The serrated pathway to colorectal carcinoma: current concepts and challenges

The anti-colorectal cancer effect and metabolites of Agrimonia pilosa Ledeb

ETHNOPHARMACOLOGICAL RELEVANCE

Agrimonia pilosa Ledeb. (Rosaceae, A. pilosa) has been used in traditional medicine in China, Japan, Korea, and other Asian countries for treatment of acute and chronic enteritis and diarrhea. Secondary metabolites have been isolated and tested for biological activities. It remains unclear in terms of its potential components of anti-colorectal cancer properties.

AIM OF THE STUDY

The study aimed to how extracts from A. pilosa and their components influenced tumor microenvironment and the colorectal tumor growth in vivo on AOM/DSS induced colorectal cancer mice, the metabolites of A. pilosa was also been studied.

MATERIALS AND METHODS

Different methods have been used to extract different parts of A. pilosa. And the anti-proliferation effect of these extracts on colon cancer cells have been tested. The components of A. pilosa and its metabolites in vivo were analyzed by UPLC-QTOF-MS/MS. The anti-colorectal cancer (CRC) effects of A. pilosa and its components in vivo were studied on AOM/DSS induced CRC mice. The effects of constituents of A. pilosa on the composition of immune cells in tumor microenvironment (TME) were analyzed by flow cytometry. 16 S rDNA technology was used to analyze the effect of administration on the composition of intestinal microflora. Pathological section staining was used to compare the morphological changes and molecular expression of intestinal tissue in different groups.

RESULTS

The constituent exists in root of A. pilosa showed the strongest anti-proliferation ability on colon cancer cells in vitro. The extract from the root of A. pilosa could attenuate the occurrence of colorectal tumors induced by AOM/DSS in a concentration-dependent manner. Administration of the extract from the root of A. pilosa could affect the proportion of γδT cells, tumor associated macrophages and myeloid derived suppressor cells in TME, increasing the proportion of anti-tumor immune cells and decrease the immunosuppressive cells in the TME to promote the anti-tumor immune response. The administration of the extract adjusted the composition of gut microbiota and its components Agrimoniin and Agrimonolide-6-o-glucoside showed the strongest anti-CRC effect in vivo with adjusting the gut microbiota differently.

CONCLUSIONS

The extract from root of A. pilosa showed anti-colorectal cancer effects in vivo and in vitro, affecting the composition of gut microbiota and the anti-tumor immune response. Within all components of A. pilosa, Agrimoniin and Agrimonolide-6-o-glucoside showed remarkable anti-CRC efficiency in vivo and in vitro. Besides, the metabolites of extract from root of A. pilosa in gastrointestinal tract mainly composed of two parts: Agrimonolide-related metabolites and Urolithins. The extract from root of A. pilosa could contribute to potential drugs for assisting clinical anti-colon cancer therapy.

Unmasking early colorectal cancer clues: in silico and in vitro investigation of downregulated IGF2, SOCS1, MLH1, and CACNA1G in SSA polyps

BACKGROUND AND AIM

Colorectal cancer (CRC) originates from pre-existing polyps in the colon. The development of different subtypes of CRC is influenced by various genetic and epigenetic characteristics. CpG island methylator phenotype (CIMP) is found in about 15-20% of sporadic CRCs and is associated with hypermethylation of certain gene promoters. This study aims to find prognostic genes and compare their expression and methylation status as potential biomarkers in patients with serrated sessile adenomas/polyps (SSAP) and CRC, in order to evaluate which, one is a better predictor of disease.

METHOD

This study employed a multi-phase approach to investigate genes associated with CRC and SSAP. Initially, two gene expression datasets were analyzed using R and Limma package to identify differentially expressed genes (DEGs). Venn diagram analysis further refined the selection, revealing four genes from the Weissenberg panel with significant changes. These genes, underwent thorough in silico evaluations. Once confirmed, they proceeded to wet lab experimentation, focusing on expression and methylation status. This comprehensive methodology ensured a robust examination of the genes involved in CRC and SSAP.

RESULT

This study identified cancer-specific genes, with 8,351 and 1,769 genes specifically down-regulated in SSAP and CRC tissues, respectively. The down-regulated genes were associated with cell adhesion, negative regulation of cell proliferation, and drug response. Four highly downregulated genes in the Weissenberg panel, including CACNA1G, IGF2, MLH1, and SOCS1. In vitro analysis showed that they are hypermethylated in both SSAP and CRC samples while their expressions decreased only in CRC samples.

CONCLUSION

This suggests that the decrease in gene expression could help determine whether a polyp will become cancerous. Using both methylation status and gene expression status of genes in the Weissenberg panel in prognostic tests may lead to better prognoses for patients.

Endoscopic characteristics and performance of WASP classification in the diagnosis of colorectal sessile-serrated lesions in Vietnamese patients

Background/Aims

Sessile-serrated lesions (SSLs) are challenging to detect due to their typically subtle appearance. The Workgroup serrAted polypS and Polyposis (WASP) classification was developed to diagnose SSLs endoscopically. This study aimed to evaluate the endoscopic characteristics of SSLs and the performance of the WASP classification in the Vietnamese population.

Methods

This cross-sectional study was carried out on patients with lower gastrointestinal symptoms who underwent colonoscopy at a Vietnamese tertiary hospital. Univariate and multivariate analyses were performed to identify endoscopic features associated with SSLs. The performance of the WASP classification for diagnosing SSLs was assessed, and SSLs were diagnosed according to the 2019 World Health Organization (WHO) criteria.

Results

There were 2489 patients, with a mean age of 52.1 ± 13.1 years and a female-to-male ratio of 1:1.1. A total of 121 specimens from 105 patients were diagnosed with SSLs. According to multivariate analysis, the endoscopic features significantly associated with SSLs were proximal location (odds ratio [OR]: 2.351; 95% confidence interval [CI]: 1.475-3.746), size >5 mm (OR: 2.447; 95% CI: 1.551-3.862), flat morphology (OR: 2.781; 95% CI: 1.533-5.044), irregular shape (OR: 4.516; 95% CI: 2.173-9.388), varicose microvascular vessels (OR: 5.030; 95% CI: 2.657-9.522), and dark spots inside the crypts (OR: 5.955; 95% CI: 3.291-10.776). The accuracy of the WASP classification for diagnosing SSLs was 94.0% (95% CI: 92.8%-95.0%).

Conclusion

Proximal location, size >5 mm, flat morphology, irregular shape, varicose microvascular vessels, and dark spots inside the crypts were significantly associated with SSLs. The WASP classification had high accuracy in the diagnosis of SSLs.

The Comparison of Diagnostic Ability between Blue Laser/Light Imaging and Narrowband Imaging for Sessile Serrated Lesions with or without Dysplasia

Objectives

Diagnostic ability of sessile serrated lesions (SSL) and SSL with dysplasia (SSLD) using blue laser/light imaging (BLI) has not been well examined. We analyzed the diagnostic accuracy of BLI for SSL and SSLD using several endoscopic findings compared to those of narrow band imaging (NBI).

Materials and Methods

This was a subgroup analysis of prospective studies. 476 suspiciously serrated lesions of ≥2 mm on the proximal colon showing serrated change with magnified NBI or BLI in our institution between 2014 and 2021 were examined histopathologically. After propensity score matching, we evaluated the diagnostic ability of SSL and SSLD of the NBI and BLI groups regarding various endoscopic findings. For WLI findings, granule, depression, and reddish were examined for diagnosing SSLD. For NBI/BLI findings, expanded crypt opening (ECO) or thick and branched vessels (TBV) were examined for diagnosing SSL. Network vessels (NV) and white dendritic change (WDC) defined originally were examined for diagnosing SSLD.

Results

Among matched 176 lesions, the sensitivity of lesions with either ECO or TBV for SSL in the NBI/BLI group was 97.5%/98.5% (p = 0.668). Those with either WDC or NV for diagnosing SSLD in the groups were 81.0%/88.9% (p = 0.667). Regarding the rates of endoscopic findings among 30 SSLD and 290 SSL, there were significant differences in WDC (66.4% vs. 8.6%, p < 0.001), NV (55.3% vs. 1.4%, p < 0.001), and either WDC or NV (86.8% vs. 9.0%, p < 0.001).

Conclusions

The diagnostic ability of BLI for SSL and SSLD was not different from NBI. NV and WDC were useful for diagnosing SSLD.

The CpG Island Methylator Phenotype Status in Synchronous and Solitary Primary Colorectal Cancers: Prognosis and Effective Therapeutic Drug Prediction

Synchronous colorectal cancer (sCRC) is characterized by the occurrence of more than one tumor within six months of detecting the first tumor. Evidence suggests that sCRC might be more common in the serrated neoplasia pathway, marked by the CpG island methylator phenotype (CIMP), than in the chromosomal instability pathway (CIN). An increasing number of studies propose that CIMP could serve as a potential epigenetic predictor or prognostic biomarker of sCRC. Therapeutic drugs already used for treating CIMP-positive colorectal cancers (CRCs) are reviewed and drug selections for sCRC patients are discussed.

Impact of Clinical and Endoscopic Features on the Development of Metachronous Colorectal Advanced Serrated Lesions

BACKGROUND AND AIMS

High-risk adenomas predict metachronous advanced adenomatous neoplasia. Limited data exist on predictors of metachronous advanced serrated lesions (mASLs). We analyzed clinical and endoscopic predictors of mASLs.

