Prostaglandin Levels in Human Colorectal Mucosa (Effects of Sulindac in Patients with Familial Adenomatous Polyposis)

Recent evidence suggests that nonsteroidalantiinflammatory drugs (NSAIDs) may prevent colorectalcancer. The mechanism of action of NSAIDs inchemoprevention is unknown but may be linked to theireffect on mucosal prostaglandin levels. Levels of fivemajor prostaglandin metabolites were measured by gaschromatography-mass spectrometry in biopsy specimens offlat rectal mucosa from four patients with familial adenomatous polyposis (FAP) before and aftersulindac therapy and from five healthy individuals. Theprostaglandin present at highest concentration in rectalmucosa from FAP and control subjects was prostaglandin E₂. The concentration of thromboxaneB₂ alone was significantly elevated in FAPpatients compared to controls (P = 0.016). In FAPpatients treated with sulindac, all prostaglandinmetabolite levels were significantly reduced compared to pretreatmentlevels (P < 0.05) except prostaglandin D₂(P = 0.07). Prostaglandins D₂, E₂,F₂, and 6-keto-F₁levels also were significantly reduced in FAP patients on sulindac compared to healthy controls (P< 0.05). However, interpatient heterogeneity ofresponse to sulindac was evident with changes rangingfrom +19% to –89%, and the patient with thegreatest reductions after sulindac developed colorectal cancerafter 35 months of therapy. Sulindac treatment, at drugdoses shown to regress colorectal adenomas in FAPpatients, has heterogeneous effects on the level ofmajor prostaglandins in their rectal mucosa and maynot prevent colorectal cancer due to uncoupling ofprostaglandin levels and carcinogenesis.     

Medical Residents' Colorectal Cancer Screening May Be Dependent on Ambulatory Care Education

Colorectal cancer results in significantmorbidity and mortality in the United States. Screeningis a critical component of cancer prevention. However,research has suggested that physicians mayinconsistently adhere to surveillance guidelines. Sinceresidency training can significantly impact upon futurepractice patterns, assessment of postgraduate colorectalcancer education is important. This retrospective chart review of patients 50 years of agecompared screening performed by resident physicians' indifferent internal medicine residency programs at TheGeorge Washington University Medical Center. Resident physicians who received multiple lectures incolorectal cancer surveillance or were required todocument performance of screening on a medical recordpreventive care summary form performed significantly more rectal examinations (P < 0.0004), fecaloccult blood testing (P < 0.00001), and flexiblesigmoidoscopies (P < 0.00001) when compared to otherresident physicians. Postgraduate education shouldemploy multiple education techniques and reinforcementprocedures to increase physician compliance with cancerscreening.     

Perioperative Allogeneic Blood Transfusion and Serum Levels of Immunosuppressive Acidic Protein in Patients Undergoing Resection of Colorectal Carcinoma

Serum levels of immunosuppressive acidic protein(IAP) were determined in 68 patients undergoingresection of colorectal cancer and 21 healthy subjects.Eighteen patients had perioperative transfusion of allogeneic blood (transfused patients) and 50patients had no blood transfusion (nontransfusedpatients). Transfused patients had a higher incidence ofnodal involvement, advanced disease, and noncurative surgery compared to nontransfused patients, butthe difference did not reach a statistical significance.Hemoglobin concentration and serum albumin level werelower in transfused patients, although there was no statistically significant difference.Preoperative serum IAP level was higher in the patientswith nodal involvement and advanced disease and thosewith moderately or poorly differentiated tumor, though this was not statistically significant.The preoperative serum IAP level was higher in patientsthan in controls, but the difference did not reachstatistical significance. Serum IAP level roseimmediately after the operation. In nontransfused patients,the serum IAP level returned to the preoperative valueby three months after the operation. In contrast, theserum IAP level of transfused patients remained significantly higher than the preoperativevalue (P < 0.05) at three months after the operation.These findings indicated that perioperative transfusionof allogeneic blood elevated the serum IAP level for a considerable period after theoperation.     

