Multiple-matrix metabolomics analysis for the distinct detection of colorectal cancer and adenoma.

OBJECTIVES: Although colorectal cancer (CRC) is the leading cause of cancer-related morbidity and mortality, current diagnostic tests for early-stage CRC and colorectal adenoma (CRA) are suboptimal. Therefore, there is an urgent need to explore less invasive screening procedures for CRC and CRA diagnosis. METHODS: Untargeted gas chromatography-mass spectrometry (GC-MS) metabolic profiling approach was applied to identify candidate metabolites. We performed metabolomics profiling on plasma samples from 412 subjects including 200 CRC patients, 160 CRA patients and 52 normal controls (NC). Among these patients, 45 CRC patients, 152 CRA patients and 50 normal controls had their fecal samples tested simultaneously. RESULTS: Differential metabolites were screened in the adenoma-carcinoma sequence. Three diagnostic models were further developed to identify cancer group, cancer stage, and cancer microsatellite status using those significant metabolites. The three-metabolite-only classifiers used to distinguish the cancer group always keeps the area under the receiver operating characteristic curve (AUC) greater than 0.7. The AUC performance of the classifiers applied to discriminate CRC stage is generally greater than 0.8, and the classifiers used to distinguish microsatellite status of CRC is greater than 0.9. CONCLUSION: This finding highlights potential early-driver metabolites in CRA and early-stage CRC. We also find potential metabolic markers for discriminating the microsatellite state of CRC. Our study and diagnostic model have potential applications for non-invasive CRC and CRA detection.

Association between microsatellite status and characteristics and outcomes of early-onset compared to late-onset rectal cancer.

BACKGROUND: Microsatellite instability (MSI) is an important prognosticator for colorectal cancer (CRC). The present study aimed to assess the impact of MSI status on the characteristics and outcomes of early-onset compared to late-onset rectal cancer. METHODS: This retrospective cohort study used data from the US National Cancer Database (2004-2019) to assess the baseline characteristics, treatment patterns, short-term outcomes, and overall survival (OS) of early-onset rectal adenocarcinoma affecting patients < 50 years compared to late-onset rectal adenocarcinoma according to the MSI status. RESULTS: The present study included 48,407 patients (59.9% male) with rectal cancer, 17.3% of patients were < 50 years and 6.3% had MSI-H tumors. In the early-onset group, patients with MSI-H tumors had a lower mean age (41.5 vs 43 years, p < 0.001) and presented less often with stage IV disease (22.1% vs 17.7%, p = 0.03) and liver metastasis (9.1% vs 13.5%, p = 0.011) than patients with MSS tumors. In the late-onset group, patients with MSI-H and MSS tumors had similar demographics, disease stage, and metastatic pattern, yet MSI-H patients more often received neoadjuvant radiation therapy (58.9% vs 55.1%, p = 0.009) and neoadjuvant systemic therapy (40% vs 36.2%, p = 0.005). In both age groups, MSI-H tumors were associated with more pathologic T3-4 stage and were more likely mucinous and poorly differentiated carcinomas than MSS tumors. The median OS of MSI-H tumors was similar to MSS tumors (108.09 vs 102.31 months, p = 0.1), whether in the early-onset (139.5 vs 134.2 months, p = 0.821) or late-onset groups (106.1 vs 104.3 months, p = 0.236). CONCLUSIONS: In both age groups, MSI-H rectal cancers were more often mucinous and poorly differentiated carcinomas and had pT3-4 stage more often than MSS cancers. MSI-H rectal cancers tend to present less often with distant metastases and nodal involvement than MSS cancers only in early-onset, but not in late-onset rectal cancers. The association between MSI status and survival was not notable in this study, whether in the early-onset or late-onset groups.

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.

Construction of a novel methylation-related prognostic model for colorectal cancer based on microsatellite status.

