Distinct loci on chromosome 1q21 and 6q22 predispose to familial nonmedullary thyroid cancer: A SNP array-based linkage analysis of 38 families

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.

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.

Potential values of circulating tumor cell for detection of recurrence in patients of thyroid cancer: a diagnostic meta-analysis

Background

Several studies have reported that circulating tumor cells (CTCs) are a promising marker for the diagnosis of thyroid cancer (TC) with recurrence or distant metastasis (DMs). However, some studies emerged with conflicting results. Therefore, we provide a meta-analysis to evaluate the diagnostic performance of CTC for detection of recurrence in patients of TC.

Methods

We searched PubMed, Web of Science, Cochrane library with the keywords “thyroid cancer” and “circulating tumor cells”. Data extraction and risk of bias assessment were performed independently by two reviewers. The summary receiver operating characteristic curve (SROC) and other parameters were adopted to summarize the overall test performance. The sensitivity of CTCs in the detection of recurrent TC was reviewed. All analyses were performed by STATA 12.0 and Meta-disc software.

Results

For CTCs expressing epithelial cell adhesion molecule (EpCAM), seven studies were included in our meta-analysis. Pooled sensitivity, specificity, and diagnostic odds ratio were 0.71 (95% CI: 0.63–0.78), 0.89 (95% CI: 0.84–0.94), and 26.75 (95% CI: 9.11–78.53); 0.78 (95% CI: 0.65–0.89), 0.88 (95% CI: 0.76–0.96), and 40.01 (95% CI: 10.49–152.63) for CTCs expressing thyroid stimulating hormone receptor (TSHR). The area under the SROC for EpCAM and TSHR were both 0.91.

Conclusion

CTC was a reliable marker for the diagnosis of TC patients with recurrence and DMs, and the sensitivity of CTCs expressing TSHR was higher than that of EpCAM. Additional research is warranted in order to establish uniformity in international guidelines, make up the drawbacks of conventional diagnostic methods and to prevent futile surgery.

Genetic susceptibility to hereditary non-medullary thyroid cancer

Non-medullary thyroid cancer (NMTC) is the most common type of thyroid cancer. With the increasing incidence of NMTC in recent years, the familial form of the disease has also become more common than previously reported, accounting for 5-15% of NMTC cases. Familial NMTC is further classified as non-syndromic and the less common syndromic FNMTC. Although syndromic NMTC has well-known genetic risk factors, the gene(s) responsible for the vast majority of non-syndromic FNMTC cases are yet to be identified. To date, several candidate genes have been identified as susceptibility genes in hereditary NMTC. This review summarizes genetic predisposition to non-medullary thyroid cancer and expands on the role of genetic variants in thyroid cancer tumorigenesis and the level of penetrance of NMTC-susceptibility genes.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Susceptibility Genes and Chromosomal Regions Associated With Non-Syndromic Familial Non-Medullary Thyroid Carcinoma: Some Pathogenetic and Diagnostic Keys

Thyroid cancer is the malignant tumor that is increasing most rapidly in the world, mainly at the expense of sporadic papillary thyroid carcinoma. The somatic alterations involved in the pathogenesis of sporadic follicular cell derived tumors are well recognized, while the predisposing alterations implicated in hereditary follicular tumors are less well known. Since the genetic background of syndromic familial non-medullary carcinoma has been well established, here we review the pathogenesis of non-syndromic familial non-medullary carcinoma emphasizing those aspects that may be useful in clinical and pathological diagnosis. Non-syndromic familial non-medullary carcinoma has a complex and heterogeneous genetic basis involving several genes and loci with a monogenic or polygenic inheritance model. Most cases are papillary thyroid carcinoma (classic and follicular variant), usually accompanied by benign thyroid nodules (follicular thyroid adenoma and/or multinodular goiter). The possible diagnostic and prognostic usefulness of the changes in the expression and/or translocation of various proteins secondary to several mutations reported in this setting requires further confirmation. Given that non-syndromic familial non-medullary carcinoma and sporadic non-medullary thyroid carcinoma share the same morphology and somatic mutations, the same targeted therapies could be used at present, if necessary, until more specific targeted treatments become available.

A pathogenic variant in CHEK2 shows a founder effect in Portuguese Roma patients with thyroid cancer

PURPOSE

Germline mutations in DNA repair-related genes have been recently reported in cases with familial non-medullary thyroid carcinoma (FNMTC). A Portuguese family from the Roma ethnic group with four members affected with papillary thyroid carcinoma (PTC), and three members with multinodular goiter (MNG) was identified. The aim of this study was to investigate the involvement of DNA repair-related genes in the etiology of FNMTC in this family and in the Roma ethnic group.

METHODS

Ninety-four hereditary cancer predisposition genes were analyzed through next-generation sequencing. Sanger sequencing was used for variant confirmation and screening. Twelve polymorphic markers were genotyped for haplotype analysis in the CHEK2 locus.

