Circulating tumor cells in pulmonary venous blood of primary lung cancer patients

The circulation stage of the metastatic cascade: A mathematical description and its clinical implications

Metastatic cascade is a multi-stage process that starts with separation of a cancer cell from the primary tumor and ends with the emergence of a detectable metastasis. In the process the initiator cancer cell enters the circulatory system (intravasates), flows with the blood, and exits the circulation (extravasates) into an organ or tissue. The time period between intravasation and extravasation constitutes the circulation stage of the metastatic cascade. This stage is unique in that it lends itself naturally to various non-invasive observations and measurements in an individual cancer patient. This creates an opportunity for gaining insight into metastasis, its mathematical modeling, and designing diagnostic/prognostic tools and new cancer therapies. Although mechanisms of intravasation, survival and extravasation of circulating tumor cells (CTCs) are very complex and largely unknown, mathematical modeling of the circulation stage of the metastatic cascade is facilitated by two inter-related factors: a relative simplicity of the circulatory network and the cyclic nature of blood flow. The article presents a single-subject stochastic model of CTC dynamics that leads to simple formulas, applicable to any homogeneous CTC population, for organ-specific extravasation probabilities, the distribution and expected value of the number, X, of circulation cycles completed by a CTC prior to extravasation, and the average circulation time. In particular, we found that the distribution of random variable X is geometric G(x), where parameter x is measurable, at least in principle, in an individual subject. We also discuss implications of our results for cancer research and treatment.

Different Liquid Biopsies for the Management of Non-Small Cell Lung Cancer in the Mutational Oncology Era

In the last ten years, liquid biopsy has been slowly joining the traditional invasive techniques for the diagnosis and monitoring of tumors. Liquid biopsies allow easy repeated sampling of blood, reflect the tumor scenario, and make personalized therapy real for the patient. Liquid biopsies isolate and utilize different substrates present in patients' body fluids such as circulating tumor cells, circulating tumor DNA, tumor extracellular vesicles, etc. One of the most-used solid cancers in the development of the non-invasive liquid biopsy approach that has benefited from scientific advances is non-small cell lung cancer (NSCLC). Using liquid biopsy, it is possible to have more details on NSCLC staging, progression, heterogeneity, gene mutations and clonal evolution, etc., basing the treatment on precision medicine as well as on the screening of markers for therapeutic resistance. With this review, the authors propose a complete and current overview of all different liquid biopsies available to date, to understand how much has been carried out and how much remains to be completed for a better characterization of NSCLC.

Circulating Tumor Cells as a Predictive Biomarker in Resectable Lung Cancer: A Systematic Review and Meta-Analysis

Background: In breast, prostate, and other epithelial tumors, circulating tumor cells (CTC) in peripheral blood may predict survival. Our study evaluated the prognostic significance of baseline and postoperative CTC in patients with early non-small cell lung cancer (NSCLC) through a meta-analytic approach. Methods: Prospective studies comparing survival outcomes between positive (CTC+) and negative CTC (CTC−) patients were systematically searched. Primary outcomes were overall (OS) and disease-free survival (DFS) with hazard ratio (HR) and 95% confidence interval (CI) as the effect measure. Pooled HR determined the prognostic role under a fixed-effect or random-effect model depending on heterogeneity. Results: Eighteen studies with 1321 patients were eligible. CTC+ patients were associated with an increased risk of death (HR 3.53, 95% CI 2.51−4.95; p < 0.00001) and relapse (HR 2.97, 95% CI 2.08−4.22; p < 0.00001). Subgroup analysis results were consistent in different subsets, including time points (baseline and postoperative) and sources (peripheral and pulmonary vein) of blood collection, detection methods (label-free, label-dependent, and RT-PCR), and follow-up duration. Conclusion: Our meta-analysis revealed that CTC is a promising predictive biomarker for stratifying survival outcomes in patients with early-stage NSCLC. However, future studies are required to validate these findings and standardize detection methods.

The actin cytoskeleton: Morphological changes in pre- and fully developed lung cancer

Actin, a primary component of the cell cytoskeleton can have multiple isoforms, each of which can have specific properties uniquely suited for their purpose. These monomers are then bound together to form polymeric filaments utilizing adenosine triphosphate hydrolysis as a source of energy. Proteins, such as Arp2/3, VASP, formin, profilin, and cofilin, serve important roles in the polymerization process. These filaments can further be linked to form stress fibers by proteins called actin-binding proteins, such as α-actinin, myosin, fascin, filamin, zyxin, and epsin. These stress fibers are responsible for mechanotransduction, maintaining cell shape, cell motility, and intracellular cargo transport. Cancer metastasis, specifically epithelial mesenchymal transition (EMT), which is one of the key steps of the process, is accompanied by the formation of thick stress fibers through the Rho-associated protein kinase, MAPK/ERK, and Wnt pathways. Recently, with the advent of "field cancerization," pre-malignant cells have also been demonstrated to possess stress fibers and related cytoskeletal features. Analytical methods ranging from western blot and RNA-sequencing to cryo-EM and fluorescent imaging have been employed to understand the structure and dynamics of actin and related proteins including polymerization/depolymerization. More recent methods involve quantifying properties of the actin cytoskeleton from fluorescent images and utilizing them to study biological processes, such as EMT. These image analysis approaches exploit the fact that filaments have a unique structure (curvilinear) compared to the noise or other artifacts to separate them. Line segments are extracted from these filament images that have assigned lengths and orientations. Coupling such methods with statistical analysis has resulted in development of a new reporter for EMT in lung cancer cells as well as their drug responses.

Characterization of the MicroRNA Cargo of Extracellular Vesicles Isolated from a Pulmonary Tumor-Draining Vein Identifies miR-203a-3p as a Relapse Biomarker for Resected Non-Small Cell Lung Cancer

In resected non-small cell lung cancer (NSCLC), post-surgical recurrence occurs in around 40% of patients, highlighting the necessity to identify relapse biomarkers. An analysis of the extracellular vesicle (EV) cargo from a pulmonary tumor-draining vein (TDV) can grant biomarker identification. We studied the pulmonary TDV EV-miRNAome to identify relapse biomarkers in a two-phase study (screening and validation). In the screening phase, a 17-miRNA relapse signature was identified in 18 selected patients by small RNAseq. The most expressed miRNA from the signature (EV-miR-203a-3p) was chosen for further validation. Pulmonary TDV EV-miR-203a-3p was studied by qRT-PCR in a validation cohort of 70 patients, where it was found to be upregulated in relapsed patients (p = 0.0194) and in patients with cancer spread to nearby lymph nodes (N+ patients) (p = 0.0396). The ROC curve analysis showed that TDV EV-miR-203a-3p was able to predict relapses with a sensitivity of 88% (AUC: 0.67; p = 0.022). Moreover, patients with high TDV EV-miR-203a-3p had a shorter time to relapse than patients with low levels (43.6 vs. 97.6 months; p = 0.00703). The multivariate analysis showed that EV-miR-203a-3p was an independent, predictive and prognostic post-surgical relapse biomarker. In conclusion, pulmonary TDV EV-miR-203a-3p is a promising new relapse biomarker for resected NSCLC patients.

Clinical Applications of Circulating Tumour Cells and Circulating Tumour DNA in Non-Small Cell Lung Cancer-An Update

Despite efforts to improve earlier diagnosis of non-small cell lung cancer (NSCLC), most patients present with advanced stage disease, which is often associated with poor survival outcomes with only 15% surviving for 5 years from their diagnosis. Tumour tissue biopsy is the current mainstream for cancer diagnosis and prognosis in many parts of the world. However, due to tumour heterogeneity and accessibility issues, liquid biopsy is emerging as a game changer for both cancer diagnosis and prognosis. Liquid biopsy is the analysis of tumour-derived biomarkers in body fluids, which has remarkable advantages over the use of traditional tumour biopsy. Circulating tumour cells (CTCs) and circulating tumour DNA (ctDNA) are two main derivatives of liquid biopsy. CTC enumeration and molecular analysis enable monitoring of cancer progression, recurrence, and treatment response earlier than traditional biopsy through a minimally invasive liquid biopsy approach. CTC-derived ex-vivo cultures are essential to understanding CTC biology and their role in metastasis, provide a means for personalized drug testing, and guide treatment selection. Just like CTCs, ctDNA provides opportunity for screening, monitoring, treatment evaluation, and disease surveillance. We present an updated review highlighting the prognostic and therapeutic significance of CTCs and ctDNA in NSCLC.

