Dysplasia In Ulcerative Colitis Research Articles

A strategy combining flow sorting and comparative genomic hybridization for studying genetic aberrations at different stages of colorectal tumorigenesis in ulcerative colitis.

DNA aneuploidy has been shown to increase the risk of developing dysplasia in ulcerative colitis (UC) and is related to tumorigenesis in the colorectum. Therefore, it is of particular interest to study genetic aberrations behind DNA aneuploidization during colorectal carcinogenesis. We wanted to elucidate further the relationship between mucosal morphology and DNA aberrations in UC. DNA flow cytometry was applied to multiple lesions including regenerative, dysplastic, and carcinomatous mucosa from the colectomy specimen of a male patient with long-standing UC. The lesions harbored multiple DNA aneuploid stemlines that were subjected to flow sorting. We analyzed gene alterations by degenerate oligonucleotide primer (DOP; universal primers) polymerase chain reaction (PCR)-based comparative genomic hybridization (CGH) and fluorescent in situ hybridization (FISH) in diploid and aneuploid sorted cells. DOP-PCR-based CGH shows gains and losses that can be verified by FISH. We show that with this approach one can study genetic evolution of distinct DNA diploid and aberrant subpopulations through defined stages of colorectal tumorigenesis. This includes getting information related to tumor heterogeneity that cannot be obtained by CGH with DNA extracted from nonsorted cell populations. Genetic imbalance was also detected in diploid nondysplastic flow-sorted mucosal cells from the same bowel. Similar gains and losses were found in aneuploid dysplasias and carcinomas at widely separated locations in the same bowel, indicating a common selection pressure in different areas of the same bowel. The common aberrations may be of importance for progression from dysplasia to carcinoma.

New endoscopic techniques to identify colorectal dysplasia

Distinguishing dysplastic (adenomatous) from nondysplastic (hyperplastic) polyps is not possible using standard endoscopic techniques. Routine endoscopy is also unable to identify regions of flat dysplasia in ulcerative colitis or Barrett's esophagus. Endoscopists depend on histology to characterize these lesions, which introduces additional costs and risks and invariably delays patient management. A new series of technologies, collectively termed optical biopsy , are capable of immediate, noninvasive diagnosis of dysplasia. We shall review the 2 most promising of these technologies, namely laser-induced fluorescence (LIF) and light-scattering spectroscopy (LSS). The principle of LIF is that dysplastic cells emit light (fluoresce) differently than cells that are not dysplastic. Dysplastic cells may contain compounds capable of causing fluorescence (fluorophores), which are different from those found in nondysplastic cells or compounds which are similar but found in an abnormal concentration compared to nondysplastic cells. When a laser or filtered light is used to illuminate the intestinal mucosa, dysplastic cells give off a characteristic fluorescence that can be detected with fiber optic probes or, more recently, standard charged-coupled device (video) chips in the endoscope. Previous studies have evaluated light sources and specific wavelengths of light that optimally cause fluorescence. In addition, the fluorescence characteristics of gastrointestinal tissue are currently being assessed to determine which are best capable of distinguishing dysplastic from nondysplastic lesions. Overall, LIF is very accurate, with sensitivity and specificity of greater than 90%. However, it is less accurate in identifying low-grade, nonpolypoid dysplasia. LSS is based in part on the principle that small particles can be characterized by the way in which they scatter light. When used to study the superficial mucosa of patients with Barrett's esophagus, light-scattering spectroscopy can determine the size and number of nuclei. Because dysplastic cells develop abnormally large nuclei with a larger number of nuclei per area (crowding) than nondysplastic tissue, LSS may be able to aid in the endoscopic detection of dysplasia. Recent studies in patients with Barrett's esophagus have shown that LSS is capable of accurately detecting both low-grade and high-grade dysplasia. Importantly, because these techniques use objective parameters such as nuclear size and number, they may be less subject to the interobserver variation seen in histological interpretation of dysplasia. New techniques such as LIF and LSS have the potential to provide immediate, noninvasive tissue diagnoses that can accurately distinguish nondysplastic from dysplastic polyps and may be useful for localizing areas of nonpolypoid dysplasia in patients with ulcerative colitis or Barrett's esophagus.

