Genotype and phenotype of patients with both familial adenomatous polyposis and thyroid carcinoma

De novo familial adenomatous polyposis associated thyroid cancer with a c.2929delG frameshift deletion mutation in APC: a case report and literature review

BACKGROUND

Germline mutations in the APC gene located on chromosome 5q 21-22 can lead to familial adenomatous polyposis (FAP) and the development of colorectal cancer (CRC) if left untreated. As a rare extracolonic manifestation, thyroid cancer is diagnosed in about 2.6% of FAP patients. The genotype-phenotype correlation in FAP patients with thyroid cancer remains unclear.

CASE PRESENTATION

We present a 20-year-old female of FAP with thyroid cancer as the initial manifestation. The patient was asymptomatic and developed colon cancer liver metastases 2 years after the diagnosis of thyroid cancer. The patient underwent multiple surgical treatments in several organs, and regular colonoscopy with endoscopic polypectomy was performed. Genetic testing demonstrated the c.2929delG (p.Gly977Valfs*3) variant in exon 15 of the APC gene. This represents a previously undescribed APC mutation. This mutation causes loss of multiple structures on the APC gene including the 20-amino acid repeats, the EB1 binding domain, and the HDLG binding site, which may be pathogenic through β-catenin accumulation, cell cycle microtubule dysregulation, and tumor suppressor inactivation.

CONCLUSIONS

We report a de novo FAP case with thyroid cancer presenting atypically aggressive features harboring a novel APC mutation and review APC germline mutations in patients with FAP-associated thyroid cancer.

Looking at Thyroid Cancer from the Tumor-Suppressor Genes Point of View

Simple Summary

Thyroid cancer is the most common endocrine cancer. As tumor-suppressor genes (TSGs) are implicated in many different functions in the organism, their loss in cells in a normal tissue may drive their transformation into cancer cells. TSGs are generally classified into three subclasses: (i) gatekeepers that encode proteins involved in the control of cell cycle and apoptosis; (ii) caretakers that produce proteins implicated in maintaining genomic stability; and (iii) landscapers that, when mutated, create a suitable environment for neoplastic growth. Different inactivation mechanisms may suppress TSG function. Understanding these mechanisms and TSG alterations in thyroid tumors is of great importance for thyroid cancer prognosis, diagnosis, and therapy. The present review paper discusses TSG inactivation mechanisms and alterations in order to help to identify more efficient therapeutic modalities for thyroid cancer management.

Abstract

Thyroid cancer is the most frequent endocrine malignancy and accounts for approximately 1% of all diagnosed cancers. A variety of mechanisms are involved in the transformation of a normal tissue into a malignant one. Loss of tumor-suppressor gene (TSG) function is one of these mechanisms. The normal functions of TSGs include cell proliferation and differentiation control, genomic integrity maintenance, DNA damage repair, and signaling pathway regulation. TSGs are generally classified into three subclasses: (i) gatekeepers that encode proteins involved in cell cycle and apoptosis control; (ii) caretakers that produce proteins implicated in the genomic stability maintenance; and (iii) landscapers that, when mutated, create a suitable environment for malignant cell growth. Several possible mechanisms have been implicated in TSG inactivation. Reviewing the various TSG alteration types detected in thyroid cancers may help researchers to better understand the TSG defects implicated in the development/progression of this cancer type and to find potential targets for prognostic, predictive, diagnostic, and therapeutic purposes. Hence, the main purposes of this review article are to describe the various TSG inactivation mechanisms and alterations in human thyroid cancer, and the current therapeutic options for targeting TSGs in thyroid cancer.

Novel Mutation in APC Gene Associated with Multiple Osteomas in a Family and Review of Genotype-Phenotype Correlations of Extracolonic Manifestations in Gardner Syndrome

Gardner syndrome is a neoplasic disease that associates intestinal polyposis and colorectal adenocarcinoma with osteomas and soft tissue tumors determined by germline mutations in the APC gene. The early diagnosis and identification of high-risk individuals are important because patients have a 100% risk of colon cancer. We present the case of a family with Gardner syndrome. Cephalometric, panoramic X-rays and CBCT of the proband and her brother showed multiple osteomas affecting the skull bones, mandible and paranasal sinuses. The detailed family history showed an autosomal dominant transmission with the presence of the disease in the mother and maternal grandfather of the proband. Both had the typical signs of disease and died in the fourth decade of life. Based on these aspects the clinical diagnosis was Gardner syndrome. By gene sequencing, a novel pathogenic variant c.4609dup (p.Thr1537Asnfs*7) in heterozygous status was identified in the APC gene in both siblings. We reviewed literature data concerning the correlation between the localization of mutations in the APC gene and the extracolonic manifestations of familial adenomatous polyposis as well as their importance in early diagnosis and adequate oncological survey of patients and families based on abnormal genomic variants.

Cribiform-morular variant of papillary thyroid carcinoma and familial adenomatous polyposis: Report of a case

Cribiform-morular thyroid carcinoma is a rare variant of papillary thyroid carcinoma. It is usually related to Familial Adenomatous Polyposis (FAP) but rarely it may be sporadic. This variant of PTC occurs in young females and it is rare in the elderly. We report a case of a 20 years old female presenting thyroid carcinoma and personal history of FAP.

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.