Levels of Extracellular Vesicles in Pulmonary and Peripheral Blood Correlate with Stages of Lung Cancer Patients

BACKGROUND

The extracellular vesicle (EV) concentration is known to be higher in cancer patients than in healthy individuals. Herein, we report that EV levels differ in the tumor-draining pulmonary vein blood and the peripheral blood of animal models and human subjects at different pathological stages of lung cancer.

METHODS

Ten rabbits and 40 humans formed the study cohorts. Blood was collected from the peripheral vein of members of all groups. Pulmonary blood was collected intraoperatively from all groups except for the healthy human controls. Quantitative analysis of EV levels was performed using a nanoparticle tracking assay, a CD63 enzyme-linked immunosorbent assay, and western blotting.

RESULTS

The EV levels in the peripheral blood of animals and patients with lung cancer were higher than those in the peripheral blood of healthy controls (p < 0.01 and p < 0.001, respectively). Moreover, for both animals and patients with lung cancer, the EV levels in the pulmonary blood were significantly higher than those in the preoperative peripheral blood (p < 0.01 and p < 0.0001, respectively). In patients, the pathological stages of lung cancer showed a higher correlation with the pulmonary EV levels than the peripheral EV levels.

CONCLUSIONS

EV levels increased with increasing lung cancer grade, and this trend was more prominent in the pulmonary blood than in the peripheral blood.

Possible role of circulating tumor cells in early detection of lung cancer

The prognosis of lung cancer varies highly depending on the disease stage at diagnosis, from a 5-year survival rate close to 90% in stage I, to 10% or less in stage IV disease. The enhancement of early diagnosis of this malignancy is mandatory to improve prognosis, because lung cancer patients stay long asymptomatic or few symptomatic after disease onset. Nowadays, liquid biopsy has emerged as a minimally-invasive tool to address the urgent need for real time monitoring, stratification, and personalized treatment of malignancies, including lung cancer. Liquid biopsy refers to a class of biomarkers, including circulating tumor cells (CTCs), cell-free circulating tumor DNA (ctDNA) and tumor-derived extracellular vesicles (tdEV). Since CTCs represent a crucial step in disease progression and metastasis, we reviewed here the scientific literature about the use of CTCs in early diagnosis of lung cancer; different techniques, and different strategies (e.g., source of analysis sample or high-risk groups of patients) were discussed showing the potential of implementing liquid biopsy in the clinical routine of non-metastatic lung cancer.

Multiple functions of microfluidic platforms: Characterization and applications in tissue engineering and diagnosis of cancer

Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems.

Circulating Tumor Cells as a Tool of Minimal Residual Disease Can Predict Lung Cancer Recurrence: A longitudinal, Prospective Trial

Background: The role of circulating tumor cells (CTCs) for predicting the recurrence of cancer in lung cancer patients after surgery remains unclear. Methods: A negatively selected protocol of CTC identification was applied. For all the enrolled patients, CTC testing was performed before and after surgery on the operation day (day 0), postoperative day 1, and day 3. The daily decline and trend of CTCs were analyzed to correlate with cancer relapse. The mixed model repeated measures (MMRM) adjusted by cancer characteristics was applied for statistical significance. Results: Fifty patients with lung mass undergoing surgery were enrolled. Among 41 primary lung cancers, 26 (63.4%) were pathological stage Tis and I. A total of 200 CTC tests were performed. MMRM analysis indicated that surgery could contribute to a CTC decline after surgery in all patients with statistical significance (p = 0.0005). The daily decrease of CTCs was statistically different between patients with and without recurrence (p = 0.0068). An early rebound of CTC counts on postoperative days 1 and 3 was associated with recurrence months later. Conclusion: CTC testing can potentially serve as a tool for minimal residual disease detection in early-staged lung cancer after curative surgery.

Detection of circulating tumor cells in patients with lung cancer using metallic micro-cavity array filter: A pilot study

We have developed a metallic micro-cavity array filter and an automated detection system for capturing circulating tumor cells (CTCs). In this single institutional pilot study, we assessed the ability of this device to detect CTCs in patients with lung cancer at each stage. Patients diagnosed with lung cancer, undergoing planned surgery for lung cancer, or suspected of having lung cancer were recruited (40 recruited and 2 excluded). Blood samples were obtained from the patients and 3 ml whole blood was applied to the device without any preparation. The captured cells were stained to differentiate the nucleus, and determine cytokeratin and CD45 expression. Subsequently, two operators blinded to clinical information counted the number of CTCs. Sample collection was performed at the time of recruitment, before treatment and ~3 months after initial blood collection. CTC counts at recruitment were 1.4±0.4, 1.8±1.2, 1.3±0.6 and 7.4±5.1 (mean ± SE) in clinical stages I, II, III and IV, respectively. No significant difference was observed among the stages. These data indicated the ability of this device to detect CTCs at early or non-metastatic stages of lung cancer. Further research on a larger scale is needed for a more accurate assessment of the device, and research on the utility of captured cells remains a future challenge.

Circulating tumor cells detection in tumor draining vein of breast cancer patients

Circulating tumor cells (CTCs) in tumor draining vein blood (DB) are potential sources for liquid biopsy. However, the identification of CTCs in DB of breast cancer has not been attempted. In this study, we investigated the feasibility of CTC detection in DB of breast cancer patients using a newly developed filtration-based microfluidic CTC detection device. Samples of peripheral vein blood (PB) and DB drawn from the lateral thoracic vein of the resected breast tissue were collected during the perioperative period. We investigated 41 breast cancer patients who underwent breast surgery with axillary lymph node dissection. DB was successfully collected in 36 patients (87.8%), with a mean amount of 0.85 ml. CTCs were detected in 58.3% of PB samples and 80.6% of DB samples. DB had significant higher number of CTCs compared with PB (p < 0.001). CTCs were detected in 75.0% of DB samples and 50.0% of PB samples from patients achieving pathological complete response after neoadjuvant chemotherapy. These results suggest that abundant CTCs are released into the DB of breast cancer patients, indicating that CTCs in DB would be alternative sources for liquid biopsy and potential indicators for monitoring of treatment response and prognosis in breast cancer patients.

Analysis of Released Circulating Tumor Cells During Surgery for Non-Small Cell Lung Cancer

PURPOSE

Tumor cells from patients with lung cancer are expelled from the primary tumor into the blood, but difficult to detect in the peripheral circulation. We studied the release of circulating tumor cells (CTCs) during surgery to test the hypothesis that CTC counts are influenced by hemodynamic changes (caused by surgical approach) and manipulation.

EXPERIMENTAL DESIGN

Patients undergoing video-assisted thoracic surgery (VATS) or open surgery for (suspected) primary lung cancer were included. Blood samples were taken before surgery (T0) from the radial artery (RA), from both the RA and pulmonary vein (PV) when the PV was located (T1) and when either the pulmonary artery (T2 open) or the PV (T2 VATS) was dissected. The CTCs were enumerated using the CellSearch system. Single-cell whole-genome sequencing was performed on isolated CTCs for aneuploidy.

RESULTS

CTCs were detected in 58 of 138 samples (42%) of 31 patients. CTCs were more often detected in the PV (70%) compared with the RA (22%, P < 0.01) and in higher counts (P < 0.01). After surgery, the RA but not the PV showed less often CTCs (P = 0.02). Type of surgery did not influence CTC release. Only six of 496 isolated CTCs showed aneuploidy, despite matched primary tumor tissue being aneuploid. Euploid so-called CTCs had a different morphology than aneuploid.

