APC or MUTYH mutations account for the majority of clinically well-characterized families with FAP and AFAP phenotype and patients with more than 30 adenomas.

Patients presenting familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP) or multiple colorectal adenomas (MCRAs) phenotype are clinically difficult to distinguish. We aimed to genetically characterize 107 clinically well-characterized patients with FAP-like phenotype, and stratified according to the recent guidelines for the clinical management of FAP: FAP, AFAP, MCRA (10-99 colorectal adenomas) without family history of colorectal cancer or few adenomas (FH), MCRA (10-99) with FH, MCRA (3-9) with FH. Overall, APC or MUTYH mutations were detected in 42/48 (88%), 14/20 (70%) and 10/38 (26%) of FAP, AFAP and MCRA patients, respectively. APC and MUTYH mutations accounted for 81% and 7% of FAP patients and for 30% and 40% of AFAP patients, respectively. Notably, MCRA patients did not present APC mutations. In 26% of these patients, an MUTYH mutation was identified and the detection rate increased with the number of adenomas, irrespectively of family history, being significantly higher in MCRA patients presenting more than 30 adenomas [7/12 (58%) vs 2/14 (14%), p = 0.023]. We validate the recently proposed guidelines in our patient's cohort and show that APC or MUTYH germline defects are responsible for the majority of clinically well-characterized patients with FAP and AFAP phenotype, and patients with more than 30 colorectal adenomas. The different mutation frequencies according to family history and to the number of adenomas underscore the importance of an adequate familial characterization, both clinically and by colonoscopy, in the management of FAP-like phenotypes. The phenotypes of the mutation-negative patients suggest distinct etiologies in these cases.

[Familial colorectal cancer type X: clinical, pathological and molecular characterization]. / Carcinoma colorectal familiar de tipo X: caracterização clínica, patológica e molecular.

BACKGROUND: Some families fulfilling the Amsterdam Criteria (AC) differ from the Lynch syndrome (LS) in that colorectal cancers (CRC) do not present microsatellite instability (MSI) and DNA mismatch repair gene mutations are not found. These families have been designated as Familial Colorectal Cancer type X (XS) and their genetic basis remains unknown. AIMS: In families fulfilling AC for LS: 1) To perform MSI testing in CRC and to correlate it with clinical and pathological characteristics and with the mutational analysis in the DNA mismatch repair genes; 2) In cases suggestive of XS, to study the suppressor pathway (SP) of carcinogenesis. PATIENTS AND METHODS: 45 patients with CRC, from 41 families fulfilling AC, were included. Clinical and pathological data were recorded. MSI testing was performed with the Bethesda marker panel and mutational analysis in MLH1, MSH2 and MSH6 genes was undertaken by DGGE, MLPA and direct sequencing. To study the SP, loss of heterozigoty was evaluated at the following loci: APC, p53, DCC and SMAD4 genes. RESULTS: 33/41 (80%) and 8/41 (20%) families presented high-grade microsatellite instability (MSI-H) and microsatellite stable (MSS) CRC, respectively. In families suggestive of XS, a smaller number of CRC and less frequent spectrum associated tumors were detected. In comparison with MSI-H CRC, MSS CRC were preferentially located at the distal colon/rectum and less often presented mucous production or lymphocytic infiltrate. In 70% of families with MSI-H CRC, a pathogenic mutation in one of the DNA mismatch repair genes was identified, as opposed to none in the group with MSS CRC. The SP was followed in 2 cases and an alternative one in other two. The remaining 4 cases were noninformative; however, 5/8 (63%) presented allelic losses in the APC gene. CONCLUSIONS: 1) Families fulfilling AC and harbouring MSS CRC presented particular characteristics, which reinforce the existence of a new entity, different from LS; 2) The designation of Familial Colorectal Cancer type X seems appropriate to classify an entity whose CRC follow an unclear carcinogenesis pathway and that presents an unknown genetic basis; 3) The designation of LS should be restricted to families with an identified pathogenic DNA mismatch repair gene mutation.

[Dysphagia and dysarthria: unusual presentation of Myasthenia Gravis]. / Disfagia e disartria: forma invulgar de apresentação da Miastenia Gravis.

