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Recent guidelines for colorectal cancer screening have reached different conclusions on whether computed tomographic colonography (CTC) is an acceptable screening option, and the Centers for Medicare & Medicaid Services recently decided not to cover CTC screening. The rationale against recommending or covering CTC screening includes concerns about radiation exposure, false-negative rates for small polyps, the discovery of extracolonic findings, variability in performance, a lack of targeted studies, a higher adenoma rate in the Medicare-eligible age group, and an absence of evidence that covering CTC would increase overall screening rates. Similar concerns can be raised for other recommended and covered colon cancer screening tests, but it seems that CTC is being held to a new and higher standard.

The Aspirin/Folate Polyp Prevention Trial found that aspirin, but not folic acid, reduced recurrence of colorectal adenomas. This study examined whether treatment effects on inflammation markers explained the trial results. The trial had a factorial design with three aspirin (placebo, 81, and 325 mg/d) and two folic acid (placebo and 1 mg/d) groups. There were 884 subjects who had colonoscopic evaluation for adenomas at year 3 and plasma levels of C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor [alpha] (TNF-[alpha]), soluble TNF receptor type II (sTNF-R2), and IL-1 receptor antagonist (IL-1Ra) measured at baseline and year 3. Among individuals not receiving folic acid, there was a 4% decrease (mean ratio of year 3 to baseline levels = 0.96, 95% confidence interval [CI] = 0.82 to 1.14) in CRP for a period of 3 years in the 325 mg of aspirin group vs a 20% increase (mean ratio = 1.20, 95% CI = 1.03 to 1.41) in the placebo group (P = .027). By contrast, the reverse was observed among individuals who also received folic acid ([P.sub.interaction] = .013). Changes in inflammation markers were not associated with adenoma recurrence. Low-dose aspirin (325 mg/d) is beneficial in stabilizing CRP levels, which may be abrogated by folate. Nevertheless, inflammation markers do not mediate the chemopreventive effect of aspirin on colorectal adenomas. J Natl Cancer Inst 2009;101:1650-1654 DOI: 10.1093/jnci/djp346

Background: Suggested intervals for postpolypectomy surveillance colonoscopy are currently based on the adenoma findings from the most recent examination. Objective: To determine the risk for clinically significant adenoma recurrence on the basis of the results of 2 previous colonoscopies. Design: Prospective cohort study. Setting: Academic and private centers in North America. Patients: Participants in an adenoma chemoprevention trial in which all participants had 1 or more adenoma found on complete colonoscopy at entry. For this analysis, only participants whose qualifying adenoma was their first were included. All participants then underwent second and third study colonoscopies at roughly 3-year intervals. Measurements: Proportion of patients with high-risk findings at the third study colonoscopy--either at least 1 advanced ([greater than or equal to]1 cm or advanced histology) adenoma or multiple ([greater than or equal to]3) adenomas. Results: Fifty-eight of 564 participants (10.3%) had high-risk findings at the third study examination. If the second examination showed high-risk findings, then results from the first examination added no significant information about the probability of high-risk findings on the third examination (18.2% for high-risk findings on the first examination vs. 20.0% for low-risk findings on the first examination; P = 0.78). If the second examination showed no adenomas, then the results from the first examination added significant information about the probability of high-risk findings on the third examination (12.3% if the first examination had high-risk findings vs. 4.9% if the first examination had low-risk findings; P = 0.015). Limitation: This observational study cannot specifically examine adenoma recurrence risk at intervals suggested for patients with low-risk adenomas (for example, 5 years vs. 10 years). Conclusion: Information from 2 previous examinations may help identify low-risk populations that benefit little from intense surveillance. Surveillance guidelines might be tailored in selected patients to use information from 2 previous examinations, not just the most recent one. Primary Funding Source: National Institutes of Health.

Background Frequent use of nonsteroidal anti-inflammatory drugs (NSAIDs) has been shown to reduce the risk of colorectal adenomas in randomized trials. We examined the persistence of the protective effect after the cessation of randomized aspirin treatment and whether it is affected by the duration and frequency of subsequent NSAID use. Methods We used data from the Aspirin/Folate Polyp Prevention Study (AFPPS), in which 1121 subjects were randomly assigned to receive placebo or aspirin (81 or 325 mg/d) for 3 years. After the end of treatment and a follow-up colonoscopy, AFPPS participants were invited to remain under follow-up until their next surveillance colonoscopies, scheduled 3-5 years later. Information regarding use of NSAIDs during posttreatment follow-up was gathered periodically via questionnaires. Average weekly NSAID use was classified as sporadic ( Results A total of 850 subjects underwent a posttreatment colonoscopy, on average 4 years after the end of study treatment. The protective effect of 81 mg of aspirin for colorectal adenomas persisted with continued posttreatment NSAID use. The risk of any adenoma among frequent NSAID users was 26.8% vs 39.9% among placebo subjects who later used NSAIDs sporadically (adjusted relative risk = 0.62, 95% confidence interval [Cl] = 0.39 to 0.98; [P.sub.trend] with NSAID use frequency = .03). The unadjusted absolute risk reduction was 13.1 percentage points (95% Cl = -0.3 to 26.5 percentage points) (P = .07). Results for 325 mg of aspirin were similar, although not statistically significant. For advanced lesions, small numbers of endpoints limited the analysis, but findings among subjects randomly assigned to 81 mg of aspirin suggested a protective association regardless of posttreatment NSAID use. Conclusion Long-term and frequent use of NSAIDs may enhance the chemopreventive effect of aspirin against colorectal neoplasia.

