Mesenchymal circulating tumor cells (CTCs) and OCT4 mRNA expression in CTCs for prognosis prediction in patients with non-small-cell lung cancer

Octamer-binding transcription factor 4-positive circulating tumor cell predicts worse treatment response and survival in advanced cholangiocarcinoma patients who receive immune checkpoint inhibitors treatment

BACKGROUND

Octamer-binding transcription factor 4-positive circulating tumor cell (OCT4+CTC) exhibits high stemness and invasive potential, which may influence the efficacy of immune checkpoint inhibitors (ICI). This study aimed to assess the prognostic role of OCT4+CTC in advanced cholangiocarcinoma (CCA) patients who received ICI treatment.

METHODS

In total, 40 advanced CCA patients who received ICI treatment were included, and CTC and OCT4 counts were detected via a Canpatrol system and an RNA in situ hybridization method before ICI treatment. Patients were subsequently divided into none CTC, OCT4-CTC, and OCT4+CTC groups. Patients were followed up for a median of 10.4 months.

RESULTS

The percentages of patients in none CTC, OCT4-CTC, and OCT4+CTC groups were 25.0%, 30.0%, and 45.0%, respectively. The proportion of patients with lymph node metastasis was highest in OCT4+CTC group, followed by none CTC group, and lowest in OCT4-CTC group (P = 0.025). The objective response rate (ORR) was lowest in OCT4+CTC group, moderate in OCT4-CTC group, and highest in none CTC group (P = 0.009), while disease control rate was not different among three groups (P = 0.293). In addition, progression-free survival (PFS) (P < 0.001) and overall survival (OS) (P = 0.001) were shorter in the OCT4+CTC group than in none CTC & OCT4-CTC group. Moreover, OCT4+CTC (versus none CTC) was independently linked with poorer PFS [hazard ratio (HR) = 6.752, P = 0.001] and OS (HR = 6.674, P = 0.003) in advanced CCA patients.

CONCLUSION

OCT4+CTC relates to lymph node metastasis and shows a good predictive value for poor treatment response and survival in advanced CCA patients who receive ICI treatment.

OCT4‑positive circulating tumor cells may predict a poor prognosis in patients with metastatic castration‑resistant prostate cancer treated with abiraterone plus prednisone therapy

Octamer-binding transcription factor 4 (OCT4) and circulating tumor cells (CTCs) are key factors associated with tumor metastasis and drug resistance in cancer. The present prospective study aimed to investigate the prevalence of OCT4-positive (OCT4+) CTCs and the potential association with the clinical features and survival of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone + prednisone. In total, 70 patients with mCRPC treated with abiraterone + prednisone were enrolled in the present study and peripheral blood samples were collected prior to treatment initiation to determine CTC count via a Canpatrol system. RNA in situ hybridization was performed for OCT4+ CTC quantification. Lactate dehydrogenase (LDH) was detected by automatic biochemical analyzer (AU54000, OLYMPUS). Results demonstrated that 34 (48.6%), 21 (30.0%) and 15 (21.4%) patients harbored OCT4+ (CTC+/OCT4+) or OCT4-negative CTCs (CTC+/OCT4-) or were CTC-negative (CTC-), respectively. Notably, CTC+/OCT4+ occurrence was associated with visceral metastasis and high levels of LDH. In addition, radiographic progression-free survival [rPFS; median, 15.0, 95% confidence interval (CI), 9.6-20.4 vs. not reached vs. median, 29.5, 95% CI, 18.6-40.4 months; P=0.001] and overall survival (OS) were significantly decreased (median, 27.3, 95% CI, 20.1-34.5 vs. not reached vs. not reached; P=0.016) in CTC+/OCT4+ compared with CTC+/OCT4- and CTC- patients. Subsequently, the adjustment was performed by multivariate Cox regression models, which revealed that CTC+/OCT4+ (vs. CTC+/OCT4- or CTC-) was independently associated with decreased rPFS [hazard ratio (HR), 3.833; P<0.001] and OS (HR, 3.938; P=0.008). In conclusion, OCT4+ CTCs were highly prevalent in patients with mCRPC and associated with visceral metastasis and increased levels of LDH. Thus, the presence of OCT4+ CTCs may serve as an independent prognostic factor for patients with mCRPC treated with abiraterone + prednisone.

