Familial Nonmedullary Thyroid Cancer Research Articles

Epidemiological, clinicopathological, and evolutionary profile of familial non-medullary thyroid carcinoma (FNMTC) in 3 families

Epidemiological, clinicopathological, and evolutionary profile of familial non-medullary thyroid carcinoma (FNMTC) in 3 families

Identification of P21 (CDKN1A) Activated Kinase 4 as a Susceptibility Gene for Familial Non-Medullary Thyroid Carcinoma.

Background: Familial non-medullary thyroid carcinoma (FNMTC) is a genetically predisposed disease with unclear genetic mechanisms. This makes research on susceptibility genes important for the diagnosis and treatment options. Methods: This study included a five-member family affected by papillary thyroid carcinoma. The candidate genes were identified through whole-exome sequencing and Sanger sequencing in family members, other FNMTC patients, and sporadic non-medullary thyroid carcinoma patients. The pathogenicity of the mutation was predicted using in silico tools. Cell phenotype experiments in vitro and models of lung distant metastasis in vivo were conducted to confirm the characteristics of the mutation. Transcriptome sequencing and mechanistic validation were employed to compare the disparities between PAK4 wild-type (WT) and PAK4 mutant (MUT) cell lines. Results: This mutation alters the protein structure, potentially increasing instability by affecting hydrophobicity, intra-molecular hydrogen bonding, and phosphorylation sites. It specifically promotes phosphorylated PAK4 nuclear translocation and expression in thyroid tissue and cell lines. Compared with the WT cells line, PAK4 I417T demonstrates enhanced proliferation, invasiveness, accelerated cell division, and inhibition of cell apoptosis in vitro. In addition, it exhibits a significant propensity for metastasis in vivo. It activates tumor necrosis factor signaling through increased phosphorylation of PAK4, JNK, NFκB, and c-Jun, unlike the WT that activates it via the PAK4-NFκ-MMP9 axis. In addition, PAK4 MUT protein interacts with matrix metalloproteinase (MMP)3 and regulates MMP3 promoter activity, which is not observed in the WT. Conclusions: Our study identified PAK4: c.T1250C: p.I417T as a potential susceptibility gene for FNMTC. The study concludes that the mutant form of PAK4 exhibits oncogenic function, suggesting its potential as a novel diagnostic molecular marker for FNMTC.

Chromosomal localization of mutated genes in non-syndromic familial thyroid cancer.

Familial non-medullary thyroid carcinoma (FNMTC) is a type of thyroid cancer characterized by genetic susceptibility, representing approximately 5% of all non-medullary thyroid carcinomas. While some cases of FNMTC are associated with familial multi-organ tumor predisposition syndromes, the majority occur independently. The genetic mechanisms underlying non-syndromic FNMTC remain unclear. Initial studies utilized SNP linkage analysis to identify susceptibility loci, including the 1q21 locus, 2q21 locus, and 4q32 locus, among others. Subsequent research employed more advanced techniques such as Genome-wide Association Study and Whole Exome Sequencing, leading to the discovery of genes such as IMMP2L, GALNTL4, WDR11-AS1, DUOX2, NOP53, MAP2K5, and others. But FNMTC exhibits strong genetic heterogeneity, with each family having its own pathogenic genes. This is the first article to provide a chromosomal landscape map of susceptibility genes associated with non-syndromic FNMTC and analyze their potential associations. It also presents a detailed summary of variant loci, characteristics, research methodologies, and validation results from different countries.