METHODS

In this retrospective cohort study, adults with >1 outpatient colonoscopy between 2008 and 2019 at a tertiary center were included. Serrated lesions (SLs) included sessile SLs (SSLs), traditional serrated adenomas (TSAs), and hyperplastic polyps (HPs). Patient and endoscopic characteristics were obtained using electronic medical records. Five-year cumulative incidence of mASL (HP ≥10 mm, SSL ≥10 mm or with dysplasia, any TSA) and factors associated with mASL were evaluated using Kaplan-Meier estimates and Cox proportional hazards models.

RESULTS

A total of 4990 patients were included and 45.4% were women. Mean age was 60.9 ± 9.2 years and median follow-up time was 3.7 years. Female sex and active smoking were associated with mASL. Endoscopically, any SSL and TSA were associated with mASL. The 5-year cumulative incidence for mASL was 26% (95% confidence interval [CI], 18%-32%) for SSL ≥10 mm, 17% (95% CI, 3.5%-29%) for HP ≥10 mm, 21% (95% CI, 0%-42%) for 3-4 SSLs <10 mm, 18% (95% CI, 0%-38%) for TSA, and 27% (95% CI, 3.6%-45%) for SSL with low-grade dysplasia. Baseline synchronous nonadvanced SL and nonadvanced adenoma were not associated with mASL.

CONCLUSIONS

Our data support current recommendations for a 3-year surveillance interval in patients with baseline SSL ≥10 mm, SSL with dysplasia, and TSA. A 3-year interval may be more appropriate than 3-5 years for patients with baseline HP ≥10 mm or 3-4 SSLs <10 mm. Patients with synchronous nonadvanced SLs and adenomas do not appear to be at increased risk of mASL.

Deficient mismatch repair screening of advanced adenomas in the population screening program for colorectal cancer is not effective

AIM

Currently, screening of colorectal cancers (CRC) by assessing mismatch repair deficiency (dMMR) or microsatellite instability (MSI) is used to identify Lynch syndrome (LS) patients. Advanced adenomas are considered immediate precursor lesions of CRC. In this study we investigate the relevance of screening of advanced adenomas for LS in population screening.

METHODS AND RESULTS

Advanced adenomas (n = 1572) were selected from the Dutch colorectal cancer population screening programme, based on one or more of the criteria: tubulovillous (n = 848, 54%) or villous adenoma (n = 118, 7.5%), diameter ≥ 1 cm (n = 1286, 82%) and/or high-grade dysplasia (n = 176, 11%). In 86 cases (5%), all three criteria were fulfilled at the same time. MMR-IHC and/or MSI analyses were performed on all cases. Only five advanced adenomas (0.3%) showed dMMR and MSI, including two cases with hypermethylation. In at least two patients a germline event was suspected based on allelic frequencies. No pathogenic explanation was found in the last case.

CONCLUSION

Timely testing of precursor lesions would be preferable to detect new LS patients before CRC development. However, standard assessment of dMMR of advanced adenomas from the population screening is not effective.

A simplified algorithm to evaluate the risk of submucosal invasive cancer in large (≥20 mm) nonpedunculated colonic polyps

BACKGROUND

Recognition of submucosal invasive cancer (SMIC) in large (≥20 mm) nonpedunculated colonic polyps (LNPCPs) informs selection of the optimal resection strategy. LNPCP location, morphology, and size influence the risk of SMIC; however, currently no meaningful application of this information has simplified the process to make it accessible and broadly applicable. We developed a decision-making algorithm to simplify the identification of LNPCP subtypes with increased risk of potential SMIC.

METHODS

Patients referred for LNPCP resection from September 2008 to November 2022 were enrolled. LNPCPs with SMIC were identified from endoscopic resection specimens, lesion biopsies, or surgical outcomes. Decision tree analysis of lesion characteristics identified in multivariable analysis was used to create a hierarchical classification of SMIC prevalence.

RESULTS

2451 LNPCPs were analyzed: 1289 (52.6%) were flat, 1043 (42.6%) nodular, and 118 (4.8%) depressed. SMIC was confirmed in 273 of the LNPCPs (11.1%). It was associated with depressed and nodular vs. flat morphology (odds ratios [ORs] 35.7 [95%CI 22.6-56.5] and 3.5 [95%CI 2.6-4.9], respectively; P<0.001); rectosigmoid vs. proximal location (OR 3.2 [95%CI 2.5-4.1]; P<0.001); nongranular vs. granular appearance (OR 2.4 [95%CI 1.9-3.1]; P<0.001); and size (OR 1.12 per 10-mm increase [95%CI 1.05-1.19]; P<0.001). Decision tree analysis targeting SMIC identified eight terminal nodes: SMIC prevalence was 62% in depressed LNPCPs, 19% in nodular rectosigmoid LNPCPs, and 20% in nodular proximal colon nongranular LNPCPs.

CONCLUSIONS

This decision-making algorithm simplifies identification of LNPCPs with an increased risk of potential SMIC. When combined with surface optical evaluation, it facilitates accurate lesion characterization and resection choices.

Analysis of the Characteristics of Coexisting Lesions in Colorectal Cancer Patients in an International Study: A Subgroup Analysis of the ATLAS Trial

INTRODUCTION

We investigated coexisting lesion types in patients with invasive colorectal cancer (CRC) in a multinational study for comprehending the adenoma-carcinoma and serrated pathway about the development of CRC.

METHODS

We retrospectively reviewed 3,050 patients enrolled in the international randomized controlled trial (ATLAS study) to evaluate the colorectal polyp detection performance of image-enhanced endoscopy in 11 institutions in four Asian countries/regions. In the current study, as a subgroup analysis of the ATLAS study, 92 CRC patients were extracted and compared to 2,958 patients without CRC to examine the effects of age, sex, and coexisting lesion types (high-grade adenoma [HGA], low-grade adenoma with villous component [LGAV], 10 adenomas, adenoma ≥10 mm, sessile serrated lesions [SSLs], and SSLs with dysplasia [SSLD]). Additional analyses of coexisting lesion types were performed according to sex and location of CRC (right- or left-sided).

RESULTS

A multivariate analysis showed that HGA (odds ratio [95% confidence interval] 4.29 [2.16-8.18]; p < 0.01), LGAV (3.02 [1.16-7.83], p = 0.02), and age (1.04 [1.01-1.06], p = 0.01) were independently associated with CRC. According to sex, the coexisting lesion types significantly associated with CRC were LGAV (5.58 [1.94-16.0], p < 0.01) and HGA (4.46 [1.95-10.20], p < 0.01) in males and HGA (4.82 [1.47-15.80], p < 0.01) in females. Regarding the location of CRC, SSLD (21.9 [1.31-365.0], p = 0.03) was significant for right-sided CRC, and HGA (5.22 [2.39-11.4], p < 0.01) and LGAV (3.46 [1.13-10.6], p = 0.02) were significant for left-sided CRC.

CONCLUSIONS

The significant coexisting lesions in CRC differed according to sex and location. These findings may contribute to comprehending the pathogenesis of CRC.

Exploring the role of sporadic BRAF and KRAS mutations during colorectal cancer pathogenesis: A spotlight on the contribution of the endosome-lysosome system

The highly heterogenous nature of colorectal cancer can significantly hinder its early and accurate diagnosis, eventually contributing to high mortality rates. The adenoma-carcinoma sequence and serrated polyp-carcinoma sequence are the two most common sequences in sporadic colorectal cancer. Genetic alterations in adenomatous polyposis coli (APC), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and tumour protein 53 (TP53) genes are critical in adenoma-carcinoma sequence, whereas v-Raf murine sarcoma viral oncogene homolog B (BRAF) and MutL Homolog1 (MLH1) are driving oncogenes in the serrated polyp-carcinoma sequence. Sporadic mutations in these genes contribute differently to colorectal cancer pathogenesis by introducing distinct alterations in several signalling pathways that rely on the endosome-lysosome system. Unsurprisingly, the endosome-lysosome system plays a pivotal role in the hallmarks of cancer and contributes to specialised colon function. Thus, the endosome-lysosome system might be distinctively influenced by different mutations and these alterations may contribute to the heterogenous nature of sporadic colorectal cancer. This review highlights potential connections between major sporadic colorectal cancer mutations and the diverse pathogenic mechanisms driven by the endosome-lysosome system in colorectal carcinogenesis.

Sporadic Polyps of the Colorectum

Colorectal polyps are common, and their diagnosis and classification represent a major component of gastrointestinal pathology practice. The majority of colorectal polyps represent precursors of either the chromosomal instability or serrated neoplasia pathways to colorectal carcinoma. Accurate reporting of these polyps has major implications for surveillance and thus for cancer prevention. In this review, we discuss the key histologic features of the major colorectal polyps with a particular emphasis on diagnostic pitfalls and areas of contention.

