Diagnostic interobserver agreement for thyroid fine-needle aspirates: Effects of reviewer experience and molecular diagnostics

OBJECTIVES

Few cytologically indeterminate thyroid fine-needle aspirations (FNAs) harbor BRAF V600E. Here, we assess interobserver agreement for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III (atypia of undetermined significance [AUS]) FNAs harboring BRAF V600E and contrast their features with those harboring non-BRAF V600E alterations, with attention to cytopathology experience.

METHODS

Seven reviewers evaluated 5 AUS thyroid FNAs harboring BRAF V600E. To blind reviewers, cases were intermixed with 19 FNAs falling within other TBSRTC categories and in which genetic alterations other than BRAF V600E had been identified (24 FNAs total). Interobserver agreement against both "index" and most popular ("mode") diagnoses was calculated. Four additional BRAF V600E cases were independently reviewed.

RESULTS

Reviewers included 3 trainees and 3 American Board of Pathology (board)-certified cytopathologists. Board-certified cytopathologists, whose experience ranged from 2 to more than 15 subspecialty practice years, had known AUS rates. BRAF V600E was identified in 5 of 260 (2%) AUS FNAs. Interobserver agreement was higher among cytopathologists with more experience. Mode diagnosis differed from index diagnosis in 6 of 11 cases harboring RAS-like alterations; mode diagnosis was AUS in 4 of 5 BRAF V600E FNAs.

CONCLUSIONS

Atypia of undetermined significance of thyroid FNAs harboring BRAF V600E is uncommon yet relatively reproducible, particularly among pathologists with experience. It is advisable to sequence BRAF across V600 in such cases.

Low Mitotic Activity in Papillary Thyroid Cancer: A Marker for Aggressive Features and Recurrence

CONTEXT

The significance of low mitotic activity in papillary thyroid cancer (PTC) is largely undefined.

OBJECTIVE

We aimed to determine the behavioral landscape of PTC with low mitotic activity compared to that of no- and high-mitotic activity.

METHODS

A single-institution consecutive series of PTC patients from 2018-2022 was reviewed. Mitotic activity was defined as no mitoses, low (1-2 mitoses/2 mm2) or high (≥3 mitoses/2 mm2) per the World Health Organization. The 2015 American Thyroid Association risk stratification was applied to the cohort, and clinicopathologic features were compared between groups. For patients with ≥6 months follow-up, Cox regression analyses for recurrence were performed.

RESULTS

640 PTCs were included - 515 (80.5%) no mitotic activity, 110 (17.2%) low mitotic activity, and 15 (2.3%) high mitotic activity. Overall, low mitotic activity exhibited rates of clinicopathologic features including vascular invasion, gross extrathyroidal extension, and lymph node metastases in between those of no- and high-mitotic activity. PTCs with low mitotic activity had higher rates of intermediate- and high-risk ATA risk stratification compared to those with no mitotic activity (p < 0.001). Low mitotic activity PTCs also had higher recurrence rates (15.5% vs. 4.5%, p < 0.001). Low mitotic activity was associated with recurrence, independent of the ATA risk stratification (HR 2.96; 95% CI 1.28-6.87, p = 0.01).

CONCLUSIONS

Low mitotic activity is relatively common in PTC and its behavior lies within a spectrum between no- and high-mitotic activity. Given its association with aggressive clinicopathologic features and recurrence, low mitotic activity should be considered when risk stratifying PTC patients for recurrence.

Depth of invasion as an independent prognostic factor in early-stage oral cavity squamous cell carcinoma

PURPOSE

To determine the significance of depth of invasion as a predictor of recurrence and mortality in tongue and non-tongue early-stage oral cavity squamous cell carcinoma patients treated with surgery and no postoperative radiotherapy.

MATERIALS AND METHODS

344 patients with oral cavity squamous cell carcinoma from 2005 to 2022 at a tertiary academic medical center were reviewed. Patients were included if they had newly diagnosed, previously untreated T1-T2N0 disease treated with surgery alone that was observed within a follow-up of 5 years. For each patient, anatomic site of oral cavity squamous cell carcinoma was categorized as either tongue or non-tongue. Cox proportional hazards regression analyses were performed to determine the association of depth of invasion with recurrence and mortality, with anatomic site, smoking status, and age at biopsy as covariates. Model assumptions were tested by statistical and graphical evaluation using Schoenfeld residuals.

RESULTS

Of 108 patients with T1-T2N0 disease, 78 (72.2 %) had tongue disease, and 30 (27.8 %) had non-tongue disease. Median follow-up was 18.2 months (range, 0.01-58.2 months). In the Cox proportional hazards models, with adjustment for anatomic site and other covariates, depth of invasion positively predicted recurrence (HR 1.16, 95 % CI: 1.01-1.32, p = 0.034) and death (HR 1.42, 95 % CI: 1.11-1.83, p = 0.006).

CONCLUSIONS

Depth of invasion is an independent predictor of recurrence and death across early-stage tongue and non-tongue squamous cell carcinoma. Therefore, depth of invasion may indicate a need for more aggressive treatment than surgery alone, such as postoperative radiotherapy, even in the absence of other adverse features on pathology within the early-stage population.

Use of the Afirma Xpression Atlas for cytologically indeterminate, Afirma Genomic Sequencing Classifier suspicious thyroid nodules: Clinicopathologic analysis with postoperative molecular testing

OBJECTIVES

Afirma has recently introduced its Xpression Atlas (XA) as an adjunct to its Genomic Sequencing Classifier (GSC) for risk stratification of cytologically indeterminate thyroid nodules. We evaluated the performance of Afirma XA and associated pathologic findings for Afirma GSC suspicious nodules.

METHODS

Intradepartmental records of thyroid fine-needle aspirations (FNAs) from January 2021 to December 2022 were identified and reviewed for patient and nodule characteristics, FNA findings, molecular test results, and final surgical pathology, if available.

RESULTS

Material for Afirma GSC testing was collected in 624 thyroid FNAs, and 148 (24%) were classified as cytologically indeterminate. Afirma GSC testing was successful in 132 (89%) of those cases, of which 35 (27%) were Afirma GSC suspicious. Afirma XA testing was positive in 11 cases (11/35 [31%]). Eight (73%) patients underwent surgery that revealed 7 patients with papillary thyroid carcinoma and 1 patient with noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) (risk of malignancy: 100% [8/8]). Among the 24 patients with negative Afirma XA results, 19 (79%) underwent surgery, revealing 5 patients with malignancy and 3 patients with NIFTP (risk of malignancy: 42% [8/19]). Overall, the risk of malignancy for Afirma GSC suspicious nodules was 59% (16/27).

CONCLUSIONS

Afirma XA improved risk stratification of thyroid disease with a high risk of malignancy in Afirma GSC suspicious nodules. A negative Afirma XA result, however, should not be used as a rule-out test.

Correlation Between Laryngoscopic Appearance and Histopathology in Vocal Fold Cysts

OBJECTIVES/HYPOTHESIS

Cysts are benign vocal fold lesions typically divided into mucous retention or epidermoid subtypes. The conventional paradigm that the former are translucent and the latter opaque fails to encompass the heterogeneity of cyst appearance on laryngoscopy. This study aims to characterize the relationships between clinical cyst characteristics and histopathology.

STUDY DESIGN

Retrospective cohort METHODS: Clinicodemographic data, videostroboscopy findings, and histopathology results were retrospectively reviewed for adults who underwent surgical excision of vocal fold cysts at our institution between 2006 and 2021.

RESULTS

Diagnostic histopathologic material was available for 69 patients (age: 50.4 ± 15.1 years, 68.1% female). Clinically, most cysts were opaque (69.6%) and located at the vibratory margin (82.6%). 11.6% were infraglottic. Significant associations existed between cyst location and epithelial type, with infraglottic cysts and those at the superior surface more commonly exhibiting ductal (P = 0.003) and squamous (P = 0.002) epithelium, respectively. Cyst opacity did not correlate with histopathology (P = 0.415). Epidermoid cysts were more likely to exhibit clinical inflammation (P = 0.002).

CONCLUSIONS

Stroke and the need for immediate assistance at the place of onset: the future of mandatory training for lay people in Italy

Introduction

Lay training is essential to manage emergencies properly, although patients or bystanders need increased recognition of medical urgencies such as strokes. In Italy, as defined by Legislative Decree 81/08, all companies must train employees responsible for correctly recognizing and managing medical emergencies. Our study aims to evaluate the characteristics of medical emergencies concerning patients with a possible stroke in the Lombardy Region.

Methods

A retrospective observational study was conducted. All missions performed by Regional Agency for Emergencies and Urgencies (Agenzia Regionale Emergenza Urgenza - AREU) in which the patient presented a possible stroke, recorded in the SAS-Areu database, were analyzed. The study period was from January 1, 2019, to December 31, 2019.

