Eflornithine plus Sulindac for Prevention of Progression in Familial Adenomatous Polyposis.

BACKGROUND: The efficacy and safety of combination therapy with eflornithine and sulindac, as compared with either drug alone, in delaying disease progression in patients with familial adenomatous polyposis are unknown. METHODS: We evaluated the efficacy and safety of the combination of eflornithine and sulindac, as compared with either drug alone, in adults with familial adenomatous polyposis. The patients were stratified on the basis of anatomical site with the highest polyp burden and surgical status; the strata were precolectomy (shortest projected time to disease progression), rectal or ileal pouch polyposis after colectomy (longest projected time), and duodenal polyposis (intermediate projected time). The patients were then randomly assigned in a 1:1:1 ratio to receive 750 mg of eflornithine, 150 mg of sulindac, or both once daily for up to 48 months. The primary end point, assessed in a time-to-event analysis, was disease progression, defined as a composite of major surgery, endoscopic excision of advanced adenomas, diagnosis of high-grade dysplasia in the rectum or pouch, or progression of duodenal disease. RESULTS: A total of 171 patients underwent randomization. Disease progression occurred in 18 of 56 patients (32%) in the eflornithine-sulindac group, 22 of 58 (38%) in the sulindac group, and 23 of 57 (40%) in the eflornithine group, with a hazard ratio of 0.71 (95% confidence interval [CI], 0.39 to 1.32) for eflornithine-sulindac as compared with sulindac (P = 0.29) and 0.66 (95% CI, 0.36 to 1.24) for eflornithine-sulindac as compared with eflornithine. Among 37 precolectomy patients, the corresponding values in the treatment groups were 2 of 12 patients (17%), 6 of 13 (46%), and 5 of 12 (42%) (hazard ratios, 0.30 [95% CI, 0.07 to 1.32] and 0.20 [95% CI, 0.03 to 1.32]); among 34 patients with rectal or ileal pouch polyposis, the values were 4 of 11 patients (36%), 2 of 11 (18%), and 5 of 12 (42%) (hazard ratios, 2.03 [95% CI, 0.43 to 9.62] and 0.84 [95% CI, 0.24 to 2.90]); and among 100 patients with duodenal polyposis, the values were 12 of 33 patients (36%), 14 of 34 (41%), and 13 of 33 (39%) (hazard ratios, 0.73 [95% CI, 0.34 to 1.52] and 0.76 [95% CI, 0.35 to 1.64]). Adverse and serious adverse events were similar across the treatment groups. CONCLUSIONS: In this trial involving patients with familial adenomatous polyposis, the incidence of disease progression was not significantly lower with the combination of eflornithine and sulindac than with either drug alone. (Funded by Cancer Prevention Pharmaceuticals; ClinicalTrials.gov number, NCT01483144; EudraCT number, 2012-000427-41.).

Anal Adenocarcinoma: A Rare Entity in Need of Multidisciplinary Management.