Characterization of sessile serrated adenomas with dysplasia including intramucosal adenocarcinoma and colorectal carcinoma with a microsatellite instability phenotype

Recent studies have shown that sessile serrated lesions (SSLs) lead to the development of colorectal cancer (CRC) with a microsatellite instability (MSI) phenotype via a dysplasia-carcinoma sequence. However, the pathological and molecular mechanisms of SSL with dysplasia (SSLD) are unclear. Here, we aimed to examine the clinicopathological and molecular alterations in SSLD and to evaluate the significance of such alterations with regard to lesion progression. Fifty-four SSLDs (20 serrated dysplasia cases and 17 intestinal dysplasia cases, including 30 low-grade dysplasia [LGD] cases, 7 high-grade dysplasia [HGD] cases, and 17 intramucosal adenocarcinomas [IMAs]) were evaluated. Molecular alterations, including immunohistochemical expression of various markers, DNA methylation status, and multiple genetic mutations (using next-generation sequencing), were assessed. Additionally, such alterations were also investigated in 41 CRCs with an MSI phenotype (invasion beyond submucosa). The frequency of mismatch repair (MMR) deficiency in SSLD was 12 of 39 cases (32.4 %), whereas the MMR proficient type was observed in 17 of 39 SSLD cases. SSLD with serrated dysplasia showed a significantly higher frequency of loss of MMR protein expression and methylation status. Moreover, loss of MMR protein expression differed significantly between LGD and IMA. Furthermore, the frequency of TP53 mutation was significantly higher in IMA than in LGD. The current findings demonstrated that SSL with serrated dysplasia may be associated with an increased risk of malignant transformation compared with intestinal dysplasia. Loss of MMR proteins and mutation of TP53 may play important roles in tumor progression from dysplasia to carcinomatous lesions.

Would initiating colorectal cancer screening from age of 45 be cost-effective in Germany? An individual-level simulation analysis

Background

Colorectal cancer (CRC) screening has been shown to be effective and cost-saving. However, the trend of rising incidence of early-onset CRC challenges the current national screening program solely for people ≥50 years in Germany, where extending the screening to those 45-49 years might be justified. This study aims to evaluate the cost-effectiveness of CRC screening strategies starting at 45 years in Germany.

Method

DECAS, an individual-level simulation model accounting for both adenoma and serrated pathways of CRC development and validated with German CRC epidemiology and screening effects, was used for the cost-effectiveness analysis. Four CRC screening strategies starting at age 45, including 10-yearly colonoscopy (COL), annual/biennial fecal immunochemical test (FIT), or the combination of the two, were compared with the current screening offer starting at age 50 years in Germany. Three adherence scenarios were considered: perfect adherence, current adherence, and high screening adherence. For each strategy, a cohort of 100,000 individuals with average CRC risk was simulated from age 20 until 90 or death. Outcomes included CRC cases averted, prevented death, quality-adjusted life-years gained (QALYG), and total incremental costs considering both CRC treatment and screening costs. A 3% discount rate was applied and costs were in 2023 Euro.

Result

Initiating 10-yearly colonoscopy-only or combined FIT + COL strategies at age 45 resulted in incremental gains of 7-28 QALYs with incremental costs of €28,360-€71,759 per 1,000 individuals, compared to the current strategy. The ICER varied from €1,029 to €9,763 per QALYG, and the additional number needed for colonoscopy ranged from 129 to 885 per 1,000 individuals. Among the alternatives, a three times colonoscopy strategy starting at 45 years of age proves to be the most effective, while the FIT-only strategy was dominated by the currently implemented strategy. The findings remained consistent across probabilistic sensitivity analyses.

Conclusion

The cost-effectiveness findings support initiating CRC screening at age 45 with either colonoscopy alone or combined with FIT, demonstrating substantial gains in quality-adjusted life-years with a modest increase in costs. Our findings emphasize the importance of implementing CRC screening 5 years earlier than the current practice to achieve more significant health and economic benefits.

Biomarker Identification through Proteomics in Colorectal Cancer

Colorectal cancer (CRC) is a devastating disease that ranks third in diagnosis and as the second leading cause of cancer-related deaths. The early detection of CRC has been shown to be the most effective strategy to improve treatment outcomes and patient survival. Therefore, current lines of research focus on the development of reliable diagnostic tools. Targeted therapies, in combination with standard chemotherapy and immune checkpoint inhibitors, have emerged as promising treatment protocols in CRC. However, their effectiveness is linked to the molecular characteristics of each patient. The importance of discovering biomarkers that help predict response to therapies and assess prognosis is evident as they allow for a fundamental step towards personalized care and successful treatments. Among the ongoing efforts to identify them, mass spectrometry-based translational proteomics presents itself as a unique opportunity as it enables the discovery and application of protein biomarkers that may revolutionize the early detection and treatment of CRC. Our objective is to show the most recent studies focused on the identification of CRC-related protein markers, as well as to provide an updated view of advances in the field of proteomics and cancer.

Clinical and endoscopic characteristics and management of 220 cases with serrated polyps

BACKGROUND

Serrated polyps are considered the precursor lesions of colorectal cancer through the serrated pathway. In the present study, we aimed to evaluate and discuss the clinical and endoscopic characteristics and management of serrated polyps.

METHODS

The data of 220 cases with serrated polyps between September 2018 and November 2021 in Shenzhen People's Hospital were retrospectively analyzed.

RESULTS

Of all these cases, 32 were hyperplastic polyps, 36 were traditional serrated adenomas, 126 were sessile serrated lesions, 25 were SSLs with dysplasia, and one was an unclassified serrated adenoma. Although most patients were males aged ≥50 years and most serrated polyps were located in the distal colon and rectum with a size of 6-10 mm and the shape of type 0-Is, there was no significant difference (P > 0.05). Serrated polyps of ≤5 mm in size and type 0-IIa were mostly removed by cold biopsy forceps. Cold snare polypectomy was primarily used for those of 6-10 mm in size. Endoscopic mucosal resection was used for those of 6-20 mm, and endoscopic submucosal dissection was used for those of ≥20 mm (P < 0.05). All complications occurred in SSL patients with or without dysplasia (P < 0.05).

CONCLUSIONS

Clinical and endoscopic characteristics were beneficial for distinguishing and diagnosing serrated polyps. In addition, management options were crucial to prevent recurrence and progression. However, the detection rate of serrated polyps was relatively low. Therefore, prospective multicenter studies with large samples are necessary to better assess colorectal serrated polyps.

The Impact of BRAF Mutation Status on Survival Outcomes and Treatment Patterns among Metastatic Colorectal Cancer Patients in Alberta, Canada

Colorectal cancer presents via multiple different clinical phenotypes that can arise from a variety of different genetic and molecular alterations. The aim of this study was to describe survival outcomes and treatment patterns of metastatic colorectal cancer (mCRC) patients by v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation status. The Alberta Cancer Registry was used to identify all patients >18 years old who had been diagnosed with mCRC in Alberta between 1 January 2017 and 31 December 2019 and had received at least one cycle of systemic therapy. Treatment patterns were compared between wild-type and mutant BRAF mCRC patients. Cox regression models and Kaplan-Meier curves were created to assess survival differences by both treatment pattern and BRAF status. A total of 488 patients were identified with mCRC, of which 42 (11.4%) were confirmed to have a BRAF mutation. The most common first-line treatment regimen was either capecitabine and oxaliplatin (CAPOX) or leucovorin calcium (folinic acid), fluorouracil, and oxaliplatin (FOLFOX). The median overall survival for mCRC patients was 20.01 months. Mutant BRAF patients had a median survival of 8.21 months compared to 20.03 months among those with wild-type BRAF. BRAF mutations among mCRC patients are associated with a considerably poor prognosis, reinforcing the need for clinical BRAF testing among newly diagnosed patients to better understand their prognosis.

Activated MKK3/MYC crosstalk impairs dabrafenib response in BRAFV600E colorectal cancer leading to resistance

Colorectal cancer (CRC) patients with BRAF mutations develop resistance to BRAF inhibitors at a very early stage. Understanding the molecular mechanisms involved in BRAF inhibitor resistance is critical for the development of novel therapeutic opportunities for this subtype of CRC patients. CRC cells bearing BRAF mutations are mostly sensitive to the abrogation of Mitogen-Activated Protein Kinase Kinase 3 (MKK3), a specific activator of p38MAPKs signaling, suggesting that BRAF alterations might addict CRC cells to the MKK3/p38MAPK signaling. Interestingly, publicly available gene expression profiling data show significantly higher MKK3 transcript levels in CRC lines with acquired resistance to BRAF inhibitors. Herein, we investigated the roles of MKK3 in the response to BRAF targeting (dabrafenib) with COLO205 and HT29 BRAFV600E CRC lines and derived dabrafenib-resistant (DABR) sublines. Dabrafenib treatments reduce MKK3 activation by inducing autophagy in parental but not DABR cells. The MKK3 knockdown induces cell death in DABR cells, whereas ectopic MKK3 expression reduces dabrafenib sensitivity in parental cells. Mechanistically, activated MKK3 interacts and co-localizes with c-Myc oncoprotein (MYC), sustaining MYC protein stability and thus preventing the dabrafenib induced effects in CRC DABR cells both in vitro and in vivo. Overall, we identify a novel molecular mechanism beyond the dabrafenib resistance, shedding light on an uncovered vulnerability for the development of novel therapeutic opportunities in BRAFV600E CRC.

