A pilot study to explore circulating tumour cells in pancreatic cancer as a novel biomarker

Tumourigenic non-small-cell lung cancer mesenchymal circulating tumour cells: a clinical case study

BACKGROUND

Over the past decade, numerous reports describe the generation and increasing utility of non-small-cell lung cancer (NSCLC) patient-derived xenografts (PDX) from tissue biopsies. While PDX have proven useful for genetic profiling and preclinical drug testing, the requirement of a tissue biopsy limits the available patient population, particularly those with advanced oligometastatic disease. Conversely, 'liquid biopsies' such as circulating tumour cells (CTCs) are minimally invasive and easier to obtain. Here, we present a clinical case study of a NSCLC patient with advanced metastatic disease, a never smoker whose primary tumour was EGFR and ALK wild-type. We demonstrate for the first time, tumorigenicity of their CTCs to generate a patient CTC-derived eXplant (CDX).

PATIENTS AND METHODS

CTCs were enriched at diagnosis and again 2 months later during disease progression from 10 ml blood from a 48-year-old NSCLC patient and implanted into immunocompromised mice. Resultant tumours were morphologically, immunohistochemically, and genetically compared with the donor patient's diagnostic specimen. Mice were treated with cisplatin and pemetrexed to assess preclinical efficacy of the chemotherapy regimen given to the donor patient.

RESULTS

The NSCLC CDX expressed lung lineage markers TTF1 and CK7 and was unresponsive to cisplatin and pemetrexed. Examination of blood samples matched to that used for CDX generation revealed absence of CTCs using the CellSearch EpCAM-dependent platform, whereas size-based CTC enrichment revealed abundant heterogeneous CTCs of which ∼80% were mesenchymal marker vimentin positive. Molecular analysis of the CDX, mesenchymal and epithelial CTCs revealed a common somatic mutation confirming tumour origin and showed CDX RNA and protein profiles consistent with the predominantly mesenchymal phenotype.

CONCLUSIONS

This study shows that the absence of NSCLC CTCs detected by CellSearch (EpCAM(+)) does not preclude CDX generation, highlighting epithelial to mesenchymal transition and the functional importance of mesenchymal CTCs in dissemination of this disease.

Clinical significance of pancreatic circulating tumor cells using combined negative enrichment and immunostaining-fluorescence in situ hybridization

BACKGROUND

Circulating tumor cells (CTCs) hold great potential in both clinical application and basic research for the managements of cancer. However, it remains to be an enormous challenge to obtain efficient detection of pancreatic CTCs. New detection platforms for the detection of pancreatic CTCs are urgently required.

METHODS

In the present study, we applied a newly-developed platform integrated subtraction enrichment and immunostaining-fluorescence in situ hybridization (SE-iFISH) to analyze clinical significance of pancreatic CTCs. Immunostaining of CK, CD45, DAPI and FISH with the centromere of chromosome 8 (CEP8) were utilized to identify CTCs. Cells with features of CK+/CD45-/DAPI+/CEP8 = 2, CK+/CD45-/DAPI+/CEP8 > 2, CK-/CD45-/DAPI+/CEP8 > 2 were defined as pancreatic CTCs. The Kaplan-Meier method and Cox proportional hazards model were used to analyze the relationship of CTC level and other clinicopathological factors with pancreatic cancer clinical outcomes.

RESULTS

CTC count in pancreatic cancer was higher than healthy individuals (median, 3 vs. 0 per 7.5 ml; P < 0.001). SE-iFISH platform yielded a sensitivity of 88% and specificity of 90% in pancreatic cancer at the cutoff value of 2 cells/7.5 ml. Pancreatic cancer patients with lower CTC count (<3/7.5 ml) had substantially better overall survival (OS) compared with these with higher CTC count (≥3/7.5 ml) (15.2 vs. 10.2 months, P = 0.023). Multivariate analysis indicated that higher CTC count was a strong indicator for worse OS (HR = 4.547, P = 0.016).

CONCLUSION

Our current data showed that CTCs could be detected in pancreatic cancer patients in various stages, whether localized, locally advanced and metastatic. Besides, CTCs have shown the potential implication in predicting prognosis of pancreatic cancer.

The Role of CTCs as Tumor Biomarkers

Detection of Circulating Tumor Cells (CTCs) in peripheral blood can serve as a "liquid biopsy" approach and as a source of valuable tumor markers. CTCs are rare, and thus their detection, enumeration and molecular characterization are very challenging. CTCs have the unique characteristic to be non-invasively isolated from blood and used to follow patients over time, since these cells can provide significant information for better understanding tumour biology and tumour cell dissemination. CTCs molecular characterization offers the unique potential to understand better the biology of metastasis and resistance to established therapies and their analysis presents nowadays a promising field for both advanced and early stage patients. In this chapter we focus on the latest findings concerning the clinical relevance of CTC detection and enumeration, and discuss their potential as tumor biomarkers in various types of solid cancers. We also highlight the importance of performing comparison studies between these different methodologies and external quality control systems for establishing CTCs as tumor biomarkers in the routine clinical setting.