RESULTS

A germline pathogenic frameshift variant in the CHEK2 gene [c.596dupA, p.(Tyr199Ter)] was detected in homozygosity in the proband (PTC) and in his brother (MNG), being heterozygous in his mother (PTC), two sisters (PTC), and one nephew (MNG). This variant was absent in 100 general population controls. The screening of the CHEK2 variant was extended to other Roma individuals, being detected in 2/33 Roma patients with thyroid cancer, and in 1/15 Roma controls. Haplotype segregation analysis identified a common ancestral core haplotype (Hcac), covering 10 Mb in the CHEK2 locus, shared by affected CHEK2 variant carriers. Analysis of 62 individuals CHEK2 wild-type indicated that none presented the Hcac haplotype. The estimated age for this variant suggested that it was transmitted by a relatively recent common ancestor.

CONCLUSIONS

We identified a founder CHEK2 pathogenic variant, which is likely to underlie thyroid cancer and other cancer manifestations in the Roma population.

Inherited Follicular Epithelial-Derived Thyroid Carcinomas: From Molecular Biology to Histological Correlates

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be "sporadic" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.

Genetic Mutations and Variants in the Susceptibility of Familial Non-Medullary Thyroid Cancer

Thyroid cancer is the most frequent endocrine malignancy with the majority of cases derived from thyroid follicular cells and caused by sporadic mutations. However, when at least two or more first degree relatives present thyroid cancer, it is classified as familial non-medullary thyroid cancer (FNMTC) that may comprise 3-9% of all thyroid cancer. In this context, 5% of FNMTC are related to hereditary syndromes such as Cowden and Werner Syndromes, displaying specific genetic predisposition factors. On the other hand, the other 95% of cases are classified as non-syndromic FNMTC. Over the last 20 years, several candidate genes emerged in different studies of families worldwide. Nevertheless, the identification of a prevalent polymorphism or germinative mutation has not progressed in FNMTC. In this work, an overview of genetic alteration related to syndromic and non-syndromic FNMTC is presented.

Familial non-medullary thyroid carcinoma: clinico-pathological features, current knowledge and novelty regarding genetic risk factors

Familial non-medullary thyroid cancer (FNMTC) constitutes 3-9% of all thyroid cancers and occurs in two or more first-degree relatives in the absence of predisposing environmental factors. Out of all FNMTC cases, only 5% are represented by syndromic forms (Gardner's Syndrome, familial adenomatous polyposis, Cowden's Syndrome, Carney complex 1, Werner's Syndrome and DICER1 syndrome), in which thyroid cancer occurs as a minor component and the genetic alterations are well-known. The non-syndromic forms represent the majority of all FNMTCs (95%), and the thyroid cancer is the predominant feature. Several low penetration susceptibility risk loci or genes (i.e. TTF1, FOXE1, SRGAP1, SRRM2, HABP2, MAP2K5, and DUOX2), here fully reviewed, have been proposed in recent years with a possible causative role, though the results are still not conclusive or reliable. FNMTC is indistinguishable from sporadic non-medullary thyroid cancer (sNMTC), which means that FNMTC cannot be diagnosed until at least one of the patient's first-degree relatives is affected by tumor. Some studies reported that the non-syndromic FNMTC is more aggressive than the sNMTC, being characterized by a younger age of onset and a higher rate of multifocal and bilateral tumors, extrathyroidal extension, lymph node metastasis, and recurrence. On the contrary, other studies did not find clinical differences between non-syndromic FNMTCs and sporadic cases. Here, I reported an extensive review on genetic and clinico-pathological features of the FNMTC, with particular attention on novel genetic risk factors for non-syndromic forms.

Lack of Mutations in POT1 Gene in Selected Families with Familial Non-Medullary Thyroid Cancer

To date, the genes involved in familial non-medullary thyroid cancer (FNMTC) remain poorly understood, with the exception of syndromic cases of FNMTC. It has been proposed that germline mutations in telomere-related genes, such as POT1, described in familial melanoma might also predispose individuals to thyroid cancer, requiring further research. We aimed to identify germline mutations in POT1 in selected FNMTC families (with at least three affected members) without a history of other cancers or other features, and to describe the clinical characteristics of these families. Sequencing of the 5'UTR and coding regions of POT1 was performed in seven affected people (index cases) from seven families with FNMTC. In addition, we performed whole-exome sequencing (WES) of DNA from 10 affected individuals belonging to four of these families. We did not find germline variants of interest in POT1 by Sanger sequencing or WES. We neither found putative causative mutations in genes previously described as candidate genes for FNMTC in the 4 families studied by WES. In our study, no germline potentially pathogenic mutations were detected in POT1, minimizing the possibilities that this gene could be substantially involved in non-syndromic FNMTC.

