Evaluation and consequences of heterogeneity in the circulating tumor cell compartment

Tumor-Intrinsic Galectin-3 Suppresses Melanoma Metastasis

Melanoma poses a poor prognosis with high mortality rates upon metastasis. Exploring the molecular mechanisms governing melanoma progression paves the way for developing novel approaches to control melanoma metastasis and ultimately enhance patient survival rates. Extracellular galectin-3 (Gal-3) has emerged as a pleiotropic promoter of melanoma metastasis, exerting varying activities depending on its interacting partner. However, whether intracellular Gal-3 promotes melanoma aggressive behavior remains unknown. In this study, we explored Gal-3 expression in human melanoma tissues as well as in murine melanoma models to examine its causal role in metastatic behavior. We found that Gal-3 expression is downregulated in metastatic melanoma tissues compared with its levels in primary melanomas. Enforced silencing of Gal-3 in melanoma cells promoted migration, invasion, colony formation, in vivo xenograft growth, and metastasis and activated canonical oncogenic signaling pathways. Moreover, loss of Gal-3 in melanoma cells resulted in upregulated the expression of the prometastatic transcription factor NFAT1 and its downstream metastasis-associated proteins, matrix metalloproteinase 3, and IL-8. Overall, our findings implicate melanoma intracellular Gal-3 as a major determinant of its metastatic behavior and reveal a negative regulatory role for Gal-3 on the expression of NFAT1 in melanoma cells.

Mechanical factors driving cancer progression

A fundamental step of tumor metastasis is tumor cell migration away from the primary tumor site. One mode of migration that is essential but still understudied is collective invasion, the process by which clusters of cells move in a coordinated fashion. In recent years, there has been growing interest to understand factors regulating collective invasion, with increasing number of studies investigating the biomechanical regulation of collective invasion. In this review we discuss the dynamic relationship between tumor microenvironment cues and cell response by first covering mechanical factors in the microenvironment and second, discussing the mechanosensing pathways utilized by cells in collective clusters to dynamically respond to mechanical matrix cues. Finally, we discuss model systems that have been developed which have increased our understanding of the mechanical factors contributing to tumor progression.

A Cdh3-β-catenin-laminin signaling axis in a subset of breast tumor leader cells control leader cell polarization and directional collective migration

Carcinoma dissemination can occur when heterogeneous tumor and tumor-stromal cell clusters migrate together via collective migration. Cells at the front lead and direct collective migration, yet how these leader cells form and direct migration are not fully appreciated. From live videos of primary mouse and human breast tumor organoids in a 3D microfluidic system mimicking native breast tumor microenvironment, we developed 3D computational models, which hypothesize that leader cells need to generate high protrusive forces and overcome extracellular matrix (ECM) resistance at the leading edge. From single-cell sequencing analyses, we find that leader cells are heterogeneous and identify and isolate a keratin 14- and cadherin-3-positive subpopulation sufficient to lead collective migration. Cdh3 controls leader cell protrusion dynamics through local production of laminin, which is required for integrin/focal adhesion function. Our findings highlight how a subset of leader cells interact with the microenvironment to direct collective migration.

Prognostic significance of circulating tumor cell measurement in the peripheral blood of patients with nasopharyngeal carcinoma

OBJECTIVE

Nasopharyngeal Carcinoma (NPC) is lethal cancer. Typically, relapse and metastasis are the outcomes of most patients. Against this backdrop, this study aimed to investigate the correlation between Circulating Tumor Cell (CTC) profiles and clinicopathological features in patients with NPC.

PATIENTS AND METHODS

A total of 119 blood samples from 79 patients were collected from patients with NPC during treatment. CanPatrol^TM CTC enrichment and RNA In Situ Hybridization (RNA-ISH) were used to characterize CTCs, including epithelial, Mesenchymal (MCTCs), and epithelial/mesenchymal mixed types according to their surface markers.

RESULTS

The number of CTCs and MCTCs in the pre-treatment group was significantly higher than that in the post-treatment group (p < 0.05). The total number of CTCs and MCTCs cell numbers was significant correlation with Tumor-Node-Metastasis (TNM) staging (p < 0.05), Progression-Free Survival (PFS), and Overall Survival (OS). The PFS of patients with > 7 CTCs or > 5 MCTCs per 5 mL blood was significantly shorter PFS than those patients with ≤ 7 CTCs or ≤ 5 MCTCs (p < 0.05). Patients treated with targeted therapy combined with chemoradiotherapy had poorer PFS and OS rates than those treated with chemoradiotherapy (p < 0.05). The Kaplan-Meier survival analysis also demonstrated that patients with changes in CTC > 4 were strongly associated with PFS and OS rates (p < 0.05).

CONCLUSION

CTC and MCTC number detection in patients with NPC is a useful biomarker for predicting patient progress. Patients with more than 7 CTCs or 5 MCTCs in 5 mL of blood had shorter PFS and OS rates. CTC and MCTC count changes were also significantly associated with the patient's therapy.

Whole Genome Sequencing of Single-Circulating Tumor Cell Ameliorates Unraveling Breast Cancer Heterogeneity

Objective

Because tumor tissues are most frequently heterogeneous and hard to characterize, the resulting therapeutic strategy could be misled. The most active and invasive tumor cells are circulating tumor cells (CTCs). In this study, we investigated the feasibility of individualized treatment of breast cancer patients based on whole genome sequencing (WGS) of single cell CTC.

Methods

Twenty-four CTCs were identified in three breast cancer patients. For each patient, one polyploid CTC was captured, and on which the WGS was performed. WGS was considered due to its sequencing robustness compared to conventional sequencing approaches. Based on the histopathological Her-2 status in tumor tissue and the HER2 gene status in WGS results of CTC, we adjusted treatment strategies and monitored disease progression.

Results

Patients ID1 and ID2 are found to be Her-2 positive in primary tumors and HER2 gene amplification in the DNA of CTCs. In-patient ID3, histopathological examination of the primary tumor and liver metastases revealed Her-2 negative, but the WGS analysis of CTC showed HER2 gene amplification. After adjusting treatment by adding Her-2 inhibitors according to the results of CTC sequencing, liver metastases and pleural effusion were significantly reduced two months later, CTC number and ctDNA burden were decreased, and 18-months progression-free survival (PFS) was recorded. In addition, some potential therapeutic targets and mutations in drug-resistant genes were detected.

Conclusion

The results of CTC sequencing effectively guided the treatment of a patient with HER2 gene amplification in CTC but with Her-2 negative on tumor tissue. Therefore, CTC sequencing could help resolve the heterogeneity of tumors and provide precision medicine for patients.

Integrated analysis revealing the role of TET3-mediated MUC13 promoter hypomethylation in hepatocellular carcinogenesis

Aim: To explore the function and underlying mechanism of MUC13 in hepatocellular carcinoma (HCC) oncogenesis. Materials & Methods: Online databases and software were used to perform analyses of expression, methylation and enrichment pathway. Experiments were performed to confirm the results using HCC cells in vitro. Results: MUC13 was upregulated in HCC and liver cancer stem cells (CSCs) and had a positive influence on CSC generation. Further analyses revealed that MUC13 with promoter hypomethylated was regulated by DNA demethylase TET3, which was overexpressed in HCC and liver CSCs. Conclusion: These results strongly suggested that high TET3 expression in liver CSCs may mediate MUC13 upregulation via promoter hypomethylation and thereby contribute to hepatocellular carcinogenesis.

Clinical Relevancy of Circulating Tumor Cells in Breast Cancer: Epithelial or Mesenchymal Characteristics, Single Cells or Clusters?

