Integrated genetic and epigenetic analysis of cancer-related genes in non-ampullary duodenal adenomas and intramucosal adenocarcinomas

Synchronous Multiple Primary Malignant Adenocarcinoma of the Descending Colon and Fungating Bleeding Adenocarcinoma of the Terminal Ileum Presenting Massive Rectal Bleeding: A Trap for the Unwary

Primary cancer of the ileum is rare, and when it occurs in conjunction with primary colon cancer, it becomes even more infrequent and challenging to diagnose prior to surgical intervention. Primary small bowel cancers can be overlooked and may be misidentified as small bowel mesenchymal tumours or advanced metastases from colon cancer. We present an exceedingly uncommon case of ruptured primary ileal cancer combined with primary descending colon cancer presenting with gastrointestinal bleeding. Based on our understanding, instances of dual tumours concurrently occurring are exceedingly infrequent. In this patient, there was a preoperative suspicion of bleeding from colon cancer in the descending region. However, intraoperative exploration revealed that the location of the bleeding was a terminal ileal mass. Following the surgical intervention, the patient recovered satisfactorily. Intraoperative exploration of the entire gastrointestinal tract is therefore necessary in patients with gastrointestinal haemorrhage, especially in those who require urgent surgery without adequate preoperative investigations. If a mass is detected at the end of the ileum, intraoperative pathology should be performed if feasible. Subsequently, if the diagnosis reveals an adenocarcinoma, terminal ileocolic resection and right hemicolectomy are necessary for appropriate resection.

Translating mechanisms into therapeutic strategies for immune thrombocytopenia (ITP): Lessons from clinical trials

Immune thrombocytopenia (ITP) is an autoimmune disorder that causes a significant reduction in peripheral blood platelet count. Fortunately, due to an increased understanding of ITP, there have been significant improvements in the diagnosis and treatment of these patients. Over the past decade, there have been a variety of proven therapeutic options available for ITP patients, including intravenous immunoglobulins (IVIG), Rituximab, corticosteroids, and thrombopoietin receptor agonists (TPO-RAs). Although the effectiveness of current therapies in treating more than two-thirds of patients, still some patients do not respond well to conventional therapies or fail to achieve long-term remission. Recently, a significant advancement has been made in identifying various mechanisms involved in the pathogenesis of ITP, leading to the development of novel treatments targeting these pathways. It seems that new agents that target plasma cells, Bruton tyrosine kinase, FcRn, platelet desialylation, splenic tyrosine kinase, and classical complement pathways are opening new ways to treat ITP. In this study, we reviewed the pathophysiology of ITP and summarized updates in this population's management and treatment options. We also took a closer look at the 315 ongoing trials to investigate their progress status and compare the effectiveness of interventions. May our comprehensive view of ongoing clinical trials serve as a guiding beacon, illuminating the path towards future trials of different drugs in the treatment of ITP patients.

Relationship Between Immunophenotypes, Genetic Profiles, and Clinicopathologic Characteristics in Small Bowel Adenocarcinoma

Small bowel adenocarcinoma (SBA) is rare, and scant data exist regarding its molecular and clinicopathologic characteristics. This study aimed to clarify the correlation between immunophenotypes, DNA mismatch repair status, genomic profiling, and clinicopathologic characteristics in patients with SBA. We examined 68 surgical resections from patients with primary SBA for immunohistochemical analyses of CK7, CK20, CD10, CDX2, MUC1, MUC2, MUC4, MUC5AC, and MUC6 expression as well as mismatch repair status. Genomic profiling was performed on 30 cases using targeted next-generation sequencing. Tumor mucin phenotypes were classified as gastric, intestinal, gastrointestinal, or null based on MUC2, MUC5AC, MUC6, and CD10 immunostaining. The expression of these proteins was categorized into 3 classifications according to their relationship to: (1) tumor location: CK7/CK20, MUC4, and MUC6; (2) histologic type: mucinous adenocarcinoma was positive for MUC2 and negative for MUC6; and (3) TNM stage: CD10 was downregulated, whereas MUC1 was upregulated in advanced TNM stages. CDX2 was a specific marker for SBA generally expressed in the small intestine. MUC1 and MUC4 expression was significantly associated with worse prognosis. MUC2 expression correlated with better prognosis, except for mucinous adenocarcinoma. Although the difference was not statistically significant, gastric-type tumors were more frequently located in the duodenum and were absent in the ileum. APC and CTNNB1 mutations were not found in the gastric-type tumors. The SBA immunophenotype correlated with tumor location, biological behavior, and genomic alterations. Our results suggest that the molecular pathway involved in carcinogenesis of gastric-type SBA differs from that of intestinal-type SBA.

