Tumor-selective replication herpes simplex virus-based technology significantly improves clinical detection and prognostication of viable circulating tumor cells

HSV: The scout and assault for digestive system tumors

More than 25% of all malignant tumors are digestive system tumors (DSTs), which mostly include esophageal cancer, gastric cancer, pancreatic cancer, liver cancer, gallbladder cancer and cholangiocarcinoma, and colorectal cancer. DSTs have emerged as one of the prominent reasons of morbidity and death in many nations and areas around the world, posing a serious threat to human life and health. General treatments such as radiotherapy, chemotherapy, and surgical resection can poorly cure the patients and have a bad prognosis. A type of immunotherapy known as oncolytic virus therapy, have recently shown extraordinary anti-tumor effectiveness. One of the viruses that has been the subject of the greatest research in this field, the herpes simplex virus (HSV), has shown excellent potential in DSTs. With a discussion of HSV-1 based on recent studies, we outline the therapeutic effects of HSV on a number of DSTs in this review. Additionally, the critical function of HSV in the detection of cancers is discussed, and some HSV future possibilities are shown.

Advances in the Biology, Detection Techniques, and Clinical Applications of Circulating Tumor Cells

Circulating tumor cells (CTCs) play a crucial role in tumor recurrence and metastasis, and their early detection has shown remarkable benefits in clinical theranostics. However, CTCs are extremely rare, thus detecting them in the blood is very challenging. New CTC detection techniques are continuously being developed, enabling deeper analysis of CTC biology and potential clinical application. This article reviews current CTC detection techniques and their clinical application. CTCs have provided, and will continue to provide, important insights into the process of metastasis, which could lead to development of new therapies for different cancers.

Circulating tumor DNA for diagnosis, prognosis and treatment of gastrointestinal malignancies

Minimally invasive detection of circulating tumor DNA (ctDNA) in peripheral blood or other body fluids of patients with gastrointestinal malignancies via liquid biopsy has emerged as a promising biomarker. This is urgently needed, as conventional imaging and plasma protein-derived biomarkers lack sensitivity and specificity in prognosis, early detection of relapse or treatment monitoring. This review summarizes the potential role of liquid biopsy in diagnosis, prognosis and treatment monitoring of gastrointestinal malignancies, including upper gastrointestinal, liver, bile duct, pancreatic and colorectal cancer. CtDNA can now be part of the clinical routine as a promising, highly sensitive and specific biomarker with a broad range of applicability. Liquid-biopsy based postoperative relapse prediction could lead to improved survival by intensification of adjuvant treatment in patients identified to be at risk of early recurrence. Moreover, ctDNA allows monitoring of antineoplastic treatment success, with identification of potentially developed resistance or therapeutic targets during the course of treatment. It may also assist in early change of chemotherapy in metastatic gastrointestinal malignancies prior to imaging findings of relapse. Nevertheless, clinical utility is dependent on the tumor’s entity and burden.

Tumor‐targeted fluorescence labeling systems for cancer diagnosis and treatment

Conventional imaging techniques are available for clinical identification of tumor sites. However, detecting metastatic tumor cells that are spreading from primary tumor sites using conventional imaging techniques remains difficult. In contrast, fluorescence‐based labeling systems are useful tools for detecting tumor cells at the single‐cell level in cancer research. The ability to detect fluorescent‐labeled tumor cells enables investigations of the biodistribution of tumor cells for the diagnosis and treatment of cancer. For example, the presence of fluorescent tumor cells in the peripheral blood of cancer patients is a predictive biomarker for early diagnosis of distant metastasis. The elimination of fluorescent tumor cells without damaging normal tissues is ideal for minimally invasive treatment of cancer. To capture fluorescent tumor cells within normal tissues, however, tumor‐specific activated target molecules are needed. This review focuses on recent advances in tumor‐targeted fluorescence labeling systems, in which indirect reporter labeling using tumor‐specific promoters is applied to fluorescence labeling of tumor cells for the diagnosis and treatment of cancer. Telomerase promoter‐dependent fluorescence labeling using replication‐competent viral vectors produces fluorescent proteins that can be used to detect and eliminate telomerase‐positive tumor cells. Tissue‐specific promoter‐dependent fluorescence labeling enables identification of specific tumor cells. Vimentin promoter‐dependent fluorescence labeling is a useful tool for identifying tumor cells that undergo epithelial–mesenchymal transition (EMT). The evaluation of tumor cells undergoing EMT is important for accurately assessing metastatic potential. Thus, tumor‐targeted fluorescence labeling systems represent novel platforms that enable the capture of tumor cells for the diagnosis and treatment of cancer.

Isolation and Genomic Analysis of Single Circulating Tumor Cell Using Human Telomerase Reverse Transcriptase and Desmoglein-2

As epithelial cells in the circulation are considered to originate from the tumor, the epithelial cell adhesion molecule has been commonly used as a standard marker for circulating tumor cells (CTCs) isolation. However, it seems to disappear after the epithelial-mesenchymal transition that most cancer cells undergo for intravasation. Thus, more advanced techniques for CTC detection are needed to better understand the clinical significance of CTCs. A cancer cell-specifically-infecting or replicating virus that codes a fluorescent monitor gene can be a solution to efficiently detect CTCs. Thus, the authors designed an adenovirus to bind to desmoglein-2, which is highly expressed in most cancer cells. A cancer-specific human telomerase reverse transcriptase promoter is inserted to control a viral E1 region. The adenovirus is utilized to compare the number of CTCs from renal cell carcinoma and prostate cancer patients before and after surgery. The isolated two or three CTCs are eligible for whole genome sequencing. The genomic analysis proves the difference of variants between primary tumors and CTCs. Taken together, it is a fast and exact serial method for CTC isolation and the enriched genome sequencing may be used to determine the prognosis and as a point-of-care system for patients with cancer.

