Difference Between Left-Sided and Right-Sided Colorectal Cancer: A Focused Review of Literature

Diagnostic and screening potential of plasma exosome miR‑99b‑5p and its combination with other miRNAs for colorectal cancer

Extracellular vesicles (EVs) secreted by tumor cells have been documented to hold viable biomarker potential. Therefore, the present study evaluated the potential clinical value of EV-microRNAs (miRNAs or miRs) in the plasma exosomes of patients with colorectal cancer (CRC) for the early diagnosis and screening of CRC. In total, 95 plasma samples were collected at The Third Affiliated Hospital of Guangzhou Medical University (Guangzhou, China) between 2017 and 2019. Specifically, 68 samples were from patients with CRC and 27 were from healthy control (HC) donors. High-throughput sequencing was used to detect the expression of miRNAs in the isolated plasma EVs, which was subsequently verified by reverse transcription-quantitative PCR. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic potential of single and combined miRNAs for CRC. Bioinformatics analysis was employed to predict the target genes of candidate miRNAs. Compared with those in the HC group, the CRC group expressed higher levels of miR-99b-5p and miR-409-3p, especially during the early stages of CRC. Clinicopathological analysis confirmed the higher expression levels of miR-99b-5p during the early stages, as well as higher expression levels in the colon compared with those in the rectum. ROC curve analysis revealed that the area under the curve (AUC) of miR-99b-5p for the diagnosis of early CRC was 73.5% (P=0.007). The early diagnostic capability of miR-99b-5p combined with miR-409-3p for CRC was evaluated, and the AUC was found to be 74.1% (P=0.006). In addition, the AUC of the combination of miR-99b-5p, miR-409-3p and carcinoembryonic antigen was 81.2% (P<0.001), indicating that this three-parameter combination displayed higher diagnostic power compared with any single miRNA for early CRC screening. The results from the present study suggest that the expression of miR-99b-5p in plasma exosomes is significantly upregulated in CRC, which holds potential for the early diagnosis of this cancer type. Such potential can be enhanced further by combining it with other miRNAs. Therefore, the present study provides a comprehensive but preliminary insight for the viability of miR-99b-5p (alone or combined with other miRNAs) for CRC diagnosis, which requires further exploration in the future.

Long-term effects of once-only flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: 21-year follow-up of the UK Flexible Sigmoidoscopy Screening randomised controlled trial

BACKGROUND

Flexible sigmoidoscopy screening reduces colorectal cancer incidence and mortality; however, uncertainty exists about the duration of protection and differences by sex and age. We assessed effects of once-only flexible sigmoidoscopy screening after 21 years' follow-up.

METHODS

The UK Flexible Sigmoidoscopy Screening Trial is a multicentre randomised controlled trial that recruited men and women aged 55-64 years from general practices serving 14 hospitals. Among participants indicating that they would attend flexible sigmoidoscopy screening if invited, randomisation (2:1) to the control (no further contact) or intervention (invited to once-only flexible sigmoidoscopy screening) group was performed centrally in blocks of 12, stratified by centre, general practice, and household type. Masking of intervention was infeasible. Primary outcomes were colorectal cancer incidence and mortality. The Kaplan-Meier method estimated cumulative incidence. Primary analyses estimated intention-to-treat hazard ratios (HRs) and risk differences, overall and stratified by subsite, sex, and age. The trial is registered with ISRCTN, number 28352761.

FINDINGS

Among participants recruited between Nov 14, 1994, and March 30, 1999, 170 432 were eligible and 113 195 were randomly assigned to the control group and 57 237 were randomly assigned to the intervention group. 406 participants were excluded from analyses (268 in the control group and 138 in the intervention group), leaving 112 927 participants in the control group (55 336 [49%] men and 57 591 [51%] women) and 57 099 in the intervention group (27 966 [49%] men and 29 103 [51%] women). Of participants who were invited to be screened, 40 624 (71%) attended screening. Median follow-up was 21·3 years (IQR 18·0-22·2). In the invited-to-screening group, colorectal cancer incidence was reduced compared with the control group (1631 vs 4201 cases; cumulative incidence at 21 years was 3·18% [95% CI 3·03 to 3·34] vs 4·16% [4·04 to 4·29]; HR 0·76 [95% CI 0·72 to 0·81]) with 47 fewer cases per 100 000 person-years (95% CI -56 to -37). Colorectal cancer mortality was also reduced in the invited-to-screening group compared with the control group (502 vs 1329 deaths; cumulative incidence at 21 years was 0·97% [0·88 to 1·06] vs 1·33% [1·26 to 1·40]; HR 0·75 [0·67 to 0·83]) with 16 fewer deaths per 100 000 person-years (-21 to -11). Effects were particularly evident in the distal colorectum (726 incident cancer cases in the invited-to-screening group vs 2434 cases in the control group; HR 0·59 [0·54 to 0·64]; 47 fewer cases per 100 000 person-years [-54 to -41]; 196 cancer deaths in the invited-to-screening group vs 708 deaths in the control group; HR 0·55 [0·47 to 0·64]; 15 fewer deaths per 100 000 person-years [-19 to -12]) and not the proximal colon (871 incident cancer cases in the invited-to-screening group vs 1749 cases in the control group; HR 0·98 [0·91 to 1·07]; one fewer case per 100 000 person-years [-8 to 5]; 277 cancer deaths in the invited-to-screening group vs 547 deaths in the control group; HR 1·00 [0·86 to 1·15]; zero fewer deaths per 100 000 person-years [-4 to 4]). The HR for colorectal cancer incidence was lower in men (0·70 [0·65-0·76]) than women (0·86 [0·79 to 0·93]; pinteraction=0·0007) but there was no difference by age.

INTERPRETATION

We show that once-only flexible sigmoidoscopy screening reduces colorectal cancer incidence and mortality for two decades and provide important data to inform colorectal cancer screening guidelines.

FUNDING

National Institute for Health and Care Research Health Technology Assessment Programme and the Medical Research Council.

Right vs. Left colorectal cancer - Where do we draw the line?

PURPOSE

No consensus on the definition of right and left colorectal cancer (CRC) exists, nor studies offering histological or molecular basis for such categorisation. This study investigated the regional variations in the histological and molecular characteristics of CRCs, with the objective of determining an optimal division point between right and left CRCs.

MATERIALS AND METHODS

An observational study of consecutive patients who underwent CRC resection (1995-2022) at Concord Hospital, Sydney was performed. Clinicopathological data were extracted from a prospective database and seven permutations of right-left divisions considered. Logistic regression tested association between the right-left divisions and pathological characteristics. Receiver operating characteristic and area under the curve (AUC) analyses determined the discriminative ability of each division to predict 18 pathology characteristics.

RESULTS

3753 patients underwent a CRC resection (2120 male; mean 69.5yrs [SD12.6]). There was regional variation in tumours with respect to tumour infiltrating lymphocytes (TILs), mismatch repair deficiency (dMMR), and mutant BRAF (mBRAF). Left-sided tumours were less likely to demonstrate TILs (P < 0.001), be dMMR (P < 0.001), and express mBRAF (P < 0.001). Division at the descending-sigmoid junction yielded highest discriminative abilities: TILs - AUC 0.66, dMMR - AUC 0.76, and mBRAF - AUC 0.73.

CONCLUSION

This is the first study to provide a pathological basis on which right- and left-sided cancers may be defined, and found the optimal division point between the right and left colorectum to be at the descending-sigmoid junction. Further research is needed to determine whether this can facilitate individualised patient management.

Trends in colorectal cancer surgical resection rates during the screening era: a retrospective study in Italy

BACKGROUND

Faecal immunochemical test (FIT)-based screening is effective in reducing colorectal cancer (CRC) incidence, but its sensitivity for proximal lesions remains low.

OBJECTIVES

We compared age-adjusted CRC surgical resection rates across anatomic sites (proximal colon, distal colon, rectum), age groups and sex over 20 years in a large Italian population. We particularly focused on changes in trends following FIT-screening implementation in the target population (50-69 years).

DESIGN

This retrospective study analysed data from the Veneto Region's administrative Hospital Discharge Dataset, involving over 54 000 patients aged 40-89 (43.4% female) who underwent CRC surgery between 2002 and 2021.

RESULTS

Overall, surgery rates increased until 2007 (annual percentage changes: 2.5% in males, 2.9% in females) and then declined (-4.2% in males, -3.4% in females). This decline was steeper for distal and rectal cancers compared with proximal cancer, suggesting a shift towards more right-sided CRC surgery.In males, the prescreening increase in proximal surgery was reversed after screening implementation (slope change: -6%) while the prescreening decline accelerated for distal (-4%) and rectal (-3%) surgeries. In females, stable prescreening trends shifted downward for all sites (-5% for proximal, -8% for distal and -7% for rectal surgery). However, the change in trends between prescreening and postscreening periods was not different across anatomic sites for either sex (all slope change differences in pairwise comparisons were not statistically significant).

CONCLUSION

The shift towards proximal surgery may not be entirely due to the FIT's low sensitivity but may reflect an underlying upward trend in proximal cancers independent of screening.