CONCLUSIONS

CTCs defined by CellSearch were identified more often and in higher numbers in the PV compared with the RA, suggesting central clearance. The majority of cells in the PV were normal epithelial cells and outnumbered CTCs. Release of CTCs was not influenced by surgical approach.

Detection of Circulating Tumor Cell Molecular Subtype in Pulmonary Vein Predicting Prognosis of Stage I-III Non-small Cell Lung Cancer Patients

Background: There was rare studies on prognosis of pulmonary venous CTC and early or advanced NSCLC patients. We want to investigate whether CTCs and the subtype of it can predict the prognosis of NSCLC patients.

Patients and Methods: One hundred and fourteen patients with stage I-III NSCLC were included CanPatrol™ CTC analysis. PD-L1 expression level were detected in CTC of pulmonary vein. PD-L1, number of CTC in pulmonary, CTC's subtype, clinical characteristics, prognosis of patients were analyzed.

Results: 110/114 (96.5%) patients could be found CTCs in pulmonary vein, 58/114 (50.9%) patients had CTC≥15/ml in pulmonary vein, 53/110 patients (48.2%) were defined as having MCTC subtype and 56/110 patient were found have PD-L1 (+) CTC in pulmonary vein. Multivariate analyses showed that PVCTC, MCTC, and stage were independent factors of DFS (P < 0.05). No OS difference was found between number of CTC (P = 0.33) and other CTC factors (P > 0.05), only stage was independent factor of OS (P = 0.019). There were decreases of CTC number and MCTC number in EGFR mutant subgroup (P = 0.0009 and P = 0.007). There were increases of CTC (P = 0.0217), MCTC (P = 0.0041), and PD-L1 (+) CTC (P = 0.0002) number in KRAS mutant subgroup. There was increase of MCTC (P =0.0323) number in BRAF mutant. There were fewer CTCs in pulmonary vein for patients with EGFR mutant than in patients with full wild-type gene (P = 0.0346). There were more PD-L1 positive CTCs in pulmonary vein for patients with ALK rearrangement, KRAS mutant, BRAF mutant, or ROS1 mutant than in patients with full wild-type gene (P = 0.0610, P = 0.0003, P = 0.032, and P = 0.0237). There were more mesenchymal CTCs in pulmonary vein for patients with KRAS mutant and BRAF mutant than in patients with full wild-type gene (P = 0.073 and P = 0.0381). There were fewer mesenchymal CTCs in pulmonary vein for patients with EGFR mutant than in patients with full wild-type gene (P = 0.0898).

Conclusions: The patients with high number of CTCs, MCTCs, or PD-L1 (+) CTCs in pulmonary vein experienced poor prognosis of DFS. There are obvious correlations between the CTC subtype of NSCLC and the gene subgroups of tumor tissue.

Circulating tumor cells in pulmonary vein and peripheral arterial provide a metric for PD-L1 diagnosis and prognosis of patients with non-small cell lung cancer

Background

Lung cancer is the leading cause of death caused by malignant tumors. PD-L1(programmed cell death protein-1) has shown tremendous achievement in treating NSCLC. We sought to find the relationship between CTCs in the pulmonary vein and postoperative PFS, besides we detected PD-L1 in CTCs.

Method

We enrolled 112 NSCLC patients. CTC tests were performed at four time points (preoperative, pulmonary vein, intraoperative and postoperative) on every NSCLC patient who received surgery. The RNA of PD-L1 was tested by FISH. The levels of the PD-L1 mRNA and protein in tissue samples were detected.

Results

The CTCs in the PV were the highest (P< 0.001), and CTCs in the PPA were the lowest (P< 0.001). The PFS in the group with PV CTCs≥ 16/5 ml was shorter than that in the group with PV CTCs< 16/5 ml (11.1 months vs 21.2 months, respectively; P< 0.001). The PFS in the group with PPA CTCs≥ 3/5 ml was shorter than that in the group with CTCs< 3/5 ml (14.8 months vs 20.7 months, respectively; P< 0.001). The CTCs in stage I were lower than those in stage II-IV (P = 0.025). No linear relationship was found between the CTCs and tumor size (P> 0.05) or LN metastasis (P> 0.05). In total, fifty-two (50.5%) patients had positive PD-L1 expression in CTC. In PD-L1-positive CTC patients, the value of PD-L1 tissue expression was higher than that in PD-L1-negative CTC patients (P = 0.0153).

Conclusion

CTCs in the pulmonary vein can be an effective prognosis indicator of NSCLC patients.

Tumor-proximal liquid biopsy to improve diagnostic and prognostic performances of circulating tumor cells

Circulating tumor cell (CTC) detection and numeration are becoming part of the common clinical practice, especially for breast, colon, and prostate cancer. However, their paucity in peripheral blood samples is an obstacle for their identification. Several groups have tried to improve CTC recovery rate by developing highly sensitive cellular and molecular detection methods. However, CTCs are still difficult to detect in peripheral blood. Therefore, their recovery rate could be increased by obtaining blood samples from vessels close to the drainage territories of the invaded organ, when the anatomical situation is favorable. This approach has been tested mostly during tumor resection surgery, when the vessels nearest to the tumor are easily accessible. Moreover, radiological (including echo‐guided based and endovascular techniques) and/or endoscopic routes could be utilized to obtain CTC samples close to the tumor in a less invasive way than conventional biopsies. The purpose of this article is to summarize the available knowledge on CTC recovery from blood samples collected close to the tumor (i.e., in vessels located in the drainage area of the primary tumor or metastases). The relevance of such an approach for diagnostic and prognostic evaluations will be discussed, particularly for pancreatic ductal adenocarcinoma, colorectal adenocarcinoma, hepatocellular carcinoma, and non‐small‐cell lung cancer.

Inferring rates of metastatic dissemination using stochastic network models

The formation of metastases is driven by the ability of cancer cells to disseminate from the site of the primary tumour to target organs. The process of dissemination is constrained by anatomical features such as the flow of blood and lymph in the circulatory system. We exploit this fact in a stochastic network model of metastasis formation, in which only anatomically feasible routes of dissemination are considered. By fitting this model to two different clinical datasets (tongue & ovarian cancer) we show that incidence data can be modelled using a small number of biologically meaningful parameters. The fitted models reveal site specific relative rates of dissemination and also allow for patient-specific predictions of metastatic involvement based on primary tumour location and stage. Applied to other data sets this type of model could yield insight about seed-soil effects, and could also be used in a clinical setting to provide personalised predictions about the extent of metastatic spread.

Tumor microenvironmental plasmacytoid dendritic cells contribute to breast cancer lymph node metastasis via CXCR4/SDF-1 axis

PURPOSE

Plasmacytoid dendritic cells (PDCs) infiltration into breast cancer tissues is associated with poor prognosis. Also, CXCR4 shows compelling evidences to be exploited by cancer cells to migrate to distant sites. The present study investigated lymph node metastasis in the light of PDCs infiltration and the potential cross talk with CXCR4/SDF-1 chemokine axis.

METHODS

We assessed circulating PDCs proportions drained from the axillary tributaries, and the in situ expression of both CD303 and CXCR4 in breast cancer patients with positive lymph nodes (pLN) and negative lymph nodes (nLN) using immunohistochemistry and flow cytometry. We also analyzed the expression of SDF-1 in lymph nodes of pLN and nLN patients. We studied the effect of the secretome of PDCs of pLN and nLN patients on the expression of CXCR4 and activation of NF-κB in human breast cancer cell lines SKBR3 and MCF-7. TNF-α mRNA expression level in PDCs from both groups was determined by qPCR.

