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

Circulating tumor cell-derived preclinical models: current status and future perspectives

Despite the advancements made in the diagnosis and treatment of cancer, the stages associated with metastasis remain largely incurable and represent the primary cause of cancer-related deaths. The dissemination of cancer is facilitated by circulating tumor cells (CTCs), which originate from the primary tumor or metastatic sites and enter the bloodstream, subsequently spreading to distant parts of the body. CTCs have garnered significant attention in research due to their accessibility in peripheral blood, despite their low abundance. They are being extensively studied to gain a deeper understanding of the mechanisms underlying cancer dissemination and to identify effective therapeutic strategies for advanced stages of the disease. Therefore, substantial efforts have been directed towards establishing and characterizing relevant experimental models derived from CTCs, aiming to provide relevant tools for research. In this review, we provide an overview of recent progress in the establishment of preclinical CTC-derived models, such as CTC-derived xenografts (CDX) and cell cultures, which show promise for the study of CTCs. We discuss the advantages and limitations of these models and conclude by summarizing the potential future use of CTCs and CTC-derived models in cancer treatment decisions and their utility as precision medicine tools.

Combining Solid and Liquid Biopsy for Therapy Monitoring in Esophageal Cancer

Esophageal cancer (EC) has one of the highest mortality rates among cancers, making it imperative that therapies are optimized and dynamically adapted to individuals. In this regard, liquid biopsy is an increasingly important method for residual disease monitoring. However, conflicting detection rates (14% versus 60%) and varying cell-free circulating tumor DNA (ctDNA) levels (0.07% versus 0.5%) have been observed in previous studies. Here, we aim to resolve this discrepancy. For 19 EC patients, a complete set of cell-free DNA (cfDNA), formalin-fixed paraffin-embedded tumor tissue (TT) DNA and leukocyte DNA was sequenced (139 libraries). cfDNA was examined in biological duplicates and/or longitudinally, and TT DNA was examined in technical duplicates. In baseline cfDNA, mutations were detected in 12 out of 19 patients (63%); the median ctDNA level was 0.4%. Longitudinal ctDNA changes were consistent with clinical presentation. Considerable mutational diversity was observed in TT, with fewer mutations in cfDNA. The most recurrently mutated genes in TT were TP53, SMAD4, TSHZ3, and SETBP1, with SETBP1 being reported for the first time. ctDNA in blood can be used for therapy monitoring of EC patients. However, a combination of solid and liquid samples should be used to help guide individualized EC therapy.

Endovascular image-guided sampling of tumor-draining veins provides an enriched source of oncological biomarkers

Introduction

Circulating tumor-derived biomarkers can potentially impact cancer management throughout the continuum of care. This small exploratory study aimed to assess the relative levels of such biomarkers in the tumor-draining vascular beds in patients with solid tumors compared to levels in their peripheral veins.

Methods

Using an endovascular image-guided approach, we obtained blood samples from peripheral veins and other vascular compartments–including the most proximal venous drainage from solid tumors–from a set of nine oncology patients with various primary and metastatic malignancies. We then interrogated these samples for a panel of oncological biomarkers, including circulating tumor cells (CTCs), exosome-derived microRNAs (miRNAs), circulating tumor DNA (ctDNA) mutations, and certain cancer-related proteins/biochemical markers.

Results

We found substantially higher levels of CTCs, certain miRNAs, and specific ctDNA mutations in samples from vascular beds closer to the tumor compared with those from peripheral veins and also noted that some of these signals were altered by treatment procedures.

Discussion

Our results indicate that tumor-proximal venous samples are highly enriched for some oncological biomarkers and may allow for more robust molecular analysis than peripheral vein samples.

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.

