The genetic basis of familial adenomatous polyposis and its implications for clinical practice and risk management.
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ABSTRACT:
SUBMITTER: Leoz ML
PROVIDER: S-EPMC4404874 | biostudies-literature | 2015
REPOSITORIES: biostudies-literature
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The genetic basis of familial adenomatous polyposis and its implications for clinical practice and risk management.
Leoz Maria Liz ML Carballal Sabela S Moreira Leticia L Ocaña Teresa T Balaguer Francesc F
The application of clinical genetics 20150416
Familial adenomatous polyposis (FAP) is an inherited disorder that represents the most common gastrointestinal polyposis syndrome. Germline mutations in the APC gene were initially identified as responsible for FAP, and later, several studies have also implicated the MUTYH gene as responsible for this disease, usually referred to as MUTYH-associated polyposis (MAP). FAP and MAP are characterized by the early onset of multiple adenomatous colorectal polyps, a high lifetime risk of colorectal canc ...[more]
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Project description:IntroductionIn Japanese patients with familial adenomatous polyposis (FAP), colectomy tends to be postponed or avoided.AimThis study aimed to clarify the current clinical practice from a Japanese multicenter cohort study database.MethodsWe analyzed the records of 250 patients with non-dense FAP who did not require colorectal cancer removal. The clinical outcomes were compared between patients who received colectomy (n = 142) (Group A) and those who did not receive colectomy (n = 108) (Group B).ResultsThe colectomy rate based on the age at the final follow-up examination was 46%, 60%, 54%, 65%, at ≤29, 30-39, 40-49, and ≥ 50 years, respectively (P = .11). The development of colorectal cancer did not differ between Groups A and B (25% vs 22% P = .67); however, colorectal cancer was diagnosed at the Tis stage in 88% of the patients with colorectal cancer in Group B, and 34% of the patients with colorectal cancer in Group A (P < .01). Regarding survival, all patients in Group B were alive at the final follow-up examination. In contrast, six patients in Group A died, including three patients with desmoid tumors and one with colon cancer.ConclusionOver one-third of patients with non-dense FAP (polyps ≤ 1000) in Japan did not receive colectomy at >30 years of age, and patients who managed without colectomy showed acceptable survival with the early diagnosis of colorectal cancer, and a very low incidence of desmoid tumor development, indicating that this approach represents a potential option for the management of selected non-dense FAP patients.
| S-EPMC9628228 | biostudies-literature
Project description:BackgroundPatients with familial adenomatous polyposis (FAP) are at increased risk of developing gastric adenomas. There is limited understanding of their clinical course and no consensus on management. We reviewed the management of gastric adenomas in patients with FAP from two centers.MethodsPatients with FAP and histologically confirmed gastric adenomas were identified between 1997 and 2018. Patient demographics, adenoma characteristics, and management/surveillance outcomes were collected.ResultsOf 726 patients with FAP, 104 (14 %; 49 female) were diagnosed with gastric adenomas at a median age of 47 years (range 19 - 80). The median size of gastric adenomas was 6 mm (range 1.5 - 50); 64 (62 %) patients had adenomas located distally to the incisura. Five patients (5 %) had gastric adenomas demonstrating high-grade dysplasia (HGD) on initial diagnosis, distributed equally within the stomach. The risk of HGD was associated with adenoma size (P = 0.04). Of adenomas > 20 mm, 33 % contained HGD. Two patients had gastric cancer at initial gastric adenoma diagnosis. A total of 63 patients (61 %) underwent endoscopic therapy for gastric adenomas. Complications occurred in three patients (5 %) and two (3 %) had recurrence, all following piecemeal resection of large (30 - 50 mm) lesions. Three patients were diagnosed with gastric cancer at median follow-up of 66 months (range 66 - 115) after initial diagnosis.ConclusionsWe observed gastric adenomas in 14 % of patients with FAP. Of these, 5 % contained HGD; risk of HGD correlated with adenoma size. Endoscopic resection was feasible, with few complications and low recurrence rates, but did not completely eliminate the cancer risk.
