Thymidylate synthase expression in circulating tumor cells: a new tool to predict 5-fluorouracil resistance in metastatic colorectal cancer patients

Clinical value of circulating tumour cells in evaluating the efficacy of continuous hepatic arterial infusion among colorectal cancer patients

Few studies have been conducted to evaluate the efficacy of HAIC using circulating tumour cells (CTCs). In this study, a total of 100 patients who received HAIC treatment and CTC detection were selected. The results showed that after HAIC treatment, the levels of CTC, carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) decreased. Postoperative progression-free survival (PFS) rates between patients with positive and negative preoperative CTC results, and for CA19-9, CEA were significantly different. The positive rate of CTCs was 61% before chemotherapy and 23% after chemotherapy, and the correlation coefficient between the two was 0.385. Those whose CTC values increased after chemotherapy had shorter PFS rates. CTCs are an independent predictor of recurrence. Patients with CTC-positive results are more susceptible to recurrence. The CTC count in peripheral blood has a close bearing on the postoperative chemotherapy efficacy of patients with CRC and affects patients' PFS.

MiR-548c-3p through suppressing Tyms and Abcg2 increases the sensitivity of colorectal cancer cells to 5-fluorouracil

Background

Colorectal cancer, is one of most prevalent the cancer in the world. 5-Fluorouracil is a standard chemotherapeutic drug while the acquisition of resistance to 5-Fluorouracil is one of the problems during treatment. In this study, we aimed to find the miRNAs that modulate the expression of Tyms and Abcg2 as resistance-inducing genes in the resistant cell lines to 5-Fluorouracil.

Methods

5-Fluorouracil-resistant HCT116 and SW480 cell lines were generated by consecutive treatment of cells with 5-Fluorouracil. This resistance induction was validated by MTT assays. The expression of the Tyms and Abcg2 gene and miR-548c-3p were studied by quantitative real-time PCR in the cell lines.

Results

We hypothesized that miR-548c-3p is targeting Tyms and Abcg2 simultaneously. Increased expression Tyms gene in the two most resistant cell lines derived from HCT116 and all resistant cell lines derived from SW480 except one were seen. Increased expression of Abcg2 was observed in the most resistant HCT116-derived cell line and all resistant cell lines, derived from SW480. In all resistant cell lines, the expression of miR-548c-3p was decreased.

Conclusion

It can be concluded downregulation of miR548c-3p is in line with Tyms and Abcg2 overexpression in resistant cell lines to 5-Fluorouracil.

CD47 Expression in Circulating Tumor Cells and Circulating Tumor Microemboli from Non-Small Cell Lung Cancer Patients Is a Poor Prognosis Factor

Circulating tumor cells (CTCs) and/or circulating tumor microemboli (CTM) from non-small cell lung cancer (NSCLC) patients may be a non-invasive tool for prognosis, acting as liquid biopsy. CTCs interact with platelets through the transforming growth factor-β/transforming growth factor-β receptor type 1 (TGF-β/TGFβRI) forming clusters. CTCs also may express the Cluster of Differentiation 47 (CD47) protein, responsible for the inhibition of phagocytosis, the "don't eat me" signal to macrophages.

OBJECTIVES

To isolate, quantify and analyze CTCs/CTMs from metastatic NSCLC patients, identify TGFβRI/CD47 expression in CTCs/CTMs, and correlate with progression-free survival (PFS).

METHODS

Blood (10 mL) was collected at two time-points: T1 (before the beginning of any line of treatment; T2 (60 days after initial collection). CTCs were isolated using ISET®. Immunocytochemistry was conducted to evaluate TGFβRI/CD47 expression.

RESULTS

45 patients were evaluated. CTCs were observed in 82.2% of patients at T1 (median: 1 CTC/mL; range: 0.33-11.33 CTCs/mL) and 94.5% at T2 (median: 1.33 CTC/mL; 0.33-9.67). CTMs were observed in 24.5% of patients and significantly associated with poor PFS (10 months vs. 17 months for those without clusters; p = 0.05) and disease progression (p = 0.017). CTMs CD47+ resulted in poor PFS (p = 0.041). TGFβRI expression in CTCs/CTMs was not associated with PFS.

CONCLUSION

In this study, we observed that CTC/CTM from NSCLC patients express the immune evasion markers TGFβRI/CD47. The presence of CTMs CD47+ is associated with poor PFS. This was the first study to investigate CD47 expression in CTCs/CTM of patients with NSCLC and its association with poor PFS.

HPV virus and biomarkers of resistance to chemoradiation in circulating tumor cells from patients with squamous cell carcinoma of the anus

Localized anal cancer is mostly represented by squamous cell carcinoma of the anus (SCCA) and is cured in ≥80 % of cases by chemoradiation (CRT). Development of techniques for detection/evaluating circulating tumor cells (CTCs) for diagnosis/ prognosis/response to therapy can change the manner we treat/follow SCCA patients.

OBJECTIVE

to detect CTCs from patients with SCCA and evaluate the presence of HPV virus, p16 expression and markers related to resistance to CRT (RAD23B/ ERCC1/ TYMS) in CTCs at baseline and after CRT.

METHODS

CTCs were isolated/quantified by ISET®, protein expressions were analyzed by immunocytochemistry and HPV DNA was detected by chromogenic in situ hybridization.

RESULTS

We enrolled 15 patients: median age was 61 (43-73) years, the majority was women (10/15). CTCs were detected in all patients at baseline (median= 0.4 (0.4-3.33) CTCs/mL) and in 8/9 patients, after CRT (median= 2.33 (0-7.0) CTCs/mL). DNA from HPV was found in CTCs in 14/15 patients (93.33 %) at baseline and in 7/9 (77.7 %) after treatment. At a median follow-up of 22.20 (1.45-38.55) months, three patients expressed ERCC1 in CTCs after treatment, with one of them having disease recurrence.

CONCLUSION

We showed that detection of HPV in CTCs from patients with non-metastatic SCCA is feasible and appears to be a sensitive diagnostic method. These results may be clinically useful for better monitoring these patients. However, future larger cohorts may demonstrate whether there is any correlation between the presence of HPV and the expression of screening markers for CRT in SCCA.

