Papillary Thyroid Carcinoma Cohort Research Articles

BRAF-induced EHF expression affects TERT in aggressive papillary thyroid cancer.

BRAFV600E and TERT promoter mutations in papillary thyroid carcinoma (PTC) have a synergistic effect on prognosis. This effect is believed to arise from MAPK activation triggered by BRAFV600E, leading to the upregulation of ETS transcription factors that bind to the mutant TERT promoter. To explore the role of ETS factors in relation to clinical features, BRAFV600E and TERT promoter mutations in PTC. Transcriptomic data for 28 ETS factors were analyzed in the PTC cohort of The Cancer Genome Atlas (TCGA, n=399) and subsequently validated in a local cohort (n=93). In vitro experiments were performed to investigate the regulatory role in relation to BRAFV600E and TERT expression. TCGA identified ETS1, ERG, FLI1, GABPA, EHF, ETV6 and SPDEF as differentially expressed genes between stages I+II and III+IV. In both cohorts, EHF was consistently associated with adverse clinical features, BRAFV600E and TERT promoter mutation/expression. Notably, in BRAFV600E mutated PTC, high EHF expression was associated with shorter disease-free survival. Cases harboring concurrent BRAFV600E, TERT promoter mutations and high EHF expression exhibited the shortest disease-free survival. In cells harboring concurrent BRAFV600E and TERT promoter mutation, over-expression of EHF significantly increased TERT expression while knockdown or pharmacological inhibition of BRAF significantly decreased both EHF and TERT expression. In addition, ChIP-qPCR analysis suggested a potential binding of EHF in TERT promoter mutant cells but not in TERT promoter wild-type cells. The ETS transcription factor EHF is associated with poor prognosis in PTC. This is potentially mediated by BRAF-induced upregulation of EHF which in turn increases TERT expression in TERT promoter mutated cells.

Papillary thyroid carcinoma coexisting with benign thyroid and parathyroid pathology: clinical and pathomorphological features

Background. Papillary thyroid carcinoma (PTC) is the most frequent malignant neoplasm originating from follicular cells of thyroid gland. PTC is often coexisting with other benign thyroid pathology such as chronic lymphocytic thyroiditis, follicular thyroid adenoma, toxic thyroid adenoma, Graves’ disease, non-toxic multinodular goiter. PTC can be diagnosed in patients undergoing surgical treatment for hyperparathyroidism. However, the clinical and pathomorphological features of PTC in the presence of other benign thyroid or parathyroid pathology, as well as possible differences in surgical tactics, remain relevant as evidenced by previously published reports. The purpose of the study is to assess the prevalence and determine the differences in the clinical and pathomorphological parameters of PTC in the presence of benign thyroid and parathyroid pathology. Materials and methods. There were identified 91 patients with PTC, who underwent surgical treatment at the clinical bases of the Department of Surgery of the NSC “Institute of Biology and Medicine” of Taras Shevchenko National University of Kyiv. Results. In the studied PTC cohort, 31 (35 %) patients were without coexisted benign thyroid pathology and 60 (35 %) patients had it (PTC/coexisted). A statistically significantly higher number of mitoses per 10 high power fields in the PTC group were identified in 3 (10 %) patients, as compared to the absence of this pathohistological parameter in the PTC/coexisted (p = 0.037). Further analysis of these 3 cases showed that 4 mitotic figures were found in one PTC, and one mitotic figure in the other two cases per 10 high power fields (400×). Conclusions. Papillary thyroid carcinoma in patients with other benign thyroid pathology is associated with lower biological aggressiveness than PTC without comorbidity as evidenced by a lower frequency of mitotic figures per 10 high power fields. The presence of concomitant benign thyroid pathology can be considered as a favorable prognostic factor for patients with PTC.

Implications of isthmic location as a risk factor in papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) located in the isthmus generally has been known to have more extrathyroidal extension (ETE), lymph node involvement, and multifocality. The purpose of this study was to determine the clinical significance of an isthmic location of PTC. The records of 160 patients who underwent a total thyroidectomy due to a single, dominant isthmic PTC were retrospectively reviewed. The characteristics of isthmic cancer were compared with those of unilateral-lobar cancer in a PTC cohort at Seoul St. Mary's hospital. After propensity score matching for age, sex, and tumor size, 160 isthmic PTCs and 800 unilateral-lobar PTCs were compared. The clinicopathologic characteristics were analyzed to evaluate the prognostic significance of an isthmic tumor location. The isthmic group was significantly older (49.6 vs. 46.8 years, P=0.007) and had a smaller mean tumor size (0.8±0.4 vs. 1.0±0.7 cm, P<0.001) than the unilateral-lobar group. After propensity score matching, tumor size categories, ETE, multifocality, nodal metastasis and proportion of patients with more than five metastatic lymph nodes were similar in both groups. However, N1b cases were more frequent in the unilateral-lobar group both before and after propensity score matching. In multivariate analysis, isthmic location was not correlated with gross ETE, multifocality, and higher-risk N1 disease. Younger age and more than five metastatic nodes increased the risk of PTC recurrence. However, isthmic tumor location was not significantly correlated with recurrence-free survival. Isthmic location is not an independent risk factor for aggressive clinicopathologic features and is not related to PTC recurrence.

