Detection and Clinical Significance of Circulating Tumor Cells in Colorectal Cancer--20 Years of Progress

Outcomes associated with total neoadjuvant therapy with non-operative intent for rectal adenocarcinoma

Purpose/objectives

To evaluate rates of clinical complete response (cCR), surgery-free survival, permanent ostomy-free survival, and factors associated with these outcomes in patients treated with total neoadjuvant therapy (TNT) with intent for non-operative management of rectal adenocarcinoma.

Methods

A retrospective review was conducted of patients treated with TNT for stage II-IV rectal adenocarcinoma (n=45) at our institution between 2013 - 2022 with curative intent. All patients received radiation with concurrent capecitabine and additional chemotherapy, either prior to or following chemoradiation (CRT), with intent for non-operative management. Response rates were determined based on post-treatment MRI and endoscopy. Kaplan-Meier method was utilized to estimate the 1- and 2-year surgery- and permanent ostomy-free survivals. Cox regression was used to evaluate associations between surgery- and permanent ostomy-free survivals and various factors of interest, including patient and tumor characteristics and clinical response. Chi-squared analysis compared rates of cCR and surgery by sequence of TNT modality and cell count ratios.

Results

Of the 45 patients treated with TNT, most patients had low-lying rectal tumors with a median distance of 4.1 cm from the anal verge (range, 0.0 - 12.0). Overall, 64.4% (n=29) achieved cCR after TNT. 13 patients (28.9%) underwent surgical resection following TNT, 12 of whom had incomplete response and one who elected to undergo surgery after reaching cCR. At median follow up of 32.0 months (range, 7.1 - 86.1), 22.2% (n=10) of patients had a permanent colostomy, with only 2 of these completed for tumor regrowth after cCR. At one and two years, respectively, surgery-free survival was 77.3% and 66.2%, and permanent ostomy-free survival was 90.9% and 78.2%. Rates of cCR were higher in patients who received CRT first compared to those who received chemotherapy first (72.2% vs. 33.3%, p=0.029) and rates of surgery were also lower in patients who received CRT first compared to those who received chemotherapy first (19.4% vs. 66.7%, p=0.005). On Cox regression model, cCR on 6 month post-CRT endoscopy was associated with surgery-free survival (p=0.006) and permanent ostomy-free survival (p=0.033). Clinical response at earlier follow up points did not predict surgery- nor permanent ostomy-free survival.

Conclusion

These results support evidence that TNT may be a non-surgical option for select patients with rectal adenocarcinoma who desire organ preservation. In this investigation at a single institution, the treatment response on 6-month post-CRT endoscopy was the best predictor of surgery- and permanent ostomy-free survival, which are outcomes that are important to patient quality of life. CRT followed by consolidation chemotherapy was associated with higher rates of cCR and lower rates of surgery compared to those treated with induction chemotherapy.

Molecular subtypes of colorectal cancer in the era of precision oncotherapy: Current inspirations and future challenges

BACKGROUND

Colorectal cancer (CRC) is among the most hackneyed malignancies. Even patients with identical clinical symptoms and the same TNM stage still exhibit radically different clinical outcomes after receiving equivalent treatment regimens, indicating extensive heterogeneity of CRC. Myriad molecular subtypes of CRC have been exploited for decades, including the most compelling consensus molecular subtype (CMS) classification that has been broadly applied for patient stratification and biomarker-drug combination formulation. Encountering barriers to clinical translation, however, CMS classification fails to fully reflect inter- or intra-tumor heterogeneity of CRC. As a consequence, addressing heterogeneity and precisely managing CRC patients with unique characteristics remain arduous tasks for clinicians.

REVIEW

In this review, we systematically summarize molecular subtypes of CRC and further elaborate on their clinical applications, limitations, and future orientations.

CONCLUSION

In recent years, exploration of subtypes through cell lines, animal models, patient-derived xenografts (PDXs), organoids, and clinical trials contributes to refining biological insights and unraveling subtype-specific therapies in CRC. Therapeutic interventions including nanotechnology, clustered regulatory interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9), gut microbiome, and liquid biopsy are powerful tools with the possibility to shift the immunologic landscape and outlook for CRC precise medicine.

Prognostic analysis of Yes-associated protein 1 in patients with colorectal cancer. A systematic review and meta-analysis

BACKGROUND

colorectal cancer (CRC) is the most common carcinoma worldwide, but a lack of effective prognostic markers limits clinical diagnosis and treatment. Yes-associated protein 1 (YAP1) is an effector of the HIPPO-pathway, which plays a critical role in cancer development and prognosis, including CRC. However, previous reports have suggested that it plays a dual role in CRC.

METHODS

a meta-analysis using RevMan 5.4 and Stata 14.0 was performed to evaluate the relationship between YAP1 and clinical outcomes of CRC, after searching for eligible studies in the PubMed, Web of Science and Embase databases. Online datasets GEPIA and LOGpc were also used to calculate survival results and for comparison with the meta-analysis results. Besides, "DESeq" packages were used for the expression analysis of YAP1 from the TCGA dataset.

RESULTS

YAP1 was overexpressed in the cancer tissues when compared to normal tissues in patients with CRC from the TCGA database (p = 0.000164) and GEPIA database. A total of 10 studies involving 2305 patients from the literature were selected. Pooled HR indicated that overexpression of YAP1 was associated with poor clinical outcomes (HR = 1.70, 95 % CI: 1.28-2.26, p = 0.0003). Subgroup analysis showed a clear correlation between overexpression of YAP1 and worse survival rate in Chinese patients (HR = 1.94, 95 % CI: 1.40-2.69, p = 0.0001), nuclear YAP1 overexpression (HR = 2.07, 95 % CI: 1.29-3.31, p = 0.003), 60 months of follow-up (HR = 1.89, 95 % CI: 1.30-2.73, p = 0.0008), IHC test (HR = 1.65, 95 % CI: 1.17-2.33, p = 0.005), IHC combined with other tests (HR = 1.77, 95 % CI: 1.13-2.77, p = 0.01) and multivariate analysis (HR = 1.70, 95 % CI: 1.24-2.31, p = 0.0009). Nevertheless, disease-free survival (DFS) showed no significant results in the patients with CRC in our meta-analysis (HR = 1.38, 95 % CI: 0.51-3.75, p = 0.52) as well as in the GEPIA and LOGpc databases. Meanwhile, YAP1 overexpression was also significantly associated with worse overall survival (OS) in GSE17536, GSE40967, GSE29623 and GSE71187.

CONCLUSION

YAP1 overexpression is common in CRC tissues. Overexpression of YAP1 in CRC patients, particularly in the nucleus, might be related to shorter OS, maybe in the early stages. YAP1 could serve as a potential predictor of poor prognosis in CRC.

Clinical value of folate receptor-positive circulating tumor cells in patients with esophageal squamous cell carcinomas: a retrospective study

BACKGROUND

The aim of the study is to explore the role of preoperative folate receptor-positive circulating tumor cell (FR+CTC) levels in predicting disease-free survival (DFS) and overall survival (OS) in patients with esophageal squamous cell carcinomas (ESCC).

METHODS

Three ml blood samples were prospectively drawn from ESCC patients, and ligand-targeted polymerase chain reaction (LT-PCR) was used for the quantification of FR+CTCs. Other serum indicators were measured by traditional methods. Clinicopathological characteristics were obtained from the hospital medical record system, DFS and OS data were obtained by follow-up. The correlation between clinico-pathological characteristics, DFS, and OS and FR+CTCs were analyzed, respectively. Risk factors potentially affecting DFS and OS were explored by Cox regression analysis.

RESULTS

there were no significant correlations between FR+CTCs and patient age, sex, albumin, pre-albumin, C-reactive protein (CRP), ferritin and CRP/Albumin ratio, tumor size, grade of differentiation, lymph node metastasis, TNM stage, perineural invasion/vessel invasion (all P > 0.05). Nevertheless, preoperative FR+CTCs were an independent prognostic factor for DFS (HR 2.7; 95% CI 1.31-, P = 0.007) and OS (HR 3.37; 95% CI 1.06-, P = 0.04). DFS was significantly shorter for patients with post-operative FR+CTCs ≥ 17.42 FU/3ml compared with patients < 17.42 FU/3ml (P = 0.0012). For OS, it was shorter for patients with FR+CTCs ≥ 17.42 FU/3ml compared with patients < 17.42 FU/3ml, however, the difference did not reach statistical significance (P = 0.51).

CONCLUSIONS

ESCC patients with high FR+CTCs tend to have a worse prognosis. FR+CTCs may monitor the recurrence of cancers in time, accurately assess patient prognosis, and guide clinical decision-making.

TRIAL REGISTRATION

The study was approved by the Sichuan Cancer Hospital & Institute Ethics Committee (No. SCCHEC-02-2022-050).