Advances in liquid biopsy-based markers in NSCLC

Lung cancer is the second most-frequently occurring cancer and the leading cause of cancer-associated deaths worldwide. Non-small cell lung cancer (NSCLC), the most common type of lung cancer is often diagnosed in middle or advanced stages and have poor prognosis. Diagnosis of disease at an early stage is a key factor for improving prognosis and reducing mortality, whereas, the currently used diagnostic tools are not sufficiently sensitive for early-stage NSCLC. The emergence of liquid biopsy has ushered in a new era of diagnosis and management of cancers, including NSCLC, since analysis of circulating tumor-derived components, such as cell-free DNA (cfDNA), circulating tumor cells (CTCs), cell-free RNAs (cfRNAs), exosomes, tumor-educated platelets (TEPs), proteins, and metabolites in blood or other biofluids can enable early cancer detection, treatment selection, therapy monitoring and prognosis assessment. There have been great advances in liquid biopsy of NSCLC in the past few years. Hence, this chapter introduces the latest advances on the clinical application of cfDNA, CTCs, cfRNAs and exosomes, with a particular focus on their application as early markers in the diagnosis, treatment and prognosis of NSCLC.

Mesenchymal circulating tumor cells and Ki67: their mutual correlation and prognostic implications in hepatocellular carcinoma

BACKGROUND

Mesenchymal circulating tumor cells (M-CTCs) may be related to tumor progression, and Ki67 expression is known to be involved in tumor proliferation. The aim of the present study was to explore the relationship between M-CTCs and Ki67 in hepatocellular carcinoma (HCC) and their ability to predict prognosis.

METHODS

Peripheral blood samples were obtained from 105 HCC patients before radical surgery. CTCs were isolated using CanPatrol enrichment and classified via in situ hybridization. Ki67 expression in HCC tissue was assessed through immunohistochemistry. Potential relationships of M-CTC, Ki67 with clinicopathological factors and prognosis were evaluated. Overall survival (OS) was analyzed using the Kaplan-Meier method and Cox regression. The prognostic efficacy of M-CTC, Ki67 and both together (M-CTC + Ki67) was assessed in terms of time-dependent receiver operating characteristic (ROC) curves and Harrell's concordance index.

RESULTS

Of the 105 patients, 50 were positive for M-CTCs (count ≥ 1 per 5 mL) and 39 showed high Ki67 expression (≥ 50% tumor cells were Ki67-positive). The presence of M-CTC was significantly associated with alpha-fetoprotein (AFP) ≥ 400 ng/mL (P = 0.007), tumor size ≥ 5 cm (P = 0.023), multiple tumors (P < 0.001), poorly differentiated tumors (P = 0.003), incomplete tumor capsule (P < 0.001), Barcelona Clinic liver cancer (BCLC) stage B or C (P < 0.001), microvascular invasion (MVI) (P = 0.05) and portal vein tumor thrombosis (PVTT) (P = 0.006). High Ki67 expression correlated with AFP ≥ 400 ng/mL (P = 0.015), tumor size ≥ 5 cm (P = 0.012), incomplete tumor capsule (P < 0.001), MVI (P = 0.001), PVTT (P = 0.003), advanced BCLC stage (P = 0.01), and vessel carcinoma embolus (VCE) (P = 0.001). M-CTC positively correlated with Ki67. Patients positive for M-CTCs had a significantly shorter OS than patients negative for them. Similarly, high Ki67 expression was associated with a significantly lower OS. The high-risk group (positive for M-CTCs and high Ki67 expression) had worse OS than the other groups (P < 0.0001). Uni- and multivariate analyses showed that OS was independently predicted by M-CTC [hazard ratio (HR) 1.115; P < 0.001], Ki67 (HR 1.666; P = 0.046) and the combination of both (HR 2.885; P = 0.008). Based on ROC curves and the concordance index, the combination of M-CTC and Ki67 was superior to either parameter alone for predicting the OS of HCC patients.

CONCLUSIONS

The presence of M-CTC correlates with high Ki67 expression in HCC patients, and both factors are associated with poor prognosis. Furthermore, the combination of M-CTC and Ki67 is a useful prognostic indicator for predicting OS in patients with HCC after hepatectomy, performing better than either parameter on its own.