Consensus molecular subtype transition during progression of colorectal cancer

The consensus molecular subtype (CMS) classification divides colorectal cancer (CRC) into four distinct subtypes based on RNA expression profiles. The biological differences between CMSs are already present in CRC precursor lesions, but not all CMSs pose the same risk of malignant transformation. To fully understand the path to malignant transformation and to determine whether CMS is a fixed entity during progression, genomic and transcriptomic data from two regions of the same CRC lesion were compared: the precursor region and the carcinoma region. In total, 24 patients who underwent endoscopic removal of T1-2 CRC were included. Regions were subtyped for CMS and DNA mutation analysis was performed. Additionally, a set of 85 benign adenomas was CMS-subtyped. This analysis revealed that almost all benign adenomas were classified as CMS3 (91.8%). In contrast, CMS2 was the most prevalent subtype in precursor regions (66.7%), followed by CMS3 (29.2%). CMS4 was absent in precursor lesions and originated at the carcinoma stage. Importantly, CMS switching occurred in a substantial number of cases and almost all (six out of seven) CMS3 precursor regions showed a shift to a different subtype in the carcinoma part of the lesion, which in four cases was classified as CMS4. In conclusion, our data indicate that CMS3 is related to a more indolent type of precursor lesion that less likely progresses to CRC and when this occurs, it is often associated with a subtype change that includes the more aggressive mesenchymal CMS4. In contrast, an acquired CMS2 signature appeared to be rather fixed during early CRC development. Combined, our data show that subtype changes occur during progression and that CMS3 switching is related to changes in the genomic background through acquisition of a novel driver mutation (TP53) or selective expansion of a clone, but also occurred independently of such genetic changes. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Methylated DNA Markers for Sporadic Colorectal and Endometrial Cancer Are Strongly Associated with Lynch Syndrome Cancers

Lynch syndrome (LS) markedly increases risks of colorectal and endometrial cancers. Early detection biomarkers for LS cancers could reduce the needs for invasive screening and surgical prophylaxis.To validate a panel of methylated DNA markers (MDM) previously identified in sporadic colorectal cancer and endometrial cancer for discrimination of these cancers in LS.In a case-control design, previously identified MDMs for the detection of colorectal cancer and endometrial cancer were assayed by qMSP on tissue-extracted DNA. Results were normalized to ACTB values within each sample. Least absolute shrinkage and selection operator models to classify colorectal cancer and endometrial cancer were trained on sporadic cases and controls and then applied to classify colorectal cancer and endometrial cancer, in those with LS, and cross-validated.We identified colorectal cancer cases (23 with LS, 48 sporadic), colorectal controls (32 LS, 48 sporadic), endometrial cancer cases (30 LS, 48 sporadic), and endometrial controls (29 LS, 37 sporadic). A 3-MDM panel (LASS4, LRRC4, and PPP2R5C) classified LS-CRC from LS controls with an AUC of 0.92 (0.84-0.99); results were similar for sporadic colorectal cancer. A 6-MDM panel (SFMBT2, MPZ, CYTH2, DIDO1, chr10.4479, and EMX2OS) discriminated LS-EC from LS controls with an AUC of 0.92 (0.83-1.0); the AUC for sporadic endometrial cancer versus sporadic controls was nominally higher, 0.99 (0.96-1.0).MDMs previously identified in sporadic endometrial cancer and colorectal cancer discriminate between endometrial cancer and benign endometrium and colorectal cancer and benign colorectum in LS. This supports the inclusion of patients with LS within future prospective clinical trials evaluating endometrial cancer and colorectal cancer MDMs and may provide a new avenue for cancer screening or surveillance in this high-risk population.

PREVENTION RELEVANCE

Lynch syndrome (LS) markedly increases risks of colorectal and endometrial cancers. Early detection biomarkers for LS cancers could reduce the needs for invasive screening and surgery. Methylated DNA markers previously identified in sporadic endometrial cancer and colorectal cancer discriminate between benign and cancer tissue in LS.

Recent progress of targeted nanocarriers in diagnostic, therapeutic, and theranostic applications in colorectal cancer

Cancer at the lower end of the digestive tract, colorectal cancer (CRC), starts with asymptomatic polyps, which can be diagnosed as cancer at a later stage. It is the fourth leading cause of malignancy-associated mortality worldwide. Despite progress in conventional treatment strategies, the possibility to overcome the mortality and morbidity issues with the enhancement of the lifespan of CRC patients is limited. With the advent of nanocarrier-based drug delivery systems, a promising revolution has been made in diagnosis, treatment, and theranostic purposes for cancer management. Herein, we reviewed the progress of miniaturized nanocarriers, such as liposomes, niosomes, solid lipid nanoparticles, micelles, and polymeric nanoparticles, employed in passive and active targeting and their role in theranostic applications in CRC. With this novel scope, the diagnosis and treatment of CRC have proceeded to the forefront of innovation, where specific characteristics of the nanocarriers, such as processability, flexibility in developing precise architecture, improved circulation, site-specific delivery, and rapid response, facilitate the management of cancer patients. Furthermore, surface-engineered technologies for the nanocarriers could involve receptor-mediated deliveries towards the overexpressed receptors on the CRC microenvironment. Moreover, the potential of clinical translation of these targeted miniaturized formulations as well as the possible limitations and barriers that could impact this translation into clinical practice were highlighted. The advancement of these newest developments in clinical research and progress into the commercialization stage gives hope for a better tomorrow.

Clusterin Expression in Colorectal Carcinomas

Colorectal cancer is the third most diagnosed cancer, behind only breast and lung cancer. In terms of overall mortality, it ranks second due to, among other factors, problems with screening programs, which means that one of the factors that directly impacts survival and treatment success is early detection of the disease. Clusterin (CLU) is a molecular chaperone that has been linked to tumorigenesis, cancer progression and resistance to anticancer treatments, which has made it a promising drug target. However, it is still necessary to continue this line of research and to adjust the situations in which its use is more favorable. The aim of this paper is to review the current genetic knowledge on the role of CLU in tumorigenesis and cancer progression in general, and discuss its possible use as a therapeutic target in colorectal cancer.

Preliminary exploration of the effects of environmental factors on the microsatellite status of BRAF-mutated colorectal cancer

BACKGROUND

To investigate the expression of EBV products and frequency of gallstone disease (GD) among different microsatellite status in colorectal cancer (CRC) with BRAFV600E mutation.

METHODS

We collected 30 CRC patients with BRAFV600E mutation and 10 BRAF ( -) CRC patients as well as 54 healthy subjects. Tumor tissue samples were collected to detect the mutation of BRAF, KRAS, and TP53. Microsatellite status was determined by immunohistochemistry and PCR. EBER in situ hybridization was performed to detect EBV. In addition, we also collected clinical information about the patients.

RESULTS

We found that although EBV products were detected in CRC, there were no significant differences in the EBV distribution between the different BRAF groups. Our study demonstrated that BRAFV600E mutation and BRAFV600E with MSI were significantly more frequent in the right CRC. Furthermore, the KRAS mutation rate in the BRAF-wild-type group was proved to be significantly higher than that in the BRAF mutation group. In addition, we revealed that BRAF mutation and MSI were independent risk factors of TNM stage. The frequency of GD was higher in CRC patients than in general population, and although there was no significant difference between CRC with or without BRAFV600E mutation, the highest frequency of GD was found in MSS CRC with BRAFV600E mutation.

CONCLUSIONS

EBV plays a role in CRC, but is not a determinant of different microsatellite status in CRC with BRAFV600E mutation. The frequency of GD in MSS CRC with BRAFV600E mutation is significantly higher than that in the general population.

Advances in Mapping Tumor Progression from Precancer Atlases

Tissue profiling technologies present opportunities for understanding transition from precancerous lesions to malignancy, which may impact risk stratification, prevention, and even cancer treatment. A human precancer atlas building effort is ongoing to tackle the significant challenge of decoding the heterogeneity among cells, specimens, and patients. Here, we discuss the findings resulting from atlases built across precancer types, including those found in colon, breast, lung, stomach, cervix, and skin, using bulk, single-cell, and spatial profiling strategies. We highlight two main themes that emerge across precancer types: the ordering of molecular events that occur during tumor progression and the fluctuation of microenvironmental response during precancer progression. We further highlight the key challenges of data integration across large cohorts of patients, and the need for computational tools to reliably annotate and quality control high-volume, high-dimensional data.

Sessile serrated lesions with dysplasia: is it possible to nip them in the bud?

The serrated neoplasia pathway constitutes an "alternative route" to colorectal cancer (CRC), and sessile serrated lesions with dysplasia (SSLDs) are an intermediate step between sessile serrated lesions (SSLs) and invasive CRC in this pathway. While SSLs show indolent growth before becoming dysplastic (> 10-15 years), SSLDs are considered to rapidly progress to either immunogenic microsatellite instable-high (MSI-H) CRC (presumably 75% of cases) or mesenchymal microsatellite stable (MSS) CRC. Their flat shapes and the relatively short window of this intermediate state make it difficult to detect and diagnose SSLDs; thus, these lesions are potent precursors of post-colonoscopy/interval cancers. Confusing terminology and the lack of longitudinal observation data of serrated polyps have hampered the accumulation of knowledge about SSLDs; however, a growing body of evidence has started to clarify their characteristics and biology. Together with recent efforts to incorporate terminology, histological studies of SSLDs have identified distinct dysplastic patterns and revealed alterations in the tumor microenvironment (TME). Molecular studies at the single-cell level have identified distinct gene alterations in both the epithelium and the TME. Mouse serrated tumor models have demonstrated the importance of TME in disease progression. Advances in colonoscopy provide clues to distinguish pre-malignant from non-malignant-SSLs. Recent progress in all aspects of the field has enhanced our understanding of the biology of SSLDs. The aim of this review article was to assess the current knowledge of SSLDs and highlight their clinical implications.

