Lack of telomerase in desmoids occurring sporadically and in association with familial adenomatous polyposis

BACKGROUND: Telomerase activity may be required for unlimited growth of cells and is repressed in most somatic tissues, but is detectable in immortal cell lines, germ cells, many malignancies and some benign lesions. Desmoids are proliferative, locally invasive, non-metastasizing fibromatous tumours which rarely regress. They occur frequently in familial adenomatous polyposis (FAP), causing significant morbidity and death. Telomerase activity was assayed in desmoids from patients with and without FAP to assess the role of telomerase in the development of these lesions, and its potential as a prognostic marker and possible target for treatment. METHODS: Protein extracts from 11 desmoids from nine patients with FAP, and ten desmoids from ten patients without FAP, were analysed for telomerase activity by the telomeric repeat amplification protocol, a sensitive polymerase chain reaction-based assay. Six fibrosarcomas and a fibrosarcoma cell line were used as positive controls; all displayed telomerase activity. RESULTS: No telomerase activity was detected in any of the 21 desmoids studied. CONCLUSION: These results indicate that desmoid tumours are one of the intriguing exceptions to the emerging view that re-expression of telomerase activity accompanies the development of preneoplastic and neoplastic tissues, and suggest that alternative mechanisms may operate in these proliferative neoplasms.     

Management of desmoid tumors in patients after ileal pouch-anal anastomosis for familial adenomatous polyposis

PURPOSE: The aim of this study was to review the management of desmoid tumors in patients who have undergone ileal pouch-anal anastomosis for familial adenomatous polyposis and their outcome. METHODS: A retrospective review of case notes was undertaken in a series of 196 patients with familial adenomatous polyposis who had had an ileal pouch-anal anastomosis. Eleven patients were identified in whom desmoid tumor had developed (4 male; median age, 30 (range, 16-43) years). RESULTS: Desmoid tumors developed in the abdominal wall alone in 4 of 11 patients. Three enlarging tumors were resected with no subsequent recurrence. No patient received adjuvant treatment and pouch function remained stable at a median follow-up of eight years. Mesenteric desmoid tumors developed in seven patients; the pouch has been excised in two because of ischemia; two other patients have had defunctioning stomas created because of slow progression of their desmoid tumors. One patient had a single-lumen pouch excised and a new S-pouch inserted, with no subsequent recurrence of the desmoid tumor, and in two patients the mesenteric desmoid tumor has remained unchanged. All of these patients received long-term Clinoril (sulindac, Merck & Co., Inc., West Point, PA). Although there has been no significant deterioration in pouch function in patients in whom the pouch remains in situ, the pouch function was significantly worse compared with a control group of patients after ileal pouch-anal anastomosis for familial adenomatous polyposis in whom desmoid tumors did not develop. CONCLUSION: Desmoid tumors developed in 5.6 percent of 196 patients after ileal pouch-anal anastomosis for familial adenomatous polyposis. No patient with abdominal-wall desmoid tumor had a recurrence after local excision. By contrast, mesenteric desmoid tumors eventually resulted in pouch failure in four of seven affected patients.     

Genetic counselling and gene mutation analysis in familial adenomatous polyposis in Western Australia

OBJECTIVE: To assess the provision of accurate pre-symptomatic genetic testing with DNA analysis and appropriate counselling for individuals and families known to be at high risk of developing familial adenomatous polyposis coli (FAP). PATIENTS AND METHODS: Thirty-one families with clinically and pathologically documented FAP were ascertained from the Western Australian Polyposis Registry. DNA was collected from over 200 individuals in these families to establish their genetic risk status for FAP, either by direct mutation analysis, or by linkage analysis. Individuals undergoing DNA testing were given intensive psychosocial support and counselling. RESULTS: In 19 families DNA-based counselling could not be offered because either the adenomatous polyposis coli (APC) gene mutation could not be detected or there were insufficient family members for linkage analysis. Gene testing yielded mutations of the APC gene in 87 individuals from 12 families; by gene tracking (or linkage analysis) in three families and by mutation analysis in the remaining nine (four of which had only one affected individual). DNA results conformed with a definite clinicopathological diagnosis in 27 FAP patients and, of the remaining 60 high-risk subjects tested, 14 had inherited the mutated APC gene. CONCLUSIONS: DNA analysis allowed accurate genetic counselling for 12 of 31 families affected by FAP, thus improving the medical and personal management in asymptomatic people who would otherwise be subjected to the uncertainty of long term surveillance and repeated colonic examinations. In future a superior biomolecular approach to gene mutation analysis, such as the protein truncation test, will facilitate management for most FAP individuals and families.     