RESULTS

Our findings indicate increased infiltration of PDCs in breast cancer tissues of pLN patients than nLN patients, which correlates with CXCR4⁺ cells percentage. Interestingly, SDF-1 is highly immunostained in lymph nodes of pLN patients compared to nLN patients. Our in vitro experiments demonstrate an upregulation of NF-κB expression and CXCR4 cells upon stimulation with PDCs secretome of pLN patients than those of nLN patients. Also, PDCs isolated from pLN patients exhibited a higher TNF-α mRNA expression than nLN patients. Treatment of MCF-7 cell lines with TNF-α significantly upregulates CXCR4 expression.

CONCLUSIONS

Our findings suggest a potential role for microenvironmental PDCs in breast cancer lymph node metastasis via CXCR4/SDF-1 axis.

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.

Intraoperative detection of circulating tumor cells in pulmonary venous blood during metastasectomy for colorectal lung metastases

Circulating tumor cells (CTC) have been studied extensively in various tumor types and are a well-established prognosticator in colorectal cancer (CRC). This is the first study to isolate CTC directly from the tumor outflow in secondary lung tumors. For this purpose in 24 patients with CRC who underwent pulmonary metastasectomy in curative intent blood was drawn intraoperatively from the pulmonary vein (tumor outflow). In 22 samples CTC-enumeration was performed using CellSieve-microfilters and immunohistochemical- and Giemsa-staining. Additionally 10 blood samples were analyzed using the CellSearch-System. We could isolate more CTC in pulmonary venous blood (total 41, range 0-15) than in samples taken from the periphery at the same time (total 6, range 0-5, p = 0.09). Tumor positive lymph nodes correlated with presence of CTC in pulmonary venous blood as in all cases CTC were present (p = 0.006). Our findings suggest a tumor cell release from pulmonary metastases in CRC and a correlation of CTC isolated from the tumor outflow with established negative prognostic markers in metastasized CRC. The presented data warrant further investigations regarding the significance of local tumor compartments when analyzing circulating markers and the possibility of tumor cell shedding from secondary lung tumors.

Clinical evaluation of 4 types of microRNA in serum as biomarkers of esophageal squamous cell carcinoma

To the best of our knowledge, there is currently no specific biomarker for esophageal cancer used in clinical practice. However, studies consider that microRNAs (miRNAs/miRs) could have useful implications in clinical practice. The present study aimed to investigate the feasibility of using serum microRNAs as biomarkers for esophageal squamous cell carcinoma (ESCC). Using reverse transcription-quantitative polymerase chain reaction, the expression levels of serum miR-21, miR-25, miR-145 and miR-203 were detected in 31 untreated patients with ESCC (EC-UT), 35 inactive period patients with ESCC following treatment (EC-T), 33 patients with esophageal benign disease (benign) and 32 healthy donors (healthy). Furthermore, the ability of these microRNAs to function as biomarkers of ESCC alone and in combination were investigated. The expression levels of serum miR-21, miR-25 and miR-145 in EC-UT were significantly higher than in the other groups (P<0.001). High sensitivity and specificity were shown when miRNAs were used as biomarkers for ESCC, particularly miR-21 and the combination of miR-21 with miR-145. Comparing EC-UT with healthy, benign and EC-T groups, and a combined group (3 groups set as 1 negative control), the sensitivity and specificity of miR-21 were 71.0 and 96.9, 74.2 and 87.9, 77.4 and 82.9, and 74.2 and 88.0%, respectively. The combined sensitivity and specificity of miR-21 and miR-145 were 71.0 and 96.9, 90.9 and 72.7, 97.1 and 82.9, and 80.6 and 80.0%, respectively. In conclusion, 3 types of miRNA (miR-21, miR-25 and miR-145) in serum could serve as potential biomarkers for ESCC. Furthermore, the expression level of miR-145 in serum was upregulated, compared with the downregulation reported in previous studies in ESCC tissues and cells.

The clinical value of circulating tumour cells (CTCs) in patients undergoing pulmonary metastasectomy for metastatic colorectal cancer

Background

Circulating tumour cells (CTCs) are a potential surrogate for distant metastasis and are considered a useful clinical prognostic marker for metastatic colorectal cancer (mCRC). This prospective study evaluated the preoperative CTC count as a prognostic factor for pulmonary metastasectomy in mCRC patients.

Methods

Seventy-nine mCRC patients who underwent curative-intent pulmonary metastasectomy were included. Preoperatively, 7.5 mL of peripheral blood from each patient was quantitatively evaluated for CTCs with the CellSearch^® system. The clinical significance of CTC count was evaluated according to Kaplan-Meier analyses and log-rank test. Multivariate analyses of the perioperative variables were performed.

Results

The distribution of CTC counts were as follows; 0 in 66 patients (83.5%), 1 in eight patients (10.1%), 2 in three patients (3.8%), and 3 and 6 in one patient (1.3%). The patients with multiple CTCs (CTC count ≥2) had significant shorter disease-free survival (DFS) (P=0.005, median DFS; 19.8 vs. 8.6 months) and overall survival (OS) (P=0.035, median DFS; not reached vs. 37.8 months), respectively. Multivariate analysis showed the patients with multiple CTCs had elevated risk of recurrence [hazard ratio (HR), 3.28; 95% confidence interval (CI), 1.24-8.67; P=0.017].

Conclusions

The detected rate of CTCs was quite low in mCRC patients who underwent pulmonary metastasectomy. The patient with multiple CTCs had shorter DFS in this study. The larger prospective clinical study is needed to establish the meaning of CTC in mCRC candidate for pulmonary metastasectomy.

Circulating tumor cells predict survival benefit from chemotherapy in patients with lung cancer

Background

This meta-analysis was to explore the clinical significance of circulating tumor cells (CTCs) in predicting the tumor response to chemotherapy and prognosis of patients with lung cancer.

Methods

We searched PubMed, Embase, Cochrane Database, Web of Science and reference lists of relevant articles. Our meta-analysis was performed by Stata software, version 12.0, with a random effects model. Risk ratio (RR), hazard ratio (HR) and 95% confidence intervals (CI) were used as effect measures.

Results

8 studies, including 453 patients, were eligible for analyses. We showed that the disease control rate (DCR) in CTCs-negative patients was significantly higher than CTCs-positive patients at baseline (RR = 2.56, 95%CI [1.36, 4.82], p < 0.05) and during chemotherapy (RR = 9.08, CI [3.44, 23.98], p < 0.001). Patients who converted form CTC-negative to positive or persistently positive during chemotherapy had a worse disease progression than those with CTC-positive to negative or persistently negative (RR = 8.52, CI [1.66, 43.83], p < 0.05). Detection of CTCs at baseline and during chemotherapy also indicated poor overall survival (OS) (baseline: HR = 3.43, CI [2.21, 5.33], p<0.001; during chemotherapy: HR = 3.16, CI [2.23, 4.48], p < 0.001) and progression-free survival (PFS) (baseline: HR = 3.16, 95%CI [2.23, 4.48], p < 0.001; during chemotherapy: HR = 3.78, CI [2.33, 6.13], p < 0.001).

Conclusions

Detection of CTCs in peripheral blood indicates poor tumor response to chemotherapy and poor prognosis in patients with lung cancer.

Positive correlation between postoperative tumor recurrence and changes in circulating tumor cell counts in pulmonary venous blood (pvCTC) during surgical manipulation in non-small cell lung cancer

Background

In non-small cell lung cancer (NSCLC), circulating tumor cells (CTC) are shed and circulate to the peripheral blood through the pulmonary vein. Previously, CTC count in pulmonary venous blood (pvCTC) was shown to significantly increase after surgical manipulation. Therefore, we assessed the correlation between the changes in the pvCTC count (ΔpvCTC) and clinical outcomes.

Methods

Consecutive patients with peripheral-type, NSCLC, who underwent lobectomy or bi-lobectomy through open thoracotomy, were enrolled prospectively. Before and after lobectomy, 2.5 mL of blood was drawn from the associated lobar pulmonary vein (PV), and was served for the quantitative evaluation of CTC using the CellSearch^® system. The cut-off point of ΔpvCTC was determined according to clinical outcomes and ΔpvCTC using receiver operation characteristic (ROC) curve. Then the correlation between ΔpvCTC and clinical outcomes was evaluated by Kaplan-Meier analyses and log-rank test. In addition, the correlation between ΔpvCTC and perioperative variables was assessed.