Papillary Thyroid Carcinomas with Tall Cell Features: An Intermediate Entity Between Classic and Tall Cell Subtypes.

Background: While the diagnosis of papillary thyroid carcinomas (PTCs) with tall cell features (PTCtcf) is often made for carcinomas with histological features intermediate between classic and tall cell subtypes of PTC (tcPTC), its comparative signature to that of either tcPTC or classic PTC is less clear. The objective of this study was to perform an integrative clinicopathologic and genomic analysis elucidating the spectrum of tcPTC, PTCtcf, and classic PTC. Methods: We analyzed all consecutive patients with tcPTC and PTCtcf evaluated at a tertiary academic referral center between 2005 and 2020, as well as a comparative cohort of classic PTC, in a retrospective observational cohort analysis. Clinicopathologic data were compared among the three groups, including progression-free survival (PFS), recurrent/persistent disease, and a negative composite outcome of death, progression, or need for advanced therapy. To specifically understand differences between tcPTC and PTCtcf, targeted next-generation sequencing was performed in a subset of these cohorts. Results: A total of 292 patients were analyzed (81 tcPTC, 65 PTCtcf, 146 classic PTC). Thirteen percent of tcPTC versus 8% of PTCtcf versus 1% of classic PTC had the advanced American Joint Committee on Cancer stage (p = 0.002). Similarly, macroscopic extrathyroidal extension was observed in 38% of tcPTC, 14% of PTCtcf, and 12% of classic PTC (p < 0.001). The 5-year PFS was 76.5%, 81.5%, and 88.3% for tcPTC, PTCtcf, and classic PTC, respectively, while the rates of the negative composite outcome 40.2% for tcPTC, 20.7% for PTCtcf, and 11.2% for classic PTC (p < 0.001). In a multivariable Cox regression analysis, the negative composite outcome was independently associated with tcPTC (HR 4.3 [confidence interval 1.1-16.1], p = 0.03). tcPTC demonstrated substantially more hotspot TERT promoter mutations than PTCtcf (44% vs. 6%, p = 0.012). Conclusions: Our study demonstrates a continuum of disease-specific risk of PTC, pointing at PTCtcf as an intermediate entity between tcPTC and classic PTC. These data provide a more refined understanding of risk at time of presentation, while better elucidating the diversity of genomic drivers.

NTRK Fusion in a Cohort of BRAF p. V600E Wild-Type Papillary Thyroid Carcinomas

Owing to the availability of a potent tropomyosin receptor kinase (TRK) inhibitor, it is necessary to develop an effective strategy to identify an enriched population of NTRK fusions in papillary thyroid carcinoma (PTC) in routine diagnostic practice. The reported prevalence of NTRK fusion in a large cohort of PTC is ∼3%. We performed an analysis to refine the characteristic histologic features of PTCs harboring NTRK fusions and further validate the diagnostic utility of pan-TRK immunohistochemistry as a screening tool. In this study, 450 PTCs known to harbor no BRAF p. V600E mutations were screened by pan-TRK immunohistochemistry, and the cases with TRK expression were confirmed by RNA-based next-generation sequencing assay. Eleven NTRK fusion cases were detected (2.4%), and all PTCs were classical subtypes. NTRK1 and NTRK3 were involved in the fusion with 9 different partner genes. Most cases showed similar characteristic histologic findings. Nodular permeative border, multinodular growth with a predominantly follicular pattern, extensive lymphatic invasion, and prominent internodular and intratumoral fibrosis were the characteristic histologic features of NTRK-rearranged PTCs. The ill-defined margins in the ultrasonography findings, which could not be clearly distinguished from the adjacent nontumorous thyroid tissue, were nodular permeative margins in histologic findings. Therefore, preoperative ultrasonographic findings in nodule margins were consistent with the final histologic findings. NTRK1/3 fusion in PTCs showed an overall sensitivity of 100% (95% CI, 71.51%-100%) and specificity of 100% (95% CI, 71.51%-100%) in the 22 cases examined, as confirmed with next-generation sequencing. Our study provides an integrative report of the preoperative ultrasonographic, histologic, immunohistochemical, and molecular features of NTRK-rearranged PTCs. Based on these findings, we propose an algorithmic approach for the stepwise assessment of NTRK fusions in PTCs.