Results

10,201 patients with possible stroke were rescued, of whom only 540 (5.3%) occurred in workplaces. In workplaces, the percentage of males with a possible stroke was higher (62.2% vs 45.2%; p<0.01) and the mean age of rescued patients was lower (64.7 vs 77.5; p<0.01).

Conclusions

A stroke occurs less frequently in the workplace, while most events occur at home. Man-datory training on early stroke recognition should be extended to schools and conveyed through a media information campaign. Lay training is the first point in the chain of survival; redefining training is critical for the future.

Perineural Invasion in Papillary Thyroid Cancer: A Rare Indicator of Aggressive Disease

BACKGROUND

Perineural invasion (PNI) is associated with aggressive tumor behavior, increased locoregional recurrence, and decreased survival in many carcinomas. However, the significance of PNI in papillary thyroid cancer (PTC) is incompletely characterized.

METHODS

Patients diagnosed with PTC and PNI from 2010-2020 at a single, academic center were identified and matched using a 1:2 scheme to patients without PNI based on gross extrathyroidal extension (ETE), nodal metastasis, positive margins, and tumor size (±4 cm). Mixed and fixed effects models were used to analyze the association of PNI with extranodal extension (ENE)-a surrogate marker of poor prognosis.

RESULTS

In total, 78 patients were included (26 with PNI, 52 without PNI). Both groups had similar demographics and ultrasound characteristics preoperatively. Central compartment lymph node dissection was performed in most patients (71%, n = 55), and 31% (n = 24) underwent a lateral neck dissection. Patients with PNI had higher rates of lymphovascular invasion (50.0% vs. 25.0%, p = 0.027), microscopic ETE (80.8% vs. 44.0%, p = 0.002), and a larger burden [median 5 (interquartile range [IQR] 2-13) vs. 2 (1-5), p = 0.010] and size [median 1.2 cm (IQR 0.6-2.6) vs. 0.4 (0.2-1.4), p = 0.008] of nodal metastasis. Among patients with nodal metastasis, those with PNI had an almost fivefold increase in ENE [odds ratio [OR] 4.9 (95% confidence interval [CI] 1.5-16.5), p = 0.008] compared with those without PNI. More than a quarter (26%) of all patients had either persistent or recurrent disease over follow-up (IQR 16-54 months).

CONCLUSIONS

PNI is a rare, pathologic finding that is associated with ENE in a matched cohort. Additional investigation into PNI as a prognostic feature in PTC is warranted.

Analysis of a pre-2017 follicular variant papillary thyroid carcinoma cohort reclassified as noninvasive follicular thyroid neoplasm with papillary-like features (NIFTP): an 11-year retrospective single institution experience

INTRODUCTION

Noninvasive follicular thyroid neoplasm with papillary-like features (NIFTP), represents a distinct class of thyroid neoplasms with very low risk of adverse outcome and a set of strict histologic criteria. Introduction of NIFTP as a non-cancer has had an appreciable decrease in risk of malignancy and body of literature on this entity continues to grow. In this study, we reviewed clinical, fine-needle aspiration cytology (FNAC), imaging, and molecular findings of histologically proven NIFTPs at our institution.

MATERIALS AND METHODS

Thyroid resections during an 11-year period, with histologic diagnosis of follicular variant of papillary thyroid carcinoma (FVPTC), were retrospectively reviewed to identify NIFTP. Ultrasonographic appearance, FNA findings, and molecular findings were also reviewed.

RESULTS

Of 244 cases of FVPTC identified, 74 (30%) cases were reclassified as NIFTP. Mean tumor size was 2.5 cm. Of 33 patients with lymph node dissection, none had lymph node metastases. On imaging, 36 NIFTP (49%) showed vascularity, 25 (33%) were isoechoic to hypoechoic, there were calcifications in 14 cases (19%), and 7 cases (9%) showed a hypoechoic rim. Bethesda III/IV was the most common interpretation rendered on FNAC (31%). Seven cases had NRAS mutations and 1 case had BRAF V600E mutation. The remaining cases were either negative for BRAF V600E or had no identifiable molecular alterations.

CONCLUSIONS

A significant percentage of tumors previously diagnosed as FVPTC were reclassified as NIFTP. This tumor cannot be reliably diagnosed preoperatively on FNAC, shows no characteristic features on ultrasound and has low suspicion of malignancy. BRAF V600E mutations are infrequent in NIFTP.

Transcriptomic analysis predicts the risk of progression of premalignant lesions in human tongue

The 5-year survival rate for patients with oral squamous cell carcinomas (SCC), including tongue SCC, has not significantly improved over the last several decades. Oral potentially malignant disorders (OPMD), including oral dysplasias, are oral epithelial disorders that can develop into oral SCCs. To identify molecular characteristics that might predict conversion of OPMDs to SCCs and guide treatment plans, we performed global transcriptomic analysis of human tongue OPMD (n = 9) and tongue SCC (n = 11) samples with paired normal margin tissue from patients treated at Weill Cornell Medicine. Compared to margin tissue, SCCs showed more transcript changes than OPMDs. OPMDs and SCCs shared some altered transcripts, but these changes were generally greater in SCCs than OPMDs. Both OPMDs and SCCs showed altered signaling pathways related to cell migration, basement membrane disruption, and metastasis. We suggest that OPMDs are on the path toward malignant transformation. Based on patterns of gene expression, both OPMD and tongue SCC samples can be categorized into subclasses (mesenchymal, classical, basal, and atypical) similar to those seen in human head and neck SCC (HNSCC). These subclasses of OPMDs have the potential to be used to stratify patient prognoses and therapeutic options for tongue OPMDs. Lastly, we identified a gene set (ELF5; RPTN; IGSF10; CRMP1; HTR3A) whose transcript changes have the power to classify OPMDs and SCCs and developed a Firth logistic regression model using the changes in these transcripts relative to paired normal tissue to validate pathological diagnosis and potentially predict the likelihood of an OPMD developing into SCC, as data sets become available.

Metastatic pancreatic neuroendocrine tumors feature elevated T cell infiltration

Pancreatic neuroendocrine tumors (PNETs) are malignancies arising from the islets of Langerhans. Therapeutic options are limited for the over 50% of patients who present with metastatic disease. We aimed to identify mechanisms to remodel the PNET tumor microenvironment (TME) to ultimately enhance susceptibility to immunotherapy. The TMEs of localized and metastatic PNETs were investigated using an approach that combines RNA-Seq, cancer and T cell profiling, and pharmacologic perturbations. RNA-Seq analysis indicated that the primary tumors of metastatic PNETs showed significant activation of inflammatory and immune-related pathways. We determined that metastatic PNETs featured increased numbers of tumor-infiltrating T cells compared with localized tumors. T cells isolated from both localized and metastatic PNETs showed evidence of recruitment and antigen-dependent activation, suggestive of an immune-permissive microenvironment. A computational analysis suggested that vorinostat, a histone deacetylase inhibitor, may perturb the transcriptomic signature of metastatic PNETs. Treatment of PNET cell lines with vorinostat increased chemokine CCR5 expression by NF-κB activation. Vorinostat treatment of patient-derived metastatic PNET tissues augmented recruitment of autologous T cells, and this augmentation was substantiated in a mouse model of PNET. Pharmacologic induction of chemokine expression may represent a promising approach for enhancing the immunogenicity of metastatic PNET TMEs.

Genomic signature of Fanconi anaemia DNA repair pathway deficiency in cancer

Fanconi anaemia (FA), a model syndrome of genome instability, is caused by a deficiency in DNA interstrand crosslink repair resulting in chromosome breakage^1-3. The FA repair pathway protects against endogenous and exogenous carcinogenic aldehydes^4-7. Individuals with FA are hundreds to thousands fold more likely to develop head and neck (HNSCC), oesophageal and anogenital squamous cell carcinomas⁸ (SCCs). Molecular studies of SCCs from individuals with FA (FA SCCs) are limited, and it is unclear how FA SCCs relate to sporadic HNSCCs primarily driven by tobacco and alcohol exposure or infection with human papillomavirus⁹ (HPV). Here, by sequencing genomes and exomes of FA SCCs, we demonstrate that the primary genomic signature of FA repair deficiency is the presence of high numbers of structural variants. Structural variants are enriched for small deletions, unbalanced translocations and fold-back inversions, and are often connected, thereby forming complex rearrangements. They arise in the context of TP53 loss, but not in the context of HPV infection, and lead to somatic copy-number alterations of HNSCC driver genes. We further show that FA pathway deficiency may lead to epithelial-to-mesenchymal transition and enhanced keratinocyte-intrinsic inflammatory signalling, which would contribute to the aggressive nature of FA SCCs. We propose that the genomic instability in sporadic HPV-negative HNSCC may arise as a result of the FA repair pathway being overwhelmed by DNA interstrand crosslink damage caused by alcohol and tobacco-derived aldehydes, making FA SCC a powerful model to study tumorigenesis resulting from DNA-crosslinking damage.

