Hyperplastic polyps of the colorectum - Innocent or guilty?

Hyperplastic polyps have traditionally been regarded as nonneoplastic polyps lacking malignant potential. The demonstration of genetic alterations within these lesions indicates an underlying neoplastic cause. There is evidence that hyperplastic polyps are heterogeneous. Most are innocuous, but subsets may have malignant potential. Risk factors for neoplastic progression include multiple, large, and proximally located polyps. Aberrant methylation resulting in the silencing of cancer genes may be an important underlying mechanism, particularly in pathways progressing to tumors with DNA microsatellite instability. Lesions intermediate between hyperplastic polyp and cancer include admired polyps and serrated adenomas. Currently, pathologists have different thresholds for diagnosing serrated adenomas, including the distinction from large hyperplastic polyps. Reasons for over looking this pathway in the past may include rapid tumor progression and the fact that proximally located hyperplastic polyps may be flat and not especially numerous. Management of the serrated pathway of colorectal neoplasia may require novel approaches to screening, early detection, and prevention.

Serrated adenoma of the colorectum

An understanding of the pathology and natural history of serrated adenoma of the colorectum has emerged slowly and comparatively recently. In this review, hyperplastic polyps, admixed polyps and serrated adenomas are conceived as a continuum of serrated polyps. Mechanisms underlying the expression of serrated morphology are outlined. The demographic, macroscopic and microscopic features of serrated adenoma are presented but it is stressed that the distinction from other epithelial polyps may not always be straightforward. Molecular studies point to heterogeneity within the serrated pathway and among conditions encompassed by the term serrated polyposis. Management of serrated adenoma is discussed but the need for further research is emphasized. The importance of serrated adenoma as a precancerous lesion has been underestimated. © 2002 Elsevier Science Ltd.

The volume effect in irradiated mouse colorectum

Damage of the colorectum is the dose-limiting normal tissue complication following radiotherapy of prostate and cervical cancers. One approach for decreasing complications is to physically reduce the treatment volume. Mathematical models have been previously developed to describe the change in associated toxicity with a change in irradiated volume, i.e. the "volume effect", for serial-type normal tissues including the colorectum. The first goal of this thesis was to test the hypothesis that there would not be a threshold length in the development of obstruction after irradiation of mouse colorectum, as predicted by the Probability model of the volume effect. The second goal was to examine if there were differences in the threshold and in the incidence of colorectal obstruction after irradiation of two mouse strains, C57B1/6 (C57) and C3Hf/Kam (C3H), previously found to be fibrosis-prone and-resistant, respectively, after lung irradiation due, in part, to genetic differences. The hypothesis examined was that differences in incidence between strains were due to the differential expression of the fibrogenic cytokines $\rm TGF\beta$ and $\rm TNF\alpha.$ Various lengths of C57 and C3H mouse colorectum were irradiated and the incidence of colorectal obstruction was followed up to 15 months. A threshold length was observed for both mouse strains, in contradiction of model predictions. The mechanism of the threshold was epithelial regeneration after irradiation. C57 mice had significantly higher incidence of colorectal obstruction compared to C3H mice, especially at smaller irradiated lengths. Colorectal tissue was obtained at various times after irradiation and prepared for histology, immunohistochemistry and RNase protection assay for measurement of $\rm TGF\beta 1,$ 2, 3 and $\rm TNF\alpha$ mRNA. Distinct strain differences in the histological time of appearance and spatial locations of fibrosis were observed. However, there were no consistent strain difference in mRNA levels or immunolocalization for any of the cytokines examined. The data indicate the need for volume effect models that account for biologically important processes, such as the effect of epithelial regeneration after irradiation. As well, changes in fibrogenic cytokines at the mRNA level do not contribute to the strain difference in radiation-induced colorectal obstruction. ^

Deprivation and emergency admissions for cancers of colorectum, lung, and breast in south east England: ecological study

Objectives: To examine the relation between deprivation and acute emergency admissions for cancers of the colon, rectum, lung, and breast in south east England.