Updated Management of Colorectal Cancer Liver Metastases: Scientific Advances Driving Modern Therapeutic Innovations

Colorectal cancer is the second leading cause of cancer-related deaths in the United States and accounts for an estimated 1 million deaths annually worldwide. The liver is the most common site of metastatic spread from colorectal cancer, significantly driving both morbidity and mortality. Although remarkable advances have been made in recent years in the management for patients with colorectal cancer liver metastases, significant challenges remain in early detection, prevention of progression and recurrence, and in the development of more effective therapeutics. In 2017, our group held a multidisciplinary state-of-the-science symposium to discuss the rapidly evolving clinical and scientific advances in the field of colorectal liver metastases, including novel early detection and prognostic liquid biomarkers, identification of high-risk cohorts, advances in tumor-immune therapy, and different regional and systemic therapeutic strategies. Since that time, there have been scientific discoveries translating into therapeutic innovations addressing the current management challenges. These innovations are currently reshaping the treatment paradigms and spurring further scientific discovery. Herein, we present an updated discussion of both the scientific and clinical advances and future directions in the management of colorectal liver metastases, including adoptive T-cell therapies, novel blood-based biomarkers, and the role of the tumor microbiome. In addition, we provide a comprehensive overview detailing the role of modern multidisciplinary clinical approaches used in the management of patients with colorectal liver metastases, including considerations toward specific molecular tumor profiles identified on next generation sequencing, as well as quality of life implications for these innovative treatments.

Raman Spectroscopy Combined with Malaria Protein for Early Capture and Recognition of Broad-Spectrum Circulating Tumor Cells

Early identification of tumors can significantly reduce the mortality rate. Circulating tumor cells (CTCs) are a type of tumor cell that detaches from the primary tumor and circulates through the bloodstream. Monitoring CTCs may allow the early identification of tumor progression. However, due to their rarity and heterogeneity, the enrichment and identification of CTCs is still challenging. Studies have shown that Raman spectroscopy could distinguish CTCs from metastatic cancer patients. VAR2CSA, a class of malaria proteins, has a strong broad-spectrum binding effect on various tumor cells and is a promising candidate biomarker for cancer detection. Here, recombinant malaria VAR2CSA proteins were synthesized, expressed, and purified. After confirming that various types of tumor cells can be isolated from blood by recombinant malaria VAR2CSA proteins, we further proved that the VAR2CSA combined with Raman spectroscopy could be used efficiently for tumor capture and type recognition using A549 cell lines spiked into the blood. This would allow the early screening and detection of a broad spectrum of CTCs. Finally, we synthesized and purified the malaria protein fusion antibody and confirmed its in vitro tumor-killing activity. Herein, this paper exploits the theoretical basis of a novel strategy to capture, recognize, and kill broad-spectrum types of CTCs from the peripheral blood.

Targeting HDAC2-Mediated Immune Regulation to Overcome Therapeutic Resistance in Mutant Colorectal Cancer

A large body of clinical and experimental evidence indicates that colorectal cancer is one of the most common multifactorial diseases. Although some useful prognostic biomarkers for clinical therapy have already been identified, it is still difficult to characterize a therapeutic signature that is able to define the most appropriate treatment. Gene expression levels of the epigenetic regulator histone deacetylase 2 (HDAC2) are deregulated in colorectal cancer, and this deregulation is tightly associated with immune dysfunction. By interrogating bioinformatic databases, we identified patients who presented simultaneous alterations in HDAC2, class II major histocompatibility complex transactivator (CIITA), and beta-2 microglobulin (B2M) genes based on mutation levels, structural variants, and RNA expression levels. We found that B2M plays an important role in these alterations and that mutations in this gene are potentially oncogenic. The dysregulated mRNA expression levels of HDAC2 were reported in about 5% of the profiled patients, while other specific alterations were described for CIITA. By analyzing immune infiltrates, we then identified correlations among these three genes in colorectal cancer patients and differential infiltration levels of genetic variants, suggesting that HDAC2 may have an indirect immune-related role in specific subgroups of immune infiltrates. Using this approach to carry out extensive immunological signature studies could provide further clinical information that is relevant to more resistant forms of colorectal cancer.

MiSelect R System: the validation of a new detection system of CTCs and their correlation with prognosis in non-metastatic CRC patients

Circulating tumor cells (CTCs) in blood are accepted as a prognostic marker for patients with metastatic colorectal cancer (CRC). However, there is limited data on the use of CTCs as a prognostic marker for non-metastatic patients. In the current study, we used a rare cell automated analysis platform, the MiSelect R System, to enumerate CTCs from blood in non-metastatic CRC patients, and corelated the number of CTCs with the clinical staging and survival. The presence of CTCs in mesenteric vein blood (MVB) samples from 101 CRC patients was significantly associated with T stage. Patients with 1 or more CTCs per 8 mL of MVB exhibited significantly worse disease-free survival (DFS) and cancer-specific survival (CSS) compared to patient without CTCs. The presence of CTCs before surgery is an independent marker for both DFS and CSS. CTC presence after surgical resection is also a prognostic marker. CTCs are a potentially useful prognostic and predictive biomarker in non-metastatic CRC patients that may further stratify patient's risk status within different stages of disease.

Current Applications of Liquid Biopsy in Gastrointestinal Cancer Disease-From Early Cancer Detection to Individualized Cancer Treatment

Worldwide, gastrointestinal (GI) cancers account for a significant amount of cancer-related mortality. Tests that allow an early diagnosis could lead to an improvement in patient survival. Liquid biopsies (LBs) due to their non-invasive nature as well as low risk are the current focus of cancer research and could be a promising tool for early cancer detection. LB involves the sampling of any biological fluid (e.g., blood, urine, saliva) to enrich and analyze the tumor's biological material. LBs can detect tumor-associated components such as circulating tumor DNA (ctDNA), extracellular vesicles (EVs), and circulating tumor cells (CTCs). These components can reflect the status of the disease and can facilitate clinical decisions. LBs offer a unique and new way to assess cancers at all stages of treatment, from cancer screenings to prognosis to management of multidisciplinary therapies. In this review, we will provide insights into the current status of the various types of LBs enabling early detection and monitoring of GI cancers and their use in in vitro diagnostics.

Reconstruction of the tumor spatial microenvironment along the malignant-boundary-nonmalignant axis

Although advances in spatial transcriptomics (ST) enlarge to unveil spatial landscape of tissues, it remains challenging to delineate pathology-relevant and cellular localizations, and interactions exclusive to a spatial niche (e.g., tumor boundary). Here, we develop Cottrazm, integrating ST with hematoxylin and eosin histological image, and single-cell transcriptomics to delineate the tumor boundary connecting malignant and non-malignant cell spots in tumor tissues, deconvolute cell-type composition at spatial location, and reconstruct cell type-specific gene expression profiles at sub-spot level. We validate the performance of Cottrazm along the malignant-boundary-nonmalignant spatial axis. We identify specific macrophage and fibroblast subtypes localized around tumor boundary that interacted with tumor cells to generate a structural boundary, which limits T cell infiltration and promotes immune exclusion in tumor microenvironment. In this work, Cottrazm provides an integrated tool framework to dissect the tumor spatial microenvironment and facilitates the discovery of functional biological insights, thereby identifying therapeutic targets in oncologic ST datasets.

Influence of Perioperative Anesthesia on Cancer Recurrence: from Basic Science to Clinical Practice

PURPOSEOF REVIEW

In this review, we will summarize the effects of these perioperative anesthetics and anesthetic interventions on the immune system and tumorigenesis as well as address the related clinical evidence on cancer-related mortality and recurrence.

RECENT FINDINGS

Cancer remains a leading cause of morbidity and mortality worldwide. For many solid tumors, surgery is one of the major therapies. Unfortunately, surgery promotes angiogenesis, shedding of circulating cancer cells, and suppresses immunity. Hence, the perioperative period has a close relationship with cancer metastases or recurrence. In the perioperative period, patients require multiple anesthetic management including anesthetics, anesthetic techniques, and body temperature control. Preclinical and retrospective studies have found that these anesthetic agents and interventions have complex effects on cancer outcomes. Therefore, well-planned, prospective, randomized controlled trials are required to explore the effects of different anesthetics and techniques on long-term outcomes after cancer surgery. Due to the conflicting effects of anesthetic management on cancer recurrence, further preclinical and clinical trials are required and beneficial to the development of systemic cancer therapies.