Detection of Pancreatic Carcinoma (Diagnostic Value of K-ras Mutations in Circulating DNA from Serum)

Somatic activating mutations at codon 12 of theK-ras gene are present in the majority of exocrinepancreatic cancers and occur early in tumorgenesis. Theaim of this study was to test the feasibility of using a mutated K-ras gene from the serum as apotential tumor marker for detection of exocrinepancreatic carcinoma. Codon 12 K-ras mutations wereexamined in DNA extracted from the sera of 20 patients with pancreatic carcinomas, six patients withchronic pancreatitis, and five healthy individuals.K-ras gene mutations at codon 12 were detected in thesera of 14 of 20 patients with pancreatic carcinoma and in none of the six patients with chronicpancreatitis, or in the five healthy controls. Elevationof either CA19-9 or K-ras mutation was detected in 19/20patients. These results suggest that K-ras abnormalities in serum could be used as apotential tumor marker in patients with a pancreaticlesion. The absence of K-ras mutations in serum andpresence of CA19-9 in the normal range make thediagnosis of pancreatic cancer unlikely.     

粪便中p53与APC突变检测在大肠癌诊断中的意义

目的探讨在大肠癌患者粪便中检测p53、APC基因突变的可行性及其应用前景和意义。方法从36例大肠癌患者、10例大肠腺瘤患者以及30例正常对照者的粪便中分别提取DNA,应用PCR-SSCP法检测粪便中p53、APC基因突变情况。结果36例大肠癌患者粪便中p53及/或APC基因突变检出率为77.78%(19/36),二者突变率分别为52.78%(19/36)和36.11%(13/36);10例大肠腺瘤中p53基因突变检出率为0%,APC为20%;30例正常对照粪便中p53、APC基因突变检出率均为0%。p53的突变随大肠癌分化程度的降低而增高(P<0.05);APC基因突变与大肠癌组织学类型无关(P>0.05)。结论联合检测粪便中p53与APC突变在大肠癌诊断和筛查中有潜在的应用价值。     

Novel Expression and Regulation of Gastrin Gene in Human Ovarian Cancer Cell Line, SW626

Gastrin-secreting tumors have been identified inectopic locations including the ovary; the mechanismsregulating gastrin gene expression, its distribution,and signaling pathways in these ectopic tissues are not known. The purpose of our present studywas to determine: (1) whether the gastrin gene andpeptide could be detected in ovarian cancer cell lines,(2) if functional gastrin releasing peptide receptors (GRP-R) are present, and (3) whether gastringene expression is altered by GRP. Five ovarian cancercell lines (SW626, OVCA 420, OVCA 429, OVCA 432, andOVCA 433) were analyzed. We identified gastrin gene and peptide expression in the SW626 cell linebut not in the OVCA lines. SW626 cells express afunctional GRP-R that is correctly coupled to theCa²⁺ signaling pathway. Treatment of SW626cells with bombesin, the amphibian equivalent of GRP, inhibitedexpression of the gastrin gene in a time- anddose-dependent fashion. The SW626 ovarian cancer cellline will provide a useful model to further defineregulation and expression of both the gastrin gene andpeptide in ectopic (nongastrointestinal)tissues.     

Expression of p53 and p21WAF1/CIP1 Proteins in Gastric and Esophageal Cancers (Comparison with Mutations of the p53 Gene)

The p53 gene has been shown to be commonlymutated in various human cancers, and mutant p53 can actas a dominant oncogene. The intact p53 protein is alsoknown to induce the cyclin-dependent kinase inhibitor p21^WAF1/CIP1 and is implicated incell cycle arrest. We investigated p53 gene alterationsin gastric adenocarcinoma and esophageal squamous cellcarcinoma to elucidate the association of the nuclearaccumulation of the p53 protein and/orp21^WAF1/CIP1 protein. Abnormalities of thetumor suppressor gene p53 protein and the expression ofp21^WAF1/CIP1 protein were analyzed byimmunohistochemical techniques in 32 cases of gastric adenocarcinoma and 15 cases ofesophageal squamous cell carcinoma. Twenty cases ofgastric cancer and five cases of esophageal cancer werealso analyzed for p53 gene mutation by polymerase chain reaction and direct nucleotide sequencing.Overexpression of p53 protein was found in 13/32 (41%)of gastric cancers and 5/15 (33%) of esophageal cancers.We found immunodetectable p53 in 10/14 cases with mutations and in none of 11 cases withoutmutations in gastric and esophageal cancers. Hence,immunohistochemical and genetic analyses gave concordantresults in 84% of 25 cases, revealing a good correlation between immunostaining of p53 and missensemutation of the p53 gene. p53 immunostaining was notobserved in cases with frameshift or splicing mutation.The expression of p21^WAF1/CIP1 protein wasfound in 9/32 (29%) of gastric cancers and 4/15 (27%) ofesophageal cancers and in 2/14 (14%) cases withalteration of the p53 gene and in 5/11 (45%) without.These results suggest that abnormalities of p53 may be closely associated with the pathogenesisof gastric adenocarcinoma and esophageal squamous cellcarcinoma and that the immunoreactivity of p53 proteinis a general indicator of the tumors with altered p53 function. The expression ofp21^WAF1/CIP1 protein was suppressed in theneoplastic tissues with and without p53 genealteration.     

