Variant Subtype Research Articles

Overview of histologic variants of urothelial carcinoma: current trends and narrative review on treatment outcomes.

Background and ObjectiveThe histologic variants of urothelial carcinoma (UC) are tumors arising from within the urothelium in which some component of the tumor morphology is other than urothelial. They are underdiagnosed, aggressive and have varying pathologic response rates to systemic chemotherapy. There are no consensus guidelines on the use of systemic chemotherapy in variant histology (VH) of UC. We performed a contemporary review on pathologic response rates to neoadjuvant systemic therapy and survival outcomes following radical cystectomy in order to provide a rationale for clinical practice recommendations on the management of UC with VH.MethodsA PubMed literature search was conducted for all English articles from inception reporting either pathological response rates to neoadjuvant treatment or survival outcomes after radical cystectomy in non-metastatic VH of UC.Key Content and FindingsNeoadjuvant chemotherapy (NAC) prior to radical cystectomy was shown to be a beneficial treatment strategy in UC with VH. The micropapillary, plasmacytoid, nested and sarcomatoid histologic variants were associated with worse survival outcomes compared to conventional UC and UC with squamous or glandular differentiation despite initial downstaging with chemotherapy. There is evidence of improved survival in patients with sarcomatoid differentiation receiving NAC compared to RC alone. The major prognostic factors that affect survival outcomes in VH of UC include histologic variant subtype, patient age, presence of lymphovascular invasion, hydronephrosis, nodal metastasis and advanced T stage at diagnosis. Recent studies demonstrate that VH of UC are heterogenous tumors and responsiveness to NAC may be a function of the molecular subtypes present.ConclusionsBased on these findings, NAC to achieve pathologic downstaging prior to radical cystectomy is recommended for MIBC with VH. Biomarkers identified by molecular profiling with immunohistochemistry will need to be validated as predictors of response to NAC in future trials.

The Origin, Epidemiology, and Phylodynamics of Human Immunodeficiency Virus Type 1 CRF47_BF.

CRF47_BF is a circulating recombinant form (CRF) of the human immunodeficiency virus type 1 (HIV-1), the etiological agent of AIDS. CRF47_BF represents one of 19 CRFx_BFs and has a geographic focus in Spain, where it was first identified in 2010. Since its discovery, CRF47_BF has expanded considerably in Spain, predominantly through heterosexual contact (∼56% of the infections). Little is known, however, about the origin and diversity of this CRF or its epidemiological correlates, as very few samples have been available so far. This study conducts a phylogenetic analysis with representatives of all CRFx_BF sequence types along with HIV-1 M Group subtypes to validate that the CRF47_BF sequences share a unique evolutionary history. The CRFx_BF sequences cluster into a single, not well supported, clade that includes their dominant parent subtypes (B and F). This clade also includes subtype D and excludes sub-subtype F2. However, the CRF47_BF sequences all share a most recent common ancestor. Further analysis of this clade couples CRF47_BF protease-reverse transcriptase sequences and epidemiological data from an additional 87 samples collected throughout Spain, as well as additional CRF47_BF database sequences from Brazil and Spain to investigate the origin and phylodynamics of CRF47_BF. The Spanish region with the highest proportion of CRF47_BF samples in the data set was the Basque Country (43.7%) with Navarre next highest at 19.5%. We include in our analysis epidemiological data on host sex, mode of transmission, time of collection, and geographic region. The phylodynamic analysis indicates that CRF47_BF originated in Brazil around 1999–2000 and spread to Spain from Brazil in 2002–2003. The virus spread rapidly throughout Spain with an increase in population size from 2011 to 2015 and leveling off more recently. Three strongly supported clusters associated with Spanish regions (Basque Country, Navarre, and Aragon), together comprising 60.8% of the Spanish samples, were identified, one of which was also associated with transmission among men who have sex with men. The expansion in Spain of CRF47_BF, together with that of other CRFs and subtype variants of South American origin, previously reported, reflects the increasing relationship between the South American and European HIV-1 epidemics.

Variant Hepatocellular Carcinoma Subtypes According to the 2019 WHO Classification: An Imaging-Focused Review.

The 2019 5th edition of the WHO classification of digestive system tumors estimates that up to 35% of hepatocellular carcinomas (HCCs) can be classified as one of eight subtypes defined by molecular characteristics: steatohepatitic, clear cell, macrotrabecular-massive, scirrhous, chromophobe, fibrolamellar, neutrophil-rich, and lymphocyte-rich HCCs. Due to their distinct cellular and architectural characteristics, these subtypes may not display arterial phase hyperenhancement and washout appearance, which are the classic MRI features of HCC, creating challenges in noninvasively diagnosing such lesions as HCC. Moreover, certain subtypes with atypical imaging features have a worse prognosis than other HCCs. A range of distinguishing imaging features may help raise suspicion that a liver lesion represents one of these HCC subtypes. In this review, we describe the MRI features that have been reported in association with various HCC subtypes according to the 2019 WHO classification, with attention given to the current understanding of these subtypes' pathologic and molecular bases and relevance to clinical practice. Imaging findings that differentiate the subtypes from benign liver lesions and non-HCC malignancies are highlighted. Familiarity with these sub-types and their imaging features may allow the radiologist to suggest their presence, though histologic analysis remains needed to establish the diagnosis.