Cluster of resistance-inducing genes in MCF-7 cells by estrogen, insulin, methotrexate and tamoxifen extracted via NMF

Breast cancer has become a leading cause of death for women as the economy has grown and the number of women in the labor force has increased. Several biomarkers with diagnostic, prognostic, and therapeutic implications for breast cancer have been identified in studies, leading to therapeutic advances. Resistance, on the other hand, is one of clinical practice's limitations. In this paper, we use Nonnegative Matrix Factorization to automatically extract two gene signatures from gene expression profiles of wild-type and resistance MCF-7 cells, which were then investigated further using pathways analysis and proved useful in relating resistance pathways to breast cancer regardless of the stimulus that caused it. A few extracted genes (including MAOA, IL4I1, RRM2, DUT, NME4, and SUMO3) represent new elements in the functional network for resistance in MCF-7 ER+ breast cancer. As a result of this research, a better understanding of how resistance occurs or the pathways that contribute to it may allow more effective therapies to be developed.

Deficient or R273H and R248W Mutations of p53 Promote Chemoresistance to 5-FU via TCF21/CD44 Axis-Mediated Enhanced Stemness in Colorectal Carcinoma

Background: p53 mutations are highly frequent in various human cancers and are reported to contribute to tumor malignance and chemoresistance. In this study, we explored the mechanism by which mutant p53 promotes carcinogenesis and chemoresistance and provided novel insights into cancer therapy.

Materials and methods: A total of 409 patients with colorectal carcinoma from TCGA database were subdivided into two groups according to the p53 status, namely, mutant p53 and wild-type p53, following with GSEA analysis. The differences of the clinicopathologic index were also analyzed. Two HCT116 cell lines containing hot spots at codons R273H and R248W of p53 were constructed based on HCT116 with knockout p53, respectively. Cell viability, mobility, clonogenesis, and stemness were detected by CCK8, transwell migration and invasion, colonogenic, and sphere formation assays. Resistance to 5-FU was examined by live-dead staining and flow cytometry. qPCR, Western blot, and luciferase reporter assay were performed to identify that deficient or mutant p53 promoted chemoresistance of the colorectal carcinoma cell line HCT116 through the TCF21/CD44 signaling pathway, with the following rescue assays by overexpression of TCF21 and knockdown of CD44.

Results: Patients with recurrence harbor a higher frequency of mutant p53 than those without recurrence (p < 0.05). The mutant p53 group developed a larger tumor than the wild-type one. GSEA analysis showed that oncogenic signatures were enriched in the mutant p53 group. Extracellular assays showed that cancer cells with deficient or mutant p53 (R273H and R248W, respectively) promoted colon cancer cell growth, migration, invasion, and stemness. The mutant cancer cells were also observed to be significantly resistant to 5-FU. Xenografts also confirmed that HCT116 cells harboring deficient or mutant p53 promoted cancer growth and 5-FU tolerance. Luciferase reporter assay showed that deficient or mutant p53 R237H and R248W endowed cancer cells with chemoresistance by activating CD44 via repressing the nuclear transcription factor TCF21 expression. Overexpression of TCF21 or knockdown of CD44 could rescue the sensitivity to 5-FU in deficient and mutant p53 HCT116 cell lines.

Conclusion: Our results, for the first time, reveal a novel deficient or mutant p53/TCF21/CD44 signaling pathway which promotes chemoresistance in colorectal carcinoma. The axis could be an effective therapeutic strategy against deficient- or mutant p53-driven chemoresistance.

Visfatin and Resveratrol Differentially Regulate the Expression of Thymidylate Synthase to Control the Sensitivity of Human Colorectal Cancer Cells to Capecitabine Cytotoxicity

Colorectal cancer (CRC) is a highly lethal malignant cancer. Capecitabine, a 5-fluororacil (5-FU) derivate, is its first-line drug, but the resistance of CRC to capecitabine is still the most challenging factor for curing patients. It has been suggested that thymidylate synthase (TYMS) level might affect the capecitabine efficacy in CRC patients, but the mechanism still needs more elucidation. Obesity is a risk factor for CRC. Recently, a correlation between serum visfatin, an obesity-elicited adipokine, and CRC development has been found. Thus, the aim of present study is to examine the visfatin capacity in TYMS expression and in the development of capecitabine resistance of CRC. Moreover, an attractive natural component, i.e., resveratrol, has been proposed in anticancer therapy and has hence been examined in the present study to see its potential capacity in the alleviation of CRC resistance. Our results found that visfatin significantly reduces the CRC sensitivity to capecitabine by controlling the TYMS expression via p38 signaling and Sp1 transcription factor. Moreover, resveratrol could significantly alleviate the visfatin effect on capecitabine-treated CRC cells. These results provided new insights to understand the capecitabine susceptibility of CRC under a visfatin-containing environment and a possible therapeutic application of resveratrol in CRC patients with obesity.

Identification and Validation of TYMS as a Potential Biomarker for Risk of Metastasis Development in Hepatocellular Carcinoma

Metastasis is the major cause of hepatocellular carcinoma (HCC) mortality. Unfortunately, there are few reports on effective biomarkers for HCC metastasis. This study aimed to discover potential key genes of HCC, which could provide new insights for HCC metastasis. GEO (Gene Expression Omnibus) microarray and TCGA (The Cancer Genome Atlas) datasets were integrated to screen for candidate genes involved in HCC metastasis. Differentially expressed genes (DEGs) were screened, and then we performed enrichment analysis of Gene Ontology (GO), together with Kyoto Encyclopedia of Genes and Genomes (KEGG). A protein-protein interaction network was then built and analyzed utilizing STRING and Cytoscape, followed by the identification of 10 hub genes by cytoHubba. Four genes were associated with survival, their prognostic value was verified by prognostic signature analysis. Thymidylate synthase (TYMS) gene was identified as significant HCC metastasis-associated genes after mRNA expression validation and IHC analysis. TYMS silencing in HCC cells remarkedly inhibited growth and invasion. Finally, we found TYMS silencing dramatically decrease DNA synthesis and extracellular matrix (ECM) degradation, resulting in the inhibition of HCC metastasis, indicating TYMS had close associations with HCC development. These findings provided new insights into HCC metastasis and identified candidate gene prognosis signatures for HCC metastasis.

Circulating Tumor Cells in Desmoid Tumors: New Perspectives

Introduction

Desmoid tumor (DT) is a rare neoplasm with high local recurrence rates, composed of fibroblastic cells that are characterized by the expression of key molecules, including the intermediate filament vimentin, cyclooxygenase-2 (COX-2), and nuclear β-catenin, and lack of epithelial markers. Circulating tumor cells (CTCs) isolated from the peripheral blood of patients with sarcomas and other neoplasms can be used as early biomarkers of tumor invasion and dissemination. Moreover, CTCs can also re-colonize their tumors of origin through a process of "tumor self-seeding."