Enhancing COVID 19 vaccination coverage in Sierra Leone

 

The project aim to support Sierra Leone in enhancing vaccination coverage. BACKGROUND In November 2021, the vaccination coverage rate was 7% for one dose and 4% for two. According with EPI program, the main problem was not the lack of vaccines (already provided by different donors) but the need of support (training, motivation, allowances) to health personnel. Lombardy project involved 31 local vaccination teams performing a refresh training, followed, by micro-planning meetings. SIGNIFICANCE The Covid epidemiology in SL is not well known, but the possible new waves makes this intervention a high public health priority. USEFULNESS. The model is based on training, motivation, follow up and a very simple monetary allowance system based on performance. An online daily report available on smartphone was provided to follow up performances and manage allowances system. PROBLEM The objective was a donation of vaccines, but after a short assessment the issue changed to the need of supporting the local health staff. The goal shifted to train, give incentives for health workers, support to micro-planification and also to work on timely reporting to follow up the project results. QUESTIONS ANSWERED. Can support to microplanning be effective in enhancing vaccination numbers? Can monetary incentives to personnel based on performances enhance vaccination numbers? Can a setting approach (school, workplaces,..) enhance vaccinations numbers? RESULTS the numbers of vaccination Increased from an average of 5 per team by day in early December (after the refresh training) up to an average of 15 by day after the support to micro-planning, the monetary progressive incentives based on performance and the introduction of settings approach. Up to 85.000 doses was performed in 4 months.

Key messages

• Planning, performance based payement and training can enhance vaccination coverage.

• African countries can performe good vaccination programs if supported in organization and non only in vaccine donation.

Abstract 5270: Developing a predictive model for pancreatic neuroendocrine tumor metastatic potential: A multi-institutional analysis

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms that arise from cells in the islets of Langerhans, with surgical resection presently recommended for tumors &gt; 2cm. While many PNETs have the propensity to be indolent, some small tumors display aggressive features with early metastatic potential. We used machine learning to develop a predictive model of metastatic potential dependent upon the transcriptomic signature of primary PNET tissue. To build this model, RNA sequencing data was obtained from the primary tissue of 96 surgically-resected PNETs from various institutions. Two cohorts were generated with equally balanced metastatic PNET composition (15 (32.6%) vs. 13 (26.5%), p=0.52). A differential gene expression analysis identified 20 concordantly differentially expressed genes associated with metastatic status between the two cohorts. Unsupervised surrogate variable analysis estimated and adjusted for significant sources of variation not related to metastatic potential and mitigated unwanted noise and batch effects. A gene set enrichment analysis identified an additional 29 genes that most frequently contributed to the enriched biologic pathways extrapolated from the sequencing data. Log transformed, batch corrected TPM values for these 49 genes were combined with an additional 10 clinically-relevant genes, including ARX and PDX1, that are known to contribute to PNET signatures or oncogenesis. The datasets were subsequently randomized in a 1:1 ratio and informative features with respect to metastatic status were identified utilizing a Boruta algorithm, with a priori exclusion of highly-correlative genes and those that displayed near zero variance. Nine genes, including AURKA, ARX, CDCA8, CPB2, MYT1L, NDC80, PAPPA2, SFMBT1 and ZPLD1, were identified as sufficient to classify the localized or metastatic outcome. Distributed random forests (DRF), generalized linear models (GLM), gradient boosting machines (GBM) and extreme gradient boosting (XGBoost) models were trained utilizing these 9 genes. Training ROC ranged from 0.92 for DRF to 1 for XGboost. When applied to 47 independent validation samples, the testing sensitivity ranged from 75% for DRF to 94% for GBM; specificity ranged from 84% for DRF to 94% to XGboost and GLM; positive predictive value ranged from 72% for DRF to 86% for GLM; negative predictive value ranged from 88% for GLM to 97% to GBM. The degree of predictive agreement between models ranged from 64% to 91%. Taken together, we have developed a highly sensitive predictive model of the metastatic PNET phenotype that is based on expression of nine genes. Its application as a guide for management should be studied prospectively in patients with newly diagnosed PNETs.

Citation Format: Jacques A. Greenberg, Nikolay A. Ivanov, Yajas Shah, Scott Kulm, Jelani Williams, Catherine G. Tran, Theresa Scognamiglio, Yeon Joo Lee, Caitlin E. Egan, Irene M. Min, Rasa Zarnegar, James Howe, Xavier Keutgen, Thomas J. Fahey, Olivier Elemento, Brendan M. Finnerty. Developing a predictive model for pancreatic neuroendocrine tumor metastatic potential: A multi-institutional analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5270.

Abstract 6196: Fanconi anemia pathway deficiency drives copy number variation in squamous cell carcinoma

Fanconi anemia (FA), a model syndrome of genome instability, is caused by a deficiency in DNA interstrand crosslink (ICL) repair resulting in chromosome breakage. The FA repair pathway comprises at least 22 FANC proteins including BRCA1 and BRCA2 and protects against carcinogenic endogenous and exogenous aldehydes. Individuals with FA are hundreds to thousands-fold more likely to develop head and neck (HNSCC), esophageal and anogenital squamous cell carcinomas (SCCs) with a median onset age of 31 years. The aggressive nature of these tumors and poor patient tolerance of platinum and radiation-based therapy have been associated with short survival in FA. Molecular studies of SCCs from individuals with FA (FA SCCs) have been limited, and it is unclear how they relate to sporadic HNSCCs primarily driven by tobacco and alcohol exposure or human papillomavirus (HPV) infection. Here, by sequencing FA SCCs, we demonstrate that the primary genomic signature of FA-deficiency is the presence of a high number of structural variants (SVs). SVs are enriched for small deletions, unbalanced translocations, and fold-back inversions that arise in the context of TP53 loss. The SV breakpoints preferentially localize to early replicating regions, common fragile sites, tandem repeats, and SINE elements. SVs are often connected forming complex rearrangements. Resultant genomic instability underlies elevated copy number alteration (CNA) rates of key HNSCC-associated genes, including PIK3CA, MYC, CSMD1, PTPRD, YAP1, MXD4, and EGFR. In contrast to sporadic HNSCC, we find no evidence of HPV infection in FA HNSCC, although positive cases were identified in gynecologic tumors. A murine allograft model of FA pathway-deficient SCC was enriched in SVs, exhibited dramatic tumor growth advantage, more rapid epithelial-to-mesenchymal transition, and enhanced autonomous inflammatory signaling when compared to an FA pathway-proficient model. In light of the protective role of the FA pathway against SV formation uncovered here, and recent findings of FA pathway insufficiency in the setting of increased formaldehyde load resulting in hematopoietic stem cell failure and carcinogenesis, we propose that high copy-number instability in sporadic HNSCC may result from functional overload of the FA pathway by endogenous and exogenous DNA crosslinking agents. Our work lays the foundation for improved FA patient treatment and demonstrates that FA SCC is a powerful model to study tumorigenesis resulting from DNA crosslinking damage.

Citation Format: Andrew L. Webster, Mathijs A. Sanders, Krupa Patel, Ralf Dietrich, Raymond J. Noonan, Francis P. Lach, Ryan R. White, Audrey M. Goldfarb, Kevin Hadi, Matthew M. Edwards, Frank X. Donovan, Moonjung Jung, Sunandini Sridhar, Olivier Fedrigo, Huasong Tian, Joel Rosiene, Thomas Heineman, Jennifer Kennedy, Lorenzo Bean, Rasim O. Rosti, Rebecca Tryon, Ashlyn-Maree Gonzalez, Allana Rosenberg, Ji-Dung Luo, Thomas Carrol, Eunike Velleuer, Jeff C. Rastatter, Susanne I. Wells, Jordi Surrallés, Grover Bagby, Margaret L. MacMillan, John E. Wagner, Maria Cancio, Farid Boulad, Theresa Scognamiglio, Roger Vaughan, Amnon Koren, Marcin Imielinski, Settara Chandrasekharappa, Arleen D. Auerbach, Bhuvanesh Singh, David Kutler, Peter J. Campbell, Agata Smogorzewska. Fanconi anemia pathway deficiency drives copy number variation in squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6196.

Inhibition of FGF receptor blocks adaptive resistance to RET inhibition in CCDC6-RET-rearranged thyroid cancer

Genetic alterations in RET lead to activation of ERK and AKT signaling and are associated with hereditary and sporadic thyroid cancer and lung cancer. Highly selective RET inhibitors have recently entered clinical use after demonstrating efficacy in treating patients with diverse tumor types harboring RET gene rearrangements or activating mutations. In order to understand resistance mechanisms arising after treatment with RET inhibitors, we performed a comprehensive molecular and genomic analysis of a patient with RET-rearranged thyroid cancer. Using a combination of drug screening and proteomic and biochemical profiling, we identified an adaptive resistance to RET inhibitors that reactivates ERK signaling within hours of drug exposure. We found that activation of FGFR signaling is a mechanism of adaptive resistance to RET inhibitors that activates ERK signaling. Combined inhibition of FGFR and RET prevented the development of adaptive resistance to RET inhibitors, reduced cell viability, and decreased tumor growth in cellular and animal models of CCDC6-RET-rearranged thyroid cancer.