PD53-05 BLADDER CANCER TUMOROIDS AND NORMAL UROTHELIAL ORGANOIDS AS NEAR-PATIENT MODELS TO STUDY BLADDER CANCER TUMORIGENESIS AND PREDICT TREATMENT RESPONSE

You have accessJournal of UrologyCME1 May 2022PD53-05 BLADDER CANCER TUMOROIDS AND NORMAL UROTHELIAL ORGANOIDS AS NEAR-PATIENT MODELS TO STUDY BLADDER CANCER TUMORIGENESIS AND PREDICT TREATMENT RESPONSE Maryam Akbarzadeh, Mathijs Scholtes, Ameneh Bazrafshan, Tokameh Mahmoudi, and Tahlita Zuiverloon Maryam AkbarzadehMaryam Akbarzadeh More articles by this author , Mathijs ScholtesMathijs Scholtes More articles by this author , Ameneh BazrafshanAmeneh Bazrafshan More articles by this author , Tokameh MahmoudiTokameh Mahmoudi More articles by this author , and Tahlita ZuiverloonTahlita Zuiverloon More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002630.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Clinical outcome linked to bladder cancer (BC) stage, grade and histology can be attributed to distinct molecular profiles and a better understanding of these molecular profiles could lead to novel rational treatment strategies. We previously successfully set-up a BC tumoroid and urothelial organoid culture protocol to investigate the biological role of molecular alterations in BC. Here, the aim was to characterize previously established patient-derived tumoroids and normal organoids generated from BC patients with various clinical and molecular background. Additionally, we aimed to investigate whether patient-derived tumoroids can serve as a predictive model to guide patient treatment. METHODS: Tumoroid/organoid cultures and originating tissue were characterized by H&E staining, SNaPshot analysis for hTERT, FGFR3 and PIK3CA hotspot mutations, and copy number aberrations (CNA) analysis using SNP-microarrays. Expression of urothelial differentiation markers was investigated by immunofluorescence (CK5, CK20, GATA3) and qPCR (CD44, CK14, GATA3, FOXA1, UPK3A) in tumoroids/organoids treated with different culture conditions. Originating tissues were characterized by immunohistochemistry (CK5, CK14, GATA3, CK20). Tumoroid ex vivo drug response to cisplatin and FGFR-inhibitor erdafitinib treatment was investigated by AlamarBlue and CellTiter-Glo cell viability assays. RESULTS: Tumor-tumoroid pairs showed corresponding hotspot mutations, CNAs, and similar expression of basal/luminal differentiation markers. In case of divergent differentiation or variant histological subtypes, the tumoroid phenotypically resembled the tissue of origin. Tumoroids generated from cisplatin-resistant patients demonstrated resistance to serum concentrations of cisplatin, while FGFR3-mutant tumoroids responded to erdafitinib treatment. As for organoids, no genetic aberrations were detected in originating normal urothelium and organoids did not acquire CNAs or hotspot mutations over freeze-thaw cycles or several months of ex vivo culturing. The organoids could be differentiated to recapitulate the normal urothelial microanatomy showing lumen formation and spatial organization of luminal/basal cells. CONCLUSIONS: We successfully characterized genetically stable BC tumoroid and urothelial organoid lines that molecularly resemble originating tissues. Additionally, we demonstrated that tumoroids can be used to investigate ex vivo treatment response. Source of Funding: Erasmus MC mRACE Grant and TKI-LSH Match Grant © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e911 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maryam Akbarzadeh More articles by this author Mathijs Scholtes More articles by this author Ameneh Bazrafshan More articles by this author Tokameh Mahmoudi More articles by this author Tahlita Zuiverloon More articles by this author Expand All Advertisement PDF DownloadLoading ...

Somatostatin Receptor Splicing Variant sst5TMD4 Overexpression in Glioblastoma Is Associated with Poor Survival, Increased Aggressiveness Features, and Somatostatin Analogs Resistance.

Glioblastoma (GBM) is the most malignant and lethal brain tumor. Current standard treatment consists of surgery followed by radiotherapy/chemotherapy; however, this is only a palliative approach with a mean post-operative survival of scarcely ~12–15 months. Thus, the identification of novel therapeutic targets to treat this devastating pathology is urgently needed. In this context, the truncated splicing variant of the somatostatin receptor subtype 5 (sst5TMD4), which is produced by aberrant alternative splicing, has been demonstrated to be overexpressed and associated with increased aggressiveness features in several tumors. However, the presence, functional role, and associated molecular mechanisms of sst5TMD4 in GBM have not been yet explored. Therefore, we performed a comprehensive analysis to characterize the expression and pathophysiological role of sst5TMD4 in human GBM. sst5TMD4 was significantly overexpressed (at mRNA and protein levels) in human GBM tissue compared to non-tumor (control) brain tissue. Remarkably, sst5TMD4 expression was significantly associated with poor overall survival and recurrent tumors in GBM patients. Moreover, in vitro sst5TMD4 overexpression (by specific plasmid) increased, whereas sst5TMD4 silencing (by specific siRNA) decreased, key malignant features (i.e., proliferation and migration capacity) of GBM cells (U-87 MG/U-118 MG models). Furthermore, sst5TMD4 overexpression in GBM cells altered the activity of multiple key signaling pathways associated with tumor aggressiveness/progression (AKT/JAK-STAT/NF-κB/TGF-β), and its silencing sensitized GBM cells to the antitumor effect of pasireotide (a somatostatin analog). Altogether, these results demonstrate that sst5TMD4 is overexpressed and associated with enhanced malignancy features in human GBMs and reveal its potential utility as a novel diagnostic/prognostic biomarker and putative therapeutic target in GBMs.

