For Familial Adenomatous Polyposis Research Articles

Abstract SY07-01: The adenomatous polyposis coli protein makes multiple contributions to architecture of gut epithelial cells and tissue

Abstract Gut epithelium can be subject to acute and chronic inflammatory conditions, bacterial infections, parasitic colonization and cancer. It is the most dynamic epithelium in the adult body and relies on cellular processes that govern all epithelial tissues. Understanding how it is normally maintained and how molecular changes create cellular and tissue changes in disease is key for developing effective treatments and detection methods. We are using changes in gut epithelium that accompany colorectal cancer as a model for understanding changes in epithelial physiology in disease. The earliest identifiable molecular change in sporadic colorectal cancer is mutation of the Adenomatous polyposis coli (APC) gene. Such mutations are usually truncation mutations and are also responsible for familial adenomatous polyposis (FAP), a familial form of colorectal cancer. Understanding how molecular changes in APC drive such cellular and tissue changes will yield important information about normal and disease-associated physiology. APC is a multifunctional protein that contributes to proliferation, differentiation, cell-cell and cell-substrate adhesion, apoptosis, and migration. APC thus represents a central node between seemingly distinct signalling networks. Many of the protein interactions that contribute to these diverse functions have been described. The first binding partner identified for APC was beta-catenin, a protein that supports adhesion proteins and activates transcription factors that drive genes characteristic of less differentiated, more proliferative cells. APC helps to target beta-catenin for proteasomal degradation. This is regulated by Wnt signalling and places APC at the core of a pathway that is crucial for the development of many tissues and organs. APC also interacts directly with cytoskeletal proteins and their regulators. These interactions contribute directly to cell migration and adhesion, but also cell division and apoptosis. Mutations in APC cause stabilisation of beta-catenin, which results in continued proliferation and decreased differentiation. In this context, the additional loss of the beta-catenin-independent functions of APC (genetic instability, decreased cell migration and decreased apoptosis) are particularly relevant because they confer a significant advantage to cells. Thus APC is a gatekeeper that ensures the fidelity of the processes that govern normal tissue maintenance in gut but also other epithelia. Work in my laboratory aims to understand the spectrum of APC functions, how they are regulated and coordinated with each other and how they contribute to overall epithelial biology. To this end we use a host of techniques that span multiple levels of resolution. This includes biochemical assays to reveal the molecular mechanisms that underpin APC interactions, high-resolution live imaging of cells and whole tissues to elucidate spatial and temporal regulation of APC protein complexes, and functional readouts to establish the contribution of APC to cell migration, differentiation, proliferation, adhesion, and cell death. One area of particular interest is contribution of APC and its associated pathways to the maintenance of stem cells in gut epithelium. Ultimately, we aim to use data on APC and its interactions to create an interaction network for APC that integrates the best available supporting evidence in a coherent model that describes the molecular basis for the contribution of APC to the normal biology of gut epithelium. We aim to integrate this with three- and four-dimensional models of tissue architecture that are informed by our detailed measurement of tissue architecture in normal and precancerous tissue. My presentation will provide an up-to-date summary of these studies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr SY07-01. doi:10.1158/1538-7445.AM2011-SY07-01

Ileal pouch and related complications: spectrum of imaging findings with emphasis on MRI

Proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the established surgical therapy for familial adenomatous polyposis (FAP) and refractory ulcerative colitis (UC). Despite general patient satisfaction with preserved fecal continence, this procedure is associated with a significant long-term morbidity approaching 70% after 10 years, and with a non-negligible rate of pouch failure leading to removal and permanent ileostomy. Following a concise description of the surgical technique, the normal imaging appearance of the ileal "pouch" reservoir at pelvic CT and MRI is explained. Since awareness of their imaging appearances is needed for a correct diagnosis, we discuss and illustrate common and unusual pouch-related complications, including pouchitis and irritable pouch disease; anastomotic leakages and pelvic abscess collections; fistulas involving the ano-perianal region, urinary bladder, vagina, perineal skin, and subcutaneous planes; anal stenosis and small-bowel obstruction. In our experience, pelvic contrast-enhanced MRI has proven invaluable for the diagnostic assessment of patients with suspected pouch-related complications, allowing differentiation of uncomplicated pouchitis from pelvic sepsis, the latter requiring aggressive therapy and possible even in patients with normal endoscopic findings.