Objectives

We aimed to identify CTCs in the peripheral blood of patients with DT and evaluate their expression of β-catenin, transforming growth factor receptor I (TGF-βRI), COX-2, and vimentin proteins.

Material and Methods

We conducted a prospective study of patients with initial diagnosis or relapsed DT with measurable disease. Blood samples from each patient were processed and filtered by ISET^® (Rarecells, France) for CTC isolation and quantification. The CTC expression of β-catenin, COX-2, TGF-βRI, and vimentin was analyzed by immunocytochemistry (ICC).

Results

A total of 18 patients were included, and all had detectable CTCs. We found a concordance of β-catenin expression in both CTCs and primary tumors in 42.8% (6/14) of cases by using ICC and immunohistochemistry, respectively.

Conclusions

Our study identified a high prevalence of CTCs in DT patients. Concordance of β-catenin expression between primary tumor and CTCs brings new perspectives to assess the dynamics of CTCs in the blood compartment, opening new avenues for studying the biology and behavior of DT. In addition, these results open the possibility of using CTCs to predict DT dynamics at the time of disease progression and treatment. Further studies with larger sample sizes are needed to validate our findings.

A Pilot Study Investigating the Expression Levels of Pluripotency-Associated Genes in Rectal Swab Samples for Colorectal Polyp and Cancer Diagnosis and Prognosis

Change in gene expression is inevitable in cancer development. With more studies demonstrating the contributions of cancer stem cells (CSCs) in colorectal cancer (CRC) development, this study is aimed at investigating whether rectal swab specimen serves as a tool for detection of dysregulation of CSC or stem cell (SC) markers and at evaluating its potential as a new promising screening method for high-risk patients. Expression levels of 15 pluripotency-associated genes were assessed by quantitative PCR in 53 rectal swab specimens referred for endoscopic screening. Dysregulated genes and joint panels based on such genes were examined for their diagnostic potentials for both polyp and CRC. Out of 15 genes, Oct4, CD26, c-MYC, and CXCR4 showed significantly differential expression among normal, polyp, and CRC patients. A panel of Oct4 and CD26 showed an AUC value of 0.80 (p = 0.003) in identifying CRC patients from polyp/normal subjects, with sensitivity and specificity of 84.6% and 69.2%. A panel of c-MYC and CXCR4 achieved CRC/polyp identification with an AUC value of 0.79 (p = 0.002), with a sensitivity of 82.8% and specificity of 80.0%. The sensitivity for polyp and CRC was 80.0% and 85.7%, respectively. Further analysis showed that higher c-MYC and CXCR4 level was detected in normal subjects who developed polyps after 5-6 years, in comparison with subjects with no lesion developed, and the AUC of the c-MYC and CXCR4 panel increased to 0.88 (p < 0.001), with sensitivity and specificity of 84.4% and 92.3%, respectively, when these patients were included in the polyp group. This study suggests that the Oct4 and CD26 panel is a promising biomarker for distinguishing CRC from normal and polyp patients, whereas the c-MYC and CXCR4 panel may identify polyp and CRC from normal individuals.

Baseline and Kinetic Circulating Tumor Cell Counts Are Prognostic Factors in a Prospective Study of Metastatic Colorectal Cancer

The discovery of predictive biomarkers in metastatic colorectal cancer (mCRC) is essential to improve clinical outcomes. Recent data suggest a potential role of circulating tumor cells (CTCs) as prognostic indicators. We conducted a follow-on analysis from a prospective study of consecutive patients with mCRC. CTC analysis was conducted at two timepoints: baseline (CTC1; before starting chemotherapy), and two months after starting treatment (CTC2). CTC isolation/quantification were completed by ISET^® (Rarecells, France). CTC expressions of drug resistance-associated proteins were evaluated. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan–Meier method. Seventy-five patients were enrolled from May 2012 to May 2014. A CTC1 cut-off of >1.5 CTCs/mL was associated with an inferior median OS compared to lower values. A difference of CTC2−CTC1 > 5.5 CTCs/mL was associated with a reduced median PFS. By multivariate analysis, CTC1 > 1.5 CTCs/mL was an independent prognostic factor for worse OS. Multi-drug resistance protein-1 (MRP-1) expression was associated with poor median OS. CTC baseline counts, kinetics, and MRP-1 expression were predictive of clinical outcomes. Larger studies are warranted to explore the potential clinical benefit of treating mCRC patients with targeted therapeutic regimens guided by CTC findings.

TRIM Proteins in Colorectal Cancer: TRIM8 as a Promising Therapeutic Target in Chemo Resistance

Colorectal cancer (CRC) represents one of the most widespread forms of cancer in the population and, as all malignant tumors, often develops resistance to chemotherapies with consequent tumor growth and spreading leading to the patient’s premature death. For this reason, a great challenge is to identify new therapeutic targets, able to restore the drugs sensitivity of cancer cells. In this review, we discuss the role of TRIpartite Motifs (TRIM) proteins in cancers and in CRC chemoresistance, focusing on the tumor-suppressor role of TRIM8 protein in the reactivation of the CRC cells sensitivity to drugs currently used in the clinical practice. Since the restoration of TRIM8 protein levels in CRC cells recovers chemotherapy response, it may represent a new promising therapeutic target in the treatment of CRC.

Molecular determinants of response to 5-fluorouracil-based chemotherapy in colorectal cancer: The undisputable role of micro-ribonucleic acids

5-flurouracil (5-FU)-based chemotherapy is the main pharmacological therapy for advanced colorectal cancer (CRC). Despite significant progress in the treatment of CRC during the last decades, 5-FU drug resistance remains the most important cause of failure in CRC therapy. Resistance to 5-FU is a complex and multistep process. Different mechanisms including microsatellite instability, increased expression level of key enzyme thymidylate synthase and its polymorphism, increased level of 5-FU-activating enzymes and mutation of TP53 are proposed as the main determinants of resistance to 5-FU in CRC cells. Recently, micro-ribonucleic acids (miRNA) and their alterations were found to have a crucial role in 5-FU resistance. In this regard, the miRNA-mediated mechanisms of 5-FU drug resistance reside among the new fields of pharmacogenetics of CRC drug response that has not been completely discovered. Identification of the biological markers that are related to response to 5-FU-based chemotherapy is an emerging field of precision medicine. This approach will have an important role in defining those patients who are most likely to benefit from 5-FU-based chemotherapy in the future. Thereby, the identification of 5-FU drug resistance mechanisms is an essential step to predict and eventually overcome resistance. In the present comprehensive review, we will summarize the latest knowledge regarding the molecular determinants of response to 5-FU-based chemotherapy in CRC by emphasizing the role of miRNAs.