What's in a Name? A Cost-Effectiveness Analysis of the Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features' Nomenclature Revision.

Background: The noninvasive subtype of encapsulated follicular variant of papillary thyroid carcinoma (eFVPTC) has been reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) in 2016 to reflect the indolent behavior and favorable prognosis of this type of tumor. This terminology change has also de-escalated its management approach from cancer treatment to a more conservative treatment strategy befitting a benign thyroid neoplasm. Objective: To characterize the reduced health care costs and improved quality of life (QOL) from management of NIFTP as a nonmalignant tumor compared with the previous management as eFVPTC. Methods: A cost-effectiveness analysis was performed by creating Markov models to simulate two management strategies for NIFTP: (i) de-escalated management of the tumor as NIFTP involving lobectomy with reduced follow-up, (ii) management of the tumor as eFVPTC involving completion thyroidectomy/radioactive iodine ablation for some patients, and follow-up recommended for carcinoma. The model was simulated for 5 and 20 years following diagnosis of NIFTP. Aggregate costs and quality-life years were measured. One-way sensitivity analysis was performed for all variables. Results: Over a five-year simulation period, de-escalated management of NIFTP had a total cost of $12,380.99 per patient while the more aggressive management of the tumor as eFVPTC had a total cost of $16,264.03 per patient (saving $3883.05 over five years). Management of NIFTP provided 5.00 quality-adjusted life years, whereas management as eFVPTC provided 4.97 quality-adjusted life years. Sensitivity analyses showed that management of NIFTP always resulted in lower costs and greater quality-adjusted life years (QALYs) over the sensitivity ranges for individual variables. De-escalated management for NIFTP is expected to produce ∼$6-42 million in cost savings over a five-year period for these patients, and incremental 54-370 QALYs of increased utility in the United States. Conclusion: The degree of cost savings and improved patient utility of de-escalated NIFTP management compared with traditional management was estimated to be $3883.05 and 0.03 QALYs per patient. We demonstrate that these findings persisted in sensitivity analysis to account for variability in recurrence rate, surveillance approaches, and other model inputs. These findings allow for greater understanding of the economic and QOL impact of the NIFTP reclassification.

Surveillance, Epidemiology, and End Results Database update for pediatric thyroid carcinomas incidence and survival trends 2000–2016

ObjectiveReview the trends in pediatric thyroid carcinomas using the Surveillance, Epidemiology, and End Results (SEER) Database. MethodsInstitutional review board approval was obtained from Mercy-Bon Secours. The National Cancer Institute's SEER database was used for all cases of pediatric thyroid cancer between the years 2000 and 2016 for patients aged 0–19. Patients were grouped by carcinoma histological subtype, disease specific survival based on treatment modality, and demographic data. Treatment methods were compared using Fifteen-Year Disease Specific Survival Curves. Results1175 pediatric patients were identified. The average age-adjusted rate of malignancy was 0.3 per 100,000 patients. Incidence of pediatric thyroid cancer was approximately 1:3.6, male to female. The papillary follicular variant histological subtype was the most common (n = 689, 58.6%), followed by papillary (n = 223, 18.9%), follicular (n = 153, 13.1%), and medullary (n = 110, 9.4%). Overall incidence of thyroid carcinomas increased with age, highest in patients aged 15–19 (69.8%). Incidence of medullary thyroid carcinomas was highest in patients aged 0–9. Patients aged 10–19 treated with surgery alone had the highest disease specific survival fifteen-years past initial diagnoses and treatment in all histologic subtypes (p < 0.05). Patients with metastatic medullary thyroid carcinoma at initial diagnosis who underwent surgery alone showed significantly poorer fifteen-year disease specific survival when compared to other histologic subtypes (p < 0.05). ConclusionThere was improved prognosis in pediatric thyroid carcinomas if diagnosed and treated early. All four major histological subtypes exhibit an increase in overall survival rates, (excluding medullary carcinomas).

Aortic Arch Variants and Anomalies: Embryology, Imaging Findings, and Clinical Considerations.

There is a wide spectrum of congenital anomalies or variations of the aortic arch, ranging from non-symptomatic variations that are mostly detected incidentally to clinically symptomatic variations that cause severe respiratory distress or esophageal compression. Some of these may be accompanied by other congenital heart diseases or chromosomal anomalies. The widespread use of multidetector computed tomography (CT) in clinical practice has resulted in incidental detection of several variations of the aortic arch in adults. Thus, radiologists and clinicians should be aware of the classification of aortic arch anomalies and carefully look for imaging features associated with a high risk of clinical symptoms. Understanding the embryological development of the aortic arch aids in the classification of various subtypes of aortic arch anomalies and variants. For accurate diagnosis and precise evaluation of aortic arch anomalies, cross-sectional imaging modalities, such as multidetector CT or magnetic resonance imaging, play an important role by providing three-dimensional reconstructed images. In this review, we describe the embryological development of the thoracic aorta and discuss variations and anomalies of the aortic arch along with their clinical implications.