Abstract 5776: Predictors of radioactive iodine refractoriness in papillary thyroid carcinomas

Abstract Optimized surgery and radioactive iodine (131I, RAI) are the cornerstone of treatment for papillary thyroid carcinoma (PTC). Although standard treatment is curative for most, 5-20% of PTC patients develop RAI refractory disease – the main cause of thyroid cancer-related deaths. Early predictors indicating therapeutic response to RAI therapy in PTC are yet to be elucidated. We performed whole-exome sequencing (at a median depth of 198x) on 158 patient-matched primary PTCs and germline DNA. Clinical data was used to categorize RAI avidity in the PTC cohort. Whereby, 66 RAI refractory and 92 RAI avid tumors were identified. Clinical data and somatic variants were analyzed to compare the clinicopathological presentation, genomic landscape and mutational signatures between RAI refractory and avid PTCs. RAI refractory tumors were significantly associated with distinct aggressive clinicopathological features, including positive surgical margins (65.5% versus 26.7%; p=0.016) and the presence of lymph node metastases at primary diagnosis (62.5% versus 30.1%; p=0.012); higher nonsilent tumor mutation burden (p=0.011); and the enrichment of APOBEC-related single base substitution (SBS) COSMIC mutational signatures 2 (p=0.03) and 13 (p&amp;lt;0.001). APOBEC mutational signatures were not associated with BRAFV600E mutation. Notably, using multivariate logistic regression analysis only the SBS13 (odds ratio 13.01, 95% confidence intervals 1.20-140.94) APOBEC mutational signature was revealed to be an independent predictor of RAI refractoriness in PTC (p=0.035). Furthermore, using Cox proportional hazards SBS13-positive tumors (hazard ratio 3.52, 95% confidence intervals 1.79-6.91) were also significantly associated with poorer progression-free survival (p&amp;lt;0.001), albeit only in univariate analysis. This study highlights distinct clinical and genomic features in RAI refractory PTC, but above all proposes the APOBEC SBS13 mutational signature as an independent predictor of RAI refractoriness in a more aggressive subgroup of PTC. Where detection of RAI refractory disease following standard surgical PTC removal, and more suitable therapeutic interventions may potentially improve patient outcomes. Citation Format: Tariq Masoodi, Sarah Siraj, Abdul K. Siraj, Saud Azam, Zeeshan Qadri, Sandeep K. Parvathareddy, Khawla S. Al-Kuraya. Predictors of radioactive iodine refractoriness in papillary thyroid carcinomas [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 5776.

Construction of a Tumor Immune Microenvironment-Related Prognostic Model in BRAF-Mutated Papillary Thyroid Cancer.

BRAF mutation is a representative oncogenic mutation, with a frequency of 60% in papillary thyroid carcinoma (PTC), but the reasons for the poor prognosis and more aggressive course of BRAF-mutated PTC are controversial. Tumor immune microenvironment (TIME) is an essential factor permitting the development and progression of malignancy, but whether TIME participates in the prognosis of BRAF-mutated PTC has not yet been reported. The primary goal of the present study was to provide a comprehensive TIME-related prognostic model to increase the predictive accuracy of progression-free survival (PFS) in patients with BRAF-mutated PTC. In this study, we analyzed the mRNA-seq data and corresponding clinical data of PTC patients obtained from the TCGA database. By calculating the TIME scores (immune score, stromal score and ESTIMATE score), the BRAF mutation group (n=237) was dichotomized into the high- and low-score groups. By functional analysis of differentially expressed genes (DEGs) in different high/low score groups, we identified 2 key TIME-related genes, HTR3A and NIPAL4, which affected PFS in BRAF-mutated PTC. A risk scoring system was developed by multivariate Cox analysis based on the abovementioned 2 TIME-related genes. Then, the BRAF-mutated cohort was divided into the high- and low-risk groups using the median risk score as a cutoff. A high risk score correlated positively with a higher HTR3A/NIPAL4 expression level but negatively with PFS in BRAF-mutated PTC. Ultimately, a nomogram was constructed by combining risk score with clinical parameter (Tumor stage), and the areas under the ROC curve (AUCs) of the nomogram for predicting 1-, 3- and 5-year PFS were then calculated and found to be 0.694, 0.707 and 0.738, respectively, indicating the improved accuracy and clinical utility of the nomogram versus the risk score model in the BRAF-mutated PTC cohort. Moreover, we determined the associations between prognostic genes or risk score and immune cell infiltration by two-way ANOVA. In the high-risk score, high HTR3A expression, and high NIPAL4 expression groups, higher infiltration of immune cells was found. Collectively, these findings confirm that the nomogram is effective in predicting the outcome of BRAF-mutated PTC and will add a spatial dimension to the developing risk stratification system.