Mutations of the APC Gene in Human Sporadic Colorectal Cancers

Background: Mutations of the APC gene are reported to occur frequently in sporadic colorectal adenomas and adenocarcinomas. We studied APC gene mutations in cases of human sporadic colorectal cancer in order to evaluate their correlation with pathologic characteristics and clinical prognosis. Methods: Most of the mutations of the APC gene (95%) are nonsense or frame shift mutations, encoding for truncated APC proteins. For this reason, mutation detection of the APC gene was performed using the in vitro synthesized protein (IVSP) assay, analysing the region between nucleotide 2058 and nucleotide 5079 of the gene, containing the mutation cluster region. Results: Out of 58 cases of colorectal cancer, 29 presented a mutated form of APC (mutation frequency 50%). We did not find a statistically significant correlation between APC gene mutation and age, sex, localization of the primary tumour, grading, Crohn-like lymphoid reaction or presence of residual adenoma. Tumours with low invasivity (Dukes' stages A and B) were less frequently mutated (12/27, 44.5%) than tumours of Dukes' stage C (15 out of 21, 71.4%), which developed macroscopically secondary metastasis with variable latency after surgery. Highly invasive tumours with synchronous metastases (Dukes' stage D) had, instead, a low frequency of APC mutations (20%, 2/10) ( P = 0.02, compared with Dukes' stages A, B and C). Conclusions: These data suggest that more aggressive Dukes' stage D tumours develop metastasis by means of an unknown mechanism, independent of APC mutation.     

Performance Characteristics and Comparison of Two Immunochemical and Two Guaiac Fecal Occult Blood Screening Tests for Colorectal Neoplasia

A new immunochemical test for stool Hb, FlexSureOBT, was compared with the immunochemical HemeSelect andguaiac Hemoccult II and Hemoccult SENSA tests. Blindeddevelopment of test cards smeared with stools having added human blood showed betteranalytical sensitivity of FlexSure OBT (0.2 ml blood/100g feces), than Hemoccult SENSA (0.5 ml) or HemoccultII (1.0 ml). All four stool tests were prepared by 403 subjects having endoscopic examinations.The guaiac tests and FlexSure OBT were easy to prepareand develop. The positivity rate of Hemoccult SENSA was8.7%, Hemoccult II 6%, FlexSure OBT 4.2%, and HemeSelect 3.4%. In this mainly asymptomatic(97%) population, 98% were free of clinicallysignificant neoplasia (five had cancers, three hadadenomas 1.0 cm). Sensitivity for cancers oradenomas 1.0 cm was similar for all tests (62.5-86%, NS) andHemoccult SENSA had the lowest specificity (92% vs95-98%, P < 0.05); but both Hemoccult II andHemoccult SENSA had significantly lower predictivepositive values (21% and 14%) than either FlexSure OBT(29%) or HemeSelect (50%) (P < 0.05). If bothHemoccult SENSA and FlexSURE OBT were positive in thesame subjects (1.7%), sensitivity for cancer or adenomas 1.0 cm (50%) was not significantly betterthan guaiac tests, but specificity (99.2%) andpredictive positive (57%) values were improved (P <0.05). In this population, guaiac tests were assensitive as immunochemical tests for clinically significantcolorectal neoplasia, but with significantly lowerpredictive positive values. A combination of a sensitiveguaiac test (Hemoccult SENSA) and a specificconfirmatory test for human Hb (FlexSure OBT) provided highspecificity, comparable to HemeSelect.     