Identification of TYMS as a promoting factor of retroperitoneal liposarcoma progression: Bioinformatics analysis and biological evidence

Retroperitoneal liposarcoma (RLPS) is one of the most common types of retroperitoneal sarcomas, and has a high recurrence rate. There is an urgent need to further explore its pathogenesis and develop more effective treatment strategies. The aim of the present study was to identify potential driver genes of RLPS through bioinformatics analysis and molecular biology to elucidate potential targets that are suitable for further analysis for the treatment of RLPS. Differentially expressed genes (DEGs) between liposarcoma and normal fatty (NF) tissues were identified based on microarray data through bioinformatics analysis, and thymidylate synthase (TYMS) was selected from the DEGs, based on high content screening (HCS). TYMS expression was evaluated in RLPS tumor tissues and cell lines. A total of 21 RLPS tissues and 10 NF frozen tissues were used for reverse transcription-quantitative PCR, and 47 RLPS formalin-fixed specimens were used for immunohistochemical analysis. The effect of TYMS downregulation on cell proliferation, apoptosis, cell cycle progression, and cell migration and invasion were evaluated using lentivirus-mediated short hairpin RNA. The underlying mechanisms of TYMS in RLPS were examined by protein microarray and verified by western blotting. A total of 855 DEGs were identified. TYMS knockdown had the most notable effect on the proliferative capacity of RLPS cells according to the HCS results. TYMS mRNA expression levels were higher in RLPS tissues compared with NF tissues (P<0.001). TYMS expression was higher in high-grade RLPS tissues compared with low-grade RLPS tissues (P=0.003). The patients with positive TYMS expression had a worse overall survival (OS) and disease-free survival (DFS) compared with the patients with negative TYMS expression (OS, P=0.024; DFS, P=0.030). The knockdown of TYMS reduced proliferation, promoted apoptosis, facilitated cell cycle progression from G₁ to S phase, and reduced cell migration and invasion of RLPS cells. Protein microarray analysis and western blotting showed that the Janus Kinase/Signal transducers and activators of transcription pathway was downregulated following TYMS knockdown. In conclusion, TYMS expression is upregulated in RLPS tissues, and downregulation of TYMS reduces RLPS progression.

Proteomic investigations into resistance in colorectal cancer

Introduction: Despite advances in screening and treatment options, colorectal cancer (CRC) remains one of the most prevalent and lethal cancer subtypes. Resistance to cytotoxic or targeted therapy has remained a constant challenge to the treatment and long-term management of patients, attracting intense worldwide investigation since the 1950s. Through extensive investigations into the proteomic mechanisms and functions that convey resistance to therapy/s, researchers have become able to implicate alterations in several signaling pathways that provide and sustain resistance to treatment.Areas covered: In this review, we summarize how protein alterations are associated with resistance to therapy, with particular emphasis on CRC. An overview of the mechanisms of therapeutic resistance is described, highlighting recent studies which endeavor to elucidate the proteomic changes that are associated with the acquisition and promulgation of therapeutic resistance.Expert opinion: While cancers such as CRC have been intensively studied for decades, unresponsiveness and the resistance to therapy remain critical obstacles in the treatment of patients. Due to the inherent biological and clinical heterogeneity of individual CRCs, proteomic methods stand to become powerful tools to provide biological insights that may guide therapeutic strategies with the ultimate goal of refining emergent immunotherapeutic treatments.

Promising Colorectal Cancer Biomarkers for Precision Prevention and Therapy

Colorectal cancer (CRC) has been ranked as the third most prevalent cancer worldwide. Indeed, it represents 10.2% of all cancer cases. It is also the second most common cause of cancer mortality, and accounted for about 9.2% of all cancer deaths in 2018. Early detection together with a correct diagnosis and staging remains the most effective clinical strategy in terms of disease recovery. Thanks to advances in diagnostic techniques, and improvements of surgical adjuvant and palliative therapies, the mortality rate of CRC has decreased by more than 20% in the last decade. Cancer biomarkers for the early detection of CRC, its management, treatment and follow-up have contributed to the decrease in CRC mortality. Herein, we provide an overview of molecular biomarkers from tumor tissues and liquid biopsies that are approved for use in the CRC clinical setting for early detection, follow-up, and precision therapy, and of biomarkers that have not yet been officially validated and are, nowadays, under investigation.

Baseline circulating stem-like cells predict survival in patients with metastatic breast Cancer

Background

Circulating tumor cells (CTCs) are associated with breast cancer prognosis. Research is limited regarding the role of circulating cancer stem-like cells (cCSCs) considering the treatment response and survival among patients with metastatic breast cancer. Accordingly, we performed this prospective study to clarify the prognostic significance of baseline cCSCs for metastatic breast cancer in terms of first-line chemotherapy.

Methods

Between April 2014 and January 2016, we prospectively enrolled 48 patients with stage IV breast invasive ductal carcinoma who underwent first-line chemotherapy. We identified and analyzed CTCs and cCSCs by using a protocol based on negative selection and flow cytometry before chemotherapy. CTCs were identified as EpCAM⁺Hoechst⁺CD45^– cells and cCSCs as CD133⁺EpCAM⁺Hoechst⁺CD45^– cells. cCSCs were expressed as a percentage of CTCs. The associations between CTCs, cCSCs, and the clinicopathological variables that were predictive of the treatment response and survival outcome were analyzed using univariate and multivariate analyses.

Results

We identified CTCs in all the enrolled patients, with a median number of 33.9/mL CTCs. CSCs were isolated in 97.9% of the patients; the median percentage of cCSCs was 14.7%. A high baseline level of cCSCs was correlated with an inferior tumor response rate (54.2% vs. 95.8%, p < 0.001), overall survival (OS; median: 27.7 months vs. not reached, p < 0.001), and progression-free survival (PFS; median: 5.7 vs. 18.0 months, p < 0.001). Multivariate analysis revealed that along with other clinical variables, baseline cCSCs remained an independent prognostic factor for OS and PFS.