Phase I study of AIC100 in relapsed and/or refractory advanced thyroid cancer and anaplastic thyroid cancer

6093

Background: ICAM-1 is a cell surface glycoprotein that is typically expressed on endothelial cells and immune cells and a ligand for LFA-1 integrin. It is also overexpressed in several malignancies, in particular anaplastic and advanced thyroid cancer. We designed an affinity tuned ICAM-1-directed CAR T cell (micromolar affinity) that preferentially binds overexpressed ICAM-1 on tumor cells and spares normal cells. The CAR T cells also express somatostatin receptor 2 (SSTR2), which allows tracking of CAR T cells in vivo via DOTATATE PET/CT scan. Murine studies showed excellent responses in ICAM-1 expressing thyroid cancer without significant toxicities. We are conducting a first-in-human phase 1 clinical trial to evaluate the feasibility, safety and preliminary efficacy of ICAM-1 in patients with relapsed/refractory thyroid cancer or anaplastic thyroid cancer who are BRAF wild-type, or BRAF mutated after failure of BRAF specific therapy (NCT04420754). Methods: This is a dose-escalation study with modified toxicity probability interval design and cohorts of 3 Patients. Patients receive a single dose of 1x 107 (Cohort 1), 1 x 108 (Cohort 2) or 5 x 108 (Cohort 3) ICAM-1 CAR T cells after FLU/CY lymphodepleting (LD) chemotherapy. Additional CAR T infusion is allowed if patients achieve partial response or stable disease. Whole-body Fluorodeoxyglucose (FDG) and DOTATATE PET/CT is used to stage tumor and track CAR T cells in vivo, respectively. Results: All ICAM-1 CAR T infusion products met target transduction efficiency. Two patients with progressive anaplastic thyroid cancer received ICAM-1 CAR T therapy at dose-level I. Evaluation of CAR T cellular kinetics demonstrated transient peripheral blood CAR T cell expansion. One patient developed grade 1 cytokine release syndrome (CRS) with fever. Several tumor lesions from this patient showed DOTATATE avidity, indicating CAR T homing to the tumor, concomitant with decrease in FDG avidity, suggesting biological activity at ̃2 weeks post CAR T infusion. DOTATATE avidity at 2 weeks post CAR T infusion also appeared to match that of CAR T abundance in the blood. Updated results on additional patients and cohorts will be presented. Conclusions: Adoptive cellular therapy with ICAM-1 directed CAR T is safe and feasible at dose level 1 in patients with anaplastic thyroid cancer. DOTATATE PET allows visualization of expansion and homing of SSTR2 expressing CAR T cells, while concomitant FDG PET permits correlation with biological activity. Clinical trial information: NCT04420754.

RET Fusion-Positive Papillary Thyroid Cancers are Associated with a More Aggressive Phenotype

BACKGROUND

It is unclear if different genetic drivers in papillary thyroid cancer (PTC) confer different phenotypic tumor behavior leading to more aggressive disease. We hypothesized that RET-driven cancers are more aggressive.

PATIENTS AND METHODS

We reviewed records of consecutive patients treated for newly diagnosed PTC at this single institution from 2015 to 2016. Tumor samples from these patients were genotyped to identify RET-translocated, BRAFV600E mutant, and HRAS, KRAS, and NRAS mutant tumors. Patient demographic, clinicopathologic, and outcomes data were compared to identify genotype-specific patterns of disease.

RESULTS

Of the 327 patients who underwent initial surgery for PTC during the study period, 192 (58.7%) had BRAFV600E mutant tumors (BRAF), 14 (4.3%) had RET-rearranged tumors (RET), 46 (14.1%) had RAS mutant tumors (RAS), and 75 (22.9%) had BRAF, RET, and RAS wildtype tumors. RET-driven tumors were more likely to have extrathyroidal extension (50.0% versus 27.0% for BRAF and 2.2% for RAS, P < 0.001), multifocal disease (85.7% versus 60.3%, and 44.4%, respectively, P = 0.017), and distant metastases (14.3% versus 1.1%, and 0%, respectively, P = 0.019). RET and BRAF patients also had worse disease-free survival than RAS patients (Kaplan-Meier log rank, P = 0.027).

CONCLUSIONS

Patients with RET-driven PTCs had higher rates of extrathyroidal extension, multifocal disease, and distant metastases than patients whose tumors had BRAFV600E or RAS mutations. Patients with RET-rearranged tumors had similar disease-free survival to patients with BRAFV600E mutant tumors. RET rearrangement may confer an aggressive phenotype in PTC.

NR4A3 Immunostain Is a Highly Sensitive and Specific Marker for Acinic Cell Carcinoma in Cytologic and Surgical Specimens

OBJECTIVES

Salivary gland acinic cell carcinoma (AciCC) has recognizable cytomorphologic features that can overlap with benign and malignant entities, creating a diagnostic challenge. AciCC harbors a t(4;9) translocation increasing nuclear receptor subfamily 4 group A member 3 (NR4A3) expression, detectable by immunohistochemistry (IHC) on surgical resection (SR). NR4A3 IHC cytology data are limited. Here, we examine NR4A3 IHC on smears, cell blocks (CBs), and SRs of AciCC and its mimickers.

METHODS

Our cohort comprised AciCC (including high-grade transformation), secretory carcinoma, mucoepidermoid carcinoma (MEC), Warthin tumor, pleomorphic adenoma (PA), cellular PA, carcinoma ex-PA, oncocytic carcinoma, oncocytoma, and nodular oncocytosis. NR4A3 IHC (Santa Cruz Biotechnology and Origene antibodies) was positive if more than 5% tumor cells showed nuclear staining.

RESULTS

Among CBs, 90% of AciCC cases and none of the mimickers expressed NR4A3. Among SRs, 100% of AciCC cases showed diffuse NR4A3, whereas one high-grade MEC expressed focal NR4A3. Concordance was 95% with two antibody clones. Sensitivity, specificity, positive predictive value, and negative predictive value were 90%, 100%, 100%, and 94.7% for CBs and 100%, 98.8%, 92.3%, and 100% for SRs, respectively. NR4A3 immunostaining was demonstrable on smears from an AciCC case.

CONCLUSIONS

NR4A3 IHC can be a robust diagnostic tool to identify AciCC, especially for cytology specimens.

EZH2 Knockout in Oral Cavity Basal Epithelia Causes More Invasive Squamous Cell Carcinomas

Oral squamous cell carcinoma (oral SCC) is an aggressive disease and despite intensive treatments, 5-year survival rates for patients have remained low in the last 20 years. Enhancer of zeste homolog 2 (EZH2), part of polycomb repressive complex 2 (PRC2), is highly expressed in human oral SCC samples and cell lines and has been associated with greater epithelia-to-mesenchymal transition (EMT), invasion, and metastasis. Here we developed a tamoxifen-regulated, transgenic mouse line (KcEZH2) in which EZH2 is selectively knocked out (KO) in some tongue epithelial basal stem cells (SCs) in adult mice. EZH2 KO SCs do not show the H3K27me3 mark, as assessed by double-label immunofluorescence. We used this mouse line to assess EZH2 actions during oral tumorigenesis with our immunocompetent 4-nitroquinoline 1-oxide (4-NQO) model of oral SCC. We report that higher percentages of mice with invasive SCCs and high-grade neoplastic lesions are observed in mice containing EZH2 KO SCs (KcEZH2-2TΔ and KcEZH2-5TΔ mice). Moreover, EZH2 expression does not correlate with the expression of markers of invasive SCCs. Finally, EZH2 KO cells that are E-cadherin+ are present at invasion fronts infiltrating underlying muscle tissue. Our findings indicate that the knockout of EZH2 in basal SCs of tongue epithelia results in more aggressive carcinomas, and this should be considered when targeting EZH2 as a therapeutic strategy.

