Folate Receptor-Positive Circulating Tumor Cell Detected by LT-PCR-Based Method as a Diagnostic Biomarker for Non-Small-Cell Lung Cancer. J Thorac Oncol. 2015;10:1163-1171. [PMID: 26200270 DOI: 10.1097/JTO.0000000000000606]

Circulating Tumor Cell Number Is Associated with Primary Tumor Volume in Patients with Lung Adenocarcinoma

Background

Circulating tumor cells (CTCs) are frequently detected in patients with advanced-stage malignant tumors and could act as a predictor of poor prognosis. However, there is a paucity of data on the relationship between CTC number and primary tumor volume in patients with lung cancer. Therefore, our study aimed to evaluate the relationship between CTC number and primary tumor volume in patients with lung adenocarcinoma.

Methods

We collected blood samples from 21 patients with treatment-naive lung adenocarcinoma and 73 healthy individuals. To count CTCs, we used a CTC enrichment method based on fluid-assisted separation technology. We compared CTC numbers between lung adenocarcinoma patients and healthy individuals using propensity score matching, and performed linear regression analysis to analyze the relationship between CTC number and primary tumor volume in lung adenocarcinoma patients.

Results

CTC positivity was significantly more common in lung adenocarcinoma patients than in healthy individuals (p<0.001). The median primary tumor volume in CTC-negative and CTC-positive patients was 10.0 cm³ and 64.8 cm³, respectively. Multiple linear regression analysis showed that the number of CTCs correlated with primary tumor volume in lung adenocarcinoma patients (β=0.903, p=0.002). Further subgroup analysis showed a correlation between CTC number and primary tumor volume in patients with distant (p=0.024) and extra-thoracic (p=0.033) metastasis (not in patients with distant metastasis).

Conclusion

Our study showed that CTC numbers may be associated with primary tumor volume in lung adenocarcinomas patients, especially in those with distant metastasis.

Circulating Tumor Cell Detection In Epithelial Ovarian Cancer Using Dual-Component Antibodies Targeting EpCAM And FRα

Purpose

Circulating tumor cell (CTC) detection methods based on epithelial cell adhesion molecule (EpCAM) have low detection rates in epithelial ovarian cancer (EOC). Meanwhile, folate receptor alpha (FRα) has high expression in EOC cells. We explored the feasibility of combining FRα and EpCAM as CTC capture targets in EOC.

Patients and methods

EpCAM and FRα antibodies were linked to magnetic nanospheres (MNs) using the principle of carbodiimide chemistry. Blood samples from healthy donor spiked with A2780 ovarian cancer cells were used for detecting the capture rate. Ninety-five blood samples from 30 patients with EOC were used for comparing the positive rate of detection when using anti-EpCAM-MNs alone with that when using combination of anti-EpCAM-MNs and anti-FRα-MNs. Samples from 28 patients initially diagnosed with EOC and 20 patients with ovarian benign disease were used for evaluating the sensitivity and specificity of combination of anti-EpCAM-MNs and anti-FRα-MNs.

Results

Regression analysis between the number of recovered and that of spiked A2780 cells revealed y_EpCAM = 0.535x (R² = 0.99), y_FRα = 0.901x (R² = 0.99), and y_EpCAM+FRα = 0.928x (R² = 0.99). In mixtures of A2780 and MCF7 cells, the capture rate was 92% using the combination of anti-EpCAM-MNs and anti-FRα-MNs, exceeding the rate when using anti-EpCAM-MNs or anti-FRα-MNs alone by approximately 20% (P < 0.01). The combination of anti-EpCAM-MNs and anti-FRα-MNs showed a significantly increased positive rate of CTC detection in EOC patients compared with anti-EpCAM-MNs alone (χ² = 14.45, P < 0.001). Sensitivity values were 0.536 and 0.75 and specificity values were 0.9 and 0.85 when using anti-EpCAM-MNs alone and when using the combination of anti-EpCAM-MNs and anti-FRα-MNs, respectively.

Conclusion

The combination of FRα and EpCAM is feasible as a CTC capture target of CTC detection in patients with EOC.

Prognostic and therapeutic significance of circulating tumor cells in patients with lung cancer

BACKGROUND

Lung cancer is the second most common cancer and the main cause of cancer-related mortality worldwide. In spite of various efforts that have been made to facilitate the early diagnosis of lung cancer, most patients are diagnosed when the disease is already in stage IV, which is generally associated with the occurrence of distant metastases and a poor survival. Moreover, a large proportion of these patients will relapse after treatment, heralding the need for the stratification of lung cancer patients in addition to identifying those who are at a higher risk of relapse and, thus, require alternative and/or additional therapies. Recently, circulating tumor cells (CTCs) have been considered as valuable markers for the early diagnosis, prognosis and risk stratification of cancer patients, and they have been found to be able to predict the survival of patients with various types of cancer, including lung cancer. Additionally, the characterization of CTCs has recently provided fascinating insights into the heterogeneity of tumors, which may be instrumental for the development of novel targeted therapies.

CONCLUSIONS

Here we review our current understanding of the significance of CTCs in lung cancer metastasis. We also discuss prominent studies reporting the utility of enumeration and characterization of CTCs in lung cancer patients as prognostic and pharmacodynamic biomarkers for those who are at a higher risk of metastasis and drug resistance.

The Prognostic Values Of Circulating Tumor Cells In Lung Carcinoma: An Analysis On 98 Chinese Patients

Aim

To examine the prognostic values of circulating tumor cells (CTCs) in patients with advanced lung cancer.