Development of a Global Metabo-Lipid-Prote-omics Workflow to Compare Healthy Proximal and Distal Colonic Epithelium in Mice

A multimetabo-lipid-prote-omics workflow was developed to characterize the molecular interplay within proximal (PC) and distal (DC) colonic epithelium of healthy mice. This multiomics data set lays the foundation to better understand the two tissue types and can be used to study, for example, colon-related diseases like colorectal cancer or inflammatory bowel disease. First, the methyl tert-butyl ether extraction method was optimized, so that from a single tissue biopsy >350 reference-matched metabolites, >1850 reference-matched lipids, and >4500 proteins were detected by using targeted and untargeted metabolomics, untargeted lipidomics, and proteomics. Next, each omics-data set was analyzed individually and then merged with the additional omics disciplines to generate a deep understanding of the underlying complex regulatory network within the colon. Our data demonstrates, for example, differences in mucin formation, detected on substrate level as well as on enzyme level, and altered lipid metabolism by the detection of phospholipases hydrolyzing sphingomyelins to ceramides. In conclusion, the combination of the three mass spectrometry-based omics techniques can better entangle the functional and regional differences between PC and DC tissue compared to each single omics technique.

[Gender medicine in peritoneal diseases]

Diseases of the peritoneum are divided into benign and malignant, whereby malignant diseases are more frequent. The incidence of peritoneal metastases is difficult to determine as they are frequently not listed separately in cancer databases and registries. Peritoneal metastases can be caused by many primary tumors but are particularly frequent in gastric, ovarian and colorectal carcinomas. Systemic chemotherapy shows gender-specific differences in the tolerability, especially gastrointestinal side effects and hematological toxicity occur more often in women. Surgical treatment options in selected patients include cytoreductive surgery with or without hyperthermic intraperitoneal chemoperfusion (HIPEC). The treatment recommendations depend on the primary tumor entity and the stage of the disease. Hysterectomy and/or salpingo-oophorectomy is often necessary during cytoreductive surgery. As the incidence of cancerous diseases is increasing in younger patients, the aspect of fertility is becoming increasingly more important. The iatrogenically induced menopause is another aspect that needs to be addressed after these types of procedures. Women with gastric and colorectal cancer tend to have a slightly better survival rate, especially in localized tumors; however, in advanced tumor stages the survival rates are comparable. Even if gender-specific differences in incidence, treatment response and adverse events are conspicuous, there is so far no exact explanation for these differences. More studies are needed in order to treat both genders as adequately as possible, with low adverse events and to achieve the best possible outcome.

High Probability of Lynch Syndrome Among Colorectal Cancer Patients Is Associated With Higher Occurrence of KRAS and PIK3CA Mutations

Background

In Indonesia, early-onset colorectal cancer (EOCRC) rates are higher in patients < 50 years old compared to Western populations, possibly due to a higher frequency of Lynch syndrome (LS) in CRC patients. We aimed to examine the association of KRAS and PIK3CA mutations with LS.

Methods

In this retrospective cross-sectional single-center study, the PCR-HRM-based test was used for screening of microsatellite instability (MSI) mononucleotide markers (BAT25, BAT26, BCAT25, MYB, EWSR1), MLH1 promoter methylation, and oncogene mutations of BRAF (V600E), KRAS (exon 2 and 3), and PIK3CA (exon 9 and 20) in FFPE DNA samples.

Results

All the samples (n = 244) were from Dr. Sardjito General Hospital Yogyakarta, Indonesia. KRAS and PIK3CA mutations were found in 151/244 (61.88%) and 107/244 (43.85%) of samples, respectively. KRAS and PIK3CA mutations were significantly associated with MSI status in 32/42 (76.19%) and 25/42 (59.52%) of samples, respectively. KRAS mutation was significantly associated with LS status in 26/32 (81.25%) of samples. The PIK3CA mutation was present in a higher proportion in LS samples of 19/32 (59.38%), but not statistically significant. Clinicopathology showed that KRAS mutation was significantly associated with right-sided CRC and higher histology grade in 39/151 (25.83%) and 24/151 (16.44%) samples, respectively. PIK3CA mutation was significantly associated with female sex and lower levels of tumor-infiltrating lymphocytes in 62/107 (57.94%) and 26/107 (30.23%) samples, respectively. KRAS and PIK3CA mutations did not significantly affect overall survival (120 months) in LS and non-LS patients.

Conclusions

The high probability of LS in Indonesian CRC patients is associated with KRAS and PIK3CA mutations.

Markers of Epithelial-Mesenchymal Transition and Mucinous Histology Are Significant Predictors of Disease Severity and Tumor Characteristics in Early-Onset Colorectal Cancer

Approximately 20% of patients with colorectal cancer (CRC) are diagnosed with a mucinous subtype of this tumor, have a worse prognosis, and often show resistance to available therapies. Molecules from the mucin family are involved in the regulation of epithelial-mesenchymal transition (EMT), which significantly determines the cancer aggressiveness. This study aimed to examine the diagnostic and prognostic significance of mucinous histology and EMT markers in patients with early-onset CRC and their association with disease severity and tumor characteristics. This study included tumor tissue samples from 106 patients diagnosed with CRC before the age of 45, 53 with mucinous and 53 with non-mucinous tumors. The EMT status was determined by immunohistochemical analysis of E-cadherin and Vimentin in tissue sections. Mucinous tumors had significantly higher Mucin-1 (p < 0.001) and cytoplasmic E-cadherin (p = 0.043) scores; they were significantly less differentiated (p = 0.007), more advanced (p = 0.027), and predominately affected right the colon (p = 0.039) compared to non-mucinous tumors. Epithelial tumors were significantly better differentiated (p = 0.034) and with less prominent tumor budding (p < 0.001) than mesenchymal tumors. Mucin-1 and Vimentin were independent predictors of tumor differentiation (p = 0.006) and budding (p = 0.001), respectively. Mucinous histology and EMT markers are significant predictors of disease severity and tumor characteristics in early-onset colorectal cancer.

The relationship between Stroma AReactive Invasion Front Areas (SARIFA), Warburg-subtype and survival: results from a large prospective series of colorectal cancer patients

BACKGROUND

Stroma AReactive Invasion Front Areas (SARIFA) is a recently identified haematoxylin & eosin (H&E)based histopathologic biomarker in gastrointestinal cancers, including colorectal cancer (CRC), defined as direct contact between tumour cells and adipocytes at the tumour invasion front. The current study aimed at validating the prognostic relevance of SARIFA in a large population-based CRC series as well as at investigating the relationship between SARIFA-status and previously established Warburg-subtypes, both surrogates of the metabolic state of the tumour cells.

METHODS

SARIFA-status (positive versus negative) was determined on H&E slides of 1,727 CRC specimens. Warburg-subtype (high versus moderate versus low) data was available from our previous study. The associations between SARIFA-status, Warburg-subtype, clinicopathological characteristics and CRC-specific as well as overall survival were investigated.

RESULTS

28.7% (n=496) CRC were SARIFA-positive. SARIFA-positivity was associated with more advanced disease stage, higher pT category, and more frequent lymph node involvement (all p<0.001). SARIFA-positivity was more common in Warburg-high CRC. 44.2% (n=219) of SARIFA-positive CRCs were Warburg-high compared to 22.8% (n=113) being Warburg-low and 33.1% (n=164) being Warburg-moderate (p<0.001). In multivariable-adjusted analysis, patients with SARIFA-positive CRCs had significantly poorer CRC-specific (HRCRC-specific 1.65; 95% CI 1.41-1.93) and overall survival (HRoverall survival 1.46; 95% CI 1.28-1.67) independent of clinically known risk factors and independent of Warburg-subtype. Combining the SARIFA-status and the Warburg-subtype to a combination score (SARIFA-negative/Warburg-high versus SARIFA-positive/Warburg-low versus SARIFA-positive/Warburg-high, and so on) did not improve the survival prediction compared to the use of SARIFA-status alone (SARIFA-negative + Warburg-high: HRCRC-specific 1.08; 95% CI 0.84-1.38; SARIFA-positive + Warburg-low: HRCRC-specific 1.79; 95% CI 1.32-2.41; SARIFA-positive + Warburg-high: HRCRC-specific 1.58; 95% CI 1.23-2.04).

CONCLUSIONS

Our current study is the by far largest external validation of SARIFA-positivity as a novel independent negative prognostic H&E-based biomarker in CRC. In addition, our study shows that SARIFA-positivity is associated with the Warburg-high subtype. Further research is warranted to provide a more mechanistic understanding of the underlying tumour biology. Based on our data, we conclude SARIFA-status should be implemented in pathologic routine practice to stratify CRC patients.

Maintenance proton pump inhibitor use and risk of colorectal cancer: a Swedish retrospective cohort study

OBJECTIVES

We aimed to evaluate the risk of colorectal adenocarcinoma (CRA) associated with long-term use of proton pump inhibitors (PPIs) in a large nationwide cohort.

DESIGN

Retrospective cohort study.

SETTING

This research was conducted at the national level, encompassing the entire population of Sweden.

PARTICIPANTS

This study utilised Swedish national registries to identify all adults who had ≥180 days of cumulative PPI use between July 2005 and December 2012, excluding participants who were followed up for less than 1 year. A total of 754 118 maintenance PPI users were included, with a maximum follow-up of 7.5 years.

INTERVENTIONS

Maintenance PPI use (cumulative≥180 days), with a comparator of maintenance histamine-2 receptor antagonist (H2RA) use.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the risk of CRA, presented as standardised incidence ratios (SIRs) with 95% confidence intervals (CIs). Subgroup analyses were performed to explore the impact of indications, tumour locations, tumour stages and the duration of follow-up. A multivariable Poisson regression model was fitted to estimate the incidence rate ratios (IRRs) and 95% CIs of PPI versus H2RA use.