Sialosyl‐Tn expression in benign and neoplastic proliferative lesions of the colon: of questionable value in predicting dysplasia

Tumour-associated carbohydrate antigen expression patterns have been observed to change during the transformation from benign to dysplastic and malignant cells. Sialosyl-Tn is an O-linked mucin-type tumour-associated antigen expressed on glycoproteins and is the product of aberrant glycosylation of the Tn glycoprotein, an early precursor of the MN blood group antigen. Sialosyl-Tn expression has been observed in adenomas and carcinomas of the colon as well as in dysplastic lesions in ulcerative colitis (UC). Sialosyl-Tn expression has been proposed to be a prognostic marker for the development of dysplasia in UC. To evaluate Sialosyl-Tn expression in benign and malignant proliferative lesions of the colon, and its relevance for prediction of dysplasia, we immunostained cases of adenoma, adenoma with invasive carcinoma, UC with and without dysplasia, hyperplastic polyps, cases of lymphocytic colitis, and cases of acute self-limited colitis with antibody against Sialosyl-Tn. We found expression of Sialosyl-Tn in dysplastic lesions in adenomas and UC. We also found expression of Sialosyl-Tn in epithelium of chronic colitis in virtually all patients with UC, both with dysplasia and without. Sialosyl-Tn was also present in hyperplastic polyps, and one single case each of lymphocytic colitis and acute self-limited colitis. We conclude that Sialosyl-Tn is expressed in dysplastic and malignant epithelial lesions of the colon. Expression of Sialosyl-Tn in benign proliferative/regenerative lesions in the colon is frequent and is not directly related to the development of dysplasia. Possible mechanisms of Sialosyl-Tn expression are discussed.

The differentiation of true adenomas from colitis-associated dysplasia in ulcerative colitis: A comparative immunohistochemical study

Adenomas in areas involved by ulcerative colitis (UCA) are difficult to identify because of their morphological similarity to ulcerative colitis-associated dysplasia (UCD) and have an uncertain biology. Recently, a set of morphopathologic criteria were published for the diagnosis of UCA versus UCD. As a first step to analyze these criteria, we studied p53 and bcl-2 expression in groups of UCA and UCD along with a sporadic adenoma control group. Ninety lesions from UC areas (62 patients) were examined, including 24 UCA without high-grade dysplasia (HGD) and 66 UCD consisting of 43 polypoid and 23 flat dysplastic lesions (29 with HGD). Immunohistochemical p53 and bcl-2 expression were evaluated semiquantitatively, P53-positive cases were significantly less frequent in the UCA (4%) versus the UCD group (30%, P = .01) and the polypoid UCD subgroup (35%, P = .005). Moderate or strong bcl-2 expression was significantly more frequent in the UCA than in the UCD group (96% v 70%, P = .01) and in the UCA versus both polypoid and flat UCD subgroups. Comparison of UCA with low-grade dysplastic polypoid UCD cases alone showed a difference just below significance for p53 ( P = .07). p53 and bcl-2 expression rates were very similar in the UCA group and the sporadic adenoma ( n = 25) control group. These results show that UCA has phenotypic features more similar to sporadic adenomas than UCD and supports the concept that adenomas in UC have a biology different from UC-associated dysplasia.

