Combined α-methylacyl coenzyme A racemase/p53 analysis to identify dysplasia in inflammatory bowel disease

Ki-67 distribution, α-methylacyl-CoA racemase (AMACR) expression and mucin phenotypes are associated with non-polypoid growth in ulcerative colitis-associated neoplasia

AIMS

Ulcerative colitis-associated neoplasia (UCAN) is characterised by multifocal tumourigenesis. A wide range of metachronous lesions have been reported to occur after endoscopic treatment of UCAN, which suggests the development of sporadic tumours in lesions treated as UCAN. Therefore, we aimed to evaluate differences of immunohistochemistry (IHC) in features and clinicopathological characteristics of intramucosal lesions in patients with ulcerative colitis (UC).

METHODS AND RESULTS

We examined 35 intramucosal lesions resected for carcinoma or dysplasia by total colectomy from patients with UC and 71 sporadic adenomas (SAs) endoscopically resected from patients without UC. UC lesions were divided into the conventional UCAN group, defined as p53 mutant pattern and normal expression of β-catenin, and the non-conventional UCAN group, defined as the rest. Ki-67 distribution, α-methylacyl-CoA racemase (AMACR) expression and mucin phenotypes were compared using IHC, and clinicopathological characteristics were investigated. Conventional and non-conventional UCAN lesions were located in the left colon and rectum. Relative to the SA lesions, UCAN lesions occurred in much younger patients and exhibited more frequent basal distribution of Ki-67 in tumour crypts. Conventional UCAN lesions tended to be non-polyploid and exhibited a higher frequency of normal AMACR expression than SA lesions. UC lesions were heterogeneous-only two of the eight patients with multiple lesions had lesions (both non-conventional UCAN lesions) exhibiting concordant IHC staining features.

CONCLUSIONS

The basal pattern of Ki-67 distribution, normal expression of AMACR and a non-intestinal mucin phenotype were determined as characteristic features suggestive of UCAN. Non-polypoid growth was another a key feature of UCAN.

MYC overexpression in inflammatory bowel disease-associated conventional dysplasia and association of subsequent low-grade dysplasia in follow-up biopsies

OBJECTIVE

Diagnosis of inflammatory bowel disease (IBD)-associated dysplastic lesions can be challenging. This study aims to evaluate MYC immunohistochemistry (IHC) as a potential biomarker for IBD-associated dysplasia and compare its effectiveness with p53 IHC.

METHODS

The study cohort included resections from 12 IBD patients with carcinoma and concurrent conventional low-grade dysplasia (LGD), as well as biopsies from 21 patients with visible conventional LGD, which were followed up for 2 years with subsequent endoscopic examination. MYC and p53 IHC and MYC-FISH analysis were performed.

RESULTS

Sensitivity for LGD detection was 67% (8/12) and 50% (6/12) for MYC and p53, respectively, but the difference was not statistically significant (p = 0.2207). MYC and p53 overexpression were not always mutually exclusive, nor were they always present simultaneously. Patients who presented dysplasia in subsequent biopsies (7/21) were found to be more likely present with multiple LGD polyps and MYC-overexpressed LGD in the initial biopsies, compared to those without subsequent dysplasia (p < 0.05). These dysplastic lesions were commonly associated with chronic colitis (p = 0.0614). The distribution of LGD sites did not show a significant difference between patients with and without subsequent LGD. In MYC overexpressed cases, homogeneously strong nuclear expression was not identified in all dysplastic epithelial cells, and no MYC amplification was found in these cases by FISH.

CONCLUSION

MYC IHC can complement p53 IHC as an adjunct biomarker for diagnosing IBD-associated conventional LGD and can be used for the prediction of subsequent LGD in the follow-up biopsies combined with endoscopic features.

Solute carrier family 12 member 2 as a proteomic and histological biomarker of dysplasia and neoplasia in ulcerative colitis

BACKGROUND AND AIMS

Ulcerative colitis (UC) patients have a greater risk of developing colorectal cancer through inflammation-dysplasia-carcinoma sequence of transformation. The histopathological diagnosis of dysplasia is therefore of critical clinical relevance, but dysplasia may be difficult to distinguish from inflammatory changes.