Identifying novel interactions of the colon-cancer related APC protein with Wnt-pathway nuclear transcription factors

BACKGROUND

Colon cancer is often driven by mutations of the adenomatous polyposis coli (APC) gene, an essential tumor suppressor gene of the Wnt β-catenin signaling pathway. APC and its cytoplasmic interactions have been well studied. However, various groups have also observed its presence in the nucleus. Identifying novel interactions of APC in the Wnt pathway will provide an opportunity to understand APC's nuclear role better and ultimately identify potential cancer treatment targets.

METHODS

We used the all-vs-all sequencing (AVA-Seq) method to interrogate the interactome of protein fragments spanning most of the 60 Wnt β-catenin pathway proteins. Using protein fragments identified the interacting regions between the proteins with more resolution than a full-length protein approach. Pull-down assays were used to validate a subset of these interactions.

RESULTS

74 known and 703 novel Wnt β-catenin pathway protein-protein interactions were recovered in this study. There were 8 known and 31 novel APC protein-protein interactions. Novel interactions of APC and nuclear transcription factors TCF7, JUN, FOSL1, and SOX17 were particularly interesting and confirmed in validation assays.

CONCLUSION

Based on our findings of novel interactions between APC and transcription factors and previous evidence of APC localizing to the nucleus, we suggest APC may compete and repress CTNNB1. This would occur through APC binding to the transcription factors (JUN, FOSL1, TCF7) to regulate the Wnt signaling pathway including through enhanced marking of CTNNB1 for degradation in the nucleus by APC binding with SOX17. Additional novel Wnt β-catenin pathway protein-protein interactions from this study could lead researchers to novel drug designs for cancer.

Genetic analysis of Japanese patients with small bowel adenocarcinoma using next-generation sequencing

BACKGROUND

Small bowel adenocarcinomas (SBAs) are rare and there is little comprehensive data on SBA genomic alterations for Asian patients. This study aimed to profile genomic alterations of SBA in Japanese patients using targeted next-generation sequencing (NGS).

METHODS

We examined 22 surgical resections from patients with primary SBA. SBA genomic alterations were analyzed by NGS. Mismatch repair (MMR) status was determined by immunohistochemical analysis. Mucin phenotypes were classified as gastric (G), intestinal (I), gastrointestinal (GI), and null (N) types on MUC2, MUC5AC, MUC6, and CD10 immunostaining.

RESULTS

The most common genomic alterations found in SBA tumors were TP53 (n = 16), followed by KRAS (n = 6), APC (n = 5), PIK3CA (n = 4), CTNNB1 (n = 3), KIT (n = 2), BRAF (n = 2), CDKN2A (n = 2), and PTEN (n = 2). Deficient MMR tumors were observed in 6 out of 22 patients. Tumor mucin phenotypes included 2 in G-type, 12 in I-type, 3 in GI-type, and 5 in N-type. APC and CTNNB1 mutations were not found in G-type and GI-type tumors. KRAS mutations were found in all tumor types except for G-type tumors. TP53 mutations were found in all tumor types. Although no single gene mutation was associated with overall survival (OS), we found that KRAS mutations were associated with significant worse OS in patients with proficient MMR tumors.

CONCLUSIONS

SBA genomic alterations in Japanese patients do not differ significantly from those reports in Western countries. Tumor localization, mucin phenotype, and MMR status all appear to impact SBA gene mutations.

Relationship between gene mutations and clinicopathological features in nonampullary duodenal epithelial tumors

BACKGROUND

Molecular features of nonampullary duodenal epithelial tumors (NADETs) remain unclear.

AIM

The aim of this study is to determine the association between the genetic features and clinicopathological findings of NADETs.

METHODS

In total, 75 NADETs were enrolled in this study, and was performed targeted DNA sequencing of the GNAS, KRAS, TP53, and APC genes. Histological grade was classified as category 3 or category 4/5 according to the Vienna classification, and the immunophenotype was categorized as the gastric phenotype (G type), gastrointestinal phenotype (GI type), or the intestinal phenotype (I type).

RESULTS

The prevalence of GNAS and KRAS mutations was significantly higher in the G type than in the GI/I type (GNAS, P = 0.027; KRAS, P = 0.005). In contrast, the frequency of TP53 mutations was significantly higher in the GI/I type than in the G type (P = 0.049). Notably, APC mutations, excluding c.4479 G>A which was synonymous mutation, were more frequently identified in category 4/5 tumors than in category 3 tumors (50% vs. 24.5%; P = 0.039).