Evaluation of physician knowledge and referral practices for colorectal cancer (CRC) genetic risk assessment: The experience at the Hospital of University of Pennsylvania (HUP).

379 Background: 3-5% of CRCs are due to inherited genetic mutations. We surveyed knowledge and practices of academic physicians for identification and care of individuals at risk for inherited CRC. Methods: 264 physicians (oncologists (ON), gastroenterologists (GA), surgeons, internists, gynecologists, and radiation oncologists) at HUP were invited to participate in a web-based 9-min survey. The ability to obtain appropriate medical history and to make referral to genetic services was evaluated. Knowledge of hereditary CRC syndromes was examined both pre and post viewing of an educational web-page on inherited CRCs. Mantel-Haenszel, Fisher exact, and McNemar statistical tests were applied. Results: Response rate was 33.3%; and of those, 97.4% accessed the educational webpage. In the cohort, 98.9 % obtained a medical history very frequently (VF), 88.6% obtained cancer history in 1st and 45.5% in the 2nd degree relatives VF, and 63.9% asked about the relatives' age at time of cancer diagnosis VF. Of those most likely to care for patients with CRC, the GA more frequently asked about relatives' age at cancer diagnosis (p=0.014) and family history of polyps (p< 0.001) than ON. GA were more likely than ON to refer patients for genetic counseling (73.9% vs. 36.8%, p=0.008). GA had superior knowledge of the availability of genetic testing for Lynch syndrome (LS) (95.6% GA vs. 63.2% ON, p=0.005) and for familial adenomatous polyposis (FAP) (100.0% GA vs. 65.8% ON, p<0.001). For the entire cohort, the educational intervention raised awareness of genetic testing for LS (64.5% pre vs. 94.7% post, p<0.001), FAP (69.7% pre vs. 97.4% post, p<0.001), and Peutz-Jeghers Syndrome (31.6% pre vs. 84.2% post, p<0.001); and it significantly improved recognition of LS family pedigrees and selection of appropriate surveillance. Conclusions: Of the respondents, GA are more likely to obtain a detailed family history, utilize genetic services, and have a greater awareness of the availability of genetic testing, than ON. A simple educational intervention improves physician knowledge on inherited CRC risk recognition and surveillance recommendations. No significant financial relationships to disclose.

The pathogenesis of primary pouchitis following ileal pouch-anal anastomosis: a review of current hypotheses

Primary pouchitis is a common complication of ileal pouch-anal anastomosis following proctocolectomy in patients treated for ulcerative colitis (UC), but is un-usual for those treated for familial adenomatous polyposis (FAP). While a number of theories as to the pathogenesis of this inflammatory condition have been proposed, no single one has been wholly satis-factory. Much research has been devoted to investi-gating a link between the pathogenic factors involved in UC, but not FAP, and those underlying pouchitis. The contribution of sulfate-producing bacteria has also been explored. The role of other intraluminal factors, such as short chain fatty acids and unconju-gated bile salts, has also been investigated. A unifying theory of a multi-step process might explain the pathogenesis of pouchitis, but further research is re-quired to proof causation. It is likely that pouchitis develops as a result of a combination of genetic, im-munological, microbial and metabolic factors. Future insight into the causes of pouchitis may eventually allow for the development of more effective treat-ments.

Ileal reservoir with ileo-anal anastomosis: Long-term complications

Coloproctectomy with ileo-anal anastomosis (CP-IAA) has been in use for 30 years. This intervention is the standard technique when surgery is indicated for familial adenomatous polyposis (FAP) and for ulcerative colitis (UC). Although the surgery is safe with mortality of less than 1%, it is associated with a morbidity of 18-70%. We thought a literature review about long-term complications would be enlightening. Pouchitis is the most common complication; it occurs in 70% of patients over 20 years follow-up; small bowel obstruction affects 25% of patients and pelvic sepsis occurs in 20-30% within 10 years. CP-IAA can impact the patient's sexual life due to erectile and ejaculatory dysfunction, dyspareunia, and incontinence of stool during sexual intercourse. Nevertheless, patients with long-standing UC describe an overall improvement in their sexual function after surgery. The failure rate varies from 3.5 to 15%; major causes of failure are sepsis, unrecognized Crohn's disease, and poor functional results. Cases of dysplasia and cancer have been reported in the reservoir, but more particularly when there is retained colonic glandular mucosa. The transitional zone should be monitored whenever there are risk factors for colon neoplasia. The relatively high morbidity of CP-IAA should not overshadow the good functional results of this technique.