CHEK2 germline variants identified in familial nonmedullary thyroid cancer lead to impaired protein structure and function

Approximately 5-15% of non-medullary thyroid cancers (NMTC) present in a familial form (FNMTC). Unlike sporadic NMTC, the genetic basis of FNMTC remains largely unknown, representing a limitation for diagnostic, therapeutic and follow-up decisions. Recently, germline mutations in DNA repair-related genes have been described in cases with thyroid cancer, suggesting a role in FNMTC etiology. Here, two FNMTC families were studied, each with two members affected with thyroid cancer. Ninety-four hereditary cancer predisposition genes were analysed through next-generation sequencing, revealing two germline missense variants in CHEK2 (c.962A>C, p.E321A and c.470T>C, p.I157T), which segregated with thyroid cancer in each FNMTC family. p.E321A, located in the CHK2 protein kinase domain, is a rare variant, previously unreported in the literature. Conversely, p.I157T, located in CHK2 forkhead-associated domain, has been extensively described, having conflicting interpretations of pathogenicity. CHK2 proteins (wild type and variants) were characterized using biophysical methods, molecular dynamics simulations, and immunohistochemistry. Overall, biophysical characterization of these CHK2 variants showed that they have compromised structural and conformational stability and impaired kinase activity, compared to the wild-type protein. Additionally, CHK2 appears to aggregate into amyloid-like fibrils in vitro, which opens future perspectives towards positioning CHK2 in cancer pathophysiology. CHK2 variants exhibited higher propensity for this conformational change, also displaying higher expression in thyroid tumors. The present findings support the utility of complementary biophysical and in silico approaches towards understanding the impact of genetic variants in protein structure and function, improving the current knowledge on CHEK2 variants’ role in FNMTC genetic basis, with prospective clinical translation.

Investigating USP42 Mutation as Underlying Cause of Familial Non-Medullary Thyroid Carcinoma.

In a family with Familial Non-Medullary Thyroid Carcinoma (FNMTC), our investigation using Whole-Exome Sequencing (WES) uncovered a novel germline USP42 mutation [p.(Gly486Arg)]. USP42 is known for regulating p53, cell cycle arrest, and apoptosis, and for being reported as overexpressed in breast and gastric cancer patients. Recently, a USP13 missense mutation was described in FNMTC, suggesting a potential involvement in thyroid cancer. Aiming to explore the USP42 mutation as an underlying cause of FNMTC, our team validated the mutation in blood and tissue samples from the family. Using immunohistochemistry, the expression of USP42, Caspase-3, and p53 was assessed. The USP42 gene was silenced in human thyroid Nthy-Ori 3-1 cells using siRNAs. Subsequently, expression, viability, and morphological assays were conducted. p53, Cyclin D1, p21, and p27 proteins were evaluated by Western blot. USP42 protein was confirmed in all family members and was found to be overexpressed in tumor samples, along with an increased expression of p53 and cleaved Caspase-3. siRNA-mediated USP42 downregulation in Nthy-Ori 3-1 cells resulted in reduced cell viability, morphological changes, and modifications in cell cycle-related proteins. Our results suggest a pivotal role of USP42 mutation in thyroid cell biology, and this finding indicates that USP42 may serve as a new putative target in FNMTC.

Identification of a Novel Germline PPP4R3A Missense Mutation Asp409Asn on Familial Non-Medullary Thyroid Carcinoma.

Familial non-medullary thyroid carcinoma (FNMTC) accounts for 3% to 9% of all thyroid cancer cases, yet its genetic mechanisms remain unknown. Our study aimed to screen and identify novel susceptibility genes for FNMTC. Whole-exome sequencing (WES) was conducted on a confirmed FNMTC pedigree, comprising four affected individuals across two generations. Variants were filtered and analyzed using ExAC and 1000 Genomes Project, with candidate gene pathogenicity predicted using SIFT, PolyPhen, and MutationTaster. Validation was performed through Sanger sequencing in affected pedigree members and sporadic patients (TCGA database) as well as general population data (gnomAD database). Ultimately, we identified the mutant PPP4R3A (NC_000014.8:g.91942196C>T, or NM_001366432.2(NP_001353361.1):p.(Asp409Asn), based on GRCH37) as an FNMTC susceptibility gene. Subsequently, a series of functional experiments were conducted to investigate the impact of PPP4R3A and its Asp409Asn missense variant in thyroid cancer. Our findings demonstrated that wild-type PPP4R3A exerted tumor-suppressive effects via the Akt-mTOR-P70 S6K/4E-BP1 axis. However, overexpression of the PPP4R3A Asp409Asn mutant resulted in loss of tumor-suppressive function, ineffective inhibition of cell invasion, and even promotion of cell proliferation and migration by activating the Akt/mTOR signaling pathway. These results indicated that the missense variant PPP4R3A Asp409Asn is a candidate susceptibility gene for FNMTC, providing new insights into the diagnosis and intervention of FNMTC.