Myasthenia Gravis is an autoimmune disorder that generally presents with ocular symptoms, specially diplopia and ptosis. Dysphagia may be a manifestation of the generalised type of the disease, but rarely is its presenting feature. The authors describe a case of Myasthenia Gravis in an old patient complaining of dysphagia and dysarthria. Because Myasthenia Gravis is a potentially serious but treatable disease, we emphasize the need to consider it in the differential diagnosis of dysphagia, namely in the elderly. In fact, the disorder is probably underdiagnosed in this population group, because clinicians tend to accept other more frequent diagnosis to explain these symptoms.

Schwannoma of the esophagus: computed tomography and endosonographic findings of a special type of schwannoma.

Schwannomas of the digestive tract are uncommon benign tumors seldom located in the esophagus. We present a case of intramural esophageal schwannoma with histopathological correlation evaluated by computed tomography and endoscopic ultrasonography. The imaging findings are described and other relevant features of schwannomas of the esophagus are discussed.

Management of Portuguese patients with hyperplastic polyposis and screening of at-risk first-degree relatives: a contribution for future guidelines based on a clinical study.

BACKGROUND: Hyperplastic polyposis (HP) is a rare condition characterized by the presence of multiple hyperplastic polyps in the colon, which has been associated to an increased risk of colorectal cancer (CRC). Guidelines for management of this disease remain, so far, undefined. AIMS: To evaluate, in symptomatic patients with HP, phenotypic characteristics as well as results of a screening program in their at-risk first-degree relatives. PATIENTS: Pedigree information and clinical and endoscopic data of 14 patients with HP was studied. SEVENTEEN AND METHODS: at-risk first-degree relatives from six families were also invited to perform screening colonoscopy. RESULTS: Twelve of fourteen (86%) patients had fewer than 100 colorectal polyps. Polyps' sizes ranged from 2 to 25 mm and were uniformly distributed through the whole colon in 43% of the patients. Hyperplastic polyps predominated, but 11/14 (79%) patients also harbored serrated as well as classic adenomatous polyps. CRC was present in 6/14 (43%) of the patients at the time of diagnosis. Familial history of CRC/polyps was positive in 6/12 (50%) of cases. Colonoscopy in at-risk relatives disclosed polyps in 10/17 (59%) of cases with at least one additional patient having criteria for HP. CONCLUSIONS: Although small, this series demonstrates that a high level of suspicion is needed to diagnose the HP syndrome, in which serrated adenomas seem to be the hallmark. Although an elevated percentage of CRC was observed in this series of symptomatic patients with HP, prospective studies in asymptomatic individuals are needed to clearly quantify the risk of CRC in patients with HP. Because familial aggregation of HP was present in 3/12 (25%) of kindreds, screening colonoscopy should be offered to first-degree relatives.

Adenocarcinoma of the esophagogastric junction: could the characteristics of adjacent intestinal metaplasia help in the understanding of biopathogenesis?

We report a case of early adenocarcinoma arising in foci of intestinal metaplasia (IM) at a normal-appearing gastroesophageal junction (GEJ). The tumor infiltrated the submucosa without nodal involvement (T1N0). Non-neoplastic mucosa adjacent to neoplasia had foci of incomplete IM with a band-like CK20 positivity of the surface epithelium and a diffuse CK7 staining of both superficial and deep glands. There were histological features of reflux esophagitis as well as chronic non-atrophic, Helicobacter pylori-related pangastritis, without IM, at the extensively assessed gastric mucosa. In this case, the CK7/20 pattern of IM adjacent to neoplasia, the demonstration of reflux esophagitis, and the absence of IM in the stomach favor the theory that the pathogenesis of IM and associated adenocarcinoma of the GEJ is related to gastroesophageal reflux rather than H. pylori infection.

Pathogenicity of missense and splice site mutations in hMSH2 and hMLH1 mismatch repair genes: implications for genetic testing.

BACKGROUND: In hereditary non-polyposis colorectal cancer, over 90% of the identified mutations are in two genes, hMSH2 and hMLH1. A large proportion of the mutations detected in these genes are of the missense type which may be either deleterious mutations or harmless polymorphisms. AIM: To investigate whether nine missense and one splice site mutation of hMLH1 and hMSH2, in 10 kindreds with a familial history of colorectal cancer or young age of onset, could be interpreted as pathogenic. METHODS: Clinical and genetic characteristics were collected: (i) evolutionary conservation of the codon involved; (ii) type of amino acid change; (iii) occurrence of mutation in healthy controls; (iv) cosegregation of mutation with disease phenotype; (v) functional consequences of gene variant; and (vi) microssatellite instability and immunoexpression of hMSH2 and hMLH1 analysis. RESULTS: Seven different missense and one splice site mutation were identified. Only 1/8 was found in the control group, 2/7 occurred in conserved residues, and 5/7 resulted in non-conservative changes. Functional studies were available for only 2/8 mutations. Segregation of the missense variant with disease phenotype was observed in three kindreds. CONCLUSION: In the majority of families included, there was no definitive evidence that the missense or splice site alterations were causally associated with an increased risk of developing colorectal cancer. Until further evidence is available, these mutational events should be regarded and interpreted carefully and genetic diagnosis should not be offered to these kindreds.