Results

A total of 30 patients were enrolled, tumor recurrence occurred in 11 patients over a median follow-up of 64.4 months. Of these, 7 patients had distant metastasis and 4 had local recurrence. The median ΔpvCTC was 49 cells/2.5 mL, and pvCTC-count was increased during surgical manipulation in 24 patients (80%). We divided patients into two groups based on ΔpvCTC with the cut-off value as 119 cells/2.5 mL according to ROC curve. Significant shorter time to distant metastasis (TDM) (P=0.0123) was observed in high ΔpvCTC group (ΔpvCTC ≥119 cells/2.5 mL) than low ΔpvCTC group (ΔpvCTC <119 cells/ 2.5mL). Neither disease-free survival (DFS) nor overall survival (OS) was significantly correlated with ΔpvCTC.

Conclusions

Increasing pvCTC count during surgical manipulation was significantly correlated with postoperative distant metastasis in completely resected NSCLC patients. Significant shorter TDM was observed in patient with high ΔpvCTC group.

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.

Detection of circulating tumor cells in pulmonary venous blood for resectable non-small cell lung cancer

Intraoperative manipulation causes circulating tumor cell (CTC) shedding into the blood and accelerates metastasis in non-small cell lung cancer (NSCLC). The present study was conducted to assess the degree of dissemination resulting from surgery and to explore the biological features of CTCs. In patients with NSCLC who underwent complete resection, the pulmonary vein (PV) was isolated and stapled following thoracotomy. The number of CTCs retained per 7.5 ml PV blood (CTC-PV) and peripheral blood were detected. Following hematopoietic cell depletion, a xenograft assay was performed using the CTC-PV. A total of 32 consecutive patients were enrolled in the study, the majority of whom had CTCs in their PV blood (n=29, 90.6%). Circulating tumor microemboli (CTM) were identified in 12 patients (37.5%). The CTC-PV and CTM-PV counts were positively correlated with tumor size (P=0.012 and P=0.028, respectively). Patients with small tumors (<3.0 cm) also had considerable CTC-PV and CTM-PV. A total of 8 patients received platinum-based chemotherapy prior to surgery. The CTC-PV and CTM-PV counts in patients with partial response were significantly lower than those in patients with stable disease or who did not receive induction therapy (P=0.025 and P=0.044, respectively). The enriched CTC-PV from 3 patients were injected into 3 immunodeficient mice, and 1 mouse developed a xenograft tumor. To conclude, the present study indicates that intraoperative manipulation contributes to the hematogenous dissemination of tumorigenic CTCs and CTM. Lobectomy is recommended for lung cancer of any tumor size and stage according to oncological principles, in addition to ligating the PV, if possible, prior to any other treatment.

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.

Frequency and clinical impact of preoperative circulating tumor cells in resectable non-metastatic lung adenocarcinomas

OBJECTIVES

Despite successful surgery, 30-50% of patients with resectable non-small cell lung cancer develop tumor recurrence within 5 years of surgery.

MATERIALS AND METHODS

In this prospective study, we performed CTC enumerations in 40 patients with non-metastatic lung adenocarcinoma (NMLA) using a size-based microfilter. Additionally, cfDNA isolated from plasma was analyzed in 35 out of 40 patients.

RESULTS

CTCs were identified in 15 out of 40 patients (37.5%) with a range of 1-44 cells, whereas mutated cfDNA was only detected in 3 out of 35 patients (8.6%). Disease-free survival (DFS) was significantly associated with CTC positivity (log-rank p=0.025), grading (log-rank p=0.019), tumor stage (log-rank p=0.025) and lymph node status (log-rank p=0.029). Multivariate analysis, including tumor stage and grading, showed that CTC positivity (p=0.006), grading (0.039) and tumor stage (p=0.022) were independently associated with DFS.

CONCLUSION

Our study found that microfilter-based CTC enumeration in NMLA patients is an independent predictor of worse DFS. The used NGS-based cfDNA characterization had limited sensitivity to be clinically informative in our study cohort. CTC assessment before surgery can thus identify NMLA patients at high risk of disease recurrence.

Poor Prognosis Indicated by Venous Circulating Tumor Cell Clusters in Early-Stage Lung Cancers

Early detection of metastasis can be aided by circulating tumor cells (CTC), which also show potential to predict early relapse. Because of the limited CTC numbers in peripheral blood in early stages, we investigated CTCs in pulmonary vein blood accessed during surgical resection of tumors. Pulmonary vein (PV) and peripheral vein (Pe) blood specimens from patients with lung cancer were drawn during the perioperative period and assessed for CTC burden using a microfluidic device. From 108 blood samples analyzed from 36 patients, PV had significantly higher number of CTCs compared with preoperative Pe (P < 0.0001) and intraoperative Pe (P < 0.001) blood. CTC clusters with large number of CTCs were observed in 50% of patients, with PV often revealing larger clusters. Long-term surveillance indicated that presence of clusters in preoperative Pe blood predicted a trend toward poor prognosis. Gene expression analysis by RT-qPCR revealed enrichment of p53 signaling and extracellular matrix involvement in PV and Pe samples. Ki67 expression was detected in 62.5% of PV samples and 59.2% of Pe samples, with the majority (72.7%) of patients positive for Ki67 expression in PV having single CTCs as opposed to clusters. Gene ontology analysis revealed enrichment of cell migration and immune-related pathways in CTC clusters, suggesting survival advantage of clusters in circulation. Clusters display characteristics of therapeutic resistance, indicating the aggressive nature of these cells. Thus, CTCs isolated from early stages of lung cancer are predictive of poor prognosis and can be interrogated to determine biomarkers predictive of recurrence. Cancer Res; 77(18); 5194-206. ©2017 AACR.

Clinical utility of circulating tumor cells in patients with non-small-cell lung cancer

Several different studies have addressed the role of the circulating tumor cells (CTC) in non-small-cell lung cancer (NSCLC). In particular, the potential of CTC analysis in the early diagnosis of NSCLC and in the prediction of the outcome of patients with early and advanced NSCLC have been explored. A major limit of these studies is that they used different techniques for CTC isolation and enumeration, they employed different thresholds to discriminate between high- and low-risk patients, and they enrolled heterogeneous and often small cohort of patients. Nevertheless, the results of many studies are concordant in indicating a correlation between high CTC count and poor prognosis in both early and advanced NSCLC. The reduction of CTC number following treatment might also represent an important indicator of sensitivity to therapy in patients with metastatic disease. Preliminary data also suggest the potential for CTC analysis in the early diagnosis of NSCLC in high-risk individuals. However, these findings need to be confirmed in large prospective trials in order to be transferred to the clinical practice. The molecular profiling of single CTC in NSCLC might provide important information on tumor biology and on the mechanisms involved in tumor dissemination and in acquired resistance to targeted therapies. In this respect, xenografts derived from CTC might represent a valuable tool to investigate these phenomena and to develop novel therapeutic strategies.

Identification of a Human Airway Epithelial Cell Subpopulation with Altered Biophysical, Molecular, and Metastatic Properties

Lung cancers are documented to have remarkable intratumoral genetic heterogeneity. However, little is known about the heterogeneity of biophysical properties, such as cell motility, and its relationship to early disease pathogenesis and micrometastatic dissemination. In this study, we identified and selected a subpopulation of highly migratory premalignant airway epithelial cells that were observed to migrate through microscale constrictions at up to 100-fold the rate of the unselected immortalized epithelial cell lines. This enhanced migratory capacity was found to be Rac1-dependent and heritable, as evidenced by maintenance of the phenotype through multiple cell divisions continuing more than 8 weeks after selection. The morphology of this lung epithelial subpopulation was characterized by increased cell protrusion intensity. In a murine model of micrometastatic seeding and pulmonary colonization, the motility-selected premalignant cells exhibit both enhanced survival in short-term assays and enhanced outgrowth of premalignant lesions in longer-term assays, thus overcoming important aspects of "metastatic inefficiency." Overall, our findings indicate that among immortalized premalignant airway epithelial cell lines, subpopulations with heritable motility-related biophysical properties exist, and these may explain micrometastatic seeding occurring early in the pathogenesis of lung cancer. Understanding, targeting, and preventing these critical biophysical traits and their underlying molecular mechanisms may provide a new approach to prevent metastatic behavior. Cancer Prev Res; 10(9); 514-24. ©2017 AACRSee related editorial by Hynds and Janes, p. 491.