Metastatic breast cancer (MBC) is typically an incurable disease with high mortality rates; thus, early identification of metastatic features and disease recurrence through precise biomarkers is crucial. Circulating tumor cells (CTCs) consisting of heterogeneous subpopulations with different morphology and genetic, epigenetic, and gene expression profiles represent promising candidate biomarkers for metastatic potential. The experimentally verified role of epithelial-to-mesenchymal transition in cancer dissemination has not been clearly described in BC patients, but the stemness features of CTCs strongly contributes to metastatic potency. Single CTCs have been shown to be protected in the bloodstream against recognition by the immune system through impaired interactions with T lymphocytes and NK cells, while associations of heterotypic CTC clusters with platelets, leucocytes, neutrophils, tumor-associated macrophages, and fibroblasts improve their tumorigenic behavior. In addition to single CTC and CTC cluster characteristics, we reviewed CTC evaluation methods and clinical studies in early and metastatic BCs. The variable CTC tests were developed based on specific principles and strategies. However, CTC count and the presence of CTC clusters were shown to be most clinically relevant in existing clinical trials. Despite the known progress in CTC research and sampling of BC patients, implementation of CTCs and CTC clusters in routine diagnostic and treatment strategies still requires improvement in detection sensitivity and precise molecular characterizations, focused predominantly on the role of CTC clusters for their higher metastatic potency.

Clinical significance of circulating tumor cells in predicating the outcomes of patients with colorectal cancer

BACKGROUND

Relapse and metastasis of patients with Colorectal Cancer (CRC) is the major obstacle to the long-term life of patients. Its mechanisms remain defined.

METHODS

A total of 48 CRC patients were enrolled and 68 samples were obtained from the peripheral blood of patients before or after treatments in this study. Twenty non-cancer patients were also detected as a negative control. Circulating Tumor Cells (CTCs), including Epithelial CTCs (eCTCs), Mesenchymal (MCTCs), and epithelial/mesenchymal mixed phenotypes (mixed CTCs), were identified by CanPatrol^TM CTC enrichment and RNA in situ hybridization. The relationship between CTCs number and Progression-Free Survival (PFS) or Overall Survival (OS) was evaluated.

RESULTS

Thirty-four of 48 patients (70.8%) were found to have positive CTCs. Total CTCs and MCTCs in the post-treatment had a significant correlation PFS and OS. When total CTCs or MCTCs in 5 mL blood of patients were more than 6 CTCs or 5 MCTCs, PFS of the patients was significantly shorter (p < 0.05) than that in patients with less than 6 CTCs or 5 MCTCs. The patients with > 5 CTCs count changes were found to exhibit poor PFS and OS rates (p < 0.05).

CONCLUSION

Total CTCs and MCTCs number detection in patients with colorectal cancer was very useful biomarker for predicting the prognosis of patients. Higher CTCs or MCTCs had poorer PFS and OS rates.

Role of Circulating Biomarkers in Platinum-Resistant Ovarian Cancer

Ovarian cancer (OC) is the second most common cause of death in women with gynecological cancer. Considering the poor prognosis, particularly in the case of platinum-resistant (PtR) disease, a huge effort was made to define new biomarkers able to help physicians in approaching and treating these challenging patients. Currently, most data can be obtained from tumor biopsy samples, but this is not always available and implies a surgical procedure. On the other hand, circulating biomarkers are detected with non-invasive methods, although this might require expensive techniques. Given the fervent hope in their value, here we focused on the most studied circulating biomarkers that could play a role in PtR OC.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 7: PD-L1 Expression in Liquid Biopsy

Liquid biopsy is an accessible, non-invasive diagnostic tool for advanced prostate cancer (PC) patients, potentially representing a real-time monitoring test for tumor evolution and response to treatment through the analysis of circulating tumor cells (CTCs) and exosomes. We performed a systematic literature review (PRISMA guidelines) to describe the current knowledge about PD-L1 expression in liquid biopsies of PC patients: 101/159 (64%) cases revealed a variable number of PD-L1+ CTCs. Outcome correlations should be investigated in larger series. Nuclear PD-L1 expression by CTCs was occasionally associated with worse prognosis. Treatment (abiraterone, enzalutamide, radiotherapy, checkpoint-inhibitors) influenced PD-L1+ CTC levels. Discordance in PD-L1 status was detected between primary vs. metastatic PC tissue biopsies and CTCs vs. corresponding tumor tissues. PD-L1 is also released by PC cells through soluble exosomes, which could inhibit the T cell function, causing immune evasion. PD-L1+ PC-CTC monitoring and genomic profiling may better characterize the ongoing aggressive PC forms compared to PD-L1 evaluation on primary tumor biopsies/prostatectomy specimens (sometimes sampled a long time before recurrence/progression). Myeloid-derived suppressor cells and dendritic cells (DCs), which may have immune-suppressive effects in tumor microenvironment, have been found in PC patients circulation, sometimes expressing PD-L1. Occasionally, their levels correlated to clinical outcome. Enzalutamide-progressing castration-resistant PC patients revealed increased PD-1+ T cells and circulating PD-L1/2+ DCs.

Prognostic and Therapeutic Significance of Circulating Tumor Cell Phenotype Detection Based on Epithelial-Mesenchymal Transition Markers in Early and Midstage Colorectal Cancer First-Line Chemotherapy

Purpose

Epithelial-mesenchymal transition (EMT) is related to the process of metastasis and challenges the detection of circulating tumor cells (CTCs) based on epithelial cell adhesion molecules. Circulating tumor cells (CTCs) have been proven to be a prognostic indicator of colorectal cancer (CRC). Although there is evidence that CTC heterogeneity based on EMT markers is associated with disease progression, no standard recommendations have been established for clinical practice. This study is aimed at evaluating the prognostic significance of dynamic CTC detection based on EMT for early and midstage colorectal cancer patients.

Methods

101 patients with early to midterm CRC were admitted from January 2016 to September 2018. All patients underwent CRC radical surgery and standard chemotherapy. Patients in the postchemotherapy were able to epithelial mesenchymal transformed (EMT) CTC testing in peripheral blood using the CanPatrol™ system. Multiple CTC tests were performed according to patient's own condition and different follow-up time points. Based on patient's basic information and follow-up data, the Kaplan-Meier method was utilized to establish the progression-free survival model, and the log-rank test was utilized to compare the survival rates between the two groups.

Result

Total CTC change of the patient is the best method to predict whether progression-free survival progresses in tumor patients (Area = 0.857). The second detection of total number of CTCs (P < 0.01) detected after chemotherapy, epithelial CTCs (P = 0.032), the increased total number of CTCs (P < 0.01), and the increased number of mesenchymal CTCs (P = 0.015) are significantly related with patient's poor progression-free survival.

Conclusion

Analysis of the second CTC count and classification after follow-up are more related to the survival prognosis of the tumor. The joint analysis of CTC dynamic monitoring data is a good tool to judge patient's survival prognosis.

Genome profiles of pathologist-defined cell clusters by multiregional LCM and G&T-seq in one triple-negative breast cancer patient

Pathological examination is the gold standard for cancer diagnosis, and breast tumor cells are often found in clusters. We report a case study on one triple-negative breast cancer (TNBC) patient, analyzing tumor development, metastasis, and prognosis with simultaneous DNA and RNA sequencing of pathologist-defined cell clusters from multiregional frozen sections. The cell clusters are isolated by laser capture microdissection (LCM) from primary tumor tissue, lymphatic vessels, and axillary lymph nodes. Data are reported for a total of 97 cell clusters. A combination of tumor cell-cluster clonality and phylogeny reveals 3 evolutionarily distinct pathways for this patient, each associated with a unique mRNA signature, and each correlated with disparate survival outcomes. Hub gene analysis indicates that extensive downregulation of ribosomal protein mRNA is a potential marker of poor prognosis in breast cancer.

Pathologically diverse cell clusters share genomic and transcriptomic profiles

Transcriptome-defined clones are more complex than genome-defined clones

Three distinct pathways were inferred, each with disparate survival outcomes

Lower expression of ribosomal proteins may be an indicator of poor prognosis

Comparison of Radiomic Features in a Diverse Cohort of Patients With Pancreatic Ductal Adenocarcinomas

Background

Significant racial disparities in pancreatic cancer incidence and mortality rates exist, with the highest rates in African Americans compared to Non-Hispanic Whites and Hispanic/Latinx populations. Computer-derived quantitative imaging or “radiomic” features may serve as non-invasive surrogates for underlying biological factors and heterogeneity that characterize pancreatic tumors from African Americans, yet studies are lacking in this area. The objective of this pilot study was to determine if the radiomic tumor profile extracted from pretreatment computed tomography (CT) images differs between African Americans, Non-Hispanic Whites, and Hispanic/Latinx with pancreatic cancer.