Improving the diagnosis of prostate cancer by telomerase-positive circulating tumor cells: A prospective pilot study

BACKGROUND

Prostate-specific antigen (PSA) testing is limited in identifying prostate cancer (PCa) with modestly elevated PSA levels. Therefore, a robust method for the diagnosis of PCa is urgently needed.

METHODS

A total of 203 men with a PSA level of ≥4 ng/ml were eligible for enrollment in this study from July 2018 to May 2021, and randomly divided into a training set (n=78) and a validation set (n=125). Circulating tumor cells (CTCs) were detected using telomerase-based CTC detection (TBCD), and the diagnostic ability was evaluated using receiver operating characteristic (ROC) and logistic regression analyses.

FINDINGS

In the training set, the area under the curve (AUC) of CTCs was 0.842 with a sensitivity of 80.33% and specificity of 82.35%. In the validation set, the AUC of CTCs was 0.789, with a sensitivity of 79.31% and specificity of 81.58%. There was no significant difference between CTCs (AUC=0.793) and PSA (AUC=0.697) in the range of 4-50 ng/ml. In the ranges of 4-20 ng/ml and 4-10 ng/ml, the AUC of CTCs were 0.811 and 0.825, respectively, which were superior to the AUC of PSA (0.588 and 0.541). The sensitivity and specificity of CTCs in the three PSA groups were higher than 80%. Moreover, we further established a CTC+PSA combined model, which could significantly improve the diagnostic ability of a PSA level of '4-10 ng/ml'.

INTERPRETATION

TBCD could be a valuable method for distinguishing PCa and benign prostatic disease, especially in the PSA diagnostic gray area of '4-10 ng/ml'.

A chimeric virus-based probe unambiguously detects live circulating tumor cells with high specificity and sensitivity

The current methods for detecting circulating tumor cells (CTCs) suffer from several drawbacks. We report a novel method that is based on a chimeric virus probe and can detect CTCs with extremely high specificity and sensitivity. Moreover, it exclusively detects live CTCs, and its detection efficacy is not impacted by the variation of epithelial cell adhesion molecule (EpCAM) expression. The chimeric virus probe is composed of a capsid from human papillomavirus that provides the detection with high specificity and an SV40-based genome that can amplify extensively inside CTCs and, hence, endows the detection with high sensitivity. Furthermore, different marker genes can be incorporated into the probe to provide detection with versatility. These unique capabilities will likely improve the validity and utility of this CTC detection in several clinical applications, which is one of the drawbacks suffered by many of the current CTC detection methods.

Telomerase-positive circulating tumor cells are associated with poor prognosis via a neutrophil-mediated inflammatory immune environment in glioma

BACKGROUND

Gliomas are the most common aggressive cancer in the central nervous system. Considering the difficulty in monitoring glioma response and progression, an approach is needed to evaluate the progression or survival of patients with glioma. We propose an application to facilitate clinical detection and treatment monitoring in glioma patients by using telomerase-positive circulating tumor cells (CTCs) and to further evaluate the relationship between the immune microenvironment and CTCs in glioma patients.

METHODS

From October 2014 to June 2017, 106 patients newly diagnosed with glioma were enrolled. We used the telomerase reverse transcriptase CTC detection method to detect and analyze the CTC statuses of glioma patients before and after surgery. FlowSight and FISH confirmed the CTCs detected by the telomerase-based method. To verify the correlation between CTCs and the immune response, peripheral white blood cell RNA sequencing was performed.

RESULTS

CTCs were common in the peripheral blood of glioma patients and were not correlated with the pathological classification or grade of patients. The results showed that the presence of postoperative CTCs but not preoperative CTCs in glioma patients was a poor prognostic factor. The level of postoperative CTCs, which predicts a poor prognosis after surgery, may be associated with neutrophils. RNA sequencing suggested that postoperative CTCs were positively correlated with innate immune responses, especially the activation of neutrophils and the generation of neutrophil extracellular traps, but negatively correlated with the cytotoxic response.

CONCLUSIONS

Our results showed that telomerase-positive CTCs can predict a poor prognosis of patients with glioma. Our results also showed a correlation between CTCs and the immune macroenvironment, which provides a new perspective for the treatment of glioma.

Research progress on circulating tumor cells of hepatocellular carcinoma

Circulating tumor cells (CTCs) are the cells released from the primary tumor and found in the peripheral blood, which can colonize and develop at a distance through blood circulation. At present, the commonly used separation and detection methods of CTCs are mainly divided into physical methods, biological methods, and microfluidic chip-based methods. Monitoring CTC count and cell phenotype is of great significance for early screening and diagnosis of hepatocellular carcinoma (HCC). Moreover, the CTC count and cell phenotype are related to assessing the clinical efficacy of the treatment of HCC and the clinical stage of HCC patients. The CTCs count is also closely related to the overall survival, progression-free survival, and postoperative recurrence of patients with HCC.

Combination of CT and telomerase+ circulating tumor cells improves diagnosis of small pulmonary nodules

BACKGROUND

Early diagnosis and treatment are key to the long-term survival of lung cancer patients. Although CT has significantly contributed to the early diagnosis of lung cancer, there are still consequences of excessive or delayed treatment. By improving the sensitivity and specificity of circulating tumor cell (CTC) detection, a solution was proposed for differentiating benign from malignant pulmonary nodules.