The different recanalization rates of posterior communicating artery aneurysms with a fetal posterior communicating artery and anterior communicating artery aneurysms with a variation of the unilateral A1 segment.

Posterior communicating artery (PcomA) aneurysms are more likely to recanalize than anterior communicating artery (AcomA) aneurysms. However, it is still unclear whether the recanalization rate of these aneurysms is a result of involvement from the fetal posterior cerebral artery (fPCA) in PcomA aneurysms and variation of the unilateral A1 segment in AcomA aneurysms. The purpose of this study is to retrospectively evaluate the different recanalization rates between PcomA aneurysms with fPCA and AcomA aneurysms with a variation of the unilateral A1 segment. We retrospectively collected information regarding 214 patients, each with communicating segment aneurysms between January 2013 and January 2020. Follow-up documentation on clinical and imaging data was comparatively analyzed between variant types, and recanalization rates of the variant and normal types were analyzed by stratification. Of the 84 variant-type aneurysms (PcomA with fPCA and AcomA with a variation of the unilateral A1 segment, 41/43), complete recanalization occurred in 23 patients (27.4%), and it was significantly more likely to occur in PcomA aneurysms with fPCA (39.1%) than in AcomA aneurysms with a variation of the unilateral A1 segment (16.3%). Stent-assisted coil embolization (SACE) has been shown to reduce recanalization (OR =0.092, 95% CI: 0.011 to 0.790, P=0.03). Additionally, variant types and the normal type (non-fetal, 106, and bilateral A1 symmetry, 24) have different odds ratios (OR) of recanalization (P=0.04), and the OR of the variant subtypes was significant, unlike the normal type (P=0.49). This study suggests that PcomA aneurysms with fPCA are more likely to recanalize than AcomA aneurysms with a variation of the unilateral A1 segment.

A Case of Lung Adenocarcinoma Response to Alectinib Harboring a Rare EML4-ALK Variant, Exon 6 of EML4 Fused to Exon 18 of ALK

More than 20 types of ALK fusion variant subtypes have been identified, including different fusion partner genes or EML4-ALK fusions with different breakpoints. However, different ALK fusions show different sensitivities to ALK-tyrosine kinase inhibitors (ALK-TKIs) and the emergence of rare fusions brings great challenges to the target therapy in clinic. We report a rare EML4-ALK (E6;A18) fusion in a patient with lung adenocarcinoma that responded well to alectinib. This is the second case of this rare variant reported but the first report of response to an ALK-TKI. This evidence is the first to show that alectinib may be effective for this rare fusion type of non-small cell lung cancer, and these findings have important implications for drug selection in patients with this subtype. Further studies are needed to understand the function of this variant.

Comprehensive in Vitro Characterization of CXCR4WHIM variants to Decipher Genotype-Phenotype Correlations in WHIM Syndrome

▪Background: WHIM (Wart, Hypogammaglobulinemia, Infections, Myelokathexis) syndrome is a rare, autosomal-dominant primary immunodeficiency with neutropenia and lymphopenia. The clinical presentation may include recurrent infections, and increased susceptibility to human papillomavirus. In >80% of cases, WHIM syndrome is caused by heterozygous gain-of-function (GOF) mutations in C-X-C chemokine receptor 4 (CXCR4), with >12 variants reported in WHIM syndrome to date (nonsense [NS], frameshift [FS], and missense[MS]) spanning 27 C-terminal amino acids . These mutations cause hyperactivation of downstream signaling and retention of WBC in the bone marrow (McDermott D, et al. Immunol Rev. 2019;287(1):91-102; Beaussant S, et al. Orphanet J Rare Dis. 2012;7(71):1-14). To date, a comprehensive study characterizing the functional abnormalities caused by pathogenic CXCR4 mutations and correlating these measures with clinical presentation in patients has not been conducted. Here, we aimed to establish genotype-phenotype correlations for all known pathogenic variants using in vitro functional assays. These assays characterize CXCR4 receptor trafficking and downstream signaling, which will enable the long-term goal of assessing pathogenicity of novel CXCR4 variants of uncertain significance (VUS). We further aimed to assess the in vitro response of each variant to mavorixafor, an investigational CXCR4 antagonist.Methods: We used the CXCR4-negative K562 cell line as a model system to express all 14 known CXCR4 variants identified in patients diagnosed with WHIM syndrome (previous reports, ClinVar, and genetic screening initiatives [Invitae PATH4WARD]). The effects of the mutations on CXCR4 receptor trafficking (internalization and degradation), downstream signaling (Ca 2+ mobilization, cAMP inhibition, ERK and AKT activation), and chemotaxis were studied in parallel in a series of assays in cells stimulated with the natural ligand CXCL12. All in vitro functional parameters characterized were investigated for potential correlations with the clinical phenotypes reported for each variant, including disease manifestations and biomarkers.Results: The most conserved feature of the 14 CXCR4 variants was an impaired receptor internalization in response to CXCL12, evidenced by higher percentage of CXCR4 receptors remaining on the cell surface compared to untreated control, with truncated variants showing maximum impairment and the MS variant E343K being least affected. The decreased CXCR4 internalization correlated with both decreased CXCR4 degradation and increased cAMP inhibition. When stimulated with CXCL12, most variants demonstrated a higher amplitude and duration of ERK and AKT activation. Chemotactic responses to CXCL12 were diverse, depending on the variant sequence and subtype. While Ca 2+ mobilization was not enhanced compared to wild-type (WT) CXCR4-expressing cells in this assay, mavorixafor demonstrated inhibition of Ca 2+ mobilization in all CXCR4 mutant cells with a trend toward greater effect in the NS variants. In addition, both ERK and AKT activation decreased with increasing concentration of mavorixafor. Correlation analyses of the functional parameters in cells expressing mutated or WT CXCR4 and clinical manifestations or WBC counts in patients with these mutations revealed that the CXCR4 internalization defect strongly correlated with severity of peripheral blood cytopenias (ie, decreases in absolute neutrophil counts, and in CD3+ and CD4+ T-cell levels), which was paralleled by an increased susceptibility to recurrent infections. In addition, AKT hyperactivation correlated with lower IgA and decreased CD4+ T-cell levels (Figure).Conclusions: In the current study, we performed a detailed functional analysis of the entire spectrum of CXCR4 WHIM mutations known to date. In vitro CXCR4 receptor internalization correlates with WBC cytopenias and an increased susceptibility to recurrent infections in patients with CXCR4 GOF mutations. These data suggest that CXCR4 internalization and AKT activation may be used as key assays for the assessment of CXCR4 variant pathogenicity in vitro and potentially as WHIM-related disease biomarkers. Additionally, all tested CXCR4 variant cell lines were sensitive to mavorixafor at clinically relevant concentrations, rescuing defective GOF signaling toward that of WT CXCR4-expressing cells. [Display omitted] DisclosuresZmajkovicova: X4 Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Maier-Munsa: X4 Pharmaceuticals: Current Employment. Maierhofer: X4 Pharmaceuticals: Current Employment. Taveras: X4 Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Badarau: X4 Pharmaceuticals: Current equity holder in publicly-traded company, Ended employment in the past 24 months.