Neoplastic progression occurs through mutator pathways in hyperplastic polyposis of the colorectum

Aim-Colorectal cancer has been described in association with hyperplastic polyposis but the mechanism underlying this observation is unknown. The aim of this study was to characterise foci of dysplasia developing in the polyps of subjects with hyperplastic polyposis on the basis of DNA microsatellite status and expression of the DNA mismatch repair proteins hMLH1, hMSH2, and hMSH6. Materials and methods-The material was derived from four patients with hyperplastic polyposis and between one and six synchronous colorectal cancers. Normal (four), hyperplastic (13), dysplastic (13), and malignant (11) samples were microdissected and a PCR based approach was used to identify mutations at 10 microsatellite loci, TGF beta IIR, IGF2R, BAX, MSH3, and MSH6. Microsatellite instability-high (MSI-H) was diagnosed when 40% or more of the microsatellite loci showed mutational bandshifts. Serial sections were stained for hMLH1, hMSH2, and hMSH6. Result-DNA microsatellite instability was found in 1/13 (8%) hyperplastic samples, in 7/13 (54%) dysplastic foci, and in 8/11 (73%) cancers. None of the MSI-low (MSI-L) samples (one hyperplastic, three dysplastic, two cancers) showed loss of hMLH1 expression. All four MSI-H dysplastic foci and six MSI-H cancers showed loss of hMLH1 expression. Loss of hMLH1 in MSI-H but not in MSI-L lesions showing dysplasia or cancer was significant (p< 0.001, Fisher's exact test). Loss of hMSH6 occurred in one MSI-H cancer and one MSS focus of dysplasia which also showed loss of hMLH1 staining. Conclusion-Neoplastic changes in hyperplastic polyposis may occur within a hyperplastic polyp. Neoplasia may be driven by DNA instability that is present to a low (MSI-L) or high (MSI-H) degree. MSI-H but not MSI-L dysplastic foci are associated with loss of hMLH1 expression. At least two mutator pathways drive neoplasia in hyperplastic polyposis. The role of the hyperplastic polyp in the histogenesis of sporadic DNA microsatellite unstable colorectal cancer should be examined.

Serrated route to colorectal cancer: back street or super highway?

Morphological and molecular studies are beginning to distinguish separate evolutionary pathways for colorectal cancer, The serrated pathway encompassing hyperplastic aberrant crypt foci, hyperplastic polyps. mixed polyps, and serrated adenoma is increasingly being linked with genetic alterations, including DNA methylation, DNA microsatellite instability, Ii-ras mutation, and loss of chromosome Ip, The importance of the serrated pathway has been underestimated in terms of its frequency and potential for rapid progression, Copyright (C) 2001 John Wiley & Sons, Ltd.

Molecular and cellular biology of pre-malignancy in the gastrointestinal tract

Important pathogenic alterations within established cancers are acquired during the premalignant stage. These genetic alterations can be grouped into specific neoplastic pathways that differ within and between anatomical sites. By understanding the mechanisms that determine the initiation and progression of each pathway, it will be possible to develop novel approaches to the diagnosis, prevention and treatment of cancer. This chapter outlines the principles underlying the molecular characterization of pre-malignant lesions, taking colorectal neoplasia as the main model.

Cruciferous vegetables and cancer risk in a network of case-control studies.

Background Cruciferous vegetables have been suggested to protect against various cancers, though the issue is open to discussion. To further understand their role, we analyzed data from a network of case-control studies conducted in Italy and Switzerland. Patients and methods The studies included a total of 1468 cancers of the oral cavity/pharynx, 505 of the esophagus, 230 of the stomach, 2390 of the colorectum, 185 of the liver, 326 of the pancreas, 852 of the larynx, 3034 of the breast, 367 of the endometrium, 1031 of the ovary, 1294 of the prostate, 767 of the kidney, and 11 492 controls. All cancers were incident, histologically confirmed; controls were subjects admitted to the same network of hospitals as cases for a wide spectrum of acute nonneoplastic conditions. Results The multivariate odds ratio (OR) for consumption of cruciferous vegetables at least once a week as compared with no/occasional consumption was significantly reduced for cancer of the oral cavity/pharynx (OR = 0.83), esophagus (OR = 0.72), colorectum (OR = 0.83), breast (OR = 0.83), and kidney (OR = 0.68). The OR was below unity, but not significant, for stomach (OR = 0.90), liver (OR = 0.72), pancreatic (OR = 0.90), laryngeal (OR = 0.84), endometrial (OR = 0.93), ovarian (OR = 0.91), and prostate (OR = 0.87) cancer. Conclusion This large series of studies provides additional evidence of a favorable effect of cruciferous vegetables on several common cancers.