METHODS

A proteomic pilot study on 5 UC colorectal dysplastic patients highlighted proteins differentially distributed between paired dysplastic, inflammatory and normal tissues. The best candidate marker was selected and immunohistochemistry confirmation was performed on AOM/DSS mouse model lesions, 37 UC dysplasia, 14 UC cancers, 23 longstanding UC, 35 sporadic conventional adenomas, 57 sporadic serrated lesions and 82 sporadic colorectal cancers.

RESULTS

Differential proteomics found 11 proteins significantly more abundant in dysplasia compared to inflammation, including Solute carrier family 12 member 2 (SLC12A2) which was confidently identified with 8 specific peptides and was below the limit of quantitation in both inflammatory and normal colon. SLC12A2 immunohistochemical analysis confirmed the discrimination of preneoplastic and neoplastic lesions from inflammatory lesions in mice, UC and in sporadic contexts. A specific SLC12A2 staining pattern termed "loss of gradient" reached 89% sensitivity, 95% specificity and 92% accuracy for UC-dysplasia diagnosis together with an inter-observer agreement of 95.24% (multirater κfree of 0.90; IC95%: 0.78 - 1.00). Such discrimination could not be obtained by Ki67 staining. This specific pattern was also associated with sporadic colorectal adenomas and cancers.

CONCLUSIONS

We found a specific SLC12A2 immunohistochemical staining pattern in precancerous and cancerous colonic UC-lesions which could be helpful for diagnosing dysplasia and cancer in UC and non-UC patients.

Utility of DNA Flow Cytometric Analysis of Paraffin-embedded Tissue in the Risk Stratification and Management of 'Indefinite for dysplasia' in Patients With Inflammatory Bowel Disease

BACKGROUND AND AIMS

The clinical significance of 'indefinite for dysplasia' [IND] in patients with inflammatory bowel disease remains unclear. Currently, no biomarker can reliably differentiate reactive changes from true dysplasia and/or risk stratify IND.

METHODS

A total of 52 IND colon biopsies were analysed by DNA flow cytometry. The follow-up result of each biopsy was determined by reviewing all subsequent biopsies and endoscopic reports for the occurrence of high-grade dysplasia [HGD] or colorectal cancer [CRC] at the site of previous biopsy or in the same segment of colon.

RESULTS

The overall 1-, 3-, 5-, and 7-year detection rates of HGD or CRC in all 52 IND cases were 4.6% (95% confidence interval [CI], 0.0%-10.6%), 18.2% [95% CI, 3.5%-30.7%], 26.3% [95% CI, 8.4%-40.7%], and 31.6% [95% CI, 11.2%-47.4%], respectively. More interestingly, 10.6% of IND cases with aneuploidy were subsequently found to have HGD or CRC within 1 year [95% CI, 0.0%-23.7%], with 36.4% [95% CI, 7.1%-56.5%], 51.7% [95% CI, 16.1%-72.2%], and 59.8% [95% CI, 21.4%-79.5%] detected within 3, 5, and 7 years, respectively. By comparison, in the setting of normal DNA content, 1-, 3-, 5-, and 7-year detection rates of HGD or CRC were 0.8% [95% CI, 0.0%-2.7%], 3.3% [95% CI, 0.0%-9.6%], 5.2% [95% CI, 0.0%-14.7%], and 6.5% [95% CI, 0.0%-18.1%], respectively. Only the presence of aneuploidy was found to be a significant predictor of HGD or CRC with the estimated univariate and multivariate hazard ratios of 13.8 [p = 0.016] and 50.3 [p = 0.010], respectively.

CONCLUSIONS

IND may not be a low-risk condition for HGD or CRC. In this regard, the presence of aneuploidy can identify a subset of IND cases that are at increased risk for subsequent detection of HGD or CRC.

Expression profile of intestinal stem cell markers in colitis-associated carcinogenesis

The intestinal epithelium has two distinct two stem cell populations, namely, crypt base columnar (CBC) cells and +4 cells. Several specific markers have been identified for each stem cell population. In this study, we examined the expression profiles of these markers in colitis-associated carcinogenesis (CAC) to investigate whether they can be used as biomarkers for the early detection of dysplasia. The expression of intestinal stem cell (ISC) markers was measured by real-time polymerase chain reaction during CAC that was induced by azoxymethane and dextran sodium sulfate treatment. CBC stem cell markers increased continuously with tumor development, whereas a +4 cell expression profile was not present. CBC stem cell population was suppressed in the acute colitis and then expanded to repopulate the crypts during the regeneration period. Notably, RNA in situ hybridization revealed that all dysplasia and cancer samples showed increased expression of CBC stem cell markers in more than one-third of the tumor height, whereas regenerative glands had CBC stem cell markers confined to the lower one-third of the crypt. These results suggest that CBC stem cell markers could be a useful tool for the early detection of colitis-induced tumors.