国人脂蛋白脂肪酶基因突变的筛查

目的筛查天津地区脂蛋白脂肪酶基因突变情况,并探讨其对血脂水平的影响。方法利用聚合酶链反应—单链构象多态性分析技术对386例样本(血脂正常组278例,血脂异常组108例)的脂蛋白脂肪酶基因进行突变筛查,对可疑突变的扩增样品进行DNA序列测定。对于频率较高的多态性位点,引入限制性核酸内切酶位点利用聚合酶链反应限制片长多态性进行鉴定。结果在386例样本中,共检出4种突变,检出率为14.5%,其中1例为目前国内外未见报道的外显子3 Leu103→Leu同义突变杂合子,1例为目前亚洲首报的外显子5 Pro207→Leu突变杂合子,3例内含子3受位剪接点上游6 bp的C→T转换的突变杂合子,1例Ser447→stop突变纯合子,50例Ser447→stop突变杂合子。结论我国天津地区人群存在着广泛的脂蛋白脂肪酶基因变异,既具有与大多数国家相同的Ser447→stop多态性位点,也具有自身的特点。     

Mutation Spectrum of Familial Adenomatous Polyposis Patients in Turkish Population: Identification of 3 Novel APC Mutations

BackgroundFamilial adenomatous polyposis (OMIM #175100) and MUTYH-associated polyposis (OMIM #608456) are rare cancer-prone disorders characterized by hundreds of adenomatous polyps in the colon and rectum, which have a high probability of malignant transformation. Attenuated familial adenomatous polyposis is a variant of familial adenomatous polyposis, which is a term used for the condition in which patients have less than 100 colorectal polyps. Germline heterozygous Adenomatous polyposis coli (APC) and biallelic MUTYH (mutY DNA glycosylase) pathogenic variations are responsible for familial adenomatous polyposis and MUTYH-associated polyposis respectively. The aim of this study is to discuss the clinical manifestations of patients having pathogenic APC and MUTYH variations.MethodsWe included 27 probands who have more than 10 colonic polyps in this study. After evaluation of their clinical and family histories, the probands were screened for APC and MUTYH variations via next generation sequencing. The family members of the probands carrying pathogenic variations were screened via Sanger sequencing. ResultsAmong 27 probands, pathogenic APC and MUTYH variations were detected in 3 and 6 probands respectively. In the APC gene, 3 novel truncating variations (p.Leu360*, p.Leu1489Phefs*23, and p.Leu912*) were detected in 3 unrelated probands. In the MUTYH gene, only 2 distinct pathogenic variations were detected (p.Pro295Leu and p.Glu480del) in the homozygous or compound heterozygous state.ConclusionIn this study, molecular etiology was clarified in 9 familial polyposis patients. The p.Pro295Leu and p.Glu480del variations seem to be common in the Turkish population and may be considered as a first-step genetic test in Turkish familial polyposis patients showing autosomal recessive inheritance. However more studies are needed to reveal the exact frequency of these variations.     

高内涵技术检测H_2O_2诱导心肌细胞凋亡实验方法的探讨

目的探讨高内涵分析方法检测心肌细胞凋亡的优缺点,为细胞凋亡检测实验方法提供参考。方法用不同浓度过氧化氢(H_2O_2)诱导乳鼠心肌细胞凋亡模型,FITC Annexin V Apoptosis Detection试剂盒及Hoechst探针进行染色后,用高内涵仪器Opretta system进行检测和分析心肌细胞凋亡相关指标,对比细胞计数试剂盒-8(CCK-8)法检测细胞活性数据,判断心肌细胞凋亡程度。结果 300μmol/L浓度的H_2O_2诱导细胞凋亡模型最为理想,高内涵筛选计算早期凋亡细胞占61.4%,晚期凋亡细胞占38.2%,显微成像图片显示细胞凋亡明显。结论 H_2O_2诱导心肌细胞凋亡造模方法普遍实用,高内涵分析方法直观、简便、有效,单次检测取得的数据丰富,可进行高通量筛选,可以用于大量细胞样品的细胞凋亡检测。     

Comparison of Quality Measures for Detection of Neoplasia at Screening Colonoscopy

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粪便转铁蛋白检测对上消化道肿瘤的筛检作用

目的 评价粪便转铁蛋白检测对上消化道肿瘤的筛检作用.方法 采用单克隆血红蛋白检测法和粪便转铁蛋白检测法对40例经胃镜确诊的上消化道肿瘤患者进行粪便潜血检测,比较两者阳性率差异及其与胃镜结果的符合率.结果 所检40例标本中,单克隆血红蛋白法阳性率20%,粪便转铁蛋白法阳性率82.5%,差异有显著意义(P＜0.01).结论 粪便转铁蛋白检测对上消化道肿瘤性出血敏感性高于单克隆血红蛋白法,适用于上消化道肿瘤的过筛检验.