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EPHB2 germline variants in patients with colorectal cancer or hyperplastic polyposis.

BACKGROUND: Ephrin receptor B2 (EPHB2) has recently been proposed as a novel tumor suppressor gene in colorectal cancer (CRC). Inactivation of the gene has been shown to correlate with progression of colorectal tumorigenesis, and somatic mutations have been reported in both colorectal and prostate tumors. METHODS: Here we have analyzed the EPHB2 gene for germline alterations in 101 individuals either with 1) CRC and a personal or family history of prostate cancer (PC), or 2) intestinal hyperplastic polyposis (HPP), a condition associated with malignant degeneration such as serrated adenoma and CRC. RESULTS: Four previously unknown missense alterations were observed, which may be associated with the disease phenotype. Two of the changes, I361V and R568W, were identified in Finnish CRC patients, but not in over 300 Finnish familial CRC or PC patients or more than 200 population-matched healthy controls. The third change, D861N, was observed in a UK HPP patient, but not in additional 40 UK HPP patients or in 200 UK healthy controls. The fourth change R80H, originally identified in a Finnish CRC patient, was also found in 1/106 familial CRC patients and in 9/281 healthy controls and is likely to be a neutral polymorphism. CONCLUSION: We detected novel germline EPHB2 alterations in patients with colorectal tumors. The results suggest a limited role for these EPHB2 variants in colon tumor predisposition. Further studies including functional analyses are needed to confirm this.

Adolescent↗

Histochemistry of small intestinal dysplasia in familial polyposis coli.

Biopsies of duodenal and ileal mucosa from patients with familial polyposis coli were studied. Areas of atypia were identified in the duodenum of six patients and in the ileum of three patients. Grade I atypia was characterized by crowding and elongation of cells and nuclei, a slight reduction in the number of goblet cells and the presence of a brush border; grade II atypia was further characterized by pseudo- or pluristratification of cells, a marked reduction in the number of goblet cells and the absence of a brush border. In areas of atypia, columnar cells often contained PAS-positive apical granules, which were diastase-resistant and unstained by alcian blue at any pH; the brush border, even where recognizable in haematoxylin-eosin and PAS-stained sections, was unreactive histochemically for alkaline phosphatase. Goblet cells were few in areas of atypia, but those present were regularly stained by PAS and alcian blue pH 2.6. Apical granules, similar in their histochemical characteristics to those observed in columnar cells in areas of atypia, were also found in otherwise normal mucosal areas, even in some patients with no overt areas of atypia in the biopsies studied. These granules have been interpreted as an abnormality, possibly preceding the onset of atypia. Hyperplasia of goblet cells, secreting mucins with the same staining pattern as in normal intestine, was found in some patients, either adjacent to areas of atypia or independent of them. Intervening columnar cells had a normal morphology, alkaline phosphatase-reactive brush borders and no sign of mucus secretion. This goblet cell hyperplasia has been interpreted as a reactive, nonspecific alteration of the mucosa.

Adenomatous Polyposis Coli↗

BRAF mutations in aberrant crypt foci and hyperplastic polyposis.

Patients with hyperplastic polyposis have multiple hyperplastic polyps (HPs) and increased risk of colorectal carcinomas. Aberrant crypt foci (ACF) are postulated to be the earliest precursor lesions in colorectal carcinogenesis. We evaluated BRAF mutations by DNA sequencing in 53 ACF from patients with sporadic colorectal carcinomas and familial adenomatous polyposis, in 18 sporadic HPs from patients with resected colorectal cancer, and in 70 HPs, 4 serrated adenomas, 3 admixed hyperplastic-adenomatous polyps, 10 tubular adenomas, and 6 carcinomas from 17 patients with multiple/large HPs and/or hyperplastic polyposis. BRAF mutation status was compared with clinicopathological features and other genetic alterations by marginal logistic regression. BRAF mutation was present in only 2% of ACF and 6% of sporadic HPs. In contrast, BRAF mutation was present in 43% of HPs (P = 0.01 versus sporadic HPs), 75% of serrated adenomas, 33% of admixed hyperplastic-adenomatous polyps, 30% of tubular adenomas, and 33% of carcinomas from patients with multiple/large HPs and/or hyperplastic polyposis. BRAF mutation status in patients with multiple/large HPs and/or hyperplastic polyposis correlated with HPs from the same patient (odds ratio, 5.8; P = 0.0002) but associated with younger age (odds ratio, 0.83; P = 0.006 compared to older age), with a large HP (odds ratio, 22.5; P = 0.01 compared with patients with multiple HPs), with location of HPs in the right colon (odds ratio, 3.0; P = 0.03), and with methylation of the p16 gene and the MINT31 locus [odds ratio, 12.2 (P = 0.0001) and 4.4 (P = 0.02), respectively]. Our study shows that BRAF mutation status is heterogeneous among patients with multiple/large HPs and/or hyperplastic polyposis, suggesting differences in pathogenesis of HPs that indicate subsets within this phenotype.