Conclusions

Baseline cCSCs predict the treatment response as well as survival in patients with metastatic breast cancer undergoing first-line chemotherapy. Therefore, the measurement of cCSCs may assist in identifying early cancer treatment response and prognosis.

TYMS presents a novel biomarker for diagnosis and prognosis in patients with pancreatic cancer

Pancreatic cancer is one of the most malignant tumors worldwide. DNA replication plays a critical role in the occurrence and development of pancreatic cancer. TYMS encodes thymidylate synthase, which is important for DNA synthesis. The TYMS gene has been assessed in some tumors. However, the specific role of TYMS in pancreatic cancer has not been identified. This study was designed to clarify the diagnostic and prognostic significance of TYMS in pancreatic cancer.The Cancer Genome Atlas (TCGA) database was used to compare TYMS expression in pancreatic cancer, and ROC curve analysis was used to investigate its diagnostic value. The correlation between clinical characteristics and TYMS expression was analyzed, and the prognostic value of TYMS expression in the patients with pancreatic cancer was assessed by Kaplan-Meier curves and Cox analysis.TYMS was upregulated in pancreatic cancer and associated with poor overall survival (OS) and recurrence-free survival (RFS). Univariate and multivariate survival analysis demonstrated that TYMS is an independent risk factor for OS and RFS in patients with pancreatic cancer.The upregulation of TYMS in pancreatic cancer leads to unfavorable OS and RFS in patients, and represents a diagnostic and prognostic biomarker for patients with pancreatic cancer.

Effect of FOLFOX on minimal residual disease in Stage III colon cancer and risk of relapse

Introduction

25% of Stage III colon cancer patients relapse within 5 years due to minimal residual disease (MRD) not eliminated by surgery and chemotherapy. We hypothesise that sub-types of MRD, defined by circulating tumour cells (CTCs) and bone marrow micro-metastasis (mM) have different types and kinetics of relapse.

Patients and Methods

One month of curative surgery and 1 month after completing six cycles of FOLFOX chemotherapy blood and bone marrow samples were taken to detect CTCs and mM using immunocytochemistry with anti-carcino-embryonic antigen (CEA). Follow up was up to 5 years or disease progression defined as new images on CT scanning. Survival curves using Kaplan–Meier (KM) and Restricted Mean Survival Time (RMST) were calculated for three prognostic groups: CTC and mM negative, CTC negative mM positive, and CTC positive.

Results

76 patients (39 men) participated, mean age 67 years, median follow-up 3.6 years. The response to chemotherapy was heterogeneous and MRD pre-treatment did not predict response to therapy. Of 21 patients MRD (−), 20 remained MRD negative and one patient became mM (+); of 21 patients mM (+), 10 became MRD (−), 8 remained the same and 3 became CTC (+); of the 34 CTC positive, 8 became MRD (−), 8 with only mM, and 18 remained positive.

After chemotherapy, 38 patients were negative for CTC and mM, 17 were positive for only mM, and 21 for CTCs. For the whole cohort, the 5 year KM was 58%, the median survival was not reached. For the three prognostic groups, the KM 5-year survivals were 87%, 58%, and 4%, respectively, the median survival for patients MRD negative and mM only was not reached. RMST for the whole cohort was 3.6 years, for the three prognostic groups the RMST was 4.6 years, 4.0 years, and 1.5 years, respectively. Serum CEA was significantly higher pre-surgery in the CTC positive group. There were no significant differences with respect to age or sex between the three groups.

Conclusions

MRD subtypes pre-chemotherapy did not predict treatment response. Post-chemotherapy MRD subtypes were associated with the pattern of failure and time to failure. MRD negative patients had an excellent prognosis with 87% disease-free survival at 5 years. Those with only mM had a similar outcome up to 2 years and then were at increasing risk of late failure. Patients who were CTC positive had a high risk of early failure. MRD subclassification may be useful to define the risk of relapse in Stage III colon cancer patients and warrants further studies with a larger number of patients.

Molecular and Kinetic Analyses of Circulating Tumor Cells as Predictive Markers of Treatment Response in Locally Advanced Rectal Cancer Patients

Neoadjuvant chemoradiation (NCRT) followed by total mesorectal excision is the standard treatment for locally advanced rectal cancer (LARC). To justify a non-surgical approach, identification of pathologic complete response (pCR) is required. Analysis of circulating tumor cells (CTCs) can be used to evaluate pCR. We hypothesize that monitoring of thymidylate synthase (TYMS) and excision repair protein, RAD23 homolog B (RAD23B), can be used to predict resistance to chemotherapy/radiotherapy. Therefore, the aims of this study were to analyze CTCs from patients with LARC who underwent NCRT plus surgery for expression of TYMS/RAD23B and to evaluate their predictive value. Blood samples from 30 patients were collected prior to NCRT (S1) and prior to surgery (S2). CTCs were isolated and quantified by ISET^®, proteins were analyzed by immunocytochemistry, and TYMS mRNA was detected by chromogenic in situ hybridization. CTC counts decreased between S1 and S2 in patients exhibiting pCR (p = 0.02) or partial response (p = 0.01). Regarding protein expression, TYMS was absent in 100% of CTCs from patients with pCR (p = 0.001) yet was expressed in 83% of non-responders at S2 (p < 0.001). Meanwhile, RAD23B was expressed in CTCs from 75% of non-responders at S1 (p = 0.01) and in 100% of non-responders at S2 (p = 0.001). Surprisingly, 100% of non-responders expressed TYMS mRNA at both timepoints (p = 0.001). In addition, TYMS/RAD23B was not detected in the CTCs of patients exhibiting pCR (p = 0.001). We found 83.3% of sensitivity for TYMS mRNA at S1 (p = 0.001) and 100% for TYMS (p = 0.064) and RAD23B (p = 0.01) protein expression at S2. Thus, TYMS mRNA and/or TYMS/RAD23B expression in CTCs, as well as CTC kinetics, have the potential to predict non-response to NCRT and avoid unnecessary radical surgery for LARC patients with pCR.

Drug resistance and new therapies in colorectal cancer

Colorectal cancer (CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo- and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo- and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibody-drug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.