Clinical Significance of Circulating Tumor Microemboli as a Prognostic Marker in Patients with Pancreatic Ductal Adenocarcinoma

BACKGROUND

Characterization of circulating tumor cells (CTCs) has been used to provide prognostic, predictive, and pharmacodynamic information in many different cancers. However, the clinical significance of CTCs and circulating tumor microemboli (CTM) in patients with pancreatic ductal adenocarcinoma (PDAC) has yet to be determined.

METHODS

In this prospective study, CTCs and CTM were enumerated in the peripheral blood of 63 patients with PDAC before treatment using anti-EpCAM (epithelial cell adhesion molecule)–conjugated supported lipid bilayer–coated microfluidic chips. Associations of CTCs and CTM with patients' clinical factors and prognosis were determined.

RESULTS

CTCs were abundant [mean (SD), 70.2 (107.6)] and present in 81% (51 of 63) of patients with PDAC. CTM were present in 81% (51 of 63) of patients with mean (SD) 29.7 (1101.4). CTM was an independent prognostic factor of overall survival (OS) and progression free survival (PFS). Patients were stratified into unfavorable and favorable CTM groups on the basis of CTM more or less than 30 per 2 mL blood, respectively. Patients with baseline unfavorable CTM, compared with patients with favorable CTM, had shorter PFS (2.7 vs 12.1 months; P &lt; 0.0001) and OS (6.4 vs 19.8 months; P &lt; 0.0001). Differences persisted if we stratified patients into early and advanced diseases. The number of CTM before treatment was an independent predictor of PFS and OS after adjustment for clinically significant factors.

CONCLUSIONS

The number of CTM, instead of CTCs, before treatment is an independent predictor of PFS and OS in patients with PDAC.

Overexpression of microRNA-5100 decreases the aggressive phenotype of pancreatic cancer cells by targeting PODXL

Metastasis is the main cause of cancer-associated death, and metastasis of pancreatic cancer remains difficult to treat because of its aggressiveness. MicroRNAs (miRNAs) play crucial roles in the regulation of various human transcripts, and many miRNAs have been reported to correlate with cancer metastasis. We identified an anti-metastatic miRNA, miR-5100, by investigating differences in miRNA profiling between highly metastatic pancreatic cancer cells and their parental cells. Overexpression of miR-5100 inhibited colony formation (P<0.05), cell migration (P<0.0001) and invasion (P<0.0001) of pancreatic cancer cells. In addition, we identified a possible target of miR-5100, podocalyxin-like 1 (PODXL), and demonstrated miR-5100 directly binds to the 3' untranslated region of PODXL and post-transcriptionally regulates its expression in pancreatic cancer cells. Silencing PODXL resulted in diminished cell migration (P<0.0001) and invasion (P<0.05). We also clarified the close relationship between expression of PODXL in human pancreatic cancer specimens and liver metastasis (P=0.0003), and determined that post-operative survival was longer in the low-PODXL expression group than in the high-PODXL expression group (P<0.05). These results indicate that miR-5100 and PODXL have considerable therapeutic potential for anti-metastatic therapy and could be potential indicators for cancer metastases in patients with pancreatic cancer.

Clinical applications of circulating tumor DNA and circulating tumor cells in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent pancreatic cancer type and is characterized by a dismal prognosis due to late diagnosis, local tumor invasion, frequent distant metastases and poor sensitivity to current therapy. In this context, circulating tumor cells and circulating tumor DNA constitute easily accessible blood-borne tumor biomarkers that may prove their clinical interest for screening, early diagnosis and metastatic risk assessment of PDAC. Moreover these markers represent a tool to assess PDAC mutational landscape. In this review, together with key biological findings, we summarize the clinical results obtained using "liquid biopsies" at the different stages of the disease, for early and metastatic diagnosis as well as monitoring during therapy.

Do circulating tumor cells, exosomes, and circulating tumor nucleic acids have clinical utility? A report of the association for molecular pathology

Diagnosing and screening for tumors through noninvasive means represent an important paradigm shift in precision medicine. In contrast to tissue biopsy, detection of circulating tumor cells (CTCs) and circulating tumor nucleic acids provides a minimally invasive method for predictive and prognostic marker detection. This allows early and serial assessment of metastatic disease, including follow-up during remission, characterization of treatment effects, and clonal evolution. Isolation and characterization of CTCs and circulating tumor DNA (ctDNA) are likely to improve cancer diagnosis, treatment, and minimal residual disease monitoring. However, more trials are required to validate the clinical utility of precise molecular markers for a variety of tumor types. This review focuses on the clinical utility of CTCs and ctDNA testing in patients with solid tumors, including somatic and epigenetic alterations that can be detected. A comparison of methods used to isolate and detect CTCs and some of the intricacies of the characterization of the ctDNA are also provided.

[No-touch pancreatectomy and radical antegrade modular pancreatosplenectomy: a systematic review]

AIM

To summarize the data of 'no-touch isolation technique' (NIT) for pancreatoduodenectomy and radical antegrade modular pancreato-splenectomy (RAMPS) for pancreatic malignancies.

MATERIAL AND METHODS

We looked through Pubmed and Cochrane databases for scientific papers published from January 2000 until September 2014.