Circulating tumor cells in peripheral and pulmonary venous blood predict poor long-term survival in resected non-small cell lung cancer patients

We tested the hypothesis that circulating tumor cells (CTCs) in preoperative peripheral blood (PPB) and intraoperative pulmonary venous blood (IPVB) could predict poor long-term survival in resected non-small cell lung cancer (NSCLC) patients. CTCs were separated from blood using magnetic beads coated with antibodies against epithelial-cell adhesion molecule (EpCAM) via magnetic-activated cell sorting (MACS). CTCs were quantified with fluorescence-labeled antibodies against pan-cytokeratin through flow cytometry. CTCs were quantified in PPB and IPVB in 23 consecutive stage I-IIIA patients with resected NSCLC. The association between CTCs and prognosis in these patients was evaluated after a 5-year follow-up. In NSCLC patients, outcomes were assessed according to CTC levels at surgery. NSCLC patients identified as high-risk groups exhibited >5 CTCs/15 mL in PPB and >50 CTCs/15 mL in IPVB. Univariate Cox proportional-hazards regression analysis showed that the CTC count in PPB or IPVB was an independent risk factor for tumor-free surivival (TFS) and overall survival (OS). The high-risk group of patients had a shorter median TFS (22 months vs. >60.0 months, p < 0.0012) and shorter OS (27 months vs. >60 months, p < 0.0015). The number of CTCs counted in PPB and IPVB was an independent risk factor for TFS and OS in resected NSCLC patients.

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.

Perioperative circulating tumor cells in surgical patients with non-small cell lung cancer: does surgical manipulation dislodge cancer cells thus allowing them to pass into the peripheral blood?

PURPOSE

We herein evaluated the status of circulating tumor cells (CTC) dislodged from the tumor during surgery in patients who underwent pulmonary resection for non-small cell lung cancer (NSCLC) to assess the clinical implications.

METHODS

Tumor cells in the peripheral arterial blood before surgery (Before) and immediately after lung resection (After) and in the blood from the pulmonary vein of the resected lung were detected using a size selective method. The clinicopathological characteristics and the prognosis were then analyzed according to the CTC status: no tumor cells detected (N), single tumor cell or total number less than 4 cells (S), and existence of clustered cells (C).

RESULTS

According to the CTC status, the patients were classified into the following three groups: Before-C and After-C, Group I (n = 6); Before-S or N and After-C, Group II (n = 9); and Before-S or N and After-S or N, Group III (n = 8). Group III showed a high rate of p-stage IA, smaller tumor size, lower CEA level, lower SUVmax level, and a higher relapse-free survival rate than the other groups.

CONCLUSIONS

CTCs were detected in patients after undergoing lung resection, some of which may have been dislodged by the surgical procedure. The presence of clustered CTCs after the operation indicated an unfavorable outcome.

Circulating Tumor Cells Identify Early Recurrence in Patients with Non-Small Cell Lung Cancer Undergoing Radical Resection

Background

Surgery is the treatment of choice for patients with non-small cell lung cancer (NSCLC) stages I-IIIA. However, more than 20% of these patients develop recurrence and die due to their disease. The release of tumor cells into peripheral blood (CTCs) is one of the main causes of recurrence of cancer. The objectives of this study are to identify the prognostic value of the presence and characterization of CTCs in peripheral blood in patients undergoing radical resection for NSCLC.

Patients and Methods

56 patients who underwent radical surgery for previously untreated NSCLC were enrolled in this prospective study. Peripheral blood samples for CTC analysis were obtained before and one month after surgery. In addition CTCs were phenotypically characterized by epidermal growth factor receptor (EGFR) expression.

Results

51.8% of the patients evaluated were positive with the presence of CTCs at baseline. A decrease in the detection rate of CTCs was observed in these patients one month after surgery (32.1%) (p = 0.035). The mean number of CTCs was 3.16 per 10 ml (range 0–84) preoperatively and 0.66 (range 0–3) in postoperative determination. EGFR expression was found in 89.7% of the patients at baseline and in 38.9% patients one month after surgery. The presence of CTCs after surgery was significantly associated with early recurrence (p = 0.018) and a shorter disease free survival (DFS) (p = .008). In multivariate analysis CTC presence after surgery (HR = 5.750, 95% CI: 1.50–21.946, p = 0.010) and N status (HR = 0.296, 95% CI: 0.091–0.961, p = 0.043) were independent prognostic factors for DFS.

Conclusion

CTCs can be detected and characterized in patients undergoing radical resection for non-small cell lung cancer. Their presence might be used to identify patients with increased risk of early recurrence.

Adjuvant therapy following surgery in non-small cell lung cancer (NSCLC)

Non-small cell lung cancer (NSCLC) accounts for 80-90 % of cases of primary lung cancer. Although surgery is recommended as the primary treatment for early-stage NSCLC, the prognosis is unsatisfactory even when complete resection is achieved. Recent clinical trials have shown that postoperative adjuvant chemotherapy with cytotoxic agents, namely uracil-tegafur (UFT) for stage IA (>2 cm in diameter)-IB patients or cisplatin-based regimens for stage II-IIIA patients, improves the prognosis, and adjuvant chemotherapy is recommended as the "standard treatment of care." However, adjuvant chemotherapy provides only a modest 5-year survival benefit of 4 % and may sometimes be fatal. To improve the risk-benefit balance of adjuvant chemotherapy, targeting agents such as antibodies against vascular endothelial growth factor (VEGF) and tyrosine-kinase inhibitors of epidermal growth factor receptor (EGFR-TKIs) are being evaluated in ongoing adjuvant trials. Another promising approach may be the individualization of adjuvant chemotherapy based on biomarkers that may predict the prognosis or benefits associated with adjuvant chemotherapy. The current status and future perspectives of adjuvant chemotherapy for NSCLC are reviewed and discussed.

Lung excision of non-small-cell lung cancer leaves cancer cells in residual lobe: cytological detection using pulmonary vein blood

OBJECTIVES

Lung excision to treat non-small-cell lung cancer (NSCLC) is associated with a worse prognosis when compared with a lobectomy. Cancer relapse may be caused by tumour cells remaining in the residual lobe, the possibility of dislodged cancer cells in the residual lobe is assessed using pulmonary vein blood (PVB) from the resected lung.

METHODS

Twenty-eight patients with pathological stage I NSCLC who underwent lung excision followed by a lobectomy were evaluated according to the status of isolated tumour cells (ITCs) (origin of circulating tumour cells) in PVB from the resected lobe. Survival was also assessed according to the status of ITCs.

RESULTS

The rate of ITC presence was 60.7% and depended on margin distance/tumour size (M/T) with a threshold of 1.0-30.8% (4/13) in M/T greater than or equal to 1.0 and 86.7% (13/15) in M/T smaller than 1.0 (P = 0.001). PVB-ITC status was no ITCs (N) in 11 (39.3%), only singular cells (S) in 13 (50.0%) and clustered cells (C) in 4 (14.3%). In addition, the survival status of patients with clustered cells was exclusively wrong.

CONCLUSION

After pulmonary excision for lung cancer, tumour cells remain in the residual lobe and the morphology of which may indicate recurrence.