Patients and methods

A total of 98 patients with their CTCs enumerated in 2017 was recruited. Data were retrieved from medical records for comparison. Patients’ overall survival (OS) and progression-free survival (PFS) were studied using Kaplan-Meier curve with log rank test.

Results

Seventy-three percent of the patients were male, and nearly half of the patients (44.8%) were smokers. Most tumors were adenocarcinoma (73.4%), and about 60% of the cases were diagnosed at stage IV. Half of the patients showing less than nine CTCs. Patients’ OS were significantly associated with total CTC count (P=0.047), epithelial CTC count (P=0.027), mixed CTC count (P=0.004), and use of adjuvant chemotherapy (P=0.001). For PFS, it was strongly associated with tumor backgrounds (T stage, P=0.002; M stage, P=0.001; TMN stage, P<0.001), cancer biomarkers (CEA, P=0.004; CA125, P=0.004; CA153, P=0.045), and treatment strategy (surgical intervention, P=0.025; first-line chemotherapy, P<0.001).

Conclusion

The present study clearly indicated the significant associations between CTC and overall survival of patients with lung cancer.

Validation of the diagnostic efficiency of folate receptor-positive circulating tumor cells in lung cancers: a prospective observational study

Background

This study sought to validate the clinical value of folate receptor-positive circulating tumor cell (FR+CTC) for the diagnosis of lung cancers.

Methods

Seventy-five lung cancer patients and 71 non-malignant participants (including 48 benign lung disease patients and 23 healthy subjects) were enrolled in this study. Three milliliters of the whole blood sample was collected from all the participants (before surgery for cancer patients). FR+CTC analysis was performed using “CytoploRare Detection Kit”. The expression level of serum biomarkers, including carcinoembryonic antigen (CEA), cytokeratin fragment 19 (CYFRA21-1), and neuron-specific enolase (NSE), were also tested in cancer and benign lung disease patients.

Results

The median FR+CTC level in lung cancers (10.5 CTC units/3 mL blood) was significantly higher than that of the non-malignant group (5.9 CTC units/3 mL blood, P<0.0001). No significant difference in FR+CTC level was observed between patients with different age, gender, and pathological subtype (P>0.05), except for clinical stage (stages I–III versus stage IV: P=0.0169). With 7.9 CTC units/3 mL blood as the cut-off threshold, FR+CTC showed superior sensitivity (78.7%) and specificity (81.7%) in the diagnosis of lung cancers. The detection rate of FR+CTC was significantly higher compared to CEA (24.0%), CYFRA21-1 (48.0%), and NSE (16.0%). The diagnostic efficiency of FR+CTC was similar in stage I lung cancers (n=25, sensitivity =68.0% and specificity =90.1%).

Conclusions

Our results support that FR+CTC is an independent and efficacious biomarker in the diagnosis of lung cancers. FR+CTC detection can be used to assist in early-stage thoracic cancer diagnosis.

Circulating tumor cells in patients with lung cancer: developments and applications for precision medicine

Lung cancer is the most common cause of cancer-related deaths, with most patients dying with distant metastases. Circulating tumor cells (CTCs) are cancer cells that have disseminated into the peripheral blood from primary or metastatic sites and present great potentials as prognostic biomarkers for guiding individualized treatment in lung cancer. To date, various methods have been developed to capture CTCs in peripheral blood, and some approaches for the detection of CTC in lung cancer have shown both high sensitivity and specificity. The CTC analyses offer much promise as a real-time 'liquid biopsy' for prognosis evaluation and therapy intervention in lung cancer. In this Review, we present and discuss the current status of CTC detection and applications in lung cancer.

Effect of Vein-First vs Artery-First Surgical Technique on Circulating Tumor Cells and Survival in Patients With Non-Small Cell Lung Cancer: A Randomized Clinical Trial and Registry-Based Propensity Score Matching Analysis

Importance

It is important to develop a surgical technique to reduce dissemination of tumor cells into the blood during surgery.

Objective

To compare the outcomes of different sequences of vessel ligation during surgery on the dissemination of tumor cells and survival in patients with non-small cell lung cancer.

Design, Setting, and Participants

This multicenter, randomized clinical trial was conducted from December 2016 to March 2018 with patients with non-small cell lung cancer who received thoracoscopic lobectomy in West China Hospital, Daping Hospital, and Sichuan Cancer Hospital. To further compare survival outcomes of the 2 procedures, we reviewed the Western China Lung Cancer database (2005-2017) using the same inclusion criteria.

Interventions

Vein-first procedure vs artery-first procedure.

Main Outcomes and Measures

Changes in folate receptor-positive circulating tumor cells (FR+CTCs) after surgery and 5-year overall, disease-free, and lung cancer-specific survival.

Results

A total of 86 individuals were randomized; 22 patients (25.6%) were younger and 64 (74.4%) older than 60 years. Of these, 78 patients were analyzed. After surgery, an incremental change in FR+CTCs was observed in 26 of 40 patients (65.0%) in the artery-first group and 12 of 38 (31.6%) in the vein-first group (P = .003) (median change, 0.73 [interquartile range (IQR), -0.86 to 1.58] FU per 3 mL vs -0.50 [IQR, -2.53 to 0.79] FU per 3 mL; P = .006). Multivariate analysis confirmed that the artery-first procedure was a risk factor for FR+CTC increase during surgery (hazard ratio [HR], 4.03 [95% CI, 1.53-10.63]; P = .005). The propensity-matched analysis included 420 patients (210 with vein-first procedures and 210 with artery-first procedures). The vein-first group had significantly better outcomes than the artery-first group for 5-year overall survival (73.6% [95% CI, 64.4%-82.8%] vs 57.6% [95% CI, 48.4%-66.8%]; P = .002), disease-free survival (63.6% [95% CI, 55.4%-73.8%] vs 48.4% [95% CI, 40.0%-56.8%]; P = .001), and lung cancer-specific survival (76.4% [95% CI, 67.6%-85.2%] vs 59.9% [95% CI, 50.5%-69.3%]; P = .002). Multivariate analyses revealed that the artery-first procedure was a prognostic factor of poorer 5-year overall survival (HR, 1.65 [95% CI, 1.07-2.56]; P = .03), disease-free survival (HR, 1.43 [95% CI, 1.01-2.04]; P = .05) and lung cancer-specific survival (HR = 1.65 [95% CI, 1.04-2.61]; P = .03).