Robotic Colonoscopy and Beyond: Insights into Modern Lower Gastrointestinal Endoscopy

Lower gastrointestinal endoscopy is considered the gold standard for the diagnosis and removal of colonic polyps. Delays in colonoscopy following a positive fecal immunochemical test increase the likelihood of advanced adenomas and colorectal cancer (CRC) occurrence. However, patients may refuse to undergo conventional colonoscopy (CC) due to fear of possible risks and pain or discomfort. In this regard, patients undergoing CC frequently require sedation to better tolerate the procedure, increasing the risk of deep sedation or other complications related to sedation. Accordingly, the use of CC as a first-line screening strategy for CRC is hampered by patients' reluctance due to its invasiveness and anxiety about possible discomfort. To overcome the limitations of CC and improve patients' compliance, several studies have investigated the use of robotic colonoscopy (RC) both in experimental models and in vivo. Self-propelling robotic colonoscopes have proven to be promising thanks to their peculiar dexterity and adaptability to the shape of the lower gastrointestinal tract, allowing a virtually painless examination of the colon. In some instances, when alternatives to CC and RC are required, barium enema (BE), computed tomographic colonography (CTC), and colon capsule endoscopy (CCE) may be options. However, BE and CTC are limited by the need for subsequent investigations whenever suspicious lesions are found. In this narrative review, we discussed the current clinical applications of RC, CTC, and CCE, as well as the advantages and disadvantages of different endoscopic procedures, with a particular focus on RC.

A Multi-Omics Overview of Colorectal Cancer to Address Mechanisms of Disease, Metastasis, Patient Disparities and Outcomes

Human colorectal cancer (CRC) is one of the most common malignancies in men and women across the globe, albeit CRC incidence and mortality shows a substantial racial and ethnic disparity, with the highest burden in African American patients. Even with effective screening tools such as colonoscopy and diagnostic detection assays, CRC remains a substantial health burden. In addition, primary tumors located in the proximal (right) or distal (left) sides of the colorectum have been shown to be unique tumor types that require unique treatment schema. Distal metastases in the liver and other organ systems are the major causes of mortality in CRC patients. Characterizing genomic, epigenomic, transcriptomic and proteomic (multi-omics) alterations has led to a better understanding of primary tumor biology, resulting in targeted therapeutic advancements. In this regard, molecular-based CRC subgroups have been developed that show correlations with patient outcomes. Molecular characterization of CRC metastases has highlighted similarities and differences between metastases and primary tumors; however, our understanding as to how to improve patient outcomes based on metastasis biology is lagging and remains a major obstacle to improving CRC patient outcomes. In this review, we will summarize the multi-omics features of primary CRC tumors and their metastases across racial and ethnic groups, the differences in proximal and distal tumor biology, molecular-based CRC subgroups, treatment strategies and challenges for improving patient outcomes.

Short interfering RNA in colorectal cancer: is it wise to shoot the messenger?

Colorectal cancer (CRC) is the third most common cancer and the leading cause of gastrointestinal cancer death. 90% of people diagnosed with colorectal cancer are over the age of 50; nevertheless, the illness is more aggressive among those detected at a younger age. Chemotherapy-based treatment has several adverse effects on both normal and malignant cells. The primary signaling pathways implicated in the advancement of CRC include hedgehog (Hh), janus kinase and signal transducer and activator of transcription (JAK/STAT), Wingless-related integration site (Wnt)/β-catenin, transforming growth factor-β (TNF-β), epidermal growth factor receptor (EGFR)/Mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K), nuclear factor kappa B (NF-κB), and Notch. Loss of heterozygosity in tumor suppressor genes like adenomatous polyposis coli, as well as mutation or deletion of genes like p53 and Kirsten rat sarcoma viral oncogene (KRAS), are all responsible for the occurrence of CRC. Novel therapeutic targets linked to these signal-transduction cascades have been identified as a consequence of advances in small interfering RNA (siRNA) treatments. This study focuses on many innovative siRNA therapies and methodologies for delivering siRNA therapeutics to the malignant site safely and effectively for the treatment of CRC. Treatment of CRC using siRNA-associated nanoparticles (NPs) may inhibit the activity of oncogenes and MDR-related genes by targeting a range of signaling mechanisms. This study summarizes several siRNAs targeting signaling molecules, as well as the therapeutic approaches that might be employed to treat CRC in the future.

Emerging Tests for Noninvasive Colorectal Cancer Screening

Colorectal cancer (CRC) is among the most common cancers globally and a major cause of cancer-related deaths. The American Cancer Society estimates that CRC will kill 1 in 60 Americans, and CRC screening is recommended for all Americans ≥45 years of age. Current CRC screening methods are effective for preventing CRC and have been shown to reduce CRC-related mortality. However, none of the currently available tests is ideal, and many people are not compliant with screening recommendations. Novel screening tests based on advances in CRC molecular biology, genetics, and epigenetics, combined with developments in sequencing technologies and computational analytic methods, have been developed to address the shortcomings of current CRC screening tests. These emerging tests include blood-based assays that use plasma-derived circulating tumor DNA and serum proteins to detect early CRC and advanced adenomas, assays that use stool DNA or mRNA, and methods for profiling the gut microbiome. Here we review current screening modalities, and we discuss the principles behind the most promising emerging CRC screening tests and the data supporting their potential to be used in clinical practice.

Serrated polyps in patients with ulcerative colitis: Unique clinicopathological and biological characteristics

BACKGROUND

Serrated polyps have recently been reported in patients with ulcerative colitis (UC); however, their prevalence and detailed characteristics remain unclear.

METHODS

The prevalence and clinicopathological and biological characteristics of serrated polyps in patients with UC were retrospectively examined in a single tertiary inflammatory bowel disease center in Japan from 2000 to 2020.

RESULTS

Among 2035 patients with UC who underwent total colonoscopy, 252 neoplasms, including 36 serrated polyps (26 in colitis-affected segments, 10 in colitis-unaffected segments), were identified in 187 patients with UC. The proportion of serrated polyps was 1.8% (36/2035). Serrated polyps in colitis-affected segments were common with extensive colitis (88%), history of persistent active colitis (58%), and long UC duration (12.1 years). Serrated polyps in colitis-affected segments were more common in men (88%). Of the 26 serrated polyps in colitis-affected segments, 15, 6, and 5 were categorized as sessile serrated lesion-like dysplasia, traditional serrated adenoma-like dysplasia, and serrated dysplasia not otherwise specified, respectively. Sessile serrated lesion-like dysplasia was common in the proximal colon (67%) and with BRAF mutation (62%), whereas traditional serrated adenoma-like dysplasia and serrated dysplasia not otherwise specified were common in the distal colon (100% and 80%, respectively) and with KRAS mutations (100% and 75%, respectively).

CONCLUSIONS

Serrated polyps comprised 14% of the neoplasias in patients with UC. Serrated polyps in colitis-affected segments were common in men with extensive and longstanding colitis, suggesting chronic inflammation in the development of serrated polyps in patients with UC.

MIST: multiple instance learning network based on Swin Transformer for whole slide image classification of colorectal adenomas

Colorectal adenoma is a recognized precancerous lesion of colorectal cancer (CRC), and at least 80% of colorectal cancers are malignantly transformed from it. Therefore, it is essential to distinguish benign from malignant adenomas in the early screening of colorectal cancer. Many deep learning computational pathology studies based on whole slide images (WSIs) have been proposed. Most approaches require manual annotation of lesion regions on WSIs, which is time-consuming and labor-intensive. This study proposes a new approach, MIST - Multiple Instance learning network based on the Swin Transformer, which can accurately classify colorectal adenoma WSIs only with slide-level labels. MIST uses the Swin Transformer as the backbone to extract features of images through self-supervised contrastive learning and uses a dual-stream multiple instance learning network to predict the class of slides. We trained and validated MIST on 666 WSIs collected from 480 colorectal adenoma patients in the Department of Pathology, The Affiliated Drum Tower Hospital of Nanjing University Medical School. These slides contained six common types of colorectal adenomas. The accuracy of external validation on 273 newly collected WSIs from Nanjing First Hospital was 0.784, which was superior to the existing methods and reached a level comparable to that of the local pathologist's accuracy of 0.806. Finally, we analyzed the interpretability of MIST and observed that the lesion areas of interest in MIST were generally consistent with those of interest to local pathologists. In conclusion, MIST is a low-burden, interpretable, and effective approach that can be used in colorectal cancer screening and may lead to a potential reduction in the mortality of CRC patients by assisting clinicians in the decision-making process. © 2022 The Pathological Society of Great Britain and Ireland.