Prognostic Role of Circulating Tumor Cells in the Pulmonary Vein, Peripheral Blood, and Bone Marrow in Resectable Non-Small Cell Lung Cancer

Background

Studies of the prognostic role of circulating tumor cells (CTCs) in early-stage non-small cell lung cancer (NSCLC) are still limited. This study investigated the prognostic power of CTCs from the pulmonary vein (PV), peripheral blood (PB), and bone marrow (BM) for postoperative recurrence in patients who underwent curative resection for NSCLC.

Methods

Forty patients who underwent curative resection for NSCLC were enrolled. Before resection, 10-mL samples were obtained of PB from the radial artery, blood from the PV of the lobe containing the tumor, and BM aspirates from the rib. A microfabricated filter was used for CTC enrichment, and immunofluorescence staining was used to identify CTCs.

Results

The pathologic stage was stage I in 8 patients (20%), II in 15 (38%), III in 14 (35%), and IV in 3 (8%). The median number of PB-, PV-, and BM-CTCs was 4, 4, and 5, respectively. A time-dependent receiver operating characteristic curve analysis showed that PB-CTCs had excellent predictive value for recurrence-free survival (RFS), with the highest area under the curve at each time point (first, second, and third quartiles of RFS). In a multivariate Cox proportional hazard regression model, PB-CTCs were an independent risk factor for recurrence (hazard ratio, 10.580; 95% confidence interval, 1.637–68.388; p<0.013).

Conclusion

The presence of ≥4 PB-CTCs was an independent poor prognostic factor for RFS, and PV-CTCs and PB-CTCs had a positive linear correlation in patients with recurrence.

Circulating Tumor Cells and the Non-Touch Isolation Technique in Surgery for Non-Small-Cell Lung Cancer

Circulating tumor cells (CTCs) are dislodged from the primary tumor into the bloodstream, travel within the bloodstream to distant organs, and finally extravasate and proliferate as epithelial metastatic deposits. The relationship between the existence of CTCs and tumor prognosis has been demonstrated by many researchers. In surgery for malignancies, the surgical manipulation of tumors and tissues around the tumor may lead to the release of CTCs into the bloodstream. The non-touch isolation technique (NTIT) has been advocated to prevent the release of CTCs during surgery. The concept of NTIT is the prevention of intraoperative increment of CTCs from the primary tumor by the early blockade of outflow vessels, and ‘pulmonary vein (PV)-first lobectomy’ during surgery for non-small-cell lung cancer (NSCLC) corresponds to this technique. The concept of PV-first lobectomy is well known among thoracic surgeons, but evidence of its efficacy for preventing the increase of intra- and postoperative CTCs and for improving postoperative prognosis is still uncertain. Our study summarizes evidence regarding the relationship between NTIT and CTCs in NSCLC and suggests the need for further research on CTCs and CTC-detecting modalities.

Endoscopic Ultrasound-Guided Acquisition of Portal Venous Circulating Tumor Cells as a Potential Diagnostic and Prognostic Tool for Pancreatic Cancer

Background

Circulating tumor cells (CTCs) were a promising liquid biopsy for pancreatic cancer (PC) but circulate in low counts in peripheral blood. We evaluated the diagnostic and prognostic values of portal vein (PoV) CTCs in PC patients.

Methods

PoV was aspirated under EUS guidance from 40 patients with suspected pancreaticobiliary cancers. Epithelial–mesenchymal-transition-related subtypes of CTCs were identified via immunofluorescence using EpCAM and Twist antibodies. The diagnostic and prognostic performance of PoV CTCs was investigated by receiver-operating characteristic (AUC) curve and Kaplan–Meier survival analysis.

Results

In total, 40 patients including 31 with PC, 4 with non-pancreatic periampullary cancer and 5 with benign pancreatic diseases (BPD) were enrolled. CTCs were detected more in PoV compared with peripheral blood. PoV CTC numbers in BPD patients were lower than in PC patients. The number of PoV CTCs, especially mesenchymal-CTCs (M-CTCs), was positively correlated with the tumor burden, instead of epithelial-CTCs (E-CTCs). The combination of PoV CTC numbers and CA19-9 demonstrated better diagnostic efficiency (AUC value 0.987) than either alone in differentiating PC with BPD. Moreover, the diagnostic efficacy of PoV CTCs and M-CTCs were obviously better than that of E-CTCs and CA19-9 in distinguishing early and late stage PC. Lastly, high PoV CTC and M-CTC numbers were both associated with shorter overall survival.