Association of KRAS Variant Subtypes With Survival and Recurrence in Patients With Surgically Treated Intrahepatic Cholangiocarcinoma

KRAS variants are associated with tumor progression; however, the prevalence of KRAS variant subtypes and their association with survival and recurrence in patients with intrahepatic cholangiocarcinoma (ICC) after curative resection are largely unknown. To explore the prognostic association of KRAS variant subtypes with survival and recurrence in patients with ICC. In this cohort study, patients who underwent curative resection for ICC from January 2009 through December 2016 at a single hospital in China were recruited, and whole-exome sequencing, targeted sequencing, and Sanger sequencing were performed to identify KRAS variants. Kaplan-Meier and log-rank tests were used to compare overall survival (OS) and disease-free survival (DFS). Univariate and multivariate analyses were performed using the Cox proportional hazards regression model. Data were analyzed from April 2020 to January 2021. Hepatectomy in patients with ICC. The association of KRAS variant subtypes with OS and DFS. Of 1024 included patients with ICC, 621 (60.6%) were male, and the mean (SD) age was 59.2 (10.2) years. A total of 14 different subtypes of KRAS somatic variants affecting 127 patients (12.4%) were identified. G12D was the most frequent allele in this cohort, accounting for 55 of 127 identified KRAS variants (43.3%), followed by G12V (25 [19.7%]), G12C (9 [7.1%]), and G13D (8 [6.3%]). Compared with patients with wild-type KRAS, patients with variant KRAS were more likely to have high levels of carbohydrate antigen 19-9 (92 of 127 [72.4%] vs 546 of 897 [60.9%]; P = .01) and γ-glutamyltransferase (72 of 127 [56.7%] vs 420 of 897 [46.8%]; P = .04). Multivariable analysis revealed that G12 KRAS variants but not non-G12 KRAS variants were independently associated with worse OS (hazard ratio [HR], 1.69; 95% CI, 1.31-2.18; P < .001) and DFS (HR, 1.47; 95% CI, 1.16-1.88; P = .002). Among the patients with G12 KRAS variants, the G12V KRAS variant was the strongest prognostic determinant for the worst OS (HR, 3.05; 95% CI, 1.94-4.79; P < .001) and DFS (HR, 1.79; 95% CI, 1.13-2.85; P = .01). In this cohort study, the distribution of KRAS variant subtypes was characterized in a large cohort of patients with ICC from China. The presence of G12 KRAS variants but not non-G12 KRAS variants was associated with worse survival and increased risk of recurrence. Patients with the G12V variant exhibited the worst outcomes in the whole cohort.

Lineage-restricted neoplasia driven by Myc defaults to small cell lung cancer when combined with loss of p53 and Rb in the airway epithelium.