Germline Mutations in Familial Papillary Thyroid Cancer

Thyroid cancer, predominantly of papillary histology (PTC), is a common cancer mostly diagnosed sporadically. Hereditary PTC is encountered in ~ 5% of cases and may present at an earlier age, with greater risks of metastasis and recurrence, compared with sporadic cases. The molecular basis of hereditary PTC is unknown in most cases. In this study, the genetic basis of hereditary PTC in three Brazilian families was investigated. Whole exome sequencing (WES) was carried out for probands in each family, and validated, pathogenic/likely pathogenic sequence variants (P/LPSVs) were genotyped in additional family members to establish their putative pathogenic role. Overall, seven P/LPSVs in seven novel genes were detected: p.D283N*ANXA3, p.Y157S*NTN4, p.G172W*SERPINA1, p.G188S*FKBP10, p.R937C*PLEKHG5, p.L32Q*P2RX5, and p.Q76*SAPCD1. These results indicate that these novel genes are seemingly associated with hereditary PTC, but extension and validation in other PTC families are required.

A Truncating Germline Mutation of TINF2 in Individuals with Thyroid Cancer or Melanoma Results in Longer Telomeres

Background: Our genome sequencing analysis revealed a frameshift mutation in the shelterin gene TINF2 in a large family with individuals affected with papillary thyroid carcinoma (PTC) and melanoma. Here, we further characterized the mutation and screened for coding variants in the 6 shelterin genes in 24 families. Methods: Sanger sequencing was performed to screen for the TINF2 mutation in the key family. Quantitative reverse transcription-polymerase chain reaction (PCR) was used for TINF2 gene expression analysis. Exogenous expression and co-immunoprecipitation techniques were used for assessing TINF2 binding to TERF1. Relative telomere length (RTL) was quantified in DNAs from lymphocytes by using quantitative real-time PCR. Whole exome sequencing (WES) was performed in seven families with individuals affected with PTC and other cancer types. Screening for DNA variants in shelterin genes was performed by using whole genome sequencing data from 17 families and WES data from 7 further families. Results: The TINF2 mutation (TINF2 p.Trp198fs) showed complete co-segregation with PTC and melanoma in the key family. The mutation is not reported in databases and not identified in 23 other families we screened. The expression of TINF2 was borderline reduced in individuals with the mutation. The truncated TINF2 protein showed abolished binding to TERF1. The RTL in the individuals with the mutation was significantly longer when compared with those without the mutation from the same family as well as compared with 62 healthy controls. Among the 24 families, we identified 3 missense and 1 synonymous variant(s) in 2 shelterin genes (TINF2 and ACD). Conclusions: The rare frameshift mutation in the TINF2 gene and the associated longer telomere length suggest that dysregulated telomeres could be a mechanism predisposing to PTC and melanoma. DNA coding variants in shelterin genes are rare. Further studies are required to evaluate the roles of variants in shelterin genes in thyroid cancer and melanoma.

NOP53 as A Candidate Modifier Locus for Familial Non-Medullary Thyroid Cancer

Nonsyndromic familial non-medullary thyroid cancer (FNMTC) represents 3–9% of thyroid cancers, but the susceptibility gene(s) remain unknown. We designed this multicenter study to analyze families with nonsyndromic FNMTC and identify candidate susceptibility genes. We performed exome sequencing of DNA from four affected individuals from one kindred, with five cases of nonsyndromic FNMTC. Single Nucleotide Variants, and insertions and deletions that segregated with all the affected members, were analyzed by Sanger sequencing in 44 additional families with FNMTC (37 with two affected members, and seven with three or more affected members), as well as in an independent control group of 100 subjects. We identified the germline variant p. Asp31His in NOP53 gene (rs78530808, MAF 1.8%) present in all affected members in three families with nonsyndromic FNMTC, and not present in unaffected spouses. Our functional studies of NOP53 in thyroid cancer cell lines showed an oncogenic function. Immunohistochemistry exhibited increased NOP53 protein expression in tumor samples from affected family members, compared with normal adjacent thyroid tissue. Given the relatively high frequency of the variant in the general population, these findings suggest that instead of a causative gene, NOP53 is likely a low-penetrant gene implicated in FNMTC, possibly a modifier.