Conclusions and Relevance

Ligating effluent veins first during surgery may reduce tumor cell dissemination and improve survival outcomes in patients with non-small cell lung cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT03436329.

The utility of folate receptor-positive circulating tumor cell in cancer diagnosis in the elderly population

Purpose: Cancer mortality is relatively high in the elderly population. Folate receptor-positive circulating tumor cell (FR+CTC) has proven an effective biomarker for diagnosis of lung cancer and bladder cancer and may be suitable for other cancer types accompanied with a high expression of FR. To date, the diagnostic efficiency of FR+CTC in the elderly population has not been systematically studied. Herein, we sought to investigate the utility of FR+CTC in cancer diagnosis in the elderly population and the influence of comorbidities on FR+CTC levels in such a population.

Patients and methods: A total of 35 cancer patients (including 23 lung cancers, 8 colorectal cancers, and 4 other cancers) and 40 noncancer participants, aged between 80 and 110, were recruited in this study. Three milliliters of pretreatment peripheral blood was collected from each participant for FR+CTC analysis.

Results: Compared to previous studies, the FR+CTC level was slightly higher in the elderly population (median FR+CTC levels in cancer patients versus noncancer participants were 14.3 versus 9.2 CTC U/3 mL, respectively, P=0.0002). With 10.0 CTC U/3 mL as the cut-off value, the sensitivity and specificity of FR+CTC were 85.7% and 65.0%, respectively. In combination with established serum tumor biomarkers, the diagnostic efficiency of FR+CTC further improved (sensitivity=87.9%, specificity=71.8%). Clinical factors including diabetes, cardiovascular diseases, respiratory diseases, cerebral infarction, and cardiac, liver, and kidney function were not associated with the FR+CTC level (P>0.05).

Conclusion: In this exploratory study, we showed that FR+CTC is an effective biomarker for cancer diagnosis in the elderly population. The presence of comorbidities did not affect the diagnostic efficiency of FR+CTC.

Value of folate receptor-positive circulating tumour cells in the clinical management of indeterminate lung nodules: A non-invasive biomarker for predicting malignancy and tumour invasiveness

Background

Non-invasive lung adenocarcinoma could benefit from limited resection, nonetheless, there is a lack of method to determine preoperative tumour invasiveness. We aimed to investigate whether folate receptor-positive circulating tumour cells (FR⁺-CTCs) in combination with maximum tumour diameter (MTD) determines, before surgery, the invasiveness of small-sized, indeterminate solitary pulmonary nodules (SPNs).

Methods

A total of 382 patients with suspicious lung adenocarcinoma on computed tomography who were expected to undergo lung resection were enrolled in this study at three participating institutes and randomly assigned into training and validation cohorts. Before surgery, 3 mL peripheral blood was collected from all participants. FR⁺-CTCs were analyzed using immunomagnetic leukocyte depletion and quantitated by ligand-targeted PCR method. After surgery, the resected tissues were diagnosed by pathologists according to IASLC/ATS/ERS classification.

Findings

FR⁺-CTC levels in the peripheral blood can differentiate benign from malignant nodules with a sensitivity of 78·6%–82·7% and a specificity of 68·8%–78·4%. Both FR⁺-CTC and MTD are independent predictive indices of invasive tumours for lung adenocarcinoma ≤2 cm based on multivariate analyses. Further, FR⁺-CTC count in combination with MTD can differentiate non-invasive cancers from invasive cancers with a sensitivity of 63·6%–81·8% and a specificity of 71·4%–89·7%.

Interpretation

Detection of FR⁺-CTC is a reliable method to differentiate malignancy of indeterminate SPNs. Combining of FR⁺-CTC count and MTD could possibly enhance preoperative determination of the invasiveness of lung nodules and guide surgeons to select limited lung resection and avoid overtreatment for patients with non-invasive lesions.

Fund

None.

Liquid Biopsy Promotes Non-Small Cell Lung Cancer Precision Therapy

The range of potential applications of liquid biopsies for non-small cell lung cancer management is expanded by the use of circulating tumor deoxyribonucleic acid and circulating tumor cells. Principal studies have demonstrated the predictive accuracy of droplet digital polymerase chain reaction detection, next-generation sequencing, and circulating tumor cells detection in patients with non-small cell lung cancer. The translational potential of these liquid biopsy technologies promotes the improvement of sensitivity and specificity in genomic and molecular methods. Here, we highlight the realities and challenges associated with the use of liquid biopsies for the detection of non-small cell lung cancer in patients. However, liquid biopsy technologies including circulating tumor cells detection, droplet digital polymerase chain reaction detection, and next-generation sequencing detection for precision therapy in non-small cell lung cancer will show substantive clinical applications in the future.

