Early-stage Colorectal Cancer Patients Research Articles

Abstract 737: Arrays of 3D ECM-embedded fibroblast clusters for characterization of ECM remodeling by primary cancer associated fibroblasts and for evaluation of drugs attenuating fibrotic ECM remodeling

Abstract Chronic fibrosis can lead to organ failure and is also associated with cancer, where the tumor is interpreted as a chronic wound, and the fibrotic tumor environment drives disease progression. Fibrosis occurs in an inflammatory environment where macrophages are activated, and fibroblasts transdifferentiate into myofibroblasts. Activated macrophages stimulate the myofibroblasts to produce excessive amounts of collagen-rich ECM. Changes in proteolytic activity and high contractile forces that myofibroblasts apply onto their tissue environment, further lead to extensive remodeling of the healthy tissue matrix into a scar matrix. Similar activity is displayed by cancer-associated fibroblasts (CAFs) in tumors. Intervening with the excessive ECM remodeling by activated fibroblasts represents a candidate therapeutic strategy to normalize the architecture of fibrotic and malignant tissues. We developed a screening platform using an assay based on automated image guided injection of clusters of fibroblasts in wells of multi-well plates preloaded with a collagen-rich ECM network. The identical x-y-z position, spacing, and size of the ECM-embedded fibroblast clusters in each well facilitates automated real time confocal microscopy and quantitative image analysis algorithms. We use this setup for automated quantitative analysis of ECM remodeling activity of CAFs obtained from early-stage colorectal cancer patients. We find that CAFs from these early-stage lesions display increased ECM remodeling capacity as compared to patient matched normal fibroblasts. We then use the same setup to screen a series of compounds for their ability to attenuate ECM remodeling triggered by TGFb-activated primary human fibroblasts. We detect known and novel pathways, and we identify small molecule inhibitors with a promising efficacy versus toxicity profile. Lastly, we detect a previously unknown concentration-dependent side effect of ALK5 inhibitors that leads to the identification of a novel profibrotic pathway and indicates that caution is warranted for the clinical application of ALK5 inhibitors. Citation Format: Erik H. J. Danen. Arrays of 3D ECM-embedded fibroblast clusters for characterization of ECM remodeling by primary cancer associated fibroblasts and for evaluation of drugs attenuating fibrotic ECM remodeling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 737.

Abstract 2566: Molecular characteristic profile in early colorectal cancer with V600E and non-V600E BRAF mutations

Abstract Background: The BRAF V600E mutation in colorectal cancer (CRC) is a significant indicator of poor prognosis, especially in tumors exhibiting microsatellite instability (MSI). It is more common on the right side of the colon but can occur anywhere within the colon. Although other BRAF mutations existed, current research primarily focused on BRAF V600E. Most clinical data sets were centered on advanced colorectal cancer. There was limited understanding of the molecular characteristics of early-stage colorectal cancer patients with BRAF mutations, which impacted postoperative prognosis management, including refining adjuvant therapy regimens. Therefore, we analyzed the molecular characteristics of early-stage CRC surgical patients. Methods: Tumor tissue from 767 early-stage CRC patients diagnosed between 2021 to 2022 in China were analyzed using NGS (panel on 733 gene) to validate the mutation characteristics. Tumor specimens were tested for the BRAF mutation and MSI status. Result: Among 767 early CRC cases tested, BRAF mutations accounted for 6.52% (50/767), with 62% (31/50) being BRAF V600E, followed by 14% (7/50) for BRAF D594G. Notably, there were two cases of fusion variations, TRIM24-BRAF, and one case of BRAF copy gain. Among the BRAF mutation population, 11 cases were MSI-H, with 8 of them being BRAF V600E/MSI-H. Only one MSH-H patient had a germline mutation in the MLH1 gene, with a concurrent mutation in BRAF K601T.Interestingly, when comparing the mutation profiles of the BRAF V600E population with those of the non-V600E BRAF mutation population, we found distinct co-mutated genes despite both being BRAF mutations. In the BRAF V600E group, the top three frequently mutated genes were TP53 (52%), RNF43 (32%), and SMAD4 (32%). Additionally, the BRAF V600E/MSI-H subgroup presented a distinct mutation profile, with minimal occurrences of TP53 and SMAD4 mutations. In the non-V600E BRAF mutation group, the top three frequently mutated genes were TP53 (84%), APC (63%), and KRAS (32%). Conclusions: In examining the mutation profile characteristics of early colorectal cancer with BRAF mutations, the proportion of BRAF V600E/MSI-H appeared to have been lower than that reported in advanced cases. Furthermore, in terms of the frequency of co-mutated genes, it seemed that BRAF V600E had exhibited a higher malignant driving mutation effect as a single gene, while non-V600E mutations had required more cooperative tumor suppressor genes or oncogenes. Analyzing the molecular characteristics of early colorectal cancer patients with V600E and non-V600E BRAF mutations could help improve postoperative management and further our understanding of tumor progression. Citation Format: Zhang Quan An. Molecular characteristic profile in early colorectal cancer with V600E and non-V600E BRAF mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2566.