BACKGROUND: Anal adenocarcinoma is a rare clinical entity for which the optimal management is not defined. OBJECTIVE: This study aimed to describe the multidisciplinary management and outcomes of patients with anal adenocarcinoma. DESIGN: This is a retrospective cohort study. SETTING: This study was conducted at a quaternary cancer center. PATIENTS: Men and women with anal adenocarcinoma treated between 1995 and 2016 were selected. INTERVENTIONS: Fifty-two patients were treated with either chemoradiotherapy or trimodality therapy including radiation therapy, chemotherapy, and surgical resection. MAIN OUTCOME MEASURES: Local failure, regional failure, and distant metastasis rates were estimated using the cumulative incidence method. The Kaplan-Meier method was used to estimate progression-free survival and overall survival. The multivariable Cox proportional hazards model was used to evaluate the clinical predictors of outcome. RESULTS: There was a higher 5-year rate of local failure in patients treated with chemoradiotherapy compared with trimodality therapy (53% vs 10%; p < 0.01). The 5-year incidence of distant metastases was 29% (trimodality therapy) versus 30% (chemoradiotherapy; p = 0.9); adjuvant chemotherapy did not reduce the incidence of distant metastases (p = 0.8). Five-year overall survival was 73% (trimodality therapy) versus 49.4% (chemoradiotherapy; p = 0.1). On multivariable analysis, factors associated with worse overall survival were treatment with chemoradiotherapy, cT3-4 category disease, and node-positive disease. LIMITATIONS: This study is limited by its small sample size and retrospective nature. CONCLUSIONS: Although treatment may continue to be tailored to individual patients, better outcomes with a trimodality therapy approach were observed. See Video Abstract at http://links.lww.com/DCR/B708.ADENOCARCINOMA ANAL: UNA ENTIDAD POCO FRECUENTE EN NECESIDAD DE UN MANEJO MULTIDISCIPLINARIO. ANTECEDENTES: El adenocarcinoma anal es una entidad clínica poco frecuente por lo que aún no se define el manejo óptimo. OBJETIVO: Describir el manejo multidisciplinario y los resultados de los pacientes con adenocarcinoma anal. DISEO: Estudio de cohorte retrospectivo. ENTORNO CLINICO: Centro de cáncer cuaternario. PACIENTES: Hombres y mujeres con adenocarcinoma anal tratados entre 1995 y 2016. INTERVENCIONES: Cincuenta y dos pacientes fueron tratados con quimiorradioterapia o terapia trimodal que incluyó: radioterapia, quimioterapia y resección quirúrgica. PRINCIPALES MEDIDAS DE VALORACION: Se estimaron las tasas de falla local, falla regional y metástasis a distancia mediante el método de incidencia acumulada. Se utilizó el método de Kaplan-Meier para estimar la supervivencia libre de progresión y la supervivencia global. Los riesgos proporcionales de multivariable Cox se utilizaron para evaluar los predictores clínicos de los resultados. RESULTADOS: Hubo una mayor tasa de falla local a cinco años en pacientes tratados con quimiorradioterapia en comparación con terapia trimodal (53% vs 10%; p < 0,01). La incidencia a cinco años de metástasis a distancia fue del 29% (terapia trimodal) versus 30% (quimiorradioterapia) (p = 0,9); la quimioterapia adyuvante no redujo la incidencia de metástasis a distancia (p = 0,8). La supervivencia global a cinco años fue del 73% (terapia trimodal) versus 49,4% (quimiorradioterapia); p = 0,1. En el análisis multivariable, los factores asociados con una peor supervivencia general fueron el tratamiento con quimiorradioterapia, enfermedad de categoría cT3-4 y enfermedad con ganglios positivos. LIMITACIONES: Este estudio está limitado por su pequeño tamaño de muestra y su naturaleza retrospectiva. CONCLUSIONES: Aunque el tratamiento puede seguir adaptándose a pacientes individuales, se observaron mejores resultados con un enfoque TTM. Conslute Video Resumen en http://links.lww.com/DCR/B708. (Traducción- Dr. Francisco M. Abarca-Rendon).

Cost-effectiveness of Active Identification and Subsequent Colonoscopy Surveillance of Lynch Syndrome Cases.

BACKGROUND & AIMS: The province of Ontario, Canada is considering immunohistochemical followed by cascade analyses of all patients who received a diagnosis of colorectal cancer (CRC) at an age younger than 70 years to identify individuals with Lynch syndrome. We evaluated the costs and benefits of testing for Lynch syndrome and determined the optimal surveillance interval for first-degree relatives (FDRs) found to have Lynch syndrome. METHODS: We developed a patient flow diagram to determine costs and yield of immunohistochemical testing for Lynch syndrome in CRC cases and, for those found to have Lynch syndrome, their FDRs, accounting for realistic uptake. Subsequently, we used the MISCAN-colon model to compare costs and benefits of annual, biennial, and triennial surveillance in FDRs identified with Lynch syndrome vs colonoscopy screening every 10 years (usual care for individuals without a diagnosis of Lynch syndrome). RESULTS: Testing 1000 CRC cases was estimated to identify 20 CRC index cases and 29 FDRs with Lynch syndrome at a cost of $310,274. Despite the high cost of Lynch syndrome tests, offering the FDRs with Lynch syndrome biennial colonoscopy surveillance was cost-effective at $8785 per life-year gained compared with usual care because of a substantial increase in life-years gained (+122%) and cost savings in CRC care. Triennial surveillance was more costly and less effective, and annual surveillance showed limited additional benefit compared with biennial surveillance. CONCLUSIONS: Immunohistochemical testing for Lynch syndrome in persons younger than 70 years who received a diagnosis of CRC and then testing FDRs of those found to have Lynch syndrome provide a good balance between costs and long-term benefits. Colonoscopy surveillance every 2 years is the optimal surveillance interval for patients with Lynch syndrome.