The present study aimed to construct a novel methylation-related prognostic model based on microsatellite status that may enhance the prognosis of colorectal cancer (CRC) from methylation and microsatellite status perspective. DNA methylation and mRNA expression data with clinical information were downloaded from The Cancer Genome Atlas (TCGA) data set. The samples were divided into microsatellite stability and microsatellite instability group, and CIBERSORT was used to assess the immune cell infiltration characteristics. After identifying the differentially methylated genes and differentially expression genes using R packages, the methylation-driven genes were further identified. Prognostic genes that were used to establish the methylation-related risk score model were generated by the univariate and multivariate Cox regression model. Finally, we established and evaluated the methylation-related prognostic model for CRC patients. A total of 69 MDGs were obtained and three of these genes (MIOX, TH, DKFZP434K028) were selected to construct the prognostic model. Patients in the low-risk score group had a conspicuously better overall survival than those in the high-risk score group (p < .0001). The area under the receiver operating characteristic curve for this model was 0.689 at 3 years, 0.674 at 4 years, and 0.658 at 5 years. The Wilcoxon test showed that higher risk score was associated with higher T stage (p = .01), N stages (p = .0028), metastasis (p = .013), and advanced pathological stage (p = .0013). However, the more instability of microsatellite status, the lower risk score of CRC patients (p = .0048). Our constructed methylation-related prognostic model based on microsatellite status presents potential significance in assessing recurrence risk stratification, tumor staging, and immunotherapy for CRC patients.

Does Side Really Matter? Survival Analysis among Patients with Right- Versus Left-Sided Colon Cancer: A Propensity Score-Adjusted Analysis.

BACKGROUND: Right- and left-sided colon cancer are increasingly regarded as two independent disease entities based on different gene expression profiles as well as underlying genetic mutations. Data regarding prognosis and survival are heterogeneous and more favorable in cases of left-sided colon cancer. OBJECTIVE: The purpose of this study was to evaluate the long-term oncological outcome for patients with left-sided versus right-sided stage I-III colon cancer. METHODS: Overall, 318 consecutive patients who underwent surgery for right- or left-sided sided colon cancer between 2001 and 2014 were analyzed. Analysis was performed applying a prospectively maintained database with respect to overall, disease-specific, and relative survival, using Cox regression and propensity score analyses. RESULTS: A total of 155 patients (48.7%) presented with right-sided colon cancer and 163 patients (51.3%) presented with left-sided colon cancer. In risk-adjusted Cox regression analysis, tumor location had no significant impact on overall survival (hazard ratio [HR] 1.53, 95% confidence interval [CI] 0.80-2.92; p = 0.197), disease-specific survival (HR 1.36, 95% CI 0.76-2.44; p = 0.301), and relative survival (HR 1.70, 95% CI 0.89-3.27; p = 0.107). After propensity score matching, the results from risk-adjusted Cox regression analysis were confirmed. Stratified by American Joint Committee on Cancer stage, patients with right-sided stage II colon cancer had a statistically significant superior relative survival compared with patents with left-sided colon cancer. CONCLUSIONS: No significant negative impact on overall, disease-specific, or relative survival could be observed in patients with right- versus left-sided colon cancer after risk adjustment, using multivariable Cox regression and propensity score analyses.

Microsatellite Instability and Effectiveness of Adjuvant Treatment in pT1N1 Gastric Cancer: A Multicohort Study.

BACKGROUND: Microsatellite status is a prognostic biomarker in advanced gastric cancer. This retrospective study aimed to investigate the usefulness of microsatellite status in predicting prognosis and response to adjuvant treatment in pT1N1 gastric cancer. PATIENTS AND METHODS: Among 875 patients who underwent radical gastrectomy for pT1N1 gastric cancer at two tertiary hospitals, 838 with available microsatellite instability (MSI) data were included and classified into two groups according to microsatellite status: microsatellite stable (MSS) and MSI-high (MSI-H). Recurrence-free survival rate and risk factors for tumor recurrence were analyzed. RESULTS: Of 838 gastric cancer patients, 100 (11.9%) were MSI-H and 307 (36.6%) received adjuvant treatment. During median follow-up of 70 months, 42 (5.0%) patients experienced gastric cancer recurrence; hematogenous recurrences were the most common (45.2%). Recurrence-free survival was similar in the MSS and MSI-H groups (p = 0.27), and adjuvant treatment did not show an oncological benefit over surgery alone for pT1N1 gastric cancer (p = 0.53). On univariate analysis, age, operation period, and Lauren classification were significantly associated with tumor recurrence, while adjuvant treatment and MSI status were not associated with tumor recurrence. On multivariate analysis, MSI status was not associated with tumor recurrence, and adjuvant treatment worsened the tumor recurrence risk [hazard ratio (HR) 2.373, 95% confidence interval (CI) 1.125-5.006, p = 0.023). CONCLUSION: MSI status may not be a prognostic factor for tumor recurrence or a predictor of response to adjuvant treatment in pT1N1 gastric cancer patients. Considering that the effect of adjuvant treatment to decrease the risk of tumor recurrence is not clear, it may not be indicated in pT1N1 patients.