MRD assay to evaluate recurrence and response via a tumor informed assessment: MARIA-Colorectal Cancer Observational trial.

TPS242 Background: The detection of ctDNA in patients with colorectal cancer (CRC) is emerging as a potential biomarker to identify patients at high risk of relapse, assess treatment response and monitor for recurrence. Solid tumors are currently monitored by imaging studies, tumor markers and clinical symptoms and recent studies suggest tumor-informed molecular residual disease (MRD) testing may outperform these current methods and may serve as a prognostic biomarker to aid in the identification of patients at high risk of relapse (Reinert et al, 2019; Christensen et al, 2019; Coombes et al, 2019). Recent studies have demonstrated that tumor-informed MRD testing can detect relapse prior to detection with imaging in CRC and while interventional trials are needed, this may provide an opportunity for therapeutic intervention (Reinert et al, 2019; Kotani et al, 2023). This study utilizes the Invitae Personalized MonitoringTM (PCM) test, a highly sensitive tumor-informed MRD test (Zhao et al, 2023), to monitor early stage CRC patients. Methods: MARIA is a multi-site, prospective, observational trial in the United States of 200 newly diagnosed patients with early stage (high risk stage II, stage III and stage IV oligometastases) CRC undergoing curative intent treatment. Formalin fixed paraffin embedded (FFPE) tissue from the biopsy or surgical specimen is utilized to create the PCM test. Tumor tissue and a matched normal blood sample will undergo whole exome sequencing to identify 18-50 unique tumor variants to create a patient specific panel (PSP) for ctDNA analysis. Participants are asked to provide serial plasma specimens for ctDNA analysis at baseline, post surgical landmark and surveillance time points. A clinical report will be provided to the ordering physician. Physicians will be asked to complete a case report form for each participant when the first result is reported and every 6 months. The primary endpoint is to evaluate the correlation between the PCM test result at the landmark timepoint and the patient’s 24 month recurrence risk. Secondary endpoints include evaluating the impact on patient outcomes attributable to MRD result-based changes to treatment or clinical management, correlating between the PCM result at the baseline time point and patient recurrence risk and outcomes and investigating the lead time of PCM positivity over clinical/imaging based evidence of recurrence. Active enrollment started in March, 2022. Clinical trial information: NCT05219734 .

Clinical impact of heterogeneously distributed tumor-infiltrating lymphocytes on the prognosis of colorectal cancer.

Tumor-infiltrating lymphocytes (TILs) exist in various malignancies, and have been viewed as a promising biomarker to predict the efficacy and outcome of treatment. However, the marked inter- and intra-tumor heterogeneity of TILs has resulted in some confusion regarding their impact on the prognosis of colorectal cancer (CRC). In this study, 78 CRC patients were enrolled and the CD3+ and CD8+ TILs densities at the tumor center (TC), the invasive margin (IM) and the tumor stroma (TS) were assessed by immunohistochemical staining. Their associations with clinicopathological features and progression free survival (PFS) were analyzed to evaluate the predictive and prognostic values of TILs. TILs were mainly distributed along the invasive margin. High density of TILs in tumor center and invasive margin was associated with smaller tumor size (CD3+TILsIM), reduced tumor invasion (CD3+TILsIM), absence of lymph node metastasis (CD3+TILsIM and CD8+TILsTC), earlier stage (CD3+TILsIM and CD8+TILsIM), and lower tumor grade (CD3+TILsIM and CD8+TILsTC). However, stromal TILs were not associated with any clinicopathological features. Kaplan-Meier survival analysis revealed that high densities of TILs always correlated with prolonged patient survival. The pathological N stage, CD3+ TILsIM and CD8+ TILsTC were found to be independent prognostic indicators. Additionally, early-stage CRC patients who developed recurrence after surgery, showed a higher CD3+/CD8+ TILs ratio in invasive margin. In the present study, it was clarified that CD3+ and CD8+ TILs were heterogeneously distributed in tumor tissues of CRC. The increase in intratumoral and peritumoral TILs had been shown to be strongly predictive of improved clinical outcome. More importantly, the immune signatures enabled to stratify early-stage CRC patients with high risk of recurrence, highlighting the prognostic power of TILs.