Methods

We evaluated a retrospective cohort of 71 pancreatic cancer cases (23 African American, 33 Non-Hispanic White, and 15 Hispanic/Latinx) who underwent pretreatment CT imaging at Moffitt Cancer Center and Research Institute. Whole lesion semi-automated segmentation was performed on each slice of the lesion on all pretreatment venous phase CT exams using Healthmyne Software (Healthmyne, Madison, WI, USA) to generate a volume of interest. To reduce feature dimensionality, 135 highly relevant non-texture and texture features were extracted from each segmented lesion and analyzed for each volume of interest.

Results

Thirty features were identified and significantly associated with race/ethnicity based on Kruskal-Wallis test. Ten of the radiomic features were highly associated with race/ethnicity independent of tumor grade, including sphericity, volumetric mean Hounsfield units (HU), minimum HU, coefficient of variation HU, four gray level texture features, and two wavelet texture features. A radiomic signature summarized by the first principal component partially differentiated African American from non-African American tumors (area underneath the curve = 0.80). Poorer survival among African Americans compared to Non-African Americans was observed for tumors with lower volumetric mean CT [HR: 3.90 (95% CI:1.19–12.78), p=0.024], lower GLCM Avg Column Mean [HR:4.75 (95% CI: 1.44,15.37), p=0.010], and higher GLCM Cluster Tendency [HR:3.36 (95% CI: 1.06–10.68), p=0.040], and associations persisted in volumetric mean CT and GLCM Avg Column after adjustment for key clinicopathologic factors.

Conclusions

This pilot study identified several textural radiomics features associated with poor overall survival among African Americans with PDAC, independent of other prognostic factors such as grade. Our findings suggest that CT radiomic features may serve as surrogates for underlying biological factors and add value in predicting clinical outcomes when integrated with other parameters in ongoing and future studies of cancer health disparities.

Precision Oncology Beyond Genomics: The Future Is Here-It Is Just Not Evenly Distributed

Cancer is a multifactorial disease with increasing incidence. There are more than 100 different cancer types, defined by location, cell of origin, and genomic alterations that influence oncogenesis and therapeutic response. This heterogeneity between tumors of different patients and also the heterogeneity within the same patient's tumor pose an enormous challenge to cancer treatment. In this review, we explore tumor heterogeneity on the longitudinal and the latitudinal axis, reviewing current and future approaches to study this heterogeneity and their potential to support oncologists in tailoring a patient's treatment regimen. We highlight how the ideal of precision oncology is reaching far beyond the knowledge of genetic variants to inform clinical practice and discuss the technologies and strategies already available to improve our understanding and management of heterogeneity in cancer treatment. We will focus on integrating multi-omics technologies with suitable in vitro models and their proficiency in mimicking endogenous tumor heterogeneity.

Microfluidic Chip-Based Cancer Diagnosis and Prediction of Relapse by Detecting Circulating Tumor Cells and Circulating Cancer Stem Cells

Detecting circulating tumor cells (CTCs) has been considered one of the best biomarkers in liquid biopsy for early diagnosis and prognosis monitoring in cancer. A major challenge of using CTCs is detecting extremely low-concentrated targets in the presence of high noise factors such as serum and hematopoietic cells. This review provides a selective overview of the recent progress in the design of microfluidic devices with optical sensing tools and their application in the detection and analysis of CTCs and their small malignant subset, circulating cancer stem cells (CCSCs). Moreover, discussion of novel strategies to analyze the differentiation of circulating cancer stem cells will contribute to an understanding of metastatic cancer, which can help clinicians to make a better assessment. We believe that the topic discussed in this review can provide brief guideline for the development of microfluidic-based optical biosensors in cancer prognosis monitoring and clinical applications.

Circulating Tumor Cells and Fibronectin 1 in the Prognosis of Nasopharyngeal Carcinoma

Objective:

Nasopharyngeal carcinoma is highly endemic in Southeast China. Circulating tumor cell is an important biomarker in the prognosis of variety kinds of cancers. Overexpression of fibronectin 1 was observed in variety kinds of malignancies and may contribute to progress and metastasis of the cancers. The current study was aimed to investigate phenotypes of circulating tumor cell in nasopharyngeal carcinoma blood and fibronectin 1 expression in the circulating tumor cell, and their clinical application in predicting nasopharyngeal carcinoma prognosis.

Methods:

Blood samples were obtained from nasopharyngeal carcinoma patients before and after treatment. CanPatrol circulating tumor cell enrichment and RNA in situ hybridization were applied to identify circulating tumor cell and its phenotypes. Fibronectin 1 messenger RNA expression in the cells of circulating tumors was examined by messenger RNA-in situ hybridization.

Results:

Circulating tumor cell was not associated with tumor characteristics or lymph node metastasis. Patients with >9 circulating tumor cells or >5 mesenchymal phenotype circulating tumor cell per 5-mL blood had poorer progression-free survival (P < .05). Multivariable analysis demonstrated that 2 or more mesenchymal phenotype circulating tumor cells with high fibronectin 1 messenger RNA expression predicted shorter progression-free survival (P < .05).

Conclusions:

Circulating tumor cells with high-level fibronectin 1 expression was associated with poor survival in patients with nasopharyngeal carcinoma and could be an independent prognostic factor for nasopharyngeal carcinoma.

Circulating tumor cell enumeration for improved screening and disease detection of patients with colorectal cancer

Background

The immunochemical fecal occult blood test (iFOBT) for colorectal cancer (CRC) screening and the serum carcinoembryonic antigen (CEA) assay for disease detection of CRC is associated with a high false-positive rate and a low detection sensitivity, respectively. There is an unmet need to define additional modalities to complement these assays. Different subsets of circulating tumor cells (CTCs) are present in the peripheral blood of cancer patients. Whether or not CTCs testing supplements these clinical assays and is valuable for patients with CRC was investigated.

Methods

CTCs were enriched from pre-operative patients with CRC (n = 109) and the non-cancerous controls (n = 65). CTCs expressing either epithelial cell adhesion molecule (EpCAM) or podoplanin (PDPN, the marker associated with poor cancer prognosis) were defined by immunofluorescence staining and were analyzed alone or in combination with iFOBT or serum CEA.

Results

Patients with early or advanced stage of CRC can be clearly identified and differentiated from the non-cancerous controls (p < 0.001) by EpCAM⁺-CTC or PDPN⁺-CTC count. The sensitivity and specificity of EpCAM⁺-CTCs was 85.3% and 78.5%, respectively, when the cutoff value was 23 EpCAM⁺-CTCs/mL of blood; and the sensitivity and specificity of PDPN⁺-CTCs was 78.0% and 75.4%, respectively, when the cutoff value was 7 PDPN⁺-CTCs/mL of blood. Combined analysis of iFOBT with the EpCAM⁺-CTC and PDPN⁺-CTC count reduced the false-positive rate of iFOBT from 56.3% to 18.8% and 23.4%, respectively. Combined analysis of serum CEA with the EpCAM⁺-CTC and PDPN⁺-CTC count increased the disease detection rate from 30.3% to 89.9% and 86.2%, respectively.

Conclusion

CTC testing could supplement iFOBT to improve CRC screening and supplement serum CEA assay for better disease detection of patients with CRC.

Multiphase computed tomography radiomics of pancreatic intraductal papillary mucinous neoplasms to predict malignancy

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are non-invasive pancreatic precursor lesions that can potentially develop into invasive pancreatic ductal adenocarcinoma. Currently, the International Consensus Guidelines (ICG) for IPMNs provides the basis for evaluating suspected IPMNs on computed tomography (CT) imaging. Despite using the ICG, it remains challenging to accurately predict whether IPMNs harbor high grade or invasive disease which would warrant surgical resection. A supplementary quantitative radiological tool, radiomics, may improve diagnostic accuracy of radiological evaluation of IPMNs. We hypothesized that using CT whole lesion radiomics features in conjunction with the ICG could improve the diagnostic accuracy of predicting IPMN histology.

