Familial non-medullary thyroid cancer: a critical review

Novel truncating germline variant reinforces TINF2 as a susceptibility gene for familial non-medullary thyroid cancer

BACKGROUND

It has long been observed that there are families in which non-medullary thyroid cancer (NMTC) occurs, but few syndromes and genes have been described to date. Proteins in the shelterin complex have been implied in cancer. Here, we have studied shelterin genes in families affected by NMTC (FNMTC).

METHODS

We performed whole-exome sequencing (WES) in 10 affected individuals from four families with at least three affected members. Polymerase chain reaction (PCR) and Sanger sequencing were performed to search for variants in the TINF2 gene in 40 FNMTC families. TINF2 transcripts and loss of heterozygosity (LOH) were studied in several affected patients of one family.

RESULTS

We found the c.507G>T variant in heterozygosis in the TINF2 gene in one family, co-segregating in all five affected members. This variant affects the normal splicing. LOH was not observed.

CONCLUSIONS

Our results reinforce the TINF2 gene as a susceptibility cause of FNMTC suggesting the importance of location of frameshift variants in TINF2. According to our data and previous literature, TINF2 pathogenic variants appear to be a significant risk factor for the development of NMTC and/or melanoma.

Progression of Nodular Thyroid Disease in Familial Adenomatous Polyposis Syndrome: Refined Surveillance Recommendations

BACKGROUND

Patients with familial adenomatous polyposis (FAP) have an increased risk of thyroid nodular disease. Previous studies demonstrated that screening thyroid ultrasound (US) will allow detection of nodules in 38% and thyroid cancer in 2.6% of patients. The aim of this study is to define the value of serial US evaluation at identifying disease progression in patients with FAP.

METHODS

Retrospective review from 2008 to 2023 at a single referral center. All patients with FAP and screening thyroid US were included. Patient demographics, initial US characteristics, follow-up regarding the development of new nodules and cancer were assessed using a Kaplan-Meier analysis.

RESULTS

A total of 556 patients underwent screening. Fifty percent were male. Median age at first screening was 38 year old. Eighty percent underwent longitudinal follow-up for a median length of 7 years. At initial screening, 169 patients (30%) had nodules. For patients with normal baseline US, 14% developed a nodule overtime. A total of 20 patients (3.6%) were diagnosed with thyroid cancer. The cumulative incidence of initial and subsequent cancer was 4% by 5 years and 6% by 10 years, while the cumulative incidence of thyroid nodules was 40% and 48%, respectively.

CONCLUSIONS

Based on the Kaplan-Meier analysis, ongoing longitudinal screening is warranted for patients with FAP as they are prone to thyroid cancer and nodule development overtime even when presenting with a baseline normal US. Additionally, these data demonstrate a slow development of thyroid cancer from a normal US, thus it is reasonable to consider selectively extending the screening interval for this population.

Telomere-lengthening germline variants predispose to a syndromic papillary thyroid cancer subtype

Papillary thyroid cancer (PTC) is the most common endocrine malignancy. 10% to 15% of individuals show familial clustering with three or more affected members, but the factors underlying this risk are unknown. In a group of recently studied individuals with POT1 pathogenic variants and ultra-long telomere length, PTC was the second most common solid tumor. We tested whether variants in POT1 and four other telomere-maintenance genes associated with familial cancer underlie PTC susceptibility. Among 470 individuals, we identified pathogenic or likely pathogenic variants in three genes encoding telomere-binding proteins: POT1, TINF2, and ACD. They were found in 4.5% and 1.5% of familial and unselected cases, respectively. Individuals harboring these variants had ultra-long telomere length, and 15 of 18 (83%) developed other cancers, of which melanoma, lymphoma, and sarcoma were most common. Among individuals with PTC and melanoma, 22% carried a deleterious germline variant, suggesting that a long telomere syndrome might be clinically recognizable. Successive generations had longer telomere length than their parents and, at times, developed more cancers at younger ages. Tumor sequencing identified a single oncogenic driver, BRAF p.Val600Glu, in 10 of 10 tumors studied, but no telomere-maintenance mechanism, including at the TERT promoter. These data identify a syndromic subset of PTCs with locus heterogeneity and telomere lengthening as a convergent mechanism. They suggest these germline variants lower the threshold to cancer by obviating the need for an acquired telomere-maintenance mechanism in addition to sustaining the longevity of oncogenic mutations.