417P Early experience in using plasma-only multi-omic minimal residual disease testing in early-stage colorectal cancer patients from Asia and the Middle East

417P Early experience in using plasma-only multi-omic minimal residual disease testing in early-stage colorectal cancer patients from Asia and the Middle East

PD-L1 and BRAFV600E Expression on CTCs from Early-stage Colorectal Cancer Patients

PD-L1 and BRAFV600E Expression on CTCs from Early-stage Colorectal Cancer Patients

Association between metabolic syndrome and early-stage colorectal cancer

BackgroundAccumulating studies have suggested metabolic syndrome (MetS) contributed to colorectal cancer (CRC) development. However, advanced CRC might decrease the detection proportion of MetS due to chronic malnutrition, we included patients with early-stage CRC to examine the associations among MetS, onset age, and different tumorigenesis pathways of CRC.MethodsWe conducted a retrospective study that included 638 patients with early-stage CRC from January 2014 to December 2018. Patient information was collected from the medical record system and further refined during the follow-up. Stratified analyses of the associations between MetS and different stratification factors were determined by the Cochran‒Mantel‒Haenszel test.ResultsThere were 16 (13.3%) and 111 (21.4%) cases suffering from MetS in the early-onset and late-onset CRC groups, respectively. MetS coexisted in early-stage CRC patients ≥ 50 years of age more frequently than patients < 50 years of age (OR 1.77; 95% CI 1.01 to 3.12), but not for women patients (OR 0.84; 95% CI 0.79 to 0.90). MetS patients were associated with a higher risk of advanced serrated lesions than that of conventional adenomas (OR 1.585; 95% CI 1.02 to 2.45), especially in patients ≥ 50 years (OR 1.78; 95% CI 1.11 to 2.85).ConclusionsMetabolic dysregulation might partly contribute to the incidence of colorectal serrated lesions. Prevention of MetS should be highly appreciated in the early diagnosis and early treatment of the colorectal cancer system, especially in patients ≥ 50 years.

Outcome of Completion Surgery after Endoscopic Submucosal Dissection in Early-Stage Colorectal Cancer Patients.

T1 colorectal cancers (T1CRC) are increasingly being treated by endoscopic submucosal dissection (ESD). After ESD of a T1CRC, completion surgery is indicated in a subgroup of patients. Currently, the influence of ESD on surgical morbidity and mortality is unknown. The aim of this study was to compare 90-day morbidity and mortality of completion surgery after ESD to primary surgery. The completion surgery group consisted of suspected T1CRC patients from a multicenter prospective ESD database (2014-2020). The primary surgery group consisted of pT1CRC patients from a nationwide surgical registry (2017-2019). Patients with rectal or sigmoidal cancers were selected. Patients receiving neoadjuvant therapy were excluded. Propensity score adjustment was used to correct for confounders. In total, 411 patients were included: 54 in the completion surgery group (39 pT1, 15 pT2) and 357 in the primary surgery group with pT1CRC. Adverse event rate was 24.1% after completion surgery and 21.3% after primary surgery. After completion surgery 90-day mortality did not occur, though one patient died in the primary surgery group. After propensity score adjustment, lymph node yield did not differ significantly between the groups. Among other morbidity-related outcomes, stoma rate (OR 1.298 95%-CI 0.587-2.872, p = 0.519) and adverse event rate (OR 1.162; 95%-CI 0.570-2.370, p = 0.679) also did not differ significantly. A subgroup analysis was performed in patients undergoing rectal surgery. In this subgroup (37 completion and 136 primary surgery), these morbidity outcomes also did not differ significantly. In conclusion, this study suggests that ESD does not compromise morbidity or 90-day mortality of completion surgery.