Screening for APC mutations based on detection of truncated APC proteins

Mutation of the adenomatous polyposis coli (APC) gene is frequently found in colorectal tumors from both familial adenomatous polyposis (FAP) and non-FAP patients. Analysis of APC mutation is time-consuming and costly due to the large size of the APC gene. As the majority of APC mutations result in the truncation of gene products, the detection of truncated APC proteins may be used as a screening method for APC mutations. The aim of this study is to establish a practical method of detecting truncated APC proteins for the screening of APC mutations. APC proteins in human colorectal cancer cell lines were analyzed by western blotting. Truncated APC proteins were expressed in all of the colorectal cancer cell lines studied. Two species of truncated APC proteins were expressed in two cell lines. Western blotting is a rapid, reliable screening method for APC mutations and provides information on both alleles.     

Germline mutations in the 3' part of APC exon 15 do not result in truncated proteins and are associated with attenuated adenomatous polyposis coli

Familial adenomatous polyposis (FAP) is an inherited predisposition to colorectal cancer characterized by the development of numerous adenomatous polyps predominantly in the colorectal region. Germline mutations in the adenomatous polyposis coli (APC) gene are responsible for most cases of FAP. Mutations at the 5' end of APC are known to be associated with a relatively mild form of the disease, called attenuated adenomatous polyposis coli (AAPC). We identified a frameshift mutation in the 3' part of exon 15, resulting in a stop codon at 1862, in a large Dutch kindred with AAPC. Western blot analysis of lymphoblastoid cell lines derived from affected family members from this kindred, as well as from a previously reported Swiss family carrying a frameshift mutation at codon 1987 and displaying a similar attenuated phenotype, showed only the wild-type APC protein. Our study indicates that chain-terminating mutations located in the 3' part of APC do not result in detectable truncated polypeptides and we hypothesize that this is likely to be the basis for the observed AAPC phenotype.     

Genotype-phenotype correlations in attenuated adenomatous polyposis coli

Germ-line mutations of the tumor suppressor APC are implicated in attenuated adenomatous polyposis coli (AAPC), a variant of familial adenomatous polyposis (FAP). AAPC is recognized by the occurrence of <100 colonic adenomas and a later onset of colorectal cancer (age >40 years). The aim of this study was to assess genotype-phenotype correlations in AAPC families. By protein-truncation test (PTT) assay, the entire coding region of the APC gene was screened in affected individuals from 11 AAPC kindreds, and their phenotypic differences were examined. Five novel germ-line APC mutations were identified in seven kindreds. Mutations were located in three different regions of the APC gene: (1) at the 5' end spanning exons 4 and 5, (2) within exon 9, and (3) at the 3' distal end of the gene. Variability in the number of colorectal adenomas was most apparent in individuals with mutations in region 1, and upper-gastrointestinal manifestations were more severe in them. In individuals with mutations in either region 2 or region 3, the average number of adenomas tended to be lower than those in individuals with mutations in region 1, although age at diagnosis was similar. In all AAPC kindreds, a predominance of right-sided colorectal adenomas and rectal polyp sparing was observed. No desmoid tumors were found in these kindreds. Our data suggest that, in AAPC families, the location of the APC mutation may partially predict specific phenotypic expression. This should help in the design of tailored clinical-management protocols in this subset of FAP patients.     

Molecular biological background of FAP and HNPCC, and treatment strategies of both diseases depend upon genetic information

Recent advancement of molecular biology disclose responsible genes of FAP(familial adenomatous polyposis) and HNPCC(hereditary non polyposis colorectal cancer). Gardner Syndrome is now categorized as subtype of FAP. Turcot Syndrome is now known as a heterogeneous disease. Turcot Syndrome caused by APC gene develops medulloblastoma and Turcot Syndrome caused by mismatch repair gene develops glioblastoma. Because of the discovery of APC gene, the presymptomatic diagnosis of asymptomatic gene carriers are now available and preventive surgery can be planned. FAP patients with mutated APC gene between codon 1250 and 1464 shows severe phenotype. It is known that FAP patient whose APC gene mutation locates at codon 1309 develops cancer 10 years earlier in comparison to the rest of the cases. Consequently risky rectal mucosa should be removed in this group of patients. As for HNPCC, presymptomatic diagnosis is still not possible because the penetrance rate has not been estimated yet and some additional responsible genes are expected to be discovered. Replication error, mutator phenotype of mismatch repair gene is useful indicator to predict second primary cancers. When the patient in a HNPCC family develops adenoma with microsatellite mistability, preventive colectomy might be one of the surgical option with the informed consent of the patient.     