Sessile serrated lesion detection rates continue to increase: 2008-2020

Background and study aims  We assessed sessile serrated lesion detection rate (SSLDR) at a large academic medical center from 2008 to 2020 and modeled a local, aspirational target SSLDR. We also assessed SSLDRs among all gastroenterology fellows to better understand the relationship between SSLDRs and total colonoscopies performed. Patients and methods  SSL-positive pathology results were flagged from a dataset composed of all screening colonoscopies for average-risk patients from 2008 to 2020. Unadjusted SSLDRs were calculated for individual endoscopists by year. A mixed effects logistic regression was used to estimate the log odds of SSL detection, with one model estimating division-wide predictors of SSL detection and a second model focused exclusively on colonoscopies performed by fellows. Model-adjusted SSLDRs were estimated for all 13 years and across both categories of all endoscopists and fellows only. Results  Adjusted SSLDRs showed a consistent improvement in SSLDR from a low of 0.37 % (95 % confidence interval [CI]: 0.10-0.63) in 2008 to a high of 7.94 % (95 % CI: 6.34-9.54) in 2020. Among fellows only, the odds of SSL detection were significantly lower during their first year compared to their second year (OR: 0.80, 95 % CI: 0.66-0.98) but not significantly higher in their third year compared to their second year (OR: 1.09, 95 % CI: 0.85-1.4). Conclusions  SSLDR increased steadily and significantly throughout our study period but variance among endoscopists persists. The peak SSLDR from 2020 of 7.94 % should serve as the local aspirational target for this division's attendings and fellows but should be continuously reevaluated.

Modeling the Natural History and Screening Effects of Colorectal Cancer Using Both Adenoma and Serrated Neoplasia Pathways: The Development, Calibration, and Validation of a Discrete Event Simulation Model

Background. Existing colorectal cancer (CRC) screening models mostly focus on the adenoma pathway of CRC development, overlooking the serrated neoplasia pathway, which might result in overly optimistic screening predictions. In addition, Bayesian inference methods have not been widely used for model calibration. We aimed to develop a CRC screening model accounting for both pathways, calibrate it with approximate Bayesian computation (ABC) methods, and validate it with large CRC screening trials. Methods. A discrete event simulation (DES) of the CRC natural history (DECAS) was constructed using the adenoma and serrated pathways in R software. The model simulates CRC-related events in a specific birth cohort through various natural history states. Calibration took advantage of 74 prevalence data points from the German screening colonoscopy program of 5.2 million average-risk participants using an ABC method. CRC incidence outputs from DECAS were validated with the German national cancer registry data; screening effects were validated using 17-y data from the UK Flexible Sigmoidoscopy Screening sigmoidoscopy trial and a German screening colonoscopy cohort study. Results. The Bayesian calibration rendered 1,000 sets of posterior parameter samples. With the calibrated parameters, the observed age- and sex-specific CRC prevalences from the German registries were within the 95% DECAS-predicted intervals. Regarding screening effects, DECAS predicted a 41% (95% intervals 30%-51%) and 62% (95% intervals 55%-68%) reduction in 17-y cumulative CRC mortality for a single screening sigmoidoscopy and colonoscopy, respectively, falling within 95% confidence intervals reported in the 2 clinical studies used for validation. Conclusions. We presented DECAS, the first Bayesian-calibrated DES model for CRC natural history and screening, accounting for 2 CRC tumorigenesis pathways. The validated model can serve as a valid tool to evaluate the (cost-)effectiveness of CRC screening strategies.

Highlights

This article presents a new discrete event simulation model, DECAS, which models both adenoma-carcinoma and serrated neoplasia pathways for colorectal cancer (CRC) development and CRC screening effects.DECAS is calibrated based on a Bayesian inference method using the data from German screening colonoscopy program, which consists of more than 5 million first-time average-risk participants aged 55 years and older in 2003 to 2014.DECAS is flexible for evaluating various CRC screening strategies and can differentiate screening effects in different parts of the colon.DECAS is validated with large screening sigmoidoscopy and colonoscopy clinical study data and can be further used to evaluate the (cost-)effectiveness of German colorectal cancer screening strategies.

Small bowel intussusception caused by a serrated adenoma: a case report

The case was a 17-year-old young woman with a one-year history of recurrent abdominal pain and discomfort. B-scan ultrasonography identified intussusception and contrast-enhanced computed tomography of the pelvis revealed volvulus. A laparoscopic procedure was planned to identify the reason for the intussusception and obstruction. Intraoperatively, the intussusception was found to be caused by a cauliflower-shaped polypoid tumor measuring approximately 4 × 3 cm. Postoperative pathological examination identified the tumor to be a traditional serrated adenoma of the small intestine, which is rare and has atypical clinical manifestations. If unexplained abdominal pain or gastrointestinal bleeding occurs and an abdominal mass cannot be accurately located, laparoscopic or open surgery should be performed immediately. Early surgery is the most effective and reliable way of securing a prompt diagnosis and a favorable prognosis.

Transcriptome of sessile serrated adenoma/polyps is associated with MSI-high colorectal cancer and decreased expression of CDX2

The objective of this study was to elucidate the molecular background of sessile serrated adenoma/polyp (SSA/P) endoscopically resected with comprehensive gene expression analysis. Gene expression profiling was performed for 10 tumor-normal pairs of SSA/P. Cluster analysis, gene set enrichment analysis (GSEA), and consensus molecular subtype (CMS) classification of colorectal cancer (CRC) were applied to our transcriptome analysis. Unsupervised cluster analysis showed that the gene expression profile of SSA/Ps is different from that of adjacent normal epithelial cells, even in the very early stage of tumorigenesis. According to the CMS classification, our microarray data indicated that SSA/Ps were classified as CMS1. GSEA demonstrated a strong association between SSA/P and microsatellite instability-high (MSI-H) CRC (p < 10^-5 ). Transcriptome analysis of five MSI-related genes (MSH2, MSH6, MLH1, PMS1, and PMS2) and five CRC-related genes (BRAF, KRAS, APC, TP53, and CDX2) showed that CDX2 expression was most severely decreased in SSA/P. Immunohistochemical staining confirmed that CDX2 protein was reduced compared with the surrounding mucosa. Direct sequencing of the BRAF gene showed that the BRAF V600E mutation was detected in only nine of 36 cases. In a mouse model, BRAF, APC, or CDX2 deficiency indicated that the gene expression pattern with loss of CDX2 is more similar to our SSA/Ps compared with those induced by BRAF or APC mutation. Transcriptome analysis of SSA/Ps showed characteristic gene expression with a strong resemblance to MSI-H CRC. Downregulation of CDX2 expression is an essential molecular mechanism involved in the initial stage of SSA/P tumorigenesis. (UMIN000027365).

Body Mass Index, sex, non-steroidal anti-inflammatory drug medications, smoking and alcohol are differentially associated with World Health Organisation criteria and colorectal cancer risk in people with Serrated Polyposis Syndrome: an Australian case-control study

OBJECTIVE

The unknown aetiology of Serrated Polyposis Syndrome (SPS) impedes risk prediction and prevention. We investigated risk factors for SPS, overall and stratified by World Health Organization (WHO)²⁰¹⁰ clinical criteria and by colorectal cancer (CRC).

METHOD

A retrospective case-control study involving a cross-sectional analysis from 350 unrelated individuals with SPS from the Genetics of Colonic Polyposis Study and 714 controls from the Australasian Colorectal Cancer Family Registry. Univariate and multivariate logistic regression modelling was used to determine the association between risk factors and SPS and risk factors associated with CRC in SPS.

RESULTS

Female biological sex (odds ratio (OR) = 4.54; 95%Confidence interval (CI) = 2.77-7.45), increasing body mass index (BMI) at age 20 years (OR = 1.09; 95%CI = 1.04-1.13), hormone replacement therapy (OR = 0.44; 95%CI = 0.20.98), and increasing weekly folate intake (OR = 0.82; 95%CI = 0.75-0.90) were associated with SPS by multivariate analysis. Increasing weekly calcium intake (OR = 0.79; 95%CI = 0.64-0.97) and smoking > 10 cigarettes daily (OR = 0.45; 95%CI = 0.23-0.86) were associated with WHO criterion I only. The consumption of 1-100 g of alcohol per week (OR = 0.39; 95%CI = 0.18-0.83) was associated with WHO criterion III only. Smoking 1-5 cigarettes daily (OR = 2.35; 95%CI = 1.09-5.05), weekly non-steroidal anti-inflammatory drug (NSAIDs) intake (OR = 0.88; 95%CI = 0.78-0.99), and increased height (OR = 1.09; 95% = 1.05-1.13), were associated with SPS fulfilling both WHO criteria I and III. Moreover, weekly NSAIDs intake (OR = 0.81; 95%CI = 0.67-0.98) was associated with a reduced likelihood of CRC in SPS.

CONCLUSION

We identified novel risk and potential protective factors associated with SPS, some specific for certain WHO²⁰¹⁰ criteria. Weekly use of NSAIDs may reduce the risk of CRC in people with SPS.

Linked color imaging improves visibility of colorectal serrated lesion by high color contrast to surrounding mucosa

OBJECTIVES

This study aimed to objectively evaluate the efficacy of linked color imaging (LCI) in diagnosing colorectal serrated lesions by utilizing visibility scores and color differences.