The risk of second primary malignancies in colorectal cancer patients using calcium channel blockers

Calcium channel blockers are among the most commonly used agents in the treatment of cardiovascular diseases. There are several known side-effects associated with their long-term use, whereas other potential adverse effects are yet to be proven. This study aims to evaluate the association between calcium channel blockers exposure and the incidence of second primary malignancy. We established a cohort of 1401 patients with colorectal cancer diagnosed in our institution between January 2003 and December 2016. Patients were followed-up until December 2020. The tumor characteristics and basic clinical data including medication information were obtained from the hospital information system database. Second malignancy was detected in 301 patients (21.5%), and occurred in 27.8% of patients who used calcium channel blockers compared to only 19.9% among non-users. Their use was associated with an increased incidence of bladder cancer in particular. Subanalysis of patients with second malignancy displayed a higher proportion of right-sided colon cancer compared to rectal carcinoma in non-users. Survival analysis revealed significantly better outcomes in early-stage colorectal cancer patients without a history of calcium channel blockers treatment or second primary malignancy.

Construction of Exosome SORL1 Detection Platform Based on 3D Porous Microfluidic Chip and its Application in Early Diagnosis of Colorectal Cancer.

Exosomes are promising new biomarkers for colorectal cancer (CRC) diagnosis, due to their rich biological fingerprints and high level of stability. However, the accurate detection of exosomes with specific surface receptors is limited to clinical application. Herein, an exosome enrichment platform on a 3D porous sponge microfluidic chip is constructed and the exosome capture efficiency of this chip is ≈90%. Also, deep mass spectrometry analysis followed by multi-level expression screenings revealed a CRC-specific exosome membrane protein (SORL1). A method of SORL1 detection by specific quantum dot labeling is further designed and the ensemble classification system is established by extracting features from 64-patched fluorescence images. Importantly, the area under the curve (AUC) using this system is 0.99, which is significantly higher (p< 0.001) than that using a conventional biomarker (carcinoembryonicantigen(CEA), AUC of 0.71). The above system showed similar diagnostic performance, dealing with early-stage CRC, young CRC, and CEA-negative CRC patients.

Development and validation of postoperative circulating tumor DNA combined with clinicopathological risk factors for recurrence prediction in patients with stage I-III colorectal cancer

BackgroundCirculating tumor DNA (ctDNA) detection following curative-intent surgery could directly reflect the presence of minimal residual disease, the ultimate cause of clinical recurrence. However, ctDNA is not postoperatively detected in ≥ 50% of patients with stage I-III colorectal cancer (CRC) who ultimately recur. Herein we sought to improve recurrence risk prediction by combining ctDNA with clinicopathological risk factors in stage I-III CRC.MethodsTwo independent cohorts, both consisting of early-stage CRC patients who underwent curative surgery, were included: (i) the discovery cohort (N = 124) with tumor tissues and postoperative plasmas for ctDNA determination; and (ii) the external validation cohort (N = 125) with available ctDNA results. In the discovery cohort, somatic variations in tumor tissues and plasmas were determined via a 733-gene and 127-gene next-generation sequencing panel, respectively.ResultsIn the discovery cohort, 17 of 108 (15.7%) patients had detectable ctDNA. ctDNA-positive patients had a significantly high recurrence rate (76.5% vs. 16.5%, P < 0.001) and short recurrence-free survival (RFS; P < 0.001) versus ctDNA-negative patients. In addition to ctDNA status, the univariate Cox model identified pathologic stage, lymphovascular invasion, nerve invasion, and preoperative carcinoembryonic antigen level associated with RFS. We combined the ctDNA and clinicopathological risk factors (CTCP) to construct a model for recurrence prediction. A significantly higher recurrence rate (64.7% vs. 8.1%, P < 0.001) and worse RFS (P < 0.001) were seen in the high-risk patients classified by the CTCP model versus those in the low-risk patients. Receiver operating characteristic analysis demonstrated that the CTCP model outperformed ctDNA alone at recurrence prediction, which increased the sensitivity of 2 year RFS from 49.6% by ctDNA alone to 87.5%. Harrell's concordance index, calibration curve, and decision curve analysis also suggested that the CTCP model had good discrimination, consistency, and clinical utility. These results were reproduced in the validation cohort.ConclusionCombining postoperative ctDNA and clinical risk may better predict recurrence than ctDNA alone for developing a personalized postoperative management strategy for CRC.