Presence of CD133-positive circulating tumor cells predicts worse progression-free survival in patients with metastatic castration-sensitive prostate cancer

Objective

To investigate the clinical significance of the expression of the stemness marker CD133 in circulating tumor cells of newly diagnosed metastatic castration‐sensitive prostate cancer patients.

Methods

For this study, 104 metastatic castration‐sensitive prostate cancer patients treated at the Fudan University Shanghai Cancer Center from September 2015 to February 2017 were considered. After enrollment, the patients received androgen deprivation therapy (bicalutamide + goserelin). Circulating tumor cells were isolated and identified using the CanPatrol system, which can identify not only traditional epithelial markers but also mesenchymal markers in cells that have undergone epithelial mesenchymal transition. CD133 was used to characterize the circulating tumor cells. The primary endpoint of this research was to evaluate progression to castration resistance.

Results

Among the 104 patients enrolled, 89 patients were circulating tumor cell positive at baseline, and the median circulating tumor cell count was four. The median follow‐up was 24 months, and at the end of follow‐up, the proportion of patients who progressed to castration‐resistant prostate cancer in the CTC+CD133+ group was 93.3%, which was significantly higher than that of the circulating tumor cell negative group (73.3%) and the CTC+CD133− group (75.0%), with P = 0.043. After follow‐up, progression‐free survival for CTC+CD133+, CTC+CD133−, and circulating tumor cell patients was 10.0, 13.0, and 14.0 months, respectively, with P = 0.022. Univariate and multivariate analyses also confirmed that the characterization of circulating tumor cells using CD133 can independently predict progression‐free survival in metastatic castration‐sensitive prostate cancer patients after receiving androgen deprivation therapy (P = 0.042; hazard ratio 1.396).

Conclusion

Baseline CTC+CD133+ was a poor independent prognostic factor for metastatic castration‐sensitive prostate cancer patients to progress to castration‐resistant prostate cancer after receiving androgen deprivation therapy.

Discriminating Epithelial to Mesenchymal Transition Phenotypes in Circulating Tumor Cells Isolated from Advanced Gastrointestinal Cancer Patients

Gastrointestinal (GI) cancers constitute a group of highest morbidity worldwide, with colorectal cancer (CRC) and gastric cancer being among the most frequently diagnosed. The majority of gastrointestinal cancer patients already present metastasis by the time of diagnosis, which is widely associated with cancer-related death. Accumulating evidence suggests that epithelial-to-mesenchymal transition (EMT) in cancer promotes circulating tumor cell (CTCs) formation, which ultimately drives metastasis development. These cells have emerged as a fundamental tool for cancer diagnosis and monitoring, as they reflect tumor heterogeneity and the clonal evolution of cancer in real-time. In particular, EMT phenotypes are commonly associated with therapy resistance. Thus, capturing these CTCs is expected to reveal important clinical information. However, currently available CTC isolation approaches are suboptimal and are often targeted to capture epithelial CTCs, leading to the loss of EMT or mesenchymal CTCs. Here, we describe size-based CTCs isolation using the RUBYchip™, a label-free microfluidic device, aiming to detect EMT biomarkers in CTCs from whole blood samples of GI cancer patients. We found that, for most cases, the mesenchymal phenotype was predominant, and in fact a considerable fraction of isolated CTCs did not express epithelial markers. The RUBYchip™ can overcome the limitations of label-dependent technologies and improve the identification of CTC subpopulations that may be related to different clinical outcomes.

Progress and application of circulating tumor cells in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) has the highest morbidity and mortality worldwide among malignant tumors. NSCLC is a great threat to health and well-being. Biopsy is the gold standard to diagnose lung cancer, but traditional biopsy methods cannot fully reflect the true condition of tumors. There is growing evidence that a single-point biopsy fails to reveal the complete landscape of the tumor due to intratumor heterogeneity, but it is impractical to complete multiple biopsies that are separated both spatially and temporally. Liquid biopsy heralds that a new era is coming. Circulating tumor cells (CTCs) are tumor cells that circulate in the peripheral blood after being shed from primary or metastatic tumors. CTCs constitute a considerable portion of a liquid biopsy, which contributes to the diagnosis, assessment of prognosis, and therapy of NSCLC. Herein, this review discusses the technologies for detection and enrichment of CTCs as well as clinical applications involving CTCs.