Outcome of thyroid ultrasound screening in FAP patients with a normal baseline exam

Familial adenomatous polyposis (FAP) is a hereditary cancer syndrome associated with a substantial lifetime risk for colorectal cancer. The leading extra-colonic causes of cancer in FAP include duodenal and thyroid cancer (TC). Recent guidelines recommend annual thyroid ultrasound (TUS) screening beginning in the teenage years but the evidence to support the interval particularly in FAP patients with a normal baseline ultrasound is lacking. TUS results from FAP patients enrolled in a thyroid screening program from 2006 to 2016 and who had at least 2 TUS were reviewed. TUS findings were classified as normal, low (LR) or high risk (HR) for TC based on nodule characteristics as determined by American Thyroid Association (ATA) guidelines. We assessed the incidence of TC in patient with normal baseline TUS and factors associated with TC. 264 FAP patients were included. Baseline TUS was normal in 167, LR in 74, and HR in 24 patients. Patients were observed for a mean 4.8 years and underwent an average of 3 TUS. Patients with normal baseline TUS did not develop TC during the course of follow up of 5.1 years. TC developed in 6 patients (2.3%) all with baseline nodules; 5 in the LR group and 1 in the HR group. Factors associated with development of TC were presence of baseline nodule(s) and female sex. The development of TC in FAP patients in a TUS screening program with short term follow up is low and no FAP patient with a normal baseline TUS developed TC during observation. Annual TUS in patients with a normal baseline TUS may not be needed. Extending the screening interval to 2 years may be reasonable until nodules are detected.

Barriers to thyroid cancer screening with ultrasound in patients with familial adenomatous polyposis

OBJECTIVES/HYPOTHESIS

To identify barriers to care in patients with familial adenomatous polyposis (FAP) that have not undergone ultrasound for thyroid cancer (TC) screening.

STUDY DESIGN

Case series and survey.

METHODS

A study was conducted examining referral patterns for thyroid ultrasound (TUS) in FAP patients for TC screening. Patients with FAP seen at our institution were identified using International Classification of Diseases, Ninth Revision and Tenth Revision codes. Chart review was performed for TUS and the results were recorded. Patients and healthcare providers were surveyed to determine barriers to TUS and opportunities for improvement.

RESULTS

Thirteen out of 35 patients surveyed (37%) were told by a healthcare provider that TUS was recommended for TC screening. The incidence for TC in FAP patients ranges from 15 to 12%, whereas the general population risk is 0.02% to 1%. In our series, one patient of 12 (8%) had TC. Barriers to care included poor patient education about the risk of TC in FAP and miscommunication among specialties for referral for TUS. Also, patients enrolled in a FAP registry have improved care, as they are more likely to undergo TUS than those not enrolled.

CONCLUSIONS

FAP patients are at a higher risk of developing TC. Therefore, it is important for these patients to be informed and follow the recommended guideline to get a baseline TUS for screening as well as receive better patient education about the risk of TC and improved communication among specialties. Additionally, patients enrolled in a FAP registry are more likely to undergo ultrasound for TC screening, so there needs to be more centralized coordination for the multidisciplinary care of this disease.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2436-2441, 2019.

Hereditary Colorectal Cancer Syndromes

OBJECTIVES

To review the most common hereditary colorectal cancer syndromes with known associated mutated genes, associated cancer risks, and current screening and prevention current.

DATA SOURCES

Online search of PubMed, EBSCOhost, and Medline, review of the literature for each syndrome described.

CONCLUSION

Hereditary colon cancer accounts for approximately 10% of all colorectal cancers in the United States. There are multiple hereditary colorectal cancer syndromes known with respective associated genetic mutations, cancer risks, and screening and prevention recommendations.

IMPLICATIONS FOR NURSING PRACTICE

Nurses at all levels of practice need to be knowledgeable about the various hereditary colorectal cancer syndromes to guide appropriate referral to a genetics professional and to provide appropriate care to these high-risk individuals.

Prevalence of and risk factors for thyroid carcinoma in patients with familial adenomatous polyposis: results of a multicenter study in Japan and a systematic review

PURPOSE

To investigate the recent Japanese prevalence of thyroid cancer and its characteristics in familial adenomatous polyposis (FAP) patients, through the development of surveillance programs.

METHODS

The subjects of this study were 282 (93.1%) FAP patients for whom information on thyroid cancer was available, from among 303 patients registered in "the Retrospective Cohort Study of Familial Adenomatous Polyposis in Japan" database. We evaluated the prevalence and risk factors for thyroid cancer and integrated and/or compared our findings with those of previous reports, using a systematic review, including a meta-analysis.

RESULTS

Thyroid cancer was diagnosed in 16 women (11.4%) and 2 men (1.4%), at 17-41 years and 39-57 years of age, respectively. The prevalence of thyroid cancer was 6.4%, with a female-to-male ratio of 8:1, which is comparable to reports from other countries. A young age of < 33 years at the FAP diagnosis and female gender were identified as independent risk factors for thyroid cancer.

CONCLUSIONS

FAP-associated thyroid cancer predominantly affects young women, both in Japan and other countries. Since FAP is generally diagnosed when patients are in their 20 s or older, regular screening for thyroid cancer is recommended for all FAP patients, but especially women, from their early 20 s.

Cribriform-morular variant of thyroid carcinoma: a neoplasm with distinctive phenotype associated with the activation of the WNT/β-catenin pathway

Cribriform-morular variant of thyroid carcinoma is classically associated with familial adenomatous polyposis but, it can also occur as a sporadic neoplasm. This neoplasm is much more frequently observed in women than in men (ratio of 61:1). In familial adenomatous polyposis patients, tumors are generally multifocal and/or bilateral (multinodular appearance), whereas in the sporadic cases tumors tend to occur as single nodules. The tumors are well delimited, and characteristically show a blending of follicular, cribriform, papillary, trabecular, solid, and morular patterns. Neoplastic cells are tall or cuboidal with the occasional nuclear features of classic papillary thyroid carcinoma. The morules include cells with peculiar nuclear clearing and show positivity for CDX2 and CD10. Angioinvasion and capsular invasion have been described in about 30 and 40% of cases, respectively, with lymph node metastases in less than 10% of patients and distant metastases in 6%. Although this tumor has good prognosis, neuroendocrine and/or poor differentiation have been associated with aggressive behavior. Tumor cells can be focally positive or negative for thyroglobulin, but are always positive for TTF-1, estrogen and progesterone receptors, and negative for calcitonin and cytokeratin 20. Nuclear and cytoplasmic staining for β-catenin is the hallmark of this tumor type; this feature plays a role in fine needle aspiration biopsy. Cribriform-morular variant of thyroid carcinoma has a peculiar endodermal (intestinal-like) type phenotype, activation of the WNT/β-catenin signaling pathway, and belongs to the non-BRAF-non-RAS subtype of the molecular classification of thyroid tumors. Elevated expression of estrogen and progesterone receptors and activation of the WNT/β-catenin pathway may prove useful as putative therapeutic targets in cases that do not respond to conventional therapy. Clinicians should be alerted to the possibility of familial adenomatous polyposis when a diagnosis of cribriform-morular variant of thyroid carcinoma is made. Instead of being considered as a variant of papillary thyroid carcinoma its designation as cribriform-morular thyroid carcinoma seems more appropriate.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (Translated Version)