Recurrence risk assessment for stage III colorectal cancer based on five methylation biomarkers in plasma cell-free DNA.

For stage III colorectal cancer (CRC) patients with a high risk of recurrence, intensified adjuvant chemotherapy can improve overall survival. We aimed to develop a circulating tumor DNA (ctDNA) methylation marker model for predicting the relapse risk of stage III CRC patients. Differentially methylated markers identified between 53 normal mucosa samples and 165 CRC tissue samples, as well as between plasma samples from 75 stage I/II (early-stage) CRC patients and 55 stage IV (late-stage) CRC patients, were analyzed using Student's t-tests. The overlapping methylation markers shared by plasma and tissue samples were used to establish a methylation marker model to evaluate the tumor burden in the peripheral blood of CRC patients using the random forest method. This model was verified in the validation cohort (n = 44) and then applied to predict recurrence risk in 50 stage III CRC patients and monitor the clinical disease course in serial samples from four CRC patients. We built a five-marker-based ctDNA methylation model that had high sensitivity (84.21%) and specificity (84%) in identifying late-stage CRC in a validation cohort containing 24 stage I/II CRC patients and 20 stage IV CRC patients. The model achieved high sensitivity (87.5%) and specificity (94.12%) in predicting tumor relapse in an independent cohort of 50 stage III CRC patients and could be an independent recurrence risk factor for stage III patients [Hazard ratio (HR), 60.4; 95% confidence interval (CI): 7.68-397; p = 9.73e-5]. Analysis of serial blood samples of CRC showed that the model could monitor disease relapse earlier than imaging examination and serum carcinoembryonic antigen (CEA) and so may provide an opportunity for the early adjustment of therapeutic strategies. Moreover, the model could potentially monitor the clinical course and treatment response dynamically. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Identification of biomarkers predictive of metastasis development in early-stage colorectal cancer using network-based regularization

Colorectal cancer (CRC) is the third most common cancer and the second most deathly worldwide. It is a very heterogeneous disease that can develop via distinct pathways where metastasis is the primary cause of death. Therefore, it is crucial to understand the molecular mechanisms underlying metastasis. RNA-sequencing is an essential tool used for studying the transcriptional landscape. However, the high-dimensionality of gene expression data makes selecting novel metastatic biomarkers problematic. To distinguish early-stage CRC patients at risk of developing metastasis from those that are not, three types of binary classification approaches were used: (1) classification methods (decision trees, linear and radial kernel support vector machines, logistic regression, and random forest) using differentially expressed genes (DEGs) as input features; (2) regularized logistic regression based on the Elastic Net penalty and the proposed iTwiner—a network-based regularizer accounting for gene correlation information; and (3) classification methods based on the genes pre-selected using regularized logistic regression. Classifiers using the DEGs as features showed similar results, with random forest showing the highest accuracy. Using regularized logistic regression on the full dataset yielded no improvement in the methods’ accuracy. Further classification using the pre-selected genes found by different penalty factors, instead of the DEGs, significantly improved the accuracy of the binary classifiers. Moreover, the use of network-based correlation information (iTwiner) for gene selection produced the best classification results and the identification of more stable and robust gene sets. Some are known to be tumor suppressor genes (OPCML-IT2), to be related to resistance to cancer therapies (RAC1P3), or to be involved in several cancer processes such as genome stability (XRCC6P2), tumor growth and metastasis (MIR602) and regulation of gene transcription (NME2P2). We show that the classification of CRC patients based on pre-selected features by regularized logistic regression is a valuable alternative to using DEGs, significantly increasing the models’ predictive performance. Moreover, the use of correlation-based penalization for biomarker selection stands as a promising strategy for predicting patients’ groups based on RNA-seq data.

Correlation between Stool DNA-based SDC2 Methylation Tests Combined with Tumor Markers with Pathological Features in Colorectal Cancer.