Label-free rapid identification of tumor cells and blood cells with silver film SERS substrate

The detection of circulating tumor cells (CTCs) from peripheral blood is considered as great significance for the diagnosis and prognosis of cancer patients. Raman spectroscopy is a highly sensitive optical detection technique that can provide fingerprint molecular identification information. In this paper, the silver film substrate surface-enhanced Raman scattering (SERS) was used to research several tumor cells, immortalized cells, clinical cancer cells isolated from cancer patient's tissue and blood cells. The results display that there is great difference for the nucleic acid characteristic peaks of those cells. The red blood cells have almost none nucleic acid characteristic peak and the SERS signals of white blood cells are only a slight increase. Except for immortalized cells and few tumor cells, the nucleic acid characteristic peaks of some tumor cells have huge enhancement. Nucleic acid characteristic peaks of clinical cancer cells also have greater enhancement. The discriminant model established by the intensity ratio of the nucleic acid characteristic peak 730 cm^-1 to the substrate background peak 900 cm^-1 shows that some tumor cells and clinical sample cells can be separated from white blood cells, but tumor cells with relatively low-DNA index cannot be differentiated from white blood cells. This study demonstrates that thin-film SERS technology can distinguish between blood cells and some types of tumor cells. This study opens up a new possible method for the detection of CTCs with label-free SERS spectra.

Dynamic Monitoring and Predictive Value of Circulating Tumor Cells in EGFR-Mutated Advanced Non-Small-Cell Lung Cancer Patients Treated With First-Line EGFR Tyrosine Kinase Inhibitors

BACKGROUND

There is an urgent need to develop a convenient and less invasive technique to monitor the efficacy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in patients with EGFR-mutated non-small-cell lung cancer (NSCLC). We proposed folate receptor-based assay to count circulating tumor cells (CTCs) to predict and dynamically monitor the therapeutic response to first-line EGFR-TKIs in patients with EGFR-mutated NSCLC.

PATIENTS AND METHODS

Eligible patients were enrolled, and 3 mL of blood was obtained before initial treatment, 1 month after treatment, and every 2 months thereafter. CTCs were isolated on the basis of negative enrichment by immunomagnetic beads and detected by a ligand-targeted PCR method.

RESULTS

A total of 232 patients with EGFR-mutated NSCLC and treated with first-line EGFR-TKIs were included. Patients with low baseline CTC count had a markedly longer progression-free survival (hazard ratio = 0.48; P < .001) and overall survival (hazard ratio = 0.52; P = .002) than those with high count. This difference remained significant in multivariate analysis. Dynamic change of CTC count was significantly associated with partial response (P = .042) and stable disease/progressive disease (P = .032). Notably, dynamic monitoring of CTC provided evidence of resistance to EGFR-TKIs before computed tomographic scanning with a median lead time of 113 days (range, 45-169 days).

CONCLUSION

The current evidence suggests that folate receptor-positive CTC counts can be used for both the dynamic monitoring and prediction of outcome in EGFR-mutated NSCLC patients treated with EGFR-TKIs, which could serve as an alternative or supplement to computed tomographic scanning.

Epithelial‑mesenchymal transition phenotype of circulating tumor cells is associated with distant metastasis in patients with NSCLC

Circulating tumor cells (CTCs) are closely associated with cancer metastasis in preclinical models and patients with cancer. However, to the best of the authors knowledge, it remains unknown which type of CTCs may serve the key role in cancer metastasis. The present study investigated the association between the epithelial‑mesenchymal transition (EMT) phenotype of CTCs from the peripheral blood and distant metastasis in patients with non‑small cell lung cancer (NSCLC). Expression of EMT markers in CTCs from a cohort of patients was detected using Canpatrol™ CTC assays. A total of 110 patients (85 patients with NSCLC and 25 patients with benign diseases) were recruited. Among the 110 patients, 88 (80.0%) were characterized as CTC positive with EMT markers. Receiver operating characteristic curves revealed that E+/M+ CTCs exhibited the highest area under the curve (AUC) value of 0.876 [95% confidence interval (CI), 0.805‑0.948; P<0.001) in distinguishing between patients with NSCLC and benign pulmonary diseases, and M+ CTCs had the highest AUC value of 0.723 (95% CI, 0.612‑0.833; P<0.001) in differentiating patients with NSCLC with distant metastasis from those with non‑distant metastasis. The results indicate the potential predictive value of distant metastasis of the EMT phenotype of CTCs in the peripheral blood of patients with NSCLC.

Predictive and prognostic value of folate receptor-positive circulating tumor cells in small cell lung cancer patients treated with first-line chemotherapy

To assess the predictive and prognostic significance of folate receptor (FR)-positive circulating tumor cells (CTCs) in patients with small cell lung cancer (SCLC) received first-line chemotherapy. Eligible patients with chemotherapy-naïve, unresectable SCLC were enrolled and blood samples were collected. CTCs were enumerated using ligand-targeted polymerase chain reaction (LT-PCR) at baseline, after two cycles of chemotherapy regimen and on disease progression. In total, 80 patients were enrolled and 67 (83.8%) had positive CTC count at baseline (CTCs ≥ 8.7 FU/3mL). The baseline CTC counts in patients with partial response (PR) were significantly higher than those with progression disease (PD) (P = 0.0365). An obvious reduction of CTC enumeration after two cycles of chemotherapy was significantly correlated with PR (P = 0.0380), instead of SD (P = 0.4934). Among positive CTC count group, patients with relative low CTC level had significantly longer progression-free survival (PFS) and overall survival (OS) than those with high CTC level (PFS: 9.1 vs 6.9 months, P = 0.0458; OS: 11.1 vs 8.6 months, P = 0.056). In multivariate analysis, distant metastases (HR = 1.466, P = 0.021) and relative low CTC level (HR = 0.656, P = 0.049) were the independent predictive factors for patients with SCLC received first-line chemotherapy. The present results demonstrated that baseline CTC counts could be the valuable predictive and prognostic biomarker for patients with SCLC received first-line chemotherapy. The reduction of CTC enumeration after two cycles of chemotherapy was a potential predictor of chemotherapeutic response in SCLC.

