 1B (SPRR1B), and keratin 16 (KRT16). Involvement of these pathways suggests squamous metaplasia of the epithelium. Histological analyses of epithelium in subglottic mucosal biopsies revealed squamous metaplasia in 41% of the samples from iSGS patients and in 25% from controls. Immunohistochemical evaluation of the samples presented with squamous epithelium revealed increased expression of the protein encoded by SPRR1B, hyperproliferative basal cells, shedding of apical layers, and accompanying lesions in iSGS compared to CTRL. Cultured primary subglottic epithelial cells from iSGS patients had higher proliferation rates compared to healthy donors and squamous metaplastic differentiation formed thinner epithelia with increased expression proteins encoded by INV, SPRR1B, and KRT16, suggesting intrinsic dysfunction of basal cells in iSGS. CONCLUSIONS: Abnormal squamous differentiation of epithelial cells may contribute to the pathogenesis of iSGS. Patients having metaplastic epithelial phenotype may be sensitive to drugs that reverse it to a normal phenotype.