Background: Stool DNA testing is a new approach to colorectal cancer detection. Few data are available from the screening setting. Objective: To compare stool DNA and fecal blood testing for detection of screen-relevant neoplasia (curable-stage cancer, high-grade dysplasia, or adenomas >1 cm). Design: Blinded, multicenter, cross-sectional study. Setting: Communities surrounding 22 participating academic and regional health care systems in the United States. Participants: 4482 average-risk adults. Measurements: Fecal blood and DNA markers. Participants collected 3 stools, smeared fecal blood test cards and used same-day shipment to a central facility. Fecal blood cards (Hemoccult and HemoccultSensa, Beckman Coulter, Fullerton, California) were tested on 3 stools and DNA assays on 1 stool per patient. Stool DNA test 1 (SDT-1) was a precommercial 23-marker assay, and a novel test (SDT-2) targeted 3 broadly informative markers. The criterion standard was colonoscopy. Results: Sensitivity for screen-relevant neoplasms was 20% by SDT-I, 11% by Hemoccult (P = 0.020), 21% by HemoccultSensa (P = 0.80); sensitivity for cancer plus high-grade dysplasia did not differ among tests. Specificity was 96% by SDT-1, compared with 98% by Hemoccult (P < 0.001) and 97% by HemoccultSensa (P = 0.20). Stool DNA test 2 detected 46% of screen-relevant neoplasms, compared with 16% by Hemoccult (P < 0.001) and 24% by HemoccultSensa (P < 0.001). Stool DNA test 2 detected 46% of adenomas 1 cm or larger, compared with 10% by Hemoccult (P < 0.001) and 17% by HemoccultSensa (P < 0.001). Among colonoscopically normal patients, the positivity rate was 16% with SDT-2, compared with 4% with Hemoccult (P = 0.010) and 5% with HemoccultSensa (P = 0.030). Limitations: Stool DNA test 2 was not performed on all subsets of patients without screen-relevant neoplasms. Stools were collected without preservative, which reduced detection of some DNA markers. Conclusion: Stool DNA test 1 provides no improvement over HemoccultSensa for detection of screen-relevant neoplasms. Stool DNA test 2 detects significantly more neoplasms than does Hemoccult or HemoccultSensa, but with more positive results in colonoscopically normal patients. Higher sensitivity of SDT-2 was particularly apparent for adenomas.

Background: Even when primary care physicians have face-to-face discussions with patients before referring them for screening colonoscopy, patient nonadherence can be substantial. Often, primary care physicians lack sufficient time to educate patients and address their potential misconceptions and fears about this procedure. Objective: To test whether an informational brochure sent to patients' home addresses after referral for screening colonoscopy would increase patient completion of the procedure. Design: Randomized, controlled trial. Setting: 2 general internal medicine practices affiliated with the University of Colorado Health Sciences Center. Patients: 781 consecutive patients 50 years of age or older referred by their primary care physicians for screening colonoscopy. Intervention: Patients were randomly assigned to receive usual care (control group) versus usual care plus an informational brochure (intervention group). The brochure was mailed within 10 days of referral for screening colonoscopy; it mentioned the name of the patient's primary care physician and encouraged patients to schedule a procedure. It also described colorectal cancer and polyps and the similar lifetime risks for colorectal cancer for men and women, colonoscopy and risk for perforation, the nature of bowel preparation for the procedure, and alternative screening tests. Measurements: Rates of adherence to screening colonoscopy in the 2 study groups. Results: The overall adherence rate was 11.7 percentage points (95% Cl, 5.1 to 18.4 percentage points) greater in the intervention group than in the control group (70.7% vs. 59.0%). Older patients were more adherent than younger patients. Patients with low-income insurance plans, such as Medicaid, were less adherent despite being sent a brochure. Limitations: The small number of clinical practices and minority patients may limit generalizability. In addition, it was not possible to determine the degree to which adherence was influenced by a reminder to schedule a procedure versus detailed information about colonoscopy. Conclusions: An inexpensive mailed brochure is an effective way to increase patient adherence to primary care physician referral for screening colonoscopy.

Background: Previous research suggests that the G315A single-nucleotide polymorphism in the ornithine decarboxylase (ODC) gene may be a genetic marker for risk of colorectal neoplasia and may also modify the association of aspirin use with risk. Methods: We tested these hypotheses among participants in the Aspirin/Folate Polyp Prevention Study who were randomly assigned to placebo or to aspirin treatment (81 or 325 mg daily) and followed for 3 years for the occurrence of new adenomas. Genomic DNA from 973 subjects was analyzed for ODC genotype. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated to test the association between ODC genotype and adenoma occurrence and interactions with aspirin treatment. All statistical tests were two-sided. Results: Of the 973 subjects, 54% were homozygous wild-type (GG), 7% were homozygous variant (AA), and 39% were heterozygous individuals; the allele frequencies varied statistically significantly by race and ethnicity. Among these subjects, the absolute risk of any adenoma was 45% and the risk of an advanced lesion was 10%. Overall, no association was found between ODC genotype and the occurrence of new adenomas, but genotype did modify the effect of aspirin on adenoma risk. Although aspirin treatment had no protective effect among subjects with a GG genotype, among subjects with at least one A allele, it was associated with statistically significant reduced risks of any adenoma (RR = 0.77, 95% CI = 0.63 to 0.95; P = .2, [P.sub.interaction] = .04) and of advanced lesions (RR = 0.51, 95% CI = 0.29 to 0.90; P = .02, [P.sub.interaction] = .02). Among subjects with at least one A allele, 40.8% who took aspirin versus 52.9% who took placbo developed adenomas; 7.1% versus 14.0% developed advanced lesions. Conclusion: ODC genotype may modify the response to aspirin treatment for colorectal adenoma prevention.