METHODS

We examined 89 serrated lesions, including 36 hyperplastic polyps (HPs), 47 sessile serrated lesions (SSLs), and six traditional serrated adenomas (TSAs). Visibility changes were scored by six endoscopists as follows: 4, excellent; 3, good; 2, fair; and 1, poor. Furthermore, images obtained by white-light imaging (WLI) or LCI were assessed using the CIELAB color space in the lesion and adjacent mucosa. We calculated the mean color values (L*, a*, and b*) measured at five regions of interest of the sample lesion and surrounding mucosa and derived the color difference (ΔE*).

RESULTS

The visibility scores of both HPs and SSLs in LCI were significantly higher than that in WLI (HPs, 3.67/2.89, P < 0.001; SSLs, 3.07/2.36, P < 0.001). Furthermore, SSLs showed a significantly higher L* value and significantly lower a* and b* values in LCI than the adjacent mucosae (L*, 61.76/58.23, P = 0.016; a*, 14.91/17.58, P = 0.019; b*, 20.42/24.21, P = 0.007), while WLI produced no significant difference in any color value. A similar trend was apparent in HPs. In all serrated groups, LCI revealed significantly greater ΔE* values between the lesion and adjacent mucosa than WLI (HPs, 11.54/6.12; SSLs, 13.43/7.67; TSAs, 35.00/22.48).

CONCLUSION

Linked color imaging showed higher color contrast between serrated lesions and the surrounding mucosae compared with WLI, indicating improved visibility of colorectal serrated lesion using LCI.

Efficacy and safety of cold snare polypectomy for sessile serrated polyps ≥ 10 mm: A systematic review and meta-analysis

BACKGROUND

Cold snare polypectomy (CSP) is a promising technique for the removal of sessile serrated polyps (SSPs) ≥ 10 mm. However, the efficacy and safety of this technique remain undetermined.

AIMS

We aimed to comprehensively evaluate the efficacy and safety of CSP for SSPs ≥ 10 mm.

METHODS

PubMed, EMBASE, Web of Science and Cochrane Library were searched up to January 2021.

RESULTS

A total of 10 studies consisting of 1727 SSPs (range, 10-40 mm) from 1021 patients were included. The overall rates of technical success, adverse events (AEs) and residual SSPs were 100%, 0.7% and 2.9%, respectively. Subgroup analysis showed that the rates of technical success and AEs were comparable between CSP and cold endoscopic mucosal resection (EMR) (99.9% vs. 100% and 1.3% vs. 0.5%, respectively), between the proximal and distal colon (100% vs. 99.9% and 0.3% vs. 0, respectively), and between polyps of 10-19 mm and ≥20 mm (99.8% vs. 100% and 0.9% vs. 0, respectively). However, subgroup analysis showed that the rate of residual SSPs was slightly lower in CSP compared with cold EMR (1.3% vs. 3.9%), as well as in polyps of 10-19 mm compared with those ≥20 mm (3.1% vs. 4.7%).

CONCLUSION

CSP was an effective and safe technique for removing SSPs ≥ 10 mm.

Single-cell Transcriptomics Reveals Early Molecular and Immune Alterations Underlying the Serrated Neoplasia Pathway Toward Colorectal Cancer

BACKGROUND & AIMS

Approximately one-third of colorectal cancers develop from serrated lesions (SLs), including hyperplastic polyp (HP), sessile serrated lesion (SSL), traditional serrated adenoma (TSA), and SSL with dysplasia (SSLD) through the serrated neoplasia pathway, which progresses faster than the conventional adenoma-carcinoma pathway. We sought to depict the currently unclarified molecular and immune alterations by the single-cell landscape in SLs.

METHODS

We performed single-cell RNA sequencing of 16 SLs (including 4 proximal HPs, 5 SSLs, 2 SSLDs, and 5 TSAs) vs 3 normal colonic tissues.

RESULTS

A total of 60,568 high-quality cells were obtained. Two distinct epithelial clusters with redox imbalance in SLs were observed, along with upregulation of tumor-promoting SerpinB6 that regulated ROS level. Epithelial clusters of SSL and TSA showed distinct molecular features: SSL-specific epithelium manifested overexpressed proliferative markers with Notch pathway activation, whereas TSA-specific epithelium showed Paneth cell metaplasia with aberrant lysozyme expression. As for immune contexture, enhanced cytotoxic activity of CD8⁺ T cells was observed in SLs; it was mainly attributable to increased proportion of CD103⁺CD8⁺ tissue-resident memory T cells, which might be regulated by retinoic acid metabolism. Microenvironment of SLs was generally immune-activated, whereas some immunosuppressive cells (regulatory T cells, anti-inflammatory macrophages, MDK⁺IgA⁺ plasma cells, MMP11-secreting PDGFRA⁺ fibroblasts) also emerged at early stage and further accumulated in SSLD.

CONCLUSION

Epithelial, immune, and stromal components in the serrated pathway undergo fundamental alterations. Future molecular subtypes of SLs and potential immune therapy might be developed.

Trial protocol for COLO-DETECT: A randomized controlled trial of lesion detection comparing colonoscopy assisted by the GI Genius™ artificial intelligence endoscopy module with standard colonoscopy

AIM

Colorectal cancer is the second commonest cause of cancer death worldwide. Colonoscopy plays a key role in the control of colorectal cancer and, in that regard, maximizing detection (and removal) of pre-cancerous adenomas at colonoscopy is imperative. GI Genius™ (Medtronic Ltd) is a computer-aided detection system that integrates with existing endoscopy systems and improves adenoma detection during colonoscopy. COLO-DETECT aims to assess the clinical and cost effectiveness of GI Genius™ in UK routine colonoscopy practice.

METHODS AND ANALYSIS

Participants will be recruited from patients attending for colonoscopy at National Health Service sites in England, for clinical symptoms, surveillance or within the national Bowel Cancer Screening Programme. Randomization will involve a 1:1 allocation ratio (GI Genius™-assisted colonoscopy:standard colonoscopy) and will be stratified by age category (<60 years, 60-<74 years, ≥74 years), sex, hospital site and indication for colonoscopy. Demographic data, procedural data, histology and post-procedure patient experience and quality of life will be recorded. COLO-DETECT is designed and powered to detect clinically meaningful differences in mean adenomas per procedure and adenoma detection rate between GI Genius™-assisted colonoscopy and standard colonoscopy groups. The study will close when 1828 participants have had a complete colonoscopy. An economic evaluation will be conducted from the perspective of the National Health Service. A patient and public representative is contributing to all stages of the trial. Registered at ClinicalTrials.gov (NCT04723758) and ISRCTN (10451355). WHAT WILL THIS TRIAL ADD TO THE LITERATURE?: COLO-DETECT will be the first multi-centre randomized controlled trial evaluating GI Genius™ in real world colonoscopy practice and will, uniquely, evaluate both clinical and cost effectiveness.

Advances in the management of peritoneal malignancies

Peritoneal surface malignancies (PSMs) are usually associated with a poor prognosis. Nonetheless, in line with advances in the management of most abdominopelvic metastatic diseases, considerable progress has been made over the past decade. An improved understanding of disease biology has led to the more accurate prediction of neoplasia aggressiveness and the treatment response and has been reflected in the proposal of new classification systems. Achieving complete cytoreductive surgery remains the cornerstone of curative-intent treatment of PSMs. Alongside centralization in expert centres, enabling the delivery of multimodal and multidisciplinary strategies, preoperative management is a crucial step in order to select patients who are most likely to benefit from surgery. Depending on the specific PSM, the role of intraperitoneal chemotherapy and of perioperative systemic chemotherapy, in particular, in the neoadjuvant setting, is established in certain scenarios but questioned in several others, although more prospective data are required. In this Review, we describe advances in all aspects of the management of PSMs including disease biology, assessment and improvement of disease resectability, perioperative management, systemic therapy and pre-emptive management, and we speculate on future research directions.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

The Insulin-like Growth Factor System and Colorectal Cancer

Insulin-like growth factors (IGFs) are peptides which exert mitogenic, endocrine and cytokine activities. Together with their receptors, binding proteins and associated molecules, they participate in numerous pathophysiological processes, including cancer development. Colorectal cancer (CRC) is a disease with high incidence and mortality rates worldwide, whose etiology usually represents a combination of the environmental and genetic factors. IGFs are most often increased in CRC, enabling excessive autocrine/paracrine stimulation of the cell growth. Overexpression or increased activation/accessibility of IGF receptors is a coinciding step which transmits IGF-related signals. A number of molecules and biochemical mechanisms exert modulatory effects shaping the final outcome of the IGF-stimulated processes, frequently leading to neoplastic transformation in the case of irreparable disbalance. The IGF system and related molecules and pathways which participate in the development of CRC are the focus of this review.

Mechanisms and prospects of circular RNAs and their interacting signaling pathways in colorectal cancer

Colorectal cancer (CRC) is the leading malignant tumor in terms of morbidity and mortality worldwide, and its pathogenesis involves multiple factors, including environment, lifestyle, and genetics. Continuing evidence suggests that circular RNAs (circRNAs), as a novel non-coding RNA, constitute an important genetic variable in the pathogenesis of CRC. These circRNAs with covalently closed-loop structures exist objectively in organisms. They not only have the biological functions of regulating the expression of target genes, changing the activity of proteins, and translating proteins, but also play a key role in the proliferation, invasion, migration, and apoptosis of tumor cells. CRC is one of the most common cancers in which circRNAs are involved in tumorigenesis, metastasis, and drug resistance, and circRNAs have been demonstrated to function through crosstalk with multiple signaling pathways. Therefore, this review summarizes the biological and carcinogenic functions of circRNAs and their related PI3K/AKT, MAPK, Notch, JAK/STAT, Hippo/YAP, WNT/β-catenin, and VEGF signaling pathways in CRC. We further explore the clinical value of circRNAs and important signaling proteins in the diagnosis, prognosis, and treatment of CRC.