| S-EPMC8315898 | biostudies-literature
Project description:Colorectal cancer (CRC) is one of the most common forms of cancer worldwide and familial adenomatous polyposis (FAP) accounts for approximately 1% of all CRCs. Adenomatous polyposis syndromes can be divided into; familial adenomatous polyposis (FAP) - classic FAP and attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), NTHL1-associated polyposis (NAP) and polymerase proofreading-associated polyposis (PPAP). The polyposis syndromes genetics and clinical manifestation of disease varies and cases with clinical diagnosis of FAP might molecularly show a different diagnosis. This review examines different aspects of the adenomatous polyposis syndromes genetics and clinical manifestation of disease; in addition the genotype-phenotype and modifier alleles of FAP will be discussed. New technology has made it possible to diagnose some of the APC mutation negative patients into their respective syndromes. There still remain many molecularly undiagnosed adenomatous polyposis patients indicating that there remain causative genes to be discovered and with today's technology these are expected to be identified in the near future. The knowledge about the role of modifier alleles in FAP will contribute to improved pre-symptomatic diagnosis and treatment. New novel mutations will continually be discovered in genes already associated with disease and new genes will be discovered that are associated with adenomatous polyposis. The search for modifier alleles in FAP should be made a priority.
| S-EPMC5353802 | biostudies-literature
Project description:BackgroundInternational chemoprevention preferences and approaches in Lynch syndrome (LS) and APC-associated polyposis, including Familial adenomatous polyposis (FAP) and attenuated FAP (AFAP) have not been previously explored.AimTo describe current chemoprevention strategies for patients with LS or FAP/AFAP (referred to collectively as FAP) practiced by members of four international hereditary cancer societies through administration of a survey.ResultsNinety-six participants across four hereditary gastrointestinal cancer societies responded to the survey. Most respondents (91%, 87/96) completed information regarding their demographics and practice characteristics relating to hereditary gastrointestinal cancer and chemoprevention clinical practices. Sixty-nine percent (60/87) of respondents offer chemoprevention for FAP and/or LS as a part of their practice. Of the 75% (72/96) of survey respondents who were eligible to answer practice-based clinical vignettes based off of their responses to ten barrier questions regarding chemoprevention, 88% (63/72) of those participants completed at least one case vignette question to further characterize chemoprevention practices in FAP and/or LS. In FAP, 51% (32/63) would offer chemoprevention for rectal polyposis, with sulindac - 300 mg (18%, 10/56) and aspirin (16%, 9/56) being the most frequently selected options. In LS, 93% (55/59) of professionals discuss chemoprevention and 59% (35/59) frequently recommend chemoprevention. Close to half of the respondents (47%, 26/55) would recommend beginning aspirin at time of commencement of the patient's first screening colonoscopy (usually at age 25yrs). Ninety-four percent (47/50) of respondents would consider a patient's diagnosis of LS as an influential factor for aspirin use. There was no consensus on the dose of aspirin (≤100 mg, >100 mg - 325 mg or 600 mg) to offer patients with LS and there was no agreement on how other factors, such as BMI, hypertension, family history of colorectal cancer, and family history of heart disease, would affect the recommendation for aspirin use. Possible harm among older patients (>70 years) was identified as the most common reason to discourage aspirin use.ConclusionAlthough chemoprevention is widely discussed and offered to patients with FAP and LS by an international group of hereditary gastrointestinal cancer experts, there is significant heterogeneity in how it is applied in clinical practice.