Measurement of histidinohydroxylysinonorleucine and hydroxyproline in skin collagen by reversed-phase high-performance liquid chromatography after 9-fluorenylmethyl chloroformate labeling

The management of intra-abdominal desmoid tumors in patients with familial adenomatous polyposis (FAP) is very difficult. Non-steroidal anti-inflammatory drugs (NSAIDs), anti-estrogenic agents, and steroids are most commonly used, because surgical removal of these tumors may result in severe morbidity, with local recurrence being common. We report a patient with FAP and intra-abdominal desmoid tumors that regressed markedly after prednisolone therapy. The patient, a 38-year-old woman, had undergone total colectomy and ileorectal anastomosis with a diagnosis of FAP with colon cancer. Approximately 17 months after the surgery, she noticed an elastic firm lump in the abdominal wall. She also experienced lower abdominal distension. Computed tomography (CT) of the lower abdomen showed an invasive heterogenous low-density mass occupying the intra-abdominal space. She was treated with sulindac, NSAID, at 300 mg/day, the diagnosis being intra-abdominal desmoid tumors. She exhibited an intestinal obstruction about 9 months after the initiation of sulindac therapy. We changed the treatment and began prednisolone (initial dose, 40 mg/day). This treatment was continued for two years; subsequently, the lesions regressed markedly. She is currently well, more than 3 years after the withdrawal of prednisolone.     

Combined effects of insulin treatment and adipose tissue-specific agouti expression on the development of obesity

BACKGROUND & AIMS: Infantile and childhood liver tumors have been found in 0.42% of individuals with a germline mutation in the adenomatous polyposis coli (APC) gene. This study analyzed a hepatocellular adenoma of a 2-year-old child at risk for familial adenomatous polyposis to identify genetic alterations in hepatic tumors initiated by APC germline mutations. METHODS: Mutation screening was performed for the APC gene (protein truncation test and DNA sequence analysis), p53 gene (complementary DNA cloning and sequencing), and members of the Ras gene family (complementary DNA sequence analysis). RESULTS: Both the mother and child had a germinal CGA-->TGA transition at codon 1451 leading to an Arg1451Ter stop mutation in the APC gene. Loss of the wild-type APC allele as a second hit revealed hemizygosity of the inherited mutation in the tumor. Furthermore, a CGC-->CAC transition in the p53 gene of the adenoma resulted in an Arg-->His missense mutation in codon 175. No loss of heterozygosity was detected at the p53 locus. Ras gene mutations were not found. CONCLUSIONS: Biallelic inactivation of APC gene and p53 mutation are early events in hepatocellular tumorigenesis. Additional reports will confirm whether inherited APC gene mutations between codon 1444 and 1578 increase the risk for hepatic tumors.     

Diagnosis and management of entrapped embolus through a patent foramen ovale

In the present study, we used five different polymorphic markers to construct the haplotype at the adenomatous polyposis coli (APC) locus in families with familial adenomatous polyposis (FAP) and in the normal Italian population. Non-ambiguous haplotypes were reconstructed from 246 normal chromosomes and 65 FAP chromosomes. In the control population, the four polymorphisms intragenic to APC gave rise to 16 haplotypes, the most common of which (II and XV) accounted for over 50% of all chromosomes. In FAP patients, 13 haplotypes were found but their distribution was not statistically different from normal subjects. Eighty complete chromosomal haplotypes (many fewer than the theoretical maximum of 208) for the five polymorphic sites assayed were observed in the control population, 35 being found in the FAP patients. We compared the distribution of these haplotypes within the two groups; no statistically significant differences between normal and FAP chromosomes were found. The elevated heterogeneity of FAP chromosomes was clearly confirmed by the observation that 19 patients who carried one or other of the two most common APC mutations (nt 3183 and nt 3927) showed 18 different haplotypes. On the basis of these results, we were not able to identify a founder FAP chromosome. Various mechanisms are presented to explain this observation.     

Tumor suppressor genes with special emphasis on the APC tumor suppressor gene

Tumor suppressor genes play a central role in the genesis and progression of human cancers. Genetic alterations of tumor suppressor genes have been found in a variety of hereditary and nonhereditary cancers. Persons that carry a hereditary mutation in tumor suppressor genes are strongly predisposed to one or more kinds of cancer. This review brings current developments in the field of tumor suppressor genes. Special emphasis is dedicated to recently discovered tumor suppressor gene APC (adenomatous polyposis coli) whose mutations are responsible for familial adenomatous polyposis (FAP). The known mutations of the APC gene are described. The role of the APC gene in tumor development, as well as the possibility for presymptomatic genetic testing is also discussed in the paper.     