Relationship between microsatellite status and immune microenvironment of colorectal cancer and its application to diagnosis and treatment.

Due to advances in understanding the immune microenvironment of colorectal cancer (CRC), microsatellite classification (dMMR/MSI-H and pMMR/MSS) has become a key biomarker for the diagnosis and treatment of CRC patients and therefore has important clinical value. Microsatellite status is associated with a variety of clinicopathological features and affects drug resistance and the prognosis of patients. CRC patients with different microsatellite statuses have different compositions and distributions of immune cells and cytokines within their tumor microenvironments (TMEs). Therefore, there is great interest in reversing or reshaping CRC TMEs to transform immune tolerant "cold" tumors into immune sensitive "hot" tumors. This requires a thorough understanding of differences in the immune microenvironments of MSI-H and MSS type tumors. This review focuses on the relationship between CRC microsatellite status and the immune microenvironment. It focuses on how this relationship has value for clinical application in diagnosis and treatment, as well as exploring the limitations of its current application.

AtezoTRIBE: a randomised phase II study of FOLFOXIRI plus bevacizumab alone or in combination with atezolizumab as initial therapy for patients with unresectable metastatic colorectal cancer.

BACKGROUND: Immune checkpoint inhibitors (ICIs) reported remarkable achievements in several solid tumours. However, in metastatic colorectal cancer (mCRC) promising results are limited to patients with deficient mismatch repair/microsatellite instability-high (dMMR/MSI-high) tumours due to their immune-enriched microenvironment. Combining cytotoxic agents and bevacizumab in mCRC with proficient mismatch repair/microsatellite stability (pMMR/MSS) could make ICIs efficacious by increasing the exposure of neoantigens, especially with highly active chemotherapy regimens, inducing immunogenic cell death, increasing the tumoral infiltration of CD8+ T-cells and reducing tumour-associated myeloid-derived suppressor cells. VEGF-blockade also plays an immunomodulatory role by inhibiting the expansion of T regulatory lymphocytes. Consistently with this rationale, a phase Ib study combined the anti-PDL-1 atezolizumab with FOLFOX/bevacizumab as first-line treatment of mCRC, irrespective of microsatellite status, and reported interesting activity and efficacy results, without safety concerns. Phase III trials led to identify FOLFOXIRI plus bevacizumab as an upfront therapeutic option in selected mCRC patients. Drawing from these considerations, the combination of atezolizumab with an intensified upfront treatment (FOLFOXIRI) and bevacizumab could be worthy of investigation. METHODS: AtezoTRIBE is a prospective, open label, phase II, comparative trial in which initially unresectable and previously untreated mCRC patients, irrespective of microsatellite status, are randomized in a 1:2 ratio to receive up to 8 cycles of FOLFOXIRI/bevacizumab alone or in combination with atezolizumab, followed by maintenance with bevacizumab plus 5-fluoruracil/leucovorin with or without atezolizumab according to treatment arm until disease progression. The primary endpoint is PFS. Assuming a median PFS of 12 months for standard arm, 201 patients should be randomized in a 1:2 ratio to detect a hazard ratio of 0.66 in favour of the experimental arm. A safety run-in phase including the first 6 patients enrolled in the FOLFOXIRI/bevacizumab/atezolizumab arm was planned, and no unexpected adverse events or severe toxicities were highlighted by the Safety Monitoring Committee. DISCUSSION: The AtezoTRIBE study aims at assessing whether the addition of atezolizumab to an intensified chemotherapy plus bevacizumab might be an efficacious upfront strategy for the treatment of mCRC, irrespective of the microsatellite status. TRIAL REGISTRATION: AtezoTRIBE is registered at Clinicaltrials.gov ( NCT03721653 ), October 26th, 2018 and at EUDRACT (2017-000977-35), Februray 28th, 2017.

Prognostic relevance of programmed death-ligand 1 expression and microsatellite status in small bowel adenocarcinoma.