RESULTS

Eight studies were included. There were 7 retrospective cohort studies and one randomized controlled trial (RCT). Mean operation time and blood loss were 267 min (198-386 min) and 132 ml (331-744 ml) respectively. Mean morbidity rate was 35% (17-58%). There was no 30-day mortality. Mean incidence of R0-resection varied from 50% to 97% with average value 84%. Median survival was reported in 3 studies (17, 18 and 26 months). Five-year actuarial overall survival was reported in 4 studies (31, 36, 40 and 53%).

CONCLUSION

Positive results of NIT and RAMPS might justify further evaluation of the method in pancreatic cancer. Prospective randomized controlled trials needs to be done to demonstrate the oncological value of this novel surgical technique.

Circulating Tumor Cells in Gastrointestinal Cancer: Current Practices and Future Directions

GI cancers are the leading cause of cancer-related death worldwide primarily due to a combination of late presentation and aggressive biology. The lack of adequate biomarkers for screening, diagnosis, staging, and prognosis confounds clinical decision-making and delays potentially effective therapies. Circulating tumor cells (CTCs) are a new biomarker with particular promise in GI cancers, potentially offering clinicians and researchers real-time access to tumor tissue in a reliable, safe, and cost-effective manner. Preliminary studies have investigated the potential clinical utility of CTCs for all GI cancer types with promising results. Furthermore, advances in single cell analytics have been successfully applied to CTCs, allowing for exciting new clinical and research applications. In this chapter, we will review the current state of CTC research in GI cancers as well as the potential future applications that are currently being developed.

KRAS mutations in pancreatic circulating tumor cells: a pilot study

Pancreatic ductal adenocarcinoma (PDAC) is most often diagnosed in a metastatic stage. Circulating tumor cells (CTC) in the blood are hypothesized as the means of systemic dissemination. We aimed to isolate and characterize CTC to evaluate their significance as prognostic markers in PDAC. Blood obtained from healthy donors and patients with PDAC before therapy was filtered with ScreenCell® filtration devices for size-based CTC isolation. Captured cells were analyzed by immunofluorescence for an epithelial to mesenchymal transition (EMT) marker (zinc finger E-box binding homebox 1 (ZEB1)) and an epithelial antigen (cytokeratin (CK)). Molecular analysis of parallel specimens evaluated the KRAS mutation status of the CTC. The survival of each patient after study was recorded. As demonstrated by either cytology or finding of a KRAS mutation, CTC were detected in 18 of 21 patients (86 %) with proven PDAC: 8 out of 10 patients (80 %) with early stage (UICC IIA/IIB) and 10 out of 11 (91 %) with late stage (UICC III/IV) disease. CTC were not found in any of the 10 control patients (p < 0.001). The presence of CTC did not adversely affect median survival: 16 months in CTC-positive (n = 18) vs. 10 months in CTC-negative (n = 3) patients. Neither ZEB1 nor cytological characteristics correlated with overall survival, although ZEB1 was found almost exclusively in CTC of patients with established metastases. Patients with a CTC KRAS mutation (CTC-KRAS (mut)) had a substantially better survival, 19.4 vs. 7.4 months than patients with wild type KRAS (p = 0.015). With ScreenCell filtration, CTC are commonly found in PDAC (86 %). Molecular and genetic characterization, including mutations such as KRAS, may prove useful for prognosis.

Acquisition of Portal Venous Circulating Tumor Cells From Patients With Pancreaticobiliary Cancers by Endoscopic Ultrasound

BACKGROUND & AIMS

Tumor cells circulate in low numbers in peripheral blood; their detection is used predominantly in metastatic disease. We evaluated the feasibility and safety of sampling portal venous blood via endoscopic ultrasound (EUS) to count portal venous circulating tumor cells (CTCs), compared with paired peripheral CTCs, in patients with pancreaticobiliary cancers (PBCs).

METHODS

In a single-center cohort study, we evaluated 18 patients with suspected PBCs. Under EUS guidance, a 19-gauge EUS fine needle was advanced transhepatically into the portal vein and as many as four 7.5-mL aliquots of blood were aspirated. Paired peripheral blood samples were obtained. Epithelial-derived CTCs were sorted magnetically based on expression of epithelial cell adhesion molecules; only those with a proper morphology and found to be CD45 negative and positive for cytokeratins 8, 18, and/or 19 and 4',6-diamidino-2-phenylindole were considered to be CTCs. For 5 samples, CTCs also were isolated by flow cytometry and based on CD45 depletion. ImageStream was used to determine the relative protein levels of P16, SMAD4, and P53. DNA was extracted from CTCs for sequencing of select KRAS codons.

RESULTS

There were no complications from portal vein blood acquisition. We detected CTCs in portal vein samples from all 18 patients (100%) vs peripheral blood samples from only 4 patients (22.2%). Patients with confirmed PBCs had a mean of 118.4 ± 36.8 CTCs/7.5 mL portal vein blood, compared with a mean of 0.8 ± 0.4 CTCs/7.5 mL peripheral blood (P < .01). The 9 patients with nonmetastatic, resectable, or borderline-resectable PBCs had a mean of 83.2 CTCs/7.5 mL portal vein blood (median, 62.0 CTCs/7.5 mL portal vein blood). In a selected patient, portal vein CTCs were found to carry the same mutations as those detected in a metastatic lymph node and expressed similar levels of P16, SMAD4, and P53 proteins.