Familial nonmedullary thyroid cancer: a case series in Iranian patients with a meta-review of case series.

Nonmedullary thyroid cancer (NMTC) comprises approximately 90% of all thyroid cancers, and about 3% to 9% of NMTC cases have a familial origin. Familial NMTC (FNMTC) in the absence of a documented familial cancer syndrome such as Cowden syndrome is characterized by the occurrence of thyroid cancer of follicular cell origin in 2 or more first-degree relatives. Whole-exome sequencing (WES) was used to identify pathogenic genetic variants in 2 Persian families with FNMTC. The purpose of this work is to assess the pathogenic status of these variants as well as the cosegregation status of the variants observed in the examined families. By analyzing WES data in the first family, SRGAP1: NM_020762: exon16: c.C1849T was identified as a pathogenic variant. This variant was confirmed by Sanger sequencing. In the second family, the variant FOXE1: NM_004473: exon1: c.531_532insCGCGA was identified but was not confirmed by Sanger sequencing. Based on the data, SRGAP1 can be a potential candidate gene for susceptibility to FNMTC in the first family. However, additional analyses like whole genome sequencing and copy number variations are required to ascertain the disease status in second family.

SAT509 The Clinical Significance of Cribriform Morular Thyroid Carcinoma

Abstract Disclosure: G. Soh: None. K. Sek: None. S. Yang: None. M. Nga: None. S. Mok: None. We present two young (aged below 30) female patients who were diagnosed with the rare cribriform morular thyroid carcinoma. Both patients presented with neck swellings and underwent total thyroidectomy for the thyroid malignancies. The histological diagnosis prompted subsequent genetic evaluation. Both patients demonstrated genotypic and phenotypic evidence of familial adenomatosis polyposis (FAP) syndrome. One of the patients had a mutation which resulted in a premature translational stop signal in the adenomatous polyposis coli (APC) gene. She was eventually diagnosed with adenocarcinoma in 2 colonic polyps and underwent a curative pan-proctocolectomy. The other patient was diagnosed clinically with FAP as she had multiple (30-40) colonic polyps which were tubular adenomas. She had a variant of unknown significance in the APC gene. She declined surgery and remained on colonoscopic surveillance. Both patients’ thyroid cancers are in clinical remission. While uncommon, diagnosing cribriform-morular thyroid carcinoma is significant as 25 to 30% of patients harbour genetic mutations in the APC gene on chromosome 5q21. This is associated with FAP syndrome, an autosomal dominant genetic syndrome characterized by young-onset colonic polyposis, usually of malignant potential. Additionally, these patients may exhibit features of Gardner’s syndrome, a subset of FAP syndrome in which patients can develop extra-colonic manifestations such as osteomas of the mandible and supernumerary teeth. Histologically, cribriform morular thyroid carcinoma are well circumscribed and show a variable combination of follicular, cribriform, papillary, trabecular, solid and morular patterns. There is nuclear and cytoplasmic staining for beta catenin, as the inactivating APC mutation causes a loss of beta catenin destruction complex, impeding beta catenin degradation and increasing its nuclear translocation. This is a key event in thyroid tumorigenesis. The diagnosis of cribriform morular thyroid carcinoma should alert the clinician about the possibility of FAP with consideration for further clinical and genetic evaluation to confirm the diagnosis. References1)Cameselle-Teijeiro, J. M., Peteiro-González, D., Caneiro-Gómez, J., Sánchez-Ares, M., Abdulkader, I., Eloy, C., Melo, M., Amendoeira, I., Soares, P., & Sobrinho-Simões, M. (2018). Cribriform-morular variant of thyroid carcinoma: A neoplasm with distinctive phenotype associated with the activation of the Wnt/β-catenin pathway. Modern Pathology, 31(8), 1168–1179. https://doi.org/10.1038/s41379-018-0070-2 2)Peiling Yang, S., & Ngeow, J. (2016). Familial non-medullary thyroid cancer: Unraveling the Genetic Maze. Endocrine-Related Cancer, 23(12). https://doi.org/10.1530/erc-16-0067 Presentation Date: Saturday, June 17, 2023