Background: Small bowel adenocarcinoma (SBA) is a dreadful disease. Patient prognosis is limited due to late presentation and ineffective chemotherapy. PD-1/PD-L1 checkpoint immunotherapy is regarded as a promising approach in several cancer entities. The association of PD-1/PD-L1 expression and its impact on patient prognosis with SBA is unclear. Material and methods: Seventy-five consecutive patients who underwent surgery for SBA were retrospectively analyzed and stained for PD-L1 expression in the tumour or the stroma. Analysis of mismatch repair genes was performed to determine microsatellite status. Kaplan-Meier estimate was used to analyze patient survival. Univariate and multivariable Cox regression-analyses were used to assess the impact of PD-L1 expression and microsatellite status on patient survival.Results: PD-L1 was weakly upregulated within the tumour or the stroma and associated with prolonged survival (p = .0071 and p = .0472, respectively). Fifty-one tumours (68%) revealed microsatellite stability (MSS) and 24 tumours (32%) were microsatellite instable (MSI) without correlating with patient survival (p = .611). Neither PD-L1 expression in the tumour nor in the stroma was identified as an independent risk factor influencing survival (p = .572 and p = .3055).Conclusion: Although PD-L1 expression is associated with prolonged survival, it was not identified as an independent prognostic marker. Microsatellite status did not influence long-term survival.

Identification of colon cancer subtypes based on multi-omics data-construction of methylation markers for immunotherapy.

Background: Being the most widely used biomarker for immunotherapy, the microsatellite status has limitations in identifying all patients who benefit in clinical practice. It is essential to identify additional biomarkers to guide immunotherapy. Aberrant DNA methylation is consistently associated with changes in the anti-tumor immune response, which can promote tumor progression. This study aims to explore immunotherapy biomarkers for colon cancers from the perspective of DNA methylation. Methods: The related data (RNA sequencing data and DNA methylation data) were obtained from The Cancer Genome Atlas (TCGA) and UCSC XENA database. Methylation-driven genes (MDGs) were identified through the Pearson correlation analysis. Unsupervised consensus clustering was conducted using these MDGs to identify distinct clusters of colon cancers. Subsequently, we evaluated the immune status and predicted the efficacy of immunotherapy by tumor immune dysfunction and exclusion (Tide) score. Finally, The Quantitative Differentially Methylated Regions (QDMR) software was used to identify the specific DNA methylation markers within particular clusters. Results: A total of 282 MDGs were identified by integrating the DNA methylation and RNA-seq data. Consensus clustering using the K-means algorithm revealed that the optimal number of clusters was 4. It was revealed that the composition of the tumor immune microenvironment (TIME) in Cluster 1 was significantly different from others, and it exhibited a higher level of tumor mutation burdens (TMB) and stronger anti-tumor immune activity. Furthermore, we identified three specific hypermethylation genes that defined Cluster 1 (PCDH20, APCDD1, COCH). Receiver operating characteristic (ROC) curves demonstrated that these specific markers could effectively distinguish Cluster 1 from other clusters, with an AUC of 0.947 (95% CI 0.903-0.990). Finally, we selected clinical samples for immunohistochemical validation. Conclusion: In conclusion, through the analysis of DNA methylation, consensus clustering of colon cancer could effectively identify the cluster that benefit from immunotherapy along with specific methylation biomarkers.

Evaluation of the efficacy and safety of first- and second-line immunotherapy in patients with metastatic colorectal cancer: a systematic review and network meta-analysis based on randomized controlled trials.