Clinical Applications of Liquid Biopsy in Colorectal Cancer Screening: Current Challenges and Future Perspectives

Colorectal cancer (CRC) represents the third most prevalent cancer worldwide and a leading cause of mortality among the population of western countries. However, CRC is frequently a preventable malignancy due to various screening tests being available. While failing to obtain real-time data, current screening methods (either endoscopic or stool-based tests) also require disagreeable preparation protocols and tissue sampling through invasive procedures, rendering adherence to CRC screening programs suboptimal. In this context, the necessity for novel, less invasive biomarkers able to identify and assess cancer at an early stage is evident. Liquid biopsy comes as a promising minimally invasive diagnostic tool, able to provide comprehensive information on tumor heterogeneity and dynamics during carcinogenesis. This review focuses on the potential use of circulating tumor cells (CTCs), circulating nucleic acids (CNAs) and extracellular vesicles as emerging liquid biopsy markers with clinical application in the setting of CRC screening. The review also examines the opportunity to implement liquid biopsy analysis during everyday practice and provides highlights on clinical trials researching blood tests designed for early cancer diagnosis. Additionally, the review explores potential applications of liquid biopsies in the era of immunotherapy.

Where Are We Now and Where Might We Be Headed in Understanding and Managing Brain Metastases in Colorectal Cancer Patients?

OPINION STATEMENT

Compared to liver and lung metastases, brain metastases (BMs) from colorectal cancer (CRC) are rare and remain poorly investigated despite the anticipated rise in their incidence. CRC patients bearing BM have a dismal prognosis with a median survival of 3-6 months, significantly lower than that of patients with BM from other primary tumors, and of those with metastatic CRC manifesting extracranially. While liver and lung metastases from CRC have more codified treatment strategies, there is no consensus regarding the treatment of BM in CRC, and their management follows the approaches of BM from other solid tumors. Therapeutic strategies are driven by the number and localisation of the lesion, consisting in local treatments such as surgery, stereotactic radiosurgery, or whole-brain radiotherapy. Novel treatment modalities are slowly finding their way into this shy unconsented armatorium including immunotherapy, monoclonal antibodies, tyrosine kinase inhibitors, or a combination of those, among others.This article reviews the pioneering strategies aiming at understanding, diagnosing, and managing this disease, and discusses future directions, challenges, and potential innovations in each of these domains.

HIGHLIGHTS

• With the increasing survival in CRC, brain and other rare/late-onset metastases are rising. • Distal colon/rectal primary location, long-standing progressive lung metastases, and longer survival are risk factors for BM development in CRC. • Late diagnosis and lack of consensus treatment strategies make BM-CRC diagnosis very dismal. • Liquid biopsies using circulating tumor cells might offer excellent opportunities in the early diagnosis of BM-CRC and the search for therapeutic options. • Multi-modality treatment including surgical metastatic resection, postoperative SRS with/without WBRT, and chemotherapy is the best current treatment option. • Recent mid-sized clinical trials, case reports, and preclinical models show the potential of unconventional therapeutic approaches as monoclonal antibodies, targeted therapies, and immunotherapy. Graphical abstract.

The current state of molecular profiling in gastrointestinal malignancies

This is a review of the current state of molecular profiling in gastrointestinal (GI) cancers and what to expect from this evolving field in the future. Individualized medicine is moving from broad panel testing of numerous genes or gene products in tumor biopsy samples, identifying biomarkers of prognosis and treatment response, to relatively noninvasive liquid biopsy assays, building on what we have learned in our tumor analysis and growing into its own evolving predictive and prognostic subspecialty. Hence, the field of GI precision oncology is exploding, and this review endeavors to summarize where we are now in preparation for the journey ahead.

Circular RNA circ_0065378 upregulates tumor suppressor candidate 1 by competitively binding with miR-4701-5p to alleviate colorectal cancer progression

BACKGROUND AND AIM

Colorectal cancer (CRC), the third most lethal human cancer worldwide, seriously threatens human health and life. Numerous circular RNAs (circRNAs) including circ_PLXNB1 (hsa_circ_0065378) have been confirmed to be dysregulated in CRC by RNA-seq analysis. We aimed to explore the functional role of circ_PLXNB1 in CRC malignant behaviors and clarify its potential molecular mechanism.

METHODS

Gene expression levels of circ_PLXNB1 and miR-4701-5p were determined by quantitative real-time polymerase chain reaction analysis. MTT and Transwell assays were conducted to measure cell proliferation, invasion, and migration. Protein expression of tumor suppressor candidate 1 (TUSC1), E-cadherin and N-cadherin was determined by western blot analysis. Mouse xenograft models were used to investigate the role of circ_PLXNB1 in tumor growth.

RESULTS

The results showed that gene expression of circ_PLXNB1 in CRC tissues was significantly downregulated. Overexpression of circ_PLXNB1 inhibited the malignant behaviors of CRC cells, as manifested by the decrease in cell proliferation, cell invasion, migration, and EMT. Mechanistically, circ_PLXNB1 exerted its functional effects by binding with miR-4701-5p. Moreover, TUSC1 siRNA partially abolished the suppressive effect of the miR-4701-5p inhibitor or circ_PLXNB1 on CRC cell malignant behaviors.

CONCLUSIONS

Circ_PLXNB1 attenuated CRC progression by binding with miR-4701-5p to overexpress TUSC1, indicating that the circ_PLXNB1/miR-4701-5p/TUSC1 axis might be a potential novel molecular target in CRC diagnosis and therapy.

Liquid Biopsy: A Distinctive Approach to the Diagnosis and Prognosis of Cancer

Cancer is a leading cause of morbidity and mortality worldwide. Over the past decades, the concept of precision cancer medicine has emerged as a novel approach in the field of oncology that aims to tailor the most effective treatment options to each individual cancer patient based on the genetic profile of the tumor of each individual patient. Recently, tissue biopsy has become an essential part of cancer care and is widely used to characterize the tumor. However, tissue biopsy techniques face different challenges due to their invasiveness, cost, time, and adversity in potential sampling due to tissue heterogeneity. To overcome these issues, a non-invasive approach has developed, which is known as liquid biopsy. It is a simple, fast, and worthwhile technique based on the analysis of circulating tumor DNA (which is a fraction of cfDNA), circulating tumor cells (CTCs), and other tumor-derived material in blood plasma. This review provides an overview of the concept of liquid biopsy and briefly discusses the role of ctDNA and CTC analysis as tools for early diagnosis and prognosis of cancer. In this review, we also speculate on the advantages of liquid biopsy as opposed to tissue biopsy and postulate that liquid biopsy may be a comprehensive approach to overcome the current limitations associated with costly, invasive, and time-consuming tissue biopsy.

Protective effects of physical activity in colon cancer and underlying mechanisms: A review of epidemiological and biological evidence

Numerous epidemiological studies indicate that physical activity has a protective effect against colon cancer development and progression. Further, the relevant biological mechanisms where physical activity or exercise may improve survival have also been initially examined. In this review, we provide an overview of the epidemiological evidence to date which comprises 16 cohort studies of the effects of physical activity on colon cancer outcomes including cancer recurrence, cancer-specific and overall survival. Moreover, we present four potential mechanisms involving shear pressure, systemic milieu alteration, extracellular vesicles, and immune function by which physical activity and exercise may favorably impact colon cancer. Research currently in progress will provide definitive evidence of survival benefits resulting from exercise and future work will help clarify the role of targeted exercise and the relevant mechanisms involved.

Clinical significance of circulating tumour cells and tumour marker detection in the chemotherapeutic evaluation of advanced colorectal cancer

AIM

Systemic chemotherapy combining biological targeted therapies is the standard therapy for patients with metastatic colorectal cancer (mCRC), but effective markers are needed to identify clinical responders. Circulating tumour cells (CTCs) have been associated with prognosis in patients with mCRC. This study aimed to explore the relationship between CTC number and the clinical response of patients with advanced CRC.

METHOD

Epithelial cell adhesion molecule-independent enrichment and CD45^- fluorescence in situ hybridization immunofluorescence were used to detect peripheral blood CTCs in 79 patients with advanced CRC. Fisher's exact test and Spearman's rank correlation coefficient were used to analyse the correlation between CTC number and efficacy of chemotherapy. Kaplan-Meier and Cox regression analyses were used to evaluate progression-free survival (PFS).

RESULTS

Among the evaluable patients, CTCs were significantly correlated with clinical response (r =4.891, p = 0.031). High CTC numbers were associated with a poor treatment response (r = -0.250, p = 0.027). Dynamic decrease in CTC number was associated with clinical response (p = 0.046). High baseline CTC number and carcinoembryonic antigen levels were prognostic factors for unfavourable PFS in multivariable analysis [hazard ratio (HR) = 3.30, p = 0.011 and HR = 2.04, p = 0.044, respectively]. Compared with the CTC-positive group, the CTC-negative group showed superior PFS (median PFS 15.53 vs. 9.43 months, p = 0.041) among CRC patients receiving first-line treatment.