Immunohistochemistry in the diagnosis of dysplasia in chronic inflammatory bowel disease colorectal polyps

BACKGROUND AND STUDY AIMS

Development of cancer is the most significant complication in inflammatory bowel disease (IBD). Distinguishing true dysplasia from reactive atypia in polyps is difficult, leading sometimes to the unsatisfactory diagnosis of "indefinite for dysplasia". Therefore, there is a need for the development of markers that can help improve diagnosis. We evaluated the diagnostic value of the expression of AMACR, Ki67 and p53 by immunohistochemistry in the diagnosis of dysplasia in polyps developed on IBD.

PATIENTS AND METHODS

Forty colorectal polyps in IBD were studied. These had been diagnosed over a period of 11years. Dysplasia was classified according to the Vienna Classification (version 2000). Immunohistochemistry was performed using anti-AMACR, anti-Ki67 and anti-p53 antibodies.

RESULTS

Polyps were classified as follows: 21 negative for dysplasia (ND), 10 indefinite for dysplasia (IFD), 6 low-grade dysplasia (LGD), 1 high-grade dysplasia (HGD) and 2 adenocarcinomas (ACA). AMACR positivity was observed in all polyps with HGD and ACA, 5 of the 6 LGD polyps and 3 of the 10 IFD (p=0.007). p53 immunostaining showed nuclear staining in the basal part of the crypts in 8 of the 10 IFD lesions. In ACA and HGD polyps, p53 positivity was typically observed in all epithelial cell layers (p=0.004). ACA and HGD showed diffuse and scattered staining of Ki67 along the full length of the crypts. Five lesions with LGD had extension of Ki-67 positive cells up to and into the surface epithelium. Ki67 staining in all IFD lesions was restricted to the basal third of the crypt (p<0.001). By combining the three markers, a relationship with dysplasia was statistically significant (p<0.001). Sensitivity ranged from 66.7% to 88.9% and specificity from 71.4% to 100%. The positive predictive value (PPV) for detecting dysplasia using these different antibodies ranged from 66.7% to 100% and the negative predictive value (NPV) for excluding dysplasia ranged from 85.7% to 93.3%.

CONCLUSIONS

The high degree of sensitivity and specificity of AMACR, p53 and Ki67 for dysplasia in IBD suggests that these antibodies, when combined, may be useful to detect neoplastic epithelium in this condition.

Diagnostic utility of TP53 and cytokeratin 7 immunohistochemistry in idiopathic inflammatory bowel disease-associated neoplasia

Long-standing inflammatory bowel disease is associated with increased risk of developing colorectal adenocarcinoma. Significant intra- and inter-observers' variability exists in histologic interpretation of dysplasia in surveillance biopsies. In this study, we evaluated the utility of a panel of immunohistochemical markers in diagnosing inflammatory bowel disease-associated neoplasia. We reviewed 39 colectomy specimens with inflammatory bowel disease-associated neoplasia. In these 39 cases, we identified 172 foci of interest (5 normal, 58 negative for dysplasia, 15 indefinite for dysplasia, 59 low-grade dysplasia, 18 high-grade dysplasia, and 17 invasive adenocarcinoma). They were subjected to immunohistochemistry for TP53 and CK7. Logistic regression was used to evaluate their association with the presence of dysplasia. Receiver operating characteristic curves were used to determine the optimal cutoffs and assess the diagnostic performance of TP53 and CK7. Both TP53 nuclear staining and CK7 immunoreactivity gradually increased in the progression of inflammatory bowel disease-associated neoplasia (P<0.0001). CK7 immunoreactivity increased along with the increase of inflammation severity (P=0.0002) as well as reactive changes (P=0.04) in the colonic mucosa. But TP53 nuclear staining was independent of either feature. When both TP53>8% and CK7>30% as identified from logistic regression and receiver operating characteristic curves were used to diagnose dysplasia, the specificity achieved as high as 95%. When either TP53>8% or CK7>30% was used to diagnose dysplasia, the sensitivity achieved was 82%. Our results suggested that a combination of CK7 and TP53 immunohistochemistry may be helpful in diagnosing inflammatory bowel disease-associated dysplasia in difficult cases.