A germline h MSH2 alteration is unrelated to colonic microsatellite instability in patients with ulcerative colitis

Recently, a polymorphism in the h MSH2 DNA mismatch repair gene has been associated with the development of dysplasia in ulcerative colitis (UC) patients. This polymorphism is of interest because DNA mismatch repair defects result in alterations in microsatellite stability. The current study was designed to determine whether this h MSH2 polymorphism associates with the development of microsatellite instability and dysplasia in UC patients. The h MSH2 genotype of 96 UC patients was determined by direct DNA sequencing. In addition, we examined 363 samples of colonic mucosa from 93 of these UC patients for microsatellite mutation by polymerase chain reaction (PCR) at eight loci. Three cases had insufficient DNA for microsatellite instability studies. The h MSH2 polymorphism was identified in 13 of the 96 patients examined (13.5%). The polymorphism was observed in 7 of 46 patients with dysplasia (15.2%), and in 6 of 50 patients without dysplasia (12.0%). Microsatellite instability was identified in 35 tissue samples (25 regenerative, one indefinite for dysplasia, eight dysplasias, and one invasive carcinoma) from 26 patients. Two patients with microsatellite instability had the h MSH2 alteration. The 11 remaining patients had the h MSH2 polymorphism, but no evidence of microsatellite mutations with any of the markers tested. We were unable to confirm the previously reported findings that the specific germline h MSH2 alteration represents a marker for increased risk of dysplasia in patients with UC, nor is it responsible for the development of microsatellite instability in these patients.

Ki-67: a useful marker for the evaluation of dysplasia in ulcerative colitis.

AIMS: Evaluation of dysplasia in long standing ulcerative colitis is a difficult and often subjective task. Therefore, the aim of this study was to search for a more objective parameter...

Loss of heterozygosity of the von hippel lindau gene locus in polypoid dysplasia but not flat dysplasia in ulcerative colitis or sporadic adenomas

Carcinoma in ulcerative colitis (UC) develops from dysplastic precursor lesions, which include flat dysplasia (FD) and polypoid dysplasias (PD). PD may present as single or multiple polypoid structures or as plaque-like lesions that, independent of histological grade, are an indication for colectomy. PDs are histologically similar to adenomas and may not be readily distinguished by light microscopy. It is not known whether FD and PD are different entities, or whether they represent etiologically similar lesions with different morphological expression. We microdissected 25 cases of UC with PD and 19 samples of FD with surrounding chronic colitis (CC) in UC. Loss of heterozygosity (LOH) at the von Hippel Lindau (vHL) gene locus and the putative tumor suppressor genes APC, INK4A (9pl6), and p53 was studied. LOH of the vHL gene, INK4A (9pl6), and APC was also studied in 11 sporadic adenomas of the colon. LOH at the vHL locus was present in 50% of the samples of PD and in 12% of the samples of FD. LOH was seen in CC close to PD and FD in 26% and 12% of cases, respectively. No adenoma showed LOH of the vHL gene markers studied. LOH in p53 was seen in PD in 16% cases and in FD in 42% cases and in CC close to PD and FD in 0% and 14% cases, respectively. LOH patterns between PD and FD of the markers for APC and 9p16 were not different. LOH in APC was seen in two of five cases of adenoma. We conclude that PD and FD share genetic alterations in APC and 9p16 genes. More frequent involvement of the VHL gene in PD and surrounding CC and involvement of p53 in HGD and CC in FD may represent genetic differences between the development of PD and FD and may be the cause of the different morphology. The infrequency of LOH at the vHL locus in adenomas versus PD may serve as a discriminator between adenomas and PD in diagnostically problematic cases.

Management of dysplasia in ulcerative colitis: is prophylactic colectomy the preferred strategy?

Surveillance followed by colectomy is of limited benefit. A policy of colectomy at 10 years or more, surprisingly, may not prevent all cancers. The quality of life after restorative proctocolectomy is acceptable. Workload and cost benefit are difficult to predict inasmuch as little work has been done in those areas. Rigorous medical treatment with close followup and early colectomy in those in whom this seems clinically appropriate may be the best approach to this condition. Ulcerative colitis is a variable condition and patients themselves differ in terms of their hopes, aspirations, and expectations. An individual and flexible approach therefore is probably more desirable than a rigid protocol.

