Circulating tumour cells in gastrointestinal cancers: food for thought?

CTCs and liquid biopsies in patients with colorectal cancer

Liquid biopsy, which includes both circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs) has become a valuable tool for cancer diagnosis and monitoring. It offers a less invasive approach than traditional tissue biopsy and recent technological advancements have enabled their use in comprehensive analysis of tumor molecular characteristics. By capturing the dynamic nature of tumors through repeated sampling, liquid biopsy addresses the limitations of tissue biopsy and provides insights into tumor heterogeneity over time. It is being extensively studied in patients with advanced colorectal cancer because it can aid in diagnosis, predict disease course, and guide treatment selection. Furthermore, as personalized medicine becomes more common, identifying genetic changes that cause cancer cells to become resistant to treatment is crucial. This chapter explores the emerging field of liquid biopsy, with a particular focus on the role and potential of circulating tumor cells (CTCs) in the context of colorectal cancer.

Immune biomarkers and predictive signatures in gastric cancer: Optimizing immunotherapy responses

Gastric cancer is a malignant disease with a poor prognosis and few therapeutic options once it has advanced. Immunotherapy using ICIs has emerged as a viable therapeutic method; nevertheless, reliable immunological biomarkers are required to identify who may benefit from these therapies. It focuses on key immune biomarkers and predictive signatures in gastric cancer, such as PD-L1 expression, microsatellite instability (MSI), tumor mutational burden (TMB), and Epstein-Barr virus (EBV) status, to optimize gastric cancer patients' immunotherapy responses. PD-L1 expression is a popular biomarker for ICI effectiveness. Tumors with high MSI-H and TMB are the most susceptible to ICIs because they are highly immunogenic. EBV-positive stomach tumors are highly immunogenic, and immunotherapy has a high response rate. Combining composite biomarker panels with multi-omics-based techniques improved patient selection accuracy. In recent years, machine learning models have been integrated into next-generation sequencing. Dynamic, real-time-monitorable biomarkers for real-time immune response monitoring are also being considered. Thus, enhancing biomarker-driven immunotherapy is critical for improving clinical outcomes with gastric cancer. There is still more work to be done in this field, and verifying developing biomarkers will be an important component in the future of customized cancer therapy.

Cancer-associated macrophage-like cells as a prognostic biomarker in solid tumors

Cancer-associated macrophage-like cells (CAMLs) are myeloid-lineage cells associated with cancer-derived material that are detectable in the blood. In addition to circulating tumor cells, CAMLs are a promising liquid biopsy biomarker which may assist with prognostication for patient stratification and monitoring response to chemotherapy and radiotherapy in solid tumors. CAMLs have been detected in blood samples from patients with various tumors including lung, pancreas, breast, oesophageal, and colorectal cancers, and to date have not been detected in healthy individuals. However, the optimal method of detection, their origin, function in the circulation, and ultimate utility have not been fully elucidated. This review provides an overview of CAML-related studies and explores their future potential to guide clinical decision-making.

Novel Immunological Markers of Intestinal Impairment Indicative of HIV-1 Status and/or Subclinical Atherosclerosis

Antiretroviral therapy (ART) controls HIV-1 replication in people with HIV-1 (PWH), but immunological restauration at mucosal barrier surfaces is not achieved. This fuels microbial translocation, chronic immune activation, and increased comorbidities, including cardiovascular disease (CVD). Here, we sought to identify novel markers of mucosal barrier impairment in the blood to predict the HIV and/or CVD status. Flow cytometry was used to characterize CD326/EpCAM + intestinal epithelial cells (IEC); CD4 + T-cells; CD8 + and CD4 + intraepithelial lymphocytes (IELs); and subsets of CD4 + T-cells expressing Th17 (CCR6) and gut-homing (Itgβ7) markers. To this aim, we collected peripheral blood mononuclear cells (PBMCs) from 42 ART-treated PWH (HIV + ) and 40 uninfected participants (HIV - ) from the Canadian HIV and Aging Cohort Study (CHACS). Both groups were categorized based on the presence of coronary atherosclerotic plaques measured by CT scan angiography as total plaque volume (TPV, mm 3 ). Our findings associate the HIV-1 status with increased frequencies of circulating CD326 + IEC; CD326 + CD4 + T-cells with activated (CD69 + HLA-DR + ) and gut-homing (ItgαE + CCR6 + CCR9 + ) phenotypes, CCR6 + Itgβ7 - CD4 + T-cells; and decreased frequencies of CD8 + IELs. Logistic regression analyses confirmed the predictive capacity of the above cellular markers regarding HIV status. Spearman correlation revealed a positive correlation between TPV and CCR6 + Itgβ7 - and CCR6 + Itgβ7 + CD4 + T-cell frequencies.Together, these results highlighted significant immune dysregulation and persistent mucosal barrier alterations despite effective viral suppression by ART and linked the abundance of CCR6 + Itgβ7 + and CCR6 + Itgβ7 - CD4 + T-cells to increased atherosclerotic plaque burden. Thus, strategies targeting the gut-immune axis restoration may reduce CVD onset and improve long-term health outcomes in PWH.