Pulmonary venous blood sampling significantly increases the yield of circulating tumor cells in early-stage lung cancer

OBJECTIVE

To identify circulating tumor cells (CTCs) in the blood of patients with early-stage lung cancer and to show that sampling pulmonary vein (PV) blood using microfluidic chip technology will yield significantly more CTCs. Improving early detection of lung cancer is critical to improving lung cancer survival. Reproducible detection of CTCs is limited currently in early stage tumors.

METHODS

Patients undergoing pulmonary resection had PV blood drawn before resection. Peripheral blood was sampled at preoperative, intraoperative, and postoperative times. Samples were analyzed on microfluidic chips using antibody-based capture.

RESULTS

A total of 32 patients with primary lung cancer were evaluated. Twenty patients had 1 or more CTCs detected in at least 1 sample (62.5%). The mean number of CTCs from peripheral vein sources at the preoperative, intraoperative, and postoperative time points was 1.3, 1.9, and 0.6 respectively. The average number of CTCs in the PV was 340.0 (range, 0.0-5422.50; P > .01). When PV CTCs were present, the number of CTCs was correlated with pathological tumor size (P = .0236). The number of PV CTCs was not correlated with any other clinical feature (eg, smoking status, preoperative or postoperative stage). Furthermore, the number of PV CTCs was significantly higher when preoperative bronchoscopic biopsy was performed, compared with computed tomography-guided biopsy (P = .0311). Seven patients had evidence of CTC clusters, or microemboli.

CONCLUSIONS

With a single vein draining the entire tumor basin, lung cancers are unique, allowing the high-yield isolation of CTCs from the PV. This method may facilitate future studies to improve the detection and analysis of early-stage lung CTCs.

Prognostic and predictive biomarkers in early stage NSCLC: CTCs and serum/plasma markers

Resection of early stage non-small cell lung cancer (NSCLC) offers patients the best hope of cure, however recurrence rates post-resection remain high suggesting the presence of micro-metastatic disease at the time of surgery undetected by standard staging methods. A critical step in the metastatic cascade is the entry of tumor cells into the circulation enabling their distribution to and seeding of distant organs. This review explores the evidence for predictive and prognostic circulating biomarkers in the early stage NSCLC population. We summarize studies that have explored a variety of targets including circulating proteins, nucleic acids and more recently circulating tumor cells (CTCs) as potentially clinically relevant biomarkers in the early stage setting. Circulating biomarkers may add clinically relevant information about the biological behavior of tumors over and above that provided by pathological staging. Improvement in the stratification of patients according to the likelihood of metastatic relapse after radical treatments such as surgical resection could allow more effective targeting of systemic therapies such as adjuvant chemotherapy.

Circulating tumor cells in lung cancer: detection methods and clinical applications

Circulating tumor cells (CTCs) are tumor cells that have disseminated from primary and metastatic sites, and circulate in the bloodstream. Advanced immunological and molecular-based methods can be used to detect and analyze the cells with the characteristics of tumor cells, and can be detected and analyzed in the blood of cancer patients. The most commonly used methods in lung cancer combine the processes of immunomagnetic enrichment and immunocytochemical detection, morphology-based enrichment coupled with reverse transcriptase polymerase chain reaction (RT-PCR), and RT-PCR alone. CTC analysis is considered a liquid biopsy approach for early diagnosis, risk stratification, evaluation of curative efficacy, and early detection of lung cancer relapse. In this review, we discuss the present techniques for analyzing CTCs, and the restrictions of using these methods in lung cancer. We also review the clinical studies in lung cancer and discuss the underlying associations between these studies and their future applications to this disease.

Predictive and prognostic value of circulating tumor cell detection in lung cancer: a clinician's perspective

There is increasing evidence for the use of circulating tumor cells (CTCs) as a "liquid biopsy" for early detection of lung cancer recurrence, prognosticating disease and monitoring treatment response. Further, CTC molecular analysis and interrogation of single cells hold significant potential in providing insights into tumor biology and the metastatic process. Ongoing research will likely see the translation of CTCs as a prognostic and predictive biomarker in both small cell, and non-small cell, lung cancer to routine clinical practice.

A filter-flow perspective of haematogenous metastasis offers a non-genetic paradigm for personalised cancer therapy

Research into mechanisms of haematogenous metastasis has largely become genetic in focus, attempting to understand the molecular basis of 'seed-soil' relationships. Preceding this biological mechanism is the physical process of dissemination of circulating tumour cells (CTCs) in the circulation. Patterns of metastatic spread have been previously quantified using the metastatic efficiency index, a measure quantifying metastatic incidence for a given primary-target organ pair and the relative blood flow between them. We extend this concept to take into account the reduction in CTCs which occurs in organ capillary beds connected by a realistic vascular network topology. Application to a dataset of metastatic incidence reveals that metastatic patterns depend strongly on assumptions about the existence and location of micrometastatic disease which governs CTC dynamics on the network, something which has heretofore not been considered - an oversight which precludes our ability to predict metastatic patterns in individual patients.

Tumor cells are dislodged into the pulmonary vein during lobectomy

OBJECTIVE

Intraoperative tumor shedding may facilitate tumor dissemination. In earlier studies, shed tumor cells were defined primarily by cytomorphological examination, and normal epithelial cells could not always be distinguished from tumor cells. We sought to accurately identify tumor cells using single-cell sequencing and determine whether these cells were mobilized into the circulation during pulmonary lobectomy.

METHODS

Forty-two blood samples collected from the tumor-draining pulmonary vein at the end of lobectomy procedures were analyzed. Arrays of nanowells were used to enumerate and retrieve single EpCAM(+) cells. Targeted sequencing of 10 to 15 cells and nested polymerase chain reaction of single cells detected somatic mutations in shed epithelial cells consistent with patient-matched tumor but not normal tissue.

RESULTS

The mean number of EpCAM(+) cells in video-assisted thoracoscopy (VATS) lobectomy (no wedge) specimens (n = 16) was 165 (median, 115; range, 0-509) but sampling cells from 3 patients indicated that only 0% to 38% of the EpCAM(+) cells were tumor cells. The mean number of EpCAM(+) cells in VATS lobectomy (wedge) specimens (n = 12) was 1128 (median, 197; range, 47-9406) and all of the EpCAM(+) cells were normal epithelial cells in 2 patients sampled. The mean number of EpCAM(+) cells in thoracotomy specimens (n = 14) was 238 (median, 22; range, 9-2920) and 0% to 50% of total EpCAM(+) cells were tumor cells based on 4 patients sampled.

CONCLUSIONS

Surgery mobilizes tumor cells into the pulmonary vein, along with many normal epithelial cells. EpCAM alone cannot differentiate between normal and tumor cells. On the other hand, single-cell genetic approaches with patient-matched normal and tumor tissues can accurately quantify the number of shed tumor cells.

Significant increase in circulating tumour cells in pulmonary venous blood during surgical manipulation in patients with primary lung cancer

OBJECTIVES

Circulating tumour cells (CTCs) are tumour cells shed from a primary tumour and circulate in the peripheral blood after passing through the drainage vein. In previous studies, we showed that high numbers of CTCs were detected in the drainage pulmonary venous blood of most patients with resectable primary lung cancer, whereas only low numbers of CTCs were detected in the peripheral blood of some patients. Accordingly, this prospective study was conducted to assess changes in CTCs in the drainage pulmonary vein (PV) during lung cancer surgery.

METHODS

A total of 30 consecutive peripheral-type primary lung cancer patients who underwent lobectomy (or right upper and middle bilobectomy) through open thoracotomy were included. For each patient, 2.5 ml of blood was sampled from the lobar PV of the primary tumour site before and after surgical manipulation for lobectomy. The CTCs were evaluated quantitatively with the CellSearch® system.