Small cell lung cancer (SCLC) is an aggressive neuroendocrine cancer characterized by loss of function TP53 and RB1 mutations in addition to mutations in other oncogenes including MYC. Overexpression of MYC together with Trp53 and Rb1 loss in pulmonary neuroendocrine cells of the mouse lung drives an aggressive neuroendocrine low variant subtype of SCLC. However, the transforming potential of MYC amplification alone on airway epithelium is unclear. Therefore, we selectively and conditionally overexpressed MYC stochastically throughout the airway or specifically in neuroendocrine, club, or alveolar type II cells in the adult mouse lung. We observed that MYC overexpression induced carcinoma in situ which did not progress to invasive disease. The formation of adenoma or SCLC carcinoma in situ was dependent on the cell of origin. In contrast, MYC overexpression combined with conditional deletion of both Trp53 and Rb1 exclusively gave rise to SCLC, irrespective of the cell lineage of origin. However, cell of origin influenced disease latency, metastatic potential, and the transcriptional profile of the SCLC phenotype. Together this reveals that MYC overexpression alone provides a proliferative advantage but when combined with deletion of Trp53 and Rb1 it facilitates the formation of aggressive SCLC from multiple cell lineages.

NAA80 bi-allelic missense variants result in high-frequency hearing loss, muscle weakness and developmental delay.

The recent identification of NAA80/NAT6 as the enzyme that acetylates actins generated new insight into the process of post-translational actin modifications; however, the role of NAA80 in human physiology and pathology has not been clarified yet. We report two individuals from a single family harbouring a homozygous c.389T>C, p.(Leu130Pro) NAA80 genetic variant. Both individuals show progressive high-frequency sensorineural hearing loss, craniofacial dysmorphisms, developmental delay and mild proximal and axial muscle weakness. Based on the molecular structure, we predicted and confirmed the NAA80 c.389T>C, p.(Leu130Pro) variant to result in protein destabilization, causing severely decreased NAA80 protein availability. Concurrently, individuals exhibited a ∼50% decrease of actin acetylation. NAA80 individual derived fibroblasts and peripheral blood mononuclear cells showed increased migration, increased filopodia counts and increased levels of polymerized actin, in agreement with previous observations in NAA80 knock-out cells. Furthermore, the significant clinical overlap between NAA80 individuals and individuals with pathogenic variants in several actin subtypes reflects the general importance of controlled actin dynamics for the inner ear, brain and muscle. Taken together, we describe a new syndrome, caused by NAA80 genetic variants leading to decreased actin acetylation and disrupted associated molecular functions. Our work suggests a crucial role for NAA80-mediated actin dynamics in neuronal health, muscle health and hearing.

P66.01 Characterize the Heterogeneity of the Immunophenotype in Different Neuroendocrine (NE) Subtypes of Small-Cell Lung Cancer (SCLC)

SCLC is a typical neuroendocrine carcinoma, however, a variant subtype of SCLC with low expression of NE markers and a variant morphology has been reported mainly based on cell lines and xenograft models. The difference of the tumor immune microenviroment (TIME) and other clinicopathological characteristics between the two subtypes in human specimens remain to be investigated. Forty-eight resected Formalin-Fixed and Paraffin-Embedded (FFPE) SCLC tissues were collected for mRNA detection using Nanostring technology. Patients were assigned into NE-high and NE-low group according to NE gene signature score, and the expression level of immune-related genes and abundance of immunocytes estimated by CIBERSORT was compared between the two groups. Nanostring digital spatial profiling (DSP) was performed in 6 NE score paired tumors to dissect the heterogeneity of spatial distribution of immune cells and immunotherapeutic drug targets between the two subtypes. Kaplan-meier method and COX regression model was used to compare the survival of the two subtypes and identify the independent prognostic factors and potential immunotherapeutic targets respectively. Forty-eight patients were assigned into the NE-high and NE-low group respectively based on NE score. NE-low group had earlier clinical stages (P=0.030), higher positive rates of lymph nodes (P=0.017) and higher frequency of variant morphology (P=0.047) than that of NE-high group. Compared with NE-high tumors, most of the detected immune-related genes were up-regulated in NE-low tumors. CIBERSORT results indicated NE-high subtypes had a higher relative proportion of Treg cells and M2 macrophages. However, higher absolute abundance of activated mast cells, CD8+ T cells and M1 macrophages enriched in NE-low TME. DSP results showed NE-high tumors were lack of dendritic cells and macrophages in peritumor area and normal tissue compartments and also lack of effector T cells in tumor center and surrounding area. However, a set of targetable negative immune checkpoints were up-regulated in NE-low TME. The prognosis was better for NE-low patients with 5-year DFS% 75% vs.38.6% (hazard ratio [HR] 0.35, 95% confidence interval [CI] 0.08-1.46; P=0.130) and 5-year OS% 87.5% vs.53.9% (HR 0.19, 95% CI 0.03-1.43; P=0.073). SCLC patients exhibited heterogeneous NE gene expression profile, implicating two entities with distinct TIME and prognosis. Compared with NE-high subtypes, patients with NE-low tumors had higher expression of immune-related genes, showing T cell-inflamed immunophenotypes, which might be one of causes for longer survival and suggested a higher propensity to benefit from immunotherapy.

