Prognostic value of circulating tumor cells combined with neutrophil-lymphocyte ratio in patients with hepatocellular carcinoma

BACKGROUND Circulating tumor cell(CTC)count and neutrophil-to-lymphocyte ratio(NLR)are both closely associated with the prognosis of hepatocellular carcinoma(HCC).AIM To investigate the prognostic value of combining these two indicators in HCC.METHODS Clinical data were collected from patients with advanced HCC who received im-mune therapy combined with targeted therapy at the Department of Oncology,the Affiliated Hospital of Southwest Medical University,Sichuan,China,from 2021 to 2023.The optimal cutoff values for CTC programmed death-ligand 1(PD-L1)(+)>1 or CTC PD-L1(+)≤1 and NLR>3.89 or NLR≤3.89 were evaluated using X-Tile software.Patients were categorized into three groups based on CTC PD-L1(+)counts and NLR:CTC-NLR(0),CTC-NLR(1),and CTC-NLR(2).The relationship between CTC-NLR and clinical variables as well as survival rates was assessed.RESULTS Patients with high CTC PD-L1(+)expression or NLR at baseline had shorter median progression-free survival(m-PFS)and median overall survival(mOS)than those with low levels of CTC PD-L1(+)or NLR(P<0.001).Mean-while,patients in the CTC-NLR(2)group showed a significant decrease in mPFS and mOS.Cox regression analysis revealed that alpha-fetoprotein(AFP),CTC PD-L1(+),and CTC-NLR were independent predictors of OS.The time-dependent receiver operating characteristic curve showed that the area under the curve of CTC-NLR at 12 months(0.821)and 18 months(0.821)was superior to that of AFP and CTC PD-L1(+).CONCLUSION HCC patients with high CTC PD-L1(+)or NLR expression tend to exhibit poor prognosis,and a high baseline CTC-NLR score may indicate low survival.CTC-NLR may serve as an effective prognostic indicator for patients with advanced HCC receiving immunotherapy combined with targeted therapy.

Circulating tumor cells as prognostic marker in pancreatic cancer

In this editorial we comment on the article by Zhang et al published in the recent issue of the World Journal of Clinical Oncology.Pancreatic cancer is the fourth most common cause of cancer-related mortality and has the lowest survival rate among all solid cancers.It causes 227000 deaths annually worldwide,and the 5-year survival rate is very low due to early metastasis,which is 4.6%.Cancer survival increases with better knowledge of risk factors and early and accurate diagnosis.Circulating tumor cells(CTCs)are tumor cells that intravasate from the primary tumor or metastasis foci into the peripheral blood circulation system spontan-eously or during surgical operations.Detection of CTC in blood is promising for early diagnosis.In addition,studies have associated high CTC levels with a more advanced stage,and more intensive treatments should be considered in cases with high CTC.In tumors that are considered radiologically resectable,it may be of critical importance in detecting occult metastases and preventing unnecessary surgeries.

Circulating tumor cells(CTCs)in breast cancer:a diagnostic tool for prognosis and molecular analysis

Metastatic breast cancer （MBC） is characterized by a combination of tumor growth, proliferation and metastatic progression and is typically managed with palliative intent. The benefit of standard systemic therapies is relatively limited and the disease is considered incurable suggesting the need to investigate the biological drivers of the various phases of the metastatic process in order to improve the selection of molecularly driven therapies. The detection, enumeration and molecular analysis of circulating tumor cells （CTCs） provide an intriguing opportunity to advance this knowledge. CTCs enumerated by the Food and Drugs Administration-cleared CellSearchTM system are an independent prognostic factor of progression- free survival （PFS） and overall survival （OS） in MBC patients. Several published papers demonstrated the poor prognosis for MBC patients that presented basal CTC count _〉5 in 7.5 mL of blood. Therefore, the enumeration of CTCs during treatment for MBC provides a tool with the ability to predict progression of disease earlier than standard timing of anatomical assessment using conventional radiological tests. During the metastatic process cancer cells exhibit morphological and phenotypic plasticity undergoing epithelial- mesenchymal transition （EMT）. This important phenomenon is associated with down regulation of epithelial marker （e.g., EpCAM） with potential limitations in the applicability of current CTCs enrichment methods. Such observations translated in a number of investigations aimed at improving our capabilities to enumerate and perform molecular characterization of CTCs. Theoretically, the phenotypic analysis of CTCs can represent a ＂liquid＂ biopsy of breast tumor that is able to identify a new potential target against the metastatic disease and advance the development and monitoring of personalized therapies.