CONCLUSION

G-type NADETs harbored frequent GNAS and KRAS mutations, whereas TP53 mutations are common in NADETs with intestinal features. APC mutations were significantly associated with high-grade neoplasia and invasive carcinoma.

The role of epigenetics in childhood autoimmune diseases with hematological manifestations

Autoimmune diseases with hematological manifestations are often characterized by chronicity and relapses despite treatment, and the underlying pathogenetic mechanisms remain unknown. Epigenetic alterations play a vital role in the deregulation of immune tolerance and the development of autoimmune diseases. In recent years, study of epigenetic mechanisms in both adult and childhood autoimmune disorders has been seeking to explain the pathophysiology of these heterogeneous diseases and to elucidate the interaction between genetic and environmental factors. Various mechanisms, including DNA methylation, histone modifications (chromatin remodeling), and noncoding RNAs (ncRNAs), have been studied extensively in the context of autoimmune diseases. This paper summarizes the epigenetic patterns in some of the most common childhood autoimmune disorders with hematological manifestations, based on epigenetic studies in children with primary immune thrombocytopenia (ITP), systemic lupus erythematosus (SLE), and juvenile idiopathic arthritis (JIA). Research findings indicate that methylation changes in genes expressed on T cells, modifications at a variety of histone sites, and alterations in the expression of several ncRNAs are involved in the pathogenesis of these diseases. These mechanisms not only determine the development of these diseases but also affect the severity of the clinical presentation and biochemical markers. Further studies will provide new tools for the prevention and diagnosis of childhood autoimmune disorders, and possible novel treatment options.

Histologic heterogeneity and syndromic associations of non-ampullary duodenal polyps and superficial mucosal lesions

BACKGROUND

Duodenal polyps and superficial mucosal lesions (DP/SMLs) are poorly characterised.

AIMS

To describe a series of endoscopically-diagnosed extra-ampullary DPs/SMLs.

METHODS

This is a retrospective study conducted in a tertiary referral Endoscopy Unit, including patients who had DPs or SMLs that were biopsied or removed in 2010-2019. Age, gender, history of familial polyposis syndromes, DP/SML characteristics were recorded. Histopathological, immunohistochemical and molecular analyses were performed.

RESULTS

399 non-ampullary DP/SMLs from 345 patients (60.6% males; median age 67 years) were identified. Gastric foveolar metaplasia represented the most frequent histotype (193 cases, 48.4%), followed by duodenal adenomas (DAs; 77 cases, 19.3%). Most DAs (median size 6 mm) were sessile (Paris Is; 48%), intestinal-type (96.1%) with low-grade dysplasia (93.5%). Among syndromic DAs (23%), 15 lesions occurred in familial adenomatous polyposis 1, two were in MUTYH-associated polyposis and one was in Peutz-Jeghers syndrome (foveolar-type, p53-positive, low-grade dysplasia). Only one (3.3%) tubular, low-grade DA showed mismatch repair deficiency (combined loss of MLH1 and PMS2, heterogeneous MSH6 expression), and it was associated with a MLH1 gene germline mutation (Lynch syndrome).

CONCLUSION

DPs/SMLs are heterogeneous lesions, most of which showing foveolar metaplasia, followed by low-grade, intestinal-type, non-syndromic DAs. MMR-d testing may identify cases associated with Lynch syndrome.

Nonampullary Duodenal Adenomas in Familial Adenomatous Polyposis and Sporadic Patients Lack the DNA Content Abnormality That Is Characteristic of the Adenoma-Carcinoma Sequence Involved in the Development of Other Gastrointestinal Malignancies