Background: A multitude of randomized controlled trials (RCTs) conducted in both the initial and subsequent treatment settings for patients diagnosed with metastatic colorectal cancer (mCRC) have provided clinical evidence supporting the efficacy of immunotherapy with the use of immune checkpoint inhibitors (ICIs). In light of these findings, the U.S. Food and Drug Administration (FDA) has authorized the use of several ICIs in specific subpopulations of mCRC patients. Nevertheless, there remains a dearth of direct comparative RCTs evaluating various treatment options. Consequently, the most effective ICI therapeutic strategy for microsatellite-stable (MSS) subgroup and microsatellite instability (MSI) subgroup in the first- and second-line therapies remains undefined. To address this gap, the present study employs a Bayesian network meta-analysis to ascertain the most effective first- and second-line ICI therapeutic strategies. Methods: A comprehensive literature search was conducted across multiple databases, including PubMed, EMBASE, Cochrane Library, and Web of Science, with the retrieval date ranging from the databases' inception to August 20, 2024. A total of 875 studies were identified, and seven were ultimately included in the analysis after a screening process. A systematic review and network meta-analysis were conducted on the basis of the search results. Results: This comprehensive analysis, comprising seven RCTs, evaluated first-line and second-line immunotherapy regimens in 1,358 patients diagnosed with mCRC. The treatments under investigation consisted of five initial treatments, including three focusing on MSS patients and two on MSI patients, as well as two secondary immunotherapy regimens, both focusing on MSS patients. A total of 1051 individuals underwent first-line treatment, while 307 received second-line treatment. The application of ICIs proved to offer varying degrees clinical benefits when compared to standard-of-care therapy alone, both in two subgroups of the first and the second treatment phases. Of particular note is the performance of Nivolumab combination with ipilimumab, which demonstrated superior efficacy in improving progression-free survival (PFS) (HR=0.21; 95% CI, 0.13-0.34),. Moreover, the treatment demonstrated an optimal safety profile, with a relatively low risk of adverse events (OR = 0.33; 95% CI, 0.19-0.56), compared to other first-line treatment modalities for MSI subgroup. Regarding MSS subgroup, the improvement of PFS by Nivolumab plus standard-of-care (SOC) was relatively significant (HR = 0.74; 95% CI, 0.53-1.02). In the realm of second-line therapies for MSS subgroup, the administration of Atezolizumab plus SOC has proven to be an effective approach for prolonging PFS, exhibiting an HR of 0.66 (95% CI, 0.44-0.99). These findings underscore the clinical benefits and safety profiles of ICIs in the treatment of mCRC across various treatment lines. Conclusions: The clinical application of ICIs in both first- and second-line treatment strategies for patients with mCRC yields substantial therapeutic benefits. A detailed assessment in this study indicates that first-line treatment with Nivolumab combination with ipilimumab may represent an efficacious and well-tolerated therapeutic approach for MSI subgroup. In terms of MSS subgroup in first-line therapy, Nivolumab plus SOC may be a relative superior choice. In the context of second-line therapy for MSS subgroup, it is evident that a combination of Atezolizumab and SOC represents a preferable option for enhancing PFS. Furthermore, it is noteworthy that other ICIs treatment regimens also exhibit great value in various aspects, with the potential to inform the development of future clinical treatment guidelines and provide a stronger rationale for the selection of ICIs in both first- and second-line therapeutic strategies for mCRC. Systematic review registration: https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42024543400.

Development and validation of a clinical prognostic model for BRAF V600E-mutated colorectal cancer patients based on pathological stage, microsatellite status, and primary tumor site.

Objective: To develop and validate a prognostic model for patients with BRAF V600E-mutated colorectal cancer. Methods: The clinical and pathological information of 206 patients with BRAF V600E-mutated colorectal cancer diagnosed in Cancer Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College from 2014 to 2021 was retrospectively collected. Least absolute shrinkage and selection operator (LASSO) regression, Cox regression, and nomograms were used to develop clinical prognostic models. The differentiation was measured using C-statistic, and the predicted variability was evaluated using the calibration curve. The prognostic model was externally validated using validation set data from 164 patients pooled from five studies. Results: Our clinical prognostic model included three variables: pathological stage, microsatellite status, and primary tumor site. In internal validation, the model had a concordant index of 0.785 (95% CI [0.732-0.839]) and a concordant index of 0.754 (95% CI [0.698-0.810]) using pathological staging. External validation confirmed the robustness of the model with a consistency index of 0.670 (95% CI [0.617-0.724]) and a consistency index of 0.584 (95% CI [0.546-0.622]) using pathological staging. Likelihood ratio test results show that our model is better (internal validation, p = 5.141e-03; external validation, p = 2.728e-05). The calibration graph drawn based on the prediction and the actual situation is close to the 45° diagonal. Conclusion: By adding microsatellite status and primary tumor site on the basis of pathological stage, we improved the discriminability and prediction accuracy of the model and successfully established a prognosis model for patients with BRAF V600E mutation of colorectal cancer.

Prognostic Value of Tumor Size in Colon Cancer-Smaller is Better?