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.

Clinical relevance and outcome of familial papillary thyroid cancer: a single institution study of 626 familial cases

Background

Whether familial thyroid cancer is more aggressive than sporadic thyroid cancer remains controversial. Additionally, whether the number of affected family members affects the prognosis is unknown. This study focused mainly on the comparison of the clinicopathological characteristics and prognoses between papillary thyroid cancer (PTC) patients with and without family history.

Methods

A total of 626 familial papillary thyroid cancer (FPTC) and 1252 sporadic papillary thyroid cancer (SPTC) patients were included in our study. The clinical information associated with FPTC and SPTC was recorded and analyzed by univariate analysis.

Results

Patients in the FPTC group had a higher rate of multifocality (p=0.001), bilaterality (p=0.000), extrathyroidal invasion (p=0.000), distant metastasis (p=0.012), lymph node metastasis (p=0.000), recurrence (p=0.000), a larger tumor size (p=0.000) and more malignant lymph nodes involved (central: p=0.000; lateral: p=0.000). In addition, our subgroup analysis showed no significant difference (p>0.05) between patients with only one affected family member and those with two of more group in all clinicopathological characteristics. In papillary thyroid microcarcinoma (PTMC) subgroup analysis, we found that FPTMC patients harbored significantly larger tumors (p=0.000), higher rates of multifocality (p=0.014), bilaterality (p=0.000), distant metastasis (p=0.038), lymph node metastasis (p=0.003), greater numbers of malignant lymph nodes (central: p=0.002; lateral: p=0.044), higher rates of I-131 treatment (p=0.000) and recurrence (p=0.000) than SPTMC patients.

Conclusion

Our results indicated that PTC and PTMC patients with a positive family history had more aggressive clinicopathological behaviors, suggesting that more vigilant screening and management for FPTC may be helpful.

FAMILIAL NON-MEDULLARY THYROID CARCINOMA

BACKGROUND

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.

AIM

To analyze clinical manifestations of FNMTC and compare them with the data for sporadic papillary thyroid carcinomas in patients of the same age groups.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

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.

Identification of Novel Candidate Genes for Familial Thyroid Cancer by Whole Exome Sequencing

Thyroid carcinoma (TC) can be classified as medullary (MTC) and non-medullary (NMTC). While most TCs are sporadic, familial forms of MTC and NMTC also exist (less than 1% and 3-9% of all TC cases, respectively). Germline mutations in RET are found in more than 95% of familial MTC, whereas familial NMTC shows a high degree of genetic heterogeneity. Herein, we aimed to identify susceptibility genes for familial NMTC and non-RET MTC by whole exome sequencing in 58 individuals belonging to 18 Spanish families with these carcinomas. After data analysis, 53 rare candidate segregating variants were identified in 12 of the families, 7 of them located in previously TC-associated genes. Although no common mutated genes were detected, biological processes regulating functions such as cell proliferation, differentiation, survival and adhesion were enriched. The reported functions of the identified genes together with pathogenicity and structural predictions, reinforced the candidacy of 36 of them, suggesting new loci related to TC and novel genotype-phenotype correlations. Therefore, our strategy provides clues to possible molecular mechanisms underlying familial forms of MTC and NMTC. These new molecular findings and clinical data of patients may be helpful for the early detection, development of tailored therapies and optimizing patient management.

MEN1 in a Patient With Nonsyndromic Familial Nonmedullary Thyroid Carcinoma

Clinical syndromes involving multiple endocrine glands have been well recognized for over a century. Multiple reports describing hereditary multiple endocrine neoplasia (MEN) syndromes involving pituitary, parathyroid, and pancreatic neuroendocrine tumors have been published. Differentiated (nonmedullary) thyroid cancer can also present as a hereditary syndrome with or without a specific genetic predisposition. We report the case of a man with nonsyndromic familial nonmedullary thyroid carcinoma, a pituitary adenoma, hyperparathyroidism, an adrenal adenoma, and pancreatic adenocarcinoma. Genetic testing did not reveal mutations in the commonly reported genes associated with MEN syndromes. MEN1 is characterized by endocrine neoplasia in at least 2 of the following glands: pituitary, parathyroid, and the gastro-entero-pancreatic (GEP) tract. Co-occurrence of MEN1 with familial nonmedullary thyroid carcinoma, however, has not been reported in the medical literature. This unique case of MEN1 co-existing in a patient with nonsyndromic familial thyroid carcinoma was not associated with any common MEN syndrome germline mutations.