METHODS

In this study, we used telomerase reverse transcriptase–based (TERT-based) CTC detection (TBCD) to distinguish benign from malignant pulmonary nodules < 2 cm and compared this method with the pathological diagnosis as the gold standard. FlowSight and FISH were used to confirm the CTCs detected by TBCD.

RESULTS

Our results suggest that CTCs based on TBCD can be used as independent biomarkers to distinguish benign from malignant nodules and are significantly superior to serum tumor markers. When the detection threshold was 1, the detection sensitivity and specificity of CTC diagnosis were 0.854 and 0.839, respectively. For pulmonary nodules ≤ 1 cm and 1–2 cm, the sensitivity and specificity of CTCs were both higher than 77%. Additionally, the diagnostic ability of CTC-assisted CT was compared by CT detection. The results show that CT combined with CTCs could significantly improve the differentiation ability of benign and malignant nodules in lung nodules < 2 cm and that the sensitivity and specificity could reach 0.899 and 0.839, respectively.

CONCLUSION

TBCD can effectively diagnose pulmonary nodules and be used as an effective auxiliary diagnostic scheme for CT diagnosis.

FUNDING

National Key Research and Development Project grant nos. 2019YFC1315700 and 2017YFC1308702, CAMS Initiative for Innovative Medicine grant no. 2017-I2M-1-005, and National Natural Science Foundation of China grant no. 81472013.

Blood-Based Biomarkers for Glioma in the Context of Gliomagenesis: A Systematic Review

BACKGROUND

Gliomas are the most common and aggressive tumors of the central nervous system. A robust and widely used blood-based biomarker for glioma has not yet been identified. In recent years, a plethora of new research on blood-based biomarkers for glial tumors has been published. In this review, we question which molecules, including proteins, nucleic acids, circulating cells, and metabolomics, are most promising blood-based biomarkers for glioma diagnosis, prognosis, monitoring and other purposes, and align them to the seminal processes of cancer.

METHODS

The Pubmed and Embase databases were systematically searched. Biomarkers were categorized in the identified biomolecules and biosources. Biomarker characteristics were assessed using the area under the curve (AUC), accuracy, sensitivity and/or specificity values and the degree of statistical significance among the assessed clinical groups was reported.

RESULTS

7,919 references were identified: 3,596 in PubMed and 4,323 in Embase. Following screening of titles, abstracts and availability of full-text, 262 articles were included in the final systematic review. Panels of multiple biomarkers together consistently reached AUCs >0.8 and accuracies >80% for various purposes but especially for diagnostics. The accuracy of single biomarkers, consisting of only one measurement, was far more variable, but single microRNAs and proteins are generally more promising as compared to other biomarker types.

CONCLUSION

Panels of microRNAs and proteins are most promising biomarkers, while single biomarkers such as GFAP, IL-10 and individual miRNAs also hold promise. It is possible that panels are more accurate once these are involved in different, complementary cancer-related molecular pathways, because not all pathways may be dysregulated in cancer patients. As biomarkers seem to be increasingly dysregulated in patients with short survival, higher tumor grades and more pathological tumor types, it can be hypothesized that more pathways are dysregulated as the degree of malignancy of the glial tumor increases. Despite, none of the biomarkers found in the literature search seem to be currently ready for clinical implementation, and most of the studies report only preliminary application of the identified biomarkers. Hence, large-scale validation of currently identified and potential novel biomarkers to show clinical utility is warranted.

Circulating Tumor Cells for Glioma

Liquid biopsy has entered clinical applications for several cancers, including metastatic breast, prostate, and colorectal cancer for CTC enumeration and NSCLC for EGFR mutations in ctDNA, and has improved the individualized treatment of many cancers, but relatively little progress has been made in validating circulating biomarkers for brain malignancies. So far, data on circulating tumor cells about glioma are limited, the application of circulating tumor cells as biomarker for glioma patients has only just begun. This article reviews the research status and application prospects of circulating tumor cells in gliomas. Several detection methods and research results of circulating tumor cells about clinical research in gliomas are briefly discussed. The wide application prospect of circulating tumor cells in glioma deserves further exploration, and the research on more sensitive and convenient detection methods is necessary.

Prospective Exploratory Study of the Clinical Significance of Circulating Tumor Cells in Patients With Small Cell Lung Cancer Exposed to Prophylactic Cranial Irradiation

OBJECTIVE

Circulating tumor cells (CTCs) can predict the efficacy of anti-cancer treatments and indicate prognosis. Here we investigate the significance of CTCs in relation to the prediction of treatment efficacy and prognosis in patients with small cell lung cancer (SCLC) who have received prophylactic cranial irradiation (PCI).

METHODS

CTCs were detected in 20 patients with SCLC before and after PCI using the oHSV1-hTERT-GFP method. The primary endpoints were progression-free survival (PFS) and overall survival (OS).

RESULTS

Eleven patients had limited-stage SCLC, and nine had extensive-stage SCLC. All patients completed chemo-radiotherapy and received PCI. The median baseline CTC count before PCI was 12. After PCI, the median CTC count was 4. The median follow-up time for all enrolled patients was 39.2 months. The median PFS and OS were significantly reduced in patients with ≥4 CTCs after PCI compared to those with <4 CTCs (PFS, 28.1 months vs. not reached, p = 0.001; OS, not reached vs. not reached, p = 0.029). Seven of the 10 patients with ≥4 CTCs after PCI failed after treatment, whereas the10 patients with <4 CTCs after PCI remained alive without tumors. The median PFS and OS were significantly improved in patients who exhibited a rate of CTC decline of ≥58% after PCI compared with patients who exhibited a decline rate of <58% (PFS, 26.4 months vs. not reached, p = 0.006; OS, not reached vs. not reached, p = 0.029).