High prevalence of adenomatous colorectal polyps in young cancer survivors treated with abdominal radiation therapy: results of a prospective trial.

OBJECTIVE: Cancer survivors treated with abdominal/pelvic radiation therapy (ART) have increased the risks of colorectal cancer (CRC), although evidence supporting early CRC screening for these patients is lacking. We sought to determine whether there is an elevated prevalence of adenomatous colorectal polyps in young survivors prior to the age when screening would be routinely recommended. DESIGN: We conducted a prospective study of early colonoscopic screening in cancer survivors aged 35-49 who had received ART ≥10 years previously. The planned sample size was based on prior studies reporting a prevalence of adenomatous polyps of approximately 20% among the average-risk population ≥50 years of age, in contrast to ≤10% among those average-risk people aged 40-50 years, for whom screening is not routinely recommended. RESULTS: Colonoscopy was performed in 54 survivors, at a median age of 45 years (range 36-49) and after median interval from radiation treatment of 19 years (10.6-43.5). Forty-nine polyps were detected in 24 patients, with 15 patients (27.8%; 95% CI 17.6% to 40.9%) having potentially precancerous polyps. Fifty-three per cent of polyps were within or at the edge of the prior ART fields. CONCLUSIONS: Young survivors treated with ART have a polyp prevalence comparable with the average-risk population aged ≥50 years and substantially higher than previously reported for the average-risk population aged 40-50 years. These findings lend support to the early initiation of screening in these survivors. CLINICAL TRIAL REGISTRATION NUMBER: NCT00982059; results.

DNA Mismatch Repair Status Predicts Need for Future Colorectal Surgery for Metachronous Neoplasms in Young Individuals Undergoing Colorectal Cancer Resection.

BACKGROUND: The treatment of colorectal cancer in young patients involves both management of the incident cancer and consideration of the possibility of Lynch syndrome and the development of metachronous colorectal cancers. OBJECTIVE: This study aims to assess the prognostic role of DNA mismatch repair deficiency and extended colorectal resection for metachronous colorectal neoplasia risk in young patients with colorectal cancer. DESIGN, SETTING, AND PATIENTS: This is a retrospective review of 285 patients identified in our GI cancer registry with colorectal cancer diagnosed at 35 years or younger in the absence of polyposis. MAIN OUTCOME MEASURES: Using univariate and multivariate analysis, we assessed the prognostic role of mismatch repair deficiency and standard clinicopathologic characteristics, including the extent of resection, on the rate of developing metachronous colorectal neoplasia requiring resection. RESULTS: Mismatch repair deficiency was identified in biospecimens from 44% of patients and was significantly associated with an increased risk for metachronous colorectal neoplasia requiring resection (10-year cumulative risk, 13.5% ± 4.2%) compared with 56% of patients with mismatch repair-intact colorectal cancer (10-year cumulative risk, 5.8% ± 3.3%; p = 0.011). In multivariate analysis, mismatch repair deficiency was associated with a HR of 3.65 (95% CI, 1.44-9.21; p = 0.006) for metachronous colorectal neoplasia, whereas extended resection with ileorectal or ileosigmoid anastomosis significantly decreased the risk of metachronous colorectal neoplasia (HR, 0.21; 95% CI, 0.05-0.90; p = 0.036). LIMITATIONS: This study had a retrospective design, and, therefore, recommendations for colorectal cancer surgery and screening were not fully standardized. Quality of life after colorectal cancer surgery was not assessed. CONCLUSIONS: Young patients with colorectal cancer with molecular hallmarks of Lynch syndrome were at significantly higher risk for the development of subsequent colorectal neoplasia. This risk was significantly reduced in those who underwent extended resection compared with segmental resection.

Identification of genes expressed by immune cells of the colon that are regulated by colorectal cancer-associated variants.