Genetics of familial non-medullary thyroid carcinoma - investigation of two families'

Genetics of familial non-medullary thyroid carcinoma - investigation of two families'

FAMILIAL NON-MEDULLARY THYROID CARCINOMA.

Familial non-medullary thyroid carcinoma (FNMTC) is defined as cancer developing in two or more first-degree relatives if predisposing factors, for example, radiation, are absent. The disease can be either syndromic, when it is a component of complex genetic syndromes, or non-syndromic (95% cases). The genetic basis of non-syndromic FNMTC is unknown; the clinical behavior of tumorsis unclear and, at times, contradictory. To analyze clinical manifestations of FNMTC and compare them with the data for sporadic papillary thyroid carcinomas in patients of the same age groups. We examined 22 patients (a "parents" group and a "children" group) suffering from the non-syndromic FNMTC. For comparison, two groups of sporadic papillary carcinomas patients of the same age were drawn up("adult" and "young"). We analyzed tumor size and frequency of the distributionby the categoryof TNM system, invasiveness, multifocality, metastases to lymph nodes, type and extent of surgical and radioiodine treatment, and prognosis according to the MACIS criterion. Whether sporadic or familial, the tumor size, metastatic potential, and invasive potential are higher in young people, asalready known. There was no significant difference between the "parents" and "adult" groups of patients in terms of tumor parameters. One exception was the higher frequency of multifocal tumors in the FNMTC patients. Meanwhile, compared to the "young" sporadic papillary carcinomas patients, the FNMTC "children" had a higher frequency of T2 tumors, metastasizing (N1a-N1ab), and multifocal tumors, but a lower frequency of carcinomas with intrathyroidal invasions.In the FNMTC "children" compared to FNMTC "parents" was a higher frequency of T2 tumors, metastasizing carcinomas, and tumors with capsular invasion. FNMTC carcinomas are more aggressive than sporadic ones, especially in patients who are first-degree relatives in a family with parents already diagnosed with the disease.

Ultrasonography screening in children and adolescents who have one parent with familial non-medullary thyroid carcinoma.

To evaluate ultrasonography (US) screening for thyroid cancer in children and adolescents who have one parent with familial non-medullary thyroid carcinoma (FNMTC) unrelated to known genetic syndromes. In this prospective study, we selected 72 children and adolescents (age ≤18 years) without a palpable thyroid nodule or history of radiation exposure, but who have one parent diagnosed with FNMTC (i.e. at least one other affected first-degree relative). The children and adolescents were evaluated by US during initial assessment and after 5 years. Initial US revealed pure cysts in five participants and nodules in seven, which were ≥5 mm in five. These patients were submitted to fine needle aspiration, which revealed benign cytology in four and a follicular lesion of undetermined significance in one. Fine needle aspiration was repeated in the last case and in one case with benign cytology but suspicious US. The second cytology was benign in both cases. After 5 years, another two participants with initially normal US had nodules <5 mm in the absence of suspicious findings. The frequency of lesions detected by US was not associated with participant sex or age, number of relatives with thyroid cancer (2 or 3), maternal or paternal origin of tumour, or age of the relatives at diagnosis. The present results suggest that US screening is not necessary in children or adolescents when one parent has a diagnosis of FNMTC (≥2 affected relatives).