Hereditary colorectal cancer accounts for less than 5% of all colorectal cancer cases. Some of the unique characteristics that are commonly encountered in cases of hereditary colorectal cancer include early age at onset, synchronous/metachronous occurrence of the cancer, and association with multiple cancers in other organs, necessitating different management from sporadic colorectal cancer. While the diagnosis of familial adenomatous polyposis might be easy because usually 100 or more adenomas that develop in the colonic mucosa are in this condition, Lynch syndrome, which is the most commonly associated disease with hereditary colorectal cancer, is often missed in daily medical practice because of its relatively poorly defined clinical characteristics. In addition, the disease concept and diagnostic criteria for Lynch syndrome, which was once called hereditary non-polyposis colorectal cancer, have changed over time with continual research, thereby possibly creating confusion in clinical practice. Under these circumstances, the JSCCR Guideline Committee has developed the "JSCCR Guidelines 2016 for the Clinical Practice of Hereditary Colorectal Cancer (HCRC)," to allow delivery of appropriate medical care in daily practice to patients with familial adenomatous polyposis, Lynch syndrome, or other related diseases. The JSCCR Guidelines 2016 for HCRC were prepared by consensus reached among members of the JSCCR Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR Guidelines 2016 for HCRC.

Prevalence of thyroid diseases in familial adenomatous polyposis: a systematic review and meta-analysis

Thyroid cancer (TC) is a known extra-intestinal manifestation and contributes to the mortality and morbidity in patients with familial adenomatous polyposis (FAP). Its exact prevalence is not well established and recent studies have shown an increasing number of TC in this patient population. The prevalence of benign thyroid masses and endocrinologic thyroid disorders are also poorly described. We conducted a systematic review and meta-analysis by using a random-effects model to characterize TC and estimated the prevalence of thyroid diseases in FAP patients. Twelve studies (n = 9821) were included. Pooled prevalence of TC, benign thyroid masses, and endocrinologic thyroid disorders in FAP were 2.6% [95% confidence interval (CI) 1.3-4.8], 48.8% [95% CI 33.8-64.0], and 6.9% [95% CI 4.5-10.3] respectively. Subgroup analyses revealed higher prevalence of TC in studies with fewer participants, studies that used screening ultrasound to diagnose TC, and studies that were published after 2002. TC diagnosis preceded the diagnosis of FAP in 34% of the patients. The means age at diagnosis of FAP and TC were 29 and 31 years, respectively. 95% of the patients were female and the most common pathology was of papillary subtype (83.3%). Most mutations (79.2%) were located at the 5' end of APC gene. In summary, benign thyroid disorders are common in FAP, yet, TC is an uncommon phenomenon. Certain patient subset, such as young female with APC mutation at the 5' end, might benefit from routine surveillance ultrasound.

Age- and Gender-Specific Risk of Thyroid Cancer in Patients With Familial Adenomatous Polyposis

CONTEXT

The cribriform-morula variant of papillary thyroid carcinoma (CMV-PTC) is a rare variant of PTC and is associated with familial adenomatous polyposis (FAP). However, the incidence and the nature of CMV-PTC among FAP patients have not been well characterized.

OBJECTIVE

The aim of this study was to determine the incidence and characteristics of thyroid cancer screened by neck ultrasonography for FAP patients. Design, Patients, and Intervention: A total of 129 FAP patients were included in this study. Neck ultrasonography was performed using a 12.0-MHz transducer probe. Germline APC gene mutation was examined for by the protein truncation test or DNA sequencing methods.

DESIGN, PATIENTS, AND INTERVENTION

A total of 129 FAP patients were included in this study. Neck ultrasonography was performed using a 12.0-MHz transducer probe. Germline APC gene mutation was examined for by the protein truncation test or DNA sequencing methods.

RESULTS

Twenty-one patients (16.3%) had solid nodules, and 24 patients (18.6%) had benign cystic nodules. In total, PTC was found in 11 patients (16% of the women and 0% of the men), 8 of which were CMV-PTC and the rest were classical PTC. In 17 female patients with thyroid nodules, CMV-PTC occurred in 8 of 9 patients who were 35 years age or younger but in none of the 8 patients who were older than 35 (P = .0004 by Fisher's exact test). The APC germline mutations in 8 patients with CMV-PTC were present at the 5' side of the profuse type of FAP region (codons 1249-1330).

CONCLUSIONS

The prevalence of CMV-PTC in FAP patients was higher than previously reported and this type of tumor was found preferentially in younger (under age 35) female patients with FAP in this cohort.

[Rare hereditary syndromes associated with polyposis and the development of malignant tumors]

Familial adenomatous polyposis (FAP) and Peutz-Jeghers syndrome are genetic diseases characterized by gastrointestinal polyps, extraintestinal manifestations, and autosomal dominant inheritance. The carriers of these diseases from early childhood are at risk for neoplasias at different sites, which are symptomatic at various ages.

AIM

to study the clinical organ-specific manifestations in patients with FAP and Peutz-Jeghers, genetics update and possibilities of diagnosis, monitoring, and treatment of these diseases.