AIM

To evaluate whole lesion CT radiomic analysis of IPMNs for predicting malignant histology compared to International Consensus Guidelines.

METHODS

Fifty-one subjects who had pancreatic surgical resection at our institution with histology demonstrating IPMN and available preoperative CT imaging were included in this retrospective cohort. Whole lesion semi-automated segmentation was performed on each preoperative CT using Healthmyne software (Healthmyne, Madison, WI). Thirty-nine relevant radiomic features were extracted from each lesion on each available contrast phase. Univariate analysis of the 39 radiomics features was performed for each contrast phase and values were compared between malignant and benign IPMN groups using logistic regression. Conventional quantitative and qualitative CT measurements were also compared between groups, via χ² (categorical) and Mann Whitney U (continuous) variables.

RESULTS

Twenty-nine subjects (15 males, age 71 ± 9 years) with high grade or invasive tumor histology comprised the "malignant" cohort, while 22 subjects (11 males, age 70 ± 7 years) with low grade tumor histology were included in the "benign" cohort. Radiomic analysis showed 18/39 precontrast, 19/39 arterial phase, and 21/39 venous phase features differentiated malignant from benign IPMNs (P < 0.05). Multivariate analysis including only ICG criteria yielded two significant variables: thickened and enhancing cyst wall and enhancing mural nodule < 5 mm with an AUC (95%CI) of 0.817 (0.709-0.926). Multivariable post contrast radiomics achieved an AUC (95%CI) of 0.87 (0.767-0.974) for a model including arterial phase radiomics features and 0.834 (0.716-0.953) for a model including venous phase radiomics features. Combined multivariable model including conventional variables and arterial phase radiomics features achieved an AUC (95%CI) of 0.93 (0.85-1.0) with a 5-fold cross validation AUC of 0.90.

CONCLUSION

Multi-phase CT radiomics evaluation could play a role in improving predictive capability in diagnosing malignancy in IPMNs. Future larger studies may help determine the clinical significance of our findings.

Genome‑wide copy number analysis of circulating tumor cells in breast cancer patients with liver metastasis

The genome‑wide copy number analysis of circulating tumor cells (CTCs) provides a promising prognostic biomarker for survival in breast cancer liver metastasis (BCLM) patients. The present study aimed to confirm the prognostic value of the presence of CTCs in BCLM patients. We previously developed an assay for the genome‑wide pattern differences in copy number variations (CNVs) as an adjunct test for the routine imaging and histopathologic diagnosis methods to distinguish newly diagnosed liver metastases and recurrent liver metastases. Forty‑three breast cancer patients were selected for this study in which 23 newly diagnosed and 20 recurrent liver metastases were diagnosed by histopathology and 18F‑FDG PET/CT imaging. CTCs were counted from all patients using the CellSearch system and were confirmed by cytomorphology and three‑color immunocytochemistry. Genomic DNA of single CTCs was amplified using multiple annealing and looping based amplification cycles (MALBAC). Then, we compared the CTC numbers of newly diagnosed and recurrent BCLM patients using Illumina platforms. A high CTC frequency (>15 CTCs/7.5 ml blood) was found to be correlated with disease severity and metastatic progression, which suggests the value for CTCs in the diagnosis of BCLM in comparison with pathohistology and PET/CT imaging (P>0.05). Moreover, CTCs isolated from BCLM patients remained an independent prognostic detection factor associated with overall survival (P=0.0041). Comparison between newly diagnosed and recurrent liver metastases revealed different frequencies of CNVs (P>0.05). Notably, the CNV pattern of isolated CTCs of recurrent BCLM patients was similar to recurrent liver metastases (nearly 82% of the gain/loss regions). Functional enrichment analysis identified 25 genes as a CNV signature of BCLM. Among them, were defensin and β‑defensin genes, which are significantly associated with anti‑angiogenesis and immunomodulation signaling pathways. High CTC frequencies are effective in the evaluation and differentiation between newly diagnosed liver metastases from recurrent liver metastases. Future clinical studies will be necessary to fully determine the prognostic potential of CTC cluster signatures in patients with BCLM.

Clinical significance of epithelial-mesenchymal transition typing of circulating tumour cells in colorectal cancer

AIM

The aim was to determine the diagnostic value of epithelial-mesenchymal transition typing of circulating tumour cells (CTCs) in colorectal cancer (CRC).

METHOD

Peripheral blood samples were collected from 51 CRC patients before anti-tumour treatment from April 2016 to June 2018 at the Peking University Shenzhen Hospital. The blood samples were analysed using the CanPatrol CTC typing technique (SurExam, Guangzhou, China), which combines nanomembrane enrichment with mRNA in situ hybridization. Based on the marker expression, the CTCs were classified into epithelial, epithelial mesenchymal and mesenchymal (M-CTC) types. The correlation between the CTC counts and clinicopathological characteristics such as gender, age, TNM stage, lymph node metastasis and distant metastasis were analysed by univariate and multivariate Cox regression models. The overall survival and progression-free survival (PFS) of patients demarcated by CTC typing were analysed using the Kaplan-Meier method and log-rank tests.

RESULT

M-CTCs were detected more frequently in patients with lymph node metastasis (N2 81.8%; N1 72.7%; N0 38.9%) as well as distant metastasis (M0 50%; M1a 81.25%; M1b 85.7%) compared to those without metastasis. In addition, the presence of M-CTCs was significantly correlated with distant metastasis (P < 0.01). Univariate analysis showed that lymph node metastasis (P = 0.035), distant metastasis (P < 0.001) and total CTC count ≥ 4 (P = 0.007) and M-CTC count ≥ 1 (P < 0.001) were significantly associated with unfavourable PFS, and lymph node metastasis (P = 0.04), distant metastasis (P = 0.01) and M-CTC count ≥ 1 (P < 0.001) were significantly associated with unfavourable overall survival. Multivariate analysis showed that the presence of M-CTCs was the only independent prognostic factor for poor PFS, and patients with M-CTCs had significantly shorter PFS than those without (P = 0.011).

CONCLUSION

M-CTCs are significantly associated with CRC severity and metastasis, and M-CTC count is an independent predictor of prognosis.

Circulating Tumor Cells Enumerated by a Centrifugal Microfluidic Device as a Predictive Marker for Monitoring Ovarian Cancer Treatment: A Pilot Study

We investigated the size-based isolation and enumeration of circulating tumor cells (CTCs) using a centrifugal microfluidic device equipped with a fluid-assisted separation technology (FAST) disc. We further assessed the correlations among CTCs, cancer antigen-125 (CA125) levels, and clinical course of the disease in a prospective analysis of 47 serial blood samples collected at multiple time-points from 13 ovarian cancer patients. CTCs were isolated from whole blood using the FAST disc and were classified as epithelial cell adhesion molecule (EpCAM)/cytokeratin+, CD45-, and 4',6-diamidino-2-phenylindole (DAPI)+. Mean CTC count at baseline was 20.2; 84.62% of patients had more than one CTC at baseline and had decreased CTCs counts after surgery and chemotherapy. The CTC counts in eight patients with complete responses were <3. CTC counts were correlated with CA125 levels in three patients without recurrence; they were elevated in three patients with recurrence and normal CA125 concentrations. CTC counts and CA125 levels showed high concordance with directional changes (increasing 71.4%; non-increasing 75.0%). CTC counts showed higher associations with clinical status, sensitivity (100.0% vs. 60.0%), positive predictive value (55.6% vs. 42.9%), and negative predictive value (100.0% vs. 87.5%) than CA125 levels. CTC counts were better associated with treatment response and recurrence than CA125 levels.