Colorectal cancer (CRC) screening is the most efficient strategy to reduce disease-related mortality. In this study, we aimed to investigate the association of a methylation-based stool DNA test with serum protein biomarker panel (CEA, CA125, CA199, and AFP) in CSC patients and their relationship with pathological features to improve the diagnostic efficacy and applicability in CSC in the Chinese population. In this double-blinded case-control study, we enrolled 150 participants from our hospital, including 50 CRC patients, 50 adenomas, and 50 healthy controls. We compared the cycling threshold (Ct) values of stool DNA-based SDC2 measured by quantitative methylation-specific PCR (MSP) in the three groups. We also evaluated the differences and correlation between serum concentrations of tumor biomarker and pathological features in patients with CSC, including TNM stage (I, II, III), tumor size, and lymph node metastasis. The discrimination performance of indexes was assessed using sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). CSC was more common in middle-aged people and men. The methylation-based stool DNA test was not significantly correlated with other tumor indicators except CEA, and the difference was statistically significant. Compared with the normal control group, the combined diagnostic value of the methylation-based stool DNA test and tumor indicators was significantly higher than individual biomarkers alone, especially the methylation-based stool DNA test combined with CEA and AFP, which improved the AUC to 0.96. This combination can increase the positive rate of pathological stage diagnosis. Combining a methylation-based stool DNA test with CEA and AFP can significantly improve the diagnostic value of CRC and can be used to confirm the diagnosis of colorectal cancer. This combination can also be used as a reliable indicator identifying early-stage CRC patients and pathology. A large-scale study is underway to further define the clinical application of this method for the diagnosis of CRC among Chinese populations.

Cytology Smears: An Enhanced Alternative Method for Colorectal Cancer pN Stage-A Multicentre Study.

Stage II colorectal cancer (CRC) recurrence remains a clinical problem. Some of these patients are true stage III CRC with a pN0 pathology stage. This large prospective multicentre cohort study aimed at evaluating the diagnostic ability of lymph node (LN) cytology smears to perform the pN stage and compare it with the conventional haematoxylin and eosin (H&E) pathology pN stage. Additionally, we used the One-Step Nucleic Acid Amplification (OSNA), a high-sensitive molecular method of LN staging. A total of 3936 fresh LNs from 217 CRC surgical specimens were examined by three methods, H&E, LN cytology smears, and OSNA. H&E detected 29% of patients with positive LNs, cytology smears 35%, and OSNA 33.2% (p &lt; 0.0001). H&E and cytology concordantly classified 92.2% of tumours, and 88.5% between OSNA and H&E. Cytology had 96.8% sensitivity and 90.3% specificity to discriminate positive/negative patients compared to H&E (p = 0.004), and 87.3% sensitivity and 89% specificity when compared to OSNA (p = 0.56). Patients with positive LNs detected by any of the three methods had significantly worse disease-free and overall survival. We conclude that pN stage accuracy for detecting positive LNs is superior with LN cytological smears than with conventional H&E, which would enable a better pN stage and management of early-stage CRC patients.

65P Comparison of survival and recurrence pattern in Thai early stage colorectal cancer patients by tumor sidedness

Sidedness of colorectal cancer (CRC) can exhibit different molecular alteration, presentation, histology, and prognosis. Left-sided CRC has a better prognosis in term of progression and recurrent disease. We aimed to compare sidedness of CRC in terms of survival and recurrence in early stage of Thai CRC patients.

Characteristics of circulating adaptive immune cells in patients with colorectal cancer

Adaptive immune cells prevent solid tumor progression by targeting and killing tumor cells. However, there are no comprehensive studies on peripheral circulating adaptive immune cell characterization in colorectal cancer (CRC) patients or the effect of tumor-node-metastasis (TNM) stages on these cells. In this study, the number, phenotype, and function of different subsets of circulating adaptive immune cells in peripheral blood of CRC patients were analyzed. We found remarkable differences in CRC patients compared with those in healthy controls, including reduced absolute counts of total T cells, helper T lymphocytes (Th), cytotoxic T lymphocytes (Tc), and double-negative T lymphocytes, a decreased proportion of INF-γ+ cells in total T cells and Th, and increased percentages of B cells, plasmablasts, and activated T cells. Compared with early-stage CRC patients, advanced-stage CRC patients showed more severe immunosenescence, which manifested as decreased proportions of CD8+ naive T cells with strong proliferative ability and CD8+ central memory T cells with immune surveillance function. Proportions and absolute counts of CD8+ and CD4+ terminally differentiated effector memory T cells were increased, indicating immunosenescence. The immune cell characteristics analyzed in this study serve as a starting point for further research to determine potential clinical implications.