Abstract 939: Chemoprevention of familial adenomatous polyposis by EM011 in the ApcMin/+ mouse model

Abstract Abstract Germline mutation of the tumor suppressor gene, adenomatous polyposis coli (APC), is responsible for familial adenomatous polyposis (FAP) with nearly 100% risk for colon cancer at an early age. Although FAP is involved in only 1% of all colon cancer cases, over 80% of sporadic cancers harbor somatic mutations of APC. We show here that 9-bro-noscapine (EM011), a rationally-designed synthetic derivative of a natural non-toxic tubulin-binding alkaloid−noscapine, that reduces the dynamics of microtubules, causes a reversible G2/M arrest in wild type mouse embryonic fibroblasts (MEFs), but an aberrant exit from a brief mitotic block, followed by apoptosis in MEFs isolated from ApcMin/+ mice. Furthermore, both β-catenin levels and activity fell to half the original levels with a concomitant reduction of cell proliferation-inducing cyclin D1, c-Myc, and induction of cytostatic protein p21 prior to caspase-3 activation. Additionally, we show a statistically significant reduction in the number of newly emerging intestinal polyps (to 35% compared with untreated mice) as well as the mean size of polyps (to 42% compared with untreated mice) in EM011-treated ApcMin/+ mice as compared to their sham-treated control littermates. The remaining polyps in the EM011 treated group of ApcMin/+ mice showed evidence of elevated apoptosis as revealed by immunohistochemistry. We failed to detect any evidence of histopathological and hematological toxicities following EM011 treatment. Taken together, our data are persuasive that a clinical trial of EM011 is possible for the prevention/amelioration of polyposis in FAP patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 939.

Detection of epithelial apoptosis in pelvic ileal pouches for ulcerative colitis and familial adenomatous polyposis

BackgroundIleal pouch-anal anastomosis (IPAA) is the surgical procedure of choice for patients with refractory ulcerative colitis (UC) and for familial adenomatous polyposis (FAP) with many rectal polyps. Pouchitis is one of the more frequent complications after IPAA in UC patients; however, it is rare in FAP.ObjectiveEvaluate pro-apoptotic activity in endoscopically and histological normal mucosa of the ileal pouch in patients with UC and FAP.MethodsEighteen patients (nine with UC and nine with FAP) with J pouch after total rectocolectomy were studied. Biopsies were obtained from the mucosa of the pouch and from normal ileum. The specimens were snap-frozen and the expressions of Bax and Bcl-2 were determined by immunoblot of protein extracts and by immunohistochemistry analysis. FADD, Caspase-8, APAF-1 and Caspase-9 were evaluated by immunoprecipitation and immunoblot.ResultsPatients with UC had significantly higher protein levels of Bax and APAF-1, Caspase-9 than patients with FAP, but were similar to controls. The expressions of Bcl-2 and FADD, Caspase-8 were similar in the groups. Immunohistochemistry for Bax showed less intensity of immunoreactions in FAP than in UC and Controls. Bcl-2 immunostaining was similar among the groups.ConclusionPatients with FAP present lower levels of pro-apoptotic proteins in all methods applied, even in the absence of clinical and endoscopic pouchitis and dysplasia in the histological analysis. These findings may explain a tendency of up-regulation of apoptosis in UC patients, resulting in higher rates of progression to pouchitis in these patients, which could correlate with mucosal atrophy that occurs in inflamed tissue. However, FAP patients had low pro-apoptotic activity in the mucosa, and it could explain the tendency to low cell turn over and presence of adenomas in this syndrome.

Gardner-Fibrom

Gardner fibroma represents a rare and recently described soft tissue tumor entity in children and young adults. It consists of haphazardly arranged coarse and hyalinized collagen fibers combined with loosely arranged bland spindle and fibroblastic cells. The case of a 13-year-old male patient with Gardner fibroma and osteoma and multicentric desmoid type fibromatosis in his mother is presented with detection of a (heterozygotic) germline mutation of the APC gene leading to a de novo stop codon (deletion of base pairs 5033-5036). FISH analysis revealed a structural loss of heterozygosity (LOH) in the APC gene on chromosomal locus 5q21 in one out of five analysed desmoids of the mother, no LOH of APC gene in the Gardner fibroma. Gardner fibroma in children and young adults may serve as an indicator lesion for familial adenomatous polyposis (FAP), Gardner syndrome, a familial desmoid type fibromatosis without other manifestations of APC or a new APC gene mutation. For the clinician, this diagnosis should be commented upon accordingly by the surgical pathologist. As the result of a detected APC gene mutation, continuous follow-up for the development of colorectal tumors and desmoid type fibromatosis as well as a familial screening for FAP is recommended.