CSPG4 Is a Potential Therapeutic Target in Anaplastic Thyroid Cancer

Background: Anaplastic thyroid cancer (ATC) is a rare cancer with poor prognosis and few treatment options. The objective of this study was to investigate new immune-associated therapeutic targets by identifying ATC-derived, human leukocyte antigen (HLA) class II-presenting peptides. One protein that generated multiple peptides in ATC was chondroitin sulfate-proteoglycan-4 (CSPG4), a transmembrane proteoglycan with increased expression in multiple aggressive cancers, but not yet investigated in ATC. Methods: We applied autologous peripheral blood T cells to ATC patient-derived xenografted mice to examine whether ATC induces a tumor-specific T cell response. We then identified peptide antigens eluted from the HLA-DQ complex in ATC patient-derived cells using mass spectrometry, detecting abundant CSPG4-derived peptides specific to the ATC sample. Next, we analyzed the surface expression level of CSPG4 in thyroid cancer cell lines and primary cell culture using flow cytometry. In addition, we used immunohistochemistry to compare the expression level and localization of the CSPG4 protein in ATC, papillary thyroid cancer, and normal thyroid tissue. We then investigated the correlation between CSPG4 expression and clinicopathological features of patients with thyroid cancer. Results: We found that ATC tissue had a high level of HLA-DQ expression and that the patient's CD4⁺ T cells showed activation when exposed to ATC. By eluting the HLA-DQ complex of ATC tissue, we found that CSPG4 generated one of the most abundant and specific peptides. CSPG4 expression at the cell surface of thyroid cancer was also significantly high when determined by flow cytometry, with the majority of ATC cell lines exhibiting ∼10-fold higher mean fluorescence intensity. Furthermore, most ATC patient cases expressed CSPG4 in the cytoplasm or membrane of the tumor cells. CSPG4 expression was correlated with tumor size, extrathyroidal extension, and intercellular adhesion molecule-1 (ICAM-1) circumferential expression. CSPG4 mRNA overexpression was associated with worse overall survival in patients with ATC and poorly differentiated thyroid cancer. Conclusions: CSPG4 expression is significantly elevated in aggressive thyroid cancers, with a strong correlation with a poor prognosis. The vast number of HLA-DQ eluted CSPG4 peptides was identified in ATC, demonstrating the potential of CSPG4 as a novel immunotherapeutic target for ATC.

Abstract 1434: Uncovering the mechanism of adaptive resistance to RET inhibitors in RET rearranged thyroid cancer

Kinase inhibitors are a critical tool for cancer treatment, but their efficacy is limited by resistance mechanisms. In thyroid and lung cancer RET gene rearrangements result in constitutive MAPK pathway activation and drive malignancy. While treatment with new selective RET inhibitors has been associated with significant clinical responses, a majority of patients experience a partial response or disease stabilization as their best clinical outcome. Resistance to RET inhibitors has emerged as a clinical problem requiring new treatment strategies. Using a combination of drug screening, proteomic, and biochemical profiling we identified a strategy to overcome adaptive resistance to RET inhibitors in human thyroid cancer cell lines and vertebrate animal models. The identification of alternative signaling pathways that reactivates ERK signaling as a mechanism of resistance to RET inhibitors provides an opportunity to anticipate resistance to selective RET inhibitors and use combination therapy that leads to more significant and durable anti-tumor responses in patients with RET rearranged cancers.

Citation Format: Renuka Raman, Jacques Villefranc, Timothy Ullmann, Jessica Thiesmeyer, Viviana Anelli, Chantal Pauli, Rohan Bareja, Kenneth Wha Eng, Princesca Dorsaint, David Wilkes, Shaham Beg, Reid Shaw, Michael Churchill, Naveen Gumpeni, Theresa Scognamiglio, Mark Rubin, Carla Grandori, Juan Mosquera, Juan Mosquera, Juan Mosquera, Noah Dephoure, Andrea Sboner, Olivier Elemento, Yariv Houvras. Uncovering the mechanism of adaptive resistance to RET inhibitors in RET rearranged thyroid cancer [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 1434.

Performance Characteristics of a Targeted Sequencing Platform for Simultaneous Detection of Single Nucleotide Variants, Insertions/Deletions, Copy Number Alterations, and Gene Fusions in Cancer Genome

CONTEXT.—

An increasing number of molecular laboratories are implementing next-generation sequencing platforms to identify clinically actionable and relevant genomic alterations for precision oncology.

OBJECTIVE.—

To describe the validation studies as per New York State-Department of Health (NYS-DOH) guidelines for the Oncomine Comprehensive Panel v2, which was originally tailored to the National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH) trial.

DESIGN.—

Accuracy, precision, and reproducibility were investigated by using 130 DNA and 18 RNA samples from cytology cell blocks; formalin-fixed, paraffin-embedded tissues; and frozen samples. Analytic sensitivity and specificity were tested by using ATCC and HapMap cell lines.

RESULTS.—

High accuracy and precision/reproducibility were observed for single nucleotide variants and insertion/deletions. We also share our experience in the detection of gene fusions and copy number alterations from an amplicon-based sequencing platform. After sequencing analysis, variant annotation and report generation were performed by using the institutional knowledgebase.

CONCLUSIONS.—

This study serves as an example for validating a comprehensive targeted next-generation sequencing assay with both DNASeq and RNASeq components for NYS-DOH.

Mutations in long-lived epithelial stem cells and their clonal progeny in pre-malignant lesions and in oral squamous cell carcinoma

Oral squamous cell carcinomas (OSCCs) are the most common cancers of the oral cavity, but the molecular mechanisms driving OSCC carcinogenesis remain unclear. Our group previously established a murine OSCC model based on a 10-week carcinogen [4-nitroquinoline 1-oxide (4-NQO)] treatment. Here we used K14CreERTAM;Rosa26LacZ mice to perform lineage tracing to delineate the mutational profiles in clonal cell populations resulting from single, long-lived epithelial stem cells, here called LacZ+ stem cell clones (LSCCs). Using laser-capture microdissection, we examined mutational changes in LSCCs immediately after the 10-week 4-NQO treatment and >17 weeks after 4-NQO treatment. We found a 1.8-fold ±0.4 (P = 0.009) increase in single-nucleotide variants and insertions/deletions (indels) in tumor compared with pre-neoplastic LSCCs. The percentages of indels and of loss of heterozygosity events were 1.3-fold±0.3 (P = 0.02) and 2.2-fold±0.7 (P = 0.08) higher in pre-neoplastic compared with tumor LSCCs. Mutations in cell adhesion- and development-associated genes occurred in 83% of the tumor LSCCs. Frequently mutated genes in tumor LSCCs were involved in planar cell polarity (Celsr1, Fat4) or development (Notch1). Chromosomal amplifications in 50% of the tumor LSCCs occurred in epidermal growth factor receptor, phosphoinositide 3-kinase and cell adhesion pathways. All pre-neoplastic and tumor LSCCs were characterized by key smoking-associated changes also observed in human OSCC, C>A and G>T. DeconstructSigs analysis identified smoking and head and neck cancer as the most frequent mutational signatures in pre-neoplastic and tumor LSCCs. Thus, this model recapitulates a smoking-associated mutational profile also observed in humans and illustrates the role of LSCCs in early carcinogenesis and OSCCs.

PD1 Blockade Enhances ICAM1-Directed CAR T Therapeutic Efficacy in Advanced Thyroid Cancer

PURPOSE

Advanced thyroid cancers, including poorly differentiated and anaplastic thyroid cancer (ATC), are lethal malignancies with limited treatment options. The majority of patients with ATC have responded poorly to programmed death 1 (PD1) blockade in early clinical trials. There is a need to explore new treatment options.

EXPERIMENTAL DESIGN

We examined the expression of PD-L1 (a ligand of PD1) and intercellular adhesion molecule 1 (ICAM1) in thyroid tumors and ATC cell lines, and investigated the PD1 expression level in peripheral T cells of patients with thyroid cancer. Next, we studied the tumor-targeting efficacy and T-cell dynamics of monotherapy and combination treatments of ICAM1-targeting chimeric antigen receptor (CAR) T cells and anti-PD1 antibody in a xenograft model of ATC.

RESULTS

Advanced thyroid cancers were associated with increased expression of both ICAM1 and PD-L1 in tumors, and elevated PD1 expression in CD8⁺ T cells of circulating blood. The expression of ICAM1 and PD-L1 in ATC lines was regulated by the IFNγ-JAK2 signaling pathway. ICAM1-targeted CAR T cells, produced from either healthy donor or patient T cells, in combination with PD1 blockade demonstrated an improved ability to eradicate ICAM1-expressing target tumor cells compared with CAR T treatment alone. PD1 blockade facilitated clearance of PD-L1 high tumor colonies and curtailed excessive CAR T expansion, resulting in rapid tumor clearance and prolonged survival in a mouse model.

CONCLUSIONS

Targeting two IFNγ-inducible, tumor-associated antigens-ICAM1 and PD-L1-in a complementary manner might be an effective treatment strategy to control advanced thyroid cancers in vivo.

Characterizing and classifying neuroendocrine neoplasms through microRNA sequencing and data mining

Neuroendocrine neoplasms (NENs) are clinically diverse and incompletely characterized cancers that are challenging to classify. MicroRNAs (miRNAs) are small regulatory RNAs that can be used to classify cancers. Recently, a morphology-based classification framework for evaluating NENs from different anatomical sites was proposed by experts, with the requirement of improved molecular data integration. Here, we compiled 378 miRNA expression profiles to examine NEN classification through comprehensive miRNA profiling and data mining. Following data preprocessing, our final study cohort included 221 NEN and 114 non-NEN samples, representing 15 NEN pathological types and 5 site-matched non-NEN control groups. Unsupervised hierarchical clustering of miRNA expression profiles clearly separated NENs from non-NENs. Comparative analyses showed that miR-375 and miR-7 expression is substantially higher in NEN cases than non-NEN controls. Correlation analyses showed that NENs from diverse anatomical sites have convergent miRNA expression programs, likely reflecting morphological and functional similarities. Using machine learning approaches, we identified 17 miRNAs to discriminate 15 NEN pathological types and subsequently constructed a multilayer classifier, correctly identifying 217 (98%) of 221 samples and overturning one histological diagnosis. Through our research, we have identified common and type-specific miRNA tissue markers and constructed an accurate miRNA-based classifier, advancing our understanding of NEN diversity.