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The most commonly recognized high-risk group for colorectal cancer (CRC) is individuals with a positive family history. It is generally recognized that those with a first-degree relative (FDR) with CRC are at a 2-fold or higher risk of CRC or advanced neoplasia. FDRs of patients with advanced adenomas have a similarly increased risk. Accordingly, all major US guidelines recommend starting CRC screening by age 40 in these groups. Barriers to screening this group include patient lack of knowledge on family and polyp history, provider limitations in collecting family history, and insufficient application of guidelines.

What is it like to try to capture the flavor and meaning of a revolution while you are in the middle of it? That is what Neil W. Toribara, MD, [...]

ObjectiveSerrated lesions such as sessile serrated adenomas or polyps (SSA/Ps) are important colorectal cancer precursors, but aetiological factors for these lesions are largely unknown. We aimed to determine the effects of calcium and vitamin D supplementation on the incidence of serrated polyps (SPs) in general and hyperplastic polyps and SSA/Ps specifically.DesignParticipants with one or more adenoma at baseline were randomised to receive 1200 mg/day of elemental calcium, 1000 IU/day of vitamin D3, both or neither agent. Treatment continued for 3 or 5 years, when risk of polyps was determined from surveillance colonoscopy (treatment phase). Outcomes after treatment ceased were also assessed (observational phase). Adjusted risk ratios (aRRs) of SPs were determined via multivariable generalised linear models.ResultsSPs were diagnosed in 565 of 2058 (27.5%) participants during the treatment phase and 329/1108 (29.7%) during the observational phase. In total, 211 SSA/Ps were identified during follow-up. In the treatment phase, there was no effect of either calcium or vitamin D on incidence of SSA/Ps. However, during the later observational phase, we observed elevated risks of SSA/Ps associated with calcium alone and calcium+vitamin D treatment (aRR (95% CI): 2.65 (1.43 to 4.91) and 3.81 (1.25 to 11.64), respectively).ConclusionIn a large multicentre chemoprevention study, we found evidence that calcium and vitamin D supplementation increased the risk of SSA/Ps. This appeared to be a late effect: 6–10 years after supplementation began. These possible risks must be weighed against the benefits of calcium and vitamin D supplementation.Trial registrationnumberNCT00153816; Results.

Rationale:Colorectal cancer (CRC) is preventable through screening, with colonoscopy and fecal occult blood testing comprising the two most commonly used screening tests. Given the differences in complexity, risk, and cost, it is important to understand these tests’ comparative effectiveness.Study design:The CONFIRM Study is a large, pragmatic, multicenter, randomized, parallel group trial to compare screening with colonoscopy vs. the annual fecal immunochemical test (FIT) in 50,000 average risk individuals. CONFIRM examines whether screening colonoscopy will be superior to a FIT-based screening program in the prevention of CRC mortality measured over 10 years. Eligible individuals 50–75 years of age and due for CRC screening are recruited from 46 Veterans Affairs (VA) medical centers. Participants are randomized to either colonoscopy or annual FIT. Results of colonoscopy are managed as per usual care and study participants are assessed for complications. Participants testing FIT positive are referred for colonoscopy. Participants are surveyed annually to determine if they have undergone colonoscopy or been diagnosed with CRC. The primary endpoint is CRC mortality. The secondary endpoints are (1) CRC incidence (2) complications of screening colonoscopy, and (3) the association between colonoscopists’ characteristics and neoplasia detection, complications and post-colonoscopy CRC. CONFIRM leverages several key characteristics of the VA’s integrated healthcare system, including a shared medical record with national databases, electronic CRC screening reminders, and a robust national research infrastructure with experience in conducting large-scale clinical trials. When completed, CONFIRM will be the largest intervention trial conducted within the VA (ClinicalTrials.gov identifier: NCT01239082).

Cancer is fundamentally a genetic disease caused by mutational or epigenetic alterations in DNA. There has been a remarkable expansion of the molecular understanding of colonic carcinogenesis in the last 30 years and that understanding is changing many aspects of colorectal cancer care. It is becoming increasingly clear that there are genetic subsets of colorectal cancer that have different risk factors, prognosis, and response to treatment. This article provides a general update on colorectal cancer and highlights the ways that genetics is changing clinical care.

Colorectal cancer (CRC) is potentially preventable. Chemoprevention, a focus of research for the past three decades, aims to prevent or delay the onset of cancer through the regression or prevention of colonic adenomas. Ideal pharmacological agents for chemoprevention should be cheap and nontoxic. Although data indicate that aspirin can reduce the risk of CRC in the general population, the highest return from chemopreventive strategies would be expected in patients with the highest risk of developing the disease, particularly those with a defined hereditary predisposition. Despite compelling data showing that a large number of chemopreventive agents show promise in preclinical CRC models, clinical studies have yielded conflicting results. This Review provides a historical and methodological perspective of chemoprevention in familial adenomatous polyposis and Lynch syndrome, and summarizes the current status of CRC chemoprevention in humans. Our goal is to critically focus on important issues of trial design, with particular attention on the choice of appropriate trial end points, how such end points should be measured, and which patients are the ideal candidates to be included in a chemopreventive trial.