CONCLUSIONS

It is feasible and safe to collect portal venous blood from patients undergoing EUS. We identified CTCs in all portal vein blood samples from patients with PBCs, but less than 25% of peripheral blood samples. Portal vein CTCs can be used for molecular characterization of PBCs and share features of metastatic tissue. This technique might be used to study the pathogenesis and progression of PBCs, as well as a diagnostic or prognostic tool to stratify risk of cancer recurrence or developing metastases.

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.

Circulating tumor cells (Ctc) and kras mutant circulating free Dna (cfdna) detection in peripheral blood as biomarkers in patients diagnosed with exocrine pancreatic cancer

BACKGROUND

Pancreatic cancer remains one of the most difficult cancers to treat with the poorest prognosis. The key to improving survival rates in this disease is early detection and monitoring of disseminated and residual disease. However, this is hindered due to lack reliable diagnostic and predictive markers which mean that the majority of patients succumb to their condition within a few months.

METHODS

We present a pilot study of the detection circulating free DNA (cfDNA) combined with tumor specific mutation detection by digital PCR as a novel minimally invasive biomarker in pancreatic ductal adenocarcinoma (PDAC). This was compared to the detection of CTC by the CellSearch® system and a novel CTC enrichment strategy based on CD45 positive cell depletion. The aim of the study was to assess tumor specific DNA detection in plasma and CTC detection as prognostic markers in PDAC.

RESULTS

We detected KRAS mutant cfDNA in 26% of patients of all stages and this correlated strongly with Overall Survival (OS), 60 days (95% CI: 19-317) for KRAS mutation positive vs 772 days for KRAS mutation negative (95% CI: 416-1127). Although, the presence of CTC detected by the CellSearch® system did correlate significantly with OS, 88 days (95% CI: 27-206) CTC positive vs 393 days CTC negative (95% CI: 284-501), CTC were detected in only 20% of patients, the majority of which had metastatic disease, whereas KRAS mutant cfDNA was detected in patients with both resectable and advanced disease.

CONCLUSIONS

Tumor specific cfDNA detection and CTC detection are promising markers for the management of patients with PDAC, although there is a need to validate these results in a larger patient cohort and optimize the detection of CTC in PDAC by applying the appropriate markers for their detection.

Current Status of CTCs as Liquid Biopsy in Lung Cancer and Future Directions

Circulating tumor cells (CTCs) have garnered a lot of attention in the past few decades. Isolation of these rare cells from the billions of blood cells has been a challenge until recent times. With the advent of new sensitive technologies that permit live cell isolation and downstream genomic analysis, the existing paradigm of CTC research has evolved to explore clinical utility of these cells. CTCs have been identified as prognostic and pharmacodynamic biomarkers in many solid tumors, including lung cancer. As a means of liquid biopsy, CTCs could play a major role in the development of personalized medicine and targeted therapies. This review discusses the state of various isolation strategies, cell separation techniques and key studies that illustrate the application of liquid biopsy to lung cancer.

Improving pancreatic cancer diagnosis using circulating tumor cells: prospects for staging and single-cell analysis

Pancreatic cancer (PC) is the fourth most common cause of cancer-related death in the USA, primarily due to late presentation coupled with an aggressive biology. The lack of adequate biomarkers for diagnosis and staging confound clinical decision-making and delay potentially effective therapies. Circulating tumor cells (CTCs) are a promising new biomarker in PC. Preliminary studies have demonstrated their potential clinical utility, and newer CTC isolation platforms have the potential to provide clinicians access to tumor tissue in a reliable, real-time manner. Such a 'liquid biopsy' has been demonstrated in several cancers, and small studies have demonstrated its potential applications in PC. This article reviews the available literature on CTCs as a biomarker in PC and presents the latest innovations in CTC research as well as their potential applications in PC.

Circulating Tumor Cell Analyses in Patients With Esophageal Squamous Cell Carcinoma Using Epithelial Marker-Dependent and -Independent Approaches

In several epithelial malignancies, detection of circulating tumor cells (CTCs) in the peripheral blood has diagnostic, prognostic, and therapeutic implications. However, the clinical relevance of CTCs in esophageal squamous cell carcinoma (ESCC) has not yet been ascertained. The study was conducted with the aim of determining the clinical significance of CTCs in patients with ESCC by using 2 CTC detection systems, one epithelial marker-dependent and the other epithelial marker-independent. Paired peripheral blood samples were prospectively obtained from 61 ESCC patients before treatment and were analyzed for CTCs isolated by the CellSearch system (CS) and the method of isolation by size of epithelial tumor (ISET). Blood samples from 22 healthy volunteers were used as controls. Out of 61 study subjects, CTCs were detected in 20 patients (32.8%) by the ISET method and in only 1 patient (1.6%) by the CS method. Circulating tumor microemboli (CTM) were observed in 3 of 61 (4.9%) patients using ISET, but were undetectable in any of the patient by CS method. No CTCs/CTM were detected by either method in control groups. By ISET method, the presence of CTCs appeared to correlate with the stage of ESCC and with the baseline median platelet levels. No correlation with any other relevant clinicopathological variables was observed. Our results clearly indicate the ability of both CS and ISET methods to detect CTCs in peripheral blood samples from ESCC patients. However, the CellSearch system appears to have a poorer sensitivity as compared with the ISET method. Further studies are essential for assessing the role of such technologies in ESCC.