Long-Term Outcome of Metachronous Rectal Cancer Following Ileorectal Anastomosis for Familial Adenomatous Polyposis

BackgroundTotal colectomy with ileorectal anastomosis (IRA) for familial adenomatous polyposis (FAP) carries a potential risk of metachronous cancer in the residual rectum. This study evaluated the risk of cancer development in the residual rectum. MethodsNinety-six patients who underwent initial surgery for prevention and cure of FAP were studied, and a clinicopathologic comparison was conducted between 59 patients who underwent IRA and 24 who underwent total proctocolectomy. ResultsThe 5-year overall survival rates were 94% after IRA and 95% after total proctocolectomy with no significant difference. The incidence of dense-type rectal polyps (4/17, 24%) was significantly higher in patients who developed metachronous rectal cancer following IRA compared to that in patients who did not (1/39, 3%). Moreover, 60% of patients with dense-type colon polyps developed metachronous rectal cancer compared to 24% in patients without and 80% of those with dense type rectal polyps developed metachronous rectal cancer compared to 25% without. Endoscopic surveillance of the eight Tis or T1 patients was performed at intervals of 6 months to 1 year after IRA but was not performed in three T3 patients for more than 2 years. ConclusionsEffective IRA requires selection of patients without invasive rectal cancer and without dense rectal polyps in whom long-term postoperative follow-up of the residual rectum is possible.

Attitudes toward genetic testing in childhood and reproductive decision-making for familial adenomatous polyposis

Childhood DNA testing, prenatal diagnosis (PND) and preimplantation genetic diagnosis (PGD) are available for familial adenomatous polyposis (FAP). However, the use of PND and PGD is controversial. The purpose of this study was to investigate attitudes toward, and experiences with, childhood DNA testing, PND and PGD among members of families at high risk for FAP. In this nationwide, cross-sectional study, questionnaires were sent to individuals from families at high risk for FAP assessing attitudes toward and experiences with childhood testing, PND and PGD, as well as several sociodemographic, clinical and psychosocial variables. Of the individuals from FAP families invited to participate in the study, 525 members participated (response rate=64%). Most parents who had children who were minors (n=93) (82%) were satisfied with the DNA testing procedure. One-third of all individuals wanted DNA testing for their children before age 12. Forty percent of FAP patients indicated that the disease influenced their desire to have children. Only 15% considered termination of pregnancy for FAP acceptable. Approximately 30% of individuals with a FAP diagnosis and their partners considered PND and PGD as acceptable for themselves. A positive attitude was associated with higher levels of guilt and a positive attitude toward termination of pregnancy. Importantly, of those with FAP at childbearing age, 84% had had no previous information at all about either PND or PGD. Future efforts should be aimed at educating FAP family members about reproductive options, allowing them to make an informed choice about family planning. Routine discussion of all reproductive options with a medical specialist should be encouraged.

The challenge of developmentally appropriate care: predictive genetic testing in young people for familial adenomatous polyposis

Predictive genetic tests for familial adenomatous polyposis (FAP) are routinely offered to young people during early adolescence. While this is not controversial, due to the medical benefit conferred by the test, it is nonetheless challenging as a consequence of the stage of life of the young people, and the simultaneous involvement of multiple family members. Despite these challenges, it is possible to ensure that the test is offered in such a way that it actively acknowledges and facilitates young people's developing autonomy and psychosocial well-being. In this paper we present findings from ten in-depth interviews with young people who have undergone predictive genetic testing for FAP (four male, six female; five gene-positive, five gene-negative; aged 10-17 years at the time of their predictive test; aged 12-25 years at the time of their research interview). We present five themes that emerged from the interviews which highlight key ethical challenges associated with such testing. These are: (1) the significance of the test; (2) young people's lack of involvement in the decision to be tested; (3) young people's limited understanding; (4) provision of the blood test at the first visit; and (5) group testing of family members. We draw on these themes to make eight recommendations for future practice. Together, these recommendations highlight the importance of providing developmentally appropriate care to young people undergoing predictive genetic testing for FAP.