OBJECTIVES:Individuals whose families meet the Amsterdam II clinical criteria for hereditary non-polyposis colorectal cancer are recommended to be referred for genetic counseling and to have colonoscopic screening every 1–2 years. To assess the uptake and knowledge of guideline-based genetic counseling and colonoscopic screening in unaffected members of families who meet Amsterdam II criteria and their treating endoscopists.METHODS:Participants in the Family Health Promotion Project who met the Amsterdam II criteria were surveyed regarding their knowledge of risk-appropriate guidelines for genetic counseling and colonoscopy screening. Endoscopy/pathology reports were obtained from patients screened during the study to determine the follow-up recommendations made by their endoscopists. Survey responses were compared using Fisher’s Exact and the χ2test. Concordance in participant/provider-reported surveillance interval was assessed using the kappa statistic.RESULTS:Of the 165 participants, the majority (98%) agreed that genetics and family history are important predictors of CRC, and 63% had heard of genetic testing for CRC, although only 31% reported being advised to undergo genetic counseling by their doctor, and only 7% had undergone genetic testing. Only 26% of participants reported that they thought they should have colonoscopy every 1–2 years and 30% of endoscopists for these participants recommended 1–2-year follow-up colonoscopy. There was a 65% concordance (weighted kappa 0.42, 95% CI 0.24–0.61) between endoscopist recommendations and participant reports regarding screening intervals.CONCLUSIONS:A minority of individuals meeting Amsterdam II criteria in this series have had genetic testing and reported accurate knowledge of risk-appropriate screening, and only a small percentage of their endoscopists provided them with the appropriate screening recommendations. There was moderate concordance between endoscopist recommendations and participant knowledge suggesting that future educational interventions need to target both health-care providers and their patients.

In the United States, colorectal cancer (CRC) is the third most common and second most lethal cancer. More than one-tenth of CRC cases (11% of colon cancers and 18% of rectal cancers) have a young onset (ie, occurring in individuals younger than 50 years). The CRC incidence and mortality rates are decreasing among all age groups older than 50 years, yet increasing in younger individuals for whom screening use is limited and key symptoms may go unrecognized. Familial syndromes account for approximately 20% of young-onset CRCs, and the remainder are typically microsatellite stable cancers, which are more commonly diploid than similar tumors in older individuals. Young-onset CRCs are more likely to occur in the distal colon or rectum, be poorly differentiated, have mucinous and signet ring features, and present at advanced stages. Yet, stage-specific survival in patients with young-onset CRC is comparable to that of patients with later-onset cancer. Primary care physicians have an important opportunity to identify high-risk young individuals for screening and to promptly evaluate CRC symptoms. Risk modification, targeted screening, and prophylactic surgery may benefit individuals with a predisposing hereditary syndrome or condition (eg, inflammatory bowel disease) or a family history of CRC or advanced adenomatous polyps. When apparently average-risk young adults present with CRC-like symptoms (eg, unexplained persistent rectal bleeding, anemia, and abdominal pain), endoscopic work-ups can expedite diagnosis. Early screening in high-risk individuals and thorough diagnostic work-ups in symptomatic young adults may improve young-onset CRC trends.

Changes in the methylation levels of DNA from white blood cells (WBCs) are putatively associated with an elevated risk for several cancers. The aim of this study was to investigate the association between colorectal cancer (CRC) and the methylation status of three DNA repetitive elements in DNA from peripheral blood. WBC DNA from 539 CRC cases diagnosed before 60 years of age and 242 sex and age frequency-matched healthy controls from the Australasian Colorectal Cancer Family Registry were assessed for methylation across DNA repetitive elements Alu, LINE-1 and Sat2 using MethyLight. The percentage of methylated reference (PMR) of cases and controls was calculated for each marker. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression adjusted for potential confounders. CRC cases demonstrated a significantly higher median PMR for LINE-1 (p < 0.001), Sat2 (p < 0.001) and Alu repeats (p = 0.02) when compared with controls. For each of the DNA repetitive elements, individuals with PMR values in the highest quartile were significantly more likely to have CRC compared with those in the lowest quartile (LINE-1 OR = 2.34, 95%CI = 1.48–3.70; p < 0.001, Alu OR = 1.83, 95%CI = 1.17–2.86; p = 0.01, Sat2 OR = 1.72, 95%CI = 1.10–2.71; p = 0.02). When comparing the OR for the PMR of each marker across subgroups of CRC, only the Alu marker showed a significant difference in the 5-fluoruracil treated and nodal involvement subgroups (both p = 0.002). This association between increasing methylation levels of three DNA repetitive elements in WBC DNA and early-onset CRC is novel and may represent a potential epigenetic biomarker for early CRC detection.