Tracking cancer progression: from circulating tumor cells to metastasis

The analysis of circulating tumor cells (CTCs) is an outstanding tool to provide insights into the biology of metastatic cancers, to monitor disease progression and with potential for use in liquid biopsy-based personalized cancer treatment. These goals are ambitious, yet recent studies are already allowing a sharper understanding of the strengths, challenges, and opportunities provided by liquid biopsy approaches. For instance, through single-cell-resolution genomics and transcriptomics, it is becoming increasingly clear that CTCs are heterogeneous at multiple levels and that only a fraction of them is capable of initiating metastasis. It also appears that CTCs adopt multiple ways to enhance their metastatic potential, including homotypic clustering and heterotypic interactions with immune and stromal cells. On the clinical side, both CTC enumeration and molecular analysis may provide new means to monitor cancer progression and to take individualized treatment decisions, but their use for early cancer detection appears to be challenging compared to that of other tumor derivatives such as circulating tumor DNA. In this review, we summarize current data on CTC biology and CTC-based clinical applications that are likely to impact our understanding of the metastatic process and to influence the clinical management of patients with metastatic cancer, including new prospects that may favor the implementation of precision medicine.

Measure Twice: Promise of Liquid Biopsy in Pediatric High-Grade Gliomas

Purpose

To review and critique the current state of liquid biopsy in pHGG.

Materials and Methods

Published literature was reviewed for articles related to liquid biopsy in pediatric glioma and adult glioma with a focus on high-grade gliomas.

Results

This review discusses the current state of liquid biomarkers of pHGG and their potential applications for liquid biopsy development.

Conclusions

While nascent, the progress toward identifying circulating analytes of pHGG primes the field of neuro-oncoogy for liquid biopsy development.

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

Purpose

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

Patients and methods

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

Results

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

Conclusion

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

Serum proteomic analysis of melanoma patients with immunohistochemical profiling of primary melanomas and cultured cells: Pilot study

The steadily increasing incidence of malignant melanoma (MM) and its aggressive behaviour makes this tumour an attractive cancer research topic. The tumour microenvironment is being increasingly recognised as a key factor in cancer biology, with an impact on proliferation, invasion, angiogenesis and metastatic spread, as well as acquired therapy resistance. Multiple bioactive molecules playing cooperative roles promote the chronic inflammatory milieu in tumours, making inflammation a hallmark of cancer. This specific inflammatory setting is evident in the affected tissue. However, certain mediators can leak into the systemic circulation and affect the whole organism. The present study analysed the complex inflammatory response in the sera of patients with MM of various stages. Multiplexed proteomic analysis (Luminex Corporation) of 31 serum proteins was employed. These targets were observed in immunohistochemical profiles of primary tumours from the same patients. Furthermore, these proteins were analysed in MM cell lines and the principal cell population of the melanoma microenvironment, cancer‑associated fibroblasts. Growth factors such as hepatocyte growth factor, granulocyte‑colony stimulating factor and vascular endothelial growth factor, chemokines RANTES and interleukin (IL)‑8, and cytokines IL‑6, interferon‑α and IL‑1 receptor antagonist significantly differed in these patients compared with the healthy controls. Taken together, the results presented here depict the inflammatory landscape that is altered in melanoma patients, and highlight potentially relevant targets for therapy improvement.

Circulating Tumour Cell Biomarkers in Head and Neck Cancer: Current Progress and Future Prospects

Head and neck cancer (HNC) continues to carry a significant burden of disease both for patients and health services. Facilitating biomarker-led treatment decisions is critical to improve outcomes in this group and deliver therapy tailored to the individual tumour biological profile. One solution to develop such biomarkers is a liquid biopsy analysing circulating tumour cells (CTCs)-providing a non-invasive and dynamic assessment of tumour specific alterations in 'real-time'. A major obstacle to implementing such a test is the standardisation of CTC isolation methods and subsequent down-stream analysis. Several options are available, with a recent shift in vogue from positive-selection marker-dependent isolation systems to marker-independent negative-selection techniques. HNC single-CTC characterisation, including single-cell sequencing, to identify actionable mutations and gene-expression signatures has the potential to both guide the understanding of patient tumour heterogeneity and support the adoption of personalised medicine strategies. Microfluidic approaches for isolating CTCs and cell clusters are emerging as novel technologies which can be incorporated with computational platforms to complement current diagnostic and prognostic strategies. We review the current literature to assess progress regarding CTC biomarkers in HNC and potential avenues for future translational research and clinical implementation.

Liquid Biopsies for Ovarian Carcinoma: How Blood Tests May Improve the Clinical Management of a Deadly Disease

Ovarian cancers (OvC) are frequent, with more than 22,000 new cases each year for 14,000 deaths in the United States. Except for patients with BRCA1 or BRCA2 mutations, diagnostic methods, prognostic tools, and therapeutic strategies have not much improved in the last two decades. High throughput tumor molecular analyses have identified important alterations involved in ovarian carcinoma growth and spreading. However, these data have not modified the clinical management of most of patients. Moreover, tumor sample collection requires invasive procedures not adapted to objectives, such as the screening, prediction, or assessment of treatment efficacy, monitoring of residual disease, and early diagnosis of relapse. In recent years, circulating tumor biomarkers (also known as "liquid biopsies") such as circulating tumor cells, circulating nucleotides (DNA or miRNA), or extracellular vesicles, have been massively explored through various indications, platforms, and goals, but their use has not yet been validated in routine practice. This review describes the methods of analysis and results related to liquid biopsies for ovarian epithelial cancer. The different settings that a patient can go through during her journey with OvC are explored: screening and early diagnosis, prognosis, prediction of response to systemic therapies for advanced stages, and monitoring of residual subclinical disease.

Liquid Biopsies for Ovarian Carcinoma: How Blood Tests May Improve the Clinical Management of a Deadly Disease

Ovarian cancers (OvC) are frequent, with more than 22,000 new cases each year for 14,000 deaths in the United States. Except for patients with BRCA1 or BRCA2 mutations, diagnostic methods, prognostic tools, and therapeutic strategies have not much improved in the last two decades. High throughput tumor molecular analyses have identified important alterations involved in ovarian carcinoma growth and spreading. However, these data have not modified the clinical management of most of patients. Moreover, tumor sample collection requires invasive procedures not adapted to objectives, such as the screening, prediction, or assessment of treatment efficacy, monitoring of residual disease, and early diagnosis of relapse. In recent years, circulating tumor biomarkers (also known as "liquid biopsies") such as circulating tumor cells, circulating nucleotides (DNA or miRNA), or extracellular vesicles, have been massively explored through various indications, platforms, and goals, but their use has not yet been validated in routine practice. This review describes the methods of analysis and results related to liquid biopsies for ovarian epithelial cancer. The different settings that a patient can go through during her journey with OvC are explored: screening and early diagnosis, prognosis, prediction of response to systemic therapies for advanced stages, and monitoring of residual subclinical disease.

Liquid Biopsies for Ovarian Carcinoma: How Blood Tests May Improve the Clinical Management of a Deadly Disease

Ovarian cancers (OvC) are frequent, with more than 22,000 new cases each year for 14,000 deaths in the United States. Except for patients with BRCA1 or BRCA2 mutations, diagnostic methods, prognostic tools, and therapeutic strategies have not much improved in the last two decades. High throughput tumor molecular analyses have identified important alterations involved in ovarian carcinoma growth and spreading. However, these data have not modified the clinical management of most of patients. Moreover, tumor sample collection requires invasive procedures not adapted to objectives, such as the screening, prediction, or assessment of treatment efficacy, monitoring of residual disease, and early diagnosis of relapse. In recent years, circulating tumor biomarkers (also known as "liquid biopsies") such as circulating tumor cells, circulating nucleotides (DNA or miRNA), or extracellular vesicles, have been massively explored through various indications, platforms, and goals, but their use has not yet been validated in routine practice. This review describes the methods of analysis and results related to liquid biopsies for ovarian epithelial cancer. The different settings that a patient can go through during her journey with OvC are explored: screening and early diagnosis, prognosis, prediction of response to systemic therapies for advanced stages, and monitoring of residual subclinical disease.