BAT-26 identifies sporadic colorectal cancers with mutator phenotype: a correlative study with clinico-pathological features and mutations in mismatch repair genes.

Microsatellite instability (MSI) is present in most colorectal cancers (CRC) associated with hereditary nonpolyposis colorectal cancer (HNPCC). MSI testing in so-called sporadic forms of CRC may become a useful tool in identifying new HNPCC kindred. The aim of this study was to analyse the utility of BAT-26 as a marker to identify CRCs with MSI and to investigate whether sporadic CRCs with MSI have a phenotypic expression similar to HNPCC cases. MSI was detected using two methods, an association of 7 poly(CA) repeats and a poly(A) repeat alone, BAT-26, in a series of 62 patients with apparently sporadic forms of CRC. Germ-line and somatic mutations in the hMSH2, hMLH1, and hMSH6 genes were analysed in patients with MSI+ tumours. Patients with MSI+ at poly(CA) loci and at BAT-26 were younger (p=0.024 and p=0.002), had tumours more frequently right sided (p=0.017 and p=0.0001) and more often mucinous (p=0.037 and p=0.005, respectively) than patients with MSI negative tumours. Mutation analysis allowed the identification of two patients carrying germ-line mutations in the hMLH1 gene (both were BAT-26+) and two other patients who had somatic mutation in the hMSH2 and in hMLH1 genes. In conclusion, the detection of MSI using poly(CA) repeats or BAT-26 alone allowed the identification of a subset of patients with clinico-pathological characteristics similar to those associated to HNPCC. BAT-26 has the advantage of being a simple and less expensive method that might be used as a screening procedure before mutation analysis.

Seven novel mutations in the APC gene of Portuguese families with familial adenomatous polyposis: correlation with phenotype.

Germ-line mutations in the adenomatous polyposis coli (APC) gene are responsible for familial adenomatous polyposis (FAP). In the present study, we have used the protein truncation test to screen for mutations in exon 15 and exons 1-14 of the APC gene and denaturing gradient gel electrophoresis to analyze exons 1-14. We have studied nine unrelated FAP kindreds, eight with the classical phenotype and one with an atypical phenotype, with several family members exhibiting fewer than 50 colonic polyps. The combined use of these two methodologies allowed the identification of seven novel mutations, with two unrelated families sharing the same mutation. All mutations were chain terminating: six resulted from small deletions, one from a small insertion, and one was a point mutation, resulting in a premature stop codon. Seven mutations were located in exon 15 of the APC gene, one was in exon 10, and the remaining one, which corresponded to the kindred with an atypical phenotype, was located in exon 4.

Validation and simplification of Bethesda guidelines for identifying apparently sporadic forms of colorectal carcinoma with microsatellite instability.

BACKGROUND: Colorectal tumors with microsatellite instability (MSI) that do not comply with previously defined clinical criteria may be found in recently diagnosed hereditary nonpolyposis colorectal carcinoma families. Until recently, the indications for MSI testing were not clearly established. The objective of the current study was to validate the recently published Bethesda guidelines for MSI testing in a series of patients with apparently sporadic forms of colorectal carcinoma (CRC). METHODS: Sixty-two patients with so-called sporadic CRC were included in the current study. MSI was analyzed at seven poly(CA) repeat sequences and at one poly(A) locus. RESULTS: Nine of 62 patients (14.5%) had tumors exhibiting MSI at > or = 2 loci and 7 patients (11%) had MSI at > or = 3 loci. Patients with MSI positive tumors were younger (P < 0.05), and their tumors more frequently were right-sided (P < 0.02) and more often exhibited a mucinous component (P < 0.05). The Bethesda guidelines were positive in 18% (11 of 62) of patients. The sensitivity of these guidelines in identifying tumors with MSI at > or = 3 loci was 43% and the positive predictive value (PPV) was 27% (3 of 11 cases). Other variables were considered as alternative criteria to identify CRCs with MSI: age < 45 years and/or a right-sided tumor with a mucinous component. Using these 2 criteria alone, sensitivity increased to 85% and PPV to 46%. CONCLUSIONS: In this study group, the use of three clinical criteria as sole indicators for MSI testing in patients with apparently sporadic forms of CRC were significantly more discriminating compared with the Bethesda guidelines, in addition to being substantially easier.