Debate continues as to the usefulness of assessing adenomas for loss of mismatch repair protein expression to identify individuals with suspected Lynch syndrome. We tested 109 polyps from 69 proven mutation carriers (35 females and 34 males) belonging to 49 Lynch syndrome families. All polyps were tested by immunohistochemistry for four mismatch repair proteins MLH1, MSH2, MSH6 and PMS2. Detailed pathology review was performed by specialist gastrointestinal pathologists. The majority of polyps (86%) were conventional adenomas (n=94), with 65 tubular and 28 tubulovillous adenomas and a single villous adenoma. The remaining 15 lesions (14%) were serrated polyps. Overall, loss of mismatch repair expression was noted for 78/109 (72%) of polyps. Loss of mismatch repair expression was seen in 74 of 94 (79%) conventional adenomas, and 4 of 15 (27%) serrated polyps from mismatch repair gene mutation carriers. In all instances, loss of expression was consistent with the underlying germline mutation. Mismatch repair protein expression was lost in 27 of 29 adenomas with a villous component compared with 47 of 65 adenomas without this feature (93 vs73%; P=0.028). A strong trend was observed for high-grade dysplasia. Mismatch repair deficiency was observed in 12 of 12 conventional adenomas with high-grade dysplasia compared with 60 of 79 with low-grade dysplasia (100 vs76%; P=0.065). We were unable to demonstrate a significant association between conventional adenoma size or site and mismatch repair deficiency. All (4/4 or 100%) of the serrated polyps demonstrating mismatch repair deficiency were traditional serrated adenomas from a single family. Diagnostic testing of adenomas in suspected Lynch syndrome families is a useful alternative in cases where cancers are unavailable. The overwhelming majority of conventional adenomas from mutation carriers show loss of mismatch repair protein expression concordant with the underlying germline mutation.

In the two conditions juvenile polyps (JPs) and juvenile polyposis coli (JPC), colonic polyps may have overlapping histologic and phenotypic appearance, but JPC confers a significant risk for colon adenocarcinoma. Although not thought to contain adenomatous polyposis coli (APC) mutations, the status of ß-catenin and full-length APC protein expression in JPs is not known. We evaluated ß-catenin and full-length APC protein expression in JPs from children with JPs and JPC. Cases were identified through endoscopic procedure records. Immunohistochemistry was performed for ß-catenin and full-length APC protein. Loss of heterozygosity at the APC gene locus on chromosome 5 was assessed using two APC-linked microsatellite markers. Polyp and normal colonic tissue were analyzed from 36 children with JPs and 9 with JPC. Both APC and ß-catenin immunoreactivity were present in epithelial cells from all samples but in different patterns. In all normal colon and polyp samples, APC expression was cytoplasmic with maximal immunoreactivity in the goblet cells. In contrast, ß-catenin immunoreactivity in epithelial cells was limited to the plasma membrane in normal colon but was both cytoplasmic and nuclear in all 45 JPs. No evidence of APC gene loss of heterozygosity was found. In polyps from children with JPs and JPC, nuclear ß-catenin accumulation is a consistent feature, and it is not due to APC gene mutation or loss of full-length APC protein expression. Thus, ß-catenin accumulation may be intrinsic to the formation of juvenile-type polyps through an as-yet-undefined mechanism.

In the two conditions juvenile polyps (JPs) and juvenile polyposis coli (JPC), colonic polyps may have overlapping histologic and phenotypic appearance, but JPC confers a significant risk for colon adenocarcinoma. Although not thought to contain adenomatous polyposis coli (APC) mutations, the status of -catenin and full-length APC protein expression in JPs is not known. We evaluated -catenin and full-length APC protein expression in JPs from children with JPs and JPC. Cases were identified through endoscopic procedure records. Immunohistochemistry was performed for -catenin and full-length APC protein. Loss of heterozygosity at the APC gene locus on chromosome 5 was assessed using two APC-linked microsatellite markers. Polyp and normal colonic tissue were analyzed from 36 children with JPs and 9 with JPC. Both APC and -catenin immunoreactivity were present in epithelial cells from all samples but in different patterns. In all normal colon and polyp samples, APC expression was cytoplasmic with maximal immunoreactivity in the goblet cells. In contrast, -catenin immunoreactivity in epithelial cells was limited to the plasma membrane in normal colon but was both cytoplasmic and nuclear in all 45 JPs. No evidence of APC gene loss of heterozygosity was found. In polyps from children with JPs and JPC, nuclear -catenin accumulation is a consistent feature, and it is not due to APC gene mutation or loss of full-length APC protein expression. Thus, -catenin accumulation may be intrinsic to the formation of juvenile-type polyps through an as-yet-undefined mechanism.

Mutations of the APC gene are thought to be early events in the process of colorectal carcinogenesis. Although the complete function(s) of the APC gene product is not known, it has been shown that the APC protein interacts with β-catenin in a multi-protein complex to regulate the level of expression of β-catenin. Loss of normal APC protein function can lead to an accumulation of β-catenin in the cytosol and the nucleus. Immunohistochemical methods were used to determine the relationship between APC and β-catenin protein expression in human colonic tissues (150 normal, 9 hyperplastic, 58 adenomas and 83 carcinomas) and 12 paired samples of normal and cancer tissue in mouse colon. In all samples of normal human and mouse colonic mucosa and in human hyperplastic polyps both APC and β-catenin immunoreactivity were present in colonocytes. APC expression was cytoplasmic, with maximal immunoreactivity in the goblet cells. β-Catenin expression was predominantly localized to the plasma membrane, with no nuclear immunoreactivity. APC immunoreactivity was absent in all of the mouse adenocarcinomas and 83% of the human colon cancers. All of the human and mouse carcinomas had nuclear and cytoplasmic β-catenin expression. In contrast, only 29% of the 58 colonic adenomas were completely negative for APC immunoreactivity. Regardless of the presence or absence of APC, all of the adenomas had cytoplasmic and nuclear β-catenin immunoreactivity. Many colonic adenomas retain expression of full-length APC protein whereas it is usually lost in colorectal cancers. Regardless of the status of APC protein expression, β-catenin protein was found in the cytoplasm and nucleus of all neoplastic colonic mucosa. The dissociation between loss of expression of APC and accumulation of β-catenin in the nucleus suggests that inactivation of both alleles of the APC gene may not be required for β-catenin nuclear accumulation in colonic adenomas.