Conclusion

Acquisition of the PoV samples in PC patients via EUS-guided procedures has been proved safe and feasible. PoV CTCs, especially M-CTCs, have great potentials in diagnosing and predicting the prognosis of PC, especially in combination with CA19-9.

Collective metastasis: coordinating the multicellular voyage

The metastatic process is arduous. Cancer cells must escape the confines of the primary tumor, make their way into and travel through the circulation, then survive and proliferate in unfavorable microenvironments. A key question is how cancer cells overcome these multiple barriers to orchestrate distant organ colonization. Accumulating evidence in human patients and animal models supports the hypothesis that clusters of tumor cells can complete the entire metastatic journey in a process referred to as collective metastasis. Here we highlight recent studies unraveling how multicellular coordination, via both physical and biochemical coupling of cells, induces cooperative properties advantageous for the completion of metastasis. We discuss conceptual challenges and unique mechanisms arising from collective dissemination that are distinct from single cell-based metastasis. Finally, we consider how the dissection of molecular transitions regulating collective metastasis could offer potential insight into cancer therapy.

Early Dissemination of Circulating Tumor Cells: Biological and Clinical Insights

Circulating tumor cells (CTCs) play a causal role in the development of metastasis, the major cause of cancer-associated mortality worldwide. In the past decade, the development of powerful cellular and molecular technologies has led to a better understanding of the molecular characteristics and timing of dissemination of CTCs during cancer progression. For instance, genotypic and phenotypic characterization of CTCs, at the single cell level, has shown that CTCs are heterogenous, disseminate early and could represent only a minor subpopulation of the primary tumor responsible for disease relapse. While the impact of molecular profiling of CTCs has not yet been translated to the clinic, CTC enumeration has been widely used as a prognostic biomarker to monitor treatment response and to predict disease relapse. However, previous studies have revealed a major challenge: the low abundance of CTCs in the bloodstream of patients with cancer, especially in early stage disease where the identification and characterization of subsequently "lethal" cells has potentially the greatest clinical relevance. The CTC field is rapidly evolving with development of new technologies to improve the sensitivity of CTC detection, enumeration, isolation, and molecular profiling. Here we examine the technical and analytical validity of CTC technologies, we summarize current data on the biology of CTCs that disseminate early and review CTC-based clinical applications.

Microtechnology-enabled filtration-based liquid biopsy: challenges and practical considerations

Liquid biopsy, an important enabling technology for early diagnosis and dynamic monitoring of cancer, has drawn extensive attention in the past decade. With the rapid developments of microtechnology, it has been possible to manipulate cells at the single-cell level, which dramatically improves the liquid biopsy capability. As the microtechnology-enabled liquid biopsy matures from proof-of-concept demonstrations towards practical applications, a main challenge it is facing now is to process clinical samples which are usually of a large volume while containing very rare targeted cells in complex backgrounds. Therefore, a high-throughput liquid biopsy which is capable of processing liquid samples with a large volume in a reasonable time along with a high recovery rate of rare targeted cells from complex clinical liquids is in high demand. Moreover, the purity, viability and release feasibility of recovered targeted cells are the other three key impact factors requiring careful considerations. To date, among the developed techniques, micropore-type filtration has been acknowledged as the most promising solution to address the aforementioned challenges in practical applications. However, the presently reported studies about micropore-type filtration are mostly based on trial and error for device designs aiming at different cancer types, which requires lots of efforts. Therefore, there is an urgent need to investigate and elaborate the fundamental theories of micropore-type filtration and key features that influence the working performances in the liquid biopsy of real clinical samples to promote the application efficacy in practical applications. In this review, the state of the art of microtechnology-enabled filtration is systematically and comprehensively summarized. Four key features of the filtration, including throughput, purity, viability and release feasibility of the captured targeted cells, are elaborated to provide the guidelines for filter designs. The recent progress in the filtration mode modulation and sample standardization to improve the filtration performance of real clinical samples is also discussed. Finally, this review concludes with prospective views for future developments of filtration-based liquid biopsy to promote its application efficacy in clinical practice.