The systemic immune-inflammation index-based model is an effective biomarker on predicting central lymph node metastasis in clinically nodal-negative papillary thyroid carcinoma.

A high proportion of papillary thyroid carcinoma (PTC) patients are involved in central lymph node metastasis (CLNM) with preoperative imaging examinations showing clinically nodal-negative (cN0). Meanwhile, many inflammatory biomarkers are also proven as effective factors to predict the outcomes of cancer patients and tumor progression. Thus, the values of these factors are investigated to help detecting CLNM in cN0 PTC patients. 406 cN0 PTC patients who underwent curative surgery were retrospectively analyzed. CLNM was determined by histopathological examination following the thyroidectomy. Multiple inflammatory biomarkers were comprehensively researched. A total of 406 consecutive patients were eventually included. The univariate and multivariate analyses revealed that age (OR: 0.924, 95% CI: 0.909, 0.940), gender (OR: 1.781, 95% CI: 1.060, 2.993), location of tumors (OR: 2.229, 95% CI: 1.228, 4.046) and level of systemic immune-inflammation index (SII) (OR: 1.005, 95% CI: 1.004, 1.006) were independently associated with CLNM in cN0 PTC patients, and the SII-based predictive model was constructed using these four factors. Receiver operating characteristic (ROC) curves showed significant results of the SII-based predictive model in PTC cohort with area under curve (AUC) as 0.814 (95% CI: 0.771-0.857) and in PTMC subgroup with AUC as 0.803 (95% CI: 0.752-0.854). The SII-based model can effectively help predicting CLNM in both cN0 PTC patients and cN0 PTMC patients.

Highly accurate diagnosis of papillary thyroid carcinomas based on personalized pathways coupled with machine learning.

Thyroid nodules are neoplasms commonly found among adults, with papillary thyroid carcinoma (PTC) being the most prevalent malignancy. However, current diagnostic methods often subject patients to unnecessary surgical burden. In this study, we developed and validated an automated, highly accurate multi-study-derived diagnostic model for PTCs using personalized biological pathways coupled with a sophisticated machine learning algorithm. Surprisingly, the algorithm achieved near-perfect performance in discriminating PTCs from non-tumoral thyroid samples with an overall cross-study-validated area under the receiver operating characteristic curve (AUROC) of 0.999 (95% confidence interval [CI]: 0.995-1) and a Brier score of 0.013 on three independent development cohorts. In addition, the algorithm showed excellent generalizability and transferability on two large-scale external blind PTC cohorts consisting of The Cancer Genome Atlas (TCGA), which is the largest genomic PTC cohort studied to date, and the post-Chernobyl cohort, which includes PTCs reported after exposure to radiation from the Chernobyl accident. When applied to the TCGA cohort, the model yielded an AUROC of 0.969 (95% CI: 0.950-0.987) and a Brier score of 0.109. On the post-Chernobyl cohort, it yielded an AUROC of 0.962 (95% CI: 0.918-1) and a Brier score of 0.073. This algorithm also is robust against other various types of clinical scenarios, discriminating malignant from benign lesions as well as clinically aggressive thyroid cancer with poor prognosis from indolent ones. Furthermore, we discovered novel pathway alterations and prognostic signatures for PTC, which can provide directions for follow-up studies.

Antibody Supervised Training of a Deep Learning Based Algorithm for Leukocyte Segmentation in Papillary Thyroid Carcinoma.

The quantity of leukocytes in papillary thyroid carcinoma (PTC) potentially have prognostic and treatment predictive value. Here, we propose a novel method for training a convolutional neural network (CNN) algorithm for segmenting leukocytes in PTCs. Tissue samples from two retrospective PTC cohort were obtained and representative tissue slides from twelve patients were stained with hematoxylin and eosin (HE) and digitized. Then, the HE slides were destained and restained immunohistochemically (IHC) with antibodies to the pan-leukocyte anti CD45 antigen and scanned again. The two stain-pairs of all representative tissue slides were registered, and image tiles of regions of interests were exported. The image tiles were processed and the 3,3'-diaminobenzidine (DAB) stained areas representing anti CD45 expression were turned into binary masks. These binary masks were applied as annotations on the HE image tiles and used in the training of a CNN algorithm. Ten whole slide images (WSIs) were used for training using a five-fold cross-validation and the remaining two slides were used as an independent test set for the trained model. For visual evaluation, the algorithm was run on all twelve WSIs, and in total 238,144 tiles sized 500 × 500 pixels were analyzed. The trained CNN algorithm had an intersection over union of 0.82 for detection of leukocytes in the HE image tiles when comparing the prediction masks to the ground truth anti CD45 mask. We conclude that this method for generating antibody supervised annotations using the destain-restain IHC guided annotations resulted in high accuracy segmentations of leukocytes in HE tissue images.

