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

Hyper Mucinous Proliferations in the Mucosa of Patients with Inflammatory Bowel Disease: Histological Lesions with a Real Potential for Neoplastic Evolution?

BACKGROUND AND AIMS

Mucin disfunction is a critical event in the pathogenesis of inflammatory bowel disease (IBD). Although hyper mucinous conditions have a still debated implication in the clinical evolution of this disorder, hyper mucinous villous proliferations were found to have a preneoplastic biologic potential. We studied morphologic and immunophenotypic characteristics of these lesions in ileocolonic resections for IBD to add evidence about the evolutive potential of these lesions in samples with well oriented wall structures.

METHODS

Morphologic characteristics of bowel samples from 20 patients resected for IBD and with raised lesions at gross examination were studied and sections from cases with hyper mucinous lesions were stained with the following antibodies: Ki 67, p21, and p27, which were employed to evaluate the characteristics of the proliferative and differentiative activity of the epithelial structures; mismatch repair proteins and p53 have been studied as proteins implicated in carcinogenesis in IBD-affected mucosa; mucins subtypes in hyper mucinous structures were evaluated with MUC-2 and MUC-6. The results in 11 cases of saplings were that they harbored hyper mucinous proliferations. The occurrence of hyper mucinous structures was not related to dysplastic lesions, pseudo pyloric metaplasia, subtype of disease, or activity. In only one of our cases, mild cytologic atypia in the proliferative compartment was detected. Proliferation markers (Ki 67, p53) were expressed in the proliferative compartments of mucosal crypts and antiproliferative proteins p21 and p27 were expressed in differentiated epithelium. MMR proteins expression was limited to the proliferative compartment of the hyper mucinous projections. Mucin subtypes distribution was regular in the epithelium of hyper mucinous proliferations.

CONCLUSIONS

The present monocentric retrospective study was conducted on surgical samplings with well oriented crypts. Collected data show that hyper mucinous features are frequent occurrences in raised lesions in IBD patients. In hyper mucinous proliferations of the selected cases, the status of the proliferative cycle, the expression of the proteins most frequently involved in carcinogenetic pathways of mucosa affected by IBD, and the mucins subtypes expression have no evident anomalies. Findings are not consistent with the increased risk of neoplastic evolution observed in other studies; rather, they suggest a hyperplastic nature. However, the capacity of hyper mucinous raised lesions for neoplastic evolution should be ruled out with more extensive prospective studies to identify functional defects that could explain the hypothesized neoplastic potential.

Association Between Loss of SATB2 Expression in Inflammatory Bowel Disease Indefinite for Dysplasia and a Diagnosis of Definitive Dysplasia on Follow-up

Special AT-rich sequence-binding protein 2 (SATB2) is a sensitive and specific biomarker for sporadic colonic adenocarcinomas. Previous studies have found that SATB2 is lost in some adenocarcinomas and dysplasias associated with inflammatory bowel disease (IBD). In establishing these findings, the prior studies did not examine cases of IBD interpreted as indefinite for dysplasia. We examined SATB2 expression in this diagnostic category to determine if any potential loss is associated with a diagnosis of definitive dysplasia on follow-up. To investigate this possibility, we collected 87 biopsies of IBD indefinite for dysplasia from 62 patients and stained them with SATB2. Among patients' indefinite for dysplasia, we found SATB2 loss in 6/62 (9.7%). Among those with follow-up (n=51), we observed 5/6 (83%) with a future dysplasia in those with SATB2 loss compared with 10/45 (22%) in those with SATB2 retention, absolute difference 61.1% (95% confidence interval=28.9%-93.3%). We conclude that loss of SATB2 on biopsies otherwise interpreted as IBD indefinite for dysplasia may mark a population at high risk for showing definitive dysplasia on future biopsies.

Immunoexpression of oral brush biopsy enhances the accuracy of diagnosis for oral lichen planus and lichenoid lesions

Background

This study assessed the efficacy of using oral liquid‐based brush cytology (OLBC) coupled with immunostained cytology‐derived cell‐blocks, quantified using machine‐learning, in the diagnosis of oral lichen planus (OLP).

Methods

Eighty‐two patients diagnosed clinically with either OLP or oral lichenoid lesion (OLL) were included. OLBC samples were obtained from all patients before undergoing surgical biopsy. Liquid‐based cytology slides and cell‐blocks were prepared and assessed by cytomorphology and immunocytochemistry for four antibodies (Ki‐67, BAX, NF‐κB‐p65, and AMACR). For comparison purposes, a sub‐group of 31 matched surgical biopsy samples were selected randomly and assessed by immunohistochemistry. Patients were categorized according to their definitive diagnoses into OLP, OLL, and clinically lichenoid, but histopathologically dysplastic lesions (OEDL). Machine‐learning was utilized to provide automated quantification of positively stained protein expression.

Results

Cytomorphological assessment was associated with an accuracy of 77.27% in the distinction between OLP/OLL and OEDL. A strong concordance of 92.5% (κ = 0.84) of immunostaining patterns was evident between cell‐blocks and tissue sections using machine‐learning. A diagnostic index using a Ki‐67‐based model was 100% accurate in detecting lichenoid cases with epithelial dysplasia. A BAX‐based model demonstrated an accuracy of 92.16%. The accuracy of cytomorphological assessment was greatly improved when it was combined with BAX immunoreactivity (95%).

Conclusions

Cell‐blocks prepared from OLBC are reliable and minimally‐invasive alternatives to surgical biopsies to diagnose OLLs with epithelial dysplasia when combined with Ki‐67 immunostaining. Machine‐learning has a promising role in the automated quantification of immunostained protein expression.

Predicting Colorectal Cancer Occurrence in IBD

Patients with colonic inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC), and are therefore enrolled into a surveillance programme aimed at detecting dysplasia or early cancer. Current surveillance programmes are guided by clinical, endoscopic or histological predictors of colitis-associated CRC (CA-CRC). We have seen great progress in our understanding of these predictors of disease progression, and advances in endoscopic technique and management, along with improved medical care, has been mirrored by the falling incidence of CA-CRC over the last 50 years. However, more could be done to improve our molecular understanding of CA-CRC progression and enable better risk stratification for patients with IBD. This review summarises the known risk factors associated with CA-CRC and explores the molecular landscape that has the potential to complement and optimise the existing IBD surveillance programme.

p53 Expression as a Diagnostic Biomarker in Ulcerative Colitis-Associated Cancer

Ulcerative colitis (UC) is defined as an idiopathic inflammatory disorder primarily involving the mucosa and submucosa of the colon. UC-associated colon cancers (also known as colitic cancers) develop through the inflammation-dysplasia sequence, which is a major problem affecting the prognosis of patients with UC. It is therefore very important to detect malignancy from UC at an early stage. As precancerous lesions arising in UC, there are pathological adenomatous changes, basal cell changes, in situ anaplasia, clear cell changes, and pan-cellular change. It is considered that the mutation of the p53 gene plays a crucial role, and the protein expression of p53 in dysplastic crypts may serve as a good biomarker in the early stages of UC-associated colon carcinogenesis. Immunohistochemistry for p53 is a very valuable diagnostic tool in UC-associated colon cancers. However, protein expression of p53 is not always universal, and additional methods may be required to assess p53 status in UC-associated colon cancers.