Preanalytic variables in quality and quantity of nucleic acids extracted from FNA specimens of thyroid gland nodules collected in CytoLyt: Cellularity and storage time

BACKGROUND

Morphologic and genetic analysis of thyroid nodules may be performed from a single vial. Preanalytic variables that affect nucleic acid extracted from a single vial are evaluated.

METHODS

Thyroid fine-needle aspiration (FNA) specimens collected in CytoLyt were evaluated. A ThinPrep slide was prepared. Extracted nucleic acids were analyzed using Oncomine Comprehensive Panel, version 2, after Ion AmpliSeq library preparation. A pathologist and a cytotechnologist enumerated specimen cellularity.

RESULTS

Fifty-six samples were collected from 55 nodules in 53 patients. Bethesda category correlated with cellularity (P = .01), and storage time (median, 43 days; range, 7-77 days) was longer for specimens in categories II and III than for those in categories IV and VI (P = .01). The mean specimen DNA concentration was 4.5 ng/µL (range, 0-23.8 ng/µL), and 25 (45%) had concentrations >3.3 ng/µL. The mean specimen RNA concentration was 4.8 ng/µL (range, 0-42.4 ng/µL), and 31 (55%) had concentrations >1.4 ng/µL. Nucleic acid quantity increased with epithelial cellularity. Storage time weakly correlated with the quantity of extracted DNA, independent of cellularity, but not extracted RNA. Greater proportions of cell-free DNA and lesser proportions of long, intact RNA fragments were extracted from a subset of samples with longer storage time. Among 15 single nucleotide variants, the median mutant allelic fraction was 15.1%. One false-negative result was identified. Five specimens subsequently determined to harbor a genetic alteration failed quality metrics.

CONCLUSIONS

Cellularity and storage time affect the quantity and quality of nucleic acid extracted from thyroid FNA specimens collected in CytoLyt. Further investigation will serve to quantify the magnitude of such effects and to elucidate other contributing factors.

Doxycycline-induced exogenous Bmi-1 expression enhances tumor formation in a murine model of oral squamous cell carcinoma

B Cell-Specific Moloney Murine Leukemia Virus Integration Site 1 (Bmi-1, Bmi1), an epigenetic protein, is necessary for normal stem cell self-renewal in adult animals and for cancer stem cell (CSC) functions in adult animals. To elucidate the functions of Bmi-1 in the oral cavity we created a transgenic mouse line (KrTBmi-1) that expresses ectopic, Flag-tagged Bmi-1 in tongue basal epithelial stem cells only upon doxycycline (DOX) treatment. Genome wide transcriptomics and Ingenuity Pathway Analysis identified several pathways altered by exogenous Bmi-1 expression in the normal tongue epithelium, including EIF2 signaling (P value = 1.58 x 10^-49), mTOR signaling (P value = 2.45 x 10^-12), oxidative phosphorylation (P = 6.61 x 10^-3) and glutathione redox reactions I (P = 1.74 x 10^-2). Overall, our data indicate that ectopic Bmi-1 expression has an impact on normal tongue epithelial homeostasis. We then assessed the KrTBmi-1 mice in the 4-nitroquinoline 1-oxide (4-NQO) model of oral carcinogenesis. We found that 80% of mice expressing exogenous Bmi-1 (+DOX, +4-NQO KrTBmi-1; N = 10) developed tumors classified as grade 3 or higher, compared to 60% and 40% of mice expressing just endogenous Bmi-1 (+DOX, +4-NQO Kr and -DOX, +4-NQO KrTBmi-1 groups, respectively; N = 10/group; P value = <0.0001); and 30% of mice expressing ectopic Bmi-1 mice developed 20 or more lesions compared to 10% of mice expressing only endogenous Bmi-1 (P = .009). This demonstrates that exogenous Bmi-1 expression increases the susceptibility of mice to 4-NQO-induced oral carcinogenesis, strengthening the evidence for Bmi-1 as a therapeutic target in human oral squamous cell carcinoma.

Can cytology and the Thyroid Imaging, Reporting, and Data System (TI-RADS) identify noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) before surgery?

INTRODUCTION

In 2017, the American College of Radiology (ACR) created the Thyroid Imaging, Reporting, and Data System (TI-RADS) to select thyroid nodules for fine-needle aspiration (FNA). The objective of this study is to find out whether ACR TI-RADS is useful in triaging thyroid follicular cells with papillary-like nuclear features obtained by FNA to determine the extent of surgery.

MATERIAL AND METHODS

The grayscale ultrasound of 76 noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), 41 encapsulated (E), and 79 infiltrative (I) follicular variant (FV) of papillary thyroid carcinoma (PTC) were reviewed and assigned TI-RADS points and then suspicion levels.

RESULTS

Of the 39 tumors with high suspicion level, 32 were IFVPTC, and seven were EFVPTC. Of the 137 tumors with moderate suspicion level, 47 were IFVPTC, 34 were EFVPTC, and 56 were NIFTP. Of the 19 tumors with mild suspicion level, all were NIFTP. The only tumor with no suspicion was an NIFTP. IFVPTC had a significantly higher suspicion level than EFVPTC and NIFTP (P < 0.0001). The difference in suspicion level between EFVPTC and NIFTP is not statistically significant. None of the cases of NIFTP in the study had a high suspicion level.

CONCLUSIONS

The study demonstrates that cytology interpreted in the context of ACR TI-RADS suspicion levels can separate NIFTP from many IFVPTC and a few EFVPTC with overt invasion. PTC could be diagnosed in cytology if cells with papillary-like nuclear features derived from TR5 nodules. The nodules with TR4 or less that yield similar cells require surgical pathology to diagnose FVPTC with microscopic capsular or vascular invasions.

Abstract 4665: Lineage-tracing technology to understand the molecular events in a mouse model of tongue squamous cell carcinoma (SCC) carcinogenesis

Oral cavity squamous cell carcinomas (OCSCCs) account for over 450,000 cases per year worldwide, present a high metastatic potential, and have a survival rate ≤ 50%. There is a high incidence of OCSCC, but the mechanisms of carcinogenesis remain unclear. Therefore, the aim of this research was to delineate the mutational landscape in developing tumors and OCSCCs by combining a lineage tracing approach and a mouse model of tongue carcinogenesis, previously established by our group.

We used K14-CreERTAM; Rosa26LacZ mice, which allowed the long term basal stem cells of the epithelium to be permanently marked at the time of a two-day tamoxifen treatment. We then induced carcinogenesis by treating mice for 10 weeks with the carcinogen 4-nitroquinoline 1-oxide (4-NQO), which recapitulates key phenotypic and molecular features observed in human OCSCC. We performed Laser Capture Microdissection (LCM) to isolate and retrieve high-quality genomic DNA exclusively from each clone of permanently labeled, long-lived LacZ+ stem cells; each clone of cells arises from one LacZ+ stem cell. We then performed exome sequencing of 3 to 5 mice per group, sacrificed immediately after the 10-week treatment with 4-NQO (pre-neoplastic), and mice sacrificed &gt;19 weeks after the end of 4-NQO treatment (SCC). As a reference genome for alignment and germline mutation exclusion, we included 3 mice of the same genetic background that did not receive 4-NQO.

After 10 weeks of 4-NQO treatment the tongues were hyperplastic, with occasional necrosis and mild atypia, whereas all mice evaluated &gt;19 weeks post 4-NQO treatment showed tongue SCCs. The total numbers of somatic mutations and LOH (loss of heterozygosity) identified using the mutation calling tool VarScan were 75% (4615±2170 vs 1148±76) higher in SCC compared to pre-neoplastic tongue samples. Among the mutations predicted as high and moderate impact, the levels of SNVs (single nucleotide variants) vs. indels were similar between SCCs and pre-neoplastic samples, 98.4% and 96.5%, respectively. By detailed analysis of the mutation types we showed that the pre-neoplastic tissues exhibited a much higher proportion of LOH events than the SCCs, 34.4% and 7.6%, respectively. Some of the genes affected by LOH in pre-neoplastic tissues were identified as tumor suppressors. Our findings suggest that a predominance of LOH in pre-neoplastic tongue tissue may result in loss of tumor suppressor genes, potentially defining the early steps of carcinogenesis in tongue SCCs.