Spectrum of Epithelial-Mesenchymal Transition Phenotypes in Circulating Tumour Cells from Early Breast Cancer Patients

Circulating tumour cells (CTCs) can provide valuable prognostic information in a number of epithelial cancers. However, their detection is hampered due to their molecular heterogeneity, which can be induced by the epithelial-mesenchymal transition (EMT) process. Therefore, current knowledge about CTCs from clinical samples is often limited due to an inability to isolate wide spectrum of CTCs phenotypes. In the current work, we aimed at isolation and molecular characterization of CTCs with different EMT status in order to establish their clinical significance in early breast cancer patients. We have obtained CTCs-enriched blood fraction from 83 breast cancer patients in which we have tested the expression of epithelial, mesenchymal and general breast cancer CTCs markers (MGB1/HER2/CK19/CDH1/CDH2/VIM/PLS3), cancer stem cell markers (CD44, NANOG, ALDH1, OCT-4, CD133) and cluster formation gene (plakoglobin). We have shown that in the CTCs-positive patients, epithelial, epithelial-mesenchymal and mesenchymal CTCs markers were detected at a similar rate (in 28%, 24% and 24%, respectively). Mesenchymal CTCs were characterized by the most aggressive phenotype (significantly higher expression of CXCR4, uPAR, CD44, NANOG, p < 0.05 for all), presence of lymph node metastases (p = 0.043), larger tumour size (p = 0.023) and 7.33 higher risk of death in the multivariate analysis (95% CI 1.06–50.41, p = 0.04). Epithelial-mesenchymal subtype, believed to correspond to highly plastic and aggressive state, did not show significant impact on survival. Gene expression profile of samples with epithelial-mesenchymal CTCs group resembled pure epithelial or pure mesenchymal phenotypes, possibly underlining degree of EMT activation in particular patient’s sample. Molecular profiling of CTCs EMT phenotype provides more detailed and clinically informative results, proving the role of EMT in malignant cancer progression in early breast cancer.

CD44+ cytokeratin-positive tumor cells in blood and bone marrow are associated with poor prognosis of patients with gastric cancer

BACKGROUND

The phenotypic heterogeneity of circulating tumor cells (CTC) in peripheral blood and disseminated tumor cells (DTC) in bone marrow is an important constraint for clinical decision making. Here, we investigated the implications of two different subpopulations of these cells in gastric cancer (GC).

METHODS

GC patients (n = 228) who underwent elective gastric resections were prospectively examined for CTC/DTC. The cells obtained from peripheral blood and bone marrow aspirates were sorted by flow cytometry and CD45^- cells expressing cytokeratins (8, 18, and 19) and CD44 were identified by immunofluorescent double staining.

RESULTS

Ninety-three (41%) patients had cytokeratin-positive tumor cells in either blood or bone marrow, while cells expressing CD44 were found in 22 (10%) cases. CK⁺CD44⁺ cells were significantly more common among patients with distant metastases (50 vs 19%, P = 0.001), while no such correlations were demonstrated for CK⁺CD44^- cells. Detection of CK⁺CD44⁺ cells, but not CK⁺CD44^-, was associated with significantly shortened survival. Moreover, the Cox proportional hazards model identified CK⁺CD44⁺ cells as a negative prognostic factor with an odds ratio of 2.38 (95% CI 1.28-4.41, P = 0.006).

CONCLUSION

CD44⁺ phenotype of cytokeratin-positive cells in blood and bone marrow is an independent prognostic factor in patients with gastric cancer.

[The liquid biopsies: What is their contribution to the management of cancer?]

The « liquid biopsies » are samples of liquids such as blood, urine, spinal fluid that can contain tumor material. Clinical assays have been mainly focused on the peripheral blood containing circulating tumor cells and circulating tumor DNA. The circulating tumor cells are cancer cells released from the primary tumor or recurrences or metastases. They enter into the bloodstream after passing through the vessel wall. It is possible to analyze the circulating tumor cells by means of all cytologic and biomolecular techniques. The free circulating tumor DNA is made of fragments of DNA released by living or necrotic tumor cells proceeded from any place of the organism. The free circulating tumor DNA and DNA from circulating tumor cells show structural rearrangements among which some are therapeutic targets. Many studies showed that circulating tumor cells and circulating tumor DNA analyses are useful in revealing recurrences and tracking therapeutic targets.

Mesenchymal marker and LGR5 expression levels in circulating tumor cells correlate with colorectal cancer prognosis

PURPOSE

The presence of circulating tumor cells (CTCs) has been found to correlate with colorectal cancer (CRC) prognosis, whereas epithelial-mesenchymal transition (EMT) in CTCs has been found to be associated with CRC metastasis. LGR5 is a known target of Wnt signaling and plays an important role in CRC development. The aim of this study was to assess the clinical relevance of EMT and LGR5 expression in CTCs from CRC patients.

METHODS

Sixty-six CRC patients were included in this study. The detection and expression of EMT phenotypes in CTCs from these patients were assessed using CanPatrol™ CTC enrichment and mRNA in situ hybridization (ISH), respectively. LGR5 expression in the CTCs was assessed using mRNA ISH.

RESULTS

CTCs were detected in 86.4% (57/66) of the CRC patients included. Both the numbers of total CTCs and of CTCs displaying a mesenchymal phenotype (M+ CTCs) were found to significantly correlate with advanced disease stages and the occurrence of metastasis (p < 0.05). An adjusted multivariate analysis also indicated that the number of M+ CTCs significantly correlated with the occurrence of metastasis (p = 0.031). Additionally, we found that a high LGR5 expression level significantly correlated with the occurrence of metastasis (p < 0.05). We also found that the presence of ≥ 6 CTCs or ≥ 3 M+ CTCs per 5 ml blood significantly correlated with disease progression (p < 0.05). Patients with ≥ 6 CTCs or ≥ 3 M+ CTCs per 5 ml blood were found to exhibit poorer progression-free survival (PFS) and overall survival (OS) rates (p < 0.05 in all cases). Using Cox regression analyses, we found that only total CTC numbers remained as independent prognostic factors for a worse PFS (p = 0.043).

CONCLUSIONS

From our data we conclude that CTC numbers and EMT phenotypes may serve as prognostic markers for disease progression and metastasis in CRC patients. In addition, we conclude that LGR5 expression in CTCs may serve as a marker for CRC metastasis.

Characterization of potential driver mutations involved in human breast cancer by computational approaches

Breast cancer is the second most frequently occurring form of cancer and is also the second most lethal cancer in women worldwide. A genetic mutation is one of the key factors that alter multiple cellular regulatory pathways and drive breast cancer initiation and progression yet nature of these cancer drivers remains elusive. In this article, we have reviewed various computational perspectives and algorithms for exploring breast cancer driver mutation genes. Using both frequency based and mutational exclusivity based approaches, we identified 195 driver genes and shortlisted 63 of them as candidate drivers for breast cancer using various computational approaches. Finally, we conducted network and pathway analysis to explore their functions in breast tumorigenesis including tumor initiation, progression, and metastasis.

EMT-like circulating tumor cells in ovarian cancer patients are enriched by platinum-based chemotherapy

Background

Assuming that tumor cell dissemination requires a shift to a mesenchymal phenotype, we analyzed the incidence of epithelial-to-mesenchymal-transition (EMT)-like circulating tumor cells (CTCs) in ovarian cancer patients and inquired, how their molecular phenotypes respond to platinum-based chemotherapy and influence outcome.

Results

Before surgery, overall detection rate for epithelial CTCs was 18%. EMT-like CTCs were more frequently observed (30%) and were mutually exclusive to epithelial CTCs in the majority of patients (82%). After chemotherapy, EMT-like CTCs increased up to 52%, accompanied by the “de novo” emergence of PI3Kα+/Twist+ EMT-like CTCs. Before surgery, PI3K+ EMT-like CTCs in combination with epithelial CTCs indicated decreased OS (p = 0.02) and FIGO I-III patients with residual tumor burden after surgery were more likely to be positive for EMT-like CTCs after chemotherapy (p = 0.02). In the latter group, epithelial CTCs alone significantly correlated with decreased PFS and OS (p = 0.02, p = 0.002), supported by an additional inclusion of PI3K+ CTCs (OS, p = 0.001).

Materials and Methods

Blood samples of 91 ovarian cancer patients before surgery and 31 matched samples after adjuvant chemotherapy were evaluated for CTCs with the AdnaTest ovarian cancer and EMT-1, analyzing the epithelial-associated transcripts EpCAM, Muc-1 and CA125 and the EMT-associated transcripts PI3Kα, Akt-2 and Twist.