Expression and clinical relevance of epithelial and mesenchymal markers in circulating tumor cells from colorectal cancer

Circulating tumor cells (CTCs) with phenotypic hallmarks of epithelial-mesenchymal transition (EMT) reportedly contribute to tumor metastasis in different cancer types. We therefore evaluated the expression of EMT markers in CTCs obtained from a large cohort of Chinese patients with colorectal cancer (CRC) and investigated their clinical relevance. The CanPatrol^TM CTC enrichment technique was used to isolate and classify CTCs. CTCs were detected in 1046 of 1203 patients (86.9%), and three phenotypes were identified based on the expression of epithelial and mesenchymal markers: epithelial CTCs, biophenotypic (epithelial/mesenchymal) CTCs, and mesenchymal CTCs. Total CTC numbers positively correlated with both clinical stage and lymph node metastasis and distant metastasis. Furthermore, both biophenotypic and mesenchymal, but not epithelial, CTCs, correlated with the above parameters, suggesting CTCs displaying a mesenchymal phenotype denote more aggressive disease and metastatic potential. This is the first study to demonstrate a significant correlation between CTCs displaying a mesenchymal phenotype and both clinical stage and metastasis in a large cohort of patients with CRC. Our findings suggest that assessment of not only epithelial, but also mesenchymal markers in CTC analyses may offer valuable assistance for tumor staging and metastasis evaluation in patients with CRC.

Circulating Tumor Cells as Cancer Biomarkers in the Clinic

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

Integrating TYMS, KRAS and BRAF testing in patients with metastatic colorectal cancer

AIM

To investigate the impact of thymidylate synthase (TYMS), KRAS and BRAF in the survival of metastatic colorectal cancer (mCRC) patients treated with chemotherapy.

METHODS

Clinical data were collected retrospectively from records of consecutive patients with mCRC treated with fluoropyrimidine-based chemotherapy from 1/2005 to 1/2007. Formalin-fixed paraffin-embedded tissues were retrieved for analysis. TYMS genotypes were identified with restriction fragment analysis PCR, while KRAS and BRAF mutation status was evaluated using real-time PCR assays. TYMS gene polymorphisms of each of the 3’ untranslated region (UTR) and 5’UTR were classified into three groups according to the probability they have for high, medium and low TYMS expression (and similar levels of risk) based on evidence from previous studies. Univariate and multivariate survival analyses were performed.

RESULTS

The analysis recovered 89 patients with mCRC (46.1% de novo metastatic disease and 53.9% relapsed). Of these, 46 patients (51.7%) had colon cancer and 43 (48.3%) rectal cancer as primary. All patients were treated with fluoropyrimidine-based chemotherapy (5FU or capecitabine) as single-agent or in combination with irinotecan or/and oxaliplatin or/and bevacizumab. With a median follow-up time of 14.8 mo (range 0-119.8), 85 patients (95.5%) experienced disease progression, and 63 deaths (70.8%) were recorded. The 3-year and 5-year OS rate was 25.4% and 7.7% while the 3-year progression-free survival rate was 7.1%. Multivariate analysis of TYMS polymorphisms, KRAS and BRAF with clinicopathological parameters indicated that TYMS 3’UTR polymorphisms are associated with risk for disease progression and death (P < 0.05 and P < 0.03 respectively). When compared to tumors without any del allele (genotypes ins/ins and ins/loss of heterozygosity (LOH) linked with high TYMS expression) tumors with del/del genotype (low expression group) and tumors with ins/del or del/LOH (intermediate expression group) have lower risk for disease progression (HR = 0.432, 95%CI: 0.198-0.946, P < 0.04 and HR = 0.513, 95%CI: 0.287-0.919, P < 0.03 respectively) and death (HR = 0.366, 95%CI: 0.162-0.827, P < 0.02 and HR = 0.559, 95%CI: 0.309-1.113, P < 0.06 respectively). Additionally, KRAS mutation was associated independently with the risk of disease progression (HR = 1.600, 95%CI: 1.011-2.531, P < 0.05). The addition of irinotecan in 1^st line chemotherapy was associated independently with lower risk for disease progression and death (HR = 0.600, 95%CI: 0.372-0.969, P < 0.04 and HR = 0.352, 95%CI: 0.164-0.757, P < 0.01 respectively).

CONCLUSION

The TYMS genotypes ins/ins and ins/LOH associate with worst prognosis in mCRC patients under fluoropyrimidine-based chemotherapy. Large prospective studies are needed for validation of our findings.

Circulating miR-1826 in plasma correlates with circulating tumor cells and is a prognostic marker in colorectal cancer

Our previous study showed that miR-1826 was a newly identified oncogenic non-coding RNA in colorectal cancer. But the potential relationship between miR-1826 and tumor metastasis has not been fully elucidated. The purpose of this study was to evaluate the clinical significance of circulating miR-1826 and its possible associations with circulating tumor cells in colorectal cancer. Our results first found that serum miR-1826 was significantly upregulated in colorectal cancer patients, compared with that in healthy volunteers ( p = 0.003). Similar results were also found in colorectal cancer with distant metastasis ( p = 0.001) and advanced colorectal cancer ( p < 0.001) patients, respectively. Clinicopathological analysis implied that circulating miR-1826 was positively associated with pT stage ( p = 0.026), lymphatic metastasis ( p = 0.034), distant metastasis ( p = 0.012), and tumor-node-metastasis stage ( p = 0.020). Besides, our univariate and multivariate analyses demonstrated that high serum miR-1826 expression could act as a prognostic and independent factor for overall survival of colorectal cancer patients ( p < 0.05), which led to a poorer 5-year overall survival rate ( p = 0.025). The area under the curve value of circulating miR-1826 was up to 0.848 ± 0.043, which strongly suggested serum miR-1826 as an effective diagnostic biomarker in colorectal cancer patients ( p < 0.001). Our subsequent experiments demonstrated that patients with high level of circulating tumor cells showed a higher level of miR-1826 expression, compared with the circulating tumor cell-negative patients ( p = 0.011). Similar results also showed that the amount of circulating tumor cells in high miR-1826 group was significantly higher than that in low miR-1826 group ( p = 0.001). Furthermore, the relationship between serum miR-1826 and circulating tumor cells was analyzed using SPSS software and a significant logarithmic relationship was found, which meant that circulating miR-1826 closely correlated with the amount of circulating tumor cells in colorectal cancer patient serum ( r = 0.283, p < 0.01). Our findings strongly suggested that serum miR-1826 could serve as an effective and non-invasive biomarker for diagnosis and prognosis of colorectal cancer. Circulating miR-1826 may be an important target in colorectal cancer therapy.