Clinical Relevance of Mesenchymal- and Stem-Associated Phenotypes in Circulating Tumor Cells Isolated from Lung Cancer Patients

Simple Summary

Lung cancer is the most frequent malignancy in the world. Most lung cancer patients are diagnosed at an advanced stage. To make matters worse, the survival of patients is very poor. Circulating tumor cells (CTCs), albeit rare, have been portrayed as essential players in the progression of lung cancer. It is definitely not easy being a CTC. First, they escape from the primary tumor, then they travel in the bloodstream, have to survive really harsh conditions, and finally, they form metastases. The adoption of epithelial-to-mesenchymal transition as well as cancer stem cell features has been suggested to allow CTCs to survive and metastasize. This review will focus on how these features can be used to estimate the prognosis of lung cancer patients.

Abstract

Lung cancer is the leading cause of cancer-related mortality globally. Among the types of lung cancer, non-small-cell lung cancer (NSCLC) is more common, while small-cell lung cancer (SCLC) is less frequent yet more aggressive. Circulating tumor cells (CTCs), albeit rare, have been portrayed as essential players in the progression of lung cancer. CTCs are considered to adopt an epithelial-to-mesenchymal transition (EMT) phenotype and characteristics of cancer stem cells (CSCs). This EMT (or partial) phenotype affords these cells the ability to escape from the primary tumor, travel into the bloodstream, and survive extremely adverse conditions, before colonizing distant foci. Acquisition of CSC features, such as self-renewal, differentiation, and migratory potential, further reflect CTCs’ invasive potential. CSCs have been identified in lung cancer, and expression of EMT markers has previously been correlated with poor clinical outcomes. Thus far, a vast majority of studies have concentrated on CTC detection and enumeration as a prognostic tools of patients’ survival or for monitoring treatment efficacy. In this review, we highlight EMT and CSC markers in CTCs and focus on the clinical significance of these phenotypes in the progression of both non-small- and small-cell lung cancer.

Non-invasive detection of epithelial mesenchymal transition phenotype and metastatic dissemination of lung cancer by liquid biopsy

The occurrence of phenotype switch from an epithelial to a mesenchymal cell state during the activation of the epithelial mesenchymal transition (EMT) program in cancer cells has been closely associated with the generation of invasive tumor cells that contribute to metastatic dissemination and treatment failure. Liquid biopsy represents an emergent non-invasive tool that may improve our understanding of the molecular events leading to cancer progression and initiating the metastatic cascade through the dynamic analysis of tumor-derived components isolated from body fluids. The present review will primarily focus on the applications of liquid biopsy in lung cancer patients for identifying EMT signature, elucidating molecular mechanisms underlying the acquisition of an invasive phenotype and detecting new targets for therapy.

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.

Evaluation of sensitivity and specificity of CanPatrol™ technology for detection of circulating tumor cells in patients with non-small cell lung cancer. BMC Pulm Med. 2020;20:274. [PMID: 33081780 DOI: 10.1186/s12890-020-01314-4]

Background

The early diagnosis of non-small cell lung cancer is of great significance to the prognosis of patients. However, traditional histopathology and imaging screening have certain limitations. Therefore, new diagnostical methods are urgently needed for the current clinical diagnosis. In this study we evaluated the sensitivity and specificity of CanPatrol™ technology for the detection of circulating tumor cells in patients with non-small cell lung cancer (NSCLC).

Methods

CTCs in the peripheral blood of 98 patients with NSCLC and 38 patients with benign pulmonary diseases were collected by the latest typing of CanPatrol™ detection technology. A 3-year follow-up was performed to observe their recurrence and metastasis. Kruskal-Wallis test was used to compare multiple groups of data, Mann-Whitney U test was used to compare data between the two groups, and ROC curve analysis was used to obtain the critical value. The COX risk regression and Kaplan-Meier survival analysis were performed in the 63 NSCLC patients who were effectively followed up.