CONCLUSION

In SCLC patients who receive PCI, the CTC count and rate of CTC decline after PCI significantly correlate with prognosis.

Circulating tumour cells in pancreatic cancer: A systematic review and meta-analysis of clinicopathological implications

BACKGROUND

The detection and quantification of circulating tumour cells (CTCs) in pancreatic cancer (PC) has the potential to provide prognostic information. The aim of this review was to provide an overview of the literature surrounding CTCs in PC.

METHODS

A systematic literature review on CTCs in PC between 2005-2020 was performed. Data based on peripheral vein samples were used to determine the positivity rate of CTCs, their prognostic significance and their relative numbers compared to portal vein (PV) samples.

RESULTS

The overall CTC detection rate in forty-four articles was 65% (95%CI: 55-75%). Detection rate for CellSearch was 26% (95%CI: 14-38%), which was lower than for both filtration and microfluidic techniques. In nine studies with >50 patients, overall survival was worse with CTC positivity (HR 1.82; 95%CI: 1.61-2.05). Five of seven studies which described PV CTC collection provided patient-level data. PV CTC yield was 7.7-fold (95%CI 1.35-43.9) that of peripheral blood.

CONCLUSIONS

CTCs were detected in the peripheral circulation of most patients with PC and may be related to prognosis and disease stage. PV blood contains more CTCs than peripheral blood sampling. This review points to the maturation of techniques of CTC enrichment, and its evidence base for eventual clinical deployment.

A Novel Liquid Biopsy Strategy to Detect Small Amounts of Cancer Cells Using Cancer-Specific Replication Adenoviruses

Circulating tumor cells (CTCs) are a promising source of clinical and biological cancer information and can be a material for liquid biopsy. However, detecting and capturing these cells remains a challenge. Various biological factors (e.g., cell surface proteins, cell size, deformability, or dielectrophoresis) have been applied to detect CTCs. Cancer cells dramatically change their characteristics during tumorigenesis and metastasis. Hence, defining a cell as malignant using such a parameter is difficult. Moreover, immortality is an essential characteristic of cancer cells. Telomerase elongates telomeres and plays a critical role in cellular immortality and is specifically activated in cancer cells. Thus, the activation of telomerase can be a good fingerprint for cancer cells. Telomerase cannot be recognized by antibodies in living cells because it is a nuclear enzyme. Therefore, telomerase-specific replication adenovirus, which expresses the green fluorescent protein, has been applied to detect CTCs. This review explores the overview of this novel technology and its application in gynecological cancers.

The CXCL12-CXCR4 Signaling Axis Plays a Key Role in Cancer Metastasis and is a Potential Target for Developing Novel Therapeutics against Metastatic Cancer

Metastasis is the main cause of death in cancer patients; there is currently no effective treatment for cancer metastasis. This is primarily due to our insufficient understanding of the metastatic mechanisms in cancer. An increasing number of studies have shown that the C-X-C motif chemokine Ligand 12 (CXCL12) is overexpressed in various tissues and organs. It is a key niche factor that nurtures the pre-metastatic niches (tumorigenic soil) and recruits tumor cells (oncogenic "seeds") to these niches, thereby fostering cancer cell aggression and metastatic capabilities. However, the C-X-C motif chemokine Receptor 4 (CXCR4) is aberrantly overexpressed in various cancer stem/progenitor cells and functions as a CXCL12 receptor. CXCL12 activates CXCR4 as well as multiple downstream multiple tumorigenic signaling pathways, promoting the expression of various oncogenes. Activation of the CXCL12-CXCR4 signaling axis promotes Epithelial-Mesenchymal Transition (EMT) and mobilization of cancer stem/progenitor cells to pre-metastatic niches. It also nurtures cancer cells with high motility, invasion, and dissemination phenotypes, thereby escalating multiple proximal or distal cancer metastasis; this results in poor patient prognosis. Based on this evidence, recent studies have explored either CXCL12- or CXCR4-targeted anti-cancer therapeutics and have achieved promising results in the preclinical trials. Further exploration of this new strategy and its potent therapeutics effect against metastatic cancer through the targeting of the CXCL12- CXCR4 signaling axis may lead to a novel therapy that can clean up the tumor microenvironment ("soil") and kill the cancer cells, particularly the cancer stem/progenitor cells ("seeds"), in cancer patients. Ultimately, this approach has the potential to effectively treat metastatic cancer.

Dendritic cell biology and its role in tumor immunotherapy

As crucial antigen presenting cells, dendritic cells (DCs) play a vital role in tumor immunotherapy. Taking into account the many recent advances in DC biology, we discuss how DCs (1) recognize pathogenic antigens with pattern recognition receptors through specific phagocytosis and through non-specific micropinocytosis, (2) process antigens into small peptides with proper sizes and sequences, and (3) present MHC-peptides to CD4⁺ and CD8⁺ T cells to initiate immune responses against invading microbes and aberrant host cells. During anti-tumor immune responses, DC-derived exosomes were discovered to participate in antigen presentation. T cell microvillar dynamics and TCR conformational changes were demonstrated upon DC antigen presentation. Caspase-11-driven hyperactive DCs were recently reported to convert effectors into memory T cells. DCs were also reported to crosstalk with NK cells. Additionally, DCs are the most important sentinel cells for immune surveillance in the tumor microenvironment. Alongside DC biology, we review the latest developments for DC-based tumor immunotherapy in preclinical studies and clinical trials. Personalized DC vaccine-induced T cell immunity, which targets tumor-specific antigens, has been demonstrated to be a promising form of tumor immunotherapy in patients with melanoma. Importantly, allogeneic-IgG-loaded and HLA-restricted neoantigen DC vaccines were discovered to have robust anti-tumor effects in mice. Our comprehensive review of DC biology and its role in tumor immunotherapy aids in the understanding of DCs as the mentors of T cells and as novel tumor immunotherapy cells with immense potential.