In conclusion, following the fate of long term tongue epithelial stem cells has allowed us to identify genomic perturbations occurring in the tongues of 4-NQO-treated mice and to find potential early biomarkers for OCSCC. Grant ID: R01CA205258; Funding Agency: NIH/NCI.

Citation Format: Marta Melis, Tuo Zhang, Theresa Scognamiglio, Lorraine J. Gudas. Lineage-tracing technology to understand the molecular events in a mouse model of tongue squamous cell carcinoma (SCC) carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4665.

UCHL1 loss alters the cell-cycle in metastatic pancreatic neuroendocrine tumors

Loss of ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) expression by CpG promoter hypermethylation is associated with metastasis in gastroenteropancreatic neuroendocrine tumors; however, the mechanism of how UCHL1 loss contributes to metastatic potential remains unclear. In this study, we first confirmed that loss of UCHL1 expression on immunohistochemistry was significantly associated with metastatic tumors in a translational pancreatic neuroendocrine tumor (PNET) cohort, with a sensitivity and specificity of 78% and 89%, respectively. To study the mechanism driving this aggressive phenotype, BON and QGP-1 metastatic PNET cell lines, which do not produce UCHL1, were stably transfected to re-express UCHL1. In vitro assays, RNA-sequencing, and reverse-phase protein array (RPPA) analyses were performed comparing empty-vector negative controls and UCHL1-expressing cell lines. UCHL1 re-expression is associated with lower anchorage-independent colony growth in BON cells, lower colony formation in QGP cells, and a higher percentage of cells in the G0/G1 cell-cycle phase in BON and QGP cells. On RPPA proteomic analysis, there was an upregulation of cell-cycle regulatory proteins CHK2 (1.2 fold change, p=0.004) and P21 (1.2 fold change, p=0.023) in BON cells expressing UCHL1; western blot confirmed upregulation of phosphorylated CHK2 and P21. There were no transcriptomic differences detected on RNA-Sequencing between empty-vector negative controls and UCHL1-expressing cell lines. In conclusion, UCHL1 loss correlates with metastatic potential in PNETs and its re-expression induces a less aggressive phenotype in vitro, in part by inducing cell-cycle arrest through post-translational regulation of phosphorylated CHK2. UCHL1 re-expression should be considered as a functional biomarker in detecting PNETs capable of metastasis.

Evaluating gastroenteropancreatic neuroendocrine tumors through microRNA sequencing

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can be challenging to evaluate histologically. MicroRNAs (miRNAs) are small RNA molecules that often are excellent biomarkers due to their abundance, cell-type and disease stage specificity and stability. To evaluate miRNAs as adjunct tissue markers for classifying and grading well-differentiated GEP-NETs, we generated and compared miRNA expression profiles from four pathological types of GEP-NETs. Using quantitative barcoded small RNA sequencing and state-of-the-art sequence annotation, we generated comprehensive miRNA expression profiles from archived pancreatic, ileal, appendiceal and rectal NETs. Following data preprocessing, we randomly assigned sample profiles to discovery (80%) and validation (20%) sets prior to data mining using machine-learning techniques. High expression analyses indicated that miR-375 was the most abundant individual miRNA and miRNA cistron in all samples. Leveraging prior knowledge that GEP-NET behavior is influenced by embryonic derivation, we developed a dual-layer hierarchical classifier for differentiating GEP-NET types. In the first layer, our classifier discriminated midgut (ileum, appendix) from non-midgut (rectum, pancreas) NETs based on miR-615 and -92b expression. In the second layer, our classifier discriminated ileal from appendiceal NETs based on miR-125b, -192 and -149 expression, and rectal from pancreatic NETs based on miR-429 and -487b expression. Our classifier achieved overall accuracies of 98.5% and 94.4% in discovery and validation sets, respectively. We also found provisional evidence that low- and intermediate-grade pancreatic NETs can be discriminated based on miR-328 expression. GEP-NETs can be reliably classified and potentially graded using a limited panel of miRNA markers, complementing morphological and immunohistochemistry-based approaches to histologic evaluation.

Expression of programmed death ligand 1 and 2 in adrenocortical cancer tissues: An exploratory study

BACKGROUND

Inhibition of the interaction of programmed death 1 with programmed death ligand 1 and 2 has been used successfully for treatment of multiple advanced cancers, but expression has not been studied in adrenocortical carcinoma. In this study, we investigated programmed death ligand 1 and 2 expression in adrenocortical carcinoma to determine the potential usefulness of checkpoint inhibitors in these malignant neoplasms.

METHODS

A total of 56 tissue samples from patients with adrenocortical carcinoma (34) and benign adrenal tissues (22) were identified. Immunohistochemistry was performed for programmed death ligand 1, programmed death ligand 2, and CD8 and scored for membranous staining on adrenal and stromal tissue according to the immunoreactive score and absolute percentage, respectively. Descriptive statistics, a Mann-Whitney U test, and Fisher exact tests were calculated.

RESULTS

In total, 15 adrenocortical carcinoma (44%) stained positive for programmed death ligand 2 and 1 adrenocortical carcinoma for programmed death ligand 1 (P = .03). Adrenocortical carcinoma samples were more likely to express programmed death ligand 2 on tumor cells or in stromal tissues than benign samples (OR = 2.3, P = .03). There was no relationship between programmed death ligand 2 and CD8 expression (P = .08). There were also no relationships between programmed death ligand 2 or CD8 expression and tumor characteristics.

CONCLUSION

Programmed death ligand 2, but not programmed death ligand 1, is expressed commonly in adrenocortical carcinoma samples. The utility of certain checkpoint inhibitors should, therefore, be evaluated in further studies.

CHL1 expression differentiates Hürthle cell carcinoma from benign Hürthle cell nodules

BACKGROUND AND OBJECTIVES

Hürthle cell carcinoma (HCC) is an unusual and relatively rare type of differentiated thyroid cancer. Currently, cytologic analysis of fine-needle aspiration biopsy is limited in distinguishing benign Hürthle cell neoplasms from malignant ones. The aim of this study was to determine whether differences in the expression of specific genes could differentiate HCC from benign Hürthle cell nodules by evaluating differential gene expression in Hürthle cell disease.

METHODS

Eighteen benign Hürthle cell nodules and seven HCC samples were analyzed by whole-transcriptome sequencing. Bioinformatics analysis was carried out to identify candidate differentially expressed genes. Expression of these candidate genes was re-examined by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was quantified by immunohistochemistry.

RESULTS

Close homolog of L1 (CHL1) was identified as overexpressed in HCC. CHL1 was found to have greater than 15-fold higher expression in fragments per kilobase million in HCC compared with benign Hurthle cell tumors. This was confirmed by qRT-PCR. Moreover, the immunoreactivity score of the CHL1 protein was significantly higher in HCC compared with benign Hürthle cell nodules.

CONCLUSIONS

CHL1 expression may represent a novel and useful prognostic biomarker to distinguish HCC from benign Hürthle cell disease.

Breast Tumor Resembling the Tall Cell Variant of Papillary Thyroid Carcinoma: Molecular Characterization by Next-Generation Sequencing and Histopathological Comparison With Tall Cell Papillary Carcinoma of Thyroid

Recent publications have brought attention to the histopathological, immunohistochemical, and molecular aspects of the rare breast tumor resembling the tall cell variant of papillary thyroid carcinoma (BrTC). Nine archived cases of this entity were retrieved, reviewed, and compared with randomly selected tall cell variants of papillary thyroid carcinoma (ThTC). Seven of the BrTC cases as well as 5 cases of solid papillary carcinoma of breast were analyzed by Oncomine next-generation sequencing. BrTC and ThTC were histologically distinguishable by the presence of solid architecture, luminal histiocytes, and reverse polarity in the former, and psammoma bodies, giant cells, and optically clear nuclei in the latter. Sequencing revealed IDH2 R172 single-nucleotide variants in all 7 BrTCs, 6 of which had concurrent PIK3CA mutations. None of the conventional solid papillary carcinomas demonstrated IDH2 mutation. BrTC bears superficial resemblance to other papillary tumors but is unique in terms of histology and molecular profile.

Prognostic Implications of Gadolinium Enhancement of Skull Base Chordomas

BACKGROUND AND PURPOSE

Skull base chordomas often demonstrate variable MR imaging characteristics, and there has been limited prior research investigating the potential clinical relevance of this variability. The purpose of this retrospective study was to assess the prognostic implications of signal intensity on standard imaging techniques for the biologic behavior of skull base chordomas.

MATERIALS AND METHODS

Medical records were retrospectively reviewed for 22 patients with pathologically confirmed skull base chordomas. Clinical data were recorded, including the degree of surgical resection, the presence or absence of radiation therapy, and time to progression/recurrence of the tumor or time without progression/recurrence of the tumor following initial treatment. Pretreatment imaging was reviewed for the presence or absence of enhancement and the T2 signal characteristics. Tumor-to-brain stem signal intensity ratios on T2, precontrast T1, and postcontrast T1 spin-echo sequences were also calculated. Statistical analysis was then performed to assess correlations between imaging characteristics and tumor progression/recurrence.