Results

The epithelial, epithelial-mesenchymal, and total CTCs were significantly higher in NSCLC patients than that in patients with benign lung disease (P <  0.001). The mesenchymal CTCs of NSCLC patients was slightly higher than that of benign lung diseases (P = 0.013). The AUC of the ROC curve of the total CTCs was 0.837 (95% CI: 0.76-0.914), and the cut-off value corresponding to the most approximate index was 0.5 CTCs/5 ml, at which point the sensitivity was 81.6% and the specificity was 86.8%. COX regression analysis revealed that the clinical stage was correlated with patient survival (P = 0.006), while gender, age, and smoking were not (P > 0.05). After excluding the confounders of staging, surgery, and chemotherapy, Kaplan-Meier survival analysis showed that patients in stage IIIA with CTCs ≥0.5 had significantly lower DFS than those with CTCs < 0.5 (P = 0.022).

Conclusions

CTC positive can well predict the recurrence of NSCLC patients. CanPatrol™ technology has good sensitivity and specificity in detecting CTCs in peripheral blood of NSCLC patients and has a certain value for clinical prognosis evaluation.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12890-020-01314-4.

Clinical Impact of the Epithelial-Mesenchymal Transition in Lung Cancer as a Biomarker Assisting in Therapeutic Decisions

Lung cancer is one of the most common solid cancers and represents the leading cause of cancer death worldwide. Over the last decade, research on the epithelial-mesenchymal transition (EMT) in lung cancer has gained increasing attention. Here, we review clinical and histological features of non-small-cell lung cancer associated with EMT. We then aimed to establish potential clinical implications of EMT in current therapeutic options, including surgery, radiation, targeted therapy against oncogenic drivers, and immunotherapy.

Clinical Significance of Red Cell Distribution Width and Circulating Tumor Cells with an Epithelial-Mesenchymal Transition Phenotype in Lung Adenocarcinoma

Objective

To determine the prognostic value of red cell distribution width (RDW) and circulating tumor cells with epithelial–mesenchymal transition phenotype (M-CTC) in lung adenocarcinoma (LUAD).

Patients and Methods

Clinical and laboratory data of 60 patients with LUAD were collected. CTCs were isolated from their peripheral blood using the CanPatrol^TM CTC enrichment method. The indicators of RDW and neutrophil lymphocyte ratio (NLR) were calculated based on the laboratory standards.

Results

A total of 60 LUAD patients were enrolled, of which 19 (31.7%) had high RDW (>0.14) and 32 (53.3%) were positive for M-CTCs. There was no significant correlation between RDW and the clinical characteristics. M-CTC was not significantly associated with tumor size and differentiation, age, gender, tumor stage, and histological type but correlated significantly with lymphatic metastasis (P = 0.044), high NLR (>2.26, P = 0.023), and high RDW (>0.14, P = 0.036). Furthermore, the M-CTC⁺ LUAD patients had a significantly poor recurrence-free survival (RFS; Log rank P =0.001, HR = 2.749, 95% CI = 1.489–5.078) and overall survival (OS; Log rank P =0.022, HR = 2.283, 95% CI = 1.128–4.622) compared to the M-CTC⁻ patients. Similarly, high RDW also correlated with worse RFS (Log rank P = 0.008, HR = 2.331, 95% CI = 1.248–4.353) and OS (Log rank P = 0.004, HR = 0.004, 95% CI = 1.398–5.525).

Conclusion

M-CTC is significantly related to RDW and NLR, and an independent prognostic factor in LUAD.

EMT-Associated Heterogeneity in Circulating Tumor Cells: Sticky Friends on the Road to Metastasis

Epithelial–mesenchymal transitions (EMTs) generate hybrid phenotypes with an enhanced ability to adapt to diverse microenvironments encountered during the metastatic spread. Accordingly, EMTs play a crucial role in the biology of circulating tumor cells (CTCs) and contribute to their heterogeneity. Here, we review major EMT-driven properties that may help hybrid Epithelial/Mesenchymal CTCs to survive in the bloodstream and accomplish early phases of metastatic colonization. We then discuss how interrogating EMT in CTCs as a companion biomarker could help refine cancer patient management, further supporting the relevance of CTCs in personalized medicine.

Differential expression of SALL4 in CTCs derived from hydatidiform moles and gestational trophoblastic neoplasms

PROBLEM

To investigate EMT phenotype and SALL4 expression of circulating tumour cells (CTCs) in patients with gestational trophoblastic neoplasm (GTN).

METHOD OF STUDY

CanPatrol CTC detection system in combination with SALL4 RNA in situ hybridization was used to investigate the profile of CTCs in different types of gestational trophoblastic disease (GTD). Circulating CTCs were phenotyped and annotated with SALL4 expression in 41 GTD patients, including 12 HM and 29 GTN, as well as 22 pregnant volunteers.