BACKGROUND: The prognostic value of tumor size in colon cancer remains controversial. This study aimed to reveal the correlation between tumor size and prognosis of colon cancer. METHODS: A total of 491 patients with colon cancer were included in this study. The correlation of tumor size with prognosis, mismatch repair status, and other clinicopathological characteristics as well as tumor microenvironment was analyzed. RESULTS: For stage IIA microsatellite stable (MSS) colon cancer, tumors sized <3.5 cm and ≥5 cm were associated with a poorer disease free survival (DFS) compared with tumors sized between 3.5 and 5 cm (P = .002). Small tumor size (HR = 5.098, P = .001) and large tumor size (HR = 2.749, P = .029) were found to be independent prognostic factors for stage IIA MSS colon cancer. Moreover, high expression of transgelin (TAGLN), a marker of cancer-associated fibroblasts (CAFs), was found to be an independent prognostic factor for poorer DFS (HR = 9.651, P = .009), which was also associated with smaller tumor size (P = .027). CONCLUSION: Small (<3.5 cm) and large (≥5 cm) tumor sizes are associated with decreased DFS in stage IIA MSS colon cancer. Enrichment of TAGLN+ CAFs is associated with decreased DFS and small tumor size.

NAT10 mediated mRNA acetylation modification patterns associated with colon cancer progression and microsatellite status.

N4-acetylcytidine (ac4C) is one type of RNA modification found in eukaryotes. RNA acetylation modifications are gradually expanding in oncology. However, the role of RNA acetylation modifications in colorectal cancer and its association with colorectal cancer microsatellite status remain unclear. Using public databases and in vitro experiments, we verified the expression and biological function of NAT10, as the key RNA acetylation modification enzyme, in colorectal cancer. The results showed that NAT10 was highly expressed in colorectal cancer, and significantly promoted colorectal cancer cell proliferation. NAT10 was also involved in several aspects of cell homoeostasis such as ion transport, calcium-dependent phospholipid binding, and RNA stability. NAT10 expression positively correlated with immune infiltration in colorectal cancer. We further constructed a risk regression model for mRNA acetylation in colorectal cancer using acetylation-related differential genes. We found that tumour immune infiltration, microsatellite instability (MSI) proportion, tumour immune mutation burden, and patient response to immunotherapy were positively correlated with risk scores. For the first time, our study showed that the level of mRNA acetylation modification level is elevated in colorectal cancer and positively correlates with immune infiltration and microsatellite status of patients. Based on our findings, NAT10 may be a new target for colorectal cancer treatment.

Synchronous Colorectal Cancer: Improving Accuracy of Detection and Analyzing Molecular Heterogeneity-The Main Keys for Optimal Approach.

BACKGROUND: In patients with synchronous colorectal cancer (SCRC), understanding the underlying molecular behavior of such cases is mandatory for designing individualized therapy. The aim of this paper is to highlight the importance of transdisciplinary evaluation of the pre- and post-operative assessment of patients with SCRCs, from imaging to molecular investigations. METHODS: Six patients with SCRCs presented with two carcinomas each. In addition to the microsatellite status (MSS), the epithelial mesenchymal transition was checked in each tumor using the biomarkers ß-catenin and E-cadherin, same as KRAS and BRAF mutations. RESULTS: In two of the patients, the second tumor was missed at endoscopy, but diagnosed by a subsequent computed-tomography-scan (CT-scan). From the six patients, a total of 11 adenocarcinomas (ADKs) and one squamous cell carcinoma (SCC) were analyzed. All the examined carcinomas were BRAF-wildtype microsatellite stable tumors with an epithelial histological subtype. In two of the six cases, KRAS gene status showed discordance between the two synchronous tumors, with mutations in the index tumors and wildtype status in the companion ones. CONCLUSIONS: Preoperative CT-scans can be useful for detection of synchronous tumors which may be missed by colonoscopy. Where synchronous tumors are identified, therapy should be based on the molecular profile of the indexed tumors.

Quantitative Prediction of Microsatellite Instability in Colorectal Cancer With Preoperative PET/CT-Based Radiomics.