A Targeted Constitutive Mutation in the Apc Tumor Suppressor Gene Underlies Mammary But Not Intestinal Tumorigenesis

Germline mutations in the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominant hereditary predisposition to the development of multiple colorectal adenomas and of a broad spectrum of extra-intestinal tumors. Moreover, somatic APC mutations play a rate-limiting and initiating role in the majority of sporadic colorectal cancers. Notwithstanding its multifunctional nature, the main tumor suppressing activity of the APC gene resides in its ability to regulate Wnt/β-catenin signaling. Notably, genotype–phenotype correlations have been established at the APC gene between the length and stability of the truncated proteins encoded by different mutant alleles, the corresponding levels of Wnt/β-catenin signaling activity they encode for, and the incidence and distribution of intestinal and extra-intestinal tumors. Here, we report a novel mouse model, Apc1572T, obtained by targeting a truncated mutation at codon 1572 in the endogenous Apc gene. This hypomorphic mutant allele results in intermediate levels of Wnt/β-catenin signaling activation when compared with other Apc mutations associated with multifocal intestinal tumors. Notwithstanding the constitutive nature of the mutation, Apc +/1572T mice have no predisposition to intestinal cancer but develop multifocal mammary adenocarcinomas and subsequent pulmonary metastases in both genders. The histology of the Apc1572T primary mammary tumours is highly heterogeneous with luminal, myoepithelial, and squamous lineages and is reminiscent of metaplastic carcinoma of the breast in humans. The striking phenotype of Apc +/1572T mice suggests that specific dosages of Wnt/β-catenin signaling activity differentially affect tissue homeostasis and initiate tumorigenesis in an organ-specific fashion.

Pancreas-preserving total duodenectomy versus standard pancreatoduodenectomy for patients with familial adenomatous polyposis and polyps in the duodenum

Pancreas-preserving total duodenectomy (PPTD) was introduced as a replacement for pancreatoduodenectomy (PD) for familial adenomatous polyposis (FAP). This study analysed the results of PPTD in the Netherlands and reviewed the relevant literature. All 26 patients who underwent PPTD for FAP in four centres in the Netherlands between January 2000 and January 2007 were compared with a group of 77 patients who had PD for ampulla of Vater adenocarcinoma at one centre during the same interval. Morbidity rates were similar after PPTD for FAP (16 patients, 62 per cent) and PD for ampulla of Vater adenocarcinoma (44 patients, 57 per cent) (P = 0.694). One patient (4 per cent) died after PPTD and two (3 per cent) after PD. A review of the literature, including patients from the present study, found that 71 patients had PPTD, with postoperative morbidity in 36 (51 per cent) and one death (1 per cent). In publications containing a total of 94 patients who underwent PD for FAP, 43 (46 per cent) developed complications and three (3 per cent) died. PPTD has similar short-term results to PD in terms of morbidity and mortality.

Mutated in colorectal cancer, a putative tumor suppressor for serrated colorectal cancer, selectively represses β-catenin-dependent transcription

Mutated in colorectal cancer (MCC) was originally identified as a candidate gene for familial adenomatous polyposis (FAP) but further study identified adenomatous polyposis coli (APC) as responsible for FAP and the physiologic/pathologic roles of MCC remained poorly understood. Recently, MCC promoter methylation was discovered as a frequent early event in a distinct subset of precursor lesions and colorectal cancer (CRC) associated with the serrated CRC pathway. Here we provide the first evidence of the biological significance of MCC loss in CRC and the molecular pathways involved. We show MCC expression is dramatically decreased in many CRC cell lines and the distinct subset of sporadic CRC characterized by the CpG island methylator phenotype and BRAF(V600E) mutation due to promoter methylation as reported previously. Importantly, we find MCC interacts with beta-catenin and that reexpression of MCC in CRC cells specifically inhibits Wnt signaling, beta-catenin/T-cell factor/lymphoid-enhancer factor-dependent transcription and cellular proliferation even in the presence of oncogenic mutant APC. We also show that MCC is localized in the nucleus and identify two functional nuclear localization signals. Taken together, MCC is a nuclear, beta-catenin-interacting protein that can act as a potential tumor suppressor in the serrated CRC pathway by inhibiting Wnt/beta-catenin signal transduction.