Familial non-medullary thyroid cancer: unraveling the genetic maze

Familial non-medullary thyroid cancer (FNMTC) constitutes 3-9% of all thyroid cancers. Out of all FNMTC cases, only 5% in the syndromic form has well-studied driver germline mutations. These associated syndromes include Cowden syndrome, familial adenomatous polyposis, Gardner syndrome, Carney complex type 1, Werner syndrome and DICER1 syndrome. It is important for the clinician to recognize these phenotypes so that genetic counseling and testing can be initiated to enable surveillance for associated malignancies and genetic testing of family members. The susceptibility chromosomal loci and genes of 95% of FNMTC cases remain to be characterized. To date, 4 susceptibility genes have been identified (SRGAP1 gene (12q14), TITF-1/NKX2.1 gene (14q13), FOXE1 gene (9q22.33) and HABP2 gene (10q25.3)), out of which only the FOXE1 and the HABP2 genes have been validated by separate study groups. The causal genes located at the other 7 FNMTC-associated chromosomal loci (TCO (19q13.2), fPTC/ PRN (1q21), FTEN (8p23.1-p22), NMTC1 (2q21), MNG1 (14q32), 6q22, 8q24) have yet to be identified. Increasingly, gene regulatory mechanisms (miRNA and enhancer elements) are recognized to affect gene expression and FNMTC tumorigenesis. With newer sequencing technique, along with functional studies, there has been progress in the understanding of the genetic basis of FNMTC. In our review, we summarize the FNMTC studies to date and provide an update on the recently reported susceptibility genes including novel germline SEC23B variant in Cowden syndrome, SRGAP1 gene, FOXE1 gene and HABP2 genes in non-syndromic FNMTC.

Burkitt-Type Acute Lymphoblastic Leukemia With Precursor B-Cell Immunophenotype and Partial Tetrasomy of 1q: A Case Report

Burkitt-type acute lymphoblastic leukemia (B-ALL) is thought as a variant of Burkitt lymphoma/leukemia and derived from mature B-cell lymphoblast.B-ALL was developed in a 10-year-old girl. Two characteristics were apparent in this case. First, the lymphoblastic cells were positive for CD10, CD19, CD20, and CD22, but negative for terminal deoxynucleotidyl transferase and surface immunoglobulins, indicating a B-cell immunophenotype. The detection of t(8;14)(q24;q32) with a chromosomal analysis is required for a diagnosis of B-ALL. Second, der(1)(pter → q32.1::q32.1 → q21.1::q11 → qter) was detected, in which 1q21.1 to 1q32.1 was inverted and inserted. Finally, partial tetrasomy of 1q was also present. Because B-ALL with abnormal chromosome 1 has been reported poor outcome, the usual chemotherapy for stage 4 Burkitt lymphoma with added rituximab was administered for our patient.We report B-ALL with precursor B-cell immunophenotype and interesting partial tetrasomy of 1q.

Diagnosis and Management of Hereditary Thyroid Cancer

Thyroid cancers are largely divided into medullary (MTC) and non-medullary (NMTC) cancers , depending on the cell type of origin. Familial non-medullary thyroid cancer (FNMTC) comprises about 5-15% of NMTC and is a heterogeneous group of diseases, including both non-syndromic and syndromic forms. Non-syndromic FNMTC tends to manifest papillary thyroid carcinoma , usually multifocal and bilateral . Several high-penetrance genes for FNMTC have been identified, but they are often confined to a few or single families, and other susceptibility loci appear to play a small part, conferring only small increments in risk. Familial susceptibility is likely to be due to a combination of genetic and environmental influences. The current focus of research in FNMTC is to characterise the susceptibility genes and their role in carcinogenesis. FNMTC can also occur as a part of multitumour genetic syndromes such as familial adenomatous polyposis , Cowden's disease , Werner's syndrome and Carney complex . These tend to present at an early age and are multicentric and bilateral with distinct pathology. The clinical evaluation of these patients is similar to that for most patients with a thyroid nodule. Medullary thyroid cancer (MTC) arises from the parafollicular cells of the thyroid which release calcitonin. The familial form of MTC accounts for 20-25% of cases and presents as a part of the multiple endocrine neoplasia type 2 (MEN 2) syndromes or as a pure familial MTC (FMTC). They are caused by germline point mutations in the RET oncogene on chromosome 10q11.2. There is a clear genotype-phenotype correlation, and the aggressiveness of FMTC depends on the specific genetic mutation, which should determine the timing of surgery.

Thyroid cancer GWAS identifies 10q26.12 and 6q14.1 as novel susceptibility loci and reveals genetic heterogeneity among populations

Thyroid cancer is the most heritable cancer of all those not displaying typical Mendelian inheritance. However, most of the genetic factors that would explain the high heritability remain unknown. Our aim was to identify additional common genetic variants associated with susceptibility to this disease. In order to do so, we performed a genome-wide association study in a series of 398 cases and 502 controls from Spain, followed by a replication in four well-defined Southern European case-control collections contributing a total of 1,422 cases and 1,908 controls. The association between the variation at the 9q22 locus near FOXE1 and thyroid cancer risk was consistent across all series, with several SNPs identified (rs7028661: OR = 1.64, p = 1.0 × 10(-22) , rs7037324: OR = 1.54, p = 1.2 × 10(-17) ). Moreover, the rare alleles of three SNPs (rs2997312, rs10788123 and rs1254167) at 10q26.12 showed suggestive evidence of association with higher risk of the disease (OR = 1.35, p = 1.2 × 10(-04) , OR = 1.26, p = 5.2 × 10(-04) and OR = 1.38, p = 5.9 × 10(-05) , respectively). Finally, the rare allele of rs4075570 at 6q14.1 conferred protection in the series studied (OR = 0.82, p = 2.0 × 10(-04) ). This study suggests that heterogeneity in genetic susceptibility between populations is a key feature to take into account when exploring genetic risk factors related to this disease.