Dendritic cell biology and its role in tumor immunotherapy

As crucial antigen presenting cells, dendritic cells (DCs) play a vital role in tumor immunotherapy. Taking into account the many recent advances in DC biology, we discuss how DCs (1) recognize pathogenic antigens with pattern recognition receptors through specific phagocytosis and through non-specific micropinocytosis, (2) process antigens into small peptides with proper sizes and sequences, and (3) present MHC-peptides to CD4⁺ and CD8⁺ T cells to initiate immune responses against invading microbes and aberrant host cells. During anti-tumor immune responses, DC-derived exosomes were discovered to participate in antigen presentation. T cell microvillar dynamics and TCR conformational changes were demonstrated upon DC antigen presentation. Caspase-11-driven hyperactive DCs were recently reported to convert effectors into memory T cells. DCs were also reported to crosstalk with NK cells. Additionally, DCs are the most important sentinel cells for immune surveillance in the tumor microenvironment. Alongside DC biology, we review the latest developments for DC-based tumor immunotherapy in preclinical studies and clinical trials. Personalized DC vaccine-induced T cell immunity, which targets tumor-specific antigens, has been demonstrated to be a promising form of tumor immunotherapy in patients with melanoma. Importantly, allogeneic-IgG-loaded and HLA-restricted neoantigen DC vaccines were discovered to have robust anti-tumor effects in mice. Our comprehensive review of DC biology and its role in tumor immunotherapy aids in the understanding of DCs as the mentors of T cells and as novel tumor immunotherapy cells with immense potential.

Telomerase-specific attenuated viruses, a definitive strategy or just one more in circulating tumor cells detection anthology?

The quantification and isolation of Circulating Tumor Cells (CTC) is being the battleground during last years. There are many groups that are investing economic resources in trying to solve this jigsaw. Technological platforms based on different proofs of concept have been developed achieving in some cases excellent results despite not having been able to detect the total compute of the patient's CTC population. The handicap of this matter has been the lack of universal markers. Several years have gone so that in detection of CTC is take into account a basic characteristic that possesses the most of tumor cells, the loss of inactivation of the enzyme telomerase. Gene therapy has been combined with telomerase activity concept for develop a molecular tool that makes it possible to identify CTC: Telomerase-specific replication-selective viruses. This review includes for the first time all the scientific studies that have been published to date with this advanced technology. Furthermore, it describes the role in the diagnosis and prognosis that Telomerase-specific attenuated viruses have been playing in cancer patients study during this last decade.

Liquid biopsy in pancreatic ductal adenocarcinoma: current status of circulating tumor cells and circulating tumor DNA

Reliable biomarkers are required to evaluate and manage pancreatic ductal adenocarcinoma. Circulating tumor cells and circulating tumor DNA are shed into blood and can be relatively easily obtained from minimally invasive liquid biopsies for serial assays and characterization, thereby providing a unique potential for early diagnosis, forecasting disease prognosis, and monitoring of therapeutic response. In this review, we provide an overview of current technologies used to detect circulating tumor cells and circulating tumor DNA and describe recent advances regarding the multiple clinical applications of liquid biopsy in pancreatic ductal adenocarcinoma.

Cooperation Between the Inflammation and Coagulation Systems Promotes the Survival of Circulating Tumor Cells in Renal Cell Carcinoma Patients

Most renal cell carcinoma (RCC) patients die from metastasis or recurrence after the spread of cancer to another organ, but the mechanisms underlying the intravascular survival of circulating tumor cells (CTCs) have not been completely deciphered. Additionally, although elevated plasma C-reactive protein (CRP) levels and thrombocytosis are strongly correlated and both indicate a poor prognosis for RCC patients, the bridge connecting inflammation and coagulation remains poorly understood. To explore the complicated relationship among inflammation, the coagulation system and CTC survival, we obtained viable CTC counts and clinical information from 106 treatment-naïve patients. In addition, we performed RNA sequencing on peripheral blood leukocytes from 21 of these patients. Patients with elevated CRP and fibrinogen (FIB) levels had higher CTC counts than patients with normal levels of these indexes. Each pair of the three variables (CTC count, CRP level and FIB level) was positively correlated. According to transcriptomic analysis of blood leukocytes, the functions of the 257 genes identified as being positively correlated with the CTC count indicated neutrophil extracellular trap (NET) formation. Indeed, gene set enrichment analysis (GSEA) suggested that NET formation or increased levels of NET markers would promote CTC viability. Additionally, the calculated NET score was positively correlated with the plasma FIB concentration, and both of these values were increased in patients with elevated CRP levels. Moreover, immunofluorescence staining showed that NETs were entangled with viable renal cancer cells and that the NET frameworks were decorated with NET-derived tissue factor (TF). Finally, analysis of 533 RCC samples from The Cancer Genome Atlas (TCGA) indicated that the NET score and TF value are independent prognostic factors for RCC patients. Collectively, NETs formed by intravascular neutrophils further activate the coagulation system. Both the DNA scaffold sprouted and fibrin net triggered by NETs anchor and shield CTCs from attack. Thus, degrading this framework maybe could destroy the double shelter of CTCs, the pioneers of metastasis.