Detection of KRAS mutations in circulating tumor cells from patients with metastatic colorectal cancer

BACKGROUND

Quantification of Circulating Tumor Cells (CTCs) as a prognostic marker in metastatic colorectal cancer (mCRC) has already been validated and approved for routine use. However, more than quantification, qualification or characterization of CTCs is gaining importance, since the genetic characterization of CTCs may reflect, in a real time fashion, genetic profile of the disease.

OBJECTIVE

To characterize KRAS mutations (codon 12 and 13) in CTCs from patients with mCRC and to compare with matched primary tumor. Additionally, correlate these mutations with clinical and pathological features of patients.

METHODS

Blood samples were collected from 26 patients with mCRC from the AC Camargo Cancer Center (São Paulo-Brazil). CTCs were isolated by ISET technology (Isolation by Size of Epithelial Tumors; Rarecells Diagnostics, France) and mutations analyzes were performed by pyrosequencing (QIAGEN).

RESULTS

KRAS mutation was detected in 7 of the 21 cases (33%) of samples from CTCs. In matched primary tumors, 9 of the 24 cases (37.5%) were found KRAS mutated. We observed that 5 of the 9 samples with KRAS mutation in their primary tumor had also KRAS mutation in CTCs, meaning a concordance of 71% of matched cases (P = 0.017). KRAS mutation neither on primary tumor nor in CTCs was associated with clinical-pathological parameters analyzed.

CONCLUSION

Faced with a polyclonal disease like colorectal cancer, which is often treated with alternating and successive lines of chemotherapy, real time genetic characterization of CTCs, in a fast and feasible fashion, can provide important information to clinical management of metastatic patients. Although our cohort was limited, it was possible to show a high grade of concordance between primary tumor and CTCs, which suggests that CTCs can be used as surrogate of primary tumors in clinical practice, when the knowledge of mutation profile is necessary and the primary tumor is not available.

Cediranib or placebo in combination with cisplatin and gemcitabine chemotherapy for patients with advanced biliary tract cancer (ABC-03): a randomised phase 2 trial

BACKGROUND

Cisplatin and gemcitabine is the standard first-line chemotherapy regimen for patients with advanced biliary tract cancer; expression of VEGF and its receptors is associated with adverse outcomes. We aimed to assess the effect of the addition of cediranib (an oral inhibitor of VEGF receptor 1, 2, and 3) to cisplatin and gemcitabine on progression-free survival.

METHODS

In this multicentre, placebo-controlled, randomised phase 2 study, we recruited patients aged 18 years or older with histologically confirmed or cytologically confirmed advanced biliary tract cancer from hepatobiliary oncology referral centres in the UK. Patients were eligible if they had an ECOG performance status of 0-1 and an estimated life expectancy of longer than 3 months. Patients were given first-line cisplatin and gemcitabine chemotherapy (25 mg/m(2) cisplatin and 1000 mg/m(2) gemcitabine [on days 1 and 8 every 21 days, for up to eight cycles]) with either 20 mg oral cediranib or placebo once a day until disease progression. We randomly assigned patients (1:1) with a minimisation algorithm, incorporating the stratification factors: extent of disease, primary disease site, previous treatment, ECOG performance status, and centre. The primary endpoint was progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00939848, and was closed on Sept 30, 2014; results of the final analysis for the primary endpoint are presented.

FINDINGS

Between April 5, 2011, and Sept 28, 2012, we enrolled 124 patients (62 in each group). With a median follow-up of 12·2 months (IQR 7·3-18·5), median progression-free survival was 8·0 months (95% CI 6·5-9·3) in the cediranib group and 7·4 months (5·7-8·5) in the placebo group (HR 0·93, 80% CI 0·74-1·19, 95% CI 0·65-1·35; p=0·72). Patients who received cediranib had more grade 3-4 toxic effects than did patients who received placebo: hypertension (23 [37%] vs 13 [21%]; p=0·05), diarrhoea (eight [13%] vs two [3%]; p=0·05); platelet count decreased (ten [16%] vs four [6%]; p=0·09), white blood cell decreased (15 [24%] vs seven [11%]; p=0·06) and fatigue (16 [24%] vs seven [11%]; p=0·04).

INTERPRETATION

Cediranib did not improve the progression-free survival of patients with advanced biliary tract cancer in combination with cisplatin and gemcitabine, which remains the standard of care. Although patients in the cediranib group had more adverse events, we recorded no unexpected toxic effects. The role of VEGF inhibition in addition to chemotherapy for patients with advanced biliary tract cancer remains investigational.

FUNDING

Cancer Research UK and AstraZeneca Pharmaceuticals.