Portal Venous Circulating Tumor Cells Undergoing Epithelial-Mesenchymal Transition Exhibit Distinct Clinical Significance in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Much importance is attached to the clinical application value of circulating tumor cells (CTCs), meanwhile tumor-proximal CTCs detection has interested researchers for its unique advantage. This research mainly discusses the correlation of portal venous (PoV) CTCs counts in different epithelial-mesenchymal transition status with clinicopathologic parameters and postoperative prognosis in resectable pancreatic ductal adenocarcinoma patients (PDAC).

METHODS

PDAC patients (n=60) who received radical resection were enrolled in this research. PoV samples from all patients and peripheral venous (PV) samples from 32 patients among them were collected to verify spatial heterogeneity of CTCs distribution, and explore their correlation with clinicopathologic parameters and clinical prognosis.

RESULTS

CTCs detectable rate and each phenotype count of PoV were higher than those of PV. Patients with recurrence had higher PV and PoV epithelial CTCs (E-CTCs) counts than recurrence-free patients (P<0.05). Some unfavourable clinicopathologic parameters were closely related to higher PoV CTCs counts. Multivariate regression analysis demonstrated that PoV mesenchymal CTC (M-CTC)s≥1/5 ml was an independent risk factor for metastasis free survival (MFS) (P=0.003) and overall survival (OS) (P=0.043).

CONCLUSIONS

Our research demonstrated that portal venous was a preferable vessel for CTC test, and patients with PoV M-CTC≥1/5 ml had shorter MFS and OS time in resectable PDAC patients. PoV CTC phenotype detection has the potential to be a reliable and accurate tool to identify resectable PDAC patients with high tendency of postoperative metastasis for better stratified management.

Wedge Resection of Tumor Before Lobectomy for Lung Cancer Could Be a No-touch Isolation Technique

BACKGROUND/AIM

Circulating tumor cells (CTCs) can be a surrogate biomarker of prospective prognosis. Surgical manipulation can promote the dissemination of CTCs. Prognosis improvement is expected with the no-touch isolation technique (NTIT), preventing surgical manipulation. The Wedge resection of the tumor site before lobectomy could prevent surgical manipulation during lobectomy for non-small cell lung cancer (NSCLC) and reduce the shedding of tumor cells, similar to a NTIT. This study aimed to evaluate the effect of wedge resection technique.

PATIENTS AND METHODS

A total of 624 resected NSCLC patients were retrospectively analyzed. Patients were divided in two groups: Wedge and Non-Wedge. Overall survival (OS) curves were plotted using the Kaplan-Meier method.

RESULTS

The 5-year OS rates were 89.9% and 84.0% in the Wedge and Non-Wedge groups, respectively (p=0.033).

CONCLUSION

The OS in the Wedge group was significantly better than that in the Non-Wedge group. Wedge resection technique for NSCLC may be a NTIT.

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.