Does the length of a polyalanine tract in the FOXE1 gene impact the course of familial non-medullary thyroid cancer?

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Clinical characteristics and prognosis of familial nonmedullary thyroid carcinoma

IntroductionFamilial non-medullary thyroid carcinoma (FNMTC) is defined by the presence of 2 or more first-degree family members with differentiated thyroid carcinoma (DTC). The aim of this study is to compare clinicopathological features and prognosis of FNMTC and sporadic carcinoma (SC). Materials and methodsRetrospective study of DTC included in the hospital database during the period 1990–2018. ResultsA total of 927 patients were analyzed, 61 of them were FNMTC, with a mean follow-up of 9.7 ± 6.5 years. The prevalence of FNMTC was 6.6%, with a lower TNM staging presentation (P = 0.003) consequence of a higher proportion of tumors smaller than 2 cm (P = 0.003), combined with a greater multifocality (P = 0.034) and papillary histologic subtype (P = 0.022) compared to SC. No significant differences in age at diagnosis (P = 0.347), gender (P = 0.406), neither in other aggressiveness markers (bilaterality, extrathyroidal extension, lymph node involvement and metástasis) were detected. Rate of persistence/recurrence (P = 0.656), disease-free survival (P = 0.929) and mortality caused by the tumor itself (P = 0.666) were comparable. Families with ≥3 affected relatives, had smaller tumors (P = 0.005), more multifocality (P = 0.040) and bilaterality (P = 0.002), as well as a higher proportion of males (P = 0.020). Second generation patients present earlier FNMTC compared to those of the first generation (P = 0.001). ConclusionIn our study FNMTC presents a lower TNM staging, higher multifocality and papillary variant, with similar aggressiveness and prognosis compared to SC.

Risk of Second Malignant Neoplasm in Familial Non-Medullary Thyroid Cancer Patients.

IntroductionSurvival rates in patients with non-medullary thyroid carcinoma (NMTC) are high, increasing the possibility to develop a second malignant neoplasm (SMN). Many studies investigated the relationship between increased risk of SMN in NMTC patients treated with radioiodine, but few data are available about the impact of family history (FH) of thyroid cancer on SMN risk.PurposeTo assess the risk of SMN in a large cohort of sporadic and familial NMTC using the standardized incidence ratio (SIR).Patients and methodsWe studied 918 NMTC patients (73.9% female patients) followed for a median follow-up of 9 years. In 798/918 (86.9%) patients, NMTC was sporadic, while the remaining 120 (13.1%) were familial NMTC (FNMTC).ResultsWe identified 119/918 (13%) patients with SMN in association with NMTC. NMTCs had an increased risk of SMN when compared to the general population (SIR 2.1, 95% CI 1.7–2.5). The rate of SMN for all sites was significantly higher in familial compared to sporadic NMTC (20% versus 11.9%, p = 0.01), primarily driven by families with more than two affected members. The risk of SMN was remarkably higher for breast cancer, especially in familial cases (SIR 22.03, 95% CI 14.4–41.2) compared to sporadic cases (SIR:17, 95% CI 11.9–24.6).ConclusionsNMTC patients have a higher risk of SMN compared to the general population and this risk is much higher in patients with FNMTC. This observation raises the hypothesis that genetic risk factors for a first cancer may predispose to SMN, especially among individuals with familial clustering of the same or other tumors.

Identification of NID1 as a novel candidate susceptibility gene for familial non-medullary thyroid carcinoma using whole-exome sequencing.