RESULTS

Maintenance PPI users exhibited a slightly elevated risk of CRA compared to the general population (SIR 1.10, 95% CI=1.06 to 1.13) for both men and women. Individuals aged 18-39 (SIR 2.79, 95% CI=1.62 to 4.47) and 40-49 (SIR 2.02, 95% CI=1.65 to 2.45) had significantly higher risks than the general population. Right-sided CRA showed a higher risk compared to the general population (SIR 1.26, 95% CI=1.20 to 1.32). There was no significant difference in the risk of CRA between maintenance PPI users and maintenance H2RA users (IRR 1.05, 95% CI=0.87 to 1.27, p<0.05).

CONCLUSIONS

Maintenance PPI use may be associated with an increased risk of CRA, but a prolonged observation time is needed.

Characteristics and outcomes of large (≥5 cm) colonic adenocarcinomas and comparing outcomes of minimally invasive and open surgery for stage I to III disease

BACKGROUND

Colon cancer prognosis is primarily dependent on the stage at diagnosis, but tumor size and location may also impact prognosis. This study aimed to assess the characteristics and outcomes of patients with ≥5 cm colonic adenocarcinomas and compare outcomes of open and minimally invasive surgery for stage I to III large colonic adenocarcinomas.

METHODS

The National Cancer Database (2010-2019) was searched for patients with colonic adenocarcinomas ≥5 cm. Outcomes of patients who underwent minimally invasive surgery or open surgery were compared after propensity-score matching. The primary outcome was 5-year overall survival and, secondarily, hospital stay, surgical margins, and short-term mortality.

RESULTS

A total of 126,959 patients were included (22.1% of all diagnosed adenocarcinomas). 56% of tumors were right-sided, 32.6% were left-sided, and 11.4% were in the transverse colon. Stage IV disease was recorded in 34.6% of patients. Lymphovascular invasion, perineural invasion, and Kirsten rat sarcoma viral oncogene homolog mutations were recorded in 35.7%, 14.9%, and 41.6% of patients. The rate of positive surgical margins was 9.8%. Median hospital stay was 6 (interquartile range: 4-8) days. 30- and 90-day mortality rates were 4.1% and 7.5%, respectively. After matching, 15,228 patients in the open surgery group were matched to a similar number in the minimally invasive surgery group. The minimally invasive surgery group was associated with significantly lower rates of 30- and 90-day mortality, positive surgical margins, shorter hospital stay, and longer median overall survival (110.6 vs 86.6 months, P < .001) than did open surgery.

CONCLUSION

Large colonic adenocarcinomas are mostly right-sided or transverse and present at a more advanced stage with adverse pathologic features. Minimally invasive surgery was associated with better overall survival and short-term benefits when compared with open surgery.

NFκB signalling in colorectal cancer: Examining the central dogma of IKKα and IKKβ signalling

The NFκB pathway, known as the central regulator of inflammation, has a well-established role in colorectal cancer (CRC) initiation, progression, and therapy resistance. Due to the pathway's overarching roles in CRC, there have been efforts to characterise NFκB family members and target the pathway for therapeutic intervention. Initial research illustrated that the canonical NFκB pathway, driven by central kinase IKKβ, was a promising target for drug intervention. However, dose limiting toxicities and specificity concerns have resulted in failure of IKKβ inhibitors in clinical trials. The field has turned to look at targeting the less dominant kinase, IKKα, which along with NFκB inducing kinase (NIK), drives the lesser researched non-canonical NFκB pathway. However prognostic studies of the non-canonical pathway have produced conflicting results. There is emerging evidence that IKKα is involved in other signalling pathways, which lie outside of canonical and non-canonical NFκB signalling. Evidence suggests that some of these alternative pathways involve a truncated form of IKKα, and this may drive poor cancer-specific survival in CRC. This review aims to explore the multiple components of NFκB signalling, highlighting that NIK may be the central kinase for non-canonical NFκB signalling, and that IKKα is involved in novel pathways which promote CRC.

Differences in the molecular organisation of tumours along the colon are linked to interactions within the tumour ecosystem

Tumours exhibit significant heterogeneity in their molecular profiles across patients, largely influenced by the tissue of origin, where certain driver gene mutations are predominantly associated with specific cancer types. Here, we unveil an additional layer of complexity: some cancer types display anatomic location-specific mutation profiles akin to tissue-specificity. To better understand this phenomenon, we concentrate on colon cancer. While prior studies have noted changes of the frequency of molecular alterations along the colon, the underlying reasons and whether those changes occur rather gradual or are distinct between the left and right colon, remain unclear. Developing and leveraging stringent statistical models on molecular data from 522 colorectal tumours from The Cancer Genome Atlas, we reveal disparities in molecular properties between the left and right colon affecting many genes. Interestingly, alterations in genes responsive to environmental cues and properties of the tumour ecosystem, including metabolites which we quantify in a cohort of 27 colorectal cancer patients, exhibit continuous trends along the colon. Employing network methodologies, we uncover close interactions between metabolites and genes, including drivers of colon cancer, showing continuous abundance or alteration profiles. This underscores how anatomic biases in the composition and interactions within the tumour ecosystem help explaining gradients of carcinogenesis along the colon.

DNA-methylation variability in normal mucosa: a field cancerization marker in patients with adenomatous polyps

BACKGROUND

The phenomenon of field cancerization reflects the transition of normal cells into those predisposed to cancer. Assessing the scope and intensity of this process in the colon may support risk prediction and colorectal cancer prevention.

METHODS

The Swiss Epigenetic Colorectal Cancer Study (SWEPIC) study, encompassing 1111 participants for DNA methylation analysis and a subset of 84 for RNA sequencing, was employed to detect field cancerization in individuals with adenomatous polyps (AP). Methylation variations were evaluated for their discriminative capability, including in external cohorts, genomic localization, clinical correlations, and associated RNA expression patterns.

RESULTS

Normal cecal tissue of individuals harboring an AP in the proximal colon manifested dysregulated DNA methylation compared to tissue from healthy individuals at 558 unique loci. Leveraging these adenoma-related differentially variable and methylated CpGs (aDVMCs), our classifier discerned between healthy and AP-adjacent tissues across SWEPIC datasets (cross-validated area under the receiver operating characteristic curve [ROC AUC] = 0.63-0.81), including within age-stratified cohorts. This discriminative capacity was validated in 3 external sets, differentiating healthy from cancer-adjacent tissue (ROC AUC = 0.82-0.88). Notably, aDVMC dysregulation correlated with polyp multiplicity. More than 50% of aDVMCs were significantly associated with age. These aDVMCs were enriched in active regions of the genome (P < .001), and associated genes exhibited altered expression in AP-adjacent tissues.

CONCLUSIONS

Our findings underscore the early onset of field cancerization in the right colon during the neoplastic transformation process. A more extensive validation of aDVMC dysregulation as a stratification tool could pave the way for enhanced surveillance approaches, especially given its linkage to adenoma emergence.

Colorectal Oncologic Emergencies: Recognition, Management, and Outcomes

Colorectal cancer is the third most frequent type of malignancy in the United States, and the age at diagnosis is decreasing. Although the goal of screening is focused on prevention and early detection, a subset of patients inevitably presents as oncologic emergencies. Approximately 15% of patients with colorectal cancer will present as surgical emergencies, with the majority being due to either colonic perforation or obstruction. Patients presenting with colorectal emergencies are a challenging cohort, as they often present at an advanced stage with an increase in T stage, lymphovascular invasion, and metachronous liver disease.

Relief of Obstruction in Left-Sided Obstructive Colon Cancer: Nationwide Analysis of Applied Treatment in the Palliative Setting

BACKGROUND

For relief of bowel obstruction in left-sided obstructive colon cancer (LSOCC), a self-expandable metal stent (SEMS) or decompressing stoma (DS) can be placed. In a curative setting, these two strategies have been extensively studied as a bridge to elective resection. Guidelines recommend SEMS as the preferred option in the palliative setting, but adherence in daily practice is unknown. Therefore, this study aimed to gain more insight into patients with LSOCC who received palliative treatment with SEMS or DS at a national level.

METHODS

A retrospective population-based cohort study was conducted in the Netherlands. Data from the Netherlands Cancer Registry (NCR) on all patients with LSOCC treated with DS or SEMS not followed by resection of the primary tumour between January 1, 2015, and December 31, 2019, were analysed. Type of treatment (DS or SEMS) for different clinical scenarios, was the main outcome of this study, and was also evaluated over the years (2015-2019).

RESULTS

Palliative treatment with SEMS or DS for LSOCC was performed in 1077 patients, of whom 79.2% had metastatic disease (M1). Patients without metastatic disease (M0) were older (≥ 80 years M0 67.4%, M1 25.3%, P < 0.001), had a worse clinical condition (ASA III 51.4% versus 36.37%, ASA IV-V 13.3% versus 4.0% P < 0.001) and presented with higher tumour stage (cT4 55.4% versus 33.5%, % P < 0.001). DS was performed in 91.5% of the patients and SEMS in 8.5%. The proportion of DS did not significantly differ between patients with M1 and M0 (91.8% vs. 90.2% respectively, P = 0.525). No increase in SEMS application was observed over the years, with a stable overall proportion of DS of 91-92% per year. In the multivariable analyses, ninety-day mortality and overall survival were not significantly different between SEMS and DS.