Performance evaluation of detecting circulating tumor cells and tumor cells in bronchoalveolar lavage fluid in diagnosis of peripheral lung cancer

Background

To evaluate the diagnostic performances of detecting circulating tumor cells (CTCs) and tumor cells in bronchoalveolar lavage fluid (BALF) for peripheral lung cancer.

Methods

A total of 247 patients with lung cancer and 70 cases with benign lung disease were recruited in this study. Peripheral blood and BALF samples were collected, in which the tumor cells were enriched by negative immunomagnetic selection and detected by fluorescence in situ hybridization (FISH) of chromosome enumeration probe 8 (CEP8). The levels of tumor-associated markers (e.g., CEA, CA125, and NSE) in peripheral blood plasma were measured by using electrochemiluminescence.

Results

The numbers of CTCs detected in peripheral blood were significantly higher in patients with lung cancer than those with benign lung disease (5.78±0.57 vs. 1.13±0.39, Z=-8.64, P<0.01). Similarly, tumor cells count in BALF of malignancy were higher than that of benign lesions (6.76±0.89 vs. 0.89±0.23, Z=-6.254, P<0.01). However, as for patients with lung cancer and benign lung disease, the numbers of tumor cells in peripheral blood were comparable with those in BALF (both P>0.05). Detecting CTCs and tumor cells in BALF had similar areas under curves (AUC =0.871 and 0.963, respectively; P>0.05) in discriminating benign lesions from lung cancer (sensitivity 83.8% and 92.6%, specificity 86.5% and 99.9%, respectively), both of which were larger than those of NSE, CEA, and CA125 (AUC =0.564, 0.512 and 0.554, respectively; all P<0.05). The diagnostic performances of discriminating benign lesions and lung cancer in BALF and peripheral blood were both in concordance with that of histopathology (kappa values 0.662 and 0.569, respectively; both P<0.001).

Conclusions

Detecting tumor cells in peripheral blood and BALF may sensitive to identify benign and malignant peripheral lung lesions and be of value for early diagnosis of lung cancer.

Liquid biopsy for early stage lung cancer

Liquid biopsy, which analyzes biological fluids especially blood specimen to detect and quantify circulating cancer biomarkers, have been rapidly introduced and represents a promising potency in clinical practice of lung cancer diagnosis and prognosis. Unlike conventional tissue biopsy, liquid biopsy is non-invasive, safe, simple in procedure, and is not influenced by manipulators' skills. Notably, some circulating cancer biomarkers are already detectable in disease with low-burden, making liquid biopsy feasible in detecting early stage lung cancer. In this review, we described a landscape of different liquid biopsy methods by highlighting the rationale and advantages, accessing the value of various circulating biomarkers and discussing their possible future development in the detection of early lung cancer.

Combined use of EpCAM and FRα enables the high-efficiency capture of circulating tumor cells in non-small cell lung cancer

Circulating tumor cells (CTCs) provide a new approach for auxiliary diagnosis, therapeutic effect evaluation, and prognosis prediction for cancer patients. The epithelial cell adhesion molecule (EpCAM)-based separation method (CellSearch) showed good clinical use in multiple types of cancer. Nevertheless, some non-small cell lung cancer (NSCLC) tumor cells have a lower expression of EpCAM and are less frequently detected by CellSearch. Here, we present a highly sensitive immunomagnetic separation method to capture CTCs based on two cell surface markers for NSCLC, EpCAM and Folate receptor alpha (FRα). Our method has been demonstrated to be more efficient in capturing NSCLC cells (P < 0.01) by enriching three types of CTCs: EpCAM⁺/FRα^-/low, EpCAM^-/low/FRα⁺, and EPCAM⁺/FRα⁺. In 41 NSCLC patients, a significantly higher CTC capture rate (48.78% vs. 73.17%) was obtained, and by using a cutoff value of 0 CTC per 2 ml of blood, the sensitivities were 53.66% and 75.61% and the specificities were 100% and 90% for anti-EpCAM-MNs or a combination of anti-EpCAM-MNs and anti-FRα-MNs, respectively. Compared with the tumor-specific LT-PCR based on FRα, our method can isolate intact FRα⁺ CTCs, and it is advantageous for additional CTC-related downstream analysis. Our results provide a new method to increase the CTC capture efficiency of NSCLC.

Molecular characterization of circulating tumor cells in lung cancer: moving beyond enumeration

Molecular characterization of tumor cells is a key step in the diagnosis and optimal treatment of lung cancer. However, analysis of tumor samples, often corresponding to small biopsies, can be difficult and does not accurately reflect tumor heterogeneity. Recent studies have shown that isolation of circulating tumor cells (CTCs) is feasible in non-small cell lung cancer patients, even at early disease stages. The amount of CTCs corresponds to the metastatic potential of the tumor and to patient prognosis. Moreover, molecular analyses, even at the single-cell level, can be performed on CTCs. This review describes the technologies currently available for detecting and capturing CTCs, the potential for downstream molecular diagnostics, and the clinical applications of CTCs isolated from lung cancer patients as screening, prognostic, and predictive tools. Main limitations of CTCs are also discussed.

