Colorectal endometriosis - a challenging, often overlooked cause of colorectal pathology: a clinicopathological review of 114 cases.

The colon is the most common site for endometriosis outside the genital tract. It has a varied presentation and can mimic numerous other conditions, both clinically and pathologically. We investigated the clinicopathological features of a series of colorectal endometriosis with a particular emphasis on the features seen in cases with colonic mucosal involvement.

The Origin and Contribution of Cancer-Associated Fibroblasts in Colorectal Carcinogenesis.

Background & Aims: Cancer-associated fibroblasts (CAFs) play an important role in colorectal cancer (CRC) progression and predict poor prognosis in CRC patients. However, the cellular origins of CAFs remain unknown, making it challenging to therapeutically target these cells. Here, we aimed to identify the origins and contribution of colorectal CAFs associated with poor prognosis.

Traditional serrated adenoma-like lesions in patients with inflammatory bowel disease.

Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal carcinoma. The significance of serrated lesions resembling traditional serrated adenoma (TSA) in IBD patients is unclear. In this retrospective study, we analyzed 52 TSA-like lesions arising in 30 IBD patients and diagnosed in colectomy or endoscopic specimens.

DNA methylation changes that precede onset of dysplasia in advanced sessile serrated adenomas.

Background: Sessile serrated adenomas (SSAs) are common polyps which give rise to 20-30% of colorectal cancer (CRC). SSAs display clinicopathologic features which present challenges in surveillance, including overrepresentation in young patients, proclivity for the proximal colon and rarity of histologic dysplasia (referred to then as SSAs with dysplasia, SSADs). Once dysplasia develops, there is rapid progression to CRC, even at a small size.

CD96 Is an Immune Checkpoint That Regulates CD8 T-cell Antitumor Function.

CD96 is a novel target for cancer immunotherapy shown to regulate NK cell effector function and metastasis. Here, we demonstrated that blocking CD96 suppressed primary tumor growth in a number of experimental mouse tumor models in a CD8 T cell-dependent manner. DNAM-1/CD226, Batf3, IL12p35, and IFNγ were also critical, and CD96-deficient CD8 T cells promoted greater tumor control than CD96-sufficient CD8 T cells.

CpG Island Methylation in Sessile Serrated Adenomas Increases With Age, Indicating Lower Risk of Malignancy in Young Patients.

Among sessile serrated adenomas (SSAs) with identical histologic features, some never progress, whereas others become dysplastic and develop into invasive cancers. Development of the CpG island methylator phenotype is a feature of SSA progression; we examined the CIMP status of 448 SSAs and examined the association with patient clinical data. Overall, 190 SSAs were CpG island methylator phenotype-positive.

Genetic editing of colonic organoids provides a molecularly distinct and orthotopic preclinical model of serrated carcinogenesis.

Objective: Serrated colorectal cancer (CRC) accounts for approximately 25% of cases and includes tumours that are among the most treatment resistant and with worst outcomes. This CRC subtype is associated with activating mutations in the mitogen-activated kinase pathway gene, , and epigenetic modifications termed the CpG Island Methylator Phenotype, leading to epigenetic silencing of key tumour suppressor genes. It is still not clear which (epi-)genetic changes are most important in neoplastic progression and we begin to address this knowledge gap herein.

Sessile serrated adenomas with dysplasia: morphological patterns and correlations with MLH1 immunohistochemistry.

Sessile serrated adenomas are the precursor polyp of approximately 20% of colorectal carcinomas. Sessile serrated adenomas with dysplasia are rarely encountered and represent an intermediate step to malignant progression, frequently associated with loss of MLH1 expression. Accurate diagnosis of these lesions is important to facilitate appropriate surveillance, particularly because progression from dysplasia to carcinoma can be rapid.

GNAS mutations are present in colorectal traditional serrated adenomas, serrated tubulovillous adenomas and serrated adenocarcinomas with adverse prognostic features.

Aims: Activating mutations in GNAS are important in the development of a range of neoplasms, including a small proportion of conventional adenomas and colorectal carcinomas (CRCs). However, their contribution to serrated pathway neoplasia is unclear, as mutations have only been examined in small series of sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs), and not in serrated tubulovillous adenomas (sTVAs). The aim of this study was to investigate the frequency and significance of GNAS mutations in colorectal adenomas and CRCs.

Histopathological findings of extra-ileal manifestations at initial diagnosis of Crohn's disease-related ileitis.

Crohn's disease is a chronic inflammatory disorder that can affect any part of the gastrointestinal tract. Our objective was to review the histological findings in index biopsies from the terminal ileum and other gastro-intestinal tract sites of Crohn's disease patients prior any treatment and to compare them with the findings from patients with non-specific ileitis. A total of 111 consecutive Crohn's disease cases (55 females, median age 27 years) with extra-ileal biopsies were retrospectively selected.

RNF43 and ZNRF3 are commonly altered in serrated pathway colorectal tumorigenesis.

Serrated pathway colorectal cancers (CRCs) are characterised by a BRAF mutation and half display microsatellite instability (MSI). The Wnt pathway is commonly upregulated in conventional CRC through APC mutation. By contrast, serrated cancers do not mutate APC.

Adverse histological features in malignant colorectal polyps: a contemporary series of 239 cases.

Aims: Screening colonoscopy has led to more colorectal carcinomas presenting at an early stage potentially curable by endoscopic resection. In this study, we examined the clinical and histological features of a contemporary series of malignant colorectal polyps (MCPs) with subsequent surgical resection.

Methods: We conducted a retrospective study on a consecutive series of MCPs from 239 patients, predominantly males (57.

Traditional serrated adenoma: an update.

Although recognized 25 years ago, the traditional serrated adenoma (TSA) remains an ongoing source of diagnostic and biologic debate. Recent research has greatly improved our understanding of the morphological and molecular aspects of these polyps. In particular, the recognition of ectopic crypt foci (ECFs) in combination with typical cytology and slitlike serrations improves diagnostic reproducibility.

Methylation and expression of the tumour suppressor, PRDM5, in colorectal cancer and polyp subgroups.

Background: PRDM5 is an epigenetic regulator that has been recognized as an important tumour suppressor gene. Silencing of PRDM5 by promoter hypermethylation has been demonstrated in several cancer types and PRDM5 loss results in upregulation of the Wnt pathway and increased cellular proliferation. PRDM5 has not been extensively investigated in specific subtypes of colorectal cancers.

A clinicopathological and molecular analysis of 200 traditional serrated adenomas.

The traditional serrated adenoma is the least common colorectal serrated polyp. The clinicopathological features and molecular drivers of these polyps require further investigation. We have prospectively collected a cohort of 200 ordinary and advanced traditional serrated adenomas and performed BRAF and KRAS mutational profiling, CpG island methylator phenotype analysis, and immunohistochemistry for a panel of 7 antibodies (MLH1, β-catenin, p53, p16, Ki67, CK7, and CK20) on all cases.