Oncolytic herpes simplex virus tumor targeting and neutralization escape by engineering viral envelope glycoproteins

Oncolytic herpes simplex viruses (oHSVs) have been approved for clinical usage and become more and more popular for tumor virotherapy. However, there are still many issues for the oHSVs used in clinics and clinical trials. The main issues are the limited anti-tumor effects, intratumor injection, and some side effects. To overcome such challenges, here we review the genetic engineering of the envelope glycoproteins for oHSVs to target tumors specifically, and at the same time we summarize the many neutralization antibodies against the envelope glycoproteins and align the neutralization epitopes with functional domains of the respective glycoproteins for future identification of new functions of the glycoproteins and future engineering of the epitopes to escape from host neutralization.

Identification of Putative UL54 (ICP27) Transcription Regulatory Sequences Binding to Oct-1, v-Myb, Pax-6 and Hairy in Herpes Simplex Viruses

An oncolytic herpes simplex virus (oHSV) has proven amenable in oncolytic virotherapy and was approved to treat melanoma. The immediate-early (IE) protein ICP27 encoded by gene UL54 is essential for HSV infection. Post-transcriptional modification of UL54 would increase tumor targeting of oHSVs. However, UL54 gene transcription regulatory sequences and factors were not reported yet. Here we isolated a new strain LXMW of type 1 HSV (HSV-1-LXMW) in China and found it's closely related to HSV-1 strains Patton and H129 in the US by the first and next generation DNA sequencing viral DNA phylogenetic analysis. Using a weight matrix-based program Match, we found the UL54 transcription regulatory sequences binding to the transcription factors Oct-1, v-Myb and Pax-6 in HSV-1-LXMW, while the sequences binding to Oct-1 and Hairy in a HSV-2 strain. Further validation showed that HSV-1 and HSV-2 shared the common sequence binding to Oct-1, but had unique sequences to bind v-Myb and Pax-6, or Hairy, respectively, by DNA sequence alignment of total 11 HSV strains. The published results howed that the expression of transcription factors is consistent with the tissue tropism of HSV-1 and HSV-2. In the current article a new HSV-1 strain LXMW was isolated and its putative HSV UL54 transcription regulatory sequences and factors were identified for the first time. Our findings highlight the new understanding of the principles of transcriptional regulation in HSV biology and oncolytic virotherapy.

Circulating tumor cells in the pulmonary vein increase significantly after lobectomy: A prospective observational study

Background

It has been reported that there are more circulating tumor cells (CTCs) in the pulmonary vein (PV) than in the peripheral blood; however, it is unclear whether the CTC count changes in the PV after resection of a lung lobe.

Methods

Thirty‐three lung cancer patients were recruited for the study, including 17 who underwent lobectomy via video‐assisted thoracoscopic surgery and 16 via open thoracotomy. Sixty‐six blood specimens were sampled from the PV before the PV was interrupted and after lobectomy. The CTCs were quantified using the oHSV1‐hTERT‐GFP method.

Results

Before PV interruption, the CTC (pre‐CTC) detection rate was 79.0% (26/33), the mean number of CTCs was 3.36 (median 2, range: 0–18), and there was no significant relationship between the pre‐CTC count and clinical factors, such as histologic findings and pathological T stage (P > 0.05). After lobectomy, the CTC (post‐CTC) detection rate was 100% (33/33), the average number of CTCs was 14.88 (median 11, range: 1–69), and the post‐CTC count was significantly higher in patients in whom the PV was interrupted prior to the pulmonary artery (PA) than in patients in whom the PA was interrupted before the PV (P = 0.016). Overall, the CTC count was significantly higher following surgery (P < 0.001).

Conclusion

Post‐CTC counts were significantly higher than pre‐CTC counts, suggesting that surgical manipulation may potentially dislodge tumor cells into the PV. Interrupting the PV prior to the PA during lobectomy may prevent partial CTC entry into the circulation.

[Progress of Liquid Biopsy in Early Diagnosis of Lung Cancer]

肺癌的早期诊断有利于提高患者的生存率。应用影像学方法对肺癌高风险人群进行筛查，可以起到早发现、早诊断的作用。越来越多的研究显示，液体活检（liquid biopsy）可以对该方法进行替代和补充。检测肺癌患者外周血中的循环肿瘤细胞（circulating tumor cells, CTCs）、循环肿瘤DNA（circulating tumor DNA, ctDNA）、微小核糖核酸（microRNA, miRNA）、外泌体（exosomes）、肿瘤血小板（tumor educated platelets, TEPs）可以用于肺癌的早期诊断，并且可能为影像学检查阴性的高风险人群提供相应的诊疗建议。全文就以上标志物的检测手段、在肺癌早期诊断中的价值以及存在优势与局限性进行综述，以期促进液体活检在肺癌早期诊断、与其他筛查手段相结合方面的应用。

Trial Watch: Oncolytic viro-immunotherapy of hematologic and solid tumors

Oncolytic viruses selectively target and kill cancer cells in an immunogenic fashion, thus supporting the establishment of therapeutically relevant tumor-specific immune responses. In 2015, the US Food and Drug Administration (FDA) approved the oncolytic herpes simplex virus T-VEC for use in advanced melanoma patients. Since then, a plethora of trials has been initiated to assess the safety and efficacy of multiple oncolytic viruses in patients affected with various malignancies. Here, we summarize recent preclinical and clinical progress in the field of oncolytic virotherapy.