OBJECTIVES: Microsatellite instability (MSI) status is an important hallmark for prognosis prediction and treatment recommendation of colorectal cancer (CRC). To address issues due to the invasiveness of clinical preoperative evaluation of microsatellite status, we investigated the value of preoperative 18F-FDG PET/CT radiomics with machine learning for predicting the microsatellite status of colorectal cancer patients. METHODS: A total of 173 patients that underwent 18F-FDG PET/CT scans before operations were retrospectively analyzed in this study. The microsatellite status for each patient was identified as microsatellite instability-high (MSI-H) or microsatellite stable (MSS), according to the test for mismatch repair gene proteins with immunohistochemical staining methods. There were 2,492 radiomic features in total extracted from 18F-FDG PET/CT imaging. Then, radiomic features were selected through multivariate random forest selection and univariate relevancy tests after handling the imbalanced dataset through the random under-sampling method. Based on the selected features, we constructed a BalancedBagging model based on Adaboost classifiers to identify the MSI status in patients with CRC. The model performance was evaluated by the area under the curve (AUC), sensitivity, specificity, and accuracy on the validation dataset. RESULTS: The ensemble model was constructed based on two radiomic features and achieved an 82.8% AUC for predicting the MSI status of colorectal cancer patients. The sensitivity, specificity, and accuracy were 83.3, 76.3, and 76.8%, respectively. The significant correlation of the selected two radiomic features with multiple effective clinical features was identified (p < 0.05). CONCLUSION: 18F-FDG PET/CT radiomics analysis with the machine learning model provided a quantitative, efficient, and non-invasive mechanism for identifying the microsatellite status of colorectal cancer patients, which optimized the treatment decision support.

Identification of a 3-gene signature for predicting the prognosis of stage II colon cancer based on microsatellite status.

BACKGROUND: Though colon cancer (CC) is one of the most malignant tumors across the world, CC patients with microsatellite instability-high (MSI-H) in stage II seem to have a better prognosis. However, the molecular mechanisms underlying the phenomena haven't been elucidated yet. METHODS: This study enrolled 322 CCs with known microsatellite status from GSE143985, GSE39582 and GSE92921 in the Gene Expression Omnibus (GEO) database. Robust rank aggregation (RRA) analysis, univariate Cox regression analysis and multivariate Cox stepwise regression analysis were performed to identify genes and construct risk score signature. Kaplan-Meier and receiver operating characteristic (ROC) curves analyses were used to evaluate the prognostic value of the signature. The potential mechanisms underlying this signature were assessed in the Metascape database, gene set enrichment analysis (GSEA) and immune infiltration analysis. RESULTS: RRA analysis identified 40 differently expressed genes (DEGs). A 3-gene risk score signature (MKQ signature) associated with disease-free survival (DFS) was generated. DFS was significantly longer in CC patients with lower than higher scores (P=0.0046). The areas under curves (AUCs) of the time-dependent ROC curves of MKQ signature at 1-, 3- and 5-year DFS were 1, 0.963 and 0.961 respectively. Recurrence-free survival (RFS) was significantly longer in patients in GSE39582 with lower than higher risk scores (P=0.032). The AUCs for 1-, 3- and 5-year RFS in GSE39582 were 0.63, 0.618 and 0.583, respectively, validating the value of the MKQ signature. Functional annotation and GSEA revealed that the MKQ signature was associated with multiple immune-related pathways. Immune cell infiltration was found to differ in patients differing in the MKQ signature. CONCLUSIONS: Gene expression and microsatellite status identified a 3-gene signature (MKQ signature) that could facilitate risk-stratified management in patients with stage II CC. Dysregulation of MSMB, KRT23, and QPRT can serve as prognostic markers in stage II CC.

RNF43 frameshift mutations contribute to tumourigenesis in right-sided colon cancer.

The truncating mutations of RNF43 frequently occur in CRC, we aimed to clarify the relationship between RNF43 frameshift mutations and MS status, BRAF V600E mutation, distant metastasis, TNM stage and location of CRC. RNF43 frameshift mutations R117.fs and G659.fs and BRAF V600E mutation were detected in 392 sporadic CRC samples from our tissue bank. We integrated our original study with the TCGA database and five published datasets to analyse the relationship between RNF43 frameshift mutation and tumour location, distant metastasis, TNM stage and BRAF V600E mutation in 2396 CRC samples when controlling for MS status. RNF43 frameshift mutation was correlated with MSI-H (OR = 122.27) [31.82, 469.92], BRAF V600E mutation (OR = 7.92 [3.45, 18.18]), distant metastasis (OR = 0.30 [0.17, 0.53]), advanced TNM stage (OR = 0.34)[0.23, 0.51], and right colon site (OR = 8.32 [2.98, 23.22]). After controlling for the effect of MS status, there was no correlation of RNF43 frameshift mutation with distant metastasis (OR = 1.57 [0.75, 3.28]) and advanced TNM stages (OR = 0.98 [0.58, 1.67]), but RNF43 frameshift mutations still occur more frequently in right colon (OR = 2.58 [1.49, 4.47]) and with BRAF V600E mutation (OR = 1.94 [1.22, 3.10]). RNF43 frameshift mutations were related to distant metastasis and TNM-stage in an MS status-dependent manner, but they contributed to tumourigenesis in right-sided colon cancer independent of MS status.