MATERIAL AND METHODS

The authors give the results of their examination and follow-up of children with FAP and Peutz-Jeghers hamartoma-polypous syndrome. In addition, current data from PubMed, Medline (including reviews, original articles and case reports) were used.

RESULTS

The main clinical organ-specific signs of multiple tumors in FAP and Peutz-Jeghers syndrome are shown. Data on the assessment of a risk for malignant tumors at various sites in the affected patients and their family members at different ages are provided. Each of these syndromes has a dissimilar genetic foundation. FAP is caused by the germline mutations in the APC gene, Peutz-Jeghers syndrome is by the STK11 gene, which predispose individuals to specifically associated neoplasias and require different follow-up strategies. Information on a phenotype-genotype correlation may serve as a reference point for the possible severity and various manifestations of a disease. An update on the molecular pathogenesis of these diseases is considered.

CONCLUSION

Molecular genetic testing of the genes associated with FAP and Peutz-Jeghers syndromes makes it possible to timely recognize family members at high risk, to plan therapeutic strategy and to affect the course of a disease. The joint participation of pediatricians, proctologists, oncologists, morphologists, geneticists, and molecular biologists is essential to timely recognize the carriers of the syndromes and a better prognosis in these patients.

Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP), caused by a germline mutation in the adenomatous polyposis coli (APC) gene on chromosome 5q21, is an autosomal dominant disorder characterized by hundreds to thousands of adenomas throughout the gastrointestinal tract. A variety of extraintestinal manifestations, including thyroid, soft tissue, and brain tumors, may also be present. These patients inevitably develop colorectal carcinoma by the fourth decade of life. In this review, the pathology, epidemiology, and genetic features of FAP are discussed.

BRAFV600E-Associated Gene Expression Profile: Early Changes in the Transcriptome, Based on a Transgenic Mouse Model of Papillary Thyroid Carcinoma

Background

The molecular mechanisms driving the papillary thyroid carcinoma (PTC) are still poorly understood. The most frequent genetic alteration in PTC is the BRAFV600E mutation–its impact may extend even beyond PTC genomic profile and influence the tumor characteristics and even clinical behavior.

Methods

In order to identify BRAF-dependent signature of early carcinogenesis in PTC, a transgenic mouse model with BRAFV600E-induced PTC was developed. Mice thyroid samples were used in microarray analysis and the data were referred to a human thyroid dataset.

Results

Most of BRAF(+) mice developed malignant lesions. Nevertheless, 16% of BRAF(+) mice displayed only benign hyperplastic lesions or apparently asymptomatic thyroids. After comparison of non-malignant BRAF(+) thyroids to BRAF(−) ones, we selected 862 significantly deregulated genes. When the mouse BRAF-dependent signature was transposed to the human HG-U133A microarray, we identified 532 genes, potentially indicating the BRAF signature (representing early changes, not related to developed malignant tumor). Comparing BRAF(+) PTCs to healthy human thyroids, PTCs without BRAF and RET alterations and RET(+), RAS(+) PTCs, 18 of these 532 genes displayed significantly deregulated expression in all subgroups. All 18 genes, among them 7 novel and previously not reported, were validated as BRAFV600E-specific in the dataset of independent PTC samples, made available by The Cancer Genome Atlas Project.

Conclusion

The study identified 7 BRAF-induced genes that are specific for BRAF V600E-driven PTC and not previously reported as related to BRAF mutation or thyroid carcinoma: MMD, ITPR3, AACS, LAD1, PVRL3, ALDH3B1, and RASA1. The full signature of BRAF-related 532 genes may encompass other BRAF-related important transcripts and require further study.

Characteristics of benign and malignant thyroid disease in familial adenomatous polyposis patients and recommendations for disease surveillance

BACKGROUND

Familial adenomatous polyposis (FAP) is a hereditary colon cancer syndrome that involves multiple extracolonic organs, including the thyroid. Several studies have estimated the rate of thyroid cancer in FAP to occur at five times the rate of the general population, but no current consensus defines screening for thyroid cancer in this cohort. This study seeks to define the features of benign and malignant thyroid disease in FAP patients, to compare thyroid cancer cases found through screening with those found incidentally, and to propose disease surveillance recommendations.

METHODS

Prospective screening for early thyroid cancer detection with thyroid ultrasound (US) was performed on FAP patients at the time of annual colonoscopy since November 2008. Clinical and US data were reviewed to characterize the observed thyroid nodules. Nonscreening-detected cases (NSD) were found through review of the colon cancer registry database.

RESULTS

Eighteen NSD were found, compared with 15 screening-detected (SD) cases, out of 205 total patients screened (Mage=42 years; 55% female). The mean tumor size was larger in the NSD group than the SD group (p=0.04), and they tended to demonstrate more positive lymph nodes and more complications than the SD group. In the screened cohort, at least one thyroid nodule was detected in 106 (51.7%) patients, with 90% of these seen on initial exam. A total of 40/106 (37.7%) patients required fine-needle aspiration biopsy of a dominant nodule (Msize=14 mm), and 28/40 (70%) of these were performed at the first US visit. Suspicious US features were present in 16/40 (40%) patients, including five sub-centimeter nodules. Cytology and/or nodule US was abnormal in 15/205 screened patients, leading to surgery and revealing 14 papillary and one medullary thyroid cancer.

CONCLUSIONS

Given the age and sex distribution of the screened cohort, this study reveals a higher-than-expected prevalence of both benign and malignant thyroid disease in the FAP population. Additionally, SD cases seemed to consist of smaller-sized cancers that required less radical therapy compared to NSD cases. Since it was found that the initial US in the screening program accounted for the majority of detected nodules (90%) and biopsies (70%), baseline and subsequent thyroid US surveillance is recommended in all FAP patients.

ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes

This guideline presents recommendations for the management of patients with hereditary gastrointestinal cancer syndromes. The initial assessment is the collection of a family history of cancers and premalignant gastrointestinal conditions and should provide enough information to develop a preliminary determination of the risk of a familial predisposition to cancer. Age at diagnosis and lineage (maternal and/or paternal) should be documented for all diagnoses, especially in first- and second-degree relatives. When indicated, genetic testing for a germline mutation should be done on the most informative candidate(s) identified through the family history evaluation and/or tumor analysis to confirm a diagnosis and allow for predictive testing of at-risk relatives. Genetic testing should be conducted in the context of pre- and post-test genetic counseling to ensure the patient's informed decision making. Patients who meet clinical criteria for a syndrome as well as those with identified pathogenic germline mutations should receive appropriate surveillance measures in order to minimize their overall risk of developing syndrome-specific cancers. This guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

Sonographic and cytopathologic correlation of papillary thyroid carcinoma variants

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer and constitutes more than 70% of thyroid malignancies. Although TNM staging is the most widely used parameter for determination of therapeutic plans, recent studies have suggested that different histopathologic variants of PTC can also have different clinical courses and patient prognoses. Sonographic criteria for PTC are well established and include a taller-than-wide shape, an irregular margin, microcalcifications, and marked hypoechogenicity. The role of sonography has expanded to enable the characterization of PTC variants based on their sonographic features. Tall cell and diffuse sclerosing variants appear to have more aggressive clinical courses with unfavorable prognoses, whereas the more recently described cribriform-morular and Warthin-like variants have relatively indolent clinical courses. The prognoses of patients with follicular, solid, columnar cell, and oncocytic variants are still controversial and may be similar to the prognosis of conventional PTC. Understanding the sonographic characteristics of PTC variants with clinicopathologic correlation may be helpful for suggesting an appropriate treatment plan.

Thyroid cancer complicating familial adenomatous polyposis: mutation spectrum of at-risk individuals

Background

Lifetime risk of thyroid cancer associated with FAP has been reported as 1-2%. The mean age at diagnosis of thyroid carcinoma in FAP has been reported at 28 years. The aims of this paper are to better understand gene mutations associated with thyroid cancer and refine surveillance recommendations for patients with FAP.

Methods

We performed a search in Pubmed, Ovid Medline and Embase with the terms ("Thyroid Gland"[Mesh] OR "Thyroid Neoplasms"[Mesh]) AND "Adenomatous Polyposis Coli"[Meshdenomatous Polyposis Coli"[Mesh] to identify subjects with thyroid cancer and FAP. As a reference group for APC mutations in the unselected FAP population, we used the UMD-APC database referenced in the Orphanet portal, which includes APC mutation data on 2040 individuals with FAP.

Results

There were 115 reported cases of thyroid cancer in patients with FAP (95 female: 11 male) with an average age of 29.2 years. Gene mutation testing results were reported in 48 patients. On comparing the prevalence of APC mutation in the population of FAP patients with thyroid cancer and the prevalence of the same mutation in the reference population an increased odds ratio was evident in individuals harboring an APC mutation at codon 1061 (OR: CI 4.1: 1.7-8.9). Analysis of the prevalence of thyroid cancer in individuals with FAP segregated by the region of the gene affected shows an increased risk of thyroid cancer in individuals harboring mutations proximal to codon 512 (OR 2.6, p 0.0099).

Conclusions

There is increased risk for thyroid cancer in individuals with APC mutations at the 5' end (proximal to codon 528) along with the established high risk group harboring mutation at codon 1061. It is suggested that these patients might benefit from directed surveillance by annual ultrasound from age 18 years onwards.

Mutation analysis of the APC gene in unrelated Korean patients with FAP: four novel mutations with unusual phenotype

Germline mutations within the adenomatous polyposis coli (APC) gene are responsible for most cases of familial adenomatous polyposis (FAP), an autosomal dominantly inherited predisposition to colorectal cancer. To date more than 900 different APC germline mutations have been characterized worldwide demonstrating allelic heterogeneity. Here, we analyzed the APC gene in 23 DNA samples from unrelated Korean patients with the typical clinical symptoms of FAP by denaturing high-performance liquid chromatography (DHPLC) and direct sequencing. We identified 20 different APC sequence variants, including 9 truncating mutations, 1 missense mutation, 7 polymorphisms, and 3 intronic variants. Nine different truncating mutations, including four novel mutations (p.Leu180TyrfsX5, p.Gly567X, p.Ser1275PhefsX13, p.Leu1280CysfsX8), were detected. The most common mutation was a 5 bp deletion at codon 1,309 (p.Glu1309AspfsX4) as in Western studies. The next most common mutation was p.Ser1275PhefsX13 with a severe form of FAP with many extracolonic manifestations; this was a novel mutation identified in our study and may represent the second hot-spot mutation in a Korean population. Novel mutations are of particular interest because of the unusual phenotypic features shown by patients. In present study, we found new positions associated with thyroid cancer (codon 180) and desmoid tumor (codon 1,280), which have not been previously reported. The results of this molecular study have revealed the existence of novel pathogenic mutations in Korean patients with FAP. In addition to allowing phenotype-genotype correlations to be performed, these results are currently being used in genetic counseling and in patient care.

Papillary thyroid cancer in a patient with MUTYH-associated polyposis (MAP)

We describe a patient with MUTYH-associated polyposis diagnosed with colon cancer at 33 years of age, as well as gastric polyps at a later age. She was also diagnosed with papillary thyroid cancer at age 35. MUTYH-associated polyposis is an autosomal recessively inherited disease which has clinical overlap with Familial adenomatous polyposis and its attenuated form, in that it is associated with risk of colon cancer at a young age. Extra-intestinal cancers have also been reported in patients with MUTYH-associated polyposis; however the tumor spectrum is still evolving. National Comprehensive Cancer Network guidelines recommend screening for colon, duodenal and gastric polyps in individuals with MUTYH-associated polyposis. Screening for extra-intestinal cancers i.e. thyroid cancer is presently not part of these recommendations. These will likely continue to evolve as the MUTYH-associated polyposis tumor spectrum is better understood as a result of future case reports and research.