| S-EPMC10247284 | biostudies-literature
Project description:Familial adenomatous polyposis (FAP) is an autosomal dominant cancer predisposition syndrome marked by extensive colorectal polyposis and a high risk of colorectal cancer (CRC). Having access to screening and enrollment programs can improve survival for patients with FAP by enabling them to undergo surgery before the development of colorectal cancer. Provided that there are a variety of surgical options available to treat colorectal polyps in patients with adenomatous polyposis, the appropriate surgical option for each patient should be considered. The gold-standard treatment to reduce this risk is prophylactic colectomy, typically by the age of 40. However, colectomy is linked to morbidity and constitutes an ineffective way at preventing extra-colonic disease manifestations, such as desmoid disease, thyroid malignancy, duodenal polyposis, and cancer. Moreover, extensive studies have been conducted into the use of chemopreventive agents to prevent disease progression and delay the necessity for a colectomy as well as the onset of extracolonic disease. The ideal chemoprevention agent should demonstrate a biologically plausible mechanism of action and provide safety, easy tolerance over an extended period of time and a lasting and clinically meaningful effect. Although many pharmaceutical and non-pharmaceutical products have been tested through the years, there has not yet been a chemoprevention agent that meets these criteria. Thus, it is necessary to develop new FAP agents that target novel pathways, such as the mTOR pathway. The aim of this article is to review the prior literature on FAP in order to concentrate the current and future perspectives of diagnosis and treatment. In conclusion, we will provide an update on the diagnostic and therapeutic options, surgical or pharmaceutical, while focusing on the potential treatment strategies that could further reduce the risk of CRC.
| S-EPMC10439286 | biostudies-literature
Project description:BACKGROUND: Mutations of the APC gene cause familial adenomatous polyposis (FAP), a hereditary colorectal cancer predisposition syndrome. AIMS: To conduct a cost comparison analysis of predictive genetic testing versus conventional clinical screening for individuals at risk of inheriting FAP, using the perspective of a third party payer. METHODS: All direct health care costs for both screening strategies were measured according to time and motion, and the expected costs evaluated using a decision analysis model. RESULTS: The baseline analysis predicted that screening a prototype FAP family would cost $4975/ pound3109 by molecular testing and $8031/ pound5019 by clinical screening strategy, when family members were monitored with the same frequency of clinical surveillance (every two to three years). Sensitivity analyses revealed that the genetic testing approach is cost saving for key variables including the kindred size, the age of screening onset, and the cost of mutation identification in a proband. However, if the APC mutation carriers were monitored at an increased (annual) frequency, the cost of the genetic screening strategy increased to $7483/ pound4677 and was especially sensitive to variability in age of onset of screening, family size, and cost of genetic testing of at risk relatives. CONCLUSIONS: In FAP kindreds, a predictive genetic testing strategy costs less than conventional clinical screening, provided that the frequency of surveillance is identical using either strategy. An additional significant benefit is the elimination of unnecessary colonic examinations for those family members found to be non-carriers.
| S-EPMC1727488 | biostudies-other
Project description:BACKGROUND Familial adenomatous polyposis (FAP), which has a very high tendency of progression to colorectal cancer, is mainly caused by mutations of the adenomatous polyposis coli (APC) gene. This study systematically screened the APC mutations and observed the correlation of APC mutations with clinical manifestations of FAP. MATERIAL AND METHODS Eighty subjects (probands and their family members of 22 FAP pedigrees) were enrolled, underwent abdominal ultrasound, computed tomography, and colonoscopic examinations, and were assessed for APC mutations between January 2010 and June 2015 at Tianjin Union Medical Center. Peripheral blood was collected from subjects, and DNA was extracted and screened for APC mutations using multiplex ligation-dependent probe amplification for large-fragment deletions or PCR-denaturing high-performance liquid chromatography with DNA sequencing for micromutations. RESULTS Nineteen of 22 FAP pedigrees were found to have mutations of APC, and 17 types APC mutations were identified. All the mutations were heterozygosity with autosomal dominant inheritance. APC mutations included 8 caused by frameshift, 3 by aberrant splicing, 2 by missense mutation, 2 by nonsense mutation, and 2 by large-fragment deletion. Frameshift mutation was the most common type of APC mutation, and Coding DNA Sequence 15 was the most common mutation site. Five novel APC mutations, including 1 with large-fragment deletion, were identified. CONCLUSIONS We systematically screened 17 mutations of APC from 22 Chinese pedigrees with FAP. This study will broaden the spectrum of known APC germline mutations and help understand the types and distribution of APC mutations among Chinese patients with FAP.