Risk factors for cancer or dysplasia in ulcerative colitis with primary sclerosing cholangitis

Risk factors for cancer or dysplasia in ulcerative colitis with primary sclerosing cholangitis

Comparison of genetic alterations in colonic adenoma and ulcerative colitis-associated dysplasia and carcinoma

Carcinoma is an important complication of ulcerative colitis (UC) and develops from dysplastic precursor lesions. Genetic changes involved in the malignant transformation have not been fully characterized. We studied 19 cases of UC with high-grade dysplasia (HGD) and eight samples of associated carcinoma (CA). Microdissection of normal epithelium, epithelium at the site of chronic inflammation, HGD, and CA was performed. Polymerase chain reaction (PCR) amplification for loss of heterozygosity (LOH) of the following polymorphic microsatellites of putative tumor suppressor gene loci was done: APC (5q), DCC (l8q), p16 (9p), p53 (17p), and 8p12. To compare genetic alterations, 22 typical adenomas of the colon were studied with the markers for APC and p16 gene loci. p ]The results indicated that LOH of p16 and p53 were present in nondysplastic epithelium, HGD, and CA. However, the LOH in nondysplastic epithelium was detected in some associated HGD, but not all. Whereas LOH of p16 was present in 7 of 14 cases of HGD (50%), it was noted in only 1 of 22 adenomas (5.0%). LOH in the APC and DCC gene loci in UC was noted in HGD with associated CA, but LOH of APC was not present either in cases of nondysplastic epithelium or in HGD alone. Conversely, LOH in APC was present in 4 of 19 colonic adenomas. We conclude that LOH of p53 and p16 in nondysplastic epithelium may be associated with chronic reparative processes. These changes may lead to susceptibility to further genetic damage involving the APC and DCC gene loci in the development of dysplasia and progression of CA in UC. The low frequency of LOH in the p16 gene (9p) in adenomas compared with dysplasia in UC combined with infrequent LOH in APC gene loci in cases of pure dysplasia in UC may support this combination of markers as a clinical test for the differentiation of polypoid dysplasia from adenomas in UC.

The DNA content of chromosome division figures and interphase nuclei classifies ulcerative colitis

Long-standing ulcerative colitis is considered to be a precancerous condition. Therefore, a practical and reliable method is required for monitoring the progress of the disease. Liberation of the S-phase from karyokinesis occurs in DNA amplification and endoreplication, producing nuclei with more than 4 c DNA. The amount of Feulgen DNA was quantified with an image microphotometer in 8μm sections for interphase nuclei and in 15μm sections for chromosome division figures (CDFs). Development of ulcerative colitis was investigated in low grade dysplasia (n=93 cases; score 3–7) and high grade dysplasia (n=22; score 8–10). Bacterial colitis (n=34) and invasive adenocarcinoma (n=26) provided a basis for data interpretation in dysplasia. Lymphocyte nuclei served as an internal DNA standard. CDFs represent a novel type of aberrant ‘mitoses’; they are different from and much more frequent than figures with multipolar spindles. Endoreplication began with low grade dysplasia in interphase nuclei as well as with CDFs; it was fully established in high grade dysplasia and carcinoma. Endoreplicated interphase nuclei and CDFs represent an early morphological mosaic of genomic instability. Both characteristics support a reproducible two-level classification of low and high grade dysplasia in ulcerative colitis.

The pathology and politics of dysplasia in ulcerative colitis

The pathology and politics of dysplasia in ulcerative colitis

Comparison of Nuclear Matrix Protein Composition in Colon Cancer and Dysplasia

Background: Abnormal nuclear morphology associated with cancer may reflect changes in the proteins of the nuclear matrix. Methods: Nuclear matrix (NM) proteins were isolated from colonic tissue and analyzed by two-dimensional gel electrophoresis. Results: Several matrix proteins that were found in ulcerative colitis (UC) dysplasia (n = 5) and/or UC cancer (n = 4) were not identified in normal colonic tissue. UC dysplasia tissue showed three specific NM proteins with molecular masses of 49.2 kDa, 20.0 kDa, and 19.0 kDa, whereas 29.0-kDa and 32.0-kDa proteins were specific to UC cancer. Three proteins with 59.5-kDa (pI 6.3 and 6.6) and 33.75-kDa (pI 7.5) masses were common to both dysplasia and cancer tissue. Conclusions: These data suggest that NM proteins may have a role in the transition of tissue towards the malignant phenotype.