Relevance of CTC Clusters in Breast Cancer Metastasis

Metastasis is the major cause of mortality in patients with breast cancer; however, the mechanisms of tumor cell dissemination and metastasis formation are not well established yet. The study of circulating tumour cells (CTCs), the metastatic precursors of distant disease, may help in this search. CTCs can be found in the blood of cancer patients as single cells or as tumor cell aggregates, known as CTC clusters. CTC clusters have differential biological features such as an enhanced survival and metastatic potential, and they hold great promises for the evaluation of prognosis, diagnosis and therapy of the metastatic cancer. The analysis of CTC clusters offers new insights into the mechanism of metastasis and can guide towards the development of new diagnostic and therapeutic strategies to suppress cancer metastasis. This has become possible thanks to the development of improved technologies for detection of CTCs and CTC clusters. However, more efficient methods are needed in order to address important questions regarding the metastatic potential of CTC and future clinical applications. In this chapter, we explore the current knowledge on the role of CTC clusters in breast cancer metastasis, their origin, metastatic advantages and clinical importance.

Liquid biopsy, a paradigm shift in oncology: what interventional radiologists should know

The acquisition of adequate tumor sample is required to verify primary tumor type and specific biomarkers and to assess response to therapy. Historically, invasive surgical procedures were the standard methods to acquire tumor samples until advancements in imaging and minimally invasive equipment facilitated the paradigm shift image-guided biopsy. Image-guided biopsy has improved sampling yield and minimized risk to the patient; however, there are still limitations, such as its invasive nature and its consequent limitations to longitudinal tumor monitoring. The next paradigm shift in sampling technique will need to address these issues to provide a more reliable and less invasive technique. Recently, liquid biopsy (LB) has emerged as a non-invasive alternative to tissue sampling. This technique relies on direct sampling of blood or other bodily fluids in contact with the tumor in order to collect circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), and circulating RNAs-in particular microRNA (miRNAs). Clinical applications of LB involve different steps of cancer patient management including screening, detection of disease recurrence, and evaluation of acquired resistance. With any paradigm shift, old techniques are often relegated to a secondary option. Although image-guided biopsies may appear as a passive spectator on the rapid advancement of LB, the two techniques may well be codependent. Interventional radiology may be integral to directly sample the liquid surrounding or draining from the tumor. In addition, LB may help to correctly select the patients for image-guided loco-regional treatments, to determine its treatment endpoint, and to early detect recurrence. KEY POINTS: • Liquid biopsy is a novel technology with potential high impact in the management of patients undergoing image-guided procedures. • Interventional radiology procedures may increase liquid biopsy sensitivity through direct fluid sampling. • Liquid biopsy techniques may provide a venue for improving patients' selection and enhance outcomes of interventional loco-regional therapies performed by interventional radiologists.

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.

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 cells and circulating tumor DNA before and after mammographic breast compression in a cohort of breast cancer patients scheduled for neoadjuvant treatment

PURPOSE

It is not known if mammographic breast compression of a primary tumor causes shedding of tumor cells into the circulatory system. Little is known about how the detection of circulating biomarkers such as circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) is affected by breast compression intervention.

METHODS

CTCs and ctDNA were analyzed in blood samples collected before and after breast compression in 31 patients with primary breast cancer scheduled for neoadjuvant therapy. All patients had a central venous access to allow administration of intravenous neoadjuvant chemotherapy, which enabled blood collection from superior vena cava, draining the breasts, in addition to sampling from a peripheral vein.

RESULTS

CTC and ctDNA positivity was seen in 26% and 65% of the patients, respectively. There was a significant increase of ctDNA after breast compression in central blood (p = 0.01), not observed in peripheral testing. No increase related with breast compression was observed for CTC. ctDNA positivity was associated with older age (p = 0.05), and ctDNA increase after breast compression was associated with high Ki67 proliferating tumors (p = 0.04). CTCs were more abundant in central compared to peripheral blood samples (p = 0.04).

CONCLUSIONS

There was no significant release of CTCs after mammographic breast compression but more CTCs were present in central compared to peripheral blood. No significant difference between central and peripheral levels of ctDNA was observed. The small average increase in ctDNA after breast compression is unlikely to be clinically relevant. The results give support for mammography as a safe procedure from the point of view of CTC and ctDNA shedding to the blood circulation. The results may have implications for the standardization of sampling procedures for circulating tumor markers.