Clinical significance of circulating tumor cells in colorectal cancer with peritoneal metastases: a prospective cohort study using a novel method for monitoring treatment response, and assessing minimal residual disease

BACKGROUND

The treatment for patients with colorectal cancer with metastases to the peritoneum is complex and may involve both surgery and chemotherapy. Circulating tumor cells (CTCs) have been poorly investigated in peritoneal metastatic colorectal cancer. The aim of the study is to examine the role of CTCs as a biomarker for monitoring disease progression, treatment response, and residual disease using CellMate - a new promising in vitro diagnostic platform technology.

MATERIALS AND METHODS

The authors prospectively followed the clinical outcomes of 46 patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal cancer with peritoneal metastases and examined whether CTCs were present the week of surgery. The CTC measurements were made with the CellMate technology, which is a platform technology to detect CTCs based on the difference in biomechanical properties compared to blood resident cells. The study was registered online (ClinicalTrials.gov).

RESULTS

CTCs were detected in 17 (37%) patients. The presence of CTCs was associated with shorter recurrence-free survival and overall survival after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. Both recurrence-free survival (HR 4.00, 95% CI: 1.15-13.9; P =0.029) and overall survival (HR 5.91; 95% CI: 1.18-29.7; P =0.03) were significantly worse if CTCs were detected after neoadjuvant treatment. In the subgroup of patients with CTCs detected, adjuvant therapy tended to improve the prognosis while in CTC negative patients it did not.

CONCLUSIONS

Pending a prospective multicenter trial to validate these findings, CTCs may in the future be used as a dynamic personalized biomarker for prognostication, predicting response to therapy, and for monitoring disease progression in colorectal cancer with metastases to the peritoneum.

Antibody-drug conjugate adverse effects can be understood and addressed based on immune complex clearance mechanisms

ABSTRACT

Numerous antibody-drug conjugates (ADCs) are being developed for cancer immunotherapy. Although several of these agents have demonstrated considerable clinical efficacy and have won Food and Drug Administration (FDA) approval, in many instances, they have been characterized by adverse side effects (ASEs), which can be quite severe in a fraction of treated patients. The key hypothesis in this perspective is that many of the most serious ASEs associated with the use of ADCs in the treatment of cancer can be most readily explained and understood due to the inappropriate processing of these ADCs via pathways normally followed for immune complex clearance, which include phagocytosis and trogocytosis. We review the key published basic science experiments and clinical observations that support this idea. We propose that it is the interaction of the ADC with Fcγ receptors expressed on off-target cells and tissues that can most readily explain ADC-mediated pathologies, which therefore provides a rationale for the design of protocols to minimize ASEs. We describe measurements that should help identify those patients most likely to experience ASE due to ADC, and we propose readily available treatments as well as therapies under development for other indications that should substantially reduce ASE associated with ADC. Our focus will be on the following FDA-approved ADC for which there are substantial literatures: gemtuzumab ozogamicin and inotuzumab ozogamicin; and trastuzumab emtansine and trastuzumab deruxtecan.

Clinical Significance of Circulating Tumor Cells in Epithelial Appendiceal Neoplasms with Peritoneal Metastases

Appendiceal tumors are uncommon and, at times, discovered incidentally during histological examination. The histopathological classification of the disease is complex and has generated some controversy. The analysis of circulating tumor cells can be used for the early detection of metastatic potential. The aim of the present study was to examine the prognostic value of circulating tumor cells in patients with appendiceal tumors and peritoneal metastases. To our knowledge, this is the first study to examine CTCs in appendiceal tumors. We performed a prospective cohort study of consecutive patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy between 2015 and 2019 at a HIPEC referral center. In total, 31 patients were included in the analysis, and circulating tumor cells were detected in 15 patients (48%). CTC positivity was not associated with overall or recurrence-free survival, nor was it correlated with PCI score or histopathological grading. Surprisingly, however, CTCs were found in almost half the patients. The presence or quantities of these cells did not, on their own, predict systemic metastatic potential during the observed time, and they did not appear to significantly correlate with the oncological outcomes recorded.

Stereo Visual Servoing Control of a Soft Endoscope for Upper Gastrointestinal Endoscopic Submucosal Dissection

Quickly and accurately completing endoscopic submucosal dissection (ESD) operations within narrow lumens is currently challenging because of the environment's high flexibility, invisible collision, and natural tissue motion. This paper proposes a novel stereo visual servoing control for a dual-segment robotic endoscope (DSRE) for ESD surgery. Departing from conventional monocular-based methods, our DSRE leverages stereoscopic imaging to rapidly extract precise depth data, enabling quicker controller convergence and enhanced surgical accuracy. The system's dual-segment configuration enables agile maneuverability around lesions, while its compliant structure ensures adaptability within the surgical environment. The implemented stereo visual servo controller uses image features for real-time feedback and dynamically updates gain coefficients, facilitating rapid convergence to the target. In visual servoing experiments, the controller demonstrated strong performance across various tasks. Even when subjected to unknown external forces, the controller maintained robust performance in target tracking. The feasibility and effectiveness of the DSRE were further verified through ex vivo experiments. We posit that this novel system holds significant potential for clinical application in ESD surgeries.