胃癌组织中抑癌基因APC／MCC杂合性缺失的研究

应用多聚酶链反应（ＰＣＲ）与限制性片段长度多态性分析法（ＲＦＬＰ），对４５例手术切除胃癌组织腺癌性息肉基因（ＡＰＣ）／结直肠癌突变基因（ＭＣＣ）杂合性缺失（ＬＯＨ）进行分析。结果表明ＡＰＣ、ＭＣＣ基因ＬＯＨ串分别为２１．７％（５／２３）和３１．３％（５／１６）．ＡＰＣ／ＭＣＣ缺失率为３０．０％（９／３０）。ＬＯＨ率在肠型及胃型胃癌中无明显差异，与肿瘤大小、组织学分类、浸润深度、淋巴转移及临床分期无关。一例早期胃癌出现ＭＣＣ基因缺失。结果提示ＡＰＣ／ＭＣＣ基因ＬＯＨ与两型胃癌的早期发生及发展有关。

Two cases of adenocarcinoma occurring in sporadic fundic gland polyps observed by magnifying endoscopy with narrow band imaging

Gastric fundic gland polyps(FGPs) are common nonadenomatous gastric polyps arising from normal fundic mucosa without Helicobacter pylori(H. pylori) infection. Although systemic FGPs associated with familial adenomatous polyposis(FAP) often have dysplasia, there are few reports of dysplasia occurring in sporadic F G P s, e s p e c i a l l y w h e n d e t e c t e d b y m a g n i f y i n g endoscopy with narrow band imaging(ME-NBI). We experienced two cases of adenocarcinoma occurring in sporadic FGPs, and their ME-NBI findings were very useful for differentiating FGP with cancer from nondysplastic FGP. A 68-year-old man and a 63-year-old woman were referred to our institution for medical checkup. H. pylori was negative in both patients. Endoscopic examination revealed a small reddishpolypoid lesion on the anterior wall of the upper gastric body and several FGPs. ME-NBI showed an irregular microvascular architecture composed of closed loop- or open loop-type vascular components, plus an irregular microsurface structure composed of oval-type surface components which was different from that of FGPs. FAP was denied because of the absence of colon polyps and no familial history of FAP. Pathological diagnosis was adenocarcinoma occurring in sporadic FGP.

Proton pump inhibitors and an emerging epidemic of gastric fundic gland polyposis

Fundic gland polyps are now commonly recognized during endoscopy. These polyps are benign, often multiple and usually detected in the gastric body and fundus. In the past, these polyps were sometimes associated with familial adenomatous polyposis. In recent years, it has become evident that increasing numbers of these polyps are being detected during endoscopic studies, particularly in patients treated with proton pump inhibitors for prolonged periods. In some, dysplastic changes in these polyps have also been reported. Recent studies have suggested that there may be no increase in risk of colon cancer with long-term proton pump inhibitor therapy. While temporarily reassuring, ongoing vigilance, particularly in those genetically predisposed to colon cancer, is still warranted.

Clinical predictors of colorectal polyps and carcinoma in a low prevalence region: Results of a colonoscopy based study

AIM: To estimate the prevalence of colorectal cancer (CRC) in patients with long lasting colonic symptoms undergoing total colonoscopy; and to establish clinical features predicting its occurrence. METHODS: This prospective study was carried out in Imam Hospital, Tabriz University of medical sciences, Iran. Continuous patients with long lasting lower gastrointestinal tract symptoms who had the criteria of a colonoscopy were included. The endoscopist visualized the caecum documented by a photo and/or a specimen from terminal ileum. RESULTS: Four hundred and eighty consecutive symptomatic patients [mean age (SD): 42.73 (16.21)] were included. The prevalence of colorectal neoplasia was 15.3% (34 subjects) and 37.7% (181 subjects) had a completely normal colon. Adenomatous polyps were detected in 56 (11.7%) patients, in 12.3% of men and 10.9% of women. The mean age of the patients with a polyp was significantly higher than the others (49.53 ± 14.16 vs 41.85 ± 16.26, P = 0.001). Most of the adenomatous polyps were left sided and tubular; only 22.5% of polyps were more than 10 mm. Cancer was detected in 16 (3.6%) of our study population, which was mostly right sided (57.2%). The mean age of patients with cancer was significantly higher than the others (60.25 ± 8.26 vs 42.13 ± 16.08, P < 0.005) and higher than patients with polyps [60.25 (8.26) vs 49.53 (1.91) (P < 0.0005)]. None of the symptoms (diarrhea, abdominal pain, rectal bleeding, constipation, altering diarrhea and constipation, history of cancer, known irritable bowel disease, history of polyp and fissure or family history of cancer) were predictors for cancer or polyps, but the age of the patient and unexplainedanemia independently predicted cancer. CONCLUSION: Less advanced patterns and smaller sizes of adenomas in Iran is compatible with other data from Asia and the Middle East, but in contrast to western countries. Prevalence of colonic neoplasia in our community seems to be lower than that in western population. Colonic symptoms are not predictors for polyps or cancer but unexplained anemia and elder age can predict CRC.

Deficiency of Adenomatous Polyposis Coli protein in sporadic colorectal adenomas and its associations with clinical phenotype and histology

AIM： To evaluate the frequency of the loss of the Adenomatous Polyposis Coil （APC） protein and to compare the APC status with the characteristics of colorectal adenomas. METHODS： Immunohistochemical analysis of the APC protein was performed on 118 adenomas and the results were compared with parameters of malignant potential, location of adenomas, macroscopic appearance and age of the patients. RESULTS： A complete loss of the APC protein was found in 28 （24%） adenomas, while 90 （76%） were APC positive. The mean size of adenomas was 13.5± 14.2 mm （95% CI 10.5-16.5） in APC-positive, and 13.8 ±15.5 mm （95% CI 7.8-19.8） in APC-negative adenomas （P = 0.364）. Statistical analysis revealed no difference between APC-positive and negative adenomas as to the histological type （P = 0.327） and grade of dysplasia （P =0.494）. We found that even advanced adenomas did not differ in their APC status from the non-advanced tumors （P = 0.414）. Finally, no difference was found when the location （P = 0.157）, macroscopic appearance （P = 0.571） and age of patients （P = 0.438） were analysed and compared between both APC positive and negative adenomas. CONCLUSION： Most adenomas expressed full-length APC protein, suggesting that protein expression is not a reliable marker for assessment of APC gene mutation. Complete loss of APC protein did not influence morphology, location, or appearance of adenomas, nor was it affected by the patient＇s age.

Hyperplastic polyposis associated with two asynchronous colon cancers

We report a patient with hyperplastic polyposis who had two asynchronous colon cancers, a combined adenoma-hyperplastic polyp, a serrated adenoma, and tubular adenomas. Hyperplastic polyposis is thought to be a precancerous lesion; and adenocarcinoma arises from hyperplastic polyposis through the hyperplastic polyp-adenoma-carcinoma sequence. Most polyps in patients with hyperplastic polyposis present as bland- looking hyperplastic polyps, which are regarded as non- neoplastic lesions; however, the risk of malignancy should not be underestimated. In patients with multiple hyperplastic polyps, hyperplastic polyposis should be identified and followed up carefully in order to detect malignant transformation in the early stage.