Single-center study of familial papillary thyroid cancer in China: surgical considerations

Background

Whether familial papillary thyroid cancer (FPTC) is more aggressive than sporadic counterpart remains elusive, and the optimal clinical approach for FPTC is yet to be established. In this study, we investigated familial occurrence of PTC in China and reviewed our experience of its surgical treatment.

Methods

The clinical records of 248 consecutive patients with an established diagnosis of PTC who were admitted to Nanfang Hospital for thyroidectomy between January 2011 and June 2013 were analyzed in this study. Patients included 66 males and 182 females, aged 11 to 76 years.

Results

Twenty-two patients (8.9%) with a positive family history were confirmed. Patients with FPTC had a predilection for female subjects and tended to be younger than other patients, but the difference was not significant (P = 0.0514 and P = 0.168). They were more likely to present large tumors (P = 0.0024), multifocality (familial vs. sporadic: 54.50% vs. 26.50%; P < 0.006), local invasion (81.8% vs. 23.9%; P < 0.001), and malignant lymph nodes (63.6% vs. 33.6%; P = 0.005). Univariate and multivariate analyses identified that a positive family history was an independent risk factor for local invasion (OR: 5.683; 95% CI: 2.056 to 15.707; P = 0.001), malignant lymph nodes (OR: 3.005; 95% CI: 1.046 to 8.630; P = 0.041) in FPTC patients. Kaplan-Meier survival curves revealed that an aggressive surgical strategy was associated with a better relapse-free survival than conventional one (P = 0.032).

Conclusions

FPTC is more likely to possess aggressive features than sporadic counterparts. Thus, screening of at-risk families is essential to aid in earlier recognition. An aggressive surgical strategy appeared to be the more effective therapy. However, sufficient detailed interrogation and long-term follow-up of the patients and their family are necessary for providing individualized recommendations for clinical management.

Genetic predisposition for nonmedullary thyroid cancer

Nonmedullary thyroid cancer (NMTC) can be sporadic or can occur as a component cancer as part of several well-described hereditary cancer syndromes. NMTC, particularly papillary thyroid cancer, also can occur by itself in families and is often termed familial NMTC or familial papillary thyroid cancer. The occurrence of NMTC in families, along with extensive population-based evidence from patients with sporadic thyroid cancer, together suggest that NMTC has a strong genetic component, only a small proportion of which has been characterized to date. Advances in genetic and genomic technology have rapidly advanced our understanding of the complex nature of NMTC susceptibility, although much remains to be explained. Herein, we describe the current state of knowledge, starting with a brief review of hereditary syndromic causes and moving on to describe recent data using modern genomic approaches to identifying genes involved in the predisposition to NMTC.

Familial vs sporadic papillary thyroid carcinoma: a matched-case comparative study showing similar clinical/prognostic behaviour

OBJECTIVE

Familial non-medullary thyroid cancer has been proposed as an aggressive clinical entity. Our aim in this study is to investigate potential distinguishing features as well as the biological and clinical aggressiveness of familial vs sporadic papillary thyroid carcinoma (PTC). We assessed clinicopathological characteristics, outcome measures and DNA ploidy.

DESIGN

A matched-case comparative study.

METHODS

A series of patients with familial PTC (n=107) and two subgroups, one with three or more affected elements (n=32) and another including index cases only (n=61), were compared with patients with sporadic PTC (n=107), matched by age, gender, pTNM disease extension and approximate follow-up duration. Histological variant, extrathyroidal extension, vascular invasion, tumour multifocality and bilateral growth were evaluated. Ploidy pattern was analysed in available samples by DNA flow cytometry. The probabilities of disease-free survival (DFS) and overall survival (OS) were estimated according to the Kaplan-Meier (K-M) method.

RESULTS

No patient with familial PTC died of disease during follow-up (median, 72 months), contrarily to five patients (4.7%) (P=0.06) with sporadic PTC (median, 90 months). There was a significantly higher tumour multifocality in familial PTC (index cases subgroup) vs sporadic PTC (P=0.035), and a trend, in the familial PTC cohort with three or more affected elements, to show extrathyroidal extension (P=0.054) more frequently. No difference was observed in DNA ploidy status. The K-M analyses showed no significant differences between both entities in relation to DFS or OS.

CONCLUSION

Apart from multifocality, familial PTC appears to have similar clinical/prognostic behaviour when compared with sporadic forms of the disease.