Familial adenomatous polyposis coli in the Czech population. I. Detection of an additional 3 mutations out of a total of 7 in exon 15 of the APC gene

BACKGROUND: Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disease characterized by multiple adenomatous polyps in the colon which progress to carcinoma. FAP is caused by germ-line mutation of the tumor-suppressor adenomatous polyposis coli (APC) gene, the structure and coding sequence of which have been known from 1991. The diagnosis of FAP has classically been based on the detection of multiple colorectal adenomas, often after carcinoma development. Presymptomatic genetic testing for the presence of an allele carrying the FAP mutation is now possible using a variety of techniques. METHODS AND RESULTS: The present paper is the first part of an analysis of 37 different Czech families with 83 members affected by FAP. Our goal is to identify the mutation characteristic for each family for early diagnosis of FAP. We screened clinically manifest representatives of nine families for mutations in exon 15 of the APC gene. First, we searched for the mutation hot spots (codons 1061 and 1309, respectively) and later for the entire exon 15. Denatured gradient gel electrophoresis (DGGE) of amplified regions ov exon 15 has been used to identify DNA sequence variations followed by sequencing verification. In seven patients, seven different mutations in exon 15 of APC gene, four deletion mutants (5-base deletions in codons 1061 and 1309, 1-base deletion in codons 759 and 7-base deletion combined with a 2-base insertion in codon 712), one insertion mutation (1-base/A/insertion in codon 1554) and two point mutations (C to T and C to A substitutions in codons 737 and 935, respectively, in both cases leading to formation of stop codons) have been found. CONCLUSIONS: From seven different mutations found, 4 mutations have been previously described (mutations in codons 935, 1061, 1309 and 1554), 3 mutations in the APC gene are described here for the first time, namely the mutations in codons 712, 759 and 767.     

Desmoid tumor sensitive to tamoxifen

BACKGROUND: Desmoid tumors are the second leading cause of mortality in patients with familial adenomatous polyposis who have undergone proctocolemy. Both medical and surgical treatment of these non-metastasizing but locally aggressive tumors are difficult. CASE REPORT: A 20-years-old woman consulted 6 years after coloproctectomy for familial adenomatous polyposis. A mesenteric desmoid tumor was found. Resection was not possible. The tumor progressed under sulindac treatment and subocclusion developed. The patient was given tamoxifen, 20 mg/d and the size of the tumor began to regress within a few days together with pain and signs of compression. The treatment was well tolerated for 4.5 years and tumor volume has remained unchanged after a 20-fold reduction compared with the size prior to treatment. The patient has remained symptom-free. DISCUSSION: In this critical clinical situation, tamoxifen provided rapid and prolonged effect and was well tolerated.     

The complete mitochondrial DNA sequence of the pig (Sus scrofa)

Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary disorder caused by a germline inactivating mutation of the adenomatous polyposis coli (APC) gene. Patients with FAP sometimes develop various extracolonic manifestations including adrenocortical neoplasms. We present a 14-year-old boy with FAP who had an adrenocortical tumor with atypical histopathologic features, ie, sex-cord-like differentiation. Immunohistochemical studies of adrenal 4 binding protein (Ad4BP) and steroidogenic enzymes showed the capacity of these tumor cells to produce steroids. Genetic analysis of the tumor disclosed a two-hit mutation in APC: a germline 5-base pair deletion accompanied by a loss of the normal allele. Because there were no reports of genetic alterations in adrenocortical tumors developed in FAP patients, we examined 10 sporadic adrenal tumors (four carcinomas and six adenomas) for mutations in APC. However, no mutations were found in these 10 sporadic adrenal tumors. These results suggest that mutation of APC is also responsible for some fraction of the adrenocortical tumors: the tumor in this case is included.     

Presymptomatic diagnosis of familial colon polyposis

The gene responsible for familial adenomatous polyposis (FAP) has recently been mapped, identified and this makes the presymptomatic molecular diagnosis of the disease possible. It can be performed by direct mutation analysis or indirect haplotype analysis. In families where several affected individuals are available the indirect haplotype analysis is the easiest way for performing presymptomatic diagnosis of persons at risk. Among Hungarian families we have performed haplotype analysis using D5S346, a highly polymorphic dinucleotide CA repeat marker located 30-70 kb downstream from APC gene with the combination of restriction endonuclease Rsal site polymorphism. Marker regions were amplified by polymerase chain reaction (PCR) and basen on the above-mentioned polymorphic systems, the haplotype at the APC locus was determined. We believe that haplotype analysis of individuals at risk in large FAP families containing several affected members is a rapid, efficient, and highly valuable method for presymptomatic diagnosis of familial colon polyposis.     