Computer-aided diagnosis of serrated colorectal lesions using non-magnified white-light endoscopic images

PURPOSE

Computer-aided diagnosis systems for polyp characterization are commercially available but cannot recognize subtypes of sessile lesions. This study aimed to develop a computer-aided diagnosis system to characterize polyps using non-magnified white-light endoscopic images.

METHODS

A total of 2249 non-magnified white-light images from 1030 lesions including 534 tubular adenomas, 225 sessile serrated adenoma/polyps, and 271 hyperplastic polyps in the proximal colon were consecutively extracted from an image library and divided into training and testing datasets (4:1), based on the date of colonoscopy. Using ResNet-50 networks, we developed a classifier (1) to differentiate adenomas from serrated lesions, and another classifier (2) to differentiate sessile serrated adenoma/polyps from hyperplastic polyps. Diagnostic performance was assessed using the testing dataset. The computer-aided diagnosis system generated a probability score for each image, and a probability score for each lesion was calculated as the weighted mean with a log₁₀-transformation. Two experts (E1, E2) read the identical testing dataset with a probability score.

RESULTS

The area under the curve of classifier (1) for adenomas was equivalent to E1 and superior to E2 (classifier 86%, E1 86%, E2 69%; classifier vs. E2, p < 0.001). In contrast, the area under the curve of classifier (2) for sessile serrated adenoma/polyps was inferior to both experts (classifier 55%, E1 68%, E2 79%; classifier vs. E2, p < 0.001).

CONCLUSION

The classifier (1) developed using white-light images alone compares favorably with experts in differentiating adenomas from serrated lesions. However, the classifier (2) to identify sessile serrated adenoma/polyps is inferior to experts.

E3 ubiquitin ligase MAGI3 degrades c-Myc and acts as a predictor for chemotherapy response in colorectal cancer

Background

Recurrence and chemoresistance constitute the leading cause of death in colorectal cancer (CRC). Thus, it is of great significance to clarify the underlying mechanisms and identify predictors for tailoring adjuvant chemotherapy to improve the outcome of CRC.

Methods

By screening differentially expressed genes (DEGs), constructing random forest classification and ranking the importance of DEGs, we identified membrane associated guanylate kinase, WW and PDZ domain containing 3 (MAGI3) as an important gene in CRC recurrence. Immunohistochemical and western blot assays were employed to further detect MAGI3 expression in CRC tissues and cell lines. Cell counting kit-8, plate colony formation, flow cytometry, sub-cutaneous injection and azoxymethane plus dextran sulfate sodium induced mice CRC assays were employed to explore the effects of MAGI3 on proliferation, growth, cell cycle, apoptosis, xenograft formation and chemotherapy resistance of CRC. The underlying molecular mechanisms were further investigated through gene set enrichment analysis, quantitative real-time PCR, western blot, co-immunoprecipitation, ubiquitination, GST fusion protein pull-down and immunohistochemical staining assays.

Results

Our results showed that dysregulated low level of MAGI3 was correlated with recurrence and poor prognosis of CRC. MAGI3 was identified as a novel substrate-binding subunit of SKP1-Cullin E3 ligase to recognize c-Myc, and process c-Myc ubiquitination and degradation. Expression of MAGI3 in CRC cells inhibited cell growth, promoted apoptosis and chemosensitivity to fluoropyrimidine-based chemotherapy by suppressing activation of c-Myc in vitro and in vivo. In clinic, the stage II/III CRC patients with MAGI3-high had a significantly good recurrence-free survival (~ 80%, 5-year), and were not necessary for further adjuvant chemotherapy. The patients with MAGI3-medium had a robustly good response rate or recurrence-free survival with fluoropyrimidine-based chemotherapy, and were recommended to undergo fluoropyrimidine-based adjuvant chemotherapy.

Conclusions

MAGI3 is a novel E3 ubiquitin ligase by degradation of c-Myc to regulate CRC development and may act as a potential predictor of adjuvant chemotherapy for CRC patients.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01622-9.

Crucial Role of Oncogenic KRAS Mutations in Apoptosis and Autophagy Regulation: Therapeutic Implications

KRAS, one of the RAS protein family members, plays an important role in autophagy and apoptosis, through the regulation of several downstream effectors. In cancer cells, KRAS mutations confer the constitutive activation of this oncogene, stimulating cell proliferation, inducing autophagy, suppressing apoptosis, altering cell metabolism, changing cell motility and invasion and modulating the tumor microenvironment. In order to inhibit apoptosis, these oncogenic mutations were reported to upregulate anti-apoptotic proteins, including Bcl-xL and survivin, and to downregulate proteins related to apoptosis induction, including thymine-DNA glycosylase (TDG) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). In addition, KRAS mutations are known to induce autophagy in order to promote cell survival and tumor progression through MAPK and PI3K regulation. Thus, these mutations confer resistance to anti-cancer drug treatment and, consequently, result in poor prognosis. Several therapies have been developed in order to overcome KRAS-induced cell death resistance and the downstream signaling pathways blockade, especially by combining MAPK and PI3K inhibitors, which demonstrated promising results. Understanding the involvement of KRAS mutations in apoptosis and autophagy regulation, might bring new avenues to the discovery of therapeutic approaches for CRCs harboring KRAS mutations.

Clinical, Pathologic, Genetics and Intratumoral Immune Milieu of Serrated Adenocarcinoma of the Colon

BACKGROUND

Serrated adenocarcinoma (SAC), a recognized WHO variant of colonic adenocarcinoma, is the purported end-product of serrated neoplasia. Yet, the diagnosis of SAC is infrequently rendered, and little is known about its prognosis, immune microenvironment, and molecular alterations.

MATERIALS AND METHODS

We assessed 903 consecutive colon carcinomas and recognized tumors with ≥5% (n=77) serrated pattern, and ≥50% serrated pattern (n=13). We assessed precursor polyps and synchronous polyps. We recorded demographic/clinical parameters, histological features, and MMR status. We performed immunohistochemistry and quantification on tissue microarray for HLA class I/II proteins, beta-2-microglobulin (B2MG), CD8, CD163, LAG3, PD-L1, FoxP3, PD-L1and BRAF V600E.

RESULTS

We identified ≥ 5% epithelial serration prevalence in 8.5% of cases, and ≥50% epithelial serration prevalence in 1.4% of cases. Precursor lesions were present in 21.4% of cases; these were mostly tubular adenomas with two traditional serrated adenoma identified. SAC with ≥ 5% serrations exhibited lower numbers of CD8 positive lymphocytes (p=0.002) and lower B2MG expression (p=0.048), although neither value was significant at ≥50% serration threshold. There was no difference in HLA class I/II, or PD-L1 expression on tumor cells and no difference in PD-L1, LAG3, FOXP3 and CD163 expression on immune cells. There was no association with MMR status, or BRAFV600E relative to conventional adenocarcinoma. There was improved disease-specific survival on univariate (but not multivariate) analysis between carcinomas with serrated pattern and non-mucinous conventional colonic carcinomas at ≥5% epithelial serrations (p=0.04).

CONCLUSION

SAC category shows a limited impact on survival, and this phenotype may harbor a unique immunologic milieu.

Genome-wide analysis of mRNA expression identified the involvement of trefoil factor 1 in the development of sessile serrated lesions

Precursor lesions that progress into colorectal cancer (CRC) could be largely classified into sessile serrated lesions (SSLs), traditional serrated adenoma (TSA), and tubular adenoma (TA). We aimed to determine whether high expression of trefoil factor 1 (TFF1) is closely associated with serrated lesions, particularly SSLs. The samples were divided into the first (12 SSLs, 5 TSAs, and 15 TAs) and second cohorts (15 SSLs, 9 TSAs, and 15 TAs). First, we investigated TFF1 expression in isolated gland samples using array-based and reverse-transcription PCR. Second, we performed immunohistochemical analysis of TFF1 expression in paraffin-embedded tissues obtained from SSL, TSA, TA, and hyperplastic polyp (HP) samples. In addition, we compared TFF1 mRNA levels between SSLs and HPs. TFF1 expression was significantly higher in SSLs than in TSA and TA in both cohorts. Additionally, immunohistochemical staining of TFF1 in the HP, SSL, TSA, and TA samples revealed significant differences in the immunohistochemical scores of TFF1 among the four types of lesions (higher expression in SSLs than in the other three lesions). Finally, there were significant differences in TFF1 mRNA expression levels between SSLs and HPs in paraffin-embedded tissues. However, there was considerable overlap in the immunohistochemical scores and expression levels of TFF1 transcripts between SSLs and HPs. The current findings may help elucidate the molecular mechanisms involved in serrated lesion development. In addition, we suggest that despite the limited practical application, upregulation of TFF1 transcripts may help differentiate SSLs from other lesions.