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.

Exosome Analysis in Tumor-Draining Pulmonary Vein Identifies NSCLC Patients with Higher Risk of Relapse after Curative Surgery

Since tumor-draining pulmonary vein blood (PV) is enriched in tumor-secreted products, we hypothesized that it would also be enriched in tumor-derived exosomes, which would be important in the metastasis process. We characterized exosomes from PV of 61 resected non-small cell lung cancer (NSCLC) patients to evaluate its potential as relapse biomarkers. Exosomes were characterized using transmission electron microscopy, western blot and nanoparticle tracking analysis and we examined time to relapse (TTR) and overall survival (OS). Differences between PV and peripheral vein were found. PV was enriched in smaller exosomes than the paired peripheral vein (p = 0.01). Moreover, PV exosome size mode was able to identify relapsed patients (Area under the curve [AUC] = 0.781; 95%CI: 0.6641⁻0.8978), in whom exosome size was smaller (<112 nm; p < 0.001). The combination of PV exosome size and N (lymph node involvement) showed an AUC of 0.89 (95%CI: 0.80⁻0.97). Moreover, smaller PV exosome size was associated with shorter TTR (28.3 months vs. not reached, p < 0.001) and OS (43.9 months vs. not reached, p = 0.009). Multivariate analyses identified PV exosome size and stage as independent prognostic markers for TTR and OS. PV exosome size is a promising relapse biomarker after surgery that can add valuable information to clinical variables.

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.

Clinical significance of circulating tumor cells from lung cancer patients using microfluidic chip

Circulating tumor cells (CTCs) exist in the peripheral blood and have an important role in the disease development, tumor metastasis and clinical surveillance, especially in the process of metastasis. However, the technology of detecting CTCs still had a large challenge since they were rare in the peripheral blood. Here, we developed a size-based microfluidic chip, which contained array and filter channel array that could enrich CTCs from blood samples more quickly and conveniently. Combined with clinical specimen, we analyzed CTCs in 200 lung cancer patients by this microfluidic chip. The microfluidic device has high specificity and sensitivity in detecting CTCs (86.0% sensitivity and 98% specificity). Furthermore, the number of CTCs showed a increasing trend according to the stage of the disease (the mean number of I stage 5.0 ± 5.121 versus II stage 8.731 ± 6.36 versus III stage 16.81 ± 9.556 versus IV stage 28.72 ± 17.39 cells/mL, P < 0.05). The number of CTCs was concurrent with the condition of pathological type and metastasis patients. Compared to conventional markers like CEA, CY211, SCC, CTCs showed a higher positive rate in diagnosed patients. The advanced microfluidic device could capture tumor cells without reliance on cell surface expression markers and provide a fast, convenient, economical method in detecting CTCs, thereby offering potential to design effective and individualized cancer therapies.

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.

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.

Circulating tumor cells and CDX models as a tool for preclinical drug development

Lung cancers are the main cause of cancer-related deaths worldwide. Efforts placed to improve the survival of lung cancer patients and untangle the complexity of this disease, have resulted in the generation of hundreds of lung cancer cell lines and several genetically engineered mouse models (GEMMs). Although these research tools have extended our knowledge of lung cancer, improvement in the clinical care of lung cancer patients have been limited overall, with measured optimism regarding initial responses to targeted therapies in stratified subgroups of patients. Patient-derived xenograft (PDX) models are beginning to assist 'personalized therapy' approaches particularly in non-small cell lung cancer (NSCLC) however biopsies of lung cancers to generate PDXs are not without challenges and risks to the patient. Liquid biopsies, on the other hand, are a rapid and non-invasive procedure allowing the collection of circulating tumor cells (CTCs) with a single 10 mL blood draw. These CTCs recapitulate the molecular heterogeneity of the corresponding tumors and, therefore, can be used as surrogates to study tumor biology and generate new patient-derived models. Here, we discuss the CTC-derived models that have been generated, most notably in small cell lung cancer (SCLC), highlighting challenges and opportunities related to these novel preclinical tools.