RESULTS

A positive correlation between the number of CTC and serum β-hCG concentration was found among the GTN patients. The number of E/M-CTC was positively correlated with serum β-hCG, while M-CTC was positively correlated with prognostic score. Comparison among malignant GTD, benign GTD and healthy pregnant women revealed a significant difference in the number of total CTC, E/M-CTC, and M-CTC but not in E-CTC. ROC analysis was conducted to evaluate the performance of CTC phenotypes in distinguishing GTD patients from healthy pregnant women yielding an AUC as 0.826. Youden's index was maximal at the cutoff value of 8.5/4 mL with sensitivity and specificity at 53.66% and 100%, respectively. SALL4 expression was evaluated in GTD patients with CTC count greater than cutoff value. SALL4 high expressing CTCs (>2 signal dots) were detected in 66.67% (10/15) of malignant GTD patients but not in benign patients (0/5).

CONCLUSION

Differential expression of SALL4 was seen in CTCs derived from hydatidiform moles and GTN. CTC profiling may be developed as an adjunct marker to diagnose GTN.

Minimal residual disease in advanced or metastatic solid cancers: The G0-G1 state and immunotherapy are key to unwinding cancer complexity

In the last decade, a large amount of research has focused on elucidating the mechanisms that account for homing disseminated cancer cells (DCCs) from solid tumours to distant organs, which successively progress to overt metastatic disease; this is currently incurable. A better understanding of DCC behaviour is expected to allow detectable metastasis prevention by more effectively targeting 'metastatic seeds before they sprout'. As DCC biology co-evolved with that of the primary tumour, and due to the many similarities between them, the term 'niche' has been borrowed from normal adult stem cells (ASCs) to define the site of DCC metastatic colonisation. Moreover, heterogeneity, survival, protection, stemness and plasticity as well as the prolonged G0-G1 dormant state in the metastatic niche have been the main aspects of intense investigation. Consistent with these findings, in solid cancers with minimal residual disease (MRD), it has been proposed to prolong adjuvant therapy by targeting specific molecular pathway(s) involving DCC dormancy. However, so far, few disappointing clinical data have been reported. As an alternative strategy, because immune-surveillance contributes to the steady state of the DCC population and likely to the G0-G1 state of cancer cells, we have used prolonged immune-modulatory cytostatic chemotherapy, active immune stimulation with an INF-β/IL-2 sequence or drugs inhibiting myeloid-derived suppressor cell (MDSC)/Treg-mediated immune suppression. This strategy, mainly aimed at boosting the immune response, is based on recent findings suggesting the downregulation of immune escape mechanisms as well as other principal hallmarks during the G0-G1 state and/or in MRD. Preliminary clinical and/or laboratory data suggest the efficacy of this strategy in gastrointestinal and some endocrine-dependent cancers. Following this, we propose therapeutic schedules to prevent DCC activation and proliferation in solid cancers at a high risk of relapse or as maintenance therapy in metastatic patients after complete response (CR) to conventional treatment.

The combination of CTCs and CEA can help guide the management of patients with SPNs suspected of being lung cancer

Objective

Solitary pulmonary nodules (SPNs) is a common radiographic finding and require further evaluation because of the possibility of lung cancer. This study aimed to determine the sensitivity and specificity of circulating tumour cells (CTCs) as a marker for the diagnosis of SPNs and the integration of CTCs, carcinoembryonic antigen (CEA) and imaging findings to improve the sensitivity and specificity of diagnosis in patients with SPNs suspected of being lung cancer.

Method

For the serum biomarker assay, the concentration of CEA was measured by an automated electrochemiluminescence analyzer. CTCs were collected from 6 ml of blood by the SE i-FISH method, which detects the gene copy number in eight chromosomes and the tumour-associated antigen CK18.

Results

With a threshold of 6 CTC units, the method showed a sensitivity of 67.1% and a specificity of 56.5% in the diagnosis of NSCLC, especially in the upper lobe, in which the diagnostic strength was the highest (P < 0.01). CTCs, CEA and nodule type had the highest diagnostic efficacy (area under the curve, 0.827; 95% confidence interval, 0.752–0.901) in patients with SPNs being suspected lung cancer. Combining CTCs (cut-off value 12 units) with CEA (1.78 ng/ml), the method showed a sensitivity of 77.8% and a specificity of 90% in the diagnosis of NSCLC, especially in the upper lobe, subsolid nodules and nodules ≥8 mm.