DHPLC Analysis of Adenomatous Polyposis Coli (APC) Mutations Using Ready-to-Use APC Plates: Simple Detection of Multiple Base Pair Deletion Mutations

The adenomatous polyposis coli (APC), which is the susceptible gene for familial adenomatous polyposis (FAP) and sporadic colorectal cancer, spans 15 exons. The open reading frame of APC is 8529 bp, which encodes 2843 amino acids. Conventional genetic screening involves extensive time as well as high cost and labor. Thus, we developed a novel APC ready-to-use plate for high-throughput mutational analysis by denaturing high performance liquid chromatography (DHPLC). To prepare the ready-to-use APC plate, all 38 primer pairs and PCR mixtures were aliquoted into individual wells of a 96-well plate, and frozen at -20 degrees C until use. All 38 PCR primers were designed to be amplified at the same temperature (52 degrees C). We examined a total of 27 FAP patient samples with APC germline mutations (17 for multiple bp deletions, 1 for 1 bp deletion, 9 for nonsense mutations) and 50 APC-negative noncarriers. All 17 multiple bp deletion mutations were detected during the initial 50 degrees C running analysis and thus ruled out for further analyses. All other mutations were clearly detected under specific optimized conditions. More than 50% of the APC germline mutations were multiple base pair deletions and efficiently selected by omitting time-consuming partial denaturing conditions.

Spontaneous regression of rectal polyps following abdominal colectomy and ileorectal anastomosis for familial adenomatous polyposis, without sulindac treatment: Report of four cases

The only curative treatment for familial adenomatous polyposis (FAP) is prophylactic surgery and the two most popular options are total colectomy with ileorectal anastomosis and restorative proctocolectomy with ileal pouch-anal anastomosis. Today, ileal pouch-anal anastomosis has gained wider acceptance as a safer procedure, but ileorectal anastomosis still remains an option, especially for young patients with a moderate phenotype of the disease and limited polyps in the rectum. Partial or complete regression of rectal polyps after total colectomy with ileorectal anastomosis and treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) such as sulindac is reported in up to 80 % of patients. However, in some cases such regression can be spontaneous and long-lasting following total colectomy and ileorectal anastomosis, without further treatment with NSAIDs. We present the cases of four patients with FAP treated by colectomy and ileorectal anastomosis, who had immediate, complete spontaneous regression of multiple polyps in the rectal stump, with no further need for sulindac treatment.

Strategies and outcomes of PGD of familial adenomatous polyposis

Owing to adult onset of hereditary cancer, prenatal diagnosis (PND) raises numerous ethical issues on the acceptability to terminate an affected pregnancy (TOP). PND for these disorders is often considered as unacceptable by couples as well as geneticists and legal or ethical authorities, but preimplantation genetic diagnosis (PGD), even if subject to controversy, seems to be a more acceptable option. Therefore, many couples, who do not want to transmit their cancer to their children, consider PGD as their only reproductive option. This article describes our experience of PGD for familial adenomatous polyposis (FAP). Twelve couples were referred between 2000 and 2005. We developed PGD tests to detect the mutation alone, but we rapidly set up multiplex PCR combining mutation detection and indirect diagnosis. Finally, we set up duplex and triplex indirect diagnoses to be able to offer a PGD, whatever mutation was involved in familial cases. PGD strategies were based on (i) a new double allele-specific PCR approach (D-ARMS) allowing the detection of the wild-type and mutated allele; (ii) PCR fragments sizing and (iii) restriction length polymorphisms. For the 12 referrals, we developed eight tests, and 11 cycles have been performed for four couples, resulting in eight embryo transfers and five pregnancies, with the birth of one healthy boy and two ongoing pregnancies. We are now able to propose PGD to most couples at risk of transmitting FAP to their offspring, whether the mutation is familial or occurred de novo.

Restorative proctocolectomy and ileal pouch-anal anastomosis for familial adenomatous polyposis revisited