Comparison of plasma to tissue DNA mutations in surgical patients with non-small cell lung cancer

OBJECTIVE

Noninvasive liquid biopsies of circulating tumor DNA (ctDNA) can be used to assess non-small cell lung cancer (NSCLC), but previous work focused on patients with advanced-stage cancer. Thus, we evaluated the feasibility and their potential clinical application of circulating tumor DNA approached for surgical patients with NSCLC.

METHOD

Consecutive patients with suspected lung cancer who underwent curative-intent lung resection were enrolled prospectively in this study. Targeted DNA sequencing with a next-generation sequencing platform was used to identify a series of somatic mutations in matched tumor tissue DNA (tDNA) and plasma ctDNA samples. Plasma was collected before, during, and after surgery. Concordance was defined as matched tDNA and ctDNA with the same identified mutations or with no mutations.

RESULTS

In the enrolled 76 patients with lung cancer who were included, 31 had concordant mutations and 21 had no mutation in both ctDNA and tDNA, yielding an overall concordance of 68.4%. ctDNA samples obtained before and during surgery had the same mutations with a low variance in mutation frequency (1.2%) that was reduced to an average of 0.28% after surgery (P < .001). More patients were positive as assayed by ctDNA (48; 63.2%) than with serum tumor protein markers (36; 49.3%). The area under the curve was greater in ctDNA (0.887, 95% confidence interval [CI], 0.788-0.986) than for the 2 prediction models (0.803, 95% CI, 0.647-0.959; 0.69, 95% CI, 0.512-0.869) for estimating malignancy of solitary pulmonary nodules.

CONCLUSION

ctDNA mutation analysis for stage I-III surgical patients with NSCLC is feasible. More studies are needed to investigate its clinical application.

Detection of Circulating Tumor Cells and Circulating Tumor Microemboli in Gastric Cancer

PURPOSE: Gastric cancer studies indicated a potential correlation between circulating tumor cells (CTCs) in peripheral blood and tumor relapse/metastasis. The prevalence and significance of circulating tumor microemboli (CTM) in gastric cancer remain unknown. We investigated the prevalence and prognostic value of CTCs and CTM for progression-free survival (PFS) and overall survival (OS) in gastric cancer patients. METHODS:Eighty-one gastric cancer patients consented to provide 5 ml of peripheral blood before systematic therapy. CTCs and CTM were isolated using isolation by size of epithelial tumor cells and characterized by cytopathologists. For 41 stage IV gastric cancer patients, CTM was investigated as a potential biomarker to predict prognosis. RESULTS:CTCs were detected in 51 patients; the average count was 1.81. In clinical stage I, II, III, and IV patients, the average CTC counts were 1.40, 0.67, 1.24, and 2.71, respectively. CTM were detected in 3 of 33 clinical stage I to IIIb patients, at an average of 0.12 (0-2). CTM were detected in 13 of 53 clinical stage IIIc to IV patients, at an average of 1.26 (0-22). In stage IV patients, CTM positivity correlated with the CA125 level. PFS and OS in CTM-positive patients were significantly lower than in CTM-negative patients (P < .001). CTM positivity was an independent factor for determining the PFS (P = .016) and OS (P = .003) of stage IV patients in multivariate analysis. Using markers of the epithelial-mesenchymal transition, single CTCs were divided into three phenotypes including epithelial CTCs, biphenotypic epithelial/mesenchymal CTCs, and mesenchymal CTCs. For CTM, CK−/Vimentin+/CD45− and CK+/Vimentin+/CD45− phenotypes were observed, but the CK+/Vimentin−/CD45− CTM phenotype was not. CA125 was detected in gastric cancer cell lines BGC823 and MGC803. CONCLUSIONS: In stage IV patients, CTM positivity was correlated with serum CA125 level. CTM were an independent predictor of shorter PFS and OS in stage IV patients. Thus, CTM detection may be a useful tool to predict prognosis in stage IV patients.