European consensus on the histopathology of inflammatory bowel disease

The histologic examination of endoscopic biopsies or resection specimens remains a key step in the work-up of affected inflammatory bowel disease (IBD) patients and can be used for diagnosis and differential diagnosis, particularly in the differentiation of UC from CD and other non-IBD related colitides. The introduction of new treatment strategies in inflammatory bowel disease (IBD) interfering with the patients' immune system may result in mucosal healing, making the pathologists aware of the impact of treatment upon diagnostic features. The European Crohn's and Colitis Organisation (ECCO) and the European Society of Pathology (ESP) jointly elaborated a consensus to establish standards for histopathology diagnosis in IBD. The consensus endeavors to address: (i) procedures required for a proper diagnosis, (ii) features which can be used for the analysis of endoscopic biopsies, (iii) features which can be used for the analysis of surgical samples, (iv) criteria for diagnosis and differential diagnosis, and (v) special situations including those inherent to therapy. Questions that were addressed include: how many features should be present for a firm diagnosis? What is the role of histology in patient management, including search for dysplasia? Which features if any, can be used for assessment of disease activity? The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas.

Dysplastic lesions in inflammatory bowel disease: molecular pathogenesis to morphology

Context.-Inflammatory bowel disease (IBD) is a long-standing chronic active inflammatory process in the bowel with increased risk for the development of colorectal carcinoma. Several molecular events involved in chronic active inflammatory processes contribute to multistage progression of human cancer development, including reactive oxygen and nitrogen species, aberrant arachidonic acid metabolites and cytokines/growth factors, and immune dysfunction. These molecular events in IBD lead to genetic abnormality and promote aberrant cell proliferation, which further lead to epithelial changes encompassing a broad spectrum from inflammation-induced hyperplasia to dysplasia. Objective.-To review the (1) epidemiologic and molecular pathogenesis of the risk for colorectal cancer in IBD, (2) morphologic characterization, biomarker(s), and classification of dysplastic lesions, and (3) clinical management of dysplastic lesions arising in IBD. Data Sources.-The different IBD-related dysplastic lesions are illustrated by using morphology in conjunction with molecular pathways, and the "field cancerization" theory and its potential significance are discussed with a review of the literature. Conclusions.-Patients with IBD are at increased risk of developing colorectal cancer. The risk of developing carcinoma is related to the extent/duration/activity of the patient's disease. There is no consensus regarding the extent of carcinoma risk associated with IBD; however, all would agree that patients with IBD represent a group at significant risk for developing carcinoma and as such, warrant adequate surveillance and prevention. With better screening modalities and detection/characterization of dysplastic lesions, IBD-associated serrated lesions, and "field cancerization," we will improve our understanding of and approach to risk stratification.

Alpha-methylacyl-coenzyme A racemase expression in neuroendocrine neoplasms of the stomach

The enzyme alpha-methylacyl-coenzyme A racemase plays an important role in the beta-oxidation of branched-chain fatty acid and its derivatives. It has been used to detect prostatic adenocarcinoma and high-grade intraepithelial neoplasia, and recently also as a marker for other neoplasms, including those of the genitourinary system, breast, upper and lower gastrointestinal tract and their precursor lesions. We assessed expression of alpha-methylacyl-coenzyme A racemase by immunohistochemistry in neuroendocrine tumours of the stomach to determine differences in the incidence and pattern of expression among different types of gastric neuroendocrine tumours. While none of the grade 1 neuroendocrine tumours were immunoreactive, 67 % of grade 2 neuroendocrine tumours and 90 % of neuroendocrine carcinomas were positive for alpha-methylacyl-coenzyme A racemase. Furthermore, an adenocarcinoma component was found in 72.5 % (37 of 51) of neuroendocrine carcinomas, whereas none of the grade 1 and 2 neuroendocrine tumours contained an adenocarcinoma component. In 83 % of neuroendocrine carcinomas, the adenocarcinoma component was positive for alpha-methylacyl-coenzyme A racemase, and both adenocarcinoma and neuroendocrine carcinoma components stained positively in 78 % of these cases. Our results indicate that alpha-methylacyl-coenzyme A racemase is a useful marker for distinguishing between grade 1 (negative) and grade 2 neuroendocrine tumours, and neuroendocrine carcinoma of the stomach (frequently positive). Different patterns of alpha-methylacyl-coenzyme A racemase expression between gastric neuroendocrine tumours and neuroendocrine carcinoma suggest that these might develop via different tumourigenic pathways.