Since restorative proctocolectomy (RPC) with ileal-pouch anal anastomosis (IPAA) removes the entire diseased mucosa, it has become firmly established as the standard operative procedure of choice for familial adenomatous polyposis (FAP). Many technical controversies still persist, such as mesenteric lengthening techniques, close rectal wall proctectomy, endoanal mucosectomy vs. double stapled anastomosis, loop ileostomy omission and a laparoscopic approach. Despite the complexity of the operation, IPAA is safe (mortality: 0.5-1%), it carries an acceptable risk of non-life-threatening complications (10-25%), and it achieves good long-term functional outcome with excellent patient satisfaction (over 95%). In contrast to the high incidence in patients operated for ulcerative colitis (UC) (15-20%), the occurrence of pouchitis after IPAA seems to be rare in FAP patients (0-11%). Even after IPAA, FAP patients are still at risk of developing adenomas (and occasional adenocarcinomas), either in the anal canal (10-31%) or in the ileal pouch itself (8-62%), thus requiring lifelong endoscopic monitoring. IPAA operation does not jeopardise pregnancy and childbirth, but it does impair female fecundity and has a low risk of impairment of erection and ejaculation in young males. The latter can almost completely be avoided by a careful "close rectal wall" proctectomy technique. Some argue that low risk patients (e.g. <5 rectal polyps) can be identified where ileorectal anastomosis (IRA) might be reasonable. We feel that the risk of rectal cancer after IRA means that IPAA should be recommended for the vast majority of FAP patients. We accept that in some very selected cases, based on clinical and genetics data (and perhaps influenced by patient choice regarding female fecundity), a stepwise surgical strategy with a primary IPA followed at a later age by a secondary proctectomy with IPAA could be proposed.

Luminal delivery and dosing considerations of local celecoxib administration to colorectal cancer

The purpose of this study was to develop a biodegradable drug platform composed of chitosan and guar gum and to explore the possibility of using it for local adjuvant or neoadjuvant therapy of colorectal cancer. Celecoxib (Cx), a chemopreventative drug for familial adenomatous polyposis (FAP) and under trial for reducing post surgical colorectal malignancies, was selected as a model drug for this topical system because of the contraindications that are associated with its systemic administration. Films made of chitosan (Ct) and guar gum (GG) were prepared, characterized for equilibrium swelling, mucoadhesion, in vitro and in vivo degradation and loaded with Cx. Short term dosing studies in vitro were performed in the HT-29 colon carcinoma cell line that was incubated with Cx using the MTT test to assess IC50. The impact of a single high dose was evaluated and compared with a repeating low-dose regimen. In vivo dosing experiments with Cx were performed in the perfused intestine of the anaesthetized rat. Measuring tissue LDH assessed epithelium injury. Mechanical, mucoadhesion and in vitro degradation of the polysaccharide films were dictated by manipulating the ratios of Ct and GG. The addition of rat cecal contents to the dissolution medium increased the total Cx released from those films containing high amounts of GG. MTT reduction, a measure of cell proliferation, diminished as a function of increasing drug concentration and exposure time in the HT-29 cell line studies. Local high concentrations of Cx were shown to impede the proliferation of cancer cells directly, while chemoprevention has been demonstrated with low Cx doses. Healthy cells were shown to be sensitive to high Cx doses. Maximum therapeutic efficiency in the context of minimal healthy tissue exposure would thus be predicted utilizing a local delivery system such as the proposed adhesive, biodegradable polysaccharide composites.

Meta-analysis of observational studies of ileorectal versus ileal pouch–anal anastomosis for familial adenomatous polyposis

Surgery for familial adenomatous polyposis (FAP) aims to minimize cancer risk while providing good functional outcome. Colectomy with ileorectal anastomosis and proctocolectomy with ileal pouch-anal anastomosis both offer this, but there is no clear consensus about which is better. This is a meta-analysis of comparative studies published between 1991 and 2003 reporting early and late postoperative adverse events, functional outcomes and quality of life. Twelve studies containing 1002 patients (53.4 per cent ileal pouch, 46.6 per cent ileorectal anastomosis) were identified. Bowel frequency (weighted mean difference 1.62 (95 per cent confidence interval (c.i.) 1.05 to 2.20)), night defaecation (odds ratio (OR) 6.64 (95 per cent c.i. 2.99 to 14.74)) and use of incontinence pads (OR 2.72 (95 per cent c.i. 1.02 to 7.23)) were significantly less in the ileorectal group, although faecal urgency was reduced with the ileal pouch (odds ratio 0.43 (95 per cent c.i. 0.23 to 0.80)). Reoperation within 30 days was more common after ileal pouch construction (23.4 versus 11.6 per cent; OR 2.11 (95 per cent c.i. 1.21 to 3.70)). There was no significant difference between the techniques in terms of sexual dysfunction, dietary restriction, or postoperative complications. Rectal cancer was a diagnosis only in the ileorectal group (5.5 per cent). Ileal pouch and ileorectal anastomoses have individual merits. Further research is needed to determine which most benefits patients with FAP.