Nonampullary duodenal adenomas (NADAs) develop sporadically or in the setting of a hereditary syndrome such as familial adenomatous polyposis (FAP). Although they are thought to progress into duodenal adenocarcinomas via an adenoma to carcinoma sequence similar to colorectal cancer, limited data suggested that they may be biologically dissimilar to colorectal adenomas. The clinicopathologic features of 71 patients diagnosed with NADAs (37 FAP and 34 sporadic) were analyzed. From the 71 patients, 89 NADA biopsies (42 FAP and 47 sporadic) were evaluated by DNA flow cytometry. Eighty-two samples showed low-grade dysplasia, and 7 demonstrated high-grade dysplasia (HGD). Twenty-one low-grade adenomas of the ileal pouch (n=19) and jejunum (n=2) from 15 FAP patients who underwent total proctocolectomy were also analyzed by DNA flow cytometry. The FAP patients were more likely to be younger (mean: 28 y) and have multifocal disease (92%) than the sporadic patients (66 y and 24%, respectively) (P<0.001). Most NADAs presented as polypoid lesions (87%) in the duodenal bulb and/or second portion of the duodenum (94%). Sporadic NADAs (mean: 2.4 cm) were significantly larger than FAP-related NADAs (1.3 cm) (P=0.005). Three (4%) patients (2 sporadic and 1 FAP) had high-grade NADAs at the first endoscopy, while the remaining 68 (96%) patients had low-grade dysplasia. Two additional sporadic and 1 FAP patients developed HGD on follow-up. Although the overall detection rate of advanced neoplasia (either HGD or adenocarcinoma) was similar between the FAP (n=5; 14%) and sporadic groups (n=4; 12%) (P=1.000), 3 FAP patients (all with Spigelman stage III to IV) developed adenocarcinoma in the duodenum (n=2) or in the ileal pouch (n=1) within a mean follow-up time of 76 months, while no adenocarcinoma was found in the sporadic group. Of the 37 FAP patients, 29 (78%) had a history of total proctocolectomy, and 15 (52%) developed low-grade adenomas in the ileal pouch with (n=2) or without (n=13) jejunal involvement (vs. 0% in the sporadic patients, P<0.001). All 15 patients had ≥Spigelman stage II. Aneuploidy was detected in only 1 (1%) sporadic NADA with HGD, whereas the remaining 109 duodenal, ileal pouch, and jejunal adenomas showed normal DNA content. The overall 3-, 9-, and 15-year detection rates of adenocarcinoma (in the duodenum and ileal pouch) in all NADA patients were 1.4%, 7.2%, and 18.8%, respectively. Three-, 9-, and 15-year detection rates of adenocarcinoma in the FAP patients were 2.7%, 9.7%, and 22.6%, respectively, while these rates remained at 0% in the sporadic patients. In conclusion, FAP-related NADAs have distinct clinicopathologic features compared with their sporadic counterpart. However, the vast majority of both FAP-related and sporadic NADAs (99%) lack the DNA content abnormality that is characteristic of the typical adenoma-carcinoma sequence involved in other gastrointestinal carcinogenesis. Although adenocarcinoma is more likely to develop in FAP patients with a high adenoma burden, probably due to the higher likelihood that some advanced lesions are missed endoscopically, FAP-related and sporadic NADAs may have a comparable risk of developing advanced neoplasia on a per-adenoma basis.

APC mutations are common in adenomas but infrequent in adenocarcinomas of the non-ampullary duodenum

BACKGROUND

Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear.

METHODS

We analyzed 144 adenomas and 54 adenocarcinomas of the non-ampullary duodenum for immunohistochemical phenotypes, genetic alterations, and mismatch repair (MMR) status to probe their histogenetic relationship.

RESULTS

The median ages of patients with adenoma and adenocarcinoma were the same (66 years). Adenomas were histologically classified as intestinal-type adenoma (n = 124), pyloric gland adenoma (PGA, n = 10), gastric-type adenoma, not otherwise specified (n = 9), and foveolar-type adenoma (n = 1). Protein-truncating APC mutations were highly frequent in adenomas (85%), with the highest prevalence in intestinal-type adenomas (89%), but rare in adenocarcinomas (9%; P = 2.1 × 10^-23). Close associations between phenotypic marker expression and genetic alterations were observed in adenomas, but not in adenocarcinomas, excluding the common association between GNAS mutations and MUC5AC expression. MMR deficiency was more frequent in adenocarcinomas (20%) than in adenomas (1%; P = 2.6 × 10^-6). One MMR-deficient adenoma and three MMR-deficient adenocarcinomas occurred in patients with Lynch syndrome. Additionally, three other patients with an MMR-deficient adenocarcinoma fulfilled the revised Bethesda criteria.

CONCLUSION

The discrepant APC mutation frequency between adenomas and adenocarcinomas suggests that APC-mutated adenomas, which constitute the large majority of non-ampullary duodenal adenomas, are less prone to malignant transformation. Non-ampullary duodenal adenocarcinomas frequently exhibit MMR deficiency and should be subject to MMR testing to determine appropriate clinical management, including the identification of patients with Lynch syndrome.