Conclusions

Our results demonstrated that CTCs are feasible diagnostic biomarkers in patients with SPNs, especially in the upper lobe. Furthermore, CTCs combined with CEA showed higher diagnostic efficacy in the upper lobe, subsolid nodules and nodules ≥8 mm.

Current progress in the clinical use of circulating tumor cells as prognostic biomarkers

The process of metastasis is characterized by the shedding of tumor cells into the bloodstream, where they are transported to other parts of the body to seed new tumors. These cells, known as circulating tumor cells (CTCs), have the potential to reveal much about an individual cancer case, and theoretically can aid in the prediction of outcomes and design of precision treatments. Recent advances in technology now allow for the robust and reproducible characterization of CTCs from a simple blood draw. Both the number of circulating cells and important molecular characteristics correlated with clinical phenotypes such as drug resistance can be obtained and used for real-time prognostic analysis. Molecular characterization can provide a snapshot of the activity of the main tumor (serving as a "liquid biopsy") and early warnings concerning changes such as the development of resistance, and aid in predicting the efficacy of different therapeutic approaches for treatment optimization. Herein, the authors review the current clinical use of CTCs as prognostic biomarkers for several different cancers. The quantification of CTCs can lead to more accurate staging and decision making regarding options such as adjuvant chemotherapy.

Circulating Tumor Cells as a Tool for Assessing Tumor Heterogeneity

Tumor heterogeneity is the major cause of failure in cancer prognosis and prediction. Accurately detecting heterogeneity for the development of biomarkers and the detection of the clones resistant to therapy is one of the main goals of contemporary medicine. Metastases belong to the natural history of cancer. The present review gives an overview on the origin of tumor heterogeneity. Recent progress has made it possible to isolate and characterize circulating tumor cells (CTCs), which are the drivers of the disease between the primary sites and metastatic foci. The most recent methods for characterizing CTCs are summarized and we discuss the power of CTC profiling for analyzing tumor heterogeneity in early and advanced diseases.

Circulating Tumor Cell Detection in Lung Cancer: But to What End?

The understanding of the natural history and biology of lung cancer has been enhanced by studies into circulating tumor cells (CTCs). Fundamental and translational research, as well as clinical trials in the characterization and behavior of these cells, have constantly contributed to improving understanding within the domain of thoracic oncology. However, the use of these CTCs as prognostic and predictive biomarkers has not been adopted to the same extent as circulating free DNA (cf-DNA) in plasma, in the daily practice of thoracic oncologists. However, recent technological advances have firmly put the detection and characterization of CTCs in thoracic oncology back on the agenda, and have opened up perspectives for their routine clinical use. This review discusses the major advances of using CTCs in the domain of thoracic oncology, as well as the envisaged short- and long-term prospects.

Phenotypes of circulating tumour cells predict time to castration resistance in metastatic castration-sensitive prostate cancer

OBJECTIVES

To identify biomarkers that predict the response to standard androgen deprivation therapy (ADT) of patients newly diagnosed with metastatic castration-sensitive prostate cancer (CSPC) in order to improve therapeutic decision-making, and to investigate whether the characterization of baseline circulating tumour cells (CTCs) would predict the effective period of standard ADT.

MATERIALS AND METHODS

The study included 108 patients newly diagnosed with high-volume metastatic CSPC. Enumeration and characterization of patients' baseline CTCs (CTCs+ and CTCs-, indicating detectable and undetectable CTCs, respectively) were performed using the CanPatrol technique, which detects markers of the epithelial to mesenchymal transition (EMT) in CTCs, and classifies CTCs into epithelial, biophenotypic and mesenchymal phenotypes.