CONCLUSION

CTC number is a feasible biomarker for predicting outcomes in mCRC patients receiving systemic chemotherapy.

Diagnostic Impact of Radiological Findings and Extracellular Vesicles: Are We Close to Radiovesicolomics?

Simple Summary

Over the years, diagnostic tests such as in radiology and flow cytometry have become more and more powerful in the constant struggle against different pathologies, some of which are life-threatening. The possibility of using these “weapons” in a conjugated manner could result in higher healing and prevention rates, and a decrease in late diagnosis diseases. Different correlations among pathologies, extracellular vesicles (EVs), and radiological findings were recently demonstrated by many authors. Together with the increasing importance of “omics” sciences, and artificial intelligence in this new century, the perspective of a new research field called “radiovesicolomics” could be the missing link, enabling a different approach to disease diagnosis and treatment.

Abstract

Currently, several pathologies have corresponding and specific diagnostic and therapeutic branches of interest focused on early and correct detection, as well as the best therapeutic approach. Radiology never ceases to develop newer technologies in order to give patients a clear, safe, early, and precise diagnosis; furthermore, in the last few years diagnostic imaging panoramas have been extended to the field of artificial intelligence (AI) and machine learning. On the other hand, clinical and laboratory tests, like flow cytometry and the techniques found in the “omics” sciences, aim to detect microscopic elements, like extracellular vesicles, with the highest specificity and sensibility for disease detection. If these scientific branches started to cooperate, playing a conjugated role in pathology diagnosis, what could be the results? Our review seeks to give a quick overview of recent state of the art research which investigates correlations between extracellular vesicles and the known radiological features useful for diagnosis.

Liquid Biopsy-Based Colorectal Cancer Screening via Surface Markers of Circulating Tumor Cells

Colorectal cancer (CRC) is ranked second for cancer-related deaths worldwide with approximately half of the patients being diagnosed at the late stages. The untimely detection of CRC results in advancement to the metastatic stage and nearly 90% of cancer-related deaths. The early detection of CRC is crucial to decrease its overall incidence and mortality rates. The recent introduction of circulating tumor cells (CTCs) has enabled a less invasive sampling method from liquid biopsies, besides revealing key information toward CRC metastasis. The current gold standard for CTC identification is the CellSearch® system (Veridex). This first-generation instrumentation relies on a single cell surface marker (CSM) to capture and count CTCs. Detection of CTCs allows the identification of patients at risk for metastasis, whereas CTC enumeration could improve risk assessment, monitoring of systemic therapy, and detection of therapy resistance in advanced metastatic CRC. In this review, we compared the pros and cons between single CSM-based CTC enrichment techniques and multi-marker-based systems. We also highlighted the challenges faced in the routine implementation of CSM-dependent CTC detection methods in CRC screening, prediction, prognosis, disease monitoring, and therapy selection toward precision medicine, as well as the dwelling on post-CTC analysis and characterization methods.

Role of Phenotypes of Circulating Tumor Cells in the Diagnosis and Treatment of Colorectal Cancer

OBJECTIVE

To investigate the relationship between circulating tumor cells (CTCs) and their subpopulations and colorectal cancer (CRC). To explore the application of CTCs' numbers and positive rates in the diagnosis and treatment of CRC, and to assess the effect of surgery on CTCs numbers and positivity.

METHODS

We identified CTCs using the CanPatrol technique after enrollment. Peripheral blood samples were collected from 74 CRC patients before anti-tumor treatment. CTCs can be divided into the following three phenotypes: epithelial CTCs (E-CTCs) (EpCAM+, Vimentin-), mesenchymal CTCs (M-CTCs) (EpCAM-, Vimentin+), and mixed CTCs (E/M-CTCs) (EpCAM+, Vimentin+). CTCs and the proportion of subtypes were statistically compared with clinicopathological characteristics.

RESULTS

The positive rate of M-CTCs was significantly higher in patients with tumor size ≥5 cm (85.7% vs 49.1%, P = 0.004) and carcinoembryonic antigen (CEA) >5 ng/mL (83.3% vs 51.0% p = 0.024). Moreover, the T stage (T1 0, T2 33.3%, T3 59.4%, T4 100%, p < 0.0005) and TNM stage (stage I 11.8%, stage II 79.2%, stage III 64.3%, stage IV 100%, p < 0.0005) were correlated with the positive rate of M-CTCs. We also found that the proportion of M-CTCs was correlated with the T stage (p < 0.0005) and TNM stage (p=0.0200), but not with the N stage (p=0.6889). In survival analysis, M-CTCs >1 were found associated with worse disease-free survival (p=0.007). After treatment, the number and proportion of CTCs and M-CTCs were significantly reduced.

CONCLUSION

The positive rate of M-CTCs was associated with tumor size, T stage, TNM stage, vascular invasion, and CEA. As the disease progressed, the proportion of M-CTCs gradually increased, and the survival performance was worse in patients with a high positive rate of M-CTCs.

Single-cell nucleic acid profiling in droplets (SNAPD) enables high-throughput analysis of heterogeneous cell populations

Experimental methods that capture the individual properties of single cells are revealing the key role of cell-to-cell variability in countless biological processes. These single-cell methods are becoming increasingly important across the life sciences in fields such as immunology, regenerative medicine and cancer biology. In addition to high-dimensional transcriptomic techniques such as single-cell RNA sequencing, there is a need for fast, simple and high-throughput assays to enumerate cell samples based on RNA biomarkers. In this work, we present single-cell nucleic acid profiling in droplets (SNAPD) to analyze sets of transcriptional markers in tens of thousands of single mammalian cells. Individual cells are encapsulated in aqueous droplets on a microfluidic chip and the RNA markers in each cell are amplified. Molecular logic circuits then integrate these amplicons to categorize cells based on the transcriptional markers and produce a detectable fluorescence output. SNAPD is capable of analyzing over 100,000 cells per hour and can be used to quantify distinct cell types within heterogeneous populations, detect rare cells at frequencies down to 0.1% and enrich specific cell types using microfluidic sorting. SNAPD provides a simple, rapid, low cost and scalable approach to study complex phenotypes in heterogeneous cell populations.

Clinical utility of circulating tumor cells: an update

The prognostic role of circulating tumor cells (CTCs) has been clearly demonstrated in many types of cancer. However, their roles in diagnostic and treatment strategies remain to be defined. In this review, we present an overview of the current clinical validity of CTCs in nonmetastatic and metastatic cancer, and the main studies or concepts investigating the clinical utility of CTCs. In particular, we focus on breast, lung, colorectal, and prostate cancer. Two major topics concerning the clinical utility of CTC are discussed: treatment based on CTC count or CTC variations, and treatment based on the molecular characteristics of CTCs. Although some of these studies are inconclusive, many are still ongoing, and their results could help to define the role of CTCs in the management of cancers. A summary of published or ongoing phase II-III trials is also presented.

Enhancing Prediction Performance by Add-On Combining Circulating Tumor Cell Count, CD45neg EpCAMneg Cell Count on Colorectal Cancer, Advance, and Metastasis

Simple Summary

Information describing circulating tumor cells (CTCs) holds promise for clinical applications. However, conventional CTCs enumeration could ignore the CTCs more relevant to cancer metastasis. Thus, negative selection CTC enumeration was proposed, by which information on the numbers of CTCs and CD45^neg EpCAM^neg cells can be obtained. By combining this approach with the conventional biomarker carcinoembryonic antigen (CEA), this study aimed to explore whether any combination of these biomarkers could improve the predictive performance for colorectal cancer (CRC) or its status. Results revealed that a combination of the two cell populations showed improved performance (AUROC: 0.893) for CRC prediction over the use of only one population. Compared with CEA alone, the combination of the three biomarkers increased the performance (AUROC) for advanced CRC prediction from 0.643 to 0.727. Compared with that of CEA alone for metastatic CRC prediction, the AUROC was increased from 0.780 to 0.837 when the CTC count was included.

Abstract

Conventional circulating tumor cell (CTC) enumeration could ignore the CTCs more relevant to cancer metastasis. Thus, negative selection CTC enumeration was proposed, by which information on two cellular biomarkers (numbers of CTCs and CD45^neg EpCAM^neg cells) can be obtained. By combining this approach with the conventional biomarker carcinoembryonic antigen (CEA), this study aimed to explore whether any combination of these biomarkers could improve the predictive performance for colorectal cancer (CRC) or its status. In this work, these two cell populations in healthy donors and CRC patients were quantified. Results revealed that enumeration of these two cell populations was able to discriminate healthy donors from CRC patients, even patients with non-advanced CRC. Moreover, the combination of the two cell populations showed improved performance (AUROC: 0.893) for CRC prediction over the use of only one population. Compared with CEA alone, the combination of the three biomarkers increased the performance (AUROC) for advanced CRC prediction from 0.643 to 0.727. Compared with that of CEA alone for metastatic CRC prediction, the AUROC was increased from 0.780 to 0.837 when the CTC count was included. Overall, this study demonstrated that the combination of these two cellular biomarkers with CEA improved the predictive performance for CRC and its status.