The genetics underlying non-syndromic familial non-medullary thyroid carcinoma (FNMTC) is still poorly understood. To identify susceptibility genes for FNMTC, we performed whole-exome sequencing (WES) in a Brazilian family affected by papillary thyroid carcinoma (PTC) in three consecutive generations. WES was performed in four affected and two unaffected family members. Manual inspection in over 100 previously reported susceptibility genes for FNMTC showed that no variants in known genes co-segregated with disease phenotype in this family. Novel candidate genes were investigated using PhenoDB and filtered using Genome Aggregation (gnomAD) and Online Archive of Brazilian Mutations (ABraOM) population databases. The missense variant p.Ile657Met in the NID1 gene was the only variant that co-segregated with the disease, while absent in unaffected family members and controls. The allele frequency for this variant was <0.0001 in the gnomAD and ABbraOM databases. In silico analysis predicted the variant to be deleterious or likely damaging to the protein function. Somatic mutations in NID1 gene were found in nearly 500 cases of different cancer subtypes in the intOGen platform. Immunohistochemistry analysis showed NID1 expression in PTC cells, while it was absent in normal thyroid tissue. Our findings were corroborated using data from the TCGA cohort. Moreover, higher expression of NID1 was associated with higher likelihood of relapse after treatment and N1b disease in PTCs from the TCGA cohort. Although replication studies are needed to better understand the role of this variant in the FNMTC susceptibility, the NID1 variant (c.1971T>G) identified in this study fulfills several criteria that suggest it as a new FNMTC predisposing gene.

Comparison Between Clinicopathological Characteristics, BRAF V600E and TERT Promoter Mutation of Familial Non-Medullary Thyroid Carcinomas, and Sporadic Case.

BackgroundIt has been debated whether familial non-medullary thyroid carcinoma (FNMTC) is more aggressive and has a worse prognosis than sporadic non-medullary thyroid carcinoma (SNMTC). Our aim was to compare the invasiveness and prognosis of FNMTC and SNMTC by their biological behavior and molecular changes.Method and MaterialOur group mainly compared 106 patients with FNMTC whom have complete clinicopathological data during 2011–2019 in West China Hospital, Sichuan University, and 212 randomly selected cases with SNMTC were included to compare their biological behavior, recurrence and mortality, and molecular expression of BRAF V600E and TERT promoter. At the same time, FNMTC cases were divided into four subgroups, namely, two affected members group, three or more affected members, parent/offspring group, and sibling group, and they were compared with SNMTC separately to analyze the difference in their invasiveness and prognosis.ResultsWe found that the mean tumor size of FNMTC (0.96 ± 0.53cm) was smaller than that of SNMTC (1.15 ± 0.72 cm) (p = 0.020), while no significant difference in the incidence of other clinicopathological factors, including bilateral growth, capsular invasion, with thyroid nodular goiter or not, multifocality, lymph node metastasis, extrathyroidal extension, iodine 131 treatments, T stage, and American Joint Committee on Cancer (AJCC) stage, was observed between FNMTC and SNMTC (p > 0.05), between each FNMTC subgroup (p > 0.05), and between each FNMTC subgroup and SNMTC (p > 0.05). There was no significant difference in recurrence, mortality, and BRAF V600E and TERT promoter mutation between FNMTC and SNMTC, among which 50/60 (83.33%) of FNMTC patients had BRAF V600E mutation and 1/32 (3.13%) had TERT promoter mutation, while the mutation rates of SNMTC were 93/108 (86.11%) and 3/64 (4.69%) (p > 0.05).ConclusionThere was no significant difference in invasiveness and prognosis between FNMTC and SNMTC by biological behavior, patient survival, and molecular level comparison.

Preoperative Ultrasonography in the Evaluation of Suspected Familial Non-Medullary Thyroid Cancer: Are We Able to Predict Multifocality and Extrathyroidal Extension?