A locus on human chromosome 11q23 tagged by marker rs3802842 was associated with colorectal cancer (CRC) in a genome-wide association study; this finding has been replicated in case-control studies worldwide. In order to identify biologic factors at this locus that are related to the etiopathology of CRC, we used microarray-based target selection methods, coupled to next-generation sequencing, to study 103 kb at the 11q23 locus. We genotyped 369 putative variants from 1,030 patients with CRC (cases) and 1,061 individuals without CRC (controls) from the Ontario Familial Colorectal Cancer Registry. Two previously uncharacterized genes, COLCA1 and COLCA2, were found to be co-regulated genes that are transcribed from opposite strands. Expression levels of COLCA1 and COLCA2 transcripts correlate with rs3802842 genotypes. In colon tissues, COLCA1 co-localizes with crystalloid granules of eosinophils and granular organelles of mast cells, neutrophils, macrophages, dendritic cells and differentiated myeloid-derived cell lines. COLCA2 is present in the cytoplasm of normal epithelial, immune and other cell lineages, as well as tumor cells. Tissue microarray analysis demonstrates the association of rs3802842 with lymphocyte density in the lamina propria (p = 0.014) and levels of COLCA1 in the lamina propria (p = 0.00016) and COLCA2 (tumor cells, p = 0.0041 and lamina propria, p = 6 × 10(-5)). In conclusion, genetic, expression and immunohistochemical data implicate COLCA1 and COLCA2 in the pathogenesis of colon cancer. Histologic analyses indicate the involvement of immune pathways.

Proctocolectomy for colorectal cancer--is the ileal pouch anal anastomosis a safe alternative to permanent ileostomy?

PURPOSE: Ileal pouch anal anastomosis (IPAA) is the procedure of choice in patients requiring surgery for ulcerative colitis (UC) and familial adenomatous polyposis (FAP). There are few data on reconstruction with the IPAA in patients with colorectal cancer (CRC). This study assessed the outcomes of the IPAA compared to proctocolectomy and permanent ileostomy (PI) on these patients. METHODS: Between 1983 and 2013, over 2800 patients with CRC have been treated at the Mount Sinai Hospital (MSH). Demographic, surgical, pathological, and outcome data for all patients have been maintained in a database-73 patients were treated for CRC with proctocolectomy: 39 patients with IPAA and 34 patients with PI. Clinical features, pathologic findings, and survival outcomes were compared between these groups. RESULTS: Each group was similar with respect to gender, stage, and histologic grade. Patients undergoing IPAA were significantly younger. The diagnosis leading to proctocolectomy was more commonly UC or FAP in patients treated with IPAA (39/39 vs. 23/34, p = 0.001). Rectal cancer subgroups were similar in age, sex, TNM stage, T-stage, height of tumor, and histologic grade. There was no significant difference in overall or disease free survival between groups for colon or rectal primaries. Analysis using the Cochran-Armitage trend test suggests that utilization of IPAA has increased over time (p = 0.002). CONCLUSIONS: The IPAA is a viable and safe option to select for patients who would otherwise require PI. Increased experience and improved outcomes following IPAA has led to its more liberal use in selected patients.

Integrated analysis of genome-wide copy number alterations and gene expression in microsatellite stable, CpG island methylator phenotype-negative colon cancer.

Microsatellite stable (MSS), CpG island methylator phenotype (CIMP)-negative colorectal tumors, the most prevalent molecular subtype of colorectal cancer, are associated with extensive copy number alteration (CNA) events and aneuploidy. We report on the identification of characteristic recurrent CNA (with frequency >25%) events and associated gene expression profiles for a total of 40 paired tumor and adjacent normal colon tissues using genome-wide microarrays. We observed recurrent CNAs, namely gains at 1q, 7p, 7q, 8p12-11, 8q, 12p13, 13q, 20p, 20q, Xp, and Xq and losses at 1p36, 1p31, 1p21, 4p15-12, 4q12-35, 5q21-22, 6q26, 8p, 14q, 15q11-12, 17p, 18p, 18q, 21q21-22, and 22q. Within these genomic regions we identified 356 genes with significant differential expression (P < 0.0001 and ±1.5-fold change) in the tumor compared to adjacent normal tissue. Gene ontology and pathway analyses indicated that many of these genes were involved in functional mechanisms that regulate cell cycle, cell death, and metabolism. An amplicon present in >70% of the tumor samples at 20q11-20q13 contained several cancer-related genes (AHCY, POFUT1, RPN2, TH1L, and PRPF6) that were upregulated and demonstrated a significant linear correlation (P < 0.05) for gene dosage and gene expression. Copy number loss at 8p, a CNA associated with adenocarcinoma and poor prognosis, was observed in >50% of the tumor samples and demonstrated a significant linear correlation for gene dosage and gene expression for two potential tumor suppressor genes, MTUS1 (8p22) and PPP2CB (8p12). The results from our integration analysis illustrate the complex relationship between genomic alterations and gene expression in colon cancer.