Combined detection of circulating tumor cells, α-fetoprotein heterogene-3 and α-fetoprotein in the early diagnosis of HCC for the prediction of efficacy, prognosis, recurrence after microwave ablation

BACKGROUND

Early diagnosis can significantly improve treatment outcomes for hepatocellular carcinoma (HCC) patients. Currently, the dosage of serum alpha fetoprotein (AFP) is widely used in the diagnosis of HCC, but this biomarker has low specificity and may cause false positive or false negative results. Thus, it's necessary to find and validate other serum tumor markers that in association for AFP would increase the sensitivity and the specificity in the HCC diagnosis. This study investigated the predictive value of combined of AFP, AFP-L3, and Circulating tumor cells (CTCs).

METHODS

A total of 105 patients with HCC after microwave ablation (MWA) were divided into non recurrence group, recurrence group, good prognosis (CR + PR group, CR: Complete remission, PR: Partial remission) and poor prognosis (SD + PD group, SD: Stable, PD: Progression). ROC curve was used to analyze the short-term efficacy, prognosis and clinical value of combined detection of the three indicators in predicting postoperative recurrence of HCC patients with MWA.

RESULTS

The positive rate of serum CTCs, AFP-L3 and AFP combined detection in the diagnosis of HCC is higher than that of single index and two index detection. The AUC, sensitivity and specificity of serum CTCs, AFP-L3 and AFP combined detection was better than that of single index and two indexes in patients with HCC after MWA.

CONCLUSIONS

Combined detection of AFP, AFP-L3, and CTCs can effectively make up for the shortcomings of the detection with single and pairwise indicators. It can't only diagnose HCC in early, but also has a high clinical value of predicting the short-term efficacy, prognosis and recurrence of HCC patients after MWA treatment.

Profiling Colorectal Cancer in the Landscape Personalized Testing-Advantages of Liquid Biopsy

Drug-specific therapeutic approaches for colorectal cancer (CRC) have contributed to significant improvements in patient health. Nevertheless, there is still a great need to improve the personalization of treatments based on genetic and epigenetic tumor profiles to maximize the quality and efficacy while limiting cytotoxicity. Currently, CEA and CA 19-9 are the only validated blood biomarkers in clinical practice. For this reason, laboratories are trying to identify new specific prognostics and, more importantly, predictive biomarkers for CRC patient profiling. Thus, the unique landscape of personalized biomarker data should have a clinical impact on CRC treatment strategies and molecular genetic screening tests should become the standard method for diagnosing CRC. This review concentrates on recent molecular testing in CRC and discusses the potential modifications in CRC assay methodology with the upcoming clinical application of novel genomic approaches. While mechanisms for analyzing circulating tumor DNA have been proven too inaccurate, detecting and analyzing circulating tumor cells and protein analysis of exosomes represent more promising options. Blood liquid biopsy offers good prospects for the future if the results align with pathologists’ tissue analyses. Overall, early detection, accurate diagnosis and treatment monitoring for CRC with specific markers and targeted molecular testing may benefit many patients.

High cytoplasmic YAP1 expression predicts a poor prognosis in patients with colorectal cancer

Purpose

Yes associated protein 1 (YAP1), which is a standout amongst the most essential effectors of the Hippo pathway, assumes a vital part in a few kinds of cancer. However, whether YAP1 is an oncogene in CRC (colorectal cancer) remains controversial, and the association between the subcellular localization of YAP1 and clinical implications in CRC remains unknown.

Patients and methods

In this study, we investigated the subcellular localization of YAP1 in CRC cells by immunohistochemistry and then associate these findings with clinical information in a large CRC cohort with 919 CRC patients.

Results

The results show that CRC tissues has a significant higher expression of cytoplasmic YAP1 compared to adjacent normal tissues (all P < 0.001). Cytoplasmic YAP1 expression was significantly associated with the number of lymph nodes removed and differentiation grade (all P < 0.001). Furthermore, after correcting confounding variables, for example, TNM stage and differentiation grade, the multivariate Cox analysis confirmed cytoplasmic YAP1-high subgroup had a significant shorter DFS (HR = 3.255; 95% CI [2.290-4.627]; P < 0.001) and DSS (HR = 4.049; 95% CI [2.400-6.830]; P < 0.001) than cytoplasmic YAP1-low subgroup. High cytoplasmic YAP1 expression is associated with a worse survival in stage III CRC patients who received chemotherapy.

Conclusion

Cytoplasmic YAP1 could be could be utilized as a prognosis factor in CRC patients, and may be an indicator of whether certain patients population could benefit from postoperative chemotherapy.

Circulating tumor cell enumeration for improved screening and disease detection of patients with colorectal cancer

Background

The immunochemical fecal occult blood test (iFOBT) for colorectal cancer (CRC) screening and the serum carcinoembryonic antigen (CEA) assay for disease detection of CRC is associated with a high false-positive rate and a low detection sensitivity, respectively. There is an unmet need to define additional modalities to complement these assays. Different subsets of circulating tumor cells (CTCs) are present in the peripheral blood of cancer patients. Whether or not CTCs testing supplements these clinical assays and is valuable for patients with CRC was investigated.

Methods

CTCs were enriched from pre-operative patients with CRC (n = 109) and the non-cancerous controls (n = 65). CTCs expressing either epithelial cell adhesion molecule (EpCAM) or podoplanin (PDPN, the marker associated with poor cancer prognosis) were defined by immunofluorescence staining and were analyzed alone or in combination with iFOBT or serum CEA.

Results

Patients with early or advanced stage of CRC can be clearly identified and differentiated from the non-cancerous controls (p < 0.001) by EpCAM⁺-CTC or PDPN⁺-CTC count. The sensitivity and specificity of EpCAM⁺-CTCs was 85.3% and 78.5%, respectively, when the cutoff value was 23 EpCAM⁺-CTCs/mL of blood; and the sensitivity and specificity of PDPN⁺-CTCs was 78.0% and 75.4%, respectively, when the cutoff value was 7 PDPN⁺-CTCs/mL of blood. Combined analysis of iFOBT with the EpCAM⁺-CTC and PDPN⁺-CTC count reduced the false-positive rate of iFOBT from 56.3% to 18.8% and 23.4%, respectively. Combined analysis of serum CEA with the EpCAM⁺-CTC and PDPN⁺-CTC count increased the disease detection rate from 30.3% to 89.9% and 86.2%, respectively.

Conclusion

CTC testing could supplement iFOBT to improve CRC screening and supplement serum CEA assay for better disease detection of patients with CRC.

Biomarkers in Colorectal Cancer: Current Research and Future Prospects

Colorectal cancer (CRC) is a leading cause of death worldwide, despite progress made in detection and management through surgery, chemotherapy, radiotherapy, and immunotherapy. Novel therapeutic agents have improved survival in both the adjuvant and advanced disease settings, albeit with an increased risk of toxicity and cost. However, metastatic disease continues to have a poor long-term prognosis and significant challenges remain due to late stage diagnosis and treatment failure. Biomarkers are a key tool in early detection, prognostication, survival, and predicting treatment response. The past three decades have seen advances in genomics and molecular pathology of cancer biomarkers, allowing for greater individualization of therapy with a positive impact on survival outcomes. Clinically useful predictive biomarkers aid clinical decision making, such as the presence of KRAS gene mutations predicting benefit from epidermal growth factor receptor (EGFR) inhibiting antibodies. However, few biomarkers have been translated into clinical practice highlighting the need for further investigation. We review a range of protein, DNA and RNA-based biomarkers under investigation for diagnostic, predictive, and prognostic properties for CRC. In particular, long non-coding RNAs (lncRNA), have been investigated as biomarkers in a range of cancers including colorectal cancer. Specifically, we evaluate the potential role of lncRNA plasmacytoma variant translocation 1 (PVT1), an oncogene, as a diagnostic, prognostic, and therapeutic biomarker in colorectal cancer.

Potential theranostics of circulating tumor cells and tumor-derived exosomes application in colorectal cancer

Background

At the present time, colorectal cancer (CRC) is still known as a disease with a high mortality rate. Theranostics are flawless scenarios that link diagnosis with therapy, including precision medicine as a critical platform that relies on the development of biomarkers particularly “liquid biopsy”. Circulating tumor cells (CTCs) and tumor-derived exosomes (TDEs) in a liquid biopsy approach are of substantial importance in comparison with traditional ones, which cannot generally be performed to determine the dynamics of the tumor due to its wide restriction of range. Thus, recent attempts has shifted towards minimally noninvasive methods.