Trends in mortality from major cancers in the americas : 1980-2010

BACKGROUND: Between the 1970's and 2000 mortality in Latin America showed favorable trends for some common cancer sites, including stomach and male lung cancer in most countries. However, major concerns were related to mortality patterns from other cancers, particularly in women. We provide an up-to-date picture of patterns and trends in cancer mortality in Latin America. METHODS: We analyzed data from the World Health Organization mortality database in 2005-2009 for 20 cancer sites in 11 Latin American countries and, for comparative purposes, in the USA and Canada. We computed age-standardized (world) rates (per 100 000 person-year) and provided an overview of trends since 1980 using joinpoint regression models. RESULTS: Cancer mortality from some common cancers (including colorectum and lung) is still comparatively low in Latin America, and decreasing trends continue for some cancer sites (including stomach, uterus, male lung cancers) in several countries. However, there were upward trends for colorectal cancer for both sexes, and for women lung and breast cancer mortality in most countries. During the last decade, lung cancer mortality in women rose by 1-3% per year in all Latin American countries except Mexico and Costa Rica, whereas rises of about 1% were registered for breast cancer in Brazil, Colombia and Venezuela. Moreover, high mortality from cancer of the cervix uteri was recorded in most countries, with rates over 13/100 000 women in Cuba and Venezuela. In men, upward trends were registered in prostate cancer mortality in Brazil and Colombia, but also in Cuba, where the rate in 2005-2009 was more than twice that in the USA (23.6 versus 10/100 000). CONCLUSIONS: Tobacco control, efficient screening programs, early cancer detection and widespread access to treatments continue to be a major priority for most Latin American countries.

European cancer mortality predictions for the year 2014.

BACKGROUND: From most recent available data, we projected cancer mortality statistics for 2014, for the European Union (EU) and its six more populous countries. Specific attention was given to pancreatic cancer, the only major neoplasm showing unfavorable trends in both sexes. PATIENTS AND METHODS: Population and death certification data from stomach, colorectum, pancreas, lung, breast, uterus, prostate, leukemias and total cancers were obtained from the World Health Organisation database and Eurostat. Figures were derived for the EU, France, Germany, Italy, Poland, Spain and the UK. Projected 2014 numbers of deaths by age group were obtained by linear regression on estimated numbers of deaths over the most recent time period identified by a joinpoint regression model. RESULTS: In the EU in 2014, 1,323,600 deaths from cancer are predicted (742,500 men and 581,100 women), corresponding to standardized death rates of 138.1/100,000 men and 84.7/100,000 women, falling by 7% and 5%, respectively, since 2009. In men, predicted rates for the three major cancers (lung, colorectum and prostate cancer) are lower than in 2009, falling by 8%, 4% and 10%, respectively. In women, breast and colorectal cancers had favorable trends (-9% and -7%), but female lung cancer rates are predicted to rise 8%. Pancreatic cancer is the only neoplasm with a negative outlook in both sexes. Only in the young (25-49 years), EU trends become more favorable in men, while women keep registering slight predicted rises. CONCLUSIONS: Cancer mortality predictions for 2014 confirm the overall favorable cancer mortality trend in the EU, translating to an overall 26% fall in men since its peak in 1988, and 20% in women, and the avoidance of over 250,000 deaths in 2014 compared with the peak rate. Notable exceptions are female lung cancer and pancreatic cancer in both sexes.

Recent advances in intestinal lymphomas.

A large variety of lymphoma types may develop as primary intestinal neoplasms in the small intestines or, less often, in the colorectum. Among these are a few entities such as enteropathy-associated T-cell lymphoma or immunoproliferative small intestinal disease that, essentially, do not arise elsewhere than in the gastrointestinal tract. In most instances the primary intestinal lymphomas belong to entities that also occur in lymph nodes or other mucosal sites, and may show some peculiar features. In the case of follicular lymphoma, important differences exist between the classical nodal cases and the intestinal cases, considered as a variant of the disease. It is likely that the local intestinal mucosal microenvironment is a determinant in influencing the pathobiological features of the disease. In this review we will present an update on the clinical, pathological and molecular features of the lymphoid neoplasms that most commonly involve the intestines, incorporating recent developments with respect to their pathobiology and classification. We will emphasize and discuss the major differential diagnostic problems encountered in practice, including the benign reactive or atypical lymphoid hyperplasias, indolent lymphoproliferative disorders of T or natural killer (NK) cells, and Epstein-Barr virus (EBV)-related lymphoproliferations.

European cancer mortality predictions for the year 2011.