Distinct conformers of amyloid beta accumulate in the neocortex of patients with rapidly progressive Alzheimer's disease

Amyloid beta (Aβ) deposition in the neocortex is a major hallmark of Alzheimer's disease (AD), but the extent of deposition does not readily explain phenotypic diversity and rate of disease progression. The prion strain–like model of disease heterogeneity suggests the existence of different conformers of Aβ. We explored this paradigm using conformation-dependent immunoassay (CDI) for Aβ and conformation-sensitive luminescent conjugated oligothiophenes (LCOs) in AD cases with variable progression rates. Mapping the Aβ conformations in the frontal, occipital, and temporal regions in 20 AD patients with CDI revealed extensive interindividual and anatomical diversity in the structural organization of Aβ with the most significant differences in the temporal cortex of rapidly progressive AD. The fluorescence emission spectra collected in situ from Aβ plaques in the same regions demonstrated considerable diversity of spectral characteristics of two LCOs—quatroformylthiophene acetic acid and heptaformylthiophene acetic acid. Heptaformylthiophene acetic acid detected a wider range of Aβ deposits, and both LCOs revealed distinct spectral attributes of diffuse and cored plaques in the temporal cortex of rapidly and slowly progressive AD and less frequent and discernible differences in the frontal and occipital cortex. These and CDI findings indicate a major conformational diversity of Aβ accumulating in the neocortex, with the most notable differences in temporal cortex of cases with shorter disease duration, and implicate distinct Aβ conformers (strains) in the rapid progression of AD.

Clinical and molecular characteristics of epidermal growth factor receptor exon 20 insertion mutations in non-small-cell lung cancer

To evaluate the genomic and immune characteristics of non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations from a retrospective dataset with molecular spectrum, tumor mutational burden (TMB), and programmed death-ligand 1 (PD-L1) expression, as well as to evaluate the efficacy of immune checkpoint inhibitors (ICIs). A total of 283 patients with EGFR ex20ins mutations who were diagnosed with NSCLC at our hospital from August 2013 to September 2020 were enrolled in this single-center retrospective study. Among the 283 patients with EGFR ex20ins mutations, 182 patients received next-generation sequencing (NGS) test, and 51 different subtypes of insertion variants were recorded. The most common mutations were A767_V769dup (21.4%), S768_D770dup (19.2%) and A763_Y764insFQEA (7.1%). The most common co-occurring mutations were EGFR amplification (37.9%), TP53 mutation (35.0%) and PIK3CA mutation (8.7%). PD-L1 status was available for 141 patients, and 75.9% (107/141) of these samples showed negative PD-L1 expression. In the 36 cases with TMB tested by NGS, the median TMB was 4.6 mutations/Mb. Then 12 patients received ICIs monotherapy or combination therapy. No severe adverse events were observed. Low PD-L1 expression and TMB were observed in NSCLC patients harboring EGFR ex20ins mutations. Further investigations are needed to confirm the therapeutic sensitivity of ICIs in this subgroup of EGFR mutations.

Low urinary iodine is a protective factor of central lymph node metastasis in papillary thyroid cancer: a cross-sectional study

BackgroundAn abrupt increase of thyroid cancer has been witnessed paralleling the supplemented iodine intake in formerly iodine-deficient countries. And increased iodine intake has been linked to the rising incidence rate of papillary thyroid cancer (PTC). However, the correlation between iodine and clinicopathological features of PTC has not been well-characterized. This study aimed to investigate the associations between iodine intake and the clinicopathological features of PTC patients.MethodsThree hundred and fifty-nine PTC patients who received surgical treatment in Peking Union Medical College Hospital from May 2015 to November 2020 were retrospectively reviewed. The associations between urinary iodine (UI), urinary iodine/creatinine ratio (UI/U-Cr), and the clinicopathological features of PTC were analyzed. Univariate and multivariate analysis were performed to investigate the relationship between UI level and central lymph node metastasis (CLNM).ResultsThere were no significant differences in UI in different groups according to the variables studied, except that patients with CLNM had higher UI level than CLNM(−) patients. No associations were found between UI/U-Cr and clinicopathological features except variant subtypes (classic/follicular). After dividing patients into high-iodine group and low-iodine group, more patients were found to have CLNM in the high-iodine group (p = 0.02). In addition, younger age, larger tumor size, and classic variant were positively correlated with CLNM (p < 0.05). Univariate analysis showed that insufficient iodine intake (≤ 99 μg/L) was associated with decreased CLNM risk in PTC. And after defining insufficient iodine intake as ≤ 109 μg/L and above requirements as ≥ 190 μg/L, multivariate analysis showed that lower iodine was associated with CLNM in total population of PTC (OR 0.53, 95% CI 0.31–0.91) and in PTC < 1 cm (papillary thyroid microcarcinoma, PTMC) (OR 0.43, 95% CI 0.21–0.87).ConclusionsLow iodine was a protective factor for CLNM in papillary thyroid cancer, particularly in those < 1 cm. These results indicated that iodine may not only be an initiator of tumorigenesis, but also a promoter of the development of PTC.