Main text

CTCs and TDEs, as significant signals emitted from the tumor microenvironment, which are also detectable in the blood, prove themselves to be promising novel biomarkers for cancer diagnosis, prognosis, and treatment response prediction. The therapeutic potential of them is still limited, and studies are at its infancy. One of the major challenges for the implementation of CTCs and TDEs which are new trends in translational medicine is the development of isolation and characterization; a standardizable approach. This review highlights and discusses the current challenges to find the bio fluids application in CRC early detection and clinical management.

Conclusion

Taken together, CTCs and TDEs as silent drivers of metastasis can serve in the management of cancer patient treatment and it is of the upmost importance to expand our insight into this subject. However, due to the limited data available from clinical trials, further validations are required before addressing their putative application in oncology.

Tumor circulome in the liquid biopsies for digestive tract cancer diagnosis and prognosis

Digestive tract cancer is one of the main diseases that endanger human health. At present, the early diagnosis of digestive tract tumors mainly depends on serology, imaging, endoscopy, and so on. Although tissue specimens are the gold standard for cancer diagnosis, with the rapid development of precision medicine in cancer, the demand for dynamic monitoring of tumor molecular characteristics has increased. Liquid biopsy involves the collection of body fluids via non-invasive approaches, and analyzes biological markers such as circulating tumor cells, circulating tumor DNA, circulating cell-free DNA, microRNAs, and exosomes. In recent years, liquid biopsy has become more and more important in the diagnosis and prognosis of cancer in clinical practice due to its convenience, non-invasiveness, high specificity and it overcomes temporal-spatial heterogeneity. Therefore, this review summarizes the current evidence on liquid biopsies in digestive tract cancers in relation to diagnosis and prognosis.

Enabling Precision Oncology Through Precision Diagnostics

Genomic testing enables clinical management to be tailored to individual cancer patients based on the molecular alterations present within cancer cells. Genomic sequencing results can be applied to detect and classify cancer, predict prognosis, and target therapies. Next-generation sequencing has revolutionized the field of cancer genomics by enabling rapid and cost-effective sequencing of large portions of the genome. With this technology, precision oncology is quickly becoming a realized paradigm for managing the treatment of cancer patients. However, many challenges must be overcome to efficiently implement the transition of next-generation sequencing from research applications to routine clinical practice, including using specimens commonly available in the clinical setting; determining how to process, store, and manage large amounts of sequencing data; determining how to interpret and prioritize molecular findings; and coordinating health professionals from multiple disciplines.

Liquid Biopsy in Colorectal Carcinoma: Clinical Applications and Challenges

Colorectal carcinoma (CRC) is characterized by wide intratumor heterogeneity with general genomic instability and there is a need for improved diagnostic, prognostic, and therapeutic tools. The liquid biopsy provides a noninvasive route of sample collection for analysis of circulating tumor cells (CTCs) and genomic material, including cell-free DNA (cfDNA), as a complementary biopsy to the solid tumor tissue. The solid biopsy is critical for molecular characterization and diagnosis at the time of collection. The liquid biopsy has the advantage of longitudinal molecular characterization of the disease, which is crucial for precision medicine and patient-oriented treatment. In this review, we provide an overview of CRC and the different methodologies for the detection of CTCs and cfDNA, followed by a discussion on the potential clinical utility of the liquid biopsy in CRC patient care, and lastly, current challenges in the field.

Clinical significance of epithelial-mesenchymal transition typing of circulating tumour cells in colorectal cancer

AIM

The aim was to determine the diagnostic value of epithelial-mesenchymal transition typing of circulating tumour cells (CTCs) in colorectal cancer (CRC).

METHOD

Peripheral blood samples were collected from 51 CRC patients before anti-tumour treatment from April 2016 to June 2018 at the Peking University Shenzhen Hospital. The blood samples were analysed using the CanPatrol CTC typing technique (SurExam, Guangzhou, China), which combines nanomembrane enrichment with mRNA in situ hybridization. Based on the marker expression, the CTCs were classified into epithelial, epithelial mesenchymal and mesenchymal (M-CTC) types. The correlation between the CTC counts and clinicopathological characteristics such as gender, age, TNM stage, lymph node metastasis and distant metastasis were analysed by univariate and multivariate Cox regression models. The overall survival and progression-free survival (PFS) of patients demarcated by CTC typing were analysed using the Kaplan-Meier method and log-rank tests.

RESULT

M-CTCs were detected more frequently in patients with lymph node metastasis (N2 81.8%; N1 72.7%; N0 38.9%) as well as distant metastasis (M0 50%; M1a 81.25%; M1b 85.7%) compared to those without metastasis. In addition, the presence of M-CTCs was significantly correlated with distant metastasis (P < 0.01). Univariate analysis showed that lymph node metastasis (P = 0.035), distant metastasis (P < 0.001) and total CTC count ≥ 4 (P = 0.007) and M-CTC count ≥ 1 (P < 0.001) were significantly associated with unfavourable PFS, and lymph node metastasis (P = 0.04), distant metastasis (P = 0.01) and M-CTC count ≥ 1 (P < 0.001) were significantly associated with unfavourable overall survival. Multivariate analysis showed that the presence of M-CTCs was the only independent prognostic factor for poor PFS, and patients with M-CTCs had significantly shorter PFS than those without (P = 0.011).

CONCLUSION

M-CTCs are significantly associated with CRC severity and metastasis, and M-CTC count is an independent predictor of prognosis.

Perspectives of the Application of Liquid Biopsy in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors and the second leading cause of cancer death worldwide. Since traditional biopsies are invasive and do not reflect tumor heterogeneity or monitor the dynamic progression of tumors, there is an urgent need for new noninvasive methods that can supplement and improve the current management strategies of CRC. Blood-based liquid biopsies are a promising noninvasive biomarker that can detect disease early, assist in staging, monitor treatment responses, and predict relapse and metastasis. Over time, an increasing number of experiments have indicated the clinical utility of liquid biopsies in CRC. In this review, we mainly focus on the development of circulating tumor cells and circulating tumor DNA as key components of liquid biopsies in CRC and introduce the potential of exosomal microRNAs as emerging liquid biopsy markers in clinical application for CRC.

Extracellular vesicle-miRNAs as liquid biopsy biomarkers for disease identification and prognosis in metastatic colorectal cancer patients

Disseminated disease is present in ≈50% of colorectal cancer patients upon diagnosis, being responsible for most of cancer deaths. Addition of biological drugs, as Bevacizumab, to chemotherapy, has increased progression free survival and overall survival of metastatic colorectal cancer (mCRC) patients. However, these benefits have been only reported in a small proportion of patients. To date, there are not biomarkers that could explain the heterogeneity of this disease and would help in treatment selection. Recent findings demonstrated that microRNAs (miRNAs) play an important role in cancer and they can be encapsulated with high stability into extracellular vesicles (EVs) that are released in biological fluids. EVs can act as cell-to-cell communicators, transferring genetic information, such as miRNAs. In this context, we aimed to investigate serum EV associated miRNAs (EV-miRNAs) as novel non-invasive biomarkers for the diagnosis and prognosis of Bevacizumab-treated mCRC patients. We observed that baseline miRNA-21 and 92a outperformed carcinoembryonic antigen levels in the diagnosis of our 44 mCRC patients, compared to 17 healthy volunteers. In addition, patients who died presented higher levels of miRNA-92a and 222 at 24 weeks. However, in the multivariate Cox analysis, higher levels of miRNA-222 at 24 weeks were associated with lower overall survival. Altogether, these data indicate that EV-miRNAs have a strong potential as liquid biopsy biomarkers for the identification and prognosis of mCRC.

Bring along your friends: Homotypic and heterotypic circulating tumor cell clustering to accelerate metastasis

Metastasis formation is a hallmark of invasive cancers and it is achieved through the shedding of circulating tumor cells (CTCs) from the primary site into the blood circulation. There, CTCs are found as single cells or as multicellular clusters, with clusters carrying an elevated ability to survive within the bloodstream and initiate new metastatic lesions at distant sites. Clusters of CTCs include homotypic clusters made of cancer cells only, as well as heterotypic clusters that incorporate stromal or immune cells along with cancer cells. Both homotypic and heterotypic CTC clusters are characterized by a high metastasis-forming capability, high proliferation rate and by distinct molecular features compared to single CTCs, and their presence in the peripheral circulation of cancer patients is generally associated with a poor prognosis. In this short review, we summarize the current literature that describes homotypic and heterotypic CTC clusters, both in the context of their molecular characteristics as well as their value in the clinical setting. While CTC clusters have only recently emerged as key players in the metastatic process and many aspects of their biology remain to be investigated, a detailed understanding of their vulnerabilities may pave the way towards the generation of new metastasis-suppressing agents.