Mesenchymal phenotype of circulating tumor cells is associated with distant metastasis in breast cancer patients

In this study, we investigated the relationship between the epithelial–mesenchymal transition phenotype of circulating tumor cells (CTCs) and distant metastasis in breast cancer patients. We analyzed the expression of epithelial (epithelial cell adhesion molecule, cytokeratin [CK]8, CK18 and CK19) and mesenchymal (vimentin and TWIST1) markers in CTCs from a large cohort of Chinese breast cancer patients (N=1083) using Canpatrol™ CTC assays. We identified CTCs in 84.9% (920/1083) of the breast cancer patients enrolled in this study. Among these 920 patients, 547 showed epithelial CTCs, 793 showed biphenotypic CTCs and 516 showed mesenchymal CTCs. Receiver operating characteristic (ROC) curves demonstrated circulation of both biphenotypic and mesenchymal CTCs (area under ROC curve value: 0.728; sensitivity: 68.7% and specificity: 71.6%) in patients was associated with distant metastasis. These findings demonstrate that the epithelial–mesenchymal transition phenotype of CTCs is a potential biomarker predictive of distant metastasis in breast cancer.

Liquid biopsy in non-small cell lung cancer: a key role in the future of personalized medicine?

INTRODUCTION

Liquid biopsies, especially the analysis of circulating tumor DNA (ctDNA), as a novel and non-invasive method for the diagnosis and monitoring of non-small cell lung cancer (NSCLC) have already been implemented in clinical settings. The majority of ctDNA is released from apoptotic or necrotic tumor cells, thus reflecting the genetic profile of a tumor. Numerous studies have reported a high concordance in mutation profiles derived from liquid biopsy and tissue biopsy, especially in driver genes. Liquid biopsy could overcome the clonal heterogeneity of tumour biopsy, as it provides a single snapshot of a tumour tissue. Moreover, non-invasiveness is the biggest advantage for liquid biopsy, and the procedure can be repeatedly performed during the treatment for the purpose of monitoring. Therefore, ctDNA could act as a potential complementary method for tissue biopsies in diagnosis, prognostic, treatment response and resistance. Areas covered: This review summarizes the recent advancements in liquid biopsy with a focus on NSCLC, including its applications and technologies associated with assessing ctDNA. The authors conclude the review by discussing the challenges associated with liquid biopsy. Expert commentary: The analysis of ctDNA represents a promising method for liquid biopsy, which will be a novel and potentially complementary method in diagnosis, treatment and prognostic in NSCLC at all stages.

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.

Circulating Tumor Cells as Cancer Biomarkers in the Clinic

It is believed that the development of metastatic cancer requires the presence of circulating tumor cells (CTCs) , which are found in a patient's circulation as rare abnormal cells comingled with billions of the normal red and white blood cells. The systems developed for detection of CTCs have brought progress to cancer treatment. The molecular characterization of CTCs can aid in the development of new drugs, and their presence during treatment can help clinicians determine the prognosis of the patient. Studies have been carried out in patients early in the disease course, with only primary tumors, and the role of CTCs in prognosis seems to be as important as it is in patients with metastatic disease. The published studies on CTCs have focused on their prognostic significance, their utility in real-time monitoring of therapies, the identification of therapeutic and resistance targets, and understanding the process of metastasis . The analysis of CTCs during the early stages, as a "liquid biopsy," helps to monitor patients at different points in the disease course, including minimal residual disease, providing valuable information about the very early assessment of treatment effectiveness. Finally, CTCs can be used to screen patients with family histories of cancer or with diseases that can lead to the development of cancer. With standard protocols, this easily obtained and practical tool can be used to prevent the growth and spread of cancer. In this chapter, we review some important aspects of CTCs , surveying the disease aspects where these cells have been investigated.

[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。

Early detection of lung cancer by using an autoantibody panel in Chinese population

We have previously identified a panel of autoantibodies (AABs), including p53, GAGE7, PGP9.5, CAGE, MAGEA1, SOX2 and GBU4-5, that was helpful in the early diagnosis of lung cancer. This large-scale, multicenter study was undertaken to validate the clinical value of this 7-AABs panel for early detection of lung cancer in a Chinese population. Two independent sets of plasma samples from 2308 participants were available for the assay of AABs (training set = 300; validation set = 2008). The concentrations of AABs were quantitated by enzyme-linked immunosorbent assay (ELISA), and the optimal cutoff value for each AAB was determined in the training set and then applied in the validation set. The value of the 7-AABs panel for the early detection of lung cancer was assessed in 540 patients who presented with ground-glass nodules (GGNs) and/or solid nodules. In the validation set, the sensitivity and specificity of the 7-AABs panel were 61% and 90%, respectively. For stage I and stage II non-small cell lung cancer (NSCLC), the sensitivity of the 7-AABs panel was 62% and 59%, respectively, and for limited stage small cell lung cancer (SCLC) it was 59%; these sensitivity values were considerably higher than for traditional biomarkers (including CEA, NSE and CYFRA21-1). Importantly, the combination of the 7-AABs panel and low-dose computed tomography (CT) scanning significantly improved the diagnostic yield in patients presenting with GGNs and/or solid nodules. In conclusion, our 7-AABs panel has clinical value for early detection of lung cancer, including early-stage lung cancer presenting as GGNs.