M6A RNA methylation regulators have prognostic value in papillary thyroid carcinoma.

N6-Methyladenosine (m6A) is a ubiquitous RNA modification with vital roles in various cancers, but little is known about its role in papillary thyroid carcinoma (PTC), a common endocrine malignancy. In this study, an m6A RNA methylation regulator-based biomarker signature was developed for the effective prediction of prognosis in patients with PTC. The gene expression profiles of m6A RNA methylation regulators and the corresponding clinical information was downloaded from The Cancer Genome Atlas (TCGA). Differentially expressed m6A RNA methylation regulators between tumor and normal control samples, and correlation expression levels, clinical parameters, and outcomes were evaluated. And a prognostic signature was built using a PTC cohort from TCGA. The expression level of HNRNPC was remarkably upregulated in tumor samples, while WTAP, RBM15, YTHDC2, YTHDC1, FTO, METTL14, METTL3, ALKBH5, KIAA1429, YTHDF1, and ZC3H13 were significantly downregulated in the cancer specimens compared with those in control samples. A three-gene prognostic signature comprising RBM15, KIAA1429, and FTO could predict overall survival in patients with PTC. In addition, the prognostic signature-based risk score was identified as an independent prognostic indicator for PTC. We established a robust m6A RNA methylation regulator-based molecular signature for predicting prognosis in patients with PTC with high accuracy; this signature might provide important guidance for therapeutic strategies.

BRAFV600E Mutation is Associated with an Increased Risk of Papillary Thyroid Cancer Recurrence.

Papillary thyroid carcinoma is the most common endocrine malignancy and one of the most common cancers worldwide. However, the optimal timing and frequency of surveillance to assess for recurrence remain undetermined. As the incidence of thyroid cancer continues to rise worldwide, identifying risk factors for recurrence and investigating intervals and durations of surveillance are paramount to adapt treatment and follow-up plans to high-risk individuals and to reduce interventions for low-risk patients. Our dataset included an unselected cohort of papillary thyroid carcinoma (PTC) patients who underwent a total thyroidectomy (or unilateral then completion thyroidectomy) at a single institution from 2000 to 2007. BRAF genotyping was performed on available specimens by a validated PCR-based assay. Pathologic structural recurrence was the primary outcome. We performed univariate and multivariable analyses to identify predictors of cancer recurrence. In total, 599 patients underwent complete resection of the thyroid gland for PTC. The cohort was young (mean age 45.0years), predominately female (n = 462, 76.9%), and median follow-up was 10.3years (IQR 5.4-12.2). Recurrence occurred more commonly in the BRAFV600E group (18.6 vs. 9.9%, p = 0.02). BRAF independently predicted PTC recurrence (HR 2.81, p = 0.006). BRAF mutation is an independent predictor of papillary thyroid carcinoma long-term recurrence. Understanding molecular characteristics of individual thyroid cancers may help risk-stratify patients and direct them toward more appropriate initial care and long-term surveillance strategies.

Downregulation of SMOC2 expression in papillary thyroid carcinoma and its prognostic significance

Secreted Protein Acidic and Rich in Cysteine (SPARC)-related modular calcium-binding protein-2 (SMOC2), a secreted matricellular protein, is reported to be involved in various processes related to cancer progression such as regulating the cell cycle, angiogenesis, and invasion. However, its expression and prognostic significance in papillary thyroid carcinomas (PTCs) remains unknown. Using immunohistochemistry, we evaluated the expression profile of SMOC2 and its prognostic value in a large cohort of PTCs. Real time-PCR analysis with fresh-frozen tissues showed that SMOC2 mRNA expression in PTCs was substantially lower than the expression in matched non-cancerous thyroid tissues, consistent with the results from thyroid cancer cell lines. Immunohistochemical analysis demonstrated that SMOC2 was normally present in thyroid follicular epithelial cells and the expression level was maintained in nodular hyperplasia. However, SMOC2 expression was significantly lower in lymphocytic thyroiditis and follicular tumors including follicular adenomas and carcinomas. In particular, 38% of PTCs exhibited a complete loss of SMOC2 expression, which was associated with the presence of BRAF (V600E) mutation. Moreover, SMOC2 further declined during lymph node metastasis in PTCs. DNA methylation chip analysis revealed one hypermethylated CpG site in the promoter region of SMOC2 gene, suggesting an epigenetic regulation of SMOC2 in PTCs. Remarkably SMOC2 positivity was associated with improved recurrence-free survival along with female sex, tumor size, and the N stage. However, SMOC2 was not identified as an independent prognostic marker in multivariate analyses. Taken together, SMOC2 expression is significantly down-regulated in PTCs and SMOC2 positivity is closely associated with better clinical outcomes, suggesting that SMOC2 can be a prognostic marker in PTC patients.