Genetic Analysis of Circulating Tumour Cells

The classification of human cancers has traditionally relied on the tissue of origin, the histologic appearance and anatomical extent of disease, otherwise referred to as grade and stage. However, this system fails to explain the highly variable clinical behaviour seen for any one cancer. Molecular characterization through techniques such as next-generation sequencing (NGS) has led to an appreciation of the extreme genetic heterogeneity that underlies most human cancers. Because of the difficulties associated with fresh tissue biopsy, interest has increased in using circulating tumour material, such as circulating tumour cells (CTCs), as a non-invasive way to access tumour tissue. CTC enumeration has been demonstrated to have prognostic value in metastatic breast, colon and prostate cancers. Recent studies have also shown that CTCs are suitable material for molecular characterization, using techniques such as reverse transcription-polymerase chain reaction (RT-PCR), fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and NGS. Furthermore, genetic analysis of CTCs may be more suitable to study tumour heterogeneity and clonal evolution than fresh tissue biopsy. Whether blood-based biopsy techniques will be accepted as a replacement to fresh tissue biopsies remains to be seen, but there is reason for optimism. While significant barriers to this acceptance exist, blood-based biopsy techniques appear to be reliable and representative alternatives to fresh tissue biopsy.

The prognostic role of circulating tumor cells in colorectal cancer

Introduction: Metastasis is the main cause of cancer-associated death in colorectal cancer (CRC). The presence of circulating tumor cells (CTC) in the blood is associated with an increased risk of recurrence and poor prognosis. The clinical significance of CTCs as a novel biomarker has been extensively studied in the last decade. It has been shown that CTC detection applies to early cancer detection. The presence of CTCs is associated with metastatic spread and poor survival and is also useful as a marker for therapy response.Areas covered: We summarize the role of CTC in CRC, their clinical significance, current methods for CTC detection and challenges as well as future perspectives of CTC research.Expert commentary: The clinical significance of CTC in CRC patients is well established. Although insightful, the available marker-based approaches hampered our understanding of the CTCs and their biology, as such approaches do not take into account the heterogeneity of these cell populations. New technologies should expand the marker-based detection to multi biomarker-based approaches together with recent technological advances in microfluidics for single cell enrichment and analysis.

Promising Colorectal Cancer Biomarkers for Precision Prevention and Therapy

Colorectal cancer (CRC) has been ranked as the third most prevalent cancer worldwide. Indeed, it represents 10.2% of all cancer cases. It is also the second most common cause of cancer mortality, and accounted for about 9.2% of all cancer deaths in 2018. Early detection together with a correct diagnosis and staging remains the most effective clinical strategy in terms of disease recovery. Thanks to advances in diagnostic techniques, and improvements of surgical adjuvant and palliative therapies, the mortality rate of CRC has decreased by more than 20% in the last decade. Cancer biomarkers for the early detection of CRC, its management, treatment and follow-up have contributed to the decrease in CRC mortality. Herein, we provide an overview of molecular biomarkers from tumor tissues and liquid biopsies that are approved for use in the CRC clinical setting for early detection, follow-up, and precision therapy, and of biomarkers that have not yet been officially validated and are, nowadays, under investigation.

Gut butyrate-producing organisms correlate to Placenta Specific 8 protein: Importance to colorectal cancer progression

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Genes from stools have molecular significance with CRC tumorgenesis.

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SCFAs, the metabolites of microbiota, can suppress CRC tumorigenesis.

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Relationship between colonic genes, gut microbiota, or their metabolites is significant.

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Changes of PLAC8 and butyrate-producing organisms were found in stools of CRC patients.

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Butyrate can reduce the CRC formation through regulating PLAC8 expression.

Tumor metastasis or recurrence often occurs in patients with curative resection of colorectal cancer (CRC). Placental-specific 8 (PLAC8), which has increased expression in stool, may be associated with CRC recurrence. Insights into the role of PLAC8 in CRC recurrence and its clinical significance may support to develop strategies for preventing CRC recurrence and deterioration. Clinical tissues, cell and animal models were used to clarify the roles of PLAC8 in CRC tumorigenesis, invasion, and migration. Next-generation sequencing of 16S ribosomal DNA has been used to assess the gut microbiota in stool of CRC patients. We found that PLAC8 was upregulated in tissues from patients with late-stage CRC. In our in vitro studies, PLAC8 was dynamically regulated in mitotic cells. Overexpressed PLAC8 was nucleated at the centrosome during mitosis, and therefore, PLAC8 overexpression might increase cell growth and migration (all p < 0.05). The tumorigenic and invasive effects of PLAC8 on CRC cells were also confirmed in a xenograft mouse model. We further identified reduced levels of two butyrate-producing organisms, Butyricicoccus and Prevotella spp., in stools from CRC patients. We found that butyrate downregulated PLAC8 expression and induced apoptosis in PLAC8-overexpressing cells. Our data suggests that PLAC8 gene and protein expression and dysbiosis of gut microflora, especially in butyrate-producing microorganisms, may be indicators of CRC progression.

A prospective feasibility study evaluating the role of multimodality imaging and liquid biopsy for response assessment in locally advanced rectal carcinoma

PURPOSE

Colorectal cancer is a commonly encountered disease that poses several diagnostic and therapeutic challenges. The inherent heterogeneity of tumor biology and propensity to relapse despite "curative" resection pose significant challenges with regard to response assessment. Although MR imaging already plays a key role in primary staging of patients with rectal carcinoma, its reliability in restaging after neoadjuvant therapy is debatable (Van der broek et al. in Dis Colon Rectum 60(3):274-283, 2017). Therefore, there is significant interest in developing additional methods which may improve diagnostic accuracy. This study aims to evaluate the role of multimodality imaging and liquid biopsy in therapeutic response assessment.

METHODS

Seventeen patients were enrolled into the study over a span of 24 months. All underwent hybrid PET-MRI and CT-perfusion (CT-P), prior to and following neoadjuvant therapy for locally advanced rectal carcinoma. Twelve of the 17 patients also underwent liquid biopsy, which consisted of blood sampling and analysis of circulating tumor cells (CTCs) and extracellular vesicles (EVs), including cell fragments and microparticles (MPs), using the Cell Search System (Menarini Silicon Biosystems). SUV, DWI, and ADC were calculated during PET-MRI, and several parameters were evaluated during CT-perfusion, including average perfusion, blood flow (BF), blood volume (BV), mean transit time (MTT), permeability-surface area product (PS), contrast extraction efficiency (E), and K-trans (K). Changes observed pre- and post-neoadjuvant therapy in each modality were compared to tumor response at histopathology using a modified Ryan tumor regression grading system.

RESULTS

Of the 17 patients included in the study, 14 were classified as non-responders, and 3 were classified as responders as determined by the modified Ryan Tumor Regression Grade (TRG) scoring system (Van der broek et al. in Dis Colon Rectum 60(3):274-283, 2017). When combined, blood markers and CT-P parameters (mean transit time (MTT), K-trans, and permeability-surface area product (PS)) produced the strongest models (p < 0.01). PET (SUV measurement) combined with CT-P-derived K-trans produced a marginally significant (p = 0.057) model for predicting response. MRI-derived ADC value did not provide a significant model for response prediction.

CONCLUSION

A model of CT-P parameters plus liquid biopsy more accurately predicts tumor response than PET-MRI, CT-P alone, or liquid biopsy alone. These results suggest that in the evaluation of treatment response, liquid biopsy could provide additional information to functional imaging modalities such as CT-P and should therefore be explored further in a trial with larger sample size.

Current progress in the clinical use of circulating tumor cells as prognostic biomarkers

The process of metastasis is characterized by the shedding of tumor cells into the bloodstream, where they are transported to other parts of the body to seed new tumors. These cells, known as circulating tumor cells (CTCs), have the potential to reveal much about an individual cancer case, and theoretically can aid in the prediction of outcomes and design of precision treatments. Recent advances in technology now allow for the robust and reproducible characterization of CTCs from a simple blood draw. Both the number of circulating cells and important molecular characteristics correlated with clinical phenotypes such as drug resistance can be obtained and used for real-time prognostic analysis. Molecular characterization can provide a snapshot of the activity of the main tumor (serving as a "liquid biopsy") and early warnings concerning changes such as the development of resistance, and aid in predicting the efficacy of different therapeutic approaches for treatment optimization. Herein, the authors review the current clinical use of CTCs as prognostic biomarkers for several different cancers. The quantification of CTCs can lead to more accurate staging and decision making regarding options such as adjuvant chemotherapy.