The detection of EpCAM(+) and EpCAM(-) circulating tumor cells

EpCAM expressing circulating tumor cells, detected by CellSearch, are predictive of short survival in several cancers and may serve as a liquid biopsy to guide therapy. Here we investigate the presence of EpCAM(+) CTC detected by CellSearch and EpCAM(-) CTC discarded by CellSearch, after EpCAM based enrichment. EpCAM(-) CTC were identified by filtration and fluorescent labelling. This approach was validated using different cell lines spiked into blood and evaluated on blood samples of 27 metastatic lung cancer patients. The majority of spiked EpCAM(+) cells could be detected with CellSearch, whereas most spiked cells with EpCAM(low) or EpCAM(-) expression were detected using filtration. Five or more CTC were detected in 15% of the patient samples, this increased to 41% when adding the CTC detected in the discarded blood. The number of patients with CTC and the number of CTC detected were doubled by the presence of EpCAM(-) CTC. In this pilot study, the presence of EpCAM(+) CTC was associated with poor outcome, whereas the EpCAM(-) CTC were not. This observation will need to be confirmed in larger studies and molecular characterization needs to be conducted to elucidate differences between EpCAM(-) and EpCAM(+) CTC.

A meta-analysis of extended versus standard lymphadenectomy in patients undergoing pancreatoduodenectomy for pancreatic adenocarcinoma

BACKGROUND

Lymph node involvement in pancreatic adenocarcinoma is a key prognostic factor. Therefore, extending the number of lymph node stations excised in pancreatoduodenectomy may be beneficial to patients with pancreatic adenocarcinoma. This systematic review and meta-analysis examines the outcomes of extended versus standard lymphadenectomy in the published literature.

METHODS

A meta-analysis of randomized controlled trials (RCTs) comparing extended with standard lymphadenectomy in patients undergoing pancreatoduodenectomy for pancreatic adenocarcinoma was performed. Perioperative outcomes were assessed as pooled odds ratios (ORs) and weighted mean differences. Overall survival was analysed for patients with positive and negative lymph nodes. Results were reported according to the PRISMA statement.

RESULTS

Five RCTs were included, accounting for 724 patients. Extended lymphadenectomy was associated with greater operative time [mean difference: 63 min, 95% confidence interval (CI) 29-96; P < 0.001], increased need for blood transfusions (mean difference: 0.20, 95% CI 0.01-0.30; P = 0.030) and greater postoperative morbidity (OR 1.5, 95% CI 1.25-2.00; P = 0.030), as well as with prolonged diarrhoea after circumferential autonomic nerve dissection around major vessels (OR 12.2, 95% CI 5.3-28.5; P < 0.001). Median survival was similar across the groups in the whole cohort, as well as in subgroups of patients with, respectively, positive and negative lymph nodes.

CONCLUSIONS

Extended lymphadenectomy has a harmful impact on patients undergoing oncological pancreatoduodenectomy compared with standard lymphadenectomy.

Circulating Epithelial Cells in Patients with Pancreatic Lesions: Clinical and Pathologic Findings

BACKGROUND

Circulating epithelial cell (CEC) isolation has provided diagnostic and prognostic information for a variety of cancers, previously supporting their identity as circulating tumor cells in the literature. However, we report CEC findings in patients with benign, premalignant, and malignant pancreatic lesions using a size-selective filtration device.

STUDY DESIGN

Peripheral blood samples were drawn from patients found to have pancreatic lesions on preoperative imaging at a surgical clinic. Blood was filtered using ScreenCell devices, which were evaluated microscopically by a pancreatic cytopathologist. Pathologic data and clinical outcomes of these patients were obtained from medical records during a 1-year follow-up period.

RESULTS

Nine healthy volunteers formed the control group and were found to be negative for CECs. There were 179 patients with pancreatic lesions that formed the study cohort. Circulating epithelial cells were morphologically similar in patients with a variety of pancreatic lesions. Specifically, CECs were identified in 51 of 105 pancreatic ductal adenocarcinomas (49%), 7 of 11 neuroendocrine tumors (64%), 13 of 21 intraductal papillary mucinous neoplasms (62%), and 6 of 13 patients with chronic pancreatitis. Rates of CEC identification were similar in patients with benign, premalignant, and malignant lesions (p = 0.41). In addition, CEC findings in pancreatic ductal adenocarcinoma patients were not associated with poor prognosis.

CONCLUSIONS

Although CECs were not identified in healthy volunteers, they were identified in patients with benign, premalignant, and malignant pancreatic lesions. The presence of CECs in patients presenting with pancreatic lesions is neither diagnostic of malignancy nor prognostic for patients with pancreatic ductal adenocarcinoma.