Circulating tumor cells and circulating tumor DNA in breast cancer diagnosis and monitoring

Liquid biopsy,including both circulating tumor cells and circulating tumor DNA,is becoming more popular as a diagnostic tool in the clinical management of breast cancer.Elevated concentrations of these biomarkers during cancer treatment may be used as markers for cancer progression as well as to understand the mechanisms underlying metastasis and treatment resistance.Thus,these circulating markers serve as tools for cancer assessing and monitoring through a simple,non-invasive blood draw.However,despite several study results currently noting a potential clinical impact of ctDNA mutation tracking,the method is not used clinically in cancer diagnosis among patients and more studies are required to confirm it.This review focuses on understanding circulating tumor biomarkers,especially in breast cancer.

Recent progress in aptamer-based microfluidics for the detection of circulating tumor cells and extracellular vesicles

Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circulating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based microfluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.

Circulating tumor cells: Biological features and survival mechanisms

Circulating tumor cells(CTCs)are neoplastic cells that are detached from primary tumors and enter circulation.Enumeration and characterization of CTCs are of significance in cancer diagnosis,prognosis,and treatment monitoring.CTC survival in the bloodstream is a limiting step for the development of metastases in distant organs.Recent technological advances,especially in single-cell molecular analyses have uncovered heterogeneous CTC survival mechanisms.Undergoing epithelial-to-mesenchymal transition(EMT),increasing stem cell-like properties,and forming cell clusters enable CTCs to adapt to the harsh microenvironment of the circulation.Expressing and releasing several immunosuppressive molecules help CTCs escape from anti-cancer immune mechanisms.This review article summarizes the biological characteristics of CTCs and focuses on the recent understanding of the mechanisms by which CTCs survive in circulation.Additionally,the clinical and therapeutic implications of CTCs are discussed.

A pilot study of the relative number of circulating tumor cells and leukocytes containing actin-binding proteins in head and neck cancer patients

Circulating tumor cells(CTCs)play an important role in tumor metastases,which is positively correlated with an increased risk of death.Actin-binding proteins,including cofilin(CFL1),profilin 1(PFN1),and adenylate cyclase-associated protein 1(CAP1),are thought to be involved in tumor cell motility and metastasis,specifically in head and neck squamous cell carcinoma(HNSCC).However,currently,there are no published studies on CFL1,PFN1,and CAP1 in CTCs and leukocytes in HNSCC patients.We assessed serum levels of CFL1,PFN1,and CAP1 and the number of CTCs and leukocytes containing these proteins in blood from 31 HNSCC patients(T1-4N0-2M0).The analysis used flow cytometry and an enzyme-linked immunosorbent assay kit.We found that CAP1+CTCs and CAP1+leukocyte subpopulations were prevalent in these HNSCC patient samples,while the prevalence rates of CFL1+and PFN1+CTCs were relatively low.Patients with stage T2-4N1-2M0 had CFL1+and PFN1+CTCs with an elevated PFN1 serum level,compared with the T1-3N0M0 group.In summary,the PFN1 serum level and the relative number of PFN1+CD326+CTCs could be valuable prognostic markers for HNSCC metastases.The current study is the first to obtain data regarding the contents of actin-binding proteins(ABPs)in CTCs,and leukocytes in blood from HNSCC patients.This is also the first to assess the relationship between the number of CTCs subgroups and disease characteristics.

Microfluidic platform for circulating tumor cells isolation and detection

Circulating tumor cells(CTCs)are essential biomarkers for liquid biopsies,which are important in the early screening,prognosis,and real-time monitoring of cancer.However,CTCs are less abundant in the peripheral blood of patients,therefore,their isolation is necessary.Recently,the use of microfluidics for CTC sorting has become a research hotspot owing to its low cost,ease of integration,low sample consumption,and unique advantages in the manipulation of micron-sized particles.Herein,we review the latest research on microfluidics-based CTC sorting.Specifically,we consider active sorting using external fields(electric,magnetic,acoustic,and optical tweezers)and passive sorting using the flow effects of cells in specific channel structures(microfiltration sorting,deterministic lateral displacement sorting,and inertial sorting).The advantages and limitations of each method and their recent applications are summarized here.To conclude,a forward-looking perspective is presented on future research on the microfluidic sorting of CTCs.