Controversies in familial thyroid cancer 2014

Thyroid cancer is the sixth most common cancer in women, and the majority of patients with thyroid cancer has sporadic disease. However, about 25% of patients with medullary thyroid cancer and 5% with papillary thyroid cancer have familial tumors. Currently, there are numerous controversies regarding the mode of inheritance, tumor behavior, extent of surgical resection for optimal results, coexisting thyroid pathology, risk of other cancers, and extent of postoperative treatment of patients with familial thyroid cancer. This review aimed to give insight to surgeons on this interesting topic.

Cumulative risk impact of five genetic variants associated with papillary thyroid carcinoma

BACKGROUND

Two recent genome-wide association studies (GWASs) identified five single nucleotide polymorphisms (SNPs; rs965513, rs944289, rs966423, rs2439302, and rs116909374) associated with papillary thyroid carcinoma (PTC). Each variant showed highly significant but moderate to low disease risk. Here we assessed the cumulative risk and predictive value of the five SNPs.

METHODS

We genotyped two cohorts of individuals, 747 PTC cases and 1047 controls from Ohio and 1795 PTC cases and 2090 controls from Poland. Cumulative genetic risk scores were calculated using unweighted and weighted approaches.

RESULTS

All five SNPs showed significant association with PTC. The average cumulative risk score in cases was significantly higher than in controls (p<2.2×10(-16)). Each additional risk allele increased the risk of having PTC by 1.51 [95% confidence interval (CI) 1.4, 1.64] in Ohio and by 1.35 [95% CI 1.27, 1.44] in Poland. An analysis was performed weighing risk alleles by effect size and assigning individuals to three weighted risk score groups, low (≤2), medium (2-5), and high (>5). Individuals in the high group were significantly more susceptible to PTC compared with individuals in the low group with an odds ratio of 8.7 [95% CI 5.8, 13.3] in Ohio and 4.24 [95% CI 3.10, 5.84] in Poland. Almost identical results were obtained when follicular variant PTCs and microPTCs were omitted. These five SNPs explained 11% of the familial risk of thyroid cancer in the Ohio cohort and 6% in the Polish cohort.

CONCLUSION

As the genetic risk score increases, the risk of having PTC increases. However, the predictive power of the cumulative effect of these five variants is only moderately high and clinical use may not be feasible until more variants are detected.

Familial nonmedullary thyroid carcinoma

BACKGROUND

Nonmedullary thyroid cancers (NMTC) originate from the follicular cells of the thyroid gland and account for over 90% of all thyroid cancers. About 3-10% of the NMTCs are of familial origin, and familial NMTC (FNMTC) is defined as two or more affected first-degree relatives with NMTC in the absence of other known familial syndromes.

SUMMARY

The genes involved in the pathogenesis of FNMTC are yet to be elucidated, although some recent studies identified several predisposition loci with a high degree of genetic heterogeneity. To date, several studies have evaluated the aggressive tumor characteristics associated with FNMTC with conflicting results. Several studies demonstrated that patients with FNMTC have increased rates of multifocal disease, extrathyroidal invasion, and involved lymph nodes compared with sporadic disease. It has been hypothesized that this increased aggressiveness translates into higher recurrence rates and decreased survival of patients with FNMTC.

CONCLUSION

This review highlights clinical aspects and management dilemmas as well as controversial issues in FNMTC. Management recommendations are deduced.

Ultra-rare mutation in long-range enhancer predisposes to thyroid carcinoma with high penetrance

Thyroid cancer shows high heritability but causative genes remain largely unknown. According to a common hypothesis the genetic predisposition to thyroid cancer is highly heterogeneous; being in part due to many different rare alleles. Here we used linkage analysis and targeted deep sequencing to detect a novel single-nucleotide mutation in chromosome 4q32 (4q32A>C) in a large pedigree displaying non-medullary thyroid carcinoma (NMTC). This mutation is generally ultra-rare; it was not found in 38 NMTC families, in 2676 sporadic NMTC cases or 2470 controls. The mutation is located in a long-range enhancer element whose ability to bind the transcription factors POU2F and YY1 is significantly impaired, with decreased activity in the presence of the C- allele compared with the wild type A-allele. An enhancer RNA (eRNA) is transcribed in thyroid tissue from this region and is greatly downregulated in NMTC tumors. We suggest that this is an example of an ultra-rare mutation predisposing to thyroid cancer with high penetrance.

SRGAP1 is a candidate gene for papillary thyroid carcinoma susceptibility

BACKGROUND

Papillary thyroid carcinoma (PTC) shows high heritability, yet efforts to find predisposing genes have been largely negative.

OBJECTIVES

The objective of this study was to identify susceptibility genes for PTC.

METHODS

A genome-wide linkage analysis was performed in 38 families. Targeted association study and screening were performed in 2 large cohorts of PTC patients and controls. Candidate DNA variants were tested in functional studies.

RESULTS

Linkage analysis and association studies identified the Slit-Robo Rho GTPase activating protein 1 gene (SRGAP1) in the linkage peak as a candidate gene. Two missense variants, Q149H and A275T, localized in the Fes/CIP4 homology domain segregated with the disease in 1 family each. One missense variant, R617C, located in the RhoGAP domain occurred in 1 family. Biochemical assays demonstrated that the ability to inactivate CDC42, a key function of SRGAP1, was severely impaired by the Q149H and R617C variants.