Role of immunohistochemical markers in predicting progression of dysplasia to advanced neoplasia in patients with ulcerative colitis

BACKGROUND

Although dysplasia is thought to be the precursor lesion in the development of colitis-associated colorectal cancer (CRC), a significant proportion of patients with ulcerative colitis (UC) and low-grade (LGD) or indefinite (IND) dysplasia remain cancer-free during endoscopic follow-up. There is a need for biomarkers that predict neoplastic progression. We studied the value of a series of immunohistochemical markers in UC patients with flat LGD or IND with regard to neoplastic progression.

METHODS

Tissue samples were collected from 12 UC patients (six flat LGD, six IND) without progression and from 10 UC patients (eight flat LGD, two IND) with documented progression to HGD and/or CRC during a median of 25 and 23 months of colonoscopic follow-up, respectively. Immunohistochemistry using monoclonal antibodies was performed for p53, CD44, Ki67, AMACR, β-catenin, cyclin D1, p21, and ALDH. Positive and negative staining patterns were compared for progression to advanced neoplasia.

RESULTS

When patients showed coexpression of p53 and AMACR, 6/7 patients (86%) developed advanced neoplasia, compared to 4/15 patients (27%) without p53/AMACR coexpression (P = 0.02). Patients with p53/AMACR coexpression developed advanced neoplasia in a time period of 19 months (median, range 1-101) compared to 80 months (median, range 8-169) in patients without p53/AMACR coexpression (P = 0.14). Interestingly, in three patients with progression and previous dysplasia-negative biopsies, two out of three biopsies were p53-positive a median of 12 months (range 10-14) before the LGD/IND diagnosis.

CONCLUSIONS

This study suggests a role for p53/AMACR coexpression as a potential marker of neoplastic progression in patients with UC.

Relationship between alpha-methylacyl-coenzyme A racemase expression and mucin phenotype in gastric cancer

Alpha-methylacyl-coenzyme A racemase controls β-oxidation of branched-chain fatty acid and their derivatives. Many investigators have described alpha-methylacyl-coenzyme A racemase expression in various neoplasias and their precursor lesions. Although there have been a few reports regarding alpha-methylacyl-coenzyme A racemase expression in gastric neoplasia, these reports did not discuss the relationship between alpha-methylacyl-coenzyme A racemase expression and mucin phenotype. This study analyzed alpha-methylacyl-coenzyme A racemase expression of gastric carcinomas with regard to mucin phenotype. Alpha-methylacyl-coenzyme A racemase expression was evaluated in 85 cases of gastric biopsies including gastric epithelial neoplasia and nonneoplasia and in 108 cases of surgically resected early gastric cancer. In biopsy cases, alpha-methylacyl-coenzyme A racemase was more highly expressed in neoplasia (69.7%, 23/33) than in nonneoplasia (0%, 0/42) (P = .001). Alpha-methylacyl-coenzyme A racemase was overexpressed in 20.0% (2/10) of cases that were indefinite for neoplasia, and the 2 positive cases were ultimately diagnosed as adenocarcinoma. In resected cases of early gastric adenocarcinoma, alpha-methylacyl-coenzyme A racemase expression significantly correlated with mucin phenotype (P = .003), but not with tumor progression, histologic classification, or clinicopathologic features. Alpha-methylacyl-coenzyme A racemase expression was significantly higher in intestinal-phenotype carcinoma (90.2%, 37/40) than in gastric-phenotype carcinoma (56.3%, 18/31) (P = .006) and also correlated with an increase in CDX2 expression (P = .018) and a decrease in MUC5AC expression (P = .048). This tendency was observed in all histologic types. Our results indicate that alpha-methylacyl-coenzyme A racemase is a useful marker for distinguishing gastric neoplasia from nonneoplasia even at an early stage. Alpha-methylacyl-coenzyme A racemase expression is associated with mucin phenotypes of gastric neoplasia, particularly with the expression of CDX2 and MUC5AC.