Screening and Early Detection of Lung Cancer

OBJECTIVE

To review current risk factors for lung cancer, identify screening and early detection guidelines while describing new approaches that use genomic technologies.

DATA SOURCES

Published scientific literature, clinical literature, and published lung cancer screening guidelines from the United States and Canada.

CONCLUSION

Nurses are caring for lung cancer patients who, historically, do not live for long periods after diagnosis. Research is revealing promising screening methodologies that can detect lung cancer 1 to 4 years earlier than the current approaches.

IMPLICATIONS FOR NURSING PRACTICE

Current knowledge about screening for lung cancer is a vital tool for nurses working with persons at high risk for this potentially aggressive and life-threatening malignancy. While old methods remain the standard of care, new detection methods use a variety of genomic-based technologies. These developing approaches emphasize the need for nurses at all levels of practice to have a working knowledge of genetics to educate patients and conference with colleagues.

Circulating tumor cell clusters: What we know and what we expect (Review)

The major cause of cancer-associated mortality is tumor metastasis, a disease that is far from understood. Many studies have observed circulating tumor cells (CTCs) in patients' circulation systems, and a few latest investigations showed that CTC clusters have a potentially high capacity of metastasis. The capture and analysis of CTC clusters offer new insights into tumor metastasis and can facilitate the development of cancer treatments. We reviewed the research history of the CTC clusters, as well as the technologies used for detecting and isolating CTC clusters. In addition, we discuss the characteristics of CTC clusters and their roles in tumor dissemination. Clinical relevance of CTC clusters was also implicated in currently limited data. Moving forward, the next frontier in this field is to develop more efficient capture methods and decipher conundrums of characterization of CTC clusters. This will ultimately identify the clinical value of CTC clusters as a biomarker and therapeutic target.

The Role of Pulmonary Veins in Cancer Progression from a Computed Tomography Viewpoint

Background. We studied the role of pulmonary veins in cancer progression using computed tomography (CT) scans. Methods. We obtained data from 260 patients with pulmonary vein obstruction syndrome (PVOS). We used CT scans to investigate pulmonary lesions in relation to pulmonary veins. We divided the lesions into central and peripheral lesions by their anatomical location: in the lung parenchymal tissue or pulmonary vein; in the superior or inferior pulmonary vein; and by unilateral or bilateral presence in the lungs. Results. Of the 260 PVOS patients, 226 (87%) had central lesions, 231 (89%) had peripheral lesions, and 190 (75%) had mixed central and peripheral lesions. Among the 226 central lesions, 93% had lesions within the superior pulmonary vein, either bilaterally or unilaterally. Among the 231 peripheral lesions, 65% involved bilateral lungs, 70% involved lesions within the inferior pulmonary veins, and 23% had obvious metastatic extensions into the left atrium. All patients exhibited nodules within their pulmonary veins. The predeath status included respiratory failure (40%) and loss of consciousness (60%). Conclusion. CT scans play an important role in following tumor progression within pulmonary veins. Besides respiratory distress, PVOS cancer cells entering centrally can result in cardiac and cerebral events and loss of consciousness or can metastasize peripherally from the pulmonary veins to the lungs.

Perioperative circulating tumor cell detection: Current perspectives

Primary cancer resections and in selected cases surgical metastasectomies significantly improve survival, however many patients develop recurrences. Circulating tumor cells (CTCs) function as an independent marker that could be used in the prognostication of different cancers. Sampling of blood and bone marrow compartments during cancer resections is a unique opportunity to increase individual tumor cell capture efficiency. This review will address the diagnostic and therapeutic potentials of perioperative tumor isolation and highlight the focus of future studies on characterization of single disseminated cancer cells to identify targets for molecular therapy and immune escape mechanisms.