| S-EPMC6542301 | biostudies-literature
Project description:Familial adenomatous polyposis (FAP) is a well-defined autosomal dominant predisposition to the development of polyposis in the colon and rectum at unusually early ages. The first symptoms of FAP are diarrhea and blood in the stool. Weight loss and weaknesses occur after the development of advanced tumour. The incidence of the FAP disorder is one per 10000 newborns. There are high levels of heterogeneity with regard to the number and timing of the occurrence of polyps. The classical form of FAP is characterized by the presence of more than 100 polyps, which appear in the second decade of life. The average time of occurrence of polyps is 15 years. The earliest symptoms of polyposis have been observed in a three-year-old child. The polyps are characterized by large potential for the development towards malignant tumour. Malignancy can occur from late childhood onwards. Attenuated adenomatous polyposis coli is characterized by a more benign course of disease in contrast to classical FAP. The occurrence of FAP is associated with mutations in the APC tumour suppressor gene, which was described in 1991. The APC gene is located on chromosome 5q21 and is involved in cell proliferation control. A recessive form of adenomatous polyposis is caused by mutations in the base excision repair gene - MUTYH gene. The MUTYH gene is involved in repairing DNA lesions as a result of oxidative DNA damage. MUTYH associated polyposis (MAP) is a predisposition to the development of polyps of the colon but the number of polyps is lower in comparison to classical FAP. The high risks of cancer observed in these two diseases make them important medical issues. Molecular studies of colonic polyposis have been performed in Poland for over fifteen years. A DNA Bank for Polish FAP patients was established at the Institute of Human Genetics in Poznan in which DNA samples from 600 FAP families have been collected.
| S-EPMC3843547 | biostudies-literature
Project description:ObjectiveIn this study, we aimed to describe the clinical features, management, and outcomes of desmoid tumors (DTs) in familial adenomatous polyposis (FAP) patients at a high-volume sarcoma center.MethodsConsecutive patients with FAP and DTs were identified from our institutional databases (1985-2021). Patient demographics, treatment, and outcomes were described. Categorical data were compared using Fisher's exact test, and Kaplan-Meier curves were used to estimate progression-free survival (PFS).ResultsForty-five patients with 67 DTs were identified: 39 mesenteric or retroperitoneal (58.2%), 17 abdominal wall (25.4%), 4 extremity (6%), 4 breast (6%) and 3 back (4.4%). Severe DT symptoms were present in 12 patients (26.7%). Initial treatments per tumor were observation in 30 (44.8%) DTs, chemotherapy in 15 (22.4%) DTs, surgery in 10 (14.9%) DTs, and other systemic therapies in 10 (14.9%) DTs. The majority of DTs remained stable with observation or a single intervention (77.8%). Median PFS was 23.4 years (95% confidence interval 7.6-39.2). In the 12 severely symptomatic patients, four patients required more than two interventions for DT control. At a median follow-up of 6.0 years (range 0.7-35.8 years), 33 (73.3%) patients were alive with disease, 7 (15.6%) were alive without disease, and 5 (11.1%) died of other causes. No patients died of DT-related complications.ConclusionsThe majority of DTs in FAP patients remained stable with observation or a single intervention. There were no DT-related deaths; however, 12 of 45 patients (26.7%) experienced significant tumor morbidity and required more interventions for disease control. Further studies on quality of life are required.
| S-EPMC10215061 | biostudies-literature
Project description:There have been significant advances in our knowledge about the molecular changes that precede and accompany the development of inherited predispositions to colorectal cancer. In this review the clinical relationship to the molecular changes associated with the polyposis syndromes is presented. The aim is to put into context the diverse findings that have been shown to be associated with the development of colorectal cancer in persons who harbor a predisposition to develop disease at unusually early ages. The main focus will be on familial adenomatous polyposis as it serves as a model disease and is the most extensively studied of all of the polyposis syndromes. In addition some information is provided that explains the relationship between a germline change in one gene and what consequences that can have for a particular cell and the development of disease.
| S-EPMC2840009 | biostudies-other