Chromosomal alterations in ulcerative colitis-related neoplastic progression

BACKGROUND & AIMS: It is unclear whether genomic derangement precedes the histological development of dysplasia in ulcerative colitis (UC)- related neoplastic progression. The primary aim of this study was to determine if chromosomal alterations occur early in the progression pathway of UC-related neoplasia. METHODS: Fluorescence in situ hybridization (FISH) was performed on nuclei dissociated from sites of cancer, dysplasia, and UC-involved nondysplastic epithelium in five UC- related cancer colectomy specimens using a panel of pericentromeric probes. Comparative genomic hybridization (CGH) was used to detect clonal chromosomal losses and gains in DNA extracted from these sites. RESULTS: FISH analysis revealed significant and often dramatic alterations in chromosome copy number compared with controls in all biopsy specimens of cancer, dysplasia, and nondysplastic UC-involved epithelium. Clonal chromosomal losses and gains were detected by CGH in all but one analyzed site of dysplasia and cancer and in two of the five nondysplastic sites. FISH and CGH frequently detected the relative loss of chromosome 18. CONCLUSIONS: Chromosomal alterations may occur early in UC-related neoplastic progression and seem to precede the histological development of dysplasia. Relative loss of 18q may be important in the progression of UC-related neoplasia. The detection of chromosomal alterations as an intermediate end point may prove useful in identifying patients at high risk for the development of colorectal cancer. (Gastroenterology 1997 Sep;113(3):791-801)

The effect of folic acid supplementation on the risk for cancer or dysplasia in ulcerative colitis

BACKGROUND & AIMS: Two case-control studies have shown that folate may protect against neoplasia in ulcerative colitis. This historical cohort study was performed to better define this association. METHODS: The records of 98 patients with ulcerative colitis who had disease proximal to the splenic flexure for at least 8 years were reviewed. Documented folate use of at least 6 months was deemed a positive exposure. RESULTS: Of the patients, 29.6% developed neoplasia and 40.2% took folate supplements. The adjusted relative risk (RR) of neoplasia for patients taking folate was 0.72 (95% confidence interval [CI], 0.28- 1.83). The dose of folate varied with the risk of neoplasia (RR, 0.54 for 1.0 mg folate; RR, 0.76 for 0.4 mg folate in a multivitamin compared with patients taking no folate). Folate use also varied with the degree of dysplasia (RR for cancer, 0.45; RR for high-grade dysplasia, 0.52; RR for low-grade dysplasia, 0.75 compared with patients with no dysplasia) (P = 0.08). CONCLUSIONS: Although not statistically significant, the RR for folate supplementation on the risk of neoplasia is > 1 and shows a dose-response effect, consistent with previous studies. Daily folate supplementation may protect against the development of neoplasia in ulcerative colitis. (Gastroenterology 1997 Jan;112(1):29-32)

Inflammatory Fibroid Polyp in a Continent Ileo-anal Pouch after Colectomy for Ulcerative Colitis — Case Report

The most frequent complication occurring in continent ileo-anal pouches after colectomy for ulcerative colitis (UC) is pouchitis. Recurrences of adenomas or carcinomas in pouches of familial adenomatous polyposis (FAP) patients are exceptional, whereas in those with ulcerative colitis dysplasia it is a very rare occurrence. We describe the case of a young woman who developed a mass in a J pouch three years after its construction following colectomy for ulcerative colitis. Histological and immunohistochemical studies showed that this mass had the features of an inflammatory fibroid polyp. A review of the literature of lesions observed in continent ileo-anal pouches after colectomy for UC would suggest that this lesion is an exceedingly rare complication of those devices.