Isolation and molecular analysis of circulating tumor cells from lung cancer patients using a microfluidic chip type cell sorter

Circulating tumor cells (CTCs) are a tumor‐derived material utilized for liquid‐based biopsy; however, capturing rare CTCs for further molecular analysis remains technically challenging, especially in non‐small‐cell lung cancer. Here, we report the results of a clinical evaluation of On‐chip Sort, a disposable microfluidic chip‐based cell sorter, for capture and molecular analysis of CTCs from patients with lung adenocarcinoma. Peripheral blood was collected from 30 metastatic lung adenocarcinoma patients to enumerate CTCs using both On‐chip Sort and CellSearch in a blind manner. Captured cells by On‐chip Sort were subjected to further molecular analysis. Peripheral blood samples were also used for detection of EGFR mutations in plasma using droplet digital PCR. Significantly more CTCs were detected by On‐chip Sort (22/30; median 5; range, 0–18 cells/5 mL blood) than by CellSearch (9/30; median, 0; range, 0–12 cells/7.5 mL) (P < 0.01). Thirteen of 30 patients who had a negative CTC count by CellSearch had a positive CTC count by On‐chip Sort. EGFR mutations in CTCs captured by On‐chip Sort were observed in 40.0% (8/20) of patients with EGFR‐mutated primary tumor. EGFR mutations were often observed in 53.3% (8/15) of patients detected in plasma DNA. Expressions of EGFR and vimentin protein on CTCs were also successfully assessed using On‐chip Sort. These results suggest that On‐chip Sort is an efficient method to detect and capture rare CTCs from patients with lung adenocarcinoma that are undetectable with CellSearch. Mutation detection using isolated CTCs remains to be further tackled (UMIN000012488).

Circulating Tumor Cell Assessment in Presumed Early Stage Non-Small Cell Lung Cancer Patients Treated with Stereotactic Body Radiation Therapy: A Prospective Pilot Study

PURPOSE

In patients treated with stereotactic body radiation therapy (SBRT) for presumed early stage non-small cell lung cancer (NSCLC), detection and monitoring of circulating tumor cells (CTCs) may be useful for assessing treatment response safely and noninvasively. No published reports of CTC trends in this patient population exist to date.

METHODS AND MATERIALS

Patients with clinically diagnosed stage I NSCLC treated with SBRT were eligible for this institutional review board-approved prospective clinical trial. Peripheral blood samples were assayed for CTCs via a green fluorescent protein-expressing adenoviral probe. CTC positivity was defined as 1.3 green fluorescent protein-positive cells/mL of collected blood. Samples were obtained before (pre-radiation therapy [RT]), during, and after SBRT (post-RT; months 1, 3, 6, 12, 18, and 24). SBRT was delivered in ≤5 fractions (median dose of 50 Gy in 12.5 Gy fractions) to a biological equivalent dose of ≥100 Gy in all cases.

RESULTS

Forty-eight consecutive patients (T1a [73%], T1b [21%], and T2a [6%]) were enrolled. Median follow-up was 14.2 months. Twenty patients (42%) had a positive CTC level pre-RT, with a median CTC count of 4.2 CTCs per mL (interquartile range [IQR], 2.2-18.7). Of these 20 patients, 17 had evaluable post-RT CTC evaluations showing reduced CTC counts at 1 month (median, 0.2; IQR, 0.1-0.8) and 3 months (median, 0.6; IQR, 0-1.1). Three of these 17 patients experienced disease progression at a median of 19.9 months; all 3 experienced ≥1 positive post-RT CTC test predating clinical progression by a median of 16 months (range, 2-17 months). In contrast, among patients presenting with CTC-detectable disease and for whom all post-RT CTC tests were negative, none experienced recurrence or progression.

CONCLUSIONS

CTC monitoring after SBRT for presumed early stage NSCLC may give lead-time notice of disease recurrence or progression. Conversely, negative CTC counts after treatment may provide reassurance of disease control. CTC analysis is thus potentially useful in enhancing clinical diagnosis and follow-up in this population.

Single nucleotide variant profiles of viable single circulating tumour cells reveal CTC behaviours in breast cancer

Circulating tumour cell (CTC) behaviours are distinct from those of bulk tissues. Thus, treatments to eliminate CTCs differ from the regimens followed to reduce the primary tumour and its metastases. Accordingly, comprehensively deciphering the single nucleotide variant (SNV) profiles in CTCs, which partially determine CTC behaviours, is a priority. Using viable CTCs isolated with the oHSV1-hTERT-GFP virus coupled with fluorescence-activated cell sorting (FACS), the whole genome was amplified using the multiple annealing and looping-based amplification cycle (MALBAC) method. CTC behaviours were evaluated using the SNVs found to be recurrently mutated in different cells (termed CTC-shared SNVs). Analysis of the sequencing data of 11 CTCs from 8 patients demonstrated that SNVs accumulated sporadically among CTCs and their matched primary tumours (22 co-occurring mutated genes were identified in the exomes of CTCs and their matched primary tissues and metastases), and 394 SNVs were shared by at least two CTCs. Mutated APC and LRP1B genes co-occurred in CTC-shared and bulk-tissue SNVs. Additionally, the breast-originating identity of the CTC-shared SNVs was verified, and they demonstrated the following CTC behaviours: i) intravasation competency; ii) increased migration or motility; iii) enhanced cell-cell interactions; iv) variation in energy metabolism; v) an activated platelet or coagulation system; and vi) dysfunctional mitosis. These results demonstrated that it is feasible to capture and amplify the genomes of single CTCs using the described pipeline. CTC-shared SNVs are a potential signature for identifying the origin of the primary tumour in a liquid biopsy. Furthermore, CTCs demonstrated some behaviours that are unique from those of bulk tissues. Therefore, therapies to eradicate these precursors of metastasis may differ from the existing traditional regimens.