No evidence for overexpression of the p53 protein and mutations in exons 4-9 of the p53 gene in a large family with adenomatous polyposis

OBJECTIVE: Familial adenomatous polyposis coli (FAP) is an autosomal dominant disease characterized by an early onset of numerous adenomatous polyps of the colon and a high risk of colon carcinoma. The role of the p53 gene in the multistage process of FAP is as yet poorly defined. In the present study, a large family with evidence of polyposis and colon cancer was screened for the mutations of the p53 gene and protein overexpression. METHODS: We examined p53 protein expression from individuals with immunohistochemical techniques using monoclonal antibody PAb1801. Polymerase chain reaction products of exons 4-9 of the p53 were examined from individuals by single strand, conformational polymorphism analysis. RESULTS: We could find no evidence of overexpression and mutations of the p53 in any lesion including adenomas and carcinomas. CONCLUSION: We found that p53 gene alterations do not contribute to the genesis of adenoma or carcinoma of FAP patients for this large family examined.     

Loss of the PLA2G2A gene in a sporadic colorectal tumor of a patient with a PLA2G2A germline mutation and absence of PLA2G2A germline alterations in patients with FAP

The Min (multiple intestinal neoplasia) mouse with a germline mutation in the adenomatous polyposis coli gene serves as an animal model for familial adenomatous polyposis coli (FAP). The number and age at onset of colorectal adenomas varies in the offspring of Min mice crossed with other strains. The murine gene for the secretory phospholipase A2 (PLA2G2A) was found to be the main candidate for these variations. To test the hypothesis of a correlation between PLA2G2A gene alterations and human tumor development, we screened 14 patients with FAP and 20 patients with sporadic colorectal cancer for germline and somatic PLA2G2A gene mutations. None of the individuals with FAP showed PLA2G2A germline alterations. However, a germline mutation was observed in one patient with an apparently sporadic colorectal tumor; the wildtype allele was somatically lost in the tumor of this patient.     

Anticipatory nausea and vomiting in the era of 5-HT3 antiemetics

Variegate porphyria (VP) is an autosomal dominant disorder characterised by a partial defect in the activity of protoporphyrinogen oxidase (PPO), and has recently been genetically linked to the PPO gene on chromosome 1q22-23 (Z=6.62). In this study, we identified a mutation in the PPO gene in a patient with VP and two unaffected family members. The mutation consisted of a previously unreported T to C transition in exon 13 of the PPO gene, resulting in the substitution of a polar serine by a non-polar proline (S450P). This serine residue is evolutionarily highly conserved in man, mouse, and Bacillus subtilis, attesting to the importance of this residue. Interestingly, the gene for Gardner's syndrome (FAP) also segregates in this family, independently of the VP mutation. Gardner's syndrome or familial adenomatous polyposis (FAP) is also an autosomal dominantly inherited genodermatosis, and typically presents with colorectal cancer in early adult life secondary to extensive adenomatous polyps of the colon. The specific gene on chromosome 5 that is the site of the mutation in this disorder is known as APC (adenomatous polyposis coli), and the gene has been genetically linked to the region of 5q22.     

Current data on the role of APC protein in the origin of colorectal cancer

The adenomatous polyposis coli (APC) gene has been found to be mutated during the development of sporadic colorectal cancers as well as in familial adenomatous polyposis (FAP). These conditions result from initially somatic and germ line mutations respectively. In both cases, the expressed protein is truncated at its carboxyterminal region. Investigations into the role of wild-type APC have led to a better understanding of the importance of mutations in the genesis and progression of adenomas. APC was shown to regulate cell growth and cell death, to bind beta-catenin, and to colocalize with microtubules. APC truncation was therefore hypothesized to alter cell multiplication and cells are no longer able to undergo apoptosis. Owing to its beta-catenin binding, APC can modify the pool of beta-catenin which is in part utilized in the assembly of adherens junctions and in nuclear signalling. Truncated APC is unable to regulate this pool thereby altering adhesion and cell signalling. Finally, APC involvement in microtubule-dependent locomotion may explain some changes in cell movement which are observed in adenomas. The establishment of murine mutants and of normal and malignant intestinal cell cultures have allowed to assess biochemical and physiological properties of APC and its putative role in the genesis of colorectal carcinogenesis. Moreover, these experimental models have suggested a variety of possible therapeutic approaches.