Colon and rectal cancer survival by tumor location and microsatellite instability: the Colon Cancer Family Registry.

BACKGROUND: Cancers in the proximal colon, distal colon, and rectum are frequently studied together; however, there are biological differences in cancers across these sites, particularly in the prevalence of microsatellite instability. OBJECTIVE: We assessed the differences in survival by colon or rectal cancer site, considering the contribution of microsatellite instability to such differences. DESIGN: This is a population-based prospective cohort study for cancer survival. SETTINGS: This study was conducted within the Colon Cancer Family Registry, an international consortium. Participants were identified from population-based cancer registries in the United States, Canada, and Australia. PATIENTS: Information on tumor site, microsatellite instability, and survival after diagnosis was available for 3284 men and women diagnosed with incident invasive colon or rectal cancer between 1997 and 2002, with ages at diagnosis ranging from 18 to 74. MAIN OUTCOME MEASURES: Cox regression was used to calculate hazard ratios for the association between all-cause mortality and tumor location, overall and by microsatellite instability status. RESULTS: Distal colon (HR, 0.59; 95% CI, 0.49-0.71) and rectal cancers (HR, 0.68; 95% CI, 0.57-0.81) were associated with lower mortality than proximal colon cancer overall. Compared specifically with patients with proximal colon cancer exhibiting no/low microsatellite instability, patients with distal colon and rectal cancers experienced lower mortality, regardless of microsatellite instability status; patients with proximal colon cancer exhibiting high microsatellite instability had the lowest mortality. LIMITATIONS: Study limitations include the absence of stage at diagnosis and cause-of-death information for all but a subset of study participants. Some patient groups defined jointly by tumor site and microsatellite instability status are subject to small numbers. CONCLUSION: Proximal colon cancer survival differs from survival for distal colon and rectal cancer in a manner apparently dependent on microsatellite instability status. These findings support the premise that proximal colon, distal colon, and rectal cancers are clinicopathologically distinct.

Evaluating colonoscopy screening intervals in patients with Lynch syndrome from a large Canadian registry.

BACKGROUND: Lynch syndrome (LS) screening guidelines originally recommended colonoscopy every 1 to 2 years, beginning between the ages of 20 and 25 years. Recent studies have questioned the benefits of these short screening intervals in preventing colorectal cancer (CRC). Our goal is to determine how colonoscopy screening intervals impact CRC in patients with LS. METHODS: We analyzed the demographics, screening practices, and outcomes of patients with LS identified through the clinic based Familial Gastrointestinal Cancer Registry at the Zane Cohen Centre, Sinai Health System, Toronto, Canada. RESULTS: A total of 429 patients with LS were identified with median follow-up of 9.2 years; 44 developed CRC. We found a positive trend between shorter screening intervals and the number of adenomas detected during colonoscopy. Any new adenoma detected at screening decreased 10-year CRC incidence by 11.3%. For MLH1 carriers, a screening interval of 1-2 years vs 2-3 years led to a 20-year cumulative CRC risk reduction of 28% and 14% in females and males, respectively. For MSH2 carriers, this risk reduction was 29% and 17%, respectively, and for male MSH6 carriers 18%. Individuals without any adenomas detected (53.4% of LS carriers) had an increased 20-year CRC risk of 25.7% and 57.2% for women and men, respectively, compared with those diagnosed with adenomas at screening. CONCLUSIONS: The recommended colonoscopy screening interval of 1-2 years is efficient at detecting adenomas and reducing CRC risk. The observation that 53.4% of LS patients never had an adenoma warrants further investigation about a possible adenoma-free pathway.

Limiting oxidative DNA damage reduces microbe-induced colitis-associated colorectal cancer.

Inflammatory bowel disease patients have a greatly increased risk of developing colitis-associated colon cancer (CAC); however, the basis for inflammation-induced genetic damage requisite for neoplasia is unclear. Using three models of CAC, we find that sustained inflammation triggers 8-oxoguanine DNA lesions. Strikingly, antioxidants or iNOS inhibitors reduce 8-oxoguanine and polyps in CAC models. Because the mismatch repair (MMR) system repairs 8-oxoguanine and is frequently defective in colorectal cancer (CRC), we test whether 8-oxoguanine mediates oncogenesis in a Lynch syndrome (MMR-deficient) model. We show that microbiota generates an accumulation of 8-oxoguanine lesions in MMR-deficient colons. Accordingly, we find that 8-oxoguanine is elevated in neoplastic tissue of Lynch syndrome patients compared to matched untransformed tissue or non-Lynch syndrome neoplastic tissue. While antioxidants reduce 8-oxoguanine, they do not reduce CRC in Lynch syndrome models. Hence, microbe-induced oxidative/nitrosative DNA damage play causative roles in inflammatory CRC models, but not in Lynch syndrome models.