CONCLUSIONS

Our findings suggest that SRGAP1 is a candidate gene in PTC susceptibility. SRGAP1 is likely a low-penetrant gene, possibly of a modifier type.

FOXE1 polymorphisms are associated with familial and sporadic nonmedullary thyroid cancer susceptibility

OBJECTIVE

FOXE1 is a transcription factor required for thyroid differentiation and function. FOXE1 locus polymorphisms (chromosome 9q22.33) were recently associated with increased sporadic thyroid cancer risk. In this study, we aimed to investigate the association of FOXE1 variants with nonmedullary thyroid cancer (NMTC), in both sporadic and familial (FNMTC) cases from the Portuguese population.

DESIGN AND METHODS

Nine variants located at the FOXE1 locus were sequenced in genomic DNA from 60 FNMTC probands and 80 patients with sporadic NMTC. Alleles were tested for association with thyroid cancer, against 130 healthy matched Portuguese controls.

RESULTS

All variants were significantly associated with increased thyroid cancer risk when combining familial and sporadic cases (OR range = 1·62-2·58). In particular, two reported risk variants were associated with the disease: rs965513 (allele A) with familial (OR = 2·30, 95% CI = 1·48-3·59, P = 0·0002) and sporadic (OR = 2·81, 95% CI = 1·87-4·22, P < 0·0001) NMTC and rs1867277 (allele A) with the sporadic (OR = 1·76, 95% CI = 1·18-2·62, P = 0·0052) and combined NMTC cases (OR = 1·70, 95% CI = 1·21-2·40, P = 0·0022). Interestingly, we also identified association of FOXE1 polyalanine tract expansions (>14 alanines) with thyroid cancer risk, in both familial (OR = 2·56, 95% CI = 1·64-4·01, P < 0·0001) and sporadic (OR = 2·44, 95% CI = 1·61-3·68, P < 0·0001) cases.

CONCLUSIONS

We found compelling evidence of association between FOXE1 variants and thyroid cancer risk in the Portuguese population. To our knowledge, this is the first study supporting the association of this locus with both sporadic and familial NMTC susceptibility.

The biology and the genetics of Hurthle cell tumors of the thyroid

The biology and the genetics of Hürthle cell tumors are reviewed starting from the characterization and differential diagnosis of the numerous benign and malignant, neoplastic and nonneoplastic lesions of the thyroid in which Hürthle cell transformation is frequently observed. The clinicopathologic and molecular evidence obtained from the comparative study of the aforementioned conditions indicate that Hürthle cell appearance represents a phenotype that is superimposed on the genotypic and conventional histopathologic features of the tumors. Hürthle cell tumors differ from their non-Hürthle counterparts regarding the prevalence of large deletions of mitochondrial DNA (mtDNA), mutations of mtDNA genes coding for oxidative phosphorylation (OXPHOS) proteins (namely mutations of complex I subunit genes) and mutations of nuclear genes coding also for mitochondrial OXPHOS proteins. Such mitochondrial alterations lead to energy production defects in Hürthle cell tumors; the increased proliferation of mitochondria may reflect a compensatory mechanism for such defects and is associated with the overexpression of factors involved in mitochondrial biogenesis. The mitochondrial abnormalities are also thought to play a major role in the predisposition for necrosis instead of apoptosis which seems to be blocked in most Hürthle cell tumors. Finally, the results obtained in experimental models using cybrid cell lines and the data obtained from histopathologic and molecular studies of familial Hürthle cell tumors are used, together with the aforementioned genetic and epigenetic alterations, to progress in the understanding of the mechanisms through which mitochondrial abnormalities may be involved in the different steps of thyroid carcinogenesis, from tumor initiation to metastization.

MiR-886-3p regulates cell proliferation and migration, and is dysregulated in familial non-medullary thyroid cancer

Background

The molecular basis and characteristics of familial non-medullary thyroid cancer are poorly understood. In this study, we performed microRNA (miRNA) profiling of familial and sporadic papillary thyroid cancer tumor samples.

Methodology/Principal Findings

Genome wide miRNA profiling of sporadic and familial papillary thyroid cancer was performed. Differentially expressed miRNAs were validated by quantitative RT-PCR. Ectopic expression of miR-886-3p in thyroid cancer lines was performed to identify pathways targeted by the miRNA, as well as, to determine its effect on tumor cell biology. We found four differentially expressed miRNAs between familial and sporadic papillary thyroid cancer tumor samples. MiR-886-3p and miR-20a were validated to be differentially expressed by 3- and 4-fold, respectively. Pathway analysis of genome-wide expression data on cells overexpressing miR-886-3p and target prediction analysis showed genes involved in DNA replication and focal adhesion pathways were regulated by miR-886-3p. Overexpression of miR-886-3p in thyroid cancer cell lines significantly inhibited cellular proliferation, the number and size of spheroids and cellular migration. Additionally, overexpression of miR-886-3p increased the number of cells in S phase.