CONCLUSIONS

This study revealed that DS was the primary treatment modality for palliative management of LSOCC in the Netherlands between 2015 and 2019, while the guidelines recommended SEMS as preferred treatment. For patients with LSOCC eligible for stenting in the palliative setting, SEMS placement should become more available and accessible as the preferred treatment option, to avoid a stoma in the terminal phase of life.

An overview of chemically induced rodent models for sporadic colorectal cancer: Histopathological and translational perspectives

Globally, colorectal cancer (CRC) is one of the most frequently diagnosed human gastrointestinal neoplasia and the second leading cause of cancer-related death in both men and women. Despite considerable efforts currently devoted to the study of the biology and treatment of CRC, patient prognosis and survival are still poor. Sporadic CRC is a complex multistep disease and usually emerges in the setting of lifestyle and dietary changes mainly observed in industrialized countries with high human development index (HDI) (westernized style). The molecular pathogenesis of sporadic CRC presents genetic heterogeneity with APC, RAS, PIK3CA, TGFBR, SMAD4, and TP53 mutations usually detected during the progression of this malignancy. The establishment of sporadic CRC models has become essential for both basic and translational research to improve our understanding of the pathophysiology, unravel new molecular drivers, and preventive/therapeutic improvement of this malignancy. Chemically induced rodent models of sporadic CRC recapitulate most key morphological and genetic/epigenetic events observed during the promotion and progression of this malignancy, establishing effective diagnostic and prevention strategies to be translated into clinical practice. The present review gathers the main features of the state-of-the-art evidence on chemically induced rodent models, widely applied for translational modelling of sporadic CRC with a specific focus on histopathology and prevention perspectives. Our narrative review reinforces the persistent value of these bioassays and encourages the use of multimodel strategies for further investigations.

Microsatellite Instability Testing and Prognostic Implications in Colorectal Cancer

Given the crucial predictive implications of microsatellite instability (MSI) in colorectal cancer (CRC), MSI screening is commonly performed in those with and at risk for CRC. Here, we compared results from immunohistochemistry (IHC) and the droplet digital PCR (ddPCR) MSI assay on formalin-fixed paraffin-embedded tumor samples from 48 patients who underwent surgery for colon and rectal cancer by calculating Cohen's kappa measurement (k), revealing high agreement between the methods (k = 0.915). We performed Kaplan-Meier survival analyses and univariate and multivariate Cox regression to assess the prognostic significance of ddPCR-based MSI and to identify clinicopathological features associated with CRC outcome. Patients with MSI-high had better overall survival (OS; p = 0.038) and disease-free survival (DFS; p = 0.049) than those with microsatellite stability (MSS). When stratified by primary tumor location, right-sided CRC patients with MSI-high showed improved DFS, relative to those with MSS (p < 0.001), but left-sided CRC patients did not. In multivariate analyses, MSI-high was associated with improved OS (hazard ratio (HR) = 0.221, 95% confidence interval (CI): 0.026-0.870, p = 0.042), whereas the loss of DNA mismatch repair protein MutL homolog 1 (MLH1) expression was associated with worse OS (HR = 0.133, 95% CI: 0.001-1.152, p = 0.049). Our results suggest ddPCR is a promising tool for MSI detection. Given the opposing effects of MSI-high and MLH1 loss on OS, both ddPCR and IHC may be complementary for the prognostic assessment of CRC.

Analysis of the nischarin expression across human tumor types reveals its context-dependent role and a potential as a target for drug repurposing in oncology

Nischarin was reported to be a tumor suppressor that plays a critical role in breast cancer initiation and progression, and a positive prognostic marker in breast, ovarian and lung cancers. Our group has found that nischarin had positive prognostic value in female melanoma patients, but negative in males. This opened up a question whether nischarin has tumor type-specific and sex-dependent roles in cancer progression. In this study, we systematically examined in the public databases the prognostic value of nischarin in solid tumors, regulation of its expression and associated signaling pathways. We also tested the effects of a nischarin agonist rilmenidine on cancer cell viability in vitro. Nischarin expression was decreased in tumors compared to the respective healthy tissues, most commonly due to the deletions of the nischarin gene and promoter methylation. Unlike in healthy tissues where it was located in the cytoplasm and at the membrane, in tumor tissues nischarin could also be observed in the nuclei, implying that nuclear translocation may also account for its cancer-specific role. Surprisingly, in several cancer types high nischarin expression was a negative prognostic marker. Gene set enrichment analysis showed that in tumors in which high nischarin expression was a negative prognostic marker, signaling pathways that regulate stemness were enriched. In concordance with the findings that nischarin expression was negatively associated with pathways that control cancer growth and progression, nischarin agonist rilmenidine decreased the viability of cancer cells in vitro. Taken together, our study lays a ground for functional studies of nischarin in a context-dependent manner and, given that nischarin has several clinically approved agonists, provides rationale for their repurposing, at least in tumors in which nischarin is predicted to be a positive prognostic marker.

Clinicopathological Differences between Right and Left Colorectal Cancer by Sex

Background: Until now, studies on colorectal cancer (CRC) have focused on clinicopathological characteristics based on location without considering sex differences. However, as men and women have fundamentally different physiological characteristics, research results in the clinical field are limited. We aimed to elucidate the differences in the clinicopathological characteristics between right-sided CRC (RCC) and left-sided CRC (LCC) according to sex. Methods: We classified 1492 South Korean patients with no history of colon surgery between July 2005 and June 2015 based on tumor location and sex. For these patients, differences in the clinical characteristics according to sex were compared using univariate and multivariate analyses. Results: Of the 1269 patients, 951 (74.9%) had LCC, and 318 (25.1%) had RCC, making LCC approximately three times more common than RCC. When sex was not taken into account, patients with RCC had significantly higher rates of anemia and undifferentiated cancers than the rates in those with LCC. Even considering sex, anemia and undifferentiated cancer were more prevalent in RCC than in LCC in both men and women. In contrast, age over 65 years and abnormal white blood cell count differed between RCC and LCC only in women. Conclusions: The clinicopathologic characteristics of CRC vary according to the location and sex. Therefore, sex must be considered as a fundamental characteristic of personalized treatment.

Short- and long-term outcome differences between patients undergoing left and right colon cancer surgery: cohort study

PURPOSE

Since the literature currently provides controversial data on the postoperative outcomes following right and left hemicolectomies, we carried out this study to examine the short- and long-term treatment outcomes.

METHODS

This study included consecutive patients who underwent right or left-sided colonic resections from year 2014 to 2018 and then they were followed up. The short-term outcomes such as postoperative morbidity and mortality according to Clavien-Dindo score, duration of hospital stay, and 90-day readmission rate were evaluated as well as long-term outcomes of overall survival and disease-free survival. Multivariable Cox regression analysis was performed of overall and progression-free survival.

RESULTS

In total, 1107 patients with colon tumors were included in the study, 525 patients with right-sided tumors (RCC) and 582 cases with tumors in the left part of the colon (LCC). RCC group patients were older (P < 0.001), with a higher ASA score (P < 0.001), and with more cardiovascular comorbidities (P < 0.001). No differences were observed between groups in terms of postoperative outcomes such as morbidity and mortality, except 90-day readmission which was more frequent in the RCC group. Upon histopathological analysis, the RCC group's patients had more removed lymph nodes (29 ± 14 vs 20 ± 11, P = 0.001) and more locally progressed (pT3-4) tumors (85.4% versus 73.4%, P = 0.001). Significantly greater 5-year overall survival and disease-free survival (P = 0.001) were observed for patients in the LCC group, according to univariate Kaplan-Meier analysis.

CONCLUSIONS

Patients with right-sided colon cancer were older and had more advanced disease. Short-term surgical outcomes were similar, but patients in the LCC group resulted in better long-term outcomes.

High-tissue FRMD6 expression predicts better outcomes among colorectal cancer patients

INTRODUCTION

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths. The hippo pathway works as a regulator of organ growth and is often a target for mutations in cancer. Ferm domain containing protein 6 (FRMD6) is an activator of the hippo pathway. This study aimed to explore the role of FRMD6 in CRC and to determine how well it works as a prognostic factor among CRC patients.

METHODS

The tumor expression of FRMD6 was evaluated using immunohistochemistry in 538 colorectal patients operated on at Helsinki University Hospital. We assessed FRMD6 expression with clinicopathological parameters and the impact of FRMD6 expression on survival.

RESULTS

Patients with a high FRMD6 expression exhibited a better prognosis (univariable hazard ratio [HR] 0.58, 95% confidence interval [CI] 0.41-0.81), with a 5-year disease-specific survival (DSS) of 66.3%. By contrast, patients with a low FRMD6 expression had a 5-year DSS of 52.8%. A high FRMD6 expression level served as an independent predictor for better survival in the Cox multivariable survival analysis (HR 0.53, 95% CI 0.33-0.86).

DISCUSSION

To our knowledge, this is the first study to show that a high FRMD6 expression is an independent marker for a better prognosis in CRC and could help determine the prognosis for CRC patients.

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.

The histological and molecular characteristics of early-onset colorectal cancer: a systematic review and meta-analysis

Background

Early-onset colorectal cancer (CRC), defined as diagnosis before age 50, has increased in recent decades. Although more often diagnosed at advanced stage, associations with other histological and molecular markers that impact prognosis and treatment remain to be clarified. We conducted a systematic review and meta-analysis concerning the prevalence of prognostic and predictive tumor markers for early- vs. late-onset CRC, including oncogene mutations, microsatellite instability (MSI), and emerging markers including immune cells and the consensus molecular subtypes.

