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Background: CDC4/FBXW7, encoding a ubiquitin ligase, maps to 4q32 and has been implicated as a tumor suppressor gene and therapeutic target in many tumor types. Mutations in colonic adenomas, and the frequent losses on 4q described in gastric cancer prompt speculation about the role of CDC4/FBXW7 in gastric carcinogenesis.Methods: We assessed the role of CDC4/FBXW7 in gastric cancer, through loss of heterozygosity (LOH) and multiplex ligation-dependent probe amplification (MLPA) on 47 flow-sorted gastric carcinomas including early-onset gastric cancers (EOGC) and xenografted conventional gastric carcinomas. Ploidy analysis was carried out on 39 EOGCs and immunohistochemistry of CDC4/FBXW7 and its substrates c-myc, c-jun, Notch and cyclin E was performed on 204 gastric carcinomas using tissue microarrays (TMAs). Sequence analysis of CDC4/FBXW7 was carried out on gastric carcinoma cell lines and xenografts.Results: Loss of heterozygosity of CDC4/FBXW7 occurred in 32% of EOGCs, and correlated with loss of expression in 26%. Loss of expression was frequent in both EOGC and conventional gastric cancers. No CDC4/FBXW7 mutations were found and loss of CDC4/FBXW7 did not correlate with ploidy status. There was a significant correlation between loss of CDC4/FBXW7 expression and upregulation of c-myc.Conclusion: Loss of CDC4/FBXW7 appears to play a role in both EOGC and conventional gastric carcinogenesis, and c-myc overexpression is likely to be an important oncogenic consequence of CDC4/FBXW7 loss.

Background: K-ras mutations in endobiliary brush cytology are an early event in carcinogenesis and justify a suspicion of malignancy in patients with extrahepatic biliary stenosis. However, K-ras mutations have been detected in specimens obtained by brushing of clinically benign extrahepatic biliary stenosis. The aim of this study was to determine whether these findings represent an early or false-positive diagnosis of cancer. Methods: Cytologic specimens were obtained by brushing in 312 consecutive patients with extrahepatic biliary stenosis. Mutations in the K-ras oncogene were detected by an enriched polymerase chain reaction and allele-specific oligonucleotide hybridization assay. Eight patients with a K-ras mutation and a clinically benign extrahepatic biliary stenosis were followed. Results: After a median follow-up of 65 months, 6 of the 8 patients were alive without evidence of malignancy. One patient died of congestive heart failure. The other patient died 60 months after the specimen was obtained, possibly because of chronic pancreatitis, although previously there had been suspicion of malignancy. Biopsy specimens from the papilla were negative for neoplasia and the K-ras analysis harbored the same mutation as previously found in the brush specimen. Conclusion: Based on long-term follow-up, the K-ras mutations in all 8 patients with a clinically benign extrahepatic biliary stenosis must be considered as confirmed false-positives. Nevertheless, a false-positive result is infrequent. Therefore, patients with a positive K-ras mutation in biliary cytologic specimens obtained by brushing still require careful, continuing follow-up. (Gastrointest Endosc 2002;55:883-8.)