Gene variants associated to malignant thyroid disease in familial adenomatous polyposis: a novel APC germline mutation

BACKGROUND AND AIM

Familial adenomatous polyposis (FAP) is an autosomal inherited syndrome characterized by hundreds to thousands colorectal adenomatous polyps with oncological transformation lifetime risk of 100%. FAP is mainly associated with mutations in APC (autosomal dominant inheritance) or MUTYH (autosomal recessive inheritance) genes. Affected individuals are at increased risk of developing extra-intestinal tumors. Lifetime risk of developing thyroid carcinoma has been described in previous reports of about 2-12%, mainly in females, and the mean age is below 30 yr. About 95% of cancers are papillary thyroid carcinomas (PTC), mostly multifocal. The aim of this study was to evaluate the frequency of PTC among our series of FAP patients and to assess the type of gene mutation associated with the disease.

METHODS

Fifty-four subjects from 36 FAP families were selected (29 females/25 males) and the mean age (±SD) at diagnosis was 28.8±10.8 yr. All patients underwent blood examination for thyroid hormones and antibodies, germline mutational analysis of APC and/or MUTYH genes, thyroid ultrasound, and endocrinological evaluation.

RESULTS

In 13/54 (24.1%) subjects, an eumetabolic thyroid disease was found: plurinodular disease in 7/54 (13.0%); single nodule in 4/54 (7.4%); in 2/54 patients (3.7%), we found a malignant nodule characterized after total thyroidectomy as a classical PTC. Both patients were female and showed a classic FAP phenotype. Mutational analysis revealed in the first patient the APC germline mutation 3183_87del ACAAA and in the second patient the del9-10 (del9080dup11) novel APC variant; the first mutation has been already reported in association with PTC; to our knowledge the second mutation has never been previously reported in association with FAP.

CONCLUSIONS

In the population examined, the estimated prevalence of thyroid malignant diseases was 3.7%. In both patients, the identified APC gene pathogenetic variants mapped within the 5' region of the gene, previously reported as a PTC-associated mutational hot spot. Both patients had classic FAP phenotype and genetic analysis revealed two pathogenetic APC mutations: c.3183_87delACAAA, a recurrent pathogenetic variant and del9-10 (del9080dup11), a novel, not previously described genomic rearrangement. In agreement with previous studies, the morpho-functional surveillance of thyroid in FAP series should be recommended. A better insight into the overall genotype-phenotype correlation of APC gene mutations would be helpful for the identification of at-risk individuals.

Gene variants associated to malignant thyroid disease in familial adenomatous polyposis: a novel APC germline mutation

BACKGROUND AND AIM

Familial adenomatous polyposis (FAP) is an autosomal inherited syndrome characterized by hundreds to thousands colorectal adenomatous polyps with oncological transformation lifetime risk of 100%. FAP is mainly associated with mutations in APC (autosomal dominant inheritance) or MUTYH (autosomal recessive inheritance) genes. Affected individuals are at increased risk of developing extra-intestinal tumors. Lifetime risk of developing thyroid carcinoma has been described in previous reports of about 2-12%, mainly in females, and the mean age is below 30 yr. About 95% of cancers are papillary thyroid carcinomas (PTC), mostly multifocal. The aim of this study was to evaluate the frequency of PTC among our series of FAP patients and to assess the type of gene mutation associated with the disease.

METHODS

Fifty-four subjects from 36 FAP families were selected (29 females/25 males) and the mean age (±SD) at diagnosis was 28.8±10.8 yr. All patients underwent blood examination for thyroid hormones and antibodies, germline mutational analysis of APC and/or MUTYH genes, thyroid ultrasound, and endocrinological evaluation.

RESULTS

In 13/54 (24.1%) subjects, an eumetabolic thyroid disease was found: plurinodular disease in 7/54 (13.0%); single nodule in 4/54 (7.4%); in 2/54 patients (3.7%), we found a malignant nodule characterized after total thyroidectomy as a classical PTC. Both patients were female and showed a classic FAP phenotype. Mutational analysis revealed in the first patient the APC germline mutation 3183_87del ACAAA and in the second patient the del9-10 (del9080dup11) novel APC variant; the first mutation has been already reported in association with PTC; to our knowledge the second mutation has never been previously reported in association with FAP.

CONCLUSIONS

In the population examined, the estimated prevalence of thyroid malignant diseases was 3.7%. In both patients, the identified APC gene pathogenetic variants mapped within the 5' region of the gene, previously reported as a PTC-associated mutational hot spot. Both patients had classic FAP phenotype and genetic analysis revealed two pathogenetic APC mutations: c.3183_87delACAAA, a recurrent pathogenetic variant and del9-10 (del9080dup11), a novel, not previously described genomic rearrangement. In agreement with previous studies, the morpho-functional surveillance of thyroid in FAP series should be recommended. A better insight into the overall genotype-phenotype correlation of APC gene mutations would be helpful for the identification of at-risk individuals.

Three novel mutations of the APC gene in Korean patients with familial adenomatous polyposis

Germline mutations within the adenomatous polyposis coli (APC) gene are associated with familial adenomatous polyposis (FAP), an autosomal dominant disease predisposing individuals to colorectal cancer. Identification of APC mutations has important implications for genetic counseling and management of FAP patients. We examined the APC mutation status of 10 Korean FAP patients by polymerase chain reaction-direct sequencing method and found six APC mutations, including three novel mutations. Testing for MUTYH mutation was done for FAP patients in whom no mutation in the APC gene was identified. Three novel mutations (c.1654_1663delTCTTGGCGAG, c.3709C>T, and c.6092_6094delinsTT) and three previously reported mutations (c.3631_3632delAT, c.4438C>T, and c.4612_4613delGA) were detected. The MUTYH mutation was not detected in any of the four FAP patients without an APC mutation. This finding of three novel mutations in a group of Korean FAP patients broadens the spectrum of APC mutations.