RESULTS

Progression/recurrence of skull base chordomas was seen following surgical resection in 11 of 14 (78.6%) patients with enhancing tumors and in zero of 8 patients with nonenhancing tumors. There was a statistically significant correlation between skull base chordoma enhancement and subsequent tumor progression/recurrence (P < .001), which remained significant after controlling for differences in treatment strategy (P < .001). There was also a correlation between postcontrast T1 signal intensity (as measured by postcontrast T1 tumor-to-brain stem signal intensity ratios) and recurrence/progression (P = .02). While T2 signal intensity was higher in patients without tumor progression (median tumor-to-brain stem signal intensity ratios on T2 = 2.27) than in those with progression (median tumor-to-brain stem signal intensity ratios on T2 = 1.78), this association was not significant (P = .12).

CONCLUSIONS

Enhancement of skull base chordomas is a risk factor for tumor progression/recurrence following surgical resection.

Protein Expression of PTTG1 as a Diagnostic Biomarker in Adrenocortical Carcinoma

BACKGROUND

Adrenocortical carcinoma (ACC) has a poor prognosis and there is an unmet clinical need for biomarkers to improve both diagnostic and prognostic assessment. Pituitary-tumor transforming gene (PTTG1) has been shown to modulate cancer invasiveness and response to therapy. The potential role of PTTG1 protein levels in ACC has not been previously addressed. We assessed whether increased nuclear protein expression of PTTG1 distinguished ACCs from adrenocortical adenomas (ACAs).

METHODS

Patients with ACC or ACA were identified from prospective tissue banks at two independent institutions. Two tissue microarrays (TMAs) consisting of adrenal specimens from 131 patients were constructed and clinically annotated. Immunohistochemical analysis for PTTG1 and Ki-67 was performed on each TMA.

RESULTS

TMA-1 (n = 80) contained 20 normal adrenals, 20 ACAs, and 40 ACCs, and the validation, TMA-2 (n = 51), consisted of 10 normal adrenals, 14 ACAs, and 27 ACCs. On TMA-1, nuclear staining of PTTG1 was detected in 12 (31%) ACC specimens, while all ACAs and normal adrenal glands were negative for PTTG1. On TMA-2, 20 (74%) of the ACC tumors demonstrated PTTG1 nuclear staining of PTTG1, and 13 (93%) ACA and 4 (44%) normal adrenal glands were negative for PTTG1. ACC tumors with increased PTTG1 protein staining had a significantly higher Ki-67 index (p < 0.001) than those with lower levels of PTTG1.

CONCLUSIONS

Increased nuclear protein expression of PTTG1 was observed in malignant adrenal tumors. PTTG1 correlated with Ki-67 in two independent TMAs. PTTG1 is a promising biologic marker in the evaluation of adrenal tumors.

STMN1 is Overexpressed in Adrenocortical Carcinoma and Promotes a More Aggressive Phenotype In Vitro

BACKGROUND

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with a poor prognosis and few therapeutic options. Stathmin1 (STMN1) is a cytosolic protein involved in microtubule dynamics through inhibition of tubulin polymerization and promotion of microtubule depolymerization, which has been implicated in carcinogenesis and aggressive behavior in multiple epithelial malignancies. We aimed to evaluate expression of STMN1 in ACC and to elucidate how this may contribute to its malignant phenotype.

METHODS

STMN1 was identified by RNA sequencing as a highly differentially expressed gene in human ACC samples compared with benign adrenal tumors. Expression was confirmed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), Western blot, and immunohistochemical (IHC) staining of a tissue microarray (TMA) from two independent cohorts. The biologic relevance of STMN1 was investigated in NCI-H295R cells by lentivirus-mediated silencing.

RESULTS

Differential gene expression demonstrated an eightfold increase in STMN1 messenger RNA (mRNA) in malignant compared with benign adrenal tissue. IHC showed significantly higher expression of STMN1 protein in ACC compared with normal and benign tissues. STMN1 knockdown in an ACC cell line resulted in decreased cell viability, cell-cycle arrest at G₀/G₁, and increased apoptosis in serum-starved conditions compared with scramble short hairpin RNA (shRNA) controls. STMN1 knockdown also decreased migration, invasion, and anchorage-independent growth compared with controls.

CONCLUSIONS

STMN1 is overexpressed in human ACC samples, and knockdown of this target in vitro resulted in a less aggressive phenotype of ACC, particularly under serum-starved conditions. Further study is needed to investigate the feasibility of interfering with STMN1 as a potential therapeutic target.

Well-Differentiated Thyroid Cancer Neovasculature Expresses Prostate-Specific Membrane Antigen-a Possible Novel Therapeutic Target

Prostate-specific membrane antigen (PSMA), a type II transmembrane glycoprotein receptor, is highly expressed in prostate cancer and in the tumor neovasculature of colon, breast, and adrenocortical tumors. Here, we analyzed PSMA expression in the neovasculature of various thyroid cancer subtypes and assessed whether PSMA expression is correlated with aggressive behavior. From a prospectively maintained database, we evaluated 91 samples from 68 patients, including 37 primary differentiated thyroid cancers (DTCs) [11 classic papillary (cPTC), 9 follicular-variant (FvPTC), 11 follicular (FTC), 6 radioactive iodine-refractory (RAIR)], 5 anaplastic (ATC) carcinomas, 9 distant and 12 lymph node metastases, 21 benign thyroid nodules, and 7 normal thyroid specimens. Formalin-fixed paraffin-embedded tissue blocks were immunostained for vascular endothelial marker CD31 and PSMA with proper controls. PSMA expression was not detected in normal thyroid tissue. DTC tumors demonstrated a significantly higher PSMA expression, in regard to both intensity and percentage of vessels stained, than benign tumors (p < 0.001). Among the histologic subtypes, cPTC, FTC, and RAIR carcinomas demonstrated the highest percent of moderate to strong PSMA staining. PSMA expression was seen more frequently in specimens from distant metastases (100%) compared with specimens from only lymph node metastases (67%). PSMA is significantly overexpressed in the neovasculature of DTCs compared with normal and benign thyroid nodules specifically with increased expression in RAIR carcinomas and distant metastases. PSMA should be further explored as a novel therapeutic target for metastatic and RAIR carcinomas.

CAR T Therapy Targeting ICAM-1 Eliminates Advanced Human Thyroid Tumors

Purpose: Poorly differentiated thyroid cancer and anaplastic thyroid cancer (ATC) are rare yet lethal malignancies with limited treatment options. Many malignant tumors, including papillary thyroid cancer (PTC) and ATC, are associated with increased expression of ICAM-1, providing a rationale for utilizing ICAM-1-targeting agents for the treatment of aggressive cancer. We developed a third-generation chimeric antigen receptor (CAR) targeting ICAM-1 to leverage adoptive T-cell therapy as a new treatment modality.Experimental Design: ICAM-1 CAR T cells were applied to multiple malignant and nonmalignant target cells to investigate specific target cell death and "off-tumor" toxicity in vitroIn vivo therapeutic efficacy of ICAM-1 CAR T cells was examined in ATC mouse models established from a cell line and patient-derived tumors that rapidly develop systemic metastases.Results: ICAM-1 CAR T cells demonstrated robust and specific killing of PTC and ATC cell lines in vitro Interestingly, although certain ATC cell lines showed heterogeneous levels of ICAM-1 expression, addition of cytotoxic CAR T cells induced increased ICAM-1 expression such that all cell lines became targetable. In mice with systemic ATC, a single administration of ICAM-1 CAR T cells mediated profound tumor killing that resulted in long-term remission and significantly improved survival. Patient-derived ATC cells overexpressed ICAM-1 and were largely eliminated by autologous ICAM-1 CAR T cells in vitro and in animal models.Conclusions: Our findings are the first demonstration of CAR T therapy against both a metastatic, thyroid cancer cell line and advanced ATC patient-derived tumors that exhibit dramatic therapeutic efficacy and survival benefit in animal studies. Clin Cancer Res; 23(24); 7569-83. ©2017 AACR.

A Precious Diagnostic "Pearl": The Necklace Pattern in Germ Cell Tumors of the Testis

Diffuse embryoma is a rare pattern of nonseminomatous germ cell tumor of the testis originally described in 1983. We report a case with this predominant pattern in an 18-year-old male with a painless palpable testicular mass. Although it is relatively common to see a diffuse embryoma pattern focally in mixed nonseminomatous germ cell tumors of the testis, it is rarely the predominant pattern and can represent a diagnostic pitfall on routine hematoxylin and eosin stain. We emphasize the importance of recognizing the individual components within the diffuse embryoma pattern, review the literature, and briefly discuss the ancillary immunohistochemical stains that may be utilized to help support the diagnosis.