Risk Factors for Non-Ampullary Duodenal Adenocarcinoma: A Systematic Review

INTRODUCTION

An increase in the incidence of duodenal adenocarcinoma has been recently reported. However, little is known about the risk factors for duodenal adenocarcinoma, which are important for screening purposes. We, therefore, aimed to conduct a systematic review to identify risk factors for non-ampullary duodenal adenocarcinoma.

METHODS

A medical literature search was performed using electronic databases, including PubMed, Cochrane Library, Japan Medical Abstracts Society, and Web of Science. Studies that assessed the association between dietary habits, lifestyle behaviors, comorbidities, and non-ampullary duodenal adenocarcinoma were extracted. The Newcastle-Ottawa Scale was used to assess the risk of bias in individual studies, and the Grading of Recommendations, Assessment, Development, and Evaluations approach was used to assess the quality of evidence across studies included in this review.

RESULTS

Out of 1,244 screened articles, 10 were finally selected for qualitative synthesis. In the general population, no consistent risk factors were identified except for Helicobacter pylori positivity, which was considered a risk factor in 2 studies, but the quality of evidence was considered very low because of the high risk of bias. In patients with familial adenomatous polyposis (FAP), Spigelman stage IV at initial endoscopy was considered a consistent risk factor in 3 studies.

CONCLUSIONS

There are currently limited data regarding risk factors for non-ampullary duodenal adenocarcinoma, and no conclusive risk factors were identified in the general population. However, in patients with FAP, Spigelman stage IV was identified as a consistent risk factor. Further studies are needed to improve diagnosis and support effective clinical management of this malignancy.

Small Bowel Epithelial Precursor Lesions: A Focus on Molecular Alterations

The wider use of gastrointestinal endoscopic procedures has led to an increased detection of small intestinal preneoplastic and neoplastic epithelial lesions, most of which are identified in the duodenum and ampullary region. Like their malignant counterparts, small intestinal glandular precursor lesions, which include adenomas and hamartomas, may arise sporadically or be associated with hereditary tumor syndromes, such as familial adenomatous polyposis, MUTYH-associated polyposis, Lynch syndrome, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome. In addition, dysplastic, preinvasive lesions have been observed adjacent to small bowel adenocarcinomas complicating immune-related disorders, such as celiac or Crohn’s disease. Adenomatous lesions may exhibit an intestinal-type, gastric-type, or, very rarely, serrated differentiation, related to different molecular pathogenetic mechanisms. Finally, in the background of multiple endocrine neoplasia 1 syndrome, precursor neuroendocrine growths have been described. In this review we offer a comprehensive description on the histo-molecular features of the main histotypes of small bowel epithelial precursors lesions, including: (i) sporadic adenomas (intestinal-type and gastric-type; non-ampullary and ampullary); (ii) syndromic adenomas; (iii) small bowel dysplasia in celiac and Crohn’s disease; (iv) serrated lesions; (v) hamartomatous lesions; and (vi) neuroendocrine precursor lesions.

Extensive molecular reclassification: new perspectives in small bowel adenocarcinoma?

SBA classification is still based on the location of the primary tumor, without genetic information. in the current study, an extensive genetic profile of SBA, was performed in order to identify and quantify targetable alterations for a future precision medicine in SBA. Clinical-pathological information for 24 patients affected by SBA were retrospectively reviewed. Whole genome analysis of the primary tumors was performed by the FOUNDATION Cdx technology. We carried out a functional enrichment analysis of the mutated genes with BioPlanet. Integrative clustering analysis revealed three distinct subtypes characterized by different genomic alterations. Cluster 1exhibited significant correlations with MSI status, high TMB, celiac disease and Jejunual site.We defined cluster 1 as "immunological subtype" (29.2% of patients). Driver mutations in this subtype suggest that 100% of patients may benefit from immunotherapy. Enrichment analysis of cluster 2 highlighted that the main affected pathway was that of homologous DNA pairing and strand exchange (16.7% of patients). We defined this cluster as "DNA Damage Repair (DDR) like". On the basis of these driver molecular alterations, 100% of patients could benefit from PARPi. Finally, Cluster 3 had no significant correlations with clinical-pathological characteristics (54.1% of patients). Enrichment analysis revealed that this cluster has remarkable similarities with CRA genomic profile, so we defined it as "Colon-like". SBA is a genetically distinct tumor entity and deep mutation heterogeneity indicates that different driver genes play a role in the biology of these tumors. The identification of clusters based on genetic profile suggest the possibility to go beyond chemotherapy in several patients.