Molecular Landscape of Pediatric Thyroid Cancer: A Review

Thyroid carcinomas (TC) are rare in the pediatric population; however, they constitute the most common endocrine malignancy. Despite some similarities with adult carcinomas, they have distinct clinical behavior and responses to therapy due to their unique pathology and molecular characteristics. The age cut-off used for defining the pediatric age group has been variable across different studies, and the universally accepted recommendations influence accurate interpretation of the available data. Moreover, factors such as radiation exposure and germline mutations have greater impact in children than in adults. Papillary TC is the most common and the most evaluated pediatric TC. Others, including follicular, poorly differentiated and medullary carcinomas, are rarer and have limited available literature. Most studies are from the West. Asian studies are primarily from Japan, with few from China, India, Saudi Arabia and Republic of Korea. This review provides a comprehensive account of the well-established and novel biomarkers in the field, including point mutations, fusions, miRNA, and thyroid differentiation genes. Familial and syndromic associations are also discussed. Current management guidelines for pediatric patients are largely derived from those for adults. An awareness of the molecular landscape is essential to acknowledge the uniqueness of these tumors and establish specific diagnostic and therapeutic guidelines.

Papillary Thyroid Carcinoma: Current Position in Epidemiology, Genomics, and Classification

Papillary thyroid carcinoma is the most common type of thyroid malignancy both in adults and pediatric population. Since the 1980s, there are changes in criteria in labelling thyroid lesions as "papillary thyroid carcinomas." Radiation exposure is a well-established risk factor for papillary thyroid carcinoma. Other environmental risk factors include dietary iodine, obesity, hormones, and environmental pollutants. Papillary thyroid carcinomas could occur in familial settings, and 5% of these familial cases have well-studied driver germline mutations. In sporadic papillary thyroid carcinoma, BRAF mutation is common and is associated with clinicopathologic and prognostic markers. The mutation could aid in the clinical diagnosis of papillary thyroid carcinoma. Globally, thyroid cancer is among the top ten commonest cancer in females. In both adult and pediatric populations, there are variations of prevalence of thyroid cancer and rising incidence rates of thyroid cancer worldwide. The increase of thyroid cancer incidence was almost entirely due to the increase of papillary thyroid carcinoma. The reasons behind the increase are complex, multifactorial, and incompletely understood. The most obvious reasons are increased use of diagnostic entities, change in classification of thyroid neoplasms, as well as factors such as obesity, environmental risk factors, and radiation. The prognosis of the patients with papillary thyroid carcinoma is generally good after treatment. Nevertheless, cancer recurrence and comorbidity of second primary cancer may occur, and it is important to have awareness of the clinical, pathological, and molecular parameters of papillary thyroid carcinoma.

Clinical characteristics and prognosis of familial nonmedullary thyroid carcinoma

INTRODUCTION

Familial 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 METHODS

Retrospective study of DTC included in the hospital database during the period 1990-2018.

RESULTS

A 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).

CONCLUSION

In our study FNMTC presents a lower TNM staging, higher multifocality and papillary variant, with similar aggressiveness and prognosis compared to SC.

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.

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.

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

INTRODUCTION

Survival 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.

PURPOSE

To assess the risk of SMN in a large cohort of sporadic and familial NMTC using the standardized incidence ratio (SIR).

PATIENTS AND METHODS

We 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).

RESULTS

We 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).

CONCLUSIONS

NMTC 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.

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.

Papillary Thyroid Cancer Affecting Multiple Family Members: A Case Report and Literature Review of Familial Nonmedullary Thyroid Cancer

Familial nonmedullary thyroid cancer (FNMTC) represents 5–10% of NMTC cases. Many controversies are associated with the FNMTC, namely, the minimum required number of affected family members to define the condition, aggressiveness, prognosis, and treatment and screening recommendations. Moreover, the genetic basis of the FNMTC has not yet been identified. We report a family diagnosed with FNMTC and present a comprehensive literature review of the condition. The index case was a 26-year-old male who was diagnosed with locally advanced papillary thyroid cancer (PTC). Then, his family members became worried and asked for a neck ultrasound. Four of his six siblings, in addition to his father, were diagnosed with PTC. In addition, two of his cousins were diagnosed. The patient underwent total thyroidectomy with bilateral neck dissection, and he received 2 doses of radioactive iodine (100 mCi each). Furthermore, one of his siblings required a second surgery with repeated radioactive iodine therapy. The index case genetic screening and whole-exome sequencing did not show any abnormalities. Future genetic and clinical research should focus on kindred with 3 or more affected individuals for better identification of the FNMTC susceptibility genes and to better guide management and screening recommendations.