Conclusions

Platinum-based chemotherapy seems to select for EMT-like CTCs in ovarian cancer patients and provokes a shift towards PI3Kα and Twist expressing CTCs, which may reflect clonal tumor evolution towards therapy resistance. It has to be determined, whether this CTC subgroup may serve as a biomarker to identify patients at high risk.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

Background

We recently showed that the presence of ERCC1⁺CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1⁺CTCs dynamics mirror response to chemotherapy.

Methods

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1⁺CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1⁺CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

Conclusion

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1⁺CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.

Analysis of the hormone receptor status of circulating tumor cell subpopulations based on epithelial-mesenchymal transition: a proof-of-principle study on the heterogeneity of circulating tumor cells

Although the enumeration of circulating tumor cells (CTCs) has been demonstrated to be a prognostic indicator in metastatic breast cancer, the heterogeneous characteristics of CTCs, such as variations in the epithelial-mesenchymal transition (EMT), may limit its broad clinical application. To investigate an uncomplicated and practicable detection approach based on the potential utility of the heterogeneity of CTCs from the standpoint of the EMT phenotype and ER/PR status of CTCs, an analysis was conducted using peripheral blood samples obtained from 28 metastatic breast cancer patients. The CanPatrol CTC enrichment technique was used to identify different CTC subpopulations, including epithelial-dominated CTCs, biophenotypic epithelial/mesenchymal CTCs, and mesenchymal-dominated CTCs, according to epithelial and mesenchymal markers. Furthermore, the hormone receptor (HR) status of each CTC was determined based on the expression levels of three reference genes and was characterized by four levels, which ranged from high-level expression to non-expression. We subsequently concluded that based on EMT phenotypes, the order of different CTC subgroups differed according to the HR expression status of the primary tumor. With respect to the HR status between tissues and CTCs, the variation tendency from high-level expression to non-expression of HR in CTCs was significantly correlated with the HR status of the primary tumor. The findings could provide evidence for the potential application of this uncomplicated and practicable detection approach for prognostic analysis and individualized endocrine therapeutic direction in a real-time manner via confirmation in further large-scale trials.

Circulating tumor cells promote the metastatic colonization of disseminated carcinoma cells by inducing systemic inflammation

Circulating tumor cells (CTCs) have been studied well in the prognosis for malignant diseases as liquid biopsy, but their contribution to tumor metastasis is not clearly defined. Here we report that CTCs could promote the metastatic colonization of disseminated carcinoma cells by inducing systemic inflammation and neutrophil recruitment to pre-metastatic organs. Depletion of neutrophils in vivo could effectively abrogate the promoting effect of CTCs on tumor cell metastasis. In the presence of CTCs, the pro-tumor function of neutrophils was augmented, whereas the antitumor function of neutrophils was suppressed. Mechanically, CTC-derived ligands for TLR2 and TLR4 (TLR2/4) induced the systemic inflammation, thus increasing the production of proinflammatory cytokines such as G-CSF and IL-6 that could induce the conversion of neutrophil function from tumor-suppressing to tumor-promoting. Moreover, CTCs induced the production of endogenous TLR2/4 ligands such as S100A8, S100A9, and SAA3, which may amplify the stimulating effect that induces the expression of proinflammatory cytokines. The promoting effect of CTCs on tumor cell metastasis could be abrogated by suppressing inflammatory response with IL-37, an anti-inflammatory cytokine, or blocking CTC-derived ligands for TLR2/4. Identification of the metastatic axis of CTCs/systemic inflammation/neutrophils may provide potential targets for preventing tumor cell metastasis.

Stem-like plasticity and heterogeneity of circulating tumor cells: current status and prospect challenges in liver cancer

Poor prognosis and high recurrence remain leading causes of primary liver cancerassociated mortality. The spread of circulating tumor cells (CTCs) in the blood plays a major role in the initiation of metastasis and tumor recurrence after surgery. Nevertheless, only a subset of CTCs can survive, migrate to distant sites and establish secondary tumors. Consistent with cancer stem cell (CSC) hypothesis, stem-like CTCs might represent a potential source for cancer relapse and distant metastasis. Thus, identification of stem-like metastasis-initiating CTC-subset may provide useful clinically prognostic information. This review will emphasize the most relevant findings of CTCs in the context of stem-like biology associated to liver carcinogenesis. In this view, the emerging field of stem-like CTCs may deliver substantial contribution in liver cancer field in order to move to personalized approaches for diagnosis, prognosis and therapy.

Circulating and disseminated tumor cells: diagnostic tools and therapeutic targets in motion

Enumeration of circulating tumor cells (CTCs) in peripheral blood with the gold standard CellSearchTM has proven prognostic value for tumor recurrence and progression of metastatic disease. Therefore, the further molecular characterization of isolated CTCs might have clinical relevance as liquid biopsy for therapeutic decision-making and to monitor disease progression. The direct analysis of systemic cancer appears particularly important in view of the known disparity in expression of therapeutic targets as well as epithelial-to-mesenchymal transition (EMT)-based heterogeneity between primary and systemic tumor cells, which all substantially complicate monitoring and therapeutic targeting at present. Since CTCs are the potential precursor cells of metastasis, their in-depth molecular profiling should also provide a useful resource for target discovery. The present review will discuss the use of systemically spread cancer cells as liquid biopsy and focus on potential target antigens.

Circulating cell-free DNA and circulating tumor cells, the "liquid biopsies" in ovarian cancer

Limited understanding of ovarian cancer (OC) genome portrait has hindered the therapeutic advances. The serial monitoring of tumor genotypes is becoming increasingly attainable with circulating cell-free DNA (cf-DNA) and circulating tumor cells (CTCs) emerging as “liquid biopsies”. They represent non-invasive biomarkers and are viable, as they can be isolated from human plasma, serum and other body fluids. Molecular characterization of circulating tumor DNA (ct-DNA) and CTCs offer unique potentials to better understand the biology of metastasis and resistance to therapies. The liquid biopsies may also give innovative insights into the process of rapid and accurate identification, resistant genetic alterations and a real time monitoring of treatment responses. In addition, liquid biopsies are shedding light on elucidating signal pathways involved in invasiveness and metastasis competence; but the detection and molecular characterization of ct-DNA and CTCs are still challenging, since they are rare, and the amount of available samples are very limited. This review will focus on the clinical potential of ct-DNA and CTCs in both the early and advanced diagnosis, prognosis, and in the identification of resistance mutations in OC.

EpCAM-expressing circulating tumor cells in colorectal cancer

BACKGROUND

Several studies have raised the issue of the inadequacy of CellSearch® to detect the entire pool of circulating tumor cells (CTCs) from blood of cancer patients, suggesting that cells expressing low levels of epithelial cell adhesion molecule (EpCAM) are not recognized by the capture reagent. In this exploratory study, we aimed to evaluate the status of EpCAM in CTCs isolated from a group of metastatic colorectal cancer patients, in 40% of whom, CTC had been found to be undetected by the CellSearch® system.

METHODS

CTCs were analyzed using both a microfiltration method (ScreenCell) and CellSearch® in parallel. Furthermore, since EpCAM exists in 2 different variants, we investigated the presence of both its intracellular domain (EpICD) and extracellular domain (EpEX) through immunofluorescence staining of CTCs on filters.

RESULTS

Results from immunofluorescence experiments demonstrated that, overall, EpICD and/or EpEX was expressed in 176 CTCs detected by ScreenCell, while the CellSearch® system was able to capture only 10 CTCs.

CONCLUSIONS

This is the first demonstration that the low sensitivity of CellSearch® to detect CTCs in colorectal cancer patients is not due to the lack of EpCAM.

Gene Expression Signatures in Circulating Tumor Cells Correlate with Response to Therapy in Metastatic Breast Cancer

BACKGROUND

Circulating tumor cells (CTCs) are thought to be an ideal surrogate marker to monitor disease progression in metastatic breast cancer (MBC). We investigated the prediction of treatment response in CTCs of MBC patients on the basis of the expression of 46 genes.