Analytical Validation and Capabilities of the Epic CTC Platform: Enrichment-Free Circulating Tumour Cell Detection and Characterization

The Epic Platform was developed for the unbiased detection and molecular characterization of circulating tumour cells (CTCs). Here, we report assay performance data, including accuracy, linearity, specificity and intra/inter-assay precision of CTC enumeration in healthy donor (HD) blood samples spiked with varying concentrations of cancer cell line controls (CLCs). Additionally, we demonstrate clinical feasibility for CTC detection in a small cohort of metastatic castrate-resistant prostate cancer (mCRPC) patients. The Epic Platform demonstrated accuracy, linearity and sensitivity for the enumeration of all CLC concentrations tested. Furthermore, we established the precision between multiple operators and slide staining batches and assay specificity showing zero CTCs detected in 18 healthy donor samples. In a clinical feasibility study, at least one traditional CTC/mL (CK+, CD45-, and intact nuclei) was detected in 89 % of 44 mCRPC samples, whereas 100 % of samples had CTCs enumerated if additional CTC subpopulations (CK-/CD45- and CK+ apoptotic CTCs) were included in the analysis. In addition to presenting Epic Platform's performance with respect to CTC enumeration, we provide examples of its integrated downstream capabilities, including protein biomarker expression and downstream genomic analyses at single cell resolution.

Circulating tumor cells found in patients with localized and advanced pancreatic cancer

OBJECTIVES

Isolation of circulating tumor cells (CTCs) holds the promise of diagnosing and molecular profiling cancers from a blood sample. Here, we test a simple new low-cost filtration device for CTC isolation in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Peripheral blood samples drawn from healthy donors and PDAC patients were filtered using ScreenCell devices, designed to capture CTCs for cytologic and molecular analysis. Giemsa-stained specimens were evaluated by a pancreatic cytopathologist blinded to the histological diagnosis. Circulating tumor cell DNA was subjected to KRAS mutational analysis.

RESULTS

Spiking experiments demonstrated a CTC capture efficiency as low as 2 cells/mL of blood. Circulating tumor cells were identified by either malignant cytology or presence of KRAS mutation in 73% of 11 patients (P = 0.001). Circulating tumor cells were identified in 3 of 4 patients with early (≤American Joint Committee on Cancer stage IIB) and in 5 of 7 patients with advanced (≥ American Joint Committee on Cancer stage III) PDAC. No CTCs were detected in blood from 9 health donors.

CONCLUSIONS

Circulating tumor cells can be found in most patients with PDAC of any stage, whether localized, locally advanced, or metastatic. The ability to capture, cytologically identify, and genetically analyze CTCs suggests a possible tool for the diagnosis and characterization of genetic alterations of PDAC.

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

Thymidylate synthase (TYMS) is an important enzyme for 5‐fluorouracil (5‐FU) metabolism in metastatic colorectal cancer (mCRC) patients. The search for this enzyme in circulating tumor cells (CTCs) can be a powerful tool to follow‐up cancer patients. mCRC patients were enrolled before the beginning of 5‐FU‐based chemotherapy. The blood was filtered on Isolation by Size of Epithelial Tumor Cells (ISET), and the analysis of TYMS expression in CTCs was made by immunocytochemistry. Additionally, we verified TYMS staining in primary tumors and metastases from the same patients. There were included 54 mCRC patients and 47 of them received 5‐FU‐based chemotherapy. The median CTCs number was 2 per mL. We were not able to analyze immunocytochemistry in 13 samples (9 patients with absence of CTCs and 4 samples due to technical reasons). Therefore, TYMS expression on CTCs was analyzed in 34 samples and was found positive in 9 (26.5%). Six of these patients had tumor progression after treatment with 5‐FU. We found an association between CTC TYMS staining and disease progression (DP), although without statistical significance (P = 0.07). TYMS staining in primary tumors and metastases tissues did not have any correlation with disease progression (P = 0.67 and P = 0.42 respectively). Patients who had CTC count above the median (2 CTCs/mL) showed more TYMS expression (P = 0.02) correlating with worse prognosis. Our results searching for TYMS staining in CTCs, primary tumors and metastases suggest that the analysis of TYMS can be useful tool as a 5‐FU resistance predictor biomarker if analyzed in CTCs from mCRC patients.

What's new?

Currently, the common treatment strategy for metastatic colorectal cancer patients is 5‐Fluorouracil‐based chemotherapy, which shows high efficacy in a subset of patients. Even those patients, however, can experience disease progression due to 5‐FU resistance. There are indications that the DNA replication and repair enzyme thymidylate synthase (TYMS) may be involved. Here, the authors set to measure circulating tumor cells levels and search for TYMS staining to correlate these findings with clinical outcome. The results suggest that circulating tumor cells represent a powerful tool to follow up 5‐FU resistance in metastatic colorectal cancer patients in real time, by TYMS expression analysis.

Biomarkers for early diagnosis of pancreatic cancer

Pancreatic ductal adenocarcinoma is an aggressive malignancy with a 5-year survival rate of approximately 5%. The lack of established strategies for early detection contributes to this poor prognosis. Although several novel candidate biomarkers have been proposed for earlier diagnosis, none have been adopted into routine clinical use. In this review, the authors examine the challenges associated with finding new pancreatic cancer diagnostic biomarkers and explore why translation of biomarker research for patient benefit has thus far failed. The authors also review recent progress and highlight advances in the understanding of the biology of pancreatic cancer that may lead to improvements in biomarker detection and implementation.