Clinical characteristics and prognosis of familial nonmedullary thyroid carcinoma

INTRODUCTION

Familial non-medullary thyroid carcinoma (FNMTC) is defined by the presence of 2or 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 METHODS

Retrospective study of DTC included in the hospital database during the period 1990-2018.

RESULTS

A 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=.003) consequence of a higher proportion of tumors smaller than 2 centimeters (P=.003), combined with a greater multifocality (P=.034) and papillary histologic subtype (P=.022) compared to SC. No significant differences in age at diagnosis (P=.347), gender (P=.406), neither in other aggressiveness markers (bilaterality, extrathyroidal extension, lymph node involvement and metástasis) were detected. Rate of persistence/recurrence (P=.656), disease-free survival (P=.929) and mortality caused by the tumor itself (P=.666) were comparable. Families with ≥3 affected relatives, had smaller tumors (P=.005), more multifocality (P=.040) and bilaterality (P=.002), as well as a higher proportion of males (P=.020). Second generation patients present earlier FNMTC compared to those of the first generation (P=.001).

CONCLUSION

In our study FNMTC presents a lower TNM staging, higher multifocality and papillary variant, with similar aggressiveness and prognosis compared to SC.

Genetics of Familial Non-Medullary Thyroid Carcinoma (FNMTC)

Non-medullary thyroid carcinoma (NMTC) is the most frequent endocrine tumor and originates from the follicular epithelial cells of the thyroid. Familial NMTC (FNMTC) has been defined in pedigrees where two or more first-degree relatives of the patient present the disease in absence of other predisposing environmental factors. Compared to sporadic cases, FNMTCs are often multifocal, recurring more frequently and showing an early age at onset with a worse outcome. FNMTC cases show a high degree of genetic heterogeneity, thus impairing the identification of the underlying molecular causes. Over the last two decades, many efforts in identifying the susceptibility genes in large pedigrees were carried out using linkage-based approaches and genome-wide association studies, leading to the identification of susceptibility loci and variants associated with NMTC risk. The introduction of next-generation sequencing technologies has greatly contributed to the elucidation of FNMTC predisposition, leading to the identification of novel candidate variants, shortening the time and cost of gene tests. In this review we report the most significant genes identified for the FNMTC predisposition. Integrating these new molecular findings in the clinical data of patients is fundamental for an early detection and the development of tailored therapies, in order to optimize patient management.

Longer Time to Reach Excellent Response to Treatment in Familial Versus Sporadic Non-medullary Thyroid Cancer (NMTC): A Matched Case-Control Study

BACKGROUND

Familial non-medullary thyroid cancer (NMTC) are supposed to be more aggressive and require more frequent treatment compared to non-familial thyroid cancer.

OBJECTIVES

This matched case-control study aimed to compare the response to treatment between the matched case-control groups of familial and sporadic NMTC.

METHODS

This is a retrospective study in patients with familial NMTC (at least one other first-degree relative involved) who were treated with surgery, followed by radio-iodine therapy (RIT) without consideration of its familial origin. Response to treatment was compared between familial NMTC and age, sex, and TNM stage-matched non-familial NMTC (control group). Response to treatment was assessed one and two years after RIT, and time to excellent response was identified.

RESULTS

Out of 2,944 NMTC patients, 81 (2.75%) patients had familial NMTC. We compared 66 patients with familial NMTC and 66 sporadic NMTC patients. There was no significant difference in first thyroglobulin, initial and accumulative iodine dose, and additional treatments (additional surgery and radiotherapy) between patients and controls. Although no significant difference was noted in one and two years' responses to treatment between the case and control groups, familial NMTC patients required more time to achieve excellent response (26.7 ± 24.9 versus 15.9 ± 9.0 months, P = 0.01). No significant difference was noted between familial NMTC patients with two or more than two involved relatives.

CONCLUSIONS

Our study showed that if patients with familial NMTCs were treated in the same way as non-familial patients, the time to excellent response would be significantly longer, even when they have only one other involved relative.

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.