E-cadherin: A potential biomarker of colorectal cancer prognosis

Colorectal cancer (CRC) is a common and lethal disease. It is the third most common type of cancer in the world, behind lung and breast cancer, with almost 1.4 million new cases diagnosed in 2012. The risk of developing CRC is influenced by environmental and genetic factors. Adenocarcinomas comprise the vast majority (98%) of CRCs. A patient's likelihood of survival is associated with the tumor stage at the time of diagnosis. With regular screening, CRC can be identified early, when treatment is the most effective. However, CRC is typically asymptomatic until the advanced stages. The combination of the absence of symptoms and current screening methodology results in a significant number of patients being diagnosed in advanced stages. The purpose of the present review is to discuss and summarize the biomarkers linked to CRC progression, particularly the controversial E-cadherin, which is a calcium-dependent cell-cell adhesion molecule involved in the mesenchymal-epithelial transition.

Challenges in enumeration of CTCs in breast cancer using techniques independent of cytokeratin expression

INTRODUCTION

Given the current postulated plasticity between epithelial and mesenchymal states of migratory cancer cells the detection of non-epithelial CTCs is an important scientific and clinical goal.

METHODS

We used the filtration-based ISET technology to enrich circulating tumour cells (CTCs) in early breast cancer blood samples and identify them using a morphology-based immunocytochemistry (ICC) approach.

RESULTS

We found greater numbers of putative CTCs by this approach than by the cytokeratin-based CellSearch technology, but a high number of CTC false positives were identified in healthy volunteer samples which were not reduced in successive blood draws. Preliminary work using an oestrogen receptor (ER)-based multiplex ICC method in metastatic breast cancer ISET samples indicated a low number of ER+ CTCs even at this advanced stage.

CONCLUSIONS

This work highlights the challenges in enumerating CTCs without conventional epithelial markers.

New frontiers in the treatment of colorectal cancer: Autophagy and the unfolded protein response as promising targets

Colorectal cancer (CRC), despite numerous therapeutic and screening attempts, still remains a major life-threatening malignancy. CRC etiology entails both genetic and environmental factors. Macroautophagy/autophagy and the unfolded protein response (UPR) are fundamental mechanisms involved in the regulation of cellular responses to environmental and genetic stresses. Both pathways are interconnected and regulate cellular responses to apoptotic stimuli. In this review, we address the epidemiology and risk factors of CRC, including genetic mutations leading to the occurrence of the disease. Next, we discuss mutations of genes related to autophagy and the UPR in CRC. Then, we discuss how autophagy and the UPR are involved in the regulation of CRC and how they associate with obesity and inflammatory responses in CRC. Finally, we provide perspectives for the modulation of autophagy and the UPR as new therapeutic options for CRC treatment.

Prognostic value of circulating tumor cells in esophageal cancer

AIM

To perform a meta-analysis of the related studies to assess whether circulating tumor cells (CTCs) can be used as a prognostic marker of esophageal cancer.

METHODS

PubMed, Embase, Cochrane Library and references in relevant studies were searched to assess the prognostic relevance of CTCs in patients with esophageal cancer. The primary outcome assessed was overall survival (OS). The meta-analysis was performed using the random effects model, with hazard ratio (HR), risk ratio (RR) and 95% confidence intervals (95%CIs) as effect measures.

RESULTS

Nine eligible studies were included involving a total of 911 esophageal cancer patients. Overall analyses revealed that CTCs-positivity predicted disease progression (HR = 2.77, 95%CI: 1.75-4.40, P < 0.0001) and reduced OS (HR = 2.67, 95%CI: 1.99-3.58, P < 0.00001). Further subgroup analyses demonstrated that CTCs-positive patients also had poor OS in different subsets. Moreover, CTCs-positivity was also significantly associated with TNM stage (RR = 1.48, 95%CI: 1.07-2.06, P = 0.02) and T stage (RR = 1.44, 95%CI: 1.13-1.84, P = 0.003) in esophageal cancer.

CONCLUSION

Detection of CTCs at baseline indicates poor prognosis in patients with esophageal cancer. However, this finding relies on data from observational studies and is potentially subject to selection bias. Prospective trials are warranted.

Technical Insights into Highly Sensitive Isolation and Molecular Characterization of Fixed and Live Circulating Tumor Cells for Early Detection of Tumor Invasion

Circulating Tumor Cells (CTC) and Circulating Tumor Microemboli (CTM) are Circulating Rare Cells (CRC) which herald tumor invasion and are expected to provide an opportunity to improve the management of cancer patients. An unsolved technical issue in the CTC field is how to obtain highly sensitive and unbiased collection of these fragile and heterogeneous cells, in both live and fixed form, for their molecular study when they are extremely rare, particularly at the beginning of the invasion process. We report on a new protocol to enrich from blood live CTC using ISET^® (Isolation by SizE of Tumor/Trophoblastic Cells), an open system originally developed for marker-independent isolation of fixed tumor cells. We have assessed the impact of our new enrichment method on live tumor cells antigen expression, cytoskeleton structure, cell viability and ability to expand in culture. We have also explored the ISET^®in vitro performance to collect intact fixed and live cancer cells by using spiking analyses with extremely low number of fluorescent cultured cells. We describe results consistently showing the feasibility of isolating fixed and live tumor cells with a Lower Limit of Detection (LLOD) of one cancer cell per 10 mL of blood and a sensitivity at LLOD ranging from 83 to 100%. This very high sensitivity threshold can be maintained when plasma is collected before tumor cells isolation. Finally, we have performed a comparative next generation sequencing (NGS) analysis of tumor cells before and after isolation from blood and culture. We established the feasibility of NGS analysis of single live and fixed tumor cells enriched from blood by our system. This study provides new protocols for detection and characterization of CTC collected from blood at the very early steps of tumor invasion.

Application of optically-induced-dielectrophoresis in microfluidic system for purification of circulating tumour cells for gene expression analysis- Cancer cell line model

Circulating tumour cells (CTCs) in a blood circulation system are associated with cancer metastasis. The analysis of the drug-resistance gene expression of cancer patients' CTCs holds promise for selecting a more effective therapeutic regimen for an individual patient. However, the current CTC isolation schemes might not be able to harvest CTCs with sufficiently high purity for such applications. To address this issue, this study proposed to integrate the techniques of optically induced dielectrophoretic (ODEP) force-based cell manipulation and fluorescent microscopic imaging in a microfluidic system to further purify CTCs after the conventional CTC isolation methods. In this study, the microfluidic system was developed, and its optimal operating conditions and performance for CTC isolation were evaluated. The results revealed that the presented system was able to isolate CTCs with cell purity as high as 100%, beyond what is possible using the previously existing techniques. In the analysis of CTC gene expression, therefore, this method could exclude the interference of leukocytes in a cell sample and accordingly contribute to higher analytical sensitivity, as demonstrated in this study. Overall, this study has presented an ODEP-based microfluidic system capable of simply and effectively isolating a specific cell species from a cell mixture.