Impact of microsatellite status on chemotherapy for colorectal cancer patients with KRAS or BRAF mutation.

KRAS and BRAF mutations are frequently detected in cases of colorectal cancer (CRC). The microsatellite status of patients with CRC and mutated KRAS/BRAF is important when determining cancer therapy. In the present study, the microsatellite status and genetic polymorphisms of KRAS (codons 12 and 13) and BRAF (V600E) were characterized in CRC tissue. The mismatch repair activity and oncogenic potential of KRAS were assessed by immunoblots from two KRAS-mutated CRC cell lines, SW480 and HCT116, with different microsatellite statuses, following treatment with 5-fluorouracil (5-FU) and oxaliplatin. Of all the 205 patients with CRC enrolled in the present study, 31.2% (64 of 205) had a KRAS or BRAF mutation, and 79.7% (51 of 64) of these patients with a KRAS/BRAF mutation exhibited microsatellite stability (MSS), indicating that microsatellite status is correlated with KRAS/BRAF mutation (P=0.027). A higher proportion (39.0%, 41 of 105) of elderly patients (≥62.6 years) had mutated KRAS or BRAF than younger patients (<62.6 years; 23.0%, 23 of 100; P=0.013). In the subgroup of 154 patients with MSS, patients without the KRAS or BRAF mutation (n=110) had longer disease-specific survival rates (58.8±9.4%) than patients with KRAS or BRAF mutations (n=44; 50.6±11.0%; P=0.043). Cytoplasmic KRAS levels decreased whereas nuclear MutS protein homolog 2 (MSH2) levels increased slightly in CRC HCT116 cells that were microsatellite instable, following treatment with 76.9 µM 5-FU for 2 days. In microsatellite stable SW480 cells, MSH2 levels markedly increased in the nucleus following 150 µM oxaliplatin treatment for 3 days. However, no significant change was observed regarding KRAS distribution in these cells. The results of the present study suggest that it is important to identify patients with CRC who may benefit from adjuvant chemotherapy with 5-FU or oxaliplatin, particularly CRC patients with MSS and mutated KRAS or BRAF, who have poorer overall survival rates than patients with microsatellite instability. Knowledge of the microsatellite status of patients and whether they harbor KRAS or BRAF mutations may enable more effective therapeutic strategies to be developed. Further prospective studies are required to validate the findings of the current study.

Gastric cancer in young vs old Romanian patients: immunoprofile with emphasis on maspin and mena protein reactivity.

Increasing number of early-onset gastric carcinomas (GCs) and controversial results regarding the differences among young and older patients with this type of cancer are the reasons why correlation of clinicopathological factors with molecular markers is necessary. The aim of our study was to compare the demographic, clinical and immunohistochemical (IHC) aspects in Romanian patients with GC diagnosed below and above 45 years old. In 191 samples provided from patients with GC, the clinicopathological parameters were correlated with a panel of 15 antibodies: E-cadherin, HER-2, VEGF, CD31, CD105, COX-2, maspin, bax, bcl-2, p53, Ki67, MLH-1, MSH-2, mena protein and vimentin. Compared to the conventional cases, GCs diagnosed below 45 years old were more frequently located at the gastroesophageal junction and presented a higher percentage of lymph node metastases. The diffuse type E-cadherin/mena/p53/Ki67/bax-negative cases that displayed nuclear maspin positivity were also more frequently in younger patients. The intestinal type early-onset GCs were the most angiogenic ones, the apoptotic rate being lower than in the intestinal type GCs of the aged. Compared to the conventional cases, in the early-onset GCs the nuclear maspin-mediated antiproliferative activity is more intense in diffuse type while the mena-dependent tumor cell proliferation is more characteristic for intestinal type GCs.