Concordance with clinical practice guidelines for adjuvant chemotherapy in patients with stage I-III colon cancer: experience in 2 Canadian provinces.

BACKGROUND: Clinical practice guidelines (CPGs) for the adjuvant treatment of colorectal cancer were published by the National Institutes of Health in 1991. The American Society of Clinical Oncology and Cancer Care Ontario have recommended adjuvant chemotherapy for patients with high-risk stage II colon cancer. We evaluated differences in concordance with guidelines in the treatment of patients with stage I-III colon cancer in the Canadian provinces of Newfoundland and Labrador and Ontario. METHODS: We assessed clinical data and treatment from January 1999 to December 2000 for 130 patients from Newfoundland and Labrador and 315 patients from Ontario who had stage I-III colon cancer. The primary outcome was concordance with guidelines for adjuvant treatment. We evaluated factors affecting the use of chemotherapy in patients with stage II disease. RESULTS: No patients received adjuvant therapy for stage I disease. Forty-five of 52 patients (87%) in Newfoundland and Labrador and 108 of 115 patients (94%) in Ontario received adjuvant chemotherapy for stage III colon cancer. Twenty of 55 patients (36%) in Newfoundland and Labrador and 44 of 116 patients (38%) in Ontario received adjuvant therapy for stage II disease. Eighteen of 41 patients (44%) in Newfoundland and Labrador and 30 of 53 patients (57%) in Ontario with high-risk features received adjuvant treatment, which was significantly higher than patients without high-risk features. There was a strong trend toward using chemotherapy in patients with stage II disease who were 50 years or younger, independent of high-risk status. CONCLUSION: Concordance with CPGs for adjuvant chemotherapy in patients with stage II colon cancer was not optimal. This may reflect selection bias among referring surgeons, a paucity of level-I evidence and the belief that other factors such as age may play a role in predicting outcome.

Transcriptional cooperation between the transforming growth factor-beta and Wnt pathways in mammary and intestinal tumorigenesis.

Transforming growth factor-beta (TGF-beta) and Wnt ligands function in numerous developmental processes, and alterations of both signaling pathways are associated with common pathologic conditions, including cancer. To obtain insight into the extent of interdependence of the two signaling cascades in regulating biological responses, we used an oligonucleotide microarray approach to identify Wnt and TGF-beta target genes using normal murine mammary gland epithelial cells as a model. Combination treatment of TGF-beta and Wnt revealed a novel transcriptional program that could not have been predicted from single ligand treatments and included a cohort of genes that were cooperatively induced by both pathways. These included both novel and known components or modulators of TGF-beta and Wnt pathways, suggesting that mutual feedback is a feature of the coordinated activities of the ligands. The majority of the cooperative targets display increased expression in tumors derived from either Min (many intestinal neoplasia) or mouse mammary tumor virus (MMTV)-Wnt1 mice, two models of Wnt-induced tumors, with nine of these genes (Ankrd1, Ccnd1, Ctgf, Gpc1, Hs6st2, IL11, Inhba, Mmp14, and Robo1) showing increases in both. Reduction of TGF-beta signaling by expression of a dominant-negative TGF-beta type II receptor in bigenic MMTV-Wnt1/DNIIR mice increased mammary tumor latency and was correlated with a decrease in expression of Gpc1, Inhba, and Robo1, three of the TGF-beta/Wnt cooperative targets. Our results indicate that the TGF-beta and Wnt/beta-catenin pathways are firmly intertwined and generate a unique gene expression pattern that can contribute to tumor progression.

Missense polymorphisms in the adenomatous polyposis coli gene and colorectal cancer risk.

