Clinical and Molecular Characteristics May Alter Treatment Strategies of Thyroid Malignancies in DICER1 Syndrome

C LI NI CA L RE SE AR CH A RT IC LE Clinical and Molecular Characteristics May Alter Treatment Strategies of Thyroid Malignancies in DICER1 Syndrome Karin van der Tuin,1* Leanne de Kock,2* Eveline J. Kamping,3 Sabine E. Hannema,4 Marie-Jose M. Pouwels,5 Marek Niedziela,6 Tom van Wezel,7 Frederik J. Hes,1 Marjolijn C. Jongmans,3,8,9 William D. Foulkes,2* and Hans Morreau7* Department of Clinical Genetics, Leiden University Medical Centre, 2300 RC Leiden, Netherlands; Department of Human Genetics, McGill University, Montreal, Quebec H3A 0C7, Canada; 3Department of Clinical Genetics, Radboud University Medical Centre, 6525 GA Nijmegen, Netherlands; 4Department of Pediatrics, Leiden University Medical Centre, 2300 RC Leiden, Netherlands; 5Department of Internal Medicine, Division of Endocrinology, Medical Spectrum Twente, 7500 KA Enschede, Netherlands; 6 Department of Pediatric Endocrinology and Rheumatology, Karol Jonscher’s Clinical Hospital, Poznan University of Medical Sciences, 61-701 Poznan, Poland; 7Department of Pathology, Leiden University Medical Centre, 2300 RC Leiden, Netherlands; 8Department of Medical Genetics, Utrecht University Medical Center, 3584 CX Utrecht, Netherlands; and 9Princess Maxima Center for Pediatric Oncology, 3584 EA Utrecht, Netherlands 2 ORCiD numbers: 0000-0002-5379-5084 (K. van der Tuin); 0000-0001-7314-1371 (L. de Kock); 0000-0001-7427-4651 (W. D. Foulkes). Context: DICER1 syndrome is a rare autosomal-dominantly inherited disorder that predisposes to a variety of cancerous and noncancerous tumors of mostly pediatric and adolescent onset, including differentiated thyroid carcinoma (DTC). DTC has been hypothesized to arise secondarily to the increased prevalence of thyroid hyperplastic nodules in syndromic patients. Objective: To determine somatic alterations in DICER1-associated DTC and to study patient outcomes. Design: Retrospective series. Setting: Tertiary referral centers. Patients: Ten patients with germline pathogenic DICER1 variants and early-onset DTC. Methods: Somatic DICER1 mutation analysis, extensive somatic DNA variant and gene fusion analyses were performed on all tumors. Results: Median age at DTC diagnosis was 13.5 years and there was no recurrent or metastatic disease (median follow-up, 8 years). All thyroid specimens showed diffuse nodular hyperplasia with at least one focus suspicious of DTC but without infiltrative growth, extrathyroidal extension, vascular invasion, or lymph node metastasis. Most of the individual nodules (benign and malignant) sampled from the 10 tumors harbored distinct DICER1 RNase IIIb hotspot mutations, indicating a polyclonal composition of each tumor. Furthermore, nine of 10 DICER1-related DTCs lacked wellknown oncogenic driver DNA variants and gene rearrangements. Conclusion: On the basis of our clinical, histological, and molecular data, we consider that most DICER1-related DTCs form a low-risk subgroup. These tumors may arise within one of multiple ISSN Print 0021-972X ISSN Online 1945-7197 Printed in USA Copyright © 2019 Endocrine Society Received 10 April 2018. Accepted 21 September 2018. First Published Online 26 September 2018 doi: 10.1210/jc.2018-00774 *K.v.d.T., L.d.K., W.D.F., and H.M. contributed equally to this study. Abbreviations: DTC, differentiated thyroid cancer; FVPTC, follicular variant of papillary thyroid carcinoma; MNG, multinodular goiter; PPB, pleuropulmonary blastoma; RAI, radioactive iodine. J Clin Endocrinol Metab, February 2019, 104(2):277–284 https://academic.oup.com/jcem 277 1 278 van der Tuin et al DICER1-Related Thyroid Neoplasia J Clin Endocrinol Metab, February 2019, 104(2):277–284 benign monoclonal nodules; thus, hemi-thyroidectomy or, more likely, total thyroidectomy may often be required. However, radioiodine treatment may be unnecessary given the patients’ ages and the tumors’ low propensity for metastases. (J Clin Endocrinol Metab 104: 277–284, 2019) D Patients and Methods Study population and design We studied 10 patients from eight families with germline pathogenic DICER1 variants who had young-onset nodular thyroid hyperplasia containing at least one reported focus of DTC, diagnosed between 2004 and 2017. Clinical information, pathology reports, and details of medical history were collected from the treating physicians with full patient and/or parental consent. The study was approved by the local ethical committee of the Leiden University Medical Centre (approval no. P14.312). Histological analysis The tumors were reviewed by pathologists at the referring institutions and by our central reference pathologist (H.M.). Molecular analysis Total nucleic acid (i.e., undivided DNA and RNA) was isolated from formalin-fixed paraffin-embedded tissue cores (0.6-mm diameter and variable length) or microdissected tissue regions using a fully automated extraction procedure (14). Broad DNA variant and gene fusion analyses were performed using the following methods. Somatic DICER1 variant analysis of the RNase IIIa and RNase IIIb domains was performed by conventional Sanger sequencing at either Radboud University Medical Centre or McGill University and Genome Quebec Innovation Centre (primers available on request). Somatic DNA variant analysis was performed using a customized nextgeneration sequencing AmpliSeq Cancer Hotspot Panel (Thermo Fisher Scientific, Waltham, MA) targeting 50 genes (including BRAF, NRAS, HRAS, KRAS, TP53, PTEN, and PIK3CA), as previously described (15). TERT promotor variant (NM_ 198253.2; c.-57A.C, c.-124C.T and c.-146 C.T) analysis was performed by Sanger sequencing. Gene fusion analysis was performed using the FusionPlex comprehensive thyroid and lung kit, version 2, for Ion Torrent (ArcherDX, Boulder, CO), which captures relevant exons from 34 genes (including RET, NTRK1-3, and ALK) according to the manufacturer’s protocol. Data analysis was performed using the online Archer Analysis software, version 5.0 (analysis. archerdx.com). Only “strong-evidence” fusions called by the software were reported. This relatively new method was first validated on 56 formalin-fixed paraffin-embedded DTC samples (data not shown). Results Clinical characteristics In total, 10 patients (from eight different families) with DICER1-related thyroid carcinomas were included in this study. Details on six of these cases have been previously published (Table 1) (6, 16–19). The mean age (6SD) at DTC diagnosis was 14.7 6 6.2 years (range, 7 ICER1 syndrome is a rare autosomal-dominantly inherited disorder that predisposes to a variety of cancerous and noncancerous tumors of mostly pediatric and adolescent onset (1). The DICER1 gene encodes a ribonuclease III enzyme involved in cleaving noncoding small RNA precursors to generate mature miRNAs, which in turn, posttranscriptionally regulate expression of many genes (2). Pleuropulmonary blastoma (PPB; a rare pediatric lung tumor), cystic nephroma, and ovarian Sertoli-Leydig cell tumor are the hall (...truncated)