The clinical spectrum of symptomatic polyps and the frequency of familial polyposis is not well defined in children. In the present study, a series of children with juvenile polyposis coli (JPC) and non-JPC polyps were studied.

Gastrointest Endosc 1999;49:S50-9.

Summary Current procedures for isolating intestinal epithelial cell surface and intracellular membranes are based on the assumption that each organelle is marked by some unique constitutent. This assumption seemed inconsistent with the dynamic picture of subcellular organization emerging from studies of membrane turnover and recycling. Therefore, we have designed an alternative fractionation which is independent ofa priori marker assignments. We subjected mucosal homogenates to a sequence of separations based on sedimentation coefficient, equilibrium density, and partitioning in aqueous polymer twophase systems. The resulting distributions of protein and enzymatic markers define a total of 17 physically and biochemically distinct membrane populations. Among these are: basal-lateral membranes, with Na,K-ATPase enriched 21-fold; brush-border membranes, with alkaline phosphatase enriched as much as 38-fold; two populations apparently derived from the endoplasmic reticulum; a series of five populations believed to have been derived from the Golgi complex; and a series of five acid phosphatase-rich populations which we cannot identify unequivocally. Each of the five enzymatic markers we have followed is associated with a multiplicity of membrane populations. Basallateral, endoplasmic reticulum, and Golgi membranes contain alkaline phosphatase at the same specific activity as the initial homogenate. Similarly, Na,K-ATPase appears to be associated branes at specific activities two-to seven-fold that of the initial homogenate.

The primary function of the SC-pIg system is to secrete pIgs into various external secretions. The cellular mechanism responsible for this transport is schematically depicted in Figure 5. Polymeric immunoglobulin A, which is synthesized by plasma cells that are part of the mucosa-associated lymphoid tissue, gains access to the SC on the albuminal surface of epithelial cells by diffusion from sites of synthesis in mucosae or enters the blood circulation and is cleared, largely by hepatic transport, into bile. The pIgA binds to SC on the abluminal surface of the epithelial cells (and probably hepatocytes) initially by noncovalent interactions that are saturable, reversible, and specific for pIgA and IgM. Subsequently, covalent interaction between SC and its ligand occurs to a variable degree in different species. The SC-IgA complex is endocytosed by the epithelial cell or hepatocyte and is transported across the cell into the external secretions by a microtubule-dependent vesicular transport mechanism. At some point during the transport, the complex is rendered soluble by proteolytic cleavage of the membrane-associated SC molecule to release the soluble sIgA into the gland lumen or the canaliculus. In the intestinal lumen, SC helps protect the sIgA molecule from proteolytic degradation. The sIgA may play a major role in the mucosal defense against pathogenic organisms or harmful antigens.

Previously, we reported that two glycoproteins, carcinoembryonic antigen and secretory component, are preferentially expressed on the apical or laterobasal surfaces, respectively, of normal human colonic epithelial cells, whereas these antigens may be expressed over the entire cell surface of colonic cancer cells. These observations have prompted us to develop an animal model of aberrantly distributed normal surface antigens in colonic carcinoma. We prepared four monoclonal antibodies, three of which react specifically with antigens located on the microvillus surface and one that reacts specifically with the laterobasal surface of normal rat colonocytes. Three of the four cell-surface antigens were expressed by cells at all levels of the colonic crypt, but one of the microvillar antigens (p66) was expressed only on the mature colonocytes at the luminal surface. We then documented that a microvillus antigen (p66) detected by one of the antibodies and a laterobasal membrane antigen detected by another antibody were expressed over the entire surface of poorly differentiated colonic carcinoma cells induced by dimethylhydrazine. p66 was more often expressed on poorly differentiated colonic cancers than were the other three antigens. These observations indicate that (a) polarity of surface membrane antigens is a characteristic of normal rat colonic epithelial cells, (b) this polarity is not present in some experimental colonic carcinomas, and (c) the malignant phenotype of colonic carcinoma cells does not result merely from a block in normal differentiation of colonocytes.

We evaluated certain histochemical tests for their ability to detect premalignant mucosa in the dimethylhydrazine model of colonic carcinogenesis. Biweekly colonoscopic biopsies of the descending colon were performed for 29 wk in control and dimethylhydrazine-treated rats. Biopsy specimens of the splenic flexure, rectum, and any visualized tumors were taken. The specimens were stained with periodic acid-Schiff to detect neutral mucins, high-iron diamine alcian blue to detect sialylated and sulfated mucins, fluoresceinated peanut agglutinin, and fluoresceinated Ulex europeusagglutinin. None of the first three tests consistently detected premalignant mucosa. However, Ulex europeusagglutinin, which bound to only 3% of control biopsy specimens throughout the course of the study, bound to increasing numbers of biopsy specimens in the dimethylhydrazine-treated animals, reaching a maximum of 90% positivity by 13–16 wk. Moreover, Ulex europeusagglutinin bound strongly to all biopsy specimens from tissues adjacent to tumors and to 93% of tumors. Mucosal atrophy and focal dysplasia were present more frequently in specimens taken from the rectum (but not the splenic flexure) of dimethylhydrazine-treated animals than of control animals, but there was no correlation between the histochemical markers and either atrophy or dysplasia. We conclude that Ulex europeusagglutinin binding is a consistent feature of premalignant colonic mucosa in dimethylhydrazine-treated rats.