PURPOSE: Whereas truncating germline mutations of the adenomatous polyposis coli (APC) gene give rise to familial adenomatous polyposis, missense polymorphisms of APC may confer a weaker risk for colorectal cancer. METHODS: We sequenced the entire open reading frame of the APC gene and tested for two common MYH mutations in a population-based series of patients with colorectal cancer and 5 to 99 adenomas. Missense adenomatous polyposis coli alterations identified in this colorectal cancer multiple-polyp population were analyzed in a population-based series of patients with colorectal cancer and healthy control subjects. RESULTS: Germline APC or mutY human homologue (MYH) alterations were identified in 16 of 39 colorectal cancer-multiple polyp patients. Four missense APC gene alterations (S130G, E1317Q, D1822V, G2502S) were observed in 13 individuals and 3 additional patients carried presumed pathogenic (APC Y94X, biallelic MYH Y165C and heterozygous MYH G382D) mutations. When independently assessed in 971 patients with colorectal cancer and 954 healthy control subjects, none of the identified missense APC alterations conferred a significantly increased risk for colorectal cancer, odds ratio (95 percent confidence intervals): S130G = 3.1 (0.29-32.25), E1317Q = 1.08 (0.59-2.74), G2502S = 1 (0.65-1.63), D1822V (heterozygous) = 0.79 (0.64-0.98), D1822V (homozygous) = 0.82 (0.63-1.27). CONCLUSIONS: Germline missense APC alterations observed in 33 percent of patients with multiple colorectal neoplasms seemed to play a limited role in colorectal cancer risk when independently assessed by a population-based, case-control analysis.

Tumor microsatellite-instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for colon cancer.

BACKGROUND: Colon cancers with high-frequency microsatellite instability have clinical and pathological features that distinguish them from microsatellite-stable tumors. We investigated the usefulness of microsatellite-instability status as a predictor of the benefit of adjuvant chemotherapy with fluorouracil in stage II and stage III colon cancer. METHODS: Tumor specimens were collected from patients with colon cancer who were enrolled in randomized trials of fluorouracil-based adjuvant chemotherapy. Microsatellite instability was assessed with the use of mononucleotide and dinucleotide markers. RESULTS: Of 570 tissue specimens, 95 (16.7 percent) exhibited high-frequency microsatellite instability. Among 287 patients who did not receive adjuvant therapy, those with tumors displaying high-frequency microsatellite instability had a better five-year rate of overall survival than patients with tumors exhibiting microsatellite stability or low-frequency instability (hazard ratio for death, 0.31 [95 percent confidence interval, 0.14 to 0.72]; P=0.004). Among patients who received adjuvant chemotherapy, high-frequency microsatellite instability was not correlated with increased overall survival (hazard ratio for death, 1.07 [95 percent confidence interval, 0.62 to 1.86]; P=0.80). The benefit of treatment differed significantly according to the microsatellite-instability status (P=0.01). Adjuvant chemotherapy improved overall survival among patients with microsatellite-stable tumors or tumors exhibiting low-frequency microsatellite instability, according to a multivariate analysis adjusted for stage and grade (hazard ratio for death, 0.72 [95 percent confidence interval, 0.53 to 0.99]; P=0.04). By contrast, there was no benefit of adjuvant chemotherapy in the group with high-frequency microsatellite instability. CONCLUSIONS: Fluorouracil-based adjuvant chemotherapy benefited patients with stage II or stage III colon cancer with microsatellite-stable tumors or tumors exhibiting low-frequency microsatellite instability but not those with tumors exhibiting high-frequency microsatellite instability.

Clinical implications of our advancing knowledge of colorectal cancer genetics: inherited syndromes, prognosis, prevention, screening and therapeutics.

Recent genetic advances in our knowledge of colorectal cancer genetics are beginning to pay translational dividends in the management of this common clinical problem. We are now able to accurately screen and counsel individuals at risk of rare inherited cancer syndromes. We have recently introduced two of what are sure to be numerous biologic-based therapies, and have shown that colorectal neoplasia risk can be modestly reduced by various chemopreventative agents. Finally, our advancing knowledge has led to significant inroads into understanding what genetic alterations define prognosis and predict response to specific chemotherapeutic agents, and we are beginning to explore the utility of this knowledge in mass genetic-based clinical screening efforts. Enthusiasm must be tempered, however, by the extraordinary cost that often accompanies relatively modest gains. Finally, although genetic-based therapy often receives the greatest attention, molecular genetics, will likely have the greatest cost-effective impact in primary prevention and early diagnosis.

Mutation profiling of mismatch repair-deficient colorectal cncers using an in silico genome scan to identify coding microsatellites.