Factors associated with recurrence and death in patients with aggressive hobnail morphology papillary thyroid carcinoma.

e17590 Background: Papillary thyroid carcinoma (PTC) with hobnail morphology (HM) is an aggressive variant associated with poorer outcomes compared to classical PTC, with a little over 100 cases reported in the literature. We aim to identify prognostic factors potentially associated with recurrence and death in the largest single institutional experience of PTC with HM. Methods: From an IRB approved registry, we identified all PTC HM cases with patient, diagnostic and treatment data and outcomes. Hobnail variant (HV) PTC had ≥30% HM; pure hobnail features (PHF) had &lt; 30% HM without tall cell morphology (TCM) &amp; multi variant features (MVF) had both HM &amp; TCM. Demographic and clinical features at time of HM diagnosis that were potentially associated with 3-yr event free (death or recurrence) survival (EFS) were evaluated using Kaplan-Meir method (KM). Results: Forty-five (median age 55 yo, range 19-86 yo; 66.7% female) HM pts (35 HM at initial PTC, 10 at recurrence) were evaluable. Majority were ECOG 0 (84.1%). HM: 44.4% MVF, 37.8% PHF, &amp; 17.8% HV; 68.9% pT3/T4; 64.4% node positive; &amp; 15.6% metastatic. Positive surgical margins (+SM) with HM in 31.8%. RAI at HM given to 73%. Overall EFS was 83.5% at 1-yr &amp; 69.6% at 2-yr. Of 13 events at 3 yrs, 4 were deaths (3 from PTC) &amp; 9 recurrences. All events were in those &gt; 55 yo (p &lt; 0.001) with pT3/T4 disease (p = 0.01). Non-0 ECOG (KM 2-yr EFS: 28.6% vs 77.7%, p = 0.002), cT3/T4 (49.5% vs 85.5%p = 0.004), and +SM (32.1% vs 92.1%, p = 0.001) were also associated with EFS compared to their counterpart. HM grouping, RAI, initial HM vs HM at recurrence, sex, and tumor size were not statistically significant. Conclusions: To our knowledge, this is the largest reported cohort of PTC with HM. We identified several factors potentially associated with recurrence and death. There was no difference in outcomes between HV versus PHF versus MVF, which raises question to validity of 30% cutoff in defining “variant” versus “features of variant”. Age &gt; 55 yo, T3/T4 disease, and +SM exhibited significantly inferior EFS. Further evaluation in a multi-institutional cohort will help in validating these findings and help identify patients who warrant more aggressive initial treatment.

Telomerase reverse transcriptase mutations are independent predictor of disease-free survival in Middle Eastern papillary thyroid cancer.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Tumor recurrence occurs in ∼20% of PTCs and some reach advanced stages. Promoter mutation in the telomerase reverse transcriptase (TERT) gene is identified to be a prognostic marker in PTC. However, the contribution of TERT promoter mutation to cancer progression in PTC patients is still not fully understood. In this study, we investigated the incidence of TERT promoter mutations and TERT protein expression and their association with clinicopathological outcomes in a large cohort of PTC samples using direct sequencing technology and immunohistochemistry. Furthermore, two PTC cell lines were utilized to investigate role of TERT mutations in mediating metastasis. Two promoter hotspot mutations C228T and C250T were identified in 18.0% (167/927) of our cohort and were significantly associated with poor 5 years disease-free survival and distant metastasis of PTC. TERT protein overexpression was noted in 20.1% of our PTC cohort and was significantly associated with poor prognostic markers such as older age, extrathyroidal extension and Stage IV tumors. A significant association was also found between TERT overexpression and epithelial-mesenchymal transition (EMT) markers. Functional analysis showed that TERT inhibition reduced cell growth, invasion, migration and angiogenesis in PTC via suppression of EMT in PTC cells. Our results suggest that TERT promoter mutation is an independent predictor of disease-free survival and might drive the metastasis, and downregulation of TERT could potentiate antitumor and antimetastatic activities in PTC.