METHODS

From 45 MBC patients and 20 healthy donors (HD), 2 × 5 mL of blood was collected at the time of disease progression (TP0) and at 2 consecutive clinical staging time points (TP1 and TP2) to proceed with the AdnaTest EMT-2/StemCellSelectTM (QIAGEN). Patients were grouped into (a) responder (R) and non-responder (NR) at TP1 and (b) overall responder (OR) and overall non-responder (ONR) at TP2. A 46-gene PCR assay was used for preamplification and high-throughput gene expression profiling. Data were analyzed by use of GenEx (MultiD) and SAS.

RESULTS

The CTC positivity was defined by the four-gene signature (EPCAM, KRT19, MUC1, ERBB2 positivity). Fourteen genes were identified as significantly differentially expressed between CTC+ and CTC− patients (KRT19, FLT1, EGFR, EPCAM, GZMM, PGR, CD24, KIT, PLAU, ALDH1A1, CTSD, MKI67, TWIST1, and ERBB2). KRT19 was highly expressed in CTC+ patients and ADAM17 in the NR at TP1. A significant differential expression of 4 genes (KRT19, EPCAM, CDH1, and SCGB2A2) was observed between OR and ONR when stratifying the samples into CTC+ or CTC−.

CONCLUSIONS

ADAM17 could be a key marker in distinguishing R from NR, and KRT19 was powerful in identifying CTCs.

Sensitive detection of PD-L1 expression on circulating epithelial tumor cells (CETCs) could be a potential biomarker to select patients for treatment with PD-1/PD-L1 inhibitors in early and metastatic solid tumors

BACKGROUND

The current cancer research strongly focuses on immune therapies, where the PD-1, with its ligands plays an important role. It is known that PD-L1 is frequently up-regulated in a number of different cancers and the relevance of this pathway has been extensively studied and therapeutic approaches targeting PD-1 and PD-L1 have been developed. We used a non-invasive, real-time biopsy for determining PD-L1 and PD-L2 expression in CETCs of solid cancer patients.

METHODS

CETCs were determined from blood of 128 patients suffering from breast (72), prostate (27), colorectal (18) and lung (11) cancer. The number of vital CETCs and the expression of PD-L1 and PD-L2 were investigated using the maintrac^® method.

RESULTS

PD-L1 expressing CETCs were detected in 94.5% of breast, 100% of prostate, 95.4% of colorectal and 82% of lung cancer patients whereas only 75% of breast cancer patients had PD-L2 positive CETCs. In the PD-L1 and PD-L2 expressing patients the cell fraction of PD-L1 positive CETCs is significantly higher than the fraction of PD-L2 positive CETCs (54.6% vs. 28.7%; p<0.001). Breast cancer patients with metastatic disease had significantly more PD-L1 positive CETCs as compared to patients without metastasis (median 75% vs. 61.1%; p<0.05).

CONCLUSION

PD-L1 seems to be a major factor in immune evasion and is highly expressed on CETCs regardless of the type of cancer. Monitoring the frequency of PD-L1 positive CETCs could reflect individual patient's response for an anti-PD-1/PD-L1 therapy and may be a promising target of anticancer treatment.

Intratumor Heterogeneity and Circulating Tumor Cell Clusters

Genetic diversity plays a central role in tumor progression, metastasis, and resistance to treatment. Experiments are shedding light on this diversity at ever finer scales, but interpretation is challenging. Using recent progress in numerical models, we simulate macroscopic tumors to investigate the interplay between growth dynamics, microscopic composition, and circulating tumor cell cluster diversity. We find that modest differences in growth parameters can profoundly change microscopic diversity. Simple outwards expansion leads to spatially segregated clones and low diversity, as expected. However, a modest cell turnover can result in an increased number of divisions and mixing among clones resulting in increased microscopic diversity in the tumor core. Using simulations to estimate power to detect such spatial trends, we find that multiregion sequencing data from contemporary studies is marginally powered to detect the predicted effects. Slightly larger samples, improved detection of rare variants, or sequencing of smaller biopsies or circulating tumor cell clusters would allow one to distinguish between leading models of tumor evolution. The genetic composition of circulating tumor cell clusters, which can be obtained from non-invasive blood draws, is therefore informative about tumor evolution and its metastatic potential.

How to study and overcome tumor heterogeneity with circulating biomarkers: The breast cancer case

Breast cancer ranks first among female cancer-related deaths in Western countries. As the primary tumor can often be controlled by surgical resection, the survival of women with breast cancer is closely linked to the incidence of distant metastases. Molecular screening by next generation sequencing highlighted the spatial and temporal heterogeneity of solid tumors as well as the clonal evolution of cancer cells during progression and under treatment pressure. Such findings question whether an optimal assessment of disease progression and a screening for druggable mutations should be based on molecular features of primary or recurrent/metastatic lesions and therefore represent a crucial element for failure or success of personalized medicine. In fact, new targeted therapies may induce only short-term benefit annulled by the emergence of resistant clones with new driver mutations which would need to be rapidly and reliably identified. Serial tissue sampling is therefore essential but, unfortunately, also represents a problem since biopsies from solid lesions, which are invasive and potentially painful and risky, cannot be easily repeatedly sampled, are inaccessible or may not fully reflect tumor heterogeneity. The need to early detect and strike this "moving target" is now directing the scientific community toward liquid biopsy-based biomarkers, which include circulating tumor cells (CTC) and cell-free circulating tumor DNA (ctDNA), can be repeatedly assessed through non-invasive and easy-to-perform procedures and may act as reliable read-outs of functional and molecular features of recurrent/metastatic lesions. In this review we summarize the outcome of CTCs and ctDNA in breast cancer, with special reference on their role on unveiling and overcoming tumor heterogeneity, on their potential relevance for tumor surveillance and monitoring, and for the selection of therapeutic options. Finally, we propose integration between blood-based molecular and clinical approaches for monitoring disease progression according to the specific pattern of recurrence of the most aggressive breast cancer molecular subtypes.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

BACKGROUND

We recently showed that the presence of ERCC1+CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1+CTCs dynamics mirror response to chemotherapy.

METHODS

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1+CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1+CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

CONCLUSION

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1+CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.

ERCC1-expressing circulating tumor cells as a potential diagnostic tool for monitoring response to platinum-based chemotherapy and for predicting post-therapeutic outcome of ovarian cancer

BACKGROUND

We recently showed that the presence of ERCC1+CTCs is an independent predictive biomarker for platinum-resistance and poor prognosis of ovarian cancer. The goal of our current research was to determine how the auxiliary assessment of ERCC1-transcripts influences overall CTC-detection rate. We extended this investigation from an initially predictive setting to paired pre- and post-therapeutic blood analysis in order to see, whether ERCC1+CTCs dynamics mirror response to chemotherapy.

METHODS

65 Paired blood samples (10ml) of primary ovarian cancer patients at primary diagnosis and after chemotherapy were studied for CTCs with the AdnaTest Ovarian Cancer (QIAGEN Hannover GmbH). We analyzed the tumor-associated transcripts EpCAM, MUC-1 and CA-125. ERCC1-transcripts were investigated in a separate approach by singleplex RT-PCR.

RESULTS

Auxiliary assessment of ERCC1-transcripts enhanced the overall CTC-detection rate up to 17%. ERCC1+CTCs (defined as positive for one of the AdnaTest markers plus ERCC1-positivity) were detected in 15% of patients at primary diagnosis and in 12% after chemotherapy. The presence of ERCC1+CTCs after chemotherapy correlated with platinum-resistance (P=0.01), reduced PFS (P=0.0293) and OS (P=0.0008) and their persistence indicated poor post-therapeutic outcome (PFS: P=0.005; OS: P=0.0058). Interestingly, the assessment of ERCC1-transcripts alone was sufficient for the detection of prognostic relevant ERCC1-expressing CTCs.

CONCLUSION

Auxiliary assessment of ERCC1-transcripts expands the phenotypic spectrum of CTC detection and defines an additional overlapping fraction of ERCC1-expressing CTCs, which are potentially selected by platinum-based chemotherapy. Specifically, we suggest that ERCC1+CTCs could additionally be useful as a surrogate for monitoring platinum-based chemotherapy and to assess the post-therapeutic outcome of ovarian cancer.