Clinical implications and perspectives of portal venous circulating tumor cells in pancreatic cancer

Despite recent improvements in the diagnosis and treatment of pancreatic cancer(PC),clinical outcomes remain dismal.Moreover,there are no effective prognostic or predictive biomarkers or options beyond carbohydrate antigen 19-9 for personalized and precise treatment.Circulating tumor cells(CTCs),as a member of the liquid biopsy family,could be a promising biomarker;however,the rarity of CTCs in peripheral venous blood limits their clinical use.Because the first venous drainage of PC is portal circulation,the portal vein can be a more suitable location for the detection of CTCs.Endoscopic ultrasound-guided portal venous sampling of CTCs is both feasible and safe.Several studies have suggested that the detection rate and number of CTCs may be higher in the portal blood than in the peripheral blood.CTC counts in the portal blood are highly associated with hepatic metastasis,recurrence after surgery,and survival.The phenotypic and genotypic properties measured in the captured portal CTCs can help us to understand tumor heterogeneity and predict the prognosis of PC.Small sample sizes and heterogeneous CTC detection methods limit the studies to date.Therefore,a large number of prospective studies are needed to corroborate portal CTCs as a valid biomarker in PC.

Impact of chronic exposure to bevacizumab on EpCAM-based detection of circulating tumor cells

Background： Circulating tumor cells （CTCs） are often undetected through the immunomagnetic epithelial cell adhesion molecule （EpCAM）-based CellSearch~ System in breast and colorectal cancer （CRC） patients treated with bevacizumab （BEV）, where low CTC numbers have been reported even in patients with evidence of progression of disease. To date, the reasons for this discrepancy have not been clarified. This study was carried out to investigate the molecular and phenotypic changes in CRC cells after chronic exposure to BEV in vitro. Methods： The human CRC cell line WiDr was exposed to a clinically relevant dose of BEV for 3 months in vitro. The expression of epithelial and mesenchymal markers and EpCAM isoforms was determined by western blotting and immunofluorescence. To evaluate the impact of EpCAM variant isoforms expression on CTC enumeration by CellSearch, untreated and treated colon cancer cells were spiked into 7.5 mL of blood from a healthy donor and enumerated by CellSearch. Results： Chronic exposure of CRC cell line to BEV induced decreased expression of EpCAM 40 kDa isoform and increased expression EpCAM 42 kDa isoform, together with a decreased expression of cytokeratins （CK）, while no evidence of epithelial to mesenchymal transition （EMT） in treated cells was observed. The recovery rate of cells through CellSearch was gradually reduced in course of treatment with BEV, being 84% , 70% and 40% at l, 2 and 3 months, respectively. Conclusions： We hypothesize that BEV may prevent CellSearch from capturing CTCs through altering EpCAM isoforms.

Notes for developing a molecular test for the full characterization of circulating tumor cells

The proved association between the circulating tumor cell （CTC） levels and the patients＇ survival parameters has been growing interest to investigate the molecular profile of these neoplastic cells among which hide out precursors capable of initiating a new distant metastatic lesion. The full characterization of the tumor cells in peripheral blood of cancer patients is expected to be of help for understanding and （prospectively） for counteracting the metastatic process. The major hitch that is hampering the successful gaining of this result is the lack of a consensus onto standard operating procedures （SOPs） for performing what we generally define as the ＂liquid biopsy＂. Here we review the more recent acquisitions in the analysis of CTCs and tumor related nucleic acids, looking to the main open questions that are hampering their definitive employ in the routine clinical practice.

Evaluation of epithelial-mesenchymal transitioned circulating tumor cells in patients with resectable gastric cancer: Relevance to therapy response