Conclusions/Significance

Our findings for the first time suggest that miR-886-3p plays an important role in thyroid cancer tumor cell biology and regulates genes involved in DNA replication and focal adhesion. Thus, miR-886-3p may play a role in the initiation and or progression of papillary thyroid cancer.

Association studies in thyroid cancer susceptibility: are we on the right track?

It is widely accepted that thyroid cancer is strongly determined by the individual genetic background. In this regard, it is expected that sporadic thyroid cancer is the result of multiple low- to moderate-penetrance genes interacting with each other and with the environment, thus modulating individual susceptibility. In the last years, an important number of association studies on thyroid cancer have been published, trying to determine this genetic contribution. The aim of this review is to provide a comprehensive and critical evaluation of the associations reported so far in thyroid cancer susceptibility in case-control studies performed in both non-medullary (papillary and follicular) and medullary thyroid cancers, including their potential strengths and pitfalls. We summarize the genetic variants reported to date, and stress the importance of validating the results in independent series and assessing the functional role of the associated loci.

Chromosomal, epigenetic and microRNA-mediated inactivation of LRP1B, a modulator of the extracellular environment of thyroid cancer cells

The low-density lipoprotein receptor-related protein (LRP1B), encoding an endocytic LDL-family receptor, is among the 10 most significantly deleted genes across 3312 human cancer specimens. However, currently the apparently crucial role of this lipoprotein receptor in carcinogenesis is not clear. Here we show that LRP1B inactivation (by chromosomal, epigenetic and microRNA (miR)-mediated mechanisms) results in changes to the tumor environment that confer cancer cells an increased growth and invasive capacity. LRP1B displays frequent DNA copy number loss and CpG island methylation, resulting in mRNA underexpression. By using CpG island reporters methylated in vitro, we found that DNA methylation disrupts a functional binding site for the histone-acetyltransferase p300 located at intron 1. We identified and validated an miR targeting LRP1B (miR-548a-5p), which is overexpressed in cancer cell lines as a result of 8q22 DNA gains. Restoration of LRP1B impaired in vitro and in vivo tumor growth, inhibited cell invasion and led to a reduction of matrix metalloproteinase 2 in the extracellular medium. We emphasized the role of an endocytic receptor acting as a tumor suppressor by modulating the extracellular environment composition in a way that constrains the invasive behavior of the cancer cells.

Familial thyroid neoplasia: impact of technological advances on detection and monitoring

PURPOSE OF REVIEW

To weigh the clinical impact of new technological insights into heritable thyroid malignancies.

RECENT FINDINGS

Medullary thyroid carcinoma and familial nonmedullary thyroid cancers represent the small minority of thyroid cancers that are inherited. New insights into the genetic alterations and molecular mechanisms implicated in these tumors are serving to refine the clinical tools available for their initial diagnosis as well as subsequent follow-up. In addition to an analysis of rearranged during transfection mutations and calcitonin profiles in medullary thyroid carcinoma, this review includes emphasis on familial nonmedullary thyroid cancer syndromes, including genetic findings in familial papillary thyroid cancer, familial adenomatous polyposis, Cowden syndrome, Carney complex, and Werner syndrome.

SUMMARY

Genetic mutational information is increasingly available on medullary and familial nonmedullary thyroid cancer and their associated syndromes. The clinical significance of this information for affected patients and their families continues to undergo evaluation.

'Chromosomal Rainbows' Detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors

Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as 'TRKA'), RET ('Rearranged during Transfection protooncogene', OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3'- end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners.We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabasepair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC's). While rendering accurate information about the cytogenetic location of rearranged elements, our multi-locus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding techniques for fine mapping of breakpoints in papillary thyroid cancer (PTC).

Review Article: The Familial Counterparts of Follicular Cell—Derived Thyroid Tumors

The follicular cell—derived thyroid cancers (termed nonmedullary thyroid cancers—NMTCs) occur mostly sporadically, but intriguingly, NMTC has the highest familial risk among all cancer sites. This epidemiological observation is strengthened by the clinical occurrence of NMTC in familial aggregation (FNMTC) and by the detection of chromosomal loci in linkage with the disease phenotype. FNMTC loci have been proposed at 14q, 1q21, 19p13.2, 2q21, 8p23, 8q24, 1q21, and 6q22, but to date, no causative mutations have been linked to FNMTCs. In this review, the authors focus on the clinical, morphological, and molecular aspects that characterize familial tumors. Some morphological patterns may alert for a familial disease. FNMTCs share several of the somatic molecular changes associated with sporadic tumors. New genes affected by somatic changes have been disclosed within regions harboring FNMTC loci.