Biology and clinical significance of circulating tumor cell subpopulations in lung cancer

By identifying and tracking genetic changes in primary tumors and metastases, patients can be stratified for the most efficient therapeutic regimen by screening for known biomarkers. However, retrieving tissues biopsies is not always feasible due to tumor location or risk to patient. Therefore, a liquid biopsies approach offers an appealing solution to an otherwise invasive procedure. The rapid growth of the liquid biopsy field has been aided by improvements in the sensitivity and specificity of enrichment assays for isolating circulating tumor cells (CTCs) from normal surrounding blood cells. Furthermore, the identification and molecular characterization of CTCs has been shown in numerous studies to be of diagnostic and prognostic relevance in breast, prostate and colon cancer patients. Despite these advancements, and the highly metastatic nature of lung cancer, it remains a challenge to detect CTCs in advanced non-small cell lung cancer (NSCLC). It may be that loss of epithelial features, in favor of a mesenchymal phenotype, and the highly heterogeneous nature of NSCLC CTCs contribute to their evasion from current detection methods. By identifying a broader spectrum of biomarkers that could better differentiate the various NSCLC CTCs subpopulations, it may be possible to not only improve detection rates but also to shed light on which CTC clones are likely to drive metastatic initiation. Here we review the biology of CTCs and describe a number of proteins and genetic targets which could potentially be utilized for the dissemination of heterogenic subpopulations of CTCs in NSCLC.

Circulating tumor cells in early stage lung adenocarcinoma: a case series report and literature review

PURPOSE

The study aimed to monitor circulating tumor cells (CTCs) in early stage lung adenocarcinoma patients.

RESULTS

CTCs were characterized and classified to epithelial (E-) CTCs, mesenchymal (M-) CTCs and epithelial- mesenchymal (E&M-) CTCs, as per epithelial-mesenchymal transition(EMT) biomarkers. CTCs could not be found in healthy controls. However, in cohort A, CTCs were found in 17 (17/18) cases. Detection rate of E-CTCs was lower (5/18) compared with M-CTC (10/18) or E&M-CTC (14/18). Highly abundant M-CTCs were prone to being in the tumors > 2 cm. In cohorts A and B, CTCs count increased significantly in all patients with tumor progression (7/7). Higher CTCs level or change range could be found postoperatively in the patients with tumor progression, as compared with patients with disease free survival (P < 0.01). Additionally, CTCs detected by CanPatrolTM could be validated by CytoploRare or Pep@MNPs.

MATERIALS AND METHODS

We included four cohorts of patients and 20 healthy controls. In cohort A, CTCs were detected by a newly established approach, i.e., CanPatrolTM, prior to anesthesia and monitored after operation longitudinally. In cohort B, CTCs were not assessed prior to operation, but were longitudinally detected after operation. For validation, we detected FOLR(+)-CTCs by using CytoploRare and EPCAM(+)-CTCs by using Pep@MNPs prior to operation, in cohorts C and D, respectively.

CONCLUSION

CTCs can be detected in early stage lung adenocarcinoma, even in adenocarcinoma in situ, and CTCs detection can effectively monitor tumor progression. The distinguishing of biomarkers of highly invasive and aggressive CTCs warrants further robust study.

[Diagnostic Value of Folate Receptor-positive Circulating Tumor Cell in Lung Cancer: A Pilot Study]

背景与目的

评价一种通过叶酸受体(folate receptor, FR)检测循环肿瘤细胞(circulating tumor cell, CTC)的方法用于肺癌临床诊断的实用性和可行性及进一步探究CTC在肺癌术后复发的预测价值。

方法

通过免疫磁珠负向富集方法从3 mL外周血中捕获循环肿瘤细胞，再用肿瘤特异性叶酸配体-寡核苷酸偶和物标记捕获的循环肿瘤细胞，洗去没有结合的偶和物后，洗脱下特异性结合的偶合物的寡核苷酸用于定量PCR扩增分析。

结果

97例肺癌患者的CTC水平高于肺部良性疾病患者(P < 0.001)。本检测方法以8.7 Folate Units/3 mL为cutoff值，结果显示靶向PCR法对肺癌的检测灵敏度为82.5%，特异性为72.2%，特别是在Ⅰ期肺癌灵敏度达到86.8%。与其他肿瘤标志物(NSE、CEA、CYFRA21-1)比较，CTC对肺癌及Ⅰ期肺癌具有较高的诊断准确性(0.859; 95%CI: 0.779-0.939)和(0.912; 95%CI: 0.829-0.994)。5例肺癌患者术后2周内CTC水平高于cutoff值。

结论

叶酸受体阳性循环肿瘤细胞可以应用于肺癌的临床诊断，即使是对早期非小细胞肺癌(non-small cell lung cancer, NSCLC)的诊断。

[Present Situation of Lung Cancer Screening Methods]

肺癌是目前恶性肿瘤死亡的首要原因，早期诊断对肺癌的预后至关重要。研究显示低剂量计算机断层扫描（computed tomography, CT）筛查可以使肺癌的死亡率下降。但其存在的问题不可忽视，如过高的假阳性率、过度诊断、辐射效应等。作为一种肿瘤无创筛查方法，血液相关肿瘤标志物的检测，在肺癌早期诊断中显示出良好的敏感性和特异性。如何利用现有的筛查手段，建立肺癌筛查综合模式，需要更多大规模的临床研究。

Circulating Tumor Cell and Cell-free Circulating Tumor DNA in Lung Cancer

Circulating tumor cells (CTCs) are tumor cells that are separated from the primary site or metastatic lesion and disseminate in blood circulation. CTCs are considered to be part of the long process of cancer metastasis. As a 'liquid biopsy', CTC molecular examination and investigation of single cancer cells create an important opportunity for providing an understanding of cancer biology and the process of metastasis. In the last decade, we have seen dramatic development in defining the role of CTCs in lung cancer in terms of diagnosis, genomic alteration determination, treatment response and, finally, prognosis prediction. The aims of this review are to understand the basic biology and to review methods of detection of CTCs that apply to the various types of solid tumor. Furthermore, we explored clinical applications, including treatment monitoring to anticipate therapy resistance as well as biomarker analysis, in the context of lung cancer. We also explored the potential use of cell-free circulating tumor DNA (ctDNA) in the genomic alteration analysis of lung cancer.