Microsatellite instability in non-neoplastic mucosa of patients with ulcerative colitis: effect of folate supplementation.

OBJECTIVE: Microsatellite instability (MSI) detected in non-neoplastic mucosa of patients with ulcerative colitis has been ascribed to an excess of DNA damage associated with chronic inflammation. Folate deficiency, commonly found in patients with long-standing disease, could further contribute to this defect because folate is essential for DNA replication and repair. We evaluated MSI in the colonic mucosa of 26 patients with ulcerative colitis for >10 yr and 10 patients with Crohn's colitis and correlated MSI with folate status. METHODS: DNA was amplified using primers directed at nine different loci. Folate concentrations in serum, whole blood, and colonic mucosa were determined using the Lactobacillus casei assay. RESULTS: MSI was found in 3/23 patients (13%) with ulcerative colitis and in none of the patients with Crohn's colitis. All three patients with MSI had inactive histological disease, whereas all patients with active disease were negative for MSI (p = 0.08). Serum, whole blood, and colonic concentrations of folate were 30-50% lower in patients with MSI (p > 0.05), and folate supplements had been administered less frequently during the past 5-yr (p = 0.06). One of the patients with MSI was randomized to receive folate 5 mg/d for 6 months, and a clear change in MSI pattern was observed in three of six markers. CONCLUSIONS: A defect in DNA repair associated with a low folate status may be one additional cause for patients with ulcerative colitis exhibiting MSI in non-neoplastic mucosa.

Colonic cancer in a 34-yr-old woman: should it prompt microsatellite instability studies and mismatch repair gene testing?

It remains debatable whether young patients with colorectal tumors should undergo genetic testing with the aim of identifying new hereditary nonpolyposis colorectal cancer families. We describe a case of a young woman with colon cancer with no clinical criteria of hereditary nonpolyposis colorectal cancer, whose genetic analysis showed that the tumor displayed microsatellite instability, and in whom a truncated protein in hMSH2 gene was found, which was also present in two at-risk relatives.

Treatment of gastric MALT lymphoma by Helicobacter pylori eradication: a study controlled by endoscopic ultrasonography.

OBJECTIVE: Previous studies have demonstrated a link between Helicobacter pylori infection and low grade B-cell gastric MALT lymphoma. The aim of this study was to evaluate the effect of Helicobacter pylori eradication in 17 patients with low grade B-cell gastric MALT lymphoma stage EI. METHODS: For disease staging EUS and CT scan were systematically performed. Eight patients were excluded from the present series because stage EII disease was diagnosed. To demonstrate B-cell monoclonality, immunohistochemistry and polymerase chain reaction were used. H. pylori eradication was performed with triple therapy. RESULTS: H. pylori was eradicated in all patients after first (n = 15) or second line (n = 2) treatment. Histologic regression of lymphoma was observed in all patients after a median period of 2 mo. Disappearance of monoclonality according to polymerase chain reaction took significantly longer (7 mo). At the end of the study, four of 16 patients still exhibited persistent monoclonal bands. Relapse of lymphoma occurred in two patients associated with H. pylori reinfection/recrudescence. CONCLUSION: Eradication of H. pylori seems to be an effective therapy in patients with stage EI gastric MALT lymphoma, although long-term results are still uncertain. Endoscopic ultrasonography is useful for a more accurate staging of the disease. The clinical significance of detecting monoclonality by polymerase chain reaction remains to be determined.

Effect of folate supplementation on DNA methylation of rectal mucosa in patients with colonic adenomas: correlation with nutrient intake.