RESULTS

After a median follow-up of 24 months, 90 patients (83.3%) progressed to castration-resistant prostate cancer (CRPC), 93 patients (86.1%) had detectable CTCs, and the median number of CTCs was 4. The rate of progression to CRPC was significantly higher for patients with mesenchymal CTCs+ than for patients with CTCs+/mesenchymal CTCs- and CTCs- (93.1% vs 71.4% and 73.3%; P = 0.013). The median time to CRPC for patients with mesenchymal CTCs+ was significantly shorter than for those with CTCs+/mesenchymal CTCs- and CTCs- (10.5 months vs 18.0 and 14.0 months; P = 0.003). Multivariate Cox regression analysis suggested that the CTC phenotype was the only independent prognostic factor influencing the progression of disease from CSPC to CRPC.

CONCLUSIONS

Characterization of baseline CTCs according to the EMT phenotype predicted the effective period of standard ADT for patients newly diagnosed with metastatic CSPC. These findings are important for counselling patients and designing clinical trials.

Liquid biopsy of cancer: a multimodal diagnostic tool in clinical oncology

Over the last decades, the concept of precision medicine has dramatically renewed the field of medical oncology; the introduction of patient-tailored therapies has significantly improved all measurable outcomes. Liquid biopsy is a revolutionary technique that is opening previously unexpected perspectives. It consists of the detection and isolation of circulating tumor cells, circulating tumor DNA and exosomes, as a source of genomic and proteomic information in patients with cancer. Many technical hurdles have been resolved thanks to newly developed techniques and next-generation sequencing analyses, allowing a broad application of liquid biopsy in a wide range of settings. Initially correlated to prognosis, liquid biopsy data are now being studied for cancer diagnosis, hopefully including screenings, and most importantly for the prediction of response or resistance to given treatments. In particular, the identification of specific mutations in target genes can aid in therapeutic decisions, both in the appropriateness of treatment and in the advanced identification of secondary resistance, aiming to early diagnose disease progression. Still application is far from reality but ongoing research is leading the way to a new era in oncology. This review summarizes the main techniques and applications of liquid biopsy in cancer.

Metabolic reprogramming-based characterization of circulating tumor cells in prostate cancer

BACKGROUND

Circulating tumor cells (CTCs), an advantageous target of liquid biopsy, is an important biomarker for the prognosis and monitoring of cancer. Currently, detection techniques for CTCs are mainly based on the physical and/or epithelial characteristics of tumor cells. However, biofunctional activity markers that can indicate the high metastatic capacity of CTCs are lacking.

METHODS

Functional microarray, quantitative real-time polymerase chain reaction, and Western blot were used on five prostate cancer cell lines with different metastatic capacities to identify the metastasis-related metabolic genes. The identified genes were detected in the CTCs of 64 clinical samples using the RNA in situ hybridization. A multi-criteria weighted model was used to determine the optimal metabolic markers for the CTCs test. Based on five fluorescent signals targeting DAPI, CD45, metabolic, epithelial (EpCAM/CKs), and mesenchymal (Vimentin/Twist) markers, the filtration-enriched CTCs were classified as GM⁺CTCs/GM^-CTCs (metabolic types) or E-CTCs/H-CTCs/M-CTCs (EMT types). Correlation analysis and ROC curve were conducted on 54 prostate cancer samples to evaluate the clinical significance of CTCs subtypes.

RESULTS

Eight metastasis-related metabolic genes were identified, including HK2, PDP2, G6PD, PGK1, PHKA1, PYGL, PDK1, and PKM2. Among them, PGK1 and G6PD were determined as optimal glucose metabolic (GM) markers for CTCs. GM⁺CTCs (marked by PGK1/G6PD) were detectable in 64.8% (35/54) of prostate cancer patients, accounting for 46.5% (134/288) of total CTCs. An increased GM⁺CTCs level was associated with advanced tumor stage and metastasis (P <  0.05). In the discrimination of cancer metastasis from non-metastasis, GM⁺CTCs presented a higher AUC of the ROC curve (0.780) compared with the EMT CTCs subtypes (E-CTCs 0.729, H-CTCs 0.741, and M-CTCs 0.648). A triple tPSA-Gleason-GM⁺CTCs marker increased the AUC to 0.904, which was better than that of the tPSA-Gleason-H-CTCs marker (0.874).

CONCLUSIONS

The metabolic marker (PGK1/G6PD) is determined as the indicator for the biofunctional activity analysis of CTCs, compared with the existing morphological (EMT) classification on CTCs. The metabolic characterization of CTCs demonstrates that hypermetabolic GM⁺CTCs are promising biomarkers for prostate cancer metastasis.