Cribriform-morular variant of papillary thyroid carcinoma: molecular characterization of a case with neuroendocrine differentiation and aggressive behavior

We describe an especially aggressive case of cribriform-morular variant (C-MV) of papillary thyroid carcinoma (PTC) in a 42-year-old man with familial adenomatous polyposis who died with lung and brain metastases 17 months after thyroidectomy. The angioinvasive neoplasm combined a mixture of trabecular, solid, cribriform, and follicular patterns of growth with CD10+ morules. Follicles were devoid of colloid, and the nuclear features typical of PTC were present in some areas and missing in others. Tumor cells were positive for thyroid transcription factor-1 and, in 40% of the tumoral mass, also were positive for chromogranin and synaptophysin and were negative for thyroglobulin and calcitonin. Strong nuclear staining for beta-catenin was found in all tumor cells, as was positivity for p53 and cyclin D1. In addition to the germline heterozygous APC Ex 2-3 duplication mutation, a somatic homozygous silent p. Thr1493Thr gene variant was found in the neoplastic cells along with RET/PTC rearrangement. This tumor represents the first case of C-MV of PTC showing neuroendocrine differentiation.

Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72

Background

Familial adenomatous polyposis (FAP) is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations.

Methods

Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations.

Results

10 novel APC gene mutations were identified in 11 families. A broad spectrum of extracolonic manifestations was identified in most of these individuals. Two sisters with an insertion in codon 528 (c.1582_1583insGC) both showed severe phenotypes with classical polyposis, upper gastrointestinal polyps and thyroid cancer. A woman with a 3'APC mutation (c.5030_5031insAA) developed colon cancer at age 72 as the first manifestation of attenuated FAP.

Conclusion

With an increasing number of FAP families diagnosed, a broad and variable tumor spectrum and a high frequency of extracolonic manifestations are gradually recognized. We report novel APC mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.

Hereditary colorectal cancer syndromes: familial adenomatous polyposis and lynch syndrome

Familial colorectal cancer (CRC) accounts for 10% to 20% of all cases of CRC. Two major autosomal dominant forms of heritable CRC are familial adenomatous polyposis (FAP) and Lynch syndrome (also known as hereditary nonpolyposis colorectal cancer). Along with the risk for CRC, both syndromes are associated with elevated risk for other tumors. Improved understanding of the genetic basis of these diseases has not only facilitated the identification and screening of at-risk individuals and the development of prophylactic or early-stage intervention strategies but also provided better insight into sporadic CRC. This article reviews the clinical and genetic characteristics of FAP and Lynch syndrome, recommended screening and surveillance practices, and appropriate surgical and nonsurgical interventions.

Prevalence of thyroid cancer in familial adenomatous polyposis syndrome and the role of screening ultrasound examinations

BACKGROUND & AIMS

Thyroid carcinoma is an extraintestinal manifestation of familial adenomatous polyposis (FAP) syndrome, but the precise risk is unknown. The optimal approach for thyroid cancer screening has not been established. We sought to define the prevalence of thyroid cancer and the role of screening ultrasound in FAP patients.

METHODS

We performed a retrospective chart review of 51 patients with a proven diagnosis of FAP at a single tertiary institution. Clinical records, genetic test results, ultrasound examinations, and histopathology were reviewed.

RESULTS

Papillary thyroid cancer was diagnosed in 6 female patients (12%). The mean age of thyroid cancer diagnosis was 33 years, and mean tumor size was 12 mm. However, all patients had additional malignant foci that were small (1-9 mm), and none had suspicious features of malignancy on ultrasound. Of 28 patients who had at least one screening ultrasound, 22 (79%) had thyroid nodules, and 2 (7%) had papillary thyroid carcinoma. Of those with nodules, 68% had multinodular disease. A follow-up ultrasound in 12 patients after a mean of 15 months revealed no changes in either the number or size of nodules.

CONCLUSIONS

The 12% prevalence of thyroid cancer in this series of FAP patients is significantly higher than in previous reports. Among patients undergoing screening ultrasound, 7% had thyroid cancer. Nodular thyroid disease is very common in FAP. Because small nodules (<9 mm) might also be malignant, close follow-up with ultrasound and fine-needle aspiration might be warranted.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal-dominant colorectal cancer syndrome, caused by a germline mutation in the adenomatous polyposis coli (APC) gene, on chromosome 5q21. It is characterized by hundreds of adenomatous colorectal polyps, with an almost inevitable progression to colorectal cancer at an average age of 35 to 40 yr. Associated features include upper gastrointestinal tract polyps, congenital hypertrophy of the retinal pigment epithelium, desmoid tumors, and other extracolonic malignancies. Gardner syndrome is more of a historical subdivision of FAP, characterized by osteomas, dental anomalies, epidermal cysts, and soft tissue tumors. Other specified variants include Turcot syndrome (associated with central nervous system malignancies) and hereditary desmoid disease. Several genotype-phenotype correlations have been observed. Attenuated FAP is a phenotypically distinct entity, presenting with fewer than 100 adenomas. Multiple colorectal adenomas can also be caused by mutations in the human MutY homologue (MYH) gene, in an autosomal recessive condition referred to as MYH associated polyposis (MAP). Endoscopic screening of FAP probands and relatives is advocated as early as the ages of 10-12 yr, with the objective of reducing the occurrence of colorectal cancer. Colectomy remains the optimal prophylactic treatment, while the choice of procedure (subtotal vs proctocolectomy) is still controversial. Along with identifying better chemopreventive agents, optimizing screening of extracolonic cancers and applying new radiological and endoscopic technology to the diagnosis and management of extracolonic features are the major challenges for the future.