The demonstration of pericryptal fibroblasts in background mucosa and dysplasia complicating ulcerative colitis.

The demonstration of pericryptal fibroblasts in background mucosa and dysplasia in ulcerative colitis was investigated by immunohistochemistry using monoclonal antibody for alpha-smooth muscle actin. Pericryptal fibroblasts were reduced in 18 (26%) of the 68 sections of non-dysplastic mucosa. The reduction was significantly correlated with goblet cell depletion and villous change. Pericryptal fibroblasts were more frequently reduced (50%) in dysplastic mucosa, the reduction being greater in villous than in non-villous dysplasia. Pericryptal fibroblast development was not related to grade of dysplasia (low or high-grade), distance from carcinoma (adjacent to or distant from carcinoma) or growth pattern (polypoid or non-polypoid). These findings suggest that: 1 reduction of pericryptal fibroblasts in background mucosa may relate to the development of dysplasia in ulcerative colitis, 2 reduction of pericryptal fibroblasts in villous regeneration, analogous to that in dysplasia, reinforces the hypothesis that villous change may be a marker for risk of development of carcinoma in ulcerative colitis.

Sialosyl-Tn antigen is prevalent and precedes dysplasia in ulcerative colitis: A retrospective case-control study

BACKGROUND & AIMS: Expression of the carbohydrate-associated sialosyl- Tn (STn) antigen has been correlated with carcinogenesis in sporadic colon cancer. This retrospective study analyzed surveillance colonoscopy biopsy specimens to determine whether STn antigen could serve as a marker for neoplasia risk in patients with long-standing ulcerative colitis. METHODS: Eleven patients who developed dysplasia or cancer and who had undergone at least three surveillance colonoscopies were matched with 11 controls who had not developed neoplasia. Sections from 969 available surveillance biopsy specimens were stained immunohistochemically with monoclonal antibody TKH2 and were interpreted blindly. RESULTS: Compared with controls, patients expressed STn antigen more frequently in their biopsy specimens (44% patient biopsy specimens vs. 11% control biopsy specimens). Patients were also more likely to undergo colonoscopies with two or more colonic segments expressing STn antigen (73% vs. 22%), repeated STn antigen expression in two or more consecutive colonoscopies (91% vs. 27%), and STn antigen expression proximal to the hepatic flexure (64% vs. 0%). STn antigen appearance preceded the detection of neoplasia by 7 or fewer years, and its preferential expression in patients was not confounded by the degree of active inflammation. CONCLUSIONS: Repeated STn antigen expression in nondysplastic colonic mucosa may presage the development of neoplasia in long-standing ulcerative colitis and may be a useful adjunct to dysplasia during colonoscopic surveillance. (Gastroenterology 1996 Mar;110(3):694-704)

Molecular genetics of dysplasia in ulcerative colitis.

Numerous molecular genetic events occurring in the development of sporadic colorectal neoplasia have been previously defined. The most frequent genetic alterations are mutations of the APC, KRAS, and TP53 genes, as well as loss of the DCC gene and of the second TP53 allele. The data from several groups indicate that these genes play an important role in ulcerative colitis-associated dysplasias and cancer, as they do in sporadic colorectal adenomas and carcinomas. KRAS and TP53 mutations were detected in dysplasia, but also in villous regeneration and active colitis, and affect a subpopulation of the cells composing these lesions. We conclude that in histologically defined dysplasia, clones can be found that genetically represent precancerous lesions in ulcerative colitis. Seen in this way, part of the active colitis and villous regeneration lesions might be considered as preneoplastic. When present, KRAS mutation is an excellent genetic marker to map populations of preneoplastic cells.

Endoscopic appearance of dysplasia in ulcerative colitis

Endoscopic appearance of dysplasia in ulcerative colitis