Proliferating cell nuclear antigen is expressed in cells from late G1 through the S-phase of the cell cycle. Therefore, antibodies directed against this molecule should provide a probe for labeling immunocytochemically the nuclei of proliferating cells. Herein we demonstrate the feasibility and reliability of this technique by quantifying immunostained pulmonary nuclei. We applied polyclonal and monoclonal antisera to alveolar and bronchiolar pulmonary epithelial cells in various proliferative states in tissue-sections and in vitro. A/J mice had a slightly higher labeling index than C57BL/6J mice, and proliferation in both strains increased dramatically after butylated hydroxytoluene treatment produced compensatory hyperplasia of Type-II pneumocytes. Immunostaining in fetal and neonatal lung samples from mice was higher than in adults. Spontaneous lung adenomas had a higher labeling index than the surrounding normal lung tissue. In addition, new data contained herein demonstrate a strain difference in proliferation of bronchiolar epithelial cells, and quantify the extent to which BHT-induced lung damage increases these proliferative rates. This mammalian nuclear antigen did not cross-react with antiserum to a functionally related bacterial protein, the beta subunit of E. coli DNA polymerase-III holoenzyme.

Olestra, a dietary fat substitute, was recently made available to consumers in savory snacks in three cities. Early reports of gastrointestinal complaints attributed to olestra attracted media coverage and fostered confusion among physicians and consumers about the nature of olestra and its effects on the digestive system. We reviewed all published studies of olestra's gastrointestinal effects and all relevant unpublished studies submitted to the Food and Drug Administration. Each study was analyzed by a group of expert gastroenterologists and epidemiologists. The symptoms reported with olestra ingestion are similar to those reported with ingestion of fiber and sorbitol, although the mechanisms involved in changing stool characteristics differ among these food additives. Olestra's effects on stool habit and characteristics are due to its presence in the stool. Large amounts are more likely to induce gastrointestinal symptoms than small amounts. There is no evidence that olestra induces pathological change in bowel function: there is no increased fluid or electrolyte nor is there altered gastrointestinal motility or microflora. Olestra and triglyceride ingestion resulted in a similar frequency of symptoms in normal adults and children and in people with chronic inflammatory bowel disease in remission. Olestra traverses the digestive tract intact to become a stool additive. Some subjects develop a change in bowel habit and stool characteristics due to the presence of more olestra in the stool. These changes resemble those associated with ingestion of sorbitol and fiber.

• Acid and gastrin production after pyloric-preserving pancreaticoduodenectomy was evaluated in six patients. Five patients had low-normal basal and stimulated acid output; the sixth patient was achlorhydric. Fasting gastrin levels were less than 90 to 105 pg/mL (normal range) in five patients, three of whom had stimulated gastrin levels that remained below this range. Two patients had stimulated gastrin levels of 510 pg/mL and 205 pg/mL, respectively, within 15 minutes of eating; however, both levels returned to normal by 120 minutes' time. The sixth patient had mildly elevated fasting (105 pg/mL) and stimulated gastrin levels (160 to 200 pg/mL) throughout the test period. The results suggest that pyloric-preserving pancreaticoduodenectomy does not lead to either gastric hyperacidity or persistent hypergastrinemia.(Arch Surg 1986;121:661-664)

The lectin peanut agglutinin binds to mucin secreted by neoplastic but not normal human colonic epithelial cells. Peanut agglutinin was found to bind to mucin secreted by experimentally induced neoplasms in the distal colons of CF-1 mice, but not in the distal colons of control animals. Serial examination of colonic tissues after exposure to carcinogen has revealed the “cancer-associated” mucin in histologically normal but potentially premalignant epithelium. Thus, in the chemical carcinogen-rodent model, a diffuse alteration in glycoprotein structure is found in that part of the murine colon that subsequently develops cancer, and this precedes the appearance of neoplastic tissue. Changes in mucin structure may prove to be useful in the identification of premalignant gastrointestinal epithelium in certain humans at high risk for colon cancer.

We have tried to identify a histochemical or immunohistochemical marker that would reliably detect mucosal dysplasia in chronic ulcerative colitis. Colonic biopsy specimens were taken from patients with long-standing ulcerative colitis undergoing surveillance colonoscopy. Control tissue was obtained from the margins of colonic resections performed for neoplastic or nonneoplastic diseases. Sections of the specimens were examined by periodic acid-Schiff staining, high iron diamine Alcian blue staining for sialomucins and sulfomucins, and binding of the lectins peanut agglutinin, Ulex europeusagglutinin I, and Ricinis communisI agglutinin. Sections were reacted also with anticarcinoembryonic antigen antibodies to determine whether a nonpolar surface distribution of the antigen was a feature of dysplasia. We found that changes in colonic mucin, characterized by periodic acid—Schiff-positive mucin outside of goblet cells, an increase in binding of peanut agglutinin, and an increase in the relative amount of sialylated mucin, were associated with morphologic dysplasia. However, identical alterations were observed, albeit less commonly, in colitis without dysplasia, particularly in the presence of active inflammation. No abnormality in the surface distribution of carcinoembryonic antigen or Ricinis communisI agglutinin was observed. Thus, we did not identify a reliable corollary test to the histologic diagnosis of mucosal dysplasia in ulcerative colitis. With regard to these histochemical markers, the colonic mucosa appears to respond similarly to inflammation and neoplasia.