Aim--To investigate whether mutations in the STK11/LKB1 gene and genes implicated in the colorectal adenoma-carcinoma sequence are involved in Peutz-Jeghers syndrome (PJS) related tumorigenesis.Methods--Thirty nine polyps and five carcinomas from 17 patients (from 13 families) with PJS were analysed for loss of heterozygosity (LOH) at 19p13.3 (STK11/LKB1 gene locus), 5q21 (APC gene locus), 18q21-22 (Smad4 and Smad2 gene locus), and 17p13 (p53 gene locus), and evaluated for immunohistochemical staining of p53. In addition, mutational analysis of K-ras codon 12, APC, and p53 and immunohistochemistry for Smad4 expression were performed on all carcinomas.Results--LOH at 19p was seen in 15 of the 39 polyps and in all carcinomas (n = 5). Interestingly, six of the seven polyps from patients with cancer had LOH, compared with nine of the 31 polyps from the remaining patients (p = 0.01). In one polyp from a patient without a germline STK11/LKB1 mutation, no LOH at 19p or at three alternative PJS candidate loci (19q, 6p, and 6q) was found. No LOH at 5q was observed. However, mutational analysis revealed an APC mutation in four of the five carcinomas. LOH at 17p was not seen in polyps or carcinomas; immunohistochemistry showed expression of p53 in one carcinoma and focal expression in three polyps. At subsequent sequence analysis, no p53 mutation was found. One carcinoma had an activating K-ras codon 12 mutation and another carcinoma showed 18q LOH; however, no loss of Smad4 expression was seen.Conclusions--These results provide further evidence that STK11/LKB1 acts as a tumour suppressor gene, and may be involved in the early stages of PJS tumorigenesis. Further research is needed to see whether LOH in PJS polyps could be used as a biomarker to predict cancer. Differences in molecular genetic alterations noted between the adenoma-carcinoma sequence and PJS related tumours suggest the presence of a distinct pathway of carcinogenesis.

Background/Aims--Grading of Helicobacter pylori induced atrophic gastritis using the updated Sydney system is severely limited by high interobserver variability. The aim of this study was to set up a quantitative test of gastric corpus mucosal atrophy in tissue sections and test its reproducibility and correlation with the Sydney scores of atrophy. Method--Mucosal atrophy was assessed in 124 haematoxylin and eosin stained corpus biopsy specimens by two experienced gastrointestinal pathologists (EB, JL) according to the updated Sydney system as none (n = 33), mild (n = 33), moderate (n = 33), or pronounced (n = 25). In each specimen, the proportions of glands, stroma, infiltrate, and intestinal metaplasia in the glandular zone were measured as volume percentages using a point counting method. The optimal point sample size, intra-observer and interobserver reproducibility, discriminative power for degrees of atrophy, and correlations with H pylori status were evaluated. Results--Counting 400 points in 200 fields of vision provided the smallest sample size that still had excellent intra-observer and interobserver reproducibility (r ≥ 0.96). Overall, the volume percentage of glands (VPGL), infiltrate (VPI), and stroma (VPS) correlated well with the Sydney scores for atrophy (p ≤ 0.003). However, no differences were found between non-atrophic mucosa and mild atrophy. No correlation was found between age and either the Sydney grade of atrophy or the VPGL or VPS. In non-atrophic mucosa and mild atrophy, H pylori positive cases showed a significantly higher VPI than did H pylori negative cases. A lower VPGL was seen in H pylori positive cases than in H pylori negative cases in the mild atrophy group. VPS did not correlate with H pylori status within each grade of atrophy. Conclusion--Point counting is a powerful and reproducible tool for the quantitative analysis of mucosal corpus atrophy in tissue sections. These data favour the combination of "none" and "mild" atrophy into one category, resulting in a three class grading system for corpus atrophy, when using the updated Sydney system.

Background:Treatment and follow-up policy for Barrett’s oesophagus are dependent on the grade of dysplasia. However, sampling error of random biopsy protocols and subjectivity of pathological grading may hamper endoscopic surveillance. Methods:The Amsterdam Comprehensive Cancer Center Barrett Advisory Committee (BAC) is a regional multidisciplinary consultative working-group, offering revision of pathology, revision of pathology plus additional endoscopic diagnostics, or referral for treatment. Results:Between July 1998 and July 1999 30 patients were referred to the B.A.C for advice; eighteen patients were referred because of suspicion of high grade dysplasia. Reassessment of biopsies, including additional quantitative pathology, with or without additional endoscopic diagnostics, led to adjustment of the grading of dysplasia in 15 patients (50%). A suspicion of low grade dysplasia was rejected in nine out of ten cases. Adjustment of the original diagnosis often influenced further therapy or follow-up. Conclusions:Reassessment of conventional pathology, quantitative pathology, and additional diagnostic procedures might improve the accuracy of diagnosis and staging of malignant degeneration of Barrett’s oesophagus, although experience is still limited. The complexity of the management of these patients demands a specialised multidisciplinary approach. A Barrett Advisory Committee can offer valuable contributions to the treatment of patients with Barrett’s oesophagus.