AIM: To evaluate the epithelial-to-mesenchymal transition(EMT) of circulating tumor cells(CTCs) in gastric cancer patients.METHODS: We detected tumor cells for expression of four epithelial(E^+) transcripts(keratins 8, 18, and 19 and epithelial cell adhesion molecule) and two mesenchymal(M^+) transcripts(Vimentin and Twist) by a quantifiable, dual-colorimetric RNA-in situ hybridization assay. Between July 2014 and October 2014, 44 patients with gastric cancer were recruited for CTC evaluation. Blood samples were obtained from selected patients during the treatment course [before surgery, after surgery and at the 6^(th) cycle of XELOX based chemotherapy(about 6 mo postoperatively)].RESULTS: We found the EMT phenomenon in which there were a few biphenotypic E^+/M^+ cells in primary human gastric cancer specimens. Of the 44 patients, the presence of CTCs was reported in 35(79.5%) patients at baseline. Five types of cells including from exclusively E^+ CTCs to intermediate CTCs and exclusively M^+ CTCs were identified(4 patients with M^+ CTCs and 10 patients with M^+ or M^+ > E^+ CTCs). Further, a chemotherapy patient having progressive disease showed a proportional increase of mesenchymal CTCs in the post-treatment blood specimens. We used NCI-N87 cells to analyze the linearity and sensitivity of Can Patrol^(TM) system and the correlation coefficient(R^2) was 0.999.CONCLUSION: The findings suggest that the EMT phenomenon was both in a few cells of primary tumors and abundantly in CTCs from the blood of gastric cancer patients, which might be used to monitor therapy response.

Prognostic and predictive blood biomarkers in gastric cancer and the potential application of circulating tumor cells

Gastric cancer(GC), with its high incidence and mortality rates, is a highly fatal cancer that is common in East Asia particularly in China. Its recurrence and metastasis are the main causes of its poor prognosis. Circulating tumor cells(CTCs) or other blood biomarkers that are released into the circulating blood stream by tumors are thought to play a crucial role in the recurrence and metastasis of gastric cancer. Therefore, the detection of CTCs and other blood biomarkers has an important clinical significance; in fact, they can help predict the prognosis, assess the staging, monitor the therapeutic effects and determine the drug susceptibility. Recent research has identified many blood biomarkers in GC, such as various serum proteins, autoantibodies against tumor associated antigens, and cell-free DNAs. The analysis of CTCs and circulating cell-free tumor DNA(ctDNA) in the peripheral blood of patients with gastric cancer is called as liquid biopsy. These blood biomarkers provide the disease status for individuals and have clinical meaning. In this review, we focus on the recent scientific advances regarding CTCs and other blood biomarkers, and discuss their origins and clinical meaning.

Circulating tumor cells in pancreatic cancer patients:Enrichment and cultivation

AIM:To investigate the feasibility of separation and cultivation of circulating tumor cells(CTCs)in pancreatic cancer(Pa C)using a filtration device.METHODS:In total,24 Pa C patients who were candidates for surgical treatment were enrolled into the study.Peripheral blood samples were collected before an indicated surgery.For each patient,approximately8 m L of venous blood was drawn from the antecubitalveins.A new size-based separation Meta Cell?technology was used for enrichment and cultivation of CTCs in vitro.(Separated CTCs were cultured on a membrane in FBS enriched RPMI media and observed by inverted microscope.The cultured cells were analyzed by means of histochemistry and immunohistochemistry using the specific antibodies to identify the cell origin.RESULTS:CTCs were detected in 16 patients(66.7%)of the 24 evaluable patients.The CTC positivity did not reflect the disease stage,tumor size,or lymph node involvement.The same percentage of CTC positivity was observed in the metastatic and non-metastatic patients(66.7%vs 66.7%).We report a successful isolation of CTCs in Pa C patients capturing proliferating cells.The cells were captured by a capillary action driven size-based filtration approach that enabled cells cultures from the viable CTCs to be unaffected by any antibodies or lysing solutions.The captured cancer cells displayed plasticity which enabled some cells to invade the separating membrane.Further,the cancer cells in the"bottom fraction",may represent a more invasive CTC-fraction.The CTCs were cultured in vitro for further downstream applications.CONCLUSION:The presented size-based filtration method enables culture of CTCs in vitro for possible downstream applications.

Molecular detection of epithelial-mesenchymal transition markers in circulating tumor cells from pancreatic cancer patients:Potential role in clinical practice