The cellular and ultrastructural distribution of carcinoembryonic antigen and secretory component during differentiation of normal colonic epithelium and in colonic carcinomas was evaluated by peroxidase-labeled antibody immunocytochemistry. Carcinoembryonic antigen and secretory component were found to be markers of distinctly different stages of normal colonocyte differentiation. Whereas secretory component was expressed principally by proliferating absorptive cells in the midcrypt, carcioembryonic antigen expression was diminished in this crypt zone and was associated principally with mature columnar cells at the luminal surface and with undifferentiated cells at the crypt base. Carcinoembryonic antigen was preferentially expressed on the microvillar plasma membrane and secretory component on the basolateral plasma membrane in the normal colon. In 13 colon cancers studied, carcinoembryonic antigen was expressed on the entire surface of all the colon cancers except one anaplastic tumor, whereas secretory component was only expressed on five well or moderately differentiated cancers. These observations suggest that differentiation of colon cancers as assessed by morphology and phenotypic markers is not totally analogous to that found in the normal colon.

• Postirradiation "fixed" anorectal tumors are often considered incurable. Since 1980, we have carried out 12 pelvic and seven sacropelvic exenterations for this problem (adenocarcinoma, 18; squamous cancer, one). Nine tumors were primary; ten were recurrent (five after an anterior resection and five after an abdominoperineal resection). Prior irradiation ranged from 3000 to 12000 rad (30 to 120 Gy). Four patients had synchronous distant metastases; three died of disease (one with local recurrence), and the fourth patient has been living with disease (distant metastasis). Fifteen patients (four with B2 tumors and 11 with Astler-Coller C2 disease) had no extrapelvic disease. One patient died of postoperative complications; two others died free of disease. Three of the 15 patients died of disease (all with local recurrence), and one has been living with disease (local recurrence). Eight (53%) of 15 patients have been living free of disease 12+ to 53+ months. The results suggest that many patients with fixed postirradiation anorectal tumors may be salvaged by aggressive surgery.(Arch Surg 1987;122:537-541)

Summary Total renal ischemia for various time intervals (0–50) min) resulted in the rapid and duration-dependent redistribution of polarized membrane lipids and proteins in renal proximal tubule cells. Following only 15 min of ischemia, apical membrane enrichment of NaK-ATPase, normally a basolateral membrane (BLM) enzyme, had increased (1.6±0.6vs. 2.9±1.2,P<0.01). In vivo histochemical localization of NaK-ATPase showed reaction product throughout the apical microvillar region. PTH-stimulatable adenylate cyclase, another BLM protein, was also found in ischemic but not control apical membrane fractions. One dimensional SDS-PAGE showed four bands, present in control BLM and ischemic apical membranes, which could not be found in control apical membrane fractions. Immunohistochemical localization of leucine aminopeptidase (LAP) showed the enzyme was limited to the apical domain in control cells. Following ischemic injury (50 min), LAP staining could be seen within the cell and along the BLM. Following 24 hr of reperfusion, the BLM distribution of LAP was further enhanced. With cellular recovery from ischemic injury (5 days), LAP was again only visualized in the apical membrane. Duration-dependent alterations in apical and BLM lipids were also observed. Apical sphingomyelin and phosphatidylserine and the cholesterol-tophospholipid ratio decreased rapidly while apical phosphatidylcholine and phosphatidylinositol increased. Taken together, these results indicate renal ischemia causes rapid duration-dependent reversible loss of surface membrane polarity in proximal tubule cells.

Expression of the proliferating cell nuclear antigen (PCNA) was examined in normal rat intestinal tissues and in carcinogen-treated nonneoplastic and neoplastic colonic mucosa. In the normal intestine, PCNA expression was confined to the expected region of the proliferative compartment. A strong correlation was observed between PCNA labeling index and both [3H]thymidine labeling index (R= 0.993, P= 0.007) and percent of cells in S phase as determined by flow cytometry (R= 0.982, P= 0.018) and between the location of the maximal staining for PCNA and [3H]thymidine (R= 0.997, P< 0.05). In animals treated with dimethylhydrazine (DMH), crypt hyperplasia, an increased PCNA labeling index, and shifts in both the region of maximal and the upper extent of PCNA expression were observed during DMH exposure; significant crypt hyperplasia and expansion of the PCNA-positive compartment persisted after completion of DMH injections. The patterns of PCNA expression and bromodeoxyuridine incorporation were similar in DMH-induced tumors. It is concluded that PCNA immunohistochemistry can be used as a reliable marker of the proliferative compartment in both normal and neoplastic colonic mucosa.

Aim:The National Colorectal Cancer Roundtable convened a national Summit to discuss the causes of early-onset colorectal cancer and clinical challenges to mitigating burden of this disease. Materials & methods:Information presented was synthesized through scientific consensus building to determine priorities for new research and practice change. Results:Research priorities include evaluating role of novel risk factors, understanding natural history and identifying ways to implement evidenced-based practices for identifying and managing at-risk persons. Practice change should focus on adoption of guidelines for collecting family history, screening in young adults at risk, provider and population awareness about risk and symptoms, and universal tumor testing. Conclusion:Successful implementation of strategies to address research and practice change will require collaboration from multiple partners.