Methods

We systematically searched PubMed for original research articles published between April 2013-January 2024. Included studies compared the prevalence of tumor markers in early- vs. late-onset CRC. A meta-analysis was completed and summary odds ratios (ORs) with 95% confidence intervals (CIs) were obtained from a random effects model via inverse variance weighting. A sensitivity analysis was completed to restrict the meta-analysis to studies that excluded individuals with Lynch syndrome, a hereditary condition that influences the distribution of tumor markers for early-onset CRC.

Results

In total, 149 articles were identified. Tumors from early-onset CRC are less likely to include mutations in KRAS (OR, 95% CI: 0.91, 0.85-0.98), BRAF (0.63, 0.51-0.78), APC (0.70, 0.58-0.84), and NRAS (0.88, 0.78-1.00) but more likely to include mutations in PTEN (1.68, 1.04-2.73) and TP53 (1.34, 1.24-1.45). After limiting to studies that excluded Lynch syndrome, the associations between early-onset CRC and BRAF (0.77, 0.64-0.92) and APC mutation (0.81, 0.67-0.97) were attenuated, while an inverse association with PIK3CA mutation was also observed (0.88, 0.78-0.99). Early-onset tumors are less likely to develop along the CpG Island Methylator Phenotype pathway (0.24, 0.10-0.57), but more likely to possess adverse histological features including high tumor grade (1.20, 1.15-1.25), and mucinous (1.22, 1.16-1.27) or signet ring histology (2.32, 2.08-2.57). A positive association with MSI status (1.31, 1.11-1.56) was also identified. Associations with immune markers and the consensus molecular subtypes are inconsistent.

Discussion

A lower prevalence of mutations in KRAS and BRAF is consistent with extended survival and superior response to targeted therapies for metastatic disease. Conversely, early-onset CRC is associated with aggressive histological subtypes and TP53 and PTEN mutations, which may serve as therapeutic targets.

Distinct Driver Pathway Enrichments and a High Prevalence of TSC2 Mutations in Right Colon Cancer in Chile: A Preliminary Comparative Analysis

Colorectal cancer (CRC) is the second leading cause of cancer deaths globally. While ethnic differences in driver gene mutations have been documented, the South American population remains understudied at the genomic level, despite facing a rising burden of CRC. We analyzed tumors of 40 Chilean CRC patients (Chp) using next-generation sequencing and compared them to data from mainly Caucasian cohorts (TCGA and MSK-IMPACT). We identified 388 mutations in 96 out of 135 genes, with TP53 (45%), KRAS (30%), PIK3CA (22.5%), ATM (20%), and POLE (20%) being the most frequently mutated. TSC2 mutations were associated with right colon cancer (44.44% in RCRC vs. 6.45% in LCRC, p-value = 0.016), and overall frequency was higher compared to TCGA (p-value = 1.847 × 10-5) and MSK-IMPACT cohorts (p-value = 3.062 × 10-2). Limited sample size restricts definitive conclusions, but our data suggest potential differences in driver mutations for Chilean patients, being that the RTK-RAS oncogenic pathway is less affected and the PI3K pathway is more altered in Chp compared to TCGA (45% vs. 25.56%, respectively). The prevalence of actionable pathways and driver mutations can guide therapeutic choices, but can also impact treatment effectiveness. Thus, these findings warrant further investigation in larger Chilean cohorts to confirm these initial observations. Understanding population-specific driver mutations can guide the development of precision medicine programs for CRC patients.

Genomic landscape of diploid and aneuploid microsatellite stable early onset colorectal cancer

Although colorectal cancer (CRC) remains the second leading cause of cancer-related death in the United States, the overall incidence and mortality from the disease have declined in recent decades. In contrast, there has been a steady increase in the incidence of CRC in individuals under 50 years of age. Hereditary syndromes contribute disproportionately to early onset CRC (EOCRC). These include microsatellite instability high (MSI+) tumors arising in patients with Lynch Syndrome. However, most EOCRCs are not associated with familial syndromes or MSI+ genotypes. Comprehensive genomic profiling has provided the basis of improved more personalized treatments for older CRC patients. However, less is known about the basis of sporadic EOCRC. To define the genomic landscape of EOCRC we used DNA content flow sorting to isolate diploid and aneuploid tumor fractions from 21 non-hereditary cases. We then generated whole exome mutational profiles for each case and whole genome copy number, telomere length, and EGFR immunohistochemistry (IHC) analyses on subsets of samples. These results discriminate the molecular features of diploid and aneuploid EOCRC and provide a basis for larger population-based studies and the development of effective strategies to monitor and treat this emerging disease.

MAFLD with central obesity is associated with increased risk of colorectal adenoma and high-risk adenoma

OBJECTIVE

To analyze the risk factors associated with colorectal adenoma and to investigate the associations of metabolism-related fatty liver disease (MAFLD) with obesity, colorectal adenoma and high-risk adenoma.

METHODS

A total of 1395 subjects were enrolled and divided into a colorectal adenoma group (593 subjects) and a control group (802 subjects) according to the inclusion and exclusion criteria. The characteristics of patients in the colorectal adenoma group and the control group were compared by the chi-square test. Univariate and multivariate logistic analyses were used to analyze independent risk factors and associations with different MAFLD subtypes. Colorectal adenoma characteristics and the proportion of patients with high-risk colorectal adenoma were also compared.

RESULTS

High-density lipoprotein (HDL-C) was significantly lower in patients in the colorectal adenoma group than in those in the control group (P < 0.001). Logistic regression analysis revealed that age, obesity status, central obesity status, hypertension status, diabetes status, fatty liver status, smoking history, BMI, waist circumference, triglyceride level, HDL-C level, fasting blood glucose level and degree of hepatic steatosis were all independent risk factors for colorectal adenoma. Notably, MAFLD was associated with a significantly increased risk of colorectal adenoma in patients with central obesity (P < 0.001). In addition, obesity, central obesity, diabetes, fatty liver and degree of hepatic steatosis were all shown to be independent risk factors for high-risk colorectal adenoma. In addition, a greater proportion of MAFLD patients with central obesity than those without central obesity had high-risk colorectal adenoma.

CONCLUSION

MAFLD and central obesity are independently associated with the development of colorectal adenoma. MAFLD with central obesity is associated with an increased risk of colorectal adenoma and high-risk adenoma.

The microbial landscape of colorectal cancer

Colorectal cancer (CRC) is a substantial source of global morbidity and mortality in dire need of improved prevention and treatment strategies. As our understanding of CRC grows, it is becoming increasingly evident that the gut microbiota, consisting of trillions of microorganisms in direct interface with the colon, plays a substantial role in CRC development and progression. Understanding the roles that individual microorganisms and complex microbial communities play in CRC pathogenesis, along with their attendant mechanisms, will help yield novel preventive and therapeutic interventions for CRC. In this Review, we discuss recent evidence concerning global perturbations of the gut microbiota in CRC, associations of specific microorganisms with CRC, the underlying mechanisms by which microorganisms potentially drive CRC development and the roles of complex microbial communities in CRC pathogenesis. While our understanding of the relationship between the microbiota and CRC has improved in recent years, our findings highlight substantial gaps in current research that need to be filled before this knowledge can be used to the benefit of patients.

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.

Label-free quantification of imaging features in the extracellular matrix of left and right-sided colon cancer tissues

The molecular pathogenesis of colorectal cancer is known to differ between the right and left side of the colon. Several previous studies have focussed on the differences in clinicopathological features, proteomic and genetic biomarkers, the composition of gut microbiota, response to therapy, and the characteristics of the tumour microenvironment. However, the morphology and density of collagen in the extracellular matrix (ECM) have not been studied intensively. In this study, we employed 2-photon laser scanning microscopy (2PLSM) to visualise the intrinsic second-harmonic generation (SHG) signal emitted by collagen fibres in the heterogeneous ECM of human colon tumour tissues. Through texture analysis of the SHG signal, we quantitatively distinguished the imaging features generated by structural differences of collagen fibres in healthy colon and cancers and found marked differences. The fibres inside of tumours exhibited a loss of organisation, particularly pronounced in right-sided colon cancer (RSCC), where the chaotic regions were significantly increased. In addition, a higher collagen content was found in left-sided colon cancer (LSCC). In future, this might aid in subclassification and therapeutic decisions or even in designing new therapy regimens by taking into account the differences between collagen fibres features between colon tumours located at different sides.

Colorectal cancer disease profile and treatment patterns at an urban tertiary hospital in Rwanda

Background

The incidence of colorectal cancer (CRC) in sub-Saharan Africa (SSA) is rising, due to improving cancer registration efforts on one hand and an increasing westernisation of diets and lifestyle on the other as well as increasing rates of comorbidities.

Methods

We present data for the clinical characteristics, pathology, treatments received, and survival outcomes of patients diagnosed with CRC at King Faisal Hospital (KFH) between January 2019 and May 2023. KFH is an urban tertiary hospital in Rwanda that provides chemotherapy and surgery to cancer patients. The data were extracted from electronic medical records, imaging and histopathology reports from the patient's time of diagnosis. We plotted Kaplan-Meier estimation of survival, defined as the time from presentation to death, within the study period (2019-2023).