Detection of circulating tumor cells using oHSV1-hTERT-GFP in lung cancer

BACKGROUND

This study was conducted to evaluate the clinical utility of the oHSV1-hTERT-GFP circulating tumor cell (CTC) detection method in the peripheral blood of patients with lung cancer by comparing its sensitivity to the CellSearch CTC detection method.

METHODS

The oHSV1-hTERT-GFP and CellSearch CTC detection methods were compared using peripheral blood samples of patients pathologically diagnosed with lung cancer.

RESULTS

A total of 240 patients with lung cancer were recruited, including 89 patients who were newly diagnosed and 151 patients who had previously received treatment. Sixty-six newly diagnosed patients were evaluated using both methods. The CTC detection rates were 71.2% and 33.3% using the oHSV1-hTERT-GFP and CellSearch methods, respectively; this difference was statistically significant (P = 0.000). Among the entire cohort (n = 240), the CTC detection rate using the oHSV1-hTERT-GFP method was 76.3%, with a CTC count of 0-81. The CTC detection rates were 76.7%, 68.9%, and 76.3% in patients with squamous cell carcinoma, adenocarcinoma, and small cell lung cancer, respectively. There was no statistically significant difference in the CTC detection rates between these different pathological subtypes (P = 0.738). The CTC detection rates of 79.8% and 74.4% in patients with stage I-III and IV lung cancer, respectively, were not significantly different (P = 0.427).

CONCLUSION

The oHSV1-hTERT-GFP method is highly effective for detecting CTCs in patients with lung cancer, independent of pathological type and disease stage, and is ideal for large-scale clinical applications.

[Research Progresses of Circulating Tumor Cells in Diagnosis and Treatment of Early Lung Cancer]

循环肿瘤细胞（circulating tumor cells, CTCs）作为液体活检的一种重要类型，在肺癌的筛查诊断、疗效评估、术后监测与预后判断等方面显示出越来越丰富的临床价值。随着对肺癌高危人群筛查工作的进展，大量肺小结节患者被检出，但是肺小结节不等于肺癌，而且据统计良性比例达90%-95%，这使得该部分患者在首次就诊时的良恶性鉴别诊断成为临床医生面临着的新的机遇与挑战。CTCs检测技术的不断进步与完善，是否可以在早期肺癌的鉴别诊断中发挥更大的作用，此外，它是否对早期肺癌手术治疗时的操作具有指导意义，这还需要进一步科研探索，以期将来实现临床转化。

The Potential for Circulating Tumor Cells in Pancreatic Cancer Management

Pancreatic cancer is one the most lethal malignancies. Only a small proportion of patients with this disease benefit from surgery. Chemotherapy provides only a transient benefit. Though much effort has gone into finding new ways for early diagnosis and treatment, average patient survival has only been improved in the order of months. Circulating tumor cells (CTCs) are shed from primary tumors, including pre-malignant phases. These cells possess information about the genomic characteristics of their tumor source in situ, and their detection and characterization holds potential in early cancer diagnosis, prognosis, and treatment. Liquid Biopsies present an alternative to tumor biopsy that are hard to sample. Below we summarize current methods of CTC detection, the current literature on CTCs in pancreatic cancer, and future perspectives.

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Background

Convenient approaches for accurate biopsy are extremely important to the diagnosis of lung cancer. We aimed to systematically review the clinical updates and development trends of approaches for biopsy, i.e., CT-guided PTNB (Percutaneous Transthoracic Needle Biopsy), ENB (Electromagnetic Navigation Bronchoscopy), EBUS-TBNA (Endobroncheal Ultrasonography-Transbronchial Needle Aspiration), mediastinoscopy and CTC (Circulating Tumor Cell).

Methods

Medline and manual searches were performed. We identified the relevant studies, assessed study eligibility, evaluated methodological quality, and summarized diagnostic yields and complications regarding CT-guided PTNB (22 citations), ENB(31 citations), EBUS-TBNA(66 citations), Mediastinoscopy(15 citations) and CTC (19 citations), respectively.

Results

The overall sensitivity and specificity of CT-guided PTNB were reported to be 92.52% ± 3.14% and 97.98% ± 3.28%, respectively. The top two complications of CT-guided PTNB was pneumothorax (946/4170:22.69%) and hemorrhage (138/1949:7.08%). The detection rate of lung cancer by ENB increased gradually to 79.79% ± 15.34% with pneumothorax as the top one complication (86/1648:5.2%). Detection rate of EBUS-TBNA was 86.06% ± 9.70% with the top three complications, i.e., hemorrhage (53/8662:0.61%), pneumothorax (46/12432:0.37%) and infection (34/11250:0.30%). The detection rate of mediastinoscopy gradually increased to 92.77% ± 3.99% with .hoarseness as the refractory complication (4/2137:0.19%). Sensitivity and specificity of CTCs detection by using PCR (Polymerase Chain Reaction) were reported to be 78.81% ± 14.72% and 90.88% ± 0.53%, respectively.

Conclusion

The biopsy approaches should be chosen considering a variety of location and situation of lesions. CT-guided PTNB is effective to reach lung parenchyma, however, diagnostic accuracy and incidence of complications may be impacted by lesion size or needle path length. ENB has an advantage for biopsy of smaller and deeper lesions in lung parenchyma. ENB plus EBUS imaging can further improve the detection rate of lesion in lung parenchyma. EBUS-TBNA is relatively safer and mediastinoscopy provides more tissue acquisition and better diagnostic yield of 4R and 7th lymph node. CTC detection can be considered for adjuvant diagnosis.