Human colorectal, endometrial, and gastric cancers with defective DNA mismatch repair (MMR) have microsatellite instability, a unique molecular alteration characterized by widespread frameshift mutations of repetitive DNA sequences. We developed "Kangaroo," a bioinformatics program for searches in nucleotide and protein sequence databases, and performed an in silico genome scan for DNA coding microsatellites that may have novel mutations in MMR-deficient cancers. Examination of 29 previously untested coding polyadenines revealed widespread mutations in MMR-deficient colorectal cancers, with the highest frequencies in ERCC5, CASP8AP2, p72, RAD50, CDC25, RECQL1, CBF2, RACK7, GRK4, and DNAPK (range, 10-33%). This algorithm allows comprehensive mutation profiling of MMR-deficient cancers, an important step in understanding the pathogenesis of these neoplasms.

Heterozygosity for the BLM(Ash) mutation and cancer risk.

Bloom syndrome is an autosomal recessive disorder whose characteristics include an increased risk for many types of cancers. In contrast to the homozygous mutations of Bloom syndrome, heterozygous carriers of BLM mutations may be at increased risk for developing colorectal cancer. We have screened 2,333 Jewish individuals, including 497 individuals with colorectal cancer, 125 with adenomatous polyps, 767 with noncolorectal cancers and 944 controls for the truncating BLM(Ash) founder mutation. The BLM(Ash) mutation was carried by 0.80% of individuals with colorectal neoplasia, 0.87% of those with any type of cancer and 0.85% of controls. In addition to case-control data, we found no evidence to support a significant relationship between increased cancer risk and heterozygous BLM(Ash) mutations with respect to age of cancer diagnosis, tumor multiplicity or family cancer history.

Chromosome 7q31 allelic imbalance and somatic mutations of RAY1/ST7 gene in colorectal cancer.

ST7 is a putative tumor suppressor gene on chromosome 7q31. However, the role of ST7 as a tumor suppressor is uncertain as somatic mutations have been difficult to demonstrate. In order to investigate the genetic role of RAY1/ST7 in tumorigenesis, we have screened 135 colorectal cancers for loss of heterozygosity (LOH) at chromosome 7q31. The entire RAY1/ST7 gene, including intron/exon boundaries and alternate 5' and 3' sequences of 15/124 (12%) informative cancers with LOH were characterized. No somatic mutations of the RAY1/ST7 gene were observed. Our results do not support a role for RAY1/ST7 as a colorectal cancer tumor suppressor gene.

Prognostic factors in resected pancreatic adenocarcinoma: analysis of actual 5-year survivors.

BACKGROUND: Pancreatic cancer is a rapidly fatal disease with very few 5-year survivors even after aggressive surgical treatment. Our objective was to determine the actual 5-year survival rate of patients with pancreatic adenocarcinoma who underwent a resection with curative intent in 5 teaching hospitals within the University of Toronto system. We then sought to determine clinical and histopathologic features of 5-year survivors to determine factors associated with a favorable prognosis. STUDY DESIGN: A retrospective chart review was performed using surgeon and hospital databases to identify patients who had a surgical resection for pancreatic adenocarcinoma between January 1, 1988, and December 31, 1996. RESULTS: One hundred twenty-three patients who had a resection and a pathologic diagnosis of pancreatic adenocarcinoma with complete followup were identified from seven surgical practices. Mean survival (+/- standard error) in this series was 31.7 +/- 3.5 months (median 13.6 months). There were 18 5-year survivors (14.6%), including 5 patients (4.1%) who survived longer than 10 years. The survivors included 13 patients who had undergone a Whipple resection, 4 who had undergone a distal pancreatectomy, and 1 who had undergone a total pancreatectomy. Tumor size, lack of jaundice at presentation, negative nodal disease, low tumor grade, and a low tumor stage were all significant predictors of survival in univariate analysis (all p < 0.05). Only tumor stage (hazard ratio [95% confidence interval]: stage IIA 1.5 [0.8 to 2.8], stage IIB 2.6 [1.4 to 4.7], stage III 1.8 [0.8 to 4.3]) and tumor grade (hazard ratio [95% confidence interval]: moderately differentiated 1.6 [0.9 to 2.9], and poorly differentiated 3.1 [1.6 to 6.2]) were independently associated with survival differences in a multivariate Cox proportional hazards model. CONCLUSIONS: We conclude that longterm survival from pancreatic adenocarcinoma is possible if the disease is identified in its early stages. These and other similar data should provide further stimulus for the development and evaluation of novel screening strategies to improve early detection of this disease.