Results

Seventy-four patients diagnosed with CRC with complete information were identified in the KFH oncology records. The mean age at diagnosis was 54.6 years, with ages ranging between 22 and 81 years. At diagnosis, 24 (32.4%) patients were less than 50 years old and 29 (39.2%) were females. The rectum (36.5%) was the most common tumour location, and 58.1 tumours were left-sided. Most patients presented with Stage III (41.9%) or IV (35.1%) disease. Adenocarcinoma was the most common histological type (98.6%) including adenocarcinoma not otherwise specified (NOS) (86.5%), mucinous adenocarcinoma (10.8%), signet ring cell carcinoma (1.4%) and followed by squamous cell carcinoma (1.4%). In terms of treatment, 19 (25.7%) patients received only chemotherapy, 43 (58.1%) patients received neo-adjuvant or adjuvant chemotherapy, 9 (12.2%) of patients received both neo-adjuvant and adjuvant chemotherapy, 49 patients (66.2%) underwent surgery and 17 (23%) patients also received radiation. At the end of the follow up period, 63 (85.1%) patients remained in surveillance, 10 (13.5%) patients died, and 1 (1.3%) patient was lost to follow up. Mean overall survival was 45.5 (SD ± 2.0) months.

Conclusion

CRC patients presented at an advanced stage and required complex treatment regimens at KFH. Further epidemiologic and molecular research is needed to characterise CRC incidence and presentation at a national level in Rwanda as increasing westernisation continues to change the face of CRC in urban areas of SSA.

Diverging likelihood of colon and rectal cancer in Yogyakarta, Indonesia: A cross sectional study

OBJECTIVES

Colon and rectal cancer are associated with different risk factors and prognostic. However, this discrepancy has not been widely explored in the local population. This study aimed to investigate the site-specific likelihood of colorectal cancer (CRC) incidence in the Yogyakarta province, Indonesia.

METHODS

This cross-sectional study analyses 1,295 CRC cases diagnosed in 2008-2019 registered in the Yogyakarta population-based cancer registry (PBCR) database. Cases were grouped into colon and rectal cancer. Log-binomial regression was used to determine the relative risk of either colon or rectal cancer across different gender, age group, and rurality of residence. The age-specific rates were calculated by age group and temporal trend for each group were analyzed using joinpoint regression.

RESULTS

Females displayed higher odds of colon cancer (relative risk/RR = 1.20, 95%CI = 1.02-1.41) and lower odds of rectal cancer (RR = 0.92, 95%CI = 0.85-0.99). Elevated odds of colon cancer were observed in younger age group, especially 30-39 (RR = 1.87, 95%CI = 1.10-3.19), while decreased odds of rectal cancer was apparent in age group 30-39 and 40-49 (RR = 0.75, 95%CI = 0.60-0.93 and RR = 0.82, 95%CI = 0.69-0.98, respectively). Living in urban or rural areas did not significantly influence the odds of either having colon (RR = 0.98, 95%CI = 0.82-1.17) or rectal cancer (RR = 1.01, 95%CI = 0.93-1.10). During 2008-2019, trends of colon cancer in age <50 increased by 8.15% annually while rectal cancer displayed a 9.71% increase annually prior to 2017, followed by a 17.23% decrease until 2019.

CONCLUSIONS

Yogyakarta population shows higher odds of young-onset colon cancer, especially between age 30-39 years old. Overall observation of trend shows increasing incidence in young-onset colon cancer, and non-significant decrease in rectal cancer.

scRNA-seq of colorectal cancer shows regional immune atlas with the function of CD20+ B cells

Colorectal cancer (CRC) from different regions exhibits different histological, genetic characteristics, and molecular subtypes, even in response to conventional chemotherapies and immunotherapies. To characterize the immune landscape in different regions of CRC and search for potential therapeutic targets, we analyzed 39,484 single-cell transcription data from 19 samples of CRC and paired normal tissues from four regions to identify the immune characteristics of CRC among anatomic locations, especially in B cells. We discovered that immune cell infiltration in tumors significantly varied among different regions of CRC. B cells from right- and left-sided CRC had different development trajectories, but both had extensive interactions with myeloid cells and T cells. Survival analysis suggested that CD20+ B cells correlated with good prognosis in CRC patients, especially on the right side. Furthermore, the depletion of CD20+ B cells demonstrated that anti-CD20 promoted tumor growth progression and reversed the tumor-killing activity of anti-PD-1 treatment in vivo and in vitro. Our results highlight the characterization of the immune landscape of CRC in different regions. CD20+ B-cell infiltration has been associated with CRC patient prognosis and may promote the tumor-killing role of PD-1 antibodies.

Long-term Outcomes of Robot-assisted Versus Laparoscopic Surgery for Colon Cancer: A Nationwide Register-based Cohort Study

OBJECTIVE

To determine long-term survival in patients undergoing robot-assisted surgery (RAS) or laparoscopic surgery (LAS) for colon cancer.

BACKGROUND

The potential long-term benefits of RAS compared with LAS for colon cancer are not well examined. Using a register-based approach, we aimed to compare these 2 surgical platforms in an analysis of long-term outcomes, including recurrence-free survival and all-cause- and colon cancer-specific mortality.

METHODS

A nationwide register-based cohort study of patients with Union for International Cancer Control stage I-III colon cancer undergoing planned RAS or LAS from 2010 through 2018. Patient demographic, clinical, and pathological data were retrieved from Danish national registers. Survival and recurrence rates were estimated by Cox proportional hazard multivariate regression analysis adjusting for baseline covariates.

RESULTS

A total of 7565 patients [LAS=6905 (91%) and RAS=660 (9%)] were included in the complete case survival analysis. Patients undergoing LAS had a significantly increased risk of cancer recurrence [LAS=1178 (17.1%), RAS=82 (12.4%), P =0.002] with a mean follow-up time of 4.93 years (standard deviation 2.47). The survival analysis of recurrence-free survival favored RAS [hazard ratio adjusted =0.80, 95% CI (0.64-1.00), P =0.049]. No associations between the 2 surgical platforms were evident regarding all-cause [hazard ratio adjusted =0.98, 95% CI (0.82-1.17), P =0.783] or colon cancer-specific mortality [hazard ratio adjusted =0.89, 95% CI (0.67-1.18), P =0.405].

CONCLUSIONS

Adopting RAS for colon cancer was associated with improved recurrence-free survival. However, it did not cause a lower all-cause- or colon cancer-specific mortality.

The Safety and Effectiveness of Bevacizumab in Metastatic Colorectal Cancer With Unresectable Metastases: A Real-Life Study From the South of Morocco

Background Colorectal cancer constitutes a significant public health challenge, despite remarkable strides made in the last two decades, particularly in the medical management of metastatic stages. Notable progress has been achieved through targeted therapies such as anti-epidermal growth factor receptors or anti-angiogenic antibodies, as well as advancements in surgical approaches for hepatic metastases. This study seeks to assess the efficacy and safety of bevacizumab plus chemotherapy in individuals with metastatic colorectal cancer. Methodology This is an observational, cross-sectional, retrospective study of all patients who were followed up for metastatic colorectal cancer with unresectable metastases and were treated with bevacizumab in combination with standard chemotherapy from January 2010 until December 2019 in the medical oncology department of the Centre Hospitalier Universitaire (CHU) Souss-Massa of Agadir. Results Of the total 162 cases, 117 (72%) had metastatic disease, and 45 (28%) progressed to metastatic disease after initial treatment. The median age of the patients was 55 years (range = 23-79 years) with a sex ratio of 1.1 (M/F). The tumor was located in the left colon in 135 (83.3%) patients. The results represented adenocarcinoma in 137 (84.6) cases and mucinous subtype in 23 (14.19) cases. The three most common sites of metastasis were the liver (99, 61.1), peritoneum (67, 41.3), and lung (33, 20.3). In the first line, all patients received bi-chemotherapy plus bevacizumab, i.e., fluorouracil, oxaliplatin, and leucovorin in 34 (20.9%) patients; capecitabine plus oxaliplatin in 88 (54.3%) patients; leucovorin, fluorouracil, and irinotecan in 17 (10.4%) patients; and capecitabine plus irinotecan in 23 (14.1%) patients. Response after first-line treatment was progression in 74 (45.7) cases, stability in 42 (25.9) cases, partial response in 35 (21.6) cases, and complete response in 11 (6.8) cases. Nine (6%) patients were able to benefit from surgical resection of metastatic lesions. Overall, 77 (47%) patients received second-line chemotherapy, i.e., 5-FU with irinotecan in 40 (51.8%) cases or with oxaliplatin in 30 (38.8%) cases. Two patients developed undesirable side effects under bevacizumab (hypertension). The median progression-free survival and median overall survival of the study cohort were 9 months and 14 months, respectively. Nevertheless, patients who underwent primary tumor resection (p = 0.048), those with right‑sided tumors (p = 0.022), those who received a higher number of treatment cycles (p = 0.020), and those who received maintenance treatment (p = 0.001) had a longer median overall survival. Conclusions Chemotherapy combination with bevacizumab is considered as the cornerstone of metastatic colorectal cancer treatment in our region. With the new healthcare and social security systems, easier access to expensive treatments and molecular pathology tests is currently available. It is important to highlight that real-world data can offer valuable insights into the daily clinical practice of medical oncology.