RESULTS

Before surgical manipulation, CTCs were detected in PV blood in the majority of patients (22 of 30, 73.3%), although CTCs were detected in peripheral blood in only two patients (6.7%). The median number of CTCs in the PV (pvCTC-count) before surgical manipulation was 4.0 cells/2.5 ml, and there was no significant correlation between pvPV-count and any clinicopathological characteristic, including tumour size, progression and histological type. After surgical manipulation, at the time of completion of the lobectomy, the pvCTC-count significantly increased (median, 60.0 cells/2.5 ml; P = 0.001). The increase in pvCTC-count was significantly associated with microscopic lymphatic tumour invasion (ly); pvCTC-count significantly increased in ly-positive patients (pvCTC-count before and after surgical manipulation, 4.0 and 90.5 cells/2.5 ml, respectively; P = 0.006), but not in ly-negative patients (3.5 and 7.0 cells/2.5 ml, respectively; P = 0.153). The increase in pvCTC-count was not significantly associated with any other clinicopathological factor or with any surgical procedure, including the sequence of vessel interruption.

CONCLUSIONS

We documented a significant increase in CTC count in drainage PV blood after surgical manipulation, especially in tumours with lymphatic invasion. We are awaiting survival data at 5 year follow-up examination, which may provide clinical significance of the pvCTC-count.

Stabilization of circulating tumor cells in blood using a collection device with a preservative reagent

BACKGROUND

The enumeration and characterization of circulating tumor cells (CTCs) in the blood of cancer patients is useful for cancer prognostic and treatment monitoring purposes. The number of CTCs present in patient blood is very low; thus, robust technologies have been developed to enumerate and characterize CTCs in patient blood samples. One of the challenges to the clinical utility of CTCs is their inherent fragility, which makes these cells very unstable during transportation and storage of blood samples. In this study we investigated Cell-Free DNA BCT™ (BCT), a blood collection device, which stabilizes blood cells in a blood sample at room temperature (RT) for its ability to stabilize CTCs at RT for an extended period of time.

METHODS

Blood was drawn from each donor into K3EDTA tube, CellSave tube and BCT. Samples were then spiked with breast cancer cells (MCF-7), transported and stored at RT. Spiked cancer cells were counted using the Veridex CellSearch™ system on days 1 and 4. The effect of storage on the stability of proteins and nucleic acids in the spiked cells isolated from K3EDTA tube and BCT was determined using fluorescence staining and confocal laser scanning microscopy.

RESULTS

MCF-7 cell recovery significantly dropped when transported and stored in K3EDTA tubes. However, in blood collected into CellSave tubes and BCTs, the MCF-7 cell count was stable up to 4 days at RT. Epithelial cell adhesion molecule (EpCAM) and cytokeratin (CK) in MCF-7 cells isolated from BCTs was stable at RT for up to 4 days, whereas in MCF-7 cells isolated from K3EDTA blood showed reduced EpCAM and CK protein expression. Similarly, BCTs stabilized c-fos and cyclin D1 mRNAs as compared to K3EDTA tubes.

CONCLUSION

Cell-Free DNA™ BCT blood collection device preserves and stabilizes CTCs in blood samples for at least 4 days at RT. This technology may facilitate the development of new non-invasive diagnostic and prognostic methodologies for CTC enumeration as well as characterization.

Prognostic significance of circulating tumor cells in non-small-cell lung cancer patients: a meta-analysis

Background

The prognostic significance of circulating tumor cells (CTCs) detected in patients with non-small-cell lung cancer (NSCLC) is still inconsistent. We aimed to assess the prognostic relevance of CTCs using a meta-analysis.

Methods

We searched PubMed, Web of Science and EMBASE for relevant studies that assessed the prognostic relevance of CTCs in NSCLC. Statistical analyses were conducted to calculate the summary incidence, odds ratio, relative risks (RRs) and 95% confidence intervals (CIs) using fixed or random-effects models according to the heterogeneity of included studies.

Results

A total of 20 studies, comprising 1576 patients, met the inclusion criteria. In identified studies, CTCs were not correlated with histology (adenocarcinoma vs squamous cell carcinoma) (odds ratio [OR]  =  0.88; 95% confidence interval [CI]: 0.59–1.33; Z = –0.61; P = 0.545). However, pooled analyses showed that CTCs were associated with lymph node metastasis (OR = 2.06; 95% CI: 1.18–3.62; Z = 2.20; P = 0.027) and tumor stage (OR  = 1.95; 95% CI: 1.08–3.54; Z = 2.53; P = 0.011). Moreover, CTCs were significantly associated with shorter overall survival (relative risk [RR]  = 2.19; 95% CI: 1.53–3.12; Z = 4.32; P<0.0001) and progression-free/disease-free survival (RR  = 2.14; 95% CI: 1.36–3.38; Z = 3.28; P<0.0001).

Conclusion

The presence of CTCs indicates a poor prognosis in patients with NSCLC. Further well-designed prospective studies are required to explore the clinical applications of CTCs in lung cancer.

Innovative method using circulating tumor cells for prediction of the effects of induction therapy on locally advanced non-small cell lung cancer

Background

The existence of circulating tumor cells (CTCs) in patients with lung cancer has been reported. The purpose of this study was to assess whether CTCs are predictive of the pathological effects of induction chemoradiotherapy for patients with non-small cell lung cancer.

Methods

Patients who underwent induction chemoradiotherapy followed by surgery were compared with those who underwent surgery alone. Peripheral and pulmonary venous blood samples from the involved lobe were collected intraoperatively, and the number of CTCs was counted using the CellSearch™ system, an epithelial cell adhesion molecule-based immunomagnetic technique.

Results

Of the 9 patients who underwent induction therapy, 4 achieved pathological CR, 4 achieved major response, and 1 achieved minor response. All patients who underwent induction therapy and surgery alone were negative for CTCs in peripheral blood. In the induction therapy group, 4 patients showing pathological CR were negative for CTCs in pulmonary venous blood (pvCTCs) and 5 showing major/minor response were positive (mean, 57.8 cells). The numbers of CTCs in patients showing major/minor response were significantly higher than those in patients showing pathological CR (p = 0.012, Mann–Whitney U test). All 6 patients undergoing surgery alone were positive for pvCTCs (mean, 207.5 cells), showing a significant difference from those undergoing induction therapy (p = 0.038).

Conclusions

The existence of CTCs in pulmonary venous blood reflects pathological non-CR, and therapeutic pathological response may be predicted by pvCTC measurement.

Multiplex PCR-based detection of circulating tumor cells in lung cancer patients using CK19, PTHrP, and LUNX specific primers

INTRODUCTION

The aim of this study was to develop a multiplex polymerase chain reaction (PCR)-based method for detection of circulating tumor cells in peripheral blood of lung cancer (LC) patients.

PATIENTS AND METHODS

Peripheral blood was collected from 71 healthy donors and 125 LC patients at different pathological stages. Samples were analyzed using multiplex PCR, and specific primers for CK19, PTHrP, and LUNX mRNA. The sensitivity of our method was set at 10 LC cells (A549 cells) in 3 mL of peripheral blood of healthy donors using spiking experiments.

RESULTS

The detection rates in LC patients for CK19, PTHrP, and LUNX were 45.6%, 64.8%, and 28%, and in healthy individuals were 7%, 7%, and 5.6%, respectively. Overall, our method produced 77.8% positive detections for at least 1 molecular marker. Twenty-eight (22.2%) were negative for expression of all markers, 39 (31.2%) were positive for expression of 1 marker, 42 (33.6%) were positive for expression of 2 markers, and 17 (13.6%) were positive for expression of all 3 markers. Detection of CK19 mRNA expression positively correlated with LC stage and distant metastases. PTHrP mRNA detection correlated positively with LC stage, presence of bone metastasis, and squamous cell carcinoma, and LUNX mRNA detection correlated with lymph node involvement. Combined detection of 2 or 3 markers was significantly correlated with metastatic disease, and negative detection of all 3 molecular markers was correlated with early stage nonmetastatic disease.

CONCLUSION

Multiple PCR-based detection of CK19, PTHrP, and LUNX mRNA expression provides useful information for disease stage and dissemination in LC patients.