Heterogeneous Prognoses for pT3 Papillary Thyroid Carcinomas and Impact of Delayed Risk Stratification.

Papillary thyroid carcinomas (PTC) in the pT3 category constitute a heterogeneous group of tumors with a variable risk of recurrence. The objectives of this study were (i) to estimate disease-free survival (DFS) and identify prognostic factors associated with recurrence in a cohort of pT3 PTC, and (ii) to evaluate the concept of delayed risk stratification in a cohort of pT3 tumors. A total of 560 patients with pT3 PTC, treated and followed at the authors' institution, were studied. They were divided into three groups: group 1, pT3 ≤10 mm; group 2, pT3 >10 mm with extrathyroidal invasion (ETI); and group 3, pT3 due to a tumor size >4 cm. DFS was estimated using the Kaplan-Meier method, and associated prognostic features were studied in univariate and multivariate Cox model-based analyses in each group. Then, DFS was studied for each group according to the six- to eight-month status (remission or not). DFS at 10 years was 75% for the entire cohort and was 89%, 67%, and 82% in groups 1, 2, and 3, respectively (p < 0.0001). Multivariate analysis identified three factors significantly associated with reduced DFS: lymph node (LN) involvement, male sex, and group 2 (>1 cm with ETI). A trend toward a worse prognosis in patients with pT3 N0/Nx PTC >10 mm with ETI was found in comparison with the other pT3 N0/Nx patients. When the six- to eight-month checkup was normal, the DFS at 10 years increased to 98%, 96%, and 91% in groups 1-3, respectively. Furthermore, in this case, initial LN involvement no longer seemed to affect the prognosis in those groups. PTC ≤10 mm with ETI and large tumors >4 cm without ETI both have a low-recurrence risk when there are no adverse associated prognostic features such as LN involvement. LN involvement, especially in the lateral compartment (N1b), is a strong prognostic factor of recurrence in pT3 PTC. Delayed risk stratification can be applied in pT3 PTC patients. Those cured at the first checkup, including those with limited LN involvement, have excellent outcomes, which should prompt clinicians to adapt subsequent management accordingly.

Genome-Wide Expression Screening Discloses Long Noncoding RNAs Involved in Thyroid Carcinogenesis.

Long noncoding RNAs (lncRNAs) regulate pathological processes, yet their potential roles in papillary thyroid carcinoma (PTC) are poorly understood. To profile transcriptionally dysregulated lncRNAs in PTC and identify lncRNAs associated with clinicopathological characteristics. We performed RNA sequencing of 12 paired PTC tumors and matched noncancerous tissues and correlated the expression of lncRNAs with clinical parameters. The 2 most significantly dysregulated lncRNAs were studied in an Ohio PTC cohort (n = 109) and in PTC data (n = 497) from The Cancer Genome Atlas. A combination of laboratory-based studies and computational analysis using clinical data and samples and a publically available database. Correlation between expression values and clinical parameters. We identified 218 lncRNAs showing differential expression in PTC (fold change ≥ 2.0, P < .01). Significant correlation was observed between the expression of 2 lncRNAs (XLOC_051122 and XLOC_006074) and 1) lymph node metastasis (N stage) and 2) BRAF(V600E) mutation. Among patients with wild-type BRAF, the expression of these 2 lncRNAs showed significantly higher levels in the patients with lymph node metastasis. In silico analysis of these lncRNAs pinpointed cell movement and cellular growth and proliferation as targeted functions. Comprehensive expression screening identified 2 novel lncRNAs associated with risk factors of adverse prognosis in PTC patients. These lncRNAs may be novel players in PTC carcinogenesis.

Abstract 3117: Pleiotrophin is a marker of poor prognosis in Middle Eastern papillary thyroid carcinoma