Family history of thyroid cancer increases the risk of harboring thyroid malignancies that end up having extrathyroidal extension (ETE) and multifocality on histology; some authors suggest a more aggressive surgical approach. Their pre-operative identification could allow more conservative surgical procedures if none of these features are suspected. Our aim was to assess if neck ultrasonography could identify or exclude multifocality or ETE in these patients to tailor the extent of surgery. This retrospective study included patients with previous thyroid surgery, ≥1 first-grade relative with thyroid cancer, and who had undergone pre-surgical ultrasound. ETE was suspected in the case of thyroid border interruption or gross invasion of perithyroidal tissues. Multiple suspicious nodules were defined as suspicion of multifocal cancer. The cohort consisted of 45 patients (median age 49 years, 40 with thyroid cancer, 30 females). The positive predictive value of ultrasonography in predicting multifocality and ETE was 57.14% (25.25–84.03) and 41.67% (21.5–65.1%), respectively, while the negative predictive values were 63.2% (56.4–69.4%) and 72.7% (63.3–80.5%). Pre-operative ultrasound examination is unable to reliably identify or exclude multifocal disease or extrathyroidal extension. In patients scheduled for surgery and with a first-degree relative affected by DTC, a “negative” pre-operative US report does not exclude the potential finding of multifocality and ETE at final histopathology.

Germ-line mutations in WDR77 predispose to familial papillary thyroid cancer

The inheritance of predisposition to nonsyndromic familial nonmedullary thyroid cancer (FNMTC) remains unclear. Here, we report six individuals with papillary thyroid cancer (PTC) in two unrelated nonsyndromic FNMTC families. Whole-exome sequencing revealed two germ-line loss-of-function variants occurring within a 28-bp fragment of WDR77, which encodes a core member of a transmethylase complex formed with the protein arginine methyltransferase PRMT5 that is responsible for histone H4 arginine 3 dimethylation (H4R3me2) in frogs and mammals. To date, the association of WDR77 with susceptibility to cancer in humans is unknown. A very rare heterozygous missense mutation (R198H) in WDR77 exon 6 was identified in one family of three affected siblings. A heterozygous splice-site mutation (c.619+1G > C) at the 5' end of intron 6 is present in three affected members from another family. The R198H variant impairs the interaction of WDR77 with PRMT5, and the splice-site mutation causes exon 6 skipping and results in a marked decrease in mutant messenger RNA, accompanied by obviously reduced H4R3me2 levels in mutation carriers. Knockdown of WDR77 results in increased growth of thyroid cancer cells. Whole-transcriptome analysis of WDR77 mutant patient-derived thyroid tissue showed changes in pathways enriched in the processes of cell cycle promotion and apoptosis inhibition. In summary, we report WDR77 mutations predisposing patients to nonsyndromic familial PTC and link germ-line WDR77 variants to human malignant disease.

Co-Occurrence of Familial Non-Medullary Thyroid Cancer (FNMTC) and Hereditary Non-Polyposis Colorectal Cancer (HNPCC) Associated Tumors-A Cohort Study.