DNA methylation profile in CpG-depleted regions uncovers a high-risk subtype of early-stage colorectal cancer.

The current risk stratification system defined by clinicopathological features does not identify the risk of recurrence in early-stage (stage I-II) colorectal cancer (CRC) with sufficient accuracy. We aimed to investigate whether DNA methylation could serve as a novel biomarker for predicting prognosis in early-stage CRC patients. We analyzed the genome-wide methylation status of CpG loci using Infinium MethylationEPIC array run on primary tumor tissues and normal mucosa of early-stage CRC patients to identify potential methylation markers for prognosis. The machine-learning approach was applied to construct a DNA methylation-based prognostic classifier for early-stage CRC (MePEC) using the 4 gene methylation markers FAT3, KAZN, TLE4, and DUSP3. The prognostic value of the classifier was evaluated in 2 independent cohorts (n = 438 and 359, respectively). The comprehensive analysis identified an epigenetic subtype with high risk of recurrence based on a group of CpG loci in the CpG-depleted region. In multivariable analysis, the MePEC classifier was independently and statistically significantly associated with time to recurrence in validation cohort 1 (hazard ratio = 2.35, 95% confidence interval = 1.47 to 3.76, P < .001) and cohort 2 (hazard ratio = 3.20, 95% confidence interval = 1.92 to 5.33, P < .001). All results were further confirmed after each cohort was stratified by clinicopathological variables and molecular subtypes. We demonstrated the prognostic statistical significance of a DNA methylation profile in the CpG-depleted region, which may serve as a valuable source for tumor biomarkers. MePEC could identify an epigenetic subtype with high risk of recurrence and improve the prognostic accuracy of current clinical variables in early-stage CRC.

1701P Consensus molecular subtypes in late-stage colorectal cancer

In 2015, the Colorectal Cancer (CRC) Subtyping Consortium published four gene expression consensus molecular subtypes (CMS) from early stage CRC patients: CMS1 (immune), CMS2 (canonical), CMS3 (metabolic), and CMS4 (mesenchymal). The distribution of CMS groups is not well described for late-stage CRC.

Early detection of colorectal cancer based on circular DNA and common clinical detection indicators.

BACKGROUNDColorectal cancer (CRC) is the third most common cancer worldwide, and it is the second leading cause of death from cancer in the world, accounting for approximately 9% of all cancer deaths. Early detection of CRC is urgently needed in clinical practice.AIMTo build a multi-parameter diagnostic model for early detection of CRC. METHODSTotal 59 colorectal polyps (CRP) groups, and 101 CRC patients (38 early-stage CRC and 63 advanced CRC) for model establishment. In addition, 30 CRP groups, and 62 CRC patients (30 early-stage CRC and 32 advanced CRC) were separately included to validate the model. 51 commonly used clinical detection indicators and the 4 extrachromosomal circular DNA markers NDUFB7, CAMK1D, PIK3CD and PSEN2 that we screened earlier. Four multi-parameter joint analysis methods: binary logistic regression analysis, discriminant analysis, classification tree and neural network to establish a multi-parameter joint diagnosis model. RESULTSNeural network included carcinoembryonic antigen (CEA), ischemia-modified albumin (IMA), sialic acid (SA), PIK3CD and lipoprotein a (LPa) was chosen as the optimal multi-parameter combined auxiliary diagnosis model to distinguish CRP and CRC group, when it differentiated 59 CRP and 101 CRC, its overall accuracy was 90.8%, its area under the curve (AUC) was 0.959 (0.934, 0.985), and the sensitivity and specificity were 91.5% and 82.2%, respectively. After validation, when distinguishing based on 30 CRP and 62 CRC patients, the AUC was 0.965 (0.930-1.000), and its sensitivity and specificity were 66.1% and 70.0%. When distinguishing based on 30 CRP and 32 early-stage CRC patients, the AUC was 0.960 (0.916-1.000), with a sensitivity and specificity of 87.5% and 90.0%, distinguishing based on 30 CRP and 30 advanced CRC patients, the AUC was 0.970 (0.936-1.000), with a sensitivity and specificity of 96.7% and 86.7%.CONCLUSIONWe built a multi-parameter neural network diagnostic model included CEA, IMA, SA, PIK3CD and LPa for early detection of CRC, compared to the conventional CEA, it showed significant improvement.