Proteogenomic characterization of primary colorectal cancer and metastatic progression identifies proteome-based subtypes and signatures

Metastatic progression of colorectal adenocarcinoma (CRC) remains poorly understood and poses significant challenges for treatment. To overcome these challenges, we performed multiomics analyses of primary CRC and liver metastases. Genomic alterations, such as structural variants or copy number alterations, were enriched in oncogenes and tumor suppressor genes and increased in metastases. Unsupervised mass spectrometry-based proteomics of 135 primary and 123 metastatic CRCs uncovered distinct proteomic subtypes, three each for primary and metastatic CRCs, respectively. Integrated analyses revealed that hypoxia, stemness, and immune signatures characterize these 6 subtypes. Hypoxic CRC harbors high epithelial-to-mesenchymal transition features and metabolic adaptation. CRC with a stemness signature shows high oncogenic pathway activation and alternative telomere lengthening (ALT) phenotype, especially in metastatic lesions. Tumor microenvironment analysis shows immune evasion via modulation of major histocompatibility complex (MHC) class I/II and antigen processing pathways. This study characterizes both primary and metastatic CRCs and provides a large proteogenomics dataset of metastatic progression.

Tumor location matters, next generation sequencing mutation profiling of left-sided, rectal, and right-sided colorectal tumors in 552 patients

Despite the introduction of new molecular classifications, advanced colorectal cancer (CRC) is treated with chemotherapy supplemented with anti-EGFR and anti-VEGF targeted therapy. In this study, 552 CRC cases with different primary tumor locations (250 left side, 190 rectum, and 112 right side) were retrospectively analyzed by next generation sequencing for mutations in 50 genes. The most frequently mutated genes were TP53 in left-sided tumors compared to right-sided tumors and BRAF in right-sided tumors compared to left-sided tumors. Mutations in KRAS, NRAS, and BRAF were not detected in 45% of patients with left-sided tumors and in 28.6% of patients with right-sided tumors. Liver metastases were more common in patients with left-sided tumors. Tumors on the right side were larger at diagnosis and had a higher grade (G3) than tumors on the left. Rectal tumors exhibit distinctive biological characteristics when compared to left-sided tumors, including a higher absence rate of KRAS, NRAS, and BRAF mutations (47.4% in rectal versus 42.8% in left-sided tumors). These rectal tumors are also unique in their primary metastasis site, which is predominantly the lungs, and they have varying mutation rates, particularly in genes such as BRAF, FBXW7, and TP53, that distinguish them from tumors found in other locations. Primary tumor location has implications for the potential treatment of CRC with anti-EGFR therapy.

NOS2 Polymorphism in Aspect of Left and Right-Sided Colorectal Cancer

Background: The NOS2 gene polymorphism rs2297518 is associated with an increased level of NO, which could contribute to colorectal cancer (CRC) development. We hypothesized that the potential influence of the NOS2 gene polymorphism on cancer development may vary between right-sided and left-sided colon cancers, and rectal cancers. The aim of this study was to determine the rs2297518 polymorphism influence on colorectal cancer development with regard to tumor localization. Methods: This case-control study included 199 patients with CRC and 120 controls. The qPCR endpoint genotyping was conducted using the TaqMan® genotyping assay. Results: This study revealed significant differences in tumor characteristic and in the minor alelle A frequency in the NOS2 genotype between colorectal cancers with different localizations. The mucinous adenocarcinoma was diagnosed significantly more often in right-sided cancers than in left-sided (30.6% vs. 10.9%, p = 0.009) and rectal cancers (30.6% vs. 7.1%, p = 0.0003). The minor allele A of the NOS2 genotype was observed more frequently in right-sided cancers than in left-sided cancers (44.9% vs. 23.1%, p = 0.0137) and more frequently in rectal cancers than in left-sided cancers (40.0% vs. 23.1%, p = 0.0285). Conclusions: In conclusion, the results support the hypothesis that the SNP rs2297518 of the NOS2 gene influences colorectal cancer development with regard to tumor localization.

Stratification of Colorectal Patients Based on Survival Analysis Shows the Value of Consensus Molecular Subtypes and Reveals the CBLL1 Gene as a Biomarker of CMS2 Tumours

The consensus molecular subtypes (CMSs) classification of colorectal cancer (CRC) is a system for patient stratification that can be potentially applied to therapeutic decisions. Hakai (CBLL1) is an E3 ubiquitin-ligase that induces the ubiquitination and degradation of E-cadherin, inducing epithelial-to-mesenchymal transition (EMT), tumour progression and metastasis. Using bioinformatic methods, we have analysed CBLL1 expression on a large integrated cohort of primary tumour samples from CRC patients. The cohort included survival data and was divided into consensus molecular subtypes. Colon cancer tumourspheres were used to analyse the expression of stem cancer cells markers via RT-PCR and Western blotting. We show that CBLL1 gene expression is specifically associated with canonical subtype CMS2. WNT target genes LGR5 and c-MYC show a similar association with CMS2 as CBLL1. These mRNA levels are highly upregulated in cancer tumourspheres, while CBLL1 silencing shows a clear reduction in tumoursphere size and in stem cell biomarkers. Importantly, CMS2 patients with high CBLL1 expression displayed worse overall survival (OS), which is similar to that associated with CMS4 tumours. Our findings reveal CBLL1 as a specific biomarker for CMS2 and the potential of using CMS2 with high CBLL1 expression to stratify patients with poor OS.

Update on Targeted Therapy and Immunotherapy for Metastatic Colorectal Cancer

Metastatic colorectal cancer remains a deadly malignancy and is the third leading cause of cancer-related death. The mainstay of treatment for metastatic colorectal cancer is chemotherapy, but unfortunately, even with recent progress, overall survival is still poor. Colorectal cancer is a heterogeneous disease, and the underlying genetic differences among tumors can define the behavior and prognosis of the disease. Given the limitations of cytotoxic chemotherapy, research has focused on developing targeted therapy based on molecular subtyping. Since the early 2000s, multiple targeted therapies have demonstrated efficacy in treating metastatic colorectal cancer and have received FDA approval. The epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and DNA mismatch repair pathways have demonstrated promising results for targeted therapies. As new gene mutations and proteins involved in the oncogenesis of metastatic colorectal cancer are identified, new targets will continue to emerge. We herein provide a summary of the updated literature regarding targeted therapies for patients with mCRC.

A Randomized Phase III Study of Arfolitixorin versus Leucovorin with 5-Fluorouracil, Oxaliplatin, and Bevacizumab for First-Line Treatment of Metastatic Colorectal Cancer: The AGENT Trial

PURPOSE

Suboptimal treatment outcomes with 5-fluorouracil (5-FU)/folate, the standard of care for metastatic colorectal cancer (mCRC), have generated interest in optimizing the folate. Arfolitixorin ([6R]-5,10-methylene-tetrahydrofolate) is an immediately active folate and may improve outcomes over the existing standard of care (leucovorin).

EXPERIMENTAL DESIGN

AGENT was a randomized, phase III study (NCT03750786). Patients with mCRC were randomized to arfolitixorin (120 mg/m2 given as two intravenous bolus doses of 60 mg/m2) or leucovorin (400 mg/m2 given as a single intravenous infusion) plus 5-FU, oxaliplatin, and bevacizumab. Assessments were performed every 8 weeks. The primary endpoint was the superiority of arfolitixorin for overall response rate (ORR).

RESULTS

Between February 2019 and April 2021, 490 patients were randomized (245 to each arm). After a median follow-up of 266 days, the primary endpoint of superiority for ORR was not achieved (48.2% for arfolitixorin vs. 49.4% for leucovorin, Psuperiority = 0.57). Outcomes were not achieved for median progression-free survival (PFS; 12.8 and 11.6 months, P = 0.38), median duration of response (12.2 and 12.9 months, P = 0.40), and median overall survival (23.8 and 28.0 months, P = 0.78). The proportion of patients with an adverse event of grade ≥3 severity was similar between arms (68.7% and 67.2%, respectively), as was quality of life. BRAF mutations and MTHFD2 expression were both associated with a lower PFS with arfolitixorin.

CONCLUSIONS

The study failed to demonstrate clinical benefit of arfolitixorin (120 mg/m2) over leucovorin. However, it provides some useful insights from the first-line treatment setting, including the effect of gene expression on outcomes.

SIGNIFICANCE

This phase III study compared arfolitixorin, a direct-acting folate, with leucovorin in FOLFOX plus bevacizumab in mCRC. Arfolitixorin (120 mg/m2) did not improve the ORR, potentially indicating a suboptimal dose.

A Practical Approach to Interpreting Circulating Tumor DNA in the Management of Gastrointestinal Cancers

BACKGROUND

There is accumulating evidence supporting the clinical use of circulating tumor DNA (ctDNA) in solid tumors, especially in different types of gastrointestinal cancer. As such, appraisal of the current and potential clinical utility of ctDNA is needed to guide clinicians in decision-making to facilitate its general applicability.

CONTENT

In this review, we firstly discuss considerations surrounding specimen collection, processing, storage, and analysis, which affect reporting and interpretation of results. Secondly, we evaluate a selection of studies on colorectal, esophago-gastric, and pancreatic cancer to determine the level of evidence for the use of ctDNA in disease screening, detection of molecular residual disease (MRD) and disease recurrence during surveillance, assessment of therapy response, and guiding targeted therapy. Lastly, we highlight current limitations in the clinical utility of ctDNA and future directions.

SUMMARY

Current evidence of ctDNA in gastrointestinal cancer is promising but varies depending on its specific clinical role and cancer type. Larger prospective trials are needed to validate different aspects of ctDNA clinical utility, and standardization of collection protocols, analytical assays, and reporting guidelines should be considered to facilitate its wider applicability.