Abstract LB043: Efficacy of Lorlatinib in Treatment-Naïve Patients (pts) With ALK-Positive Advanced Non-Small Cell Lung Cancer (NSCLC) in Relation to EML4-ALK Variant Type and ALK Mutations

Abstract BACKGROUND: Lorlatinib, a 3rd generation ALK tyrosine kinase inhibitor, has shown overall and intracranial activity in ALK+ advanced NSCLC. In the randomized, multicenter, phase 3 study in pts with previously untreated ALK+ advanced NSCLC (CROWN; NCT03052608), lorlatinib resulted in a statistically significant and clinically meaningful improvement in progression-free survival (PFS) vs crizotinib.1 To identify molecular correlates of response, we performed molecular profiling of circulating free DNA (cfDNA) and tumor tissue. METHODS: Plasma and tumor tissue samples were available from 130 and 118 pts in the lorlatinib arm, and from 125 and 104 pts in the crizotinib arm, respectively. Plasma DNA was analyzed for ALK fusions and mutations by next-generation sequencing (NGS; Guardant360, Guardant Health, Inc., Redwood City, CA, USA); tumor tissue DNA was analyzed with an ALK-mutation focused NGS panel (MolecularMD, Portland, OR, USA). Objective response rate (ORR), duration of response (DOR), and PFS were evaluated by blinded independent central review according to EML4-ALK variant type and ALK resistance mutation status. RESULTS: At screening, 19 ALK missense mutations and 1 deletion were detected in plasma of 11 pts (5 and 6 in the lorlatinib and crizotinib arms, respectively). Most pts harbored 1 mutation, but 3 pts harbored ≥3 mutations. ALK fusions were detected in plasma of 48% of pts. EML4-ALK variants 1, 2, and 3 were detected in 14.6%, 5.4%, and 13.8% and in 20.0%, 1.6%, and 16.8% of pts, in the lorlatinib and crizotinib arms, respectively. Variants 4, 5, 7, and 8 were detected in 11.5% and 7.2% of pts, and less frequent fusion partners in 1.5% and 3.2% of pts, respectively. ORRs were generally higher in the lorlatinib arm vs the crizotinib arm, regardless of variant subtypes and/or mutational status, with no striking differences between EML4-ALK variants 1, 2, and 3 (range, 72% to 86% for lorlatinib and 50% to 76% for crizotinib). Median DOR and PFS were not reached for variants 1 and 3 in the lorlatinib arm, and ranged from 5.7 to 6.5 months, and from 7.4 to 7.6 months in the crizotinib arm, respectively. CONCLUSION: Pts with untreated ALK+ advanced NSCLC had higher ORRs and potentially longer DOR and PFS across predefined biomarker subgroups when treated with lorlatinib compared with crizotinib in a phase 3 CROWN study. Based on pretreatment cfDNA analysis, lorlatinib led to similar clinical benefit regardless of the type of EML4-ALK variant or presence of ALK kinase mutations. REFERENCE: 1. Shaw AT, et al. N Engl J Med. 2020;383:2018-2029. Citation Format: Alessandra Bearz, Jean-François Martini, Jacek Jassem, Sang-We Kim, Gee-Chen Chang, Alice Shaw, Deborah Shepard, Elisa Dall'O', Anna Polli, Holger Thurm, Gerard Zalcman, Maria Rosario Garcia Campelo, Konstantin Penkov, Hidetoshi Hayashi, Benjamin J. Solomon. Efficacy of Lorlatinib in Treatment-Naïve Patients (pts) With ALK-Positive Advanced Non-Small Cell Lung Cancer (NSCLC) in Relation to EML4-ALK Variant Type and ALK Mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB043.

Cohort of Phenotype, Genotype, and Outcome of SCN Developmental and Epileptic Encephalopathies from Southern Part of India.

The SCN encephalopathies are one of the rare early childhood intractable epileptic encephalopathies associated with pleomorphic seizures, cognitive decline, motor, and behavioral abnormalities that begin in early infancy. There is a dearth of data on phenotype and genotype of SCN encephalopathies from the Indian subcontinent, hence we are reporting clinical and molecular profile and outcome of SCN developmental and epileptic encephalopathies. This is a retrospective chart review of SCN developmental and epileptic encephalopathies in a tertiary care center, Bangalore, India between January 2015 and March 2020. All children with clinical features of SCN developmental and epileptic encephalopathies and confirmed with pathogenic variants were included. A total of 50 cases of SCN developmental and epileptic encephalopathies were analyzed, 31 of them were male and the mean age of presentation was 7.8 months. Precipitating factors for the first episode of seizure were fever and vaccination accounting for 33 and 8 children, respectively. Forty (80%) children had prolonged seizures and 15 (30%) had epileptic spasms. All children had a normal birth history and normal development before the onset of seizures, which was followed by developmental delay and regression. Thirty (60%) children had behavioral difficulties, notable hyperactivity, and autistic features. Neuroimaging and the initial electroencephalogram (EEG) were normal in all patients. The mean age of abnormal EEG was 14 months. The various subtypes of SCN variants were SCN1A in 31 children followed by SCN2A and SCN9A in eight children each and SCN1B in three children. Frameshift and nonsense mutations were associated with more severe phenotype and poor outcome compared with missense mutations. Thirty-four patients partially responded to treatment and the rest were refractory. The results of genetic testing were used to guide treatment; sodium channel blocking antiepileptic drugs were discontinued in 15 patients and sodium channel blocking agents were started in 3 patients with partial response. Three out of four children on stiripentol had a partial response. The SCN developmental and epileptic encephalopathies can present with epileptic spasms in addition to other types of seizures. Epileptic spasms are more common in nonsense and frameshift mutations. The outcome is poor in children with epileptic spasms compared with those without epileptic spasms. Genetic testing helps to select antiepileptic drugs that lead to seizure reduction.