Abstract Pleiotrophin (PTN) is a heparin binding growth factor known to have role in neuronal development. It is highly expressed in embryo but has a very limited expression in adult tissues. PTN is considered a proto-oncogene and has been hypothesized to play role in oncogenesis as its expression is found to be increased in many different cancer subtypes. Its role in cell transformation, cell growth, survival, migration and angiogenesis has also been shown in various different types of cancers. The function of PTN is hypothesized to be carried out by its interaction with cell surface proteoglycans or binding to its selective cell surface receptor, protein tyrosine phosphatase receptor Z1 (PTPRZ1). The significance of role of PTN in pathogenesis of thyroid cancer has not been explored especially with the fact that papillary thyroid carcinoma (PTC) originating in this ethnic population is the second most common female malignancy, after breast. So in search for novel druggable molecular target we sought for PTN expression in a large cohort of Saudi PTC. We analysed PTN alteration in more than 1000 primary papillary thyroid carcinoma in a tissue microarray format with clinical follow up data. We found that PTN was overexpressed in 65.5% (658/1006) of PTC and was significantly associated with aggressive clinical parameters such as tall cell variant histological subtype (p = 0.0333), extrathyroidal extension (p = 0.0292), lymphovascular invasion (p = 0.0182) and large tumour size (p = 0.0160). Important significant molecular association was seen with PTPRZ-1 (p = 0.0316), Midkine (p = 0.0008) and pSTAT-3 (p&amp;lt;0.0001). Finally patients showing PTN overexpression have worse disease free survival compared to patients showing low or absent PTN expression (p = 0.0218). On multivariate analysis PTN is found to be an independent marker of poor prognosis taking into consideration parameters such as Age, Stage, Lymph node status and Extrathyroidal extension (p = 0.0430). This study highlights the importance of PTN as druggable molecular target which can be therapeutically exploited by its inhibitors in treatment of PTC. Keywords: Papillary Thyroid Cancer; Pleiotrophin; Pleiotrophin Receptor Citation Format: Shaham Beg, Maqbool Ahmed, Azhar Hussein, Rong Bu, Zeeshan Qadri, Saif AlSobhi, Fouad Al Dayel, Abdul K. Siraj, Khawla S. Al-Kuraya. Pleiotrophin is a marker of poor prognosis in Middle Eastern papillary thyroid carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3117.

Cadherin-6 promotes EMT and cancer metastasis by restraining autophagy.

The transdifferentiation of epithelial cells toward a mesenchymal condition (EMT) is a complex process that allows tumor cells to migrate to ectopic sites. Cadherins are not just structural proteins, but they act as sensors of the surrounding microenvironment and as signaling centers for cellular pathways. However, the molecular mechanisms underlying these signaling functions remain poorly characterized. Cadherin-6 (CDH6) is a type 2 cadherin, which drives EMT during embryonic development and it is aberrantly re-activated in cancer. We recently showed that CDH6 is a TGFβ target and an EMT marker in thyroid cancer, suggesting a role for this protein in the progression of this type of tumor. Papillary thyroid carcinomas (PTCs) are usually indolent lesions. However, metastatic spreading occurs in about 5% of the cases. The identification of molecular markers that could early predict the metastatic potential of these lesions would be strategic to design more tailored approaches and reduce patients overtreatment. In this work, we assessed the role of CDH6 in the metastatic progression of thyroid cancer. We showed that loss of CDH6 expression profoundly changes cellular architecture, alters the inter-cellular interaction modalities and attenuates EMT features in thyroid cancer cells. Using a yeast two-hybrid screening approach, based on a thyroid cancer patients library, we showed that CDH6 directly interacts with GABARAP, BNIP3 and BNIP3L, and that through these interactions CDH6 restrains autophagy and promotes re-organization of mitochondrial network through a DRP1-mediated mechanism. Analysis of the LIR domains suggests that the interaction with the autophagic machinery may be a common feature of many cadherin family members. Finally, the analysis of CDH6 expression in a unique cohort of human PTCs showed that CDH6 expression marks specifically EMT cells. and it is strongly associated with metastatic behavior and worse outcome of PTCs.

Integrated genomics of thyroid cancer

Objective Advances in DNA sequencing technology have permitted comprehensive genomic characterization of the most common types of cancer, including those of the thyroid gland. The Cancer Genome Atlas (TCGA) program of the U.S. National Institutes of Health (a joint NCI and NHGRI effort) has performed the first of several attempts to define the genomic landscape of thyroid cancer by identifying the somatic genetic changes of a large cohort of papillary thyroid carcinoma (PTC). Methods The TCGA Research Network performed an integrated genomic analysis of nearly 500 PTCs, the most common type, using next generation DNA sequencing and other pan-genomic methods, together with detailed clinical and pathologic data. Results Despite significant pre-existing knowledge about the genetics of PTC, the TCGA project illuminated many novel aspects of the genetics of PTC. Novel driving alterations, both novel single nucleotide variants and gene fusions, were identified. Driving events were nearly mutually exclusive. Tumors were divided into BRAF-V600E-like and RAS-like groups based on their gene expression profiles and were shown to have distinct differentiation and signaling properties. Several differentially expressed miRs were identified and hypothesized to play a prognostic role in PTC. Discussion The overarching conclusion of this study is PTC is much more genetically diverse than previously recognized, with BRAF-driven tumors being genetically diverse and also fundamentally different from RAS-driven tumors.