Background: Mortality figures become available after some years.Materials and methods: Using the World Health Organization mortality and population data, we estimated numbers of deaths in 2011 from all cancers and selected sites for the European Union (EU) and six major countries, by fitting a joinpoint model to 5-year age-specific numbers of deaths. Age-standardized rates were computed using EUROSTAT population estimates.Results: The predicted number of cancer deaths in the EU in 2011 was 1 281 436, with standardized rates of 143/100 000 men and 85/100 000 women. Poland had the highest rates, with smaller falls over recent periods. Declines in mortality for major sites including stomach, colorectum, breast, uterus, prostate and leukemias, plus male lung cancer, will continue until 2011, and a trend reversal or a leveling off is predicted where upward trends were previously observed. Female lung cancer rates are increasing in all major EU countries except the UK, where it is the first cause of cancer death, as now in Poland. The increasing pancreatic cancer trends in women observed up to 2004 have likely leveled off.Conclusions: Despite falls in rates, absolute numbers of cancer deaths are stable in Europe. The gap between Western and former nonmarket economy countries will likely persist.

Evidence for classification of c.1852_1853AA>GC in MLH1 as a neutral variant for Lynch syndrome

Background: Lynch syndrome (LS) is an autosomal dominant inherited cancer syndrome characterized by early onset cancers of the colorectum, endometrium and other tumours. A significant proportion of DNA variants in LS patients are unclassified. Reports on the pathogenicity of the c.1852_1853AA>GC (p.Lys618Ala) variant of the MLH1 gene are conflicting. In this study, we provide new evidence indicating that this variant has no significant implications for LS.Methods: The following approach was used to assess the clinical significance of the p.Lys618Ala variant: frequency in a control population, case-control comparison, co-occurrence of the p.Lys618Ala variant with a pathogenic mutation, co-segregation with the disease and microsatellite instability in tumours from carriers of the variant. We genotyped p.Lys618Ala in 1034 individuals (373 sporadic colorectal cancer [CRC] patients, 250 index subjects from families suspected of having LS [revised Bethesda guidelines] and 411 controls). Three well-characterized LS families that fulfilled the Amsterdam II Criteria and consisted of members with the p.Lys618Ala variant were included to assess co-occurrence and co-segregation. A subset of colorectal tumour DNA samples from 17 patients carrying the p.Lys618Ala variant was screened for microsatellite instability using five mononucleotide markers.Results: Twenty-seven individuals were heterozygous for the p.Lys618Ala variant; nine had sporadic CRC (2.41%), seven were suspected of having hereditary CRC (2.8%) and 11 were controls (2.68%). There were no significant associations in the case-control and case-case studies. The p.Lys618Ala variant was co-existent with pathogenic mutations in two unrelated LS families. In one family, the allele distribution of the pathogenic and unclassified variant was in trans, in the other family the pathogenic variant was detected in the MSH6 gene and only the deleterious variant co-segregated with the disease in both families. Only two positive cases of microsatellite instability (2/17, 11.8%) were detected in tumours from p.Lys618Ala carriers, indicating that this variant does not play a role in functional inactivation of MLH1 in CRC patients.Conclusions: The p.Lys618Ala variant should be considered a neutral variant for LS. These findings have implications for the clinical management of CRC probands and their relatives.

Second primary cancers in the Vaud and Neuchâtel Cancer Registries

An increasing proportion of new cancers is registered in patients who have received a previous cancer diagnosis. As data are inconsistent across studies, we provided information for populations long covered by valid cancer registration. Data were derived from the Swiss cancer Registries of Vaud and Neuchâtel (885 000 inhabitants). Patients diagnosed with a new malignancy (except skin basal and squamous cell carcinomas) during the period 2005-2010 were included. Over the period 2005-2010, 24 859 patients were registered with incident cancer. Of these, 3127 (13%) had multiple primary cancers and 578 (2.3%) were synchronous. Breast, prostate, colorectum, skin, melanomas, and squamous cell carcinomas of the head and neck (SHN) and bladder/ureter were the most common sites of first neoplasms, whereas breast, lung, colorectum, prostate, melanoma, and SHN were the most common sites of second neoplasms. The most common pairing was breast with breast (31% synchronous), followed by the bladder/ureter with the prostate (72% synchronous), prostate with the colorectum, SHN with SHN, and SHN with lung. Five-year crude survival of patients with synchronous cancers (34%) was not significantly lower than that of patients with single neoplasms (39%).