AIM To evaluate the clinical properties of three subpopulations of circulating tumor cells(CTCs) undergoing epithelial-mesenchymal transition(EMT) in pancreatic ductal adenocarcinoma(PDAC) patients.METHODS We identified CTCs for expression of the epithelial cell marker cytokeratin or epithelial cell adhesion molecule(EpCAM)(E-CTC), the mesenchymal cell markers vimentin and twist(M-CTC), or both(E/M-CTC) using the CanPatrol system. Between July 2014 and July 2016, 107 patients with PDAC were enrolled for CTC evaluation. CTC enumeration and classification were correlated with patient clinicopathological features and outcomes.RESULTS CTCs were detected in 78.5% of PDAC patients. The number of total CTCs ranged from 0 to 26 across all 107 patients, with a median value of six. CTC status correlated with lymph node metastasis, TNM stage, distant metastasis, blood lymphocyte counts, and neutrophil-to-lymphocyte ratio(NLR). Kaplan-Meier survival analysis showed that patients with ≥ 6 total CTCs had significantly decreased overall survival and progression-free survival compared with patients with < 6 total CTCs. The presence of M-CTCs was positively correlated with TNM stage(P < 0.01) and distant metastasis(P < 0.01). Additionally, lymphocyte counts and NLR in patients without CTCs were significantly different from those in patients testing positive for each CTC subpopulation(P < 0.01).CONCLUSION Classifying CTCs by EMT markers helps to identify the more aggressive CTC subpopulations and provides useful evidence for determining a suitable clinical approach.

Liquid biopsy in patients with pancreatic cancer: Circulating tumor cells and cell-free nucleic acids

Despite recent advances in surgical techniques and perioperative management, the prognosis of pancreatic cancer(PCa) remains extremely poor. To provide optimal treatment for each patient with Pca, superior biomarkers are urgently needed in all phases of management from early detection to staging, treatment monitoring, and prognosis. In the blood of patients with cancer, circulating tumor cells(CTCs) and cell-free nucleic acids(cf NAs), such as DNA, m RNA, and noncoding RNA have been recognized. In the recent years, their presence in the blood has encouraged researchers to investigate their potential use as novel blood biomarkers, and numerous studies have demonstrated their potential clinical utility as a biomarker for certain types of cancer. This concept, called "liquid biopsy" has been focused on as a less invasive, alternative approach to cancer tissue biopsy for obtaining genetic and epigenetic aberrations that contribute to oncogenesis and cancer progression. In this article, we review the available literature on CTCs and cfN As in patients with cancer, particularly focusing on PCa, and discuss future perspectives in this field.

Circulating tumor and cancer stem cells in hepatitis C virusassociated liver disease

AIM:To assess the role of circulating tumor cells(CTCs)and cancer stem cells(CSCs)in hepatitis C virus(HCV)-associated liver disease.METHODS:Blood and/or tissue samples were obtained from HCV(genotype 4)-associated hepatocellularcarcinoma patients(HCC;n=120),chronic hepatitis C patients(CH;n=30)and 33 normal control subjects(n=33).Serum levels of alpha-fetoprotein(AFP),alkaline phosphatase,and alanine and aspartate aminotransferases were measured.Cytokeratin 19(CK19)monoclonal antibody was used to enumerate CTCs,and CD133 and CD90 were used to enumerate CSCs by flow cytometry.The expression levels of the CSCs markers(CD133 and CD90)as well as telomerase,melanoma antigen encoding gene 1(MAGE1)and MAGE3 were assessed by RTPCR and quantitative real-time polymerase chain reactions.The number of CTCs and/or the expression levels of CK19,CD133,telomerase,MAGE1 and MAGE3 were correlated to the standard clinicopathologic prognostic factors and disease progression.RESULTS:Levels of AFP,alkaline phosphatase and aspartate aminotransferase were significantly different among the HCC,CH and control groups(P<0.001),whereas alanine aminotransferase differed significantly between patient(HCC and CH)and control groups(P<0.001).At the specified cutoff values determine by flow cytometry,CK19(49.8),CD90(400)and CD133(73)were significantly higher in the blood of HCC patients compared to those in the CH and control groups(P<0.001).On the other hand,CD133 at a 69.5 cutoff was significantly higher in the CH compared to the control group(P≤0.001).Telomerase,MAGE1 and MAGE3RNA were expressed in 55.71%,60.00%and 62.86%of the HCC patients,respectively,but were not detected in patients in the CH or control groups,which were statistically significant(Ps<0.001).The expression levels of telomerase,CD90,MAGE3,CD133 and CK19 were all significantly associated with high tumor grade and advanced stage in HCC patients(all P s<0.05).CONCLUSION:CTC counts and AFP,CK19,telomerase,and MAGE1/MAGE3 expression predict disease progression in patients with HCV,whereas telomerase,MAGE3,CD90,CD133 and CK19 are prognostic mark-

Aneuploidy of chromosome 8 in circulating tumor cells correlates with prognosis in patients with advanced gastric cancer