Circulating biomarkers for early detection and clinical management of colorectal cancer

New non-invasive approaches that can complement and improve on current strategies for colorectal cancer (CRC) screening and management are urgently needed. A growing number of publications have documented that components of tumors, which are shed into the circulation, can be detected in the form of liquid biopsies and can be used to detect CRC at early stages, to predict response to certain therapies and to detect CRC recurrence in a minimally invasive way. The analysis of circulating tumor DNA (ctDNA), tumor-derived cells (CTC, circulating tumor cells) or circulating microRNA (miRNA) in blood and other body fluids, have a great potential to improve different aspects of CRC management. The challenge now is to find which types of components, biofluids and detection methods would be the most suitable to be applied in the different steps of CRC detection and treatment. This chapter will provide an up to date review on ctDNA, CTCs and circulating miRNAs as new biomarkers for CRC, either for clinical management or early detection, highlighting their advantages and limitations.

Heterogeneity in Circulating Tumor Cells: The Relevance of the Stem-Cell Subset

The release of circulating tumor cells (CTCs) into vasculature is an early event in the metastatic process. The analysis of CTCs in patients has recently received widespread attention because of its clinical implications, particularly for precision medicine. Accumulated evidence documents a large heterogeneity in CTCs across patients. Currently, the most accepted view is that tumor cells with an intermediate phenotype between epithelial and mesenchymal have the highest plasticity. Indeed, the existence of a meta-stable or partial epithelial–mesenchymal transition (EMT) cell state, with both epithelial and mesenchymal features, can be easily reconciled with the concept of a highly plastic stem-like state. A close connection between EMT and cancer stem cells (CSC) traits, with enhanced metastatic competence and drug resistance, has also been described. Accordingly, a subset of CTCs consisting of CSC, present a stemness profile, are able to survive chemotherapy, and generate metastases after xenotransplantation in immunodeficient mice. In the present review, we discuss the current evidence connecting CTCs, EMT, and stemness. An improved understanding of the CTC/EMT/CSC connections may uncover novel therapeutic targets, irrespective of the tumor type, since most cancers seem to harbor a pool of CSCs, and disclose important mechanisms underlying tumorigenicity.

Consensus and controversies regarding follow-up after treatment with curative intent of nonmetastatic colorectal cancer: a synopsis of guidelines used in countries represented in the European Society of Coloproctology

AIM

It is common clinical practice to follow patients for a period of years after treatment with curative intent of nonmetastatic colorectal cancer, but follow-up strategies vary widely. The aim of this systematic review was to provide an overview of recommendations on this topic in guidelines from member countries of the European Society of Coloproctology, with supporting evidence.

METHOD

A systematic search of Medline, Embase and the guideline databases Trip database, BMJ Best Practice and Guidelines International Network was performed. Quality assessment included use of the AGREE-II tool. All topics with recommendations from included guidelines were identified and categorized. For each subtopic, a conclusion was made followed by the degree of consensus and the highest level of evidence.

RESULTS

Twenty-one guidelines were included. The majority recommended that structured follow-up should be offered, except for patients in whom treatment of recurrence would be inappropriate. It was generally agreed that clinical visits, measurement of carcinoembryoinc antigen and liver imaging should be part of follow-up, based on a high level of evidence, although the frequency is controversial. There was also consensus on imaging of the chest and pelvis in rectal cancer, as well as endoscopy, based on lower levels of evidence and with a level of intensity that was contradictory.

CONCLUSION

In available guidelines, multimodal follow-up after treatment with curative intent of colorectal cancer is widely recommended, but the exact content and intensity are highly controversial. International agreement on the optimal follow-up schedule is unlikely to be achieved on current evidence, and further research should refocus on individualized 'patient-driven' follow-up and new biomarkers.

Circulating tumor cells as an independent prognostic factor in advanced colorectal cancer: a retrospective study in 121 patients

PURPOSE

This study aimed to evaluate the prognostic value of circulating tumor cells (CTCs) in advanced colorectal cancer (CRC) patients during chemotherapy course.

METHODS

From January 2016 to September 2017, the clinicopathological variables, such as gender, age, tumor location, tumor de-differentiation, depth of invasion, lymphatic invasion, distant metastasis, TNM stage, CTCs enumeration during 2-6 cycles of chemotherapy, and serum carcinoembryonic antigen (CEA) level during the same period, of 121 newly acquired and histopathologically confirmed CRC patients were collected from the Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. All patients were followed up for survival until the end of November 2018. Statistical analysis focused on the associations between CTCs counts and clinicopathological variables. Overall survival (OS) and progression-free survival (PFS) among different prognostic factors were calculated using the Kaplan-Meier method, and the differences between the survival curves were compared by using the log-rank test. Factors of prognostic significance were investigated with the multivariate Cox regression analysis.

RESULTS

Here, 71 of 121 patients were CTC-positive, in which CTC-positive rate was positively correlated with the depth of invasion, lymphatic invasion, distant metastasis, TNM stage, and serum CEA level (P < 0.05 for all). However, no significant difference was found between CTC-positive and other clinicopathological variables (P > 0.05 for all), such as gender, age, tumor location, and tumor de-differentiation. CTCs counts gradually increased with the advancement of depth of invasion (P = 0.002), lymphatic invasion (P = 0.004), distant metastasis (P = 0.007), TNM stage (P = 0.001), serum CEA level (P = 0.001), and decreased tumor de-differentiation (P = 0.011). Furthermore, the Kaplan-Meier survival curves showed that patients with CTC-positive had a significantly unfavorable PFS (14 vs. 23 months, P = 0.001) and OS (18 vs. 25 months, P = 0.003). The multivariate Cox regression analyses revealed that the presence of CTCs during chemotherapy was an independent factor for unfavorable PFS (hazard ratio (HR) 2.682, P = 0.017, 95% confidence interval (CI) 1.193-6.029) and OS (HR 2.790, P = 0.048, 95% CI 1.010-7.705) in advanced CRC patients.

CONCLUSIONS

This study provided an evidence that the presence of CTCs may be valuable for predicting survival outcome, and CTCs was associated with unfavorable survival in advanced CRC patients during chemotherapy.

Clinical relevance of circulating molecules in cancer: focus on gastrointestinal stromal tumors

In recent years, growing research interest has focused on the so-called liquid biopsy. A simple blood test offers access to a plethora of information, which might be extremely helpful in understanding or characterizing specific diseases. Blood contains different molecules, of which circulating free DNA (cfDNA), circulating tumor DNA (ctDNA), circulating tumor cells (CTCs) and extracellular vesicles (EVs) are the most relevant. Conceivably, these molecules have the potential for tumor diagnosis, monitoring tumor evolution, and evaluating treatment response and pharmacological resistance. This review aims to present a state-of-the-art of recent advances in circulating DNA and circulating RNA in gastrointestinal stromal tumors (GISTs). To date, progress in liquid biopsy has been scarce in GISTs due to several issues correlated with the nature of the pathology. Namely, heterogeneity in primary and secondary mutations in key driver genes has greatly slowed the development and application in GISTs, unlike in other tumor types in which liquid biopsy has already been translated into clinical practice. However, meaningful novel data have shown in recent years a significant clinical potential of ctDNA, CTCs, EVs and circulating RNA in GISTs.

Detection of circulating tumor cells in drainage venous blood from colorectal cancer patients using a new filtration and cytology-based automated platform

Numerous technologies exist to detect circulating tumor cells (CTCs), although reports on cytological detection of CTCs remain limited. We recently developed a cytology-based CTC detection device using glass slides and light microscopy. In this study, we automated this previously manual device to improve its efficiency and cost effectiveness for clinical applications. We conducted a pilot study using this device to compare CTCs in peripheral blood (PB) and draining venous blood (DVB) from patients with colorectal cancer (CRC). The cytology-based automated CTC detection platform consisted of a disposable filtration device with a three-dimensional (3D) metal filter and multichannel automated CTC enrichment device. This platform allowed rapid and gentle filtration of CTCs and their efficient transfer from the filter to glass slides for subsequent Papanicolaou (Pap) and immunocytochemical (ICC) staining. Cytological diagnosis of CTCs was performed by observing permanent glass slide specimens by light microscopy. The current pilot clinical study enrolled CRC patients (n = 26) with stage I–IV tumors, who underwent surgery. PB was collected before surgery, and DVB was obtained from the mesenteric vein immediately after resection. Based on the CTC morphology obtained from PB and DVB samples, we proposed the following cytological criteria for the diagnosis of CTCs: pan-cytokeratin-positive, atypical cells with malignant morphological features identified by Pap staining. The numbers of CTCs defined by these criteria were significantly higher in DVB than PB from CRC patients (p<0.01), and the number of CTCs in DVB was increased significantly with stage progression (p<0.05). These results suggest that DVB may be another potential source of CTCs other than PB for liquid biopsies including downstream analysis. This automated cytology-based CTC detection device therefore provides a unique and powerful tool to investigate the significance of CTCs in CRC patients in a clinical setting.