Familial non-medullary thyroid cancer (FNMTC) is a form of endocrine malignancy exhibiting an autosomal dominant mode of inheritance with largely unknown germline molecular mechanism. Hereditary nonpolyposis colorectal cancer syndrome (HNPCC) is another hereditary autosomal dominant cancer syndrome which, if proven to be caused by germline mutations in mismatch repair genes (MMR)—MLHL, MSH2, MSH6, PMS2, and EPCAM—is called Lynch syndrome (LS). LS results in hereditary predisposition to a number of cancers, especially colorectal and endometrial cancers. Tumors in LS are characterized by microsatellite instability (MSI) and/or loss of MMR protein expression in immunohistochemistry (IHC). MSI is a rare event in thyroid cancer (TC), although it is known to occur in up to 2.5% of sporadic follicular TC cases. There are limited data on the role of germline MMR variants FNMTC. The goal of this study was to analyze the potential clinical and molecular association between HNPCC and FNMTC. We performed a cohort study analyzing the demographic, clinical, and pathologic data of 43 kindreds encompassing 383 participants (104 affected, 279 unaffected), aged 43.5 [7-99] years with FNMTC, and performed high-throughput whole-exome sequencing (WES) of peripheral blood DNA samples of selected 168 participants (54 affected by FNMTC and 114 unaffected). Total affected by thyroid cancer members per family ranged between 2 and 9 patients. FNMTC was more prevalent in women (68.3%) and characterized by a median tumor size of 1.0 [0.2-5.0] cm, multifocal growth in 44%, and gross extrathyroidal extension in 11.3%. Central neck lymph node metastases were found in 40.3% of patients at presentation, 12.9% presented with lateral neck lymph node metastases, and none had distant metastases. Family history screening revealed one Caucasian family meeting the clinical criteria for FNMTC and HNPCC, with five members affected by FNMTC and at least eight individuals reportedly unaffected by HNPCC-associated tumors. In addition, two family members were affected by melanoma. Genome Analysis Tool Kit (GATK) pipeline was used in variant analysis. Among 168 sequenced participants, a heterozygous missense variant in the MSH2 gene (rs373226409; c.2120G>A; p.Cys707Tyr) was detected exclusively in FNMTC- HNPCC- kindred. In this family, the sequencing was performed in one member affected by FNMTC, HPNCC-associated tumors and melanoma, one member affected solely by HNPCC-associated tumor, and one member with FNMTC only, as well as seven unaffected family members. The variant was present in all three affected adults, and in two unaffected children of the affected member, under the age of 18 years, and was absent in non-affected adults. This variant is predicted to be damaging/pathogenic in 17/20 in-silico models. However, immunostaining performed on the thyroid tumor tissue of two affected by FNMTC family members revealed intact nuclear expression of MSH2, and microsatellite stable status in both tumors that were tested. Although the MSH2 p.Cys707Tyr variant is rare with a minor allele frequency (MAF) of 0.00006 in Caucasians; it is more common in the South Asian population at 0.003 MAF. Therefore, the MSH2 variant observed in this family is unlikely to be an etiologic factor of thyroid cancer and a common genetic association between FNMTC and HNPCC has not yet been identified. This is the first report known to us on the co-occurrence of FNMTC and HNPCC. The co-occurrence of FNMTC and HNPCC-associated tumors is a rare event and although presented in a single family in our large FNMTC cohort, a common genetic background between the two comorbidities could not be established.

Inherited Thyroid Tumors With Oncocytic Change.

Familial non-medullary thyroid carcinoma (FNMTC) corresponds to 5-10% of all follicular cell-derived carcinoma (FCDTC). Oncocytic thyroid tumors have an increased incidence in the familial context in comparison with sporadic FCDTC, encompassing benign and malignant tumors in the same family presenting with some extent of cell oxyphilia. This has triggered the interest of our and other groups to clarify the oncocytic change, looking for genetic markers that could explain the emergence of this phenotype in thyroid benign and malignant lesions, focusing on familial aggregation. Despite some advances regarding the identification of the gene associated with retinoic and interferon-induced mortality 19 (GRIM-19), as one of the key candidate genes affected in the “Tumor with Cell Oxyphilia” (TCO) locus, most of the mutations follow a pattern of “private mutations”, almost exclusive to one family. Moreover, no causative genetic alterations were identified so far in most families. The incomplete penetrance of the disease, the diverse benign and malignant phenotypes in the affected familial members and the variable syndromic associations create an additional layer of complexity for studying the genetic alterations in oncocytic tumors. In the present review, we summarized the available evidence supporting genomic-based mechanisms for the oncocytic change, particularly in the context of FNMTC. We have also addressed the challenges and gaps in the aforementioned mechanisms, as well as molecular clues that can explain, at least partially, the phenotype of oncocytic tumors and the respective clinico-pathological behavior. Finally, we pointed to areas of further investigation in the field of oncocytic (F)NMTC with translational potential in terms of therapy.