Adenocarcinoma↗

The possible presence of a separate disease entity in nonfamilial polyposis of the large intestine.

Familial adenomatosis coli (FAC) traditionally has been diagnosed as the presence of more than 100 colonic adenomas, even if no familial occurrence is present. In the present communication, clinical features of FAC have been compared in detail to detect differences between familial and nonfamilial cases with regard to colonic and extracolonic lesions and to discover whether they constitute the same disease entities. No significant difference was found in the incidence of extracolonic lesions. The average number of colonic polyps in the nonfamilial cases of patients over 30 years old was 1128, the number of polyps was significantly higher in the familial cases (3154). When three patients with approximately 100 polyps were excluded, the mean number of colonic polyps in nonfamilial cases became 2608. This was similar to that of familial cases. Furthermore, the occurrence of approximately 100 polyps was extremely rare in familial patients who were over 30 years old. Therefore, most of the nonfamilial cases can be considered to be familial probands of FAC, but some, such as the three cases in the present study, may be a different disease entity, such as recessive adenomatous polyposis or multiple colonic adenomas.

Adenoma↗

Molecular classification of patients with unexplained hamartomatous and hyperplastic polyposis.

CONTEXT: Significant proportions of patients with hamartomatous polyposis or with hyperplastic/mixed polyposis remain without specific clinical and molecular diagnosis or present atypically. Assigning a syndromic diagnosis is important because it guides management, especially surveillance and prophylactic surgery. OBJECTIVE: To systematically classify patients with unexplained hamartomatous or hyperplastic/mixed polyposis by extensive molecular analysis in the context of central rereview of histopathology results. DESIGN, SETTING, AND PATIENTS: Prospective, referral-based study of 49 unrelated patients from outside institutions (n = 28) and at a comprehensive cancer center (n = 21), conducted from May 2, 2002, until December 15, 2004. Germline analysis of PTEN, BMPR1A, STK11 (sequence, deletion), SMAD4, and ENG (sequence), specific exon screening of BRAF, MYH, and BHD, and rereview of polyp histology results were performed. MAIN OUTCOME MEASURES: Molecular, clinical, and histopathological findings in patients with unexplained polyposis. RESULTS: Of the 49 patients, 11 (22%) had germline mutations. Of 14 patients with juvenile polyposis, 2 with early-onset disease had mutations in ENG, encoding endoglin, previously only associated with hereditary hemorrhagic telangiectasia; 1 had hemizygous deletion encompassing PTEN and BMPR1A; and 1 had an SMAD4 mutation. One individual previously classified with Peutz-Jeghers syndrome had a PTEN deletion. Among 9 individuals with an unknown hamartomatous polyposis, 4 had mutations in STK11 (1), BMPR1A (2), and SMAD4 (1). Of the 23 patients with hyperplastic/mixed polyposis, 2 had PTEN mutations. Substantial discrepancies in histopathology results were seen. CONCLUSIONS: Systematic molecular classification of 49 patients with unexplained hamartomatous or hyperplastic polyposis uncovered a potential novel susceptibility gene, ENG, for juvenile polyposis. Importantly, given the substantial proportion of patients found to have germline mutations, more extensive analysis of the known susceptibility genes is indicated. Rereview of histology results by a dedicated gastrointestinal pathologist should be considered routinely, as organ-specific surveillance rests on defining syndromic diagnosis.

AMP-Activated Protein Kinase Kinases↗

Background mucosal changes of primary advanced large intestinal cancer in patients without familial polyposis coli.

In 337 cases of primary advanced large intestinal cancer in patients without familial polyposis coli, the risk factor for cancer was discussed chiefly from the background mucosa surrounding and apart from the cancers. The following findings were obtained: (1) in the mucosa surrounding cancers, adenoma was seen in 23 cases (6.8 per cent), adenomatous changes of the basal cells in 211 cases (62.6 per cent), and hyperplastic glands in 167 cases (49.6 per cent), (2) in the mucosa at least 10 mm from the cancers, adenoma, adenomatous changes of the basal cells, and hyperplastic glands were seen in 42 cases (12.5 per cent), 129 cases (38.3 per cent), and 40 cases (11.9 per cent), respectively. Therefore, it is suggested that microscopic adenoma and adenomatous changes of the basal cells might be a sign of premalignancy in patients without familial polyposis coli.

Adenocarcinoma↗

[Coloscopic characterization of polyposis of the large intestine. Macroscopic aspects and histological correlations].

On the basis of the usual macroscopic pathological descriptions, the possibility of characterizing endoscopically the various types of polypous proliferations in the large intestine is examined. The endoscopic parameters considered are described together with the histopathological findings incases of polyps observed over a period of 6 months. Comparison between presumed diagnosis formulated at coloscopic examination and final histological diagnosis shows a concordance of 80%. The usefulness of being able to give some indication regarding the type of nature of the polyps as early as endoscopy is stressed.

Biopsy↗