Relative role of methylator and tumor suppressor pathways in ulcerative colitis-associated colon cancer

BACKGROUND

Chronic ulcerative colitis (UC) is associated with an increased colorectal cancer risk which may be secondary to repetitive mucosal injury. Both epigenetic methylation and the classic adenoma-to-carcinoma sequence have been implicated in this malignant transformation, but the underlying molecular mechanisms remain poorly defined. This study compares the molecular characteristics of colitis-associated and common colorectal cancers.

METHODS

Nineteen patients with colorectal adenocarcinomas arising within UC were matched for age and cancer site with 54 patients with sporadic adenocarcinomas. Tumor tissue was examined for BRAF mutations, CpG island methylator phenotype (CIMP), and MLH1 promoter methylation. Mutations of KRAS and p53 were assessed by sequencing.

RESULTS

Patient demographics were similar for the two groups. CIMP was observed in 22% of sporadic colorectal cancers and in 5% of UC cancers (P = 0.162). Rates of BRAF mutation (4% vs 5%, P = 1.0), MLH1 methylation (9% versus 5%, P = 0.682), and KRAS mutations (24% versus 32%, P = 0.552) were similar between the groups. However, colitis-associated colorectal cancers were more likely to have a p53 mutation compared to sporadic adenocarcinomas (95% versus 53%, P = 0.001). The dominant mutation for colitis-associated cancers was a mutation in codon 4, representing half of the mutations. Furthermore, colitis-associated cancers had a higher rate of mutation in codon 8 (48% versus 6%, P < 0.001) than sporadic counterparts.

CONCLUSIONS

Unlike other inflammatory gastrointestinal cancers, colitis-associated colorectal cancers do not preferentially arise via a methylator pathway when compared to sporadic colorectal cancers. Chromosomal instability remains an important etiology, but with a unique p53 frequency and mutation pattern.

Colorectal dysplasia in chronic inflammatory bowel disease: pathology, clinical implications, and pathogenesis

CONTEXT

Colorectal cancer, the most lethal long-term complication of chronic inflammatory bowel disease (IBD), is the culmination of a complex sequence of molecular and histologic derangements of the intestinal epithelium that are initiated and at least partially sustained by chronic inflammation. Dysplasia, the earliest histologic manifestation of this process, plays an important role in cancer prevention by providing the first clinical alert that this sequence is underway and serving as an endpoint in colonoscopic surveillance of patients at high risk for colorectal cancer.

OBJECTIVE

To review the histology, nomenclature, clinical implications, and molecular pathogenesis of dysplasia in IBD.

DATA SOURCE

Literature review and illustrations from case material.

CONCLUSIONS

The diagnosis and grading of dysplasia in endoscopic surveillance biopsies play a decisive role in the management of patients with IBD. Although interpathologist variation, endoscopic sampling problems, and incomplete information regarding the natural history of dysplastic lesions are important limiting factors, indirect evidence that surveillance may be an effective means of reducing cancer-related mortality in the population with IBD has helped validate the histologic criteria, nomenclature, and clinical recommendations that are the basis of current practice among pathologists and clinicians. Emerging technologic advances in endoscopy may permit more effective surveillance, but ultimately the greatest promise for cancer prevention in IBD lies in expanding our thus far limited understanding of the molecular pathogenetic relationships between neoplasia and chronic inflammation.

Endoscopic and pathological aspects of colitis-associated dysplasia

The risk of developing colorectal cancer in patients with colitis-associated dysplasia is considerable. Surveillance programs in patients with ulcerative colitis and Crohn's disease aim to detect dysplastic lesions early and rely heavily on taking random biopsy samples along the length of the colon. Diagnosing dysplasia can be difficult because of the heterogeneous endoscopic appearance of dysplasia and the poor interobserver agreement among pathologists when grading dysplasia. Colitis-associated dysplasia may present as a dysplasia-associated lesion or mass (DALM), which may be indistinguishable from a sporadic adenoma in non-colitic tissue, or may arise in flat mucosa of endoscopically normal appearance. Information about the endoscopic appearance, the colonic distribution and the histopathological grade of colitis-associated dysplasia is required to define the optimal treatment. This Review summarizes the endoscopic and histopathological features of colitis-associated dysplasia and the requirements for optimal interaction between endoscopists and pathologists, with the aim of reducing the uncertainties in the diagnosis of dysplastic lesions and improving the management of colitis-associated dysplasia.