We have evaluated the effect of folate supplementation (5 mg/day) on global deoxyribonucleic acid (DNA) methylation status of the rectal mucosa of 20 patients with resected colonic adenomas in a prospective, controlled, cross-over study. Baseline values of DNA methylation were inversely correlated with caloric (P = 0.03) and fat intake (P = 0.05) and patients harbouring multiple polyps consumed significantly more calories (P = 0.0006), fat (P = 0.009) and carbohydrates (P = 0.009) as compared to patients having one single lesion. Folate supplementation resulted in a significant decrease of DNA hypomethylation in 7/20 patients (P = 0.05) which returned to previous values after placebo treatment. This effect was significantly correlated with number of polyps, with all the responders presenting one single lesion, whereas 8/13 of the non-responders had multiple ones (chi2 = 7.17, P = 0.007). In conclusion, folate supplementation may decrease degree of DNA hypomethylation, but only in patients with one single polyp. In those with multiple lesions, other nutritional factors such as caloric and fat intake, may be more determinant.

Global DNA hypomethylation occurs in the early stages of intestinal type gastric carcinoma.

BACKGROUND: Global DNA hypomethylation has been found in the premalignant stages of some neoplasms and has been implicated as an important factor for tumour progression. AIMS: The aim of this study was to evaluate whether DNA hypomethylation occurs during the process of gastric carcinogenesis. METHODS: Gastric specimens were obtained from 49 patients and histologically classified as: normal 10, superficial gastritis 14, chronic atrophic gastritis with intestinal metaplasia 15, and intestinal type of gastric carcinoma 10. Global DNA methylation was assessed by incubating DNA with (3H)-S-adenosylmethionine and Sss1 methylase. A higher incorporation of (3H) methyl groups reflects a lower degree of intrinsic methylation. RESULTS: A graduated increase in (3H) methyl group incorporation into DNA was found over the range extending from normal gastric mucosa, to superficial gastritis and to chronic atrophic gastritis (136,556 (24,085) v 235,725 (38,636) v 400,998 (26,747 dpm/micrograms/DNA respectively; p = 0.0002). No further increase was found in specimens from patients with carcinoma. No differences were found between extent of DNA methylation in neoplastic or non-neoplastic mucosa from patients with gastric carcinoma. Hypomethylation of DNA increased substantially with severe atrophy (p = 0.01) or with type III intestinal metaplasia (p = 0.15). CONCLUSIONS: Global DNA hypomethylation occurs in the early stages of gastric carcinogenesis, and it may be a novel biomarker of gastric neoplasia, useful in monitoring the response to chemopreventive agents.

Calcium regulation of colonic crypt cell kinetics: evidence for a direct effect in mice.

BACKGROUND & AIMS: Oral calcium supplementation is believed to decrease colonic hyperproliferation through neutralization of fatty acids and bile acids. In the present study, the effect of oral calcium, given with low-fat diets, in the early stages of colorectal carcinogenesis is evaluated. METHODS: In experiment A, mice received normal or low-calcium diets and were killed at 25 weeks. In experiment B, mice were fed the same diets but were submitted to six weekly injections of dimethylhydrazine and were killed at 10, 16, and 21 weeks. Cell proliferation was evaluated using bromodeoxyuridine immunohistochemistry. RESULTS: In experiment A, mice fed low-calcium diets showed a significant upward shift of the proliferative compartment (P = 0.04) (phase 2 defect) in the absence of hyperproliferation. In experiment B, besides a phase 2 defect, dimethylhydrazine-induced hyperproliferation was also significantly enhanced in animals fed low-calcium diets (phase 1 defect) as shown by an increased number of labeled cells per column and total labeling index (P = 0.01). CONCLUSIONS: Low-calcium diets induce an upward shift of the main proliferative compartment, which reflects an increased risk for malignant transformation. This effect was observed with a low-fat diet, suggesting a direct mechanism, rather than the usual indirect one, documented with high-fat diets.

Early gastric cancer: an analysis of 44 cases with emphasis on the prognostic significance of the macroscopic and microscopic growth patterns.

Forty-four consecutive cases of "early gastric cancer" were studied according to the macroscopic classification proposed by the Japanese Gastroenterological and Endoscopy Society and further analyzed in terms of growth patterns. The tumours were then classified into the small mucosal type, the superficially spreading (Super) type and the penetrating growth (Pen) type. The Lauren type (intestinal vs. diffuse), presence of lymphatic and venous invasion, and lymph node metastasis were also assessed. Most elevated tumours showed a superficial growth pattern and were classified as Lauren's intestinal type, whereas depressed lesions were associated with submucosal invasion and were classified as diffuse. Microscopic patterns did not show any correlation with Lauren's classification. Mean duration of follow-up was 67.8 months and the overall actuarial survival was 93%, 80%, and 72%, at 2, 5, and 10 years, respectively. Aside from venous invasion no correlation was found between survival and any of the morphological parameters analysed.