Objective： Previous work indicated that aneuploidy of chromosome 8 in circulating tumor cells（CTCs）correlated with therapeutic efficacy for advanced gastric cancer（AGC） patients. In this follow-up study performed on the same population of AGC patients, we investigated whether and how aneuploidy of chromosome 8 in CTCs correlates with patients＇ clinical prognosis.Methods： The prospective study was performed on 31 patients with newly diagnosed AGC. Previously established integrated subtraction enrichment（SE） and immunostaining-fluorescence in situ hybridization（i FISH）platform was applied to identify, enumerate and characterize CTCs. Quantification of CTCs and analysis of their aneuploidy of chromosome 8 were performed on patients before and after therapy.Results： CTCs were measured in 93.5% of AGC patients, and two CTC subtypes with diverse threshold values were identified, multiploid CTCs with the threshold of ≥2 per 7.5 m L and multiploid plus triploid CTCs with the threshold of ≥4, which were found to significantly correlate with poor progression-free survival（PFS） and overall survival（OS）. In particular, patients with ≥10% increased multiploid CTCs after an initial 6 weeks of therapy had poor PFS and OS, whereas improved PFS and OS were observed on those who had ≥10% decreased multiploid CTCs. After adjusting for clinically significant factors, ≥10% increased post-therapy multiploid CTCs was the only independent predictor of PFS and OS.Conclusions： Aneuploidy of CTCs correlates with prognosis of AGC patients. Quantitative comparison monitoring multiploid CTCs before and after therapy may help predict improved or inferior prognosis and chemoresistance.

Cryopreservation for delayed circulating tumor cell isolation is a valid strategy for prognostic association of circulating tumor cells in gastroesophageal cancer

AIM To demonstrate the feasibility of cryopreservation of peripheral blood mononuclear cells(PBMCs) for prognostic circulating tumor cell(CTC) detection in gastroesophageal cancer.METHODS Using 7.5 m L blood samples collected in EDTA tubes from patients with gastroesopheagal adenocarcinoma, CTCs were isolated by epithelial cell adhesion molecule based immunomagnetic capture using the Iso Flux platform. Paired specimens taken during the same blood draw(n = 15) were used to compare number of CTCs isolated from fresh and cryopreserved PBMCs. Blood samples were processed within 24 h to recover the PBMC fraction, with PBMCs used for fresh analysis immediately processed for CTC isolation. Cryopreservation of PBMCs lasted from 2 wk to 25.2 mo(median 14.6 mo). CTCs isolated from pre-treatment cryopreserved PBMCs(n = 43) were examined for associations with clinicopathological variables and survival outcomes.RESULTS While there was a significant trend to a decrease in CTC numbers associated with cryopreserved specimens(mean number of CTCs 34.4 vs 51.5, P = 0.04), this was predominately in samples with a total CTC count of > 50, with low CTC count samples less affected(P = 0.06). There was no significant association between the duration of cryopreservation and number of CTCs. In cryopreserved PBMCs from patient samples prior to treatment, a high CTC count(> 17) was associated with poorer overall survival(OS)(n = 43, HR = 4.4, 95%CI: 1.7-11.7, P = 0.0013). In multivariate analysis, after controlling for sex, age, stage, ECOG performance status, and primary tumor location, a high CTC count remained significantly associated with a poorer OS(HR = 3.7, 95%CI: 1.2-12.4, P = 0.03). CONCLUSION PBMC cryopreservation for delayed CTC isolation is a valid strategy to assist with sample collection, transporting and processing.

Advances in isolation and detection of circulating tumor cells based on microfluidics

Circulating tumor cells(CTCs) are the cancer cells that circulate in the peripheral blood after escaping from the original or metastatic tumors. CTCs could be used as non-invasive source of clinical information in early diagnosis of cancer and evaluation of cancer development. In recent years, CTC research has become a hotspot field wherein many novel CTC detection technologies based on microfluidics have been developed. Great advances have been made that exhibit obvious technical advantages, but cannot yet satisfy the current clinical requirements. In this study, we review the main advances in isolation and detection methods of CTC based on microfluidics research over several years, propose five technical indicators for evaluating these methods, and explore the application prospects. We also discuss the concepts, issues, approaches, advantages, limitations, and challenges with an aim of stimulating a broader interest in developing microfluidics-based CTC detection technology.