Clinical curiosity: Cribriform-morular variant of papillary thyroid carcinoma

BACKGROUND

There is an increasing awareness of the association of papillary thyroid carcinoma and familial adenomatous polyposis (FAP). Although the incidence is rare, most tend to occur in women. Several authors have described a distinctive histologic variant of papillary thyroid carcinoma, the cribriform-morular variant, which is associated with FAP but also may be encountered in patients with non-FAP. This diagnosis may precede the symptoms of colorectal polyposis.

METHODS

A healthy 36-year-old woman was seen with a left thyroid nodule, and a 34-year-old woman with FAP was seen with a right thyroid nodule; both masses were suspicious for papillary thyroid carcinoma. Both patients underwent total thyroidectomy.

RESULTS

Pathologic examination of both specimens revealed papillary thyroid carcinoma, cribriform-morular variant. The first patient subsequently underwent colonoscopy, which was negative for polyposis.

CONCLUSIONS

Patients diagnosed with the cribriform-morular variant of papillary thyroid cancer should be screened for the presence of FAP.

Identification of genomic deletions of the APC gene in familial adenomatous polyposis by two independent quantitative techniques

Large deletions in the APC (adenomatous polyposis coli) gene, causing familial adenomatous polyposis (FAP), cannot easily be detected by conventional mutation-detection techniques. Therefore, we have developed two independent quantitative methods for the detection of large deletions, encompassing one or more exons, of APC. Multiplex ligation-dependent probe amplification (MLPA) is performed in one reaction for the initial quantification of all APC exon copy numbers. Subsequently, quantitative real-time PCR (QRT-PCR) is used to verify the results obtained in the MLPA reaction. The identification of a deletion of the whole APC gene in a patient with classical FAP is described. The mutation was detected with the two quantitative methods and further verified on chromosomal level by the use of FISH (fluorescence in situ hybridization) on metaphase spreads. Furthermore, a large deletion covering exons 11-13 of the APC gene was detected in two apparently unrelated families. This deletion was further verified and characterized with long-range PCR. The MLPA test ensures a sensitive high-throughput screening for large deletions of the APC gene and can easily be implemented in the diagnostic testing for FAP.

Relationships between perinatal and maternal characteristics and hepatoblastoma: a report from the UKCCS

Within the context of a national population-based case-control study--the United Kingdom Childhood Cancer Study (UKCCS)--we aimed to explore relationships between perinatal and maternal factors and childhood hepatic tumours, for participants with data available from medical records. 26/28 children with hepatic tumours (22/24 hepatoblastomas, 4/4 hepatocellular carcinomas (HCC)) and 4753 age- and sex-matched controls were included. Polyhydramnios was associated with 0.9% of control pregnancies and 13.6% of case pregnancies (Odds Ratio (OR)=28.64, 95% Confidence Interval (CI)=6.94-118.21, P<0.0001); eclampsia or severe pre-eclampsia complicated the pregnancies of 16.7% of mothers whose children developed hepatoblastoma compared with 0.5% of control pregnancies (OR=52.50, 95% CI=10.75-257.05, P<0.0001). Three children with hepatoblastoma weighed <1500 g at birth, two of whom weighed <1000 g (OR for birthweight <1500 g=69.00, 95% CI=11.98-397.17, P<0.0001). Of children with hepatoblastoma, 50% (11/22) had records of congenital anomalies, as did two of their mothers. Three mothers of children with hepatoblastoma had diagnoses of cancer--two of papillary carcinoma of the thyroid and one of acute lymphoblastic leukaemia (ALL). Paediatricians and others should be alert to the possibility of familial or genetic syndromes in children with hepatoblastomas. Potential links between maternal pre-eclampsia, low birthweight and subsequent malignancy merit further investigation. Hepatoblastoma is an extremely rare childhood tumour, but understanding the mechanism(s) underlying severe pre-eclampsia and eclampsia may also shed light on factors that contribute to the development of hepatoblastoma.

Cancer genetics in primary care

The cloning of two major breast cancer susceptibility genes, BRCA1 and BRCA2, in 1994 and 1995 and the subsequent development of commercial genetic testing has brought hereditary cancer genetics into the public eye. In addition to DNA-based genetic testing, new strategies and treatments have been developed to provide accurate assessment of cancer risk and to reduce the chances of cancer developing in the future. This increasing scientific and public attention has prompted some cancer patients and their families to find out whether they "have the cancer gene" and has placed more responsibility on primary care clinicians to identify people who should be referred for specialized services of hereditary cancer genetics.

Exclusion of an extracolonic disease modifier locus on chromosome 1p33–36 in a large Swiss familial adenomatous polyposis kindred

Familial adenomatous polyposis (FAP), an autosomal dominantly inherited colorectal cancer predisposition syndrome, displays considerable inter- and intrafamilial phenotypic heterogeneity, which represents a major problem in genetic counselling of APC mutation carriers. The Min mouse model indicated a putative disease modifier locus on chromosome 4, which is syntenic to human chromosome 1p35-36. This finding was subsequently supported by parametric and nonparametric linkage analyses in FAP families, however, without identifying functional variants in candidate genes. Recently, germline mutations in the base-excision repair gene MYH (1p33-34) have been described in patients with multiple adenomas, pointing to a possible role as disease modifier in FAP. Here, we present critical reassessment of one of the largest FAP kindreds published, which was previously used in linkage mapping of 1p35-36. In this family, all affected members harbour the same APC germline mutation (5945delA), but display marked phenotypic variability, in particular regarding the occurrence of extracolonic disease that segregates in several branches of the family tree. Using updated clinical information, additional mutation carriers and polymorphic markers, fine mapping of the critical region as well as mutation analysis of the MYH gene were performed. These investigations allowed us to significantly exclude (i) the 1p33-36 region as a modifier locus and (ii) MYH as a modifier gene for extracolonic disease in this FAP kindred. Our results do not eliminate 1p33-36 from suspicion in other families, but clearly indicate that in our family linkage analysis of further putative candidate regions is necessary to identify a disease modifier locus in FAP.