The colibactin-producing Escherichia coli alters the tumor microenvironment to immunosuppressive lipid overload facilitating colorectal cancer progression and chemoresistance

Intratumoral bacteria flexibly contribute to cellular and molecular tumor heterogeneity for supporting cancer recurrence through poorly understood mechanisms. Using spatial metabolomic profiling technologies and 16SrRNA sequencing, we herein report that right-sided colorectal tumors are predominantly populated with Colibactin-producing Escherichia coli (CoPEC) that are locally establishing a high-glycerophospholipid microenvironment with lowered immunogenicity. It coincided with a reduced infiltration of CD8+ T lymphocytes that produce the cytotoxic cytokines IFN-γ where invading bacteria have been geolocated. Mechanistically, the accumulation of lipid droplets in infected cancer cells relied on the production of colibactin as a measure to limit genotoxic stress to some extent. Such heightened phosphatidylcholine remodeling by the enzyme of the Land's cycle supplied CoPEC-infected cancer cells with sufficient energy for sustaining cell survival in response to chemotherapies. This accords with the lowered overall survival of colorectal patients at stage III-IV who were colonized by CoPEC when compared to patients at stage I-II. Accordingly, the sensitivity of CoPEC-infected cancer cells to chemotherapies was restored upon treatment with an acyl-CoA synthetase inhibitor. By contrast, such metabolic dysregulation leading to chemoresistance was not observed in human colon cancer cells that were infected with the mutant strain that did not produce colibactin (11G5∆ClbQ). This work revealed that CoPEC locally supports an energy trade-off lipid overload within tumors for lowering tumor immunogenicity. This may pave the way for improving chemoresistance and subsequently outcome of CRC patients who are colonized by CoPEC.

Mesothelin expression correlates with elevated inhibitory immune activity in patients with colorectal cancer

The expression of the protein Mesothelin (MSLN) is highly variable in several malignancies including colorectal cancer (CRC) and high levels are associated with aggressive clinicopathological features and worse patient survival. CRC is both a common and deadly cancer; being the third most common in incidence and second most common cause of cancer related death. While systemic therapy remains the primary therapeutic option for most patients with stage IV (metastatic; m) CRC, their disease eventually becomes treatment refractory, and 85% succumb within 5 years. Microsatellite-stable (MSS) CRC tumors, which affect more than 90% of patients with mCRC, are generally refractory to immunotherapeutic interventions. In our current work, we characterize MSLN levels in CRC, specifically correlating expression with clinical outcomes in relevant CRC subtypes and explore how MSLN expression impacts the status of immune activation and suppression in the peritumoral microenvironment. High MSLN expression is highly prevalent in CMS1 and CMS4 CRC subtypes as well as in mCRC tissue and correlates with higher gene mutation rates across the patient cohorts. Further, MSLN-high patients exhibit increased M1/M2 macrophage infiltration, PD-L1 staining, immune-inhibitory gene expression, enrichment in inflammatory, TGF-β, IL6/JAK/STAT3, IL2/STAT5 signaling pathways and mutation in KRAS and FBXW7. Together, these results suggest MSLN protein is a potential target for antigen-specific therapy and supports investigation into its tumorigenic effects to identify possible therapeutic interventions for patients with high MSLN expressing MSS CRC.

A predictive model for early death in elderly colorectal cancer patients: a population-based study

Purpose

The purpose of this study is to determine what variables contribute to the early death of elderly colorectal cancer patients (ECRC) and to generate predictive nomograms for this population.

Methods

This retrospective cohort analysis included elderly individuals (≥75 years old) diagnosed with colorectal cancer (CRC) from 2010-2015 in the Surveillance, Epidemiology, and End Result databases (SEER) databases. The external validation was conducted using a sample of the Chinese population obtained from the China-Japan Union Hospital of Jilin University. Logistic regression analyses were used to ascertain variables associated with early death and to develop nomograms. The nomograms were internally and externally validated with the help of the receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA).

Results

The SEER cohort consisted of 28,111 individuals, while the Chinese cohort contained 315 cases. Logistic regression analyses shown that race, marital status, tumor size, Grade, T stage, N stage, M stage, brain metastasis, liver metastasis, bone metastasis, surgery, chemotherapy, and radiotherapy were independent prognostic factors for all-cause and cancer-specific early death in ECRC patients; The variable of sex was only related to an increased risk of all-cause early death, whereas the factor of insurance status was solely associated with an increased risk of cancer-specific early death. Subsequently, two nomograms were devised to estimate the likelihood of all-cause and cancer-specific early death among individuals with ECRC. The nomograms exhibited robust predictive accuracy for predicting early death of ECRC patients, as evidenced by both internal and external validation.

Conclusion

We developed two easy-to-use nomograms to predicting the likelihood of early death in ECRC patients, which would contribute significantly to the improvement of clinical decision-making and the formulation of personalized treatment approaches for this particular population.

Sex Differences in Colon Cancer: Genomic and Nongenomic Signalling of Oestrogen

Colon cancer (CRC) is a prevalent malignancy that exhibits distinct differences in incidence, prognosis, and treatment responses between males and females. These disparities have long been attributed to hormonal differences, particularly the influence of oestrogen signalling. This review aims to provide a comprehensive analysis of recent advances in our understanding of the molecular mechanisms underlying sex differences in colon cancer and the protective role of membrane and nuclear oestrogen signalling in CRC development, progression, and therapeutic interventions. We discuss the epidemiological and molecular evidence supporting sex differences in colon cancer, followed by an exploration of the impact of oestrogen in CRC through various genomic and nongenomic signalling pathways involving membrane and nuclear oestrogen receptors. Furthermore, we examine the interplay between oestrogen receptors and other signalling pathways, in particular the Wnt/β-catenin proliferative pathway and hypoxia in shaping biological sex differences and oestrogen protective actions in colon cancer. Lastly, we highlight the potential therapeutic implications of targeting oestrogen signalling in the management of colon cancer and propose future research directions to address the current gaps in our understanding of this complex phenomenon.

Radioembolisation of liver metastases

This review aims to present contemporary data for SIRT in the treatment of secondary hepatic malignancies including colorectal, neuroendocrine, breast and uveal melanoma.

Disruptions in cell fate decisions and transformed enteroendocrine cells drive intestinal tumorigenesis in Drosophila

Most epithelial tissues are maintained by stem cells that produce the different cell lineages required for proper tissue function. Constant communication between different cell types ensures precise regulation of stem cell behavior and cell fate decisions. These cell-cell interactions are often disrupted during tumorigenesis, but mechanisms by which they are co-opted to support tumor growth in different genetic contexts are poorly understood. Here, we introduce PromoterSwitch, a genetic platform we established to generate large, transformed clones derived from individual adult Drosophila intestinal stem/progenitor cells. We show that cancer-driving genetic alterations representing common colon tumor genome landscapes disrupt cell fate decisions within transformed tissue and result in the emergence of abnormal cell fates. We also show that transformed enteroendocrine cells, a differentiated, hormone-secreting cell lineage, support tumor growth by regulating intestinal stem cell proliferation through multiple genotype-dependent mechanisms, which represent potential vulnerabilities that could be exploited for therapy.

Genetic profile of Chinese patients with small bowel cancer categorized by anatomic location

BACKGROUND

Small bowel cancer (SBC) is a very rare solid malignancy. Consequently, compared with other malignant gastrointestinal tumors, our knowledge regarding SBC, specifically its molecular attributes, remains limited. Herein, we aim to provide an overview of the gene characteristics of Chinese patients with SBC, We particularly focus on elucidating the genetic intricacies that differentiate SBC patients whose primary tumors originate in distinct anatomical regions within the small bowel.

METHODS

During the period ranging from February 2018 to December 2022, a total of 298 tumor samples were consecutively collected from Chinese patients diagnosed with small bowel cancer.. Next-generation sequencing (NGS) was performed to detect gene mutation, assess microsatellite instability (MSI), and evaluate tumor mutational burden (TMB). Additionally,, IHC was used to analyze the level of PD-L1 expression within the samples.

RESULTS

The outcomes of the next-generation sequencing (NGS) unveiled the predominant gene mutations observed in Chinese patients with small bowel cancer (SBC). The top ten gene mutations identified were as follows: TP53 (53%), KRAS (51%), APC (31%), SMAD4 (19%), VEGFA (15%), CDKN2A (15%), RAC1 (15%), LRP1B (14%), MGMT (14%, CD74 (13%). Subsequent analysis revealed disparities in the gene landscape between the cohort in this study and that of the Memorial Sloan Kettering Cancer Center (MSKCC), Notably, distinguishable mutational frequencies were identified in several genes, including ERBB2, FBXW7, PIK3CA, etc. which exhibited contrasting presence in both this cohort and the MSKCC cohort.. Furthermore, we noticed variations in the frequency of gene mutations among SBC patients depending on the specific anatomical site where the tumors originated within the small bowel. In addition, the distribution of patients with high microsatellite instability (MSI-H) and tumor mutational burden (TMB) levels varied among SBC patients with tumors originating from the duodenum, jejunum, and ileum.

CONCLUSION

Chinese patients with small bowel cancer exhibited a distinct genetic profile in comparison to other populations, highlighting a unique genetic landscape. Furthermore, noticeable disparities in the genetic landscape were observed between patients with cancer situated in the duodenum and those with cancer affecting other regions of the small bowel, this suggests that these patients should be treated differently.