Circulating Tumor Cells and Circulating Tumor DNA: Challenges and Opportunities on the Path to Clinical Utility

Recent technological advances have enabled the detection and detailed characterization of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) in blood samples from patients with cancer. Often referred to as a "liquid biopsy," CTCs and ctDNA are expected to provide real-time monitoring of tumor evolution and therapeutic efficacy, with the potential for improved cancer diagnosis and treatment. In this review, we focus on these opportunities as well as the challenges that should be addressed so that these tools may eventually be implemented into routine clinical care.

Circulating Tumour Cells as an Independent Prognostic Factor in Patients with Advanced Oesophageal Squamous Cell Carcinoma Undergoing Chemoradiotherapy

The role of circulating tumour cells (CTCs) in advanced oesophageal cancer (EC) patients undergoing concurrent chemoradiotherapy (CCRT) remains uncertain. A negative selection protocol plus flow cytometry was validated to efficiently identify CTCs. The CTC number was calculated and analysed for survival impact. The protocol’s efficacy in CTC identification was validated with a recovery rate of 44.6 ± 9.1% and a coefficient of variation of 20.4%. Fifty-seven patients and 20 healthy donors were enrolled. Initial staging, first response to CRT, and surgery after CRT were prognostic for overall survival, with P values of <0.0001, <0.0001, and <0.0001, respectively. The CTC number of EC patients is significantly higher (P = 0.04) than that of healthy donors. Multivariate analysis for disease-specific progression-free survival showed that surgery after response to CCRT, initial stage, and CTC number (≥21.0 cells/mL) played independent prognostic roles. For overall survival, surgery after CCRT, performance status, initial stage, and CTC number were significant independent prognostic factors. In conclusion, a negative selection plus flow cytometry protocol efficiently detected CTCs. The CTC number before CCRT was an independent prognostic factor in patients with unresectable oesophageal squamous cell carcinoma. Further large-scale prospective studies for validation are warranted.

MRP1 expression in CTCs confers resistance to irinotecan-based chemotherapy in metastatic colorectal cancer

Circulating tumor cells are important markers of tumor progression and can reflect tumor behavior in metastatic colorectal cancer (mCRC). Identification of proteins that confer resistance to treatment is an important step to predict response and better selection of treatment for patients. Multidrug resistance-associated protein 1 (MRP1) and Multidrug resistance-associated protein 4 (MRP4) play a role in irinotecan-resistance, and Excision Repair Cross-Complementation group 1 (ERCC1) expression can confer resistance to platinum compounds. Here, we included 34 patients with mCRC and most of them received FOLFIRI or FOLFOX chemotherapy (91.1%). CTCs were isolated by ISET(®) Technology and identified in 30 patients (88.2%), with a median of 2.0 CTCs/mL (0-31.0). We analyzed the immunocytochemical expression of MRP1, MRP4 and ERCC1 only in patients who had previously detectable CTCs, accordingly to treatment received (n = 19, 15 and 13 patients, respectively). Among patients treated with irinotecan-based chemotherapy, 4 out of 19 cases with MRP1 positive CTCs showed a worse progression free survival (PFS) in comparison to those with MRP1 negative CTCs (2.1 months vs. 9.1 months; p = 0.003). None of the other proteins studied in CTCs had significant association with PFS. We analyzed also histological sections of primary tumors and metastases by immunohistochemistry, and found no association with clinicopathological characteristics or with PFS. Our results show MRP1 as a potential biomarker of resistance to treatment with irinotecan when found in CTCs from mCRC patients. This is a small proof-of-principle study and these early findings need to be validated in a larger cohort of patients.

Clinical evaluation of a novel microfluidic device for epitope-independent enrichment of circulating tumour cells in patients with small cell lung cancer

Circulating tumour cells (CTCs) have potential utility as minimally-invasive biomarkers to aid cancer treatment decision making. However, many current CTC technologies enrich CTCs using specific surface epitopes that do not necessarily reflect CTC heterogeneity. Here we evaluated the epitope-independent Parsortix system which enriches CTCs based on size and rigidity using both healthy normal volunteer blood samples spiked with tumour cells and blood samples from patients with small cell lung cancer (SCLC). Blood samples were maintained unfractionated at room temperature for up to 4 days followed by plasma removal for circulating free DNA (cfDNA) isolation and direct application of the remaining cell component to the Parsortix system. For tumour cells expressing the EpCAM cell surface marker the numbers of spiked cells retained using the Parsortix system and by EpCAM-positive selection using CellSearch® were not significantly different, whereas only the Parsortix system showed strong enrichment of cells with undetectable EpCAM expression. In a pilot clinical study we banked both enriched CTCs as well as plasma from SCLC patient blood samples. Upon retrieval of the banked Parsortix cellular samples we could detect cytokeratin positive CTCs in all 12 SCLC patients tested. Interestingly, processing parallel samples from the same patients by EpCAM enrichment using CellSearch® revealed only 83% (10/12) with cytokeratin positive CTCs indicating the Parsortix system is enriching for EpCAM negative SCLC CTCs. Our combined results indicate the Parsortix system is a valuable tool for combined cfDNA isolation and CTC enrichment that enables CTC analysis to be extended beyond dependence on surface epitopes.

Circulating tumor cell isolation: the assets of filtration methods with polycarbonate track-etched filters

Circulating tumor cells (CTCs) arise from primary or secondary tumors and enter the bloodstream by active or passive intravasation. Given the low number of CTCs, enrichment is necessary for detection. Filtration methods are based on selection of CTCs by size using a filter with 6.5 to 8 µm pores. After coloration, collected CTCs are evaluated according to morphological criteria. Immunophenotyping and fluorescence in situ hybridization techniques may be used. Selected CTCs can also be cultivated in vitro to provide more material. Analysis of genomic mutations is difficult because it requires adapted techniques due to limited DNA materials. Filtration-selected CTCs have shown prognostic value in many studies but multicentric validating trials are mandatory to strengthen this assessment. Other clinical applications are promising such as follow-up, therapy response prediction and diagnosis. Microfluidic emerging systems could optimize filtration-selected CTCs by increasing selection accuracy.