Circulating long noncoding RNA GAS5 is a novel biomarker for the diagnosis of nonsmall cell lung cancer

The recently discovered long noncoding RNAs have the potential to regulate many biological processes, which are aberrantly expressed in many tumor types. Our previous study showed that the long noncoding RNA-growth arrest-specific transcript 5 (GAS5) was decreased in lung cancer tissue, which contributed to the proliferation and apoptosis of nonsmall cell lung cancer (NSCLC). GAS5 was also associated with the prognosis of lung cancer patients. These results suggest that GAS5 may represent a novel prognostic indicator and a target for gene therapy in NSCLC. However, the expression and diagnosis significance of GAS5 in the plasma of NSCLC patients was unknown. The plasma samples were more readily available than the tissue samples in clinical, so we designed the study to investigate the diagnosis value of GAS5 in blood samples. In our study, 90 patients with NSCLC and 33 healthy controls were included. Blood samples were collected before surgery and therapy. We extracted the free RNA in the plasma and analyzed the expression of GAS5 with quantitative reverse transcription PCR. Suitable statistics methods were used to compare the plasma GAS5 levels of preoperative and postoperative plasma samples between the NSCLC patients and healthy controls. Receiver-operating characteristic curve analysis was used to evaluate the diagnostic sensitivity and specificity of plasma GAS5 in NSCLC. The results showed that GAS5 was detectable and stable in the plasma of NSCLC patients. Furthermore, the plasma levels of GAS5 were significantly down-regulated in NSCLC patients compared with healthy controls (P = 0.000). Moreover, GAS5 levels increased markedly on the seventh day after surgery compared with preoperative GAS5 levels in NSCLC patients (P = 0.003). GAS5 expression levels could be used to distinguish NSCLC patients from control patients with an area under the curve of 0.832 (P < 0.0001; sensitivity, 82.2%; specificity, 72.7%). The combination of the GAS5 and carcinoembryonic antigen could produce an area of 0.909 under the receiver-operating characteristic curve in distinguishing NSCLC patients from control subjects (95% confidence interval 0.857-0.962, P = 0.000). We have demonstrated that GAS5 expression was decreased in NSCLC Plasma. Plasma samples were more accessible than tissue samples in clinical; therefore, GAS5 could be an ideal biomarker for the diagnosis of NSCLC.

The diagnostic value of circulating cell free DNA quantification in non-small cell lung cancer: A systematic review with meta-analysis

OBJECTIVES

The aim of the current study was to assess the diagnostic value of circulating cell free DNA (cfDNA) quantification in discriminating non-small cell lung cancer (NSCLC) from healthy individuals.

MATERIALS AND METHODS

An electronic search was conducted on PubMed, EMBASE, Web of Science, and Cochrane Library. Eligible studies regarding to examine the diagnostic value of cfDNA in the detection of NSCLC were extracted and analyzed.

RESULTS

We identified 15 eligible studies with a total of 2125 patients. The pooled results for quantification of cfDNA in lung cancer screening in the included studies were as follows: sensitivity, 81% (95% confidence interval (CI), 76%-84%); specificity, 85% (95% CI, 77%-91%); diagnostic odds ratio, 23.87 (95% CI, 13.37-42.61); and areas under the summary receiver operating characteristic curves were 0.89 (95% CI, 0.86-0.92). Subgroup analyses according to the time of sample collection, sample materials, test method, reference gene and cutoff value did not improve sensitivity, but specificity could be significantly improved when we only included the studies using cfDNA sample before surgery or antitumor treatment and real-time PCR to detect cfDNA and human β-actin as a reference gene.

CONCLUSION

Quantification of cfDNA was a promising and effective biomarker for discriminating NSCLC from healthy individuals.

[Blood-based Tumor Markers in Lung Cancer]

In recent years, "liquid biopsy" received enormous attention as a new detecting method. As a non-invasive tumor screening method, the applications of liquid biopsy include early detection, monitoring relapse, assessment of therapy and molecule expression in lung cancer. The main source of liquid biopsy comes from circulating tumor cells (CTCs), ctDNA, and so on. This review will explore the biological characteristics, detection technologies and clinical applications of CTCs, ctDNA and other tumor markers in lung cancer and summarize liquid biopsy which in accord with three important criteria of high sensitivity (high specificity), clinical utility and repeatability, especially a new method of ligand-targeted PCR (LT-PCR) that showed a high sensitivity of 67.2% in stage I lung cancer. We expect that "liquid biopsy" could be really explored from scientific research to clinical application.

The potential diagnostic power of circulating tumor cell analysis for non-small-cell lung cancer

In non-small-cell lung cancer (NSCLC), genotyping tumor biopsies for targetable somatic alterations has become routine practice. However, serial biopsies have limitations: they may be technically difficult or impossible and could incur serious risks to patients. Circulating tumor cells (CTCs) offer an alternative source for tumor analysis that is easily accessible and presents the potential to identify predictive biomarkers to tailor therapies on a personalized basis. Examined here is our current knowledge of CTC detection and characterization in NSCLC and their potential role in EGFR-mutant, ALK-rearranged and ROS1-rearranged patients. This is followed by discussion of the ongoing issues such as the question of CTC partnership as diagnostic tools in NSCLC.