Histomorphometric, electron microscopic, and cell kinetic studies of gastric mucosa were performed in 12 healthy men treated with 100 μg of 15(R)-15-methyl prostaglandin E2(PGE2) orally q.i.d. for 2 mo followed by 2 mo of placebo. Results were compared with 13 control subjects receiving placebo for 4 mo. After PGE2administration, total antral mucosal thickness and antral and corpus foveolar thicknesses increased 36%, 44%, and 51%, respectively, over baseline values. The total number and height of the foveolar cells also increased. These morphologic changes reversed completely within 2 mo of stopping PGE2therapy. After PGE2administration, no evidence of mucosal inflammation or atypia was observed, nor was there any evidence of ultrastructural changes in the overall appearance of the parietal and gastrin cells. The increased thickness of the gastric mucosa could not be explained by alteration of the proliferative activity, as the labeling index and localization of the proliferative compartment remained unchanged after PGE2 therapy. Presumably PGE2 retards senescence and exfoliation of epithelial cells, which explains the foveolar expansion in the presence of unaltered proliferation.

AimTo evaluate similarities and differences between gastric stump cancer and conventional carcinoma in the non-operated stomach.Methods26 stump carcinomas were compared with 24 conventional stomach cancers. Stage, histological type, and demographics were comparable in the two groups. Expression of p53 and p21-Waf1/Cip1 was evaluated by immunohistochemical staining. Helicobacter pylori infection was evaluated by examining haematoxylin-eosin stained slides and immunohistochemistry. Epstein-Barr virus infection was evaluated by RNA in situ hybridisation.ResultsExpression of p53 and p21-Waf1/Cip1 was similar in both groups and positive in more than half of the patients. H pylori infection was observed in six stump carcinomas and 17 conventional carcinomas in the intact stomach (p < 0.01). RNA in situ hybridisation (EBER1-ISH) for Epstein-Barr virus was positive in nine stump carcinomas and two carcinomas in the non-operated stomach (p < 0.05).ConclusionsThere appear to be aetiological differences between stump carcinoma and cancer in the intact stomach. Further study of these differences may improve our understanding of gastric carcinogenesis in general.

Exposure of the mucosa of the upper aerodigestive tract to carcinogens can induce genetic changes resulting in various independent clones of neoplastic growth, a concept defined as ''field cancerization.'' The risk of developing multiple tumors in this compartment of the body is well established. We studied 6 distinct tumors of the upper aerodigestive tract of a single patient for loss of heterozygosity (LOH), microsatellite instability (MSI), p53 mutations, and K-ras codon 12 point mutations. We detected a unique pattern of LOH and p53 mutations in all 6 tumors. No tumor showed a K-ras mutation or MSI. The results support the mechanism of ''field cancerization'' and illustrate the potential power of molecular techniques to elucidate pathogenesis.

Full clinicopathological details and clinical follow up of a case of malignant transformation within a tailgut cyst are presented. A 43 year old woman presented with signs and symptoms of an imminent threatened abortion. Routine examination identified a coincidental, asymptomatic retrorectal/presacral mass. Following imaging studies, surgical resection was carried out and an adenocarcinoma arising within a pre-existent tailgut cyst was identified by microscopy. Four years later the patient presented with neurological symptoms consistent with local recurrence of the tumour. Surgical biopsies confirmed this diagnosis and she was subsequently started on chemotherapy. She died soon after from a cause unrelated to the disease, after declining further active intervention. Differential diagnosis of such cases includes (cystic) teratoma, epidermal cyst, rectal duplication cyst, anal gland cyst and carcinoma, extension of local carcinoma, and metastatic disease. It is recommended that these lesions be completely excised when detected incidentally.