The biological and clinical importance of epithelial-mesenchymal transition in circulating tumor cells

Movement of tumor cells from a primary tumor to a nonadjacent or distant site is a contiguous and complex process. Among the multiple natural cellular programs that promote initiation and progression of tumor metastasis, epithelial-mesenchymal transition (EMT) may play a key role in the ultimate generation of a metastatic foci. Acquisition of the EMT phenotype by tumor cells not only increases their migration and invasion potentials, thereby facilitating their ability to infiltrate blood vessels and to produce circulating tumor cells (CTCs), but also promotes survival of CTCs in the bloodstream and their ability to extravasate out of the circulatory system and invade proximal tissues. In organs distal to the primary tumor, the phenotypic switching mechanism of mesenchymal-epithelial transition (MET) enables CTCs to grow and colonize, enhancing the likelihood of establishing metastasis. In addition, CTCs that have undergone EMT attain increased resistance to chemotherapy and targeted therapy. CTCs with the EMT phenotype have become recognized as an active source of metastases, and targeting EMT/MET processes during the individual steps of tumor metastasis represents a promising new approach for alleviating cancer metastasis and recurrence. In this article, we focus on the biological and clinical importance of EMT and/or MET in CTCs during the individual steps of tumor metastasis, summarizing the recent findings of the regulatory roles played by EMT and/or MET in the generation, survival, and recolonization of CTCs and discussing the EMT-targeting strategies developed for tumor diagnosis as well as their potential for management of metastatic malignant diseases.

Circulating Tumor Cells: Who is the Killer?

This article is a critical note on the subject of Circulating Tumor Cells (CTC). It takes into account the tumor identity of Circulating Tumor Cells as cancer seeds in transit from primary to secondary soils, rather than as a “biomarker”, and considers the help this field could bring to cancer patients. It is not meant to duplicate information already available in a large number of reviews, but to stimulate considerations, further studies and development helping the clinical use of tumor cells isolated from blood as a modern personalized, non-invasive, predictive test to improve cancer patients’ life. The analysis of CTC challenges, methodological bias and critical issues points out to the need of referring to tumor cells extracted from blood without any bias and identified by cytopathological diagnosis as Circulating Cancer Cells (CCC). Finally, this article highlights recent developments and identifies burning questions which should be addressed to improve our understanding of the domain of CCC and their potential to change the clinical practice.

A radial flow microfluidic device for ultra-high-throughput affinity-based isolation of circulating tumor cells

Circulating tumor cells (CTCs) are believed to play an important role in metastasis, a process responsible for the majority of cancer-related deaths. But their rarity in the bloodstream makes microfluidic isolation complex and time-consuming. Additionally the low processing speeds can be a hindrance to obtaining higher yields of CTCs, limiting their potential use as biomarkers for early diagnosis. Here, a high throughput microfluidic technology, the OncoBean Chip, is reported. It employs radial flow that introduces a varying shear profile across the device, enabling efficient cell capture by affinity at high flow rates. The recovery from whole blood is validated with cancer cell lines H1650 and MCF7, achieving a mean efficiency >80% at a throughput of 10 mL h(-1) in contrast to a flow rate of 1 mL h(-1) standardly reported with other microfluidic devices. Cells are recovered with a viability rate of 93% at these high speeds, increasing the ability to use captured CTCs for downstream analysis. Broad clinical application is demonstrated using comparable flow rates from blood specimens obtained from breast, pancreatic, and lung cancer patients. Comparable CTC numbers are recovered in all the samples at the two flow rates, demonstrating the ability of the technology to perform at high throughputs.

Circulating tumor cells in pancreatic cancer patients: Enrichment and cultivation

AIM: To investigate the feasibility of separation and cultivation of circulating tumor cells (CTCs) in pancreatic cancer (PaC) using a filtration device.

METHODS: In total, 24 PaC patients who were candidates for surgical treatment were enrolled into the study. Peripheral blood samples were collected before an indicated surgery. For each patient, approximately 8 mL of venous blood was drawn from the antecubital veins. A new size-based separation MetaCell^® technology was used for enrichment and cultivation of CTCs in vitro. (Separated CTCs were cultured on a membrane in FBS enriched RPMI media and observed by inverted microscope. The cultured cells were analyzed by means of histochemistry and immunohistochemistry using the specific antibodies to identify the cell origin.

RESULTS: CTCs were detected in 16 patients (66.7%) of the 24 evaluable patients. The CTC positivity did not reflect the disease stage, tumor size, or lymph node involvement. The same percentage of CTC positivity was observed in the metastatic and non-metastatic patients (66.7% vs 66.7%). We report a successful isolation of CTCs in PaC patients capturing proliferating cells. The cells were captured by a capillary action driven size-based filtration approach that enabled cells cultures from the viable CTCs to be unaffected by any antibodies or lysing solutions. The captured cancer cells displayed plasticity which enabled some cells to invade the separating membrane. Further, the cancer cells in the “bottom fraction”, may represent a more invasive CTC-fraction. The CTCs were cultured in vitro for further downstream applications.

CONCLUSION: The presented size-based filtration method enables culture of CTCs in vitro for possible downstream applications.

Isolation, detection, and immunomorphological characterization of circulating tumor cells (CTCs) from patients with different types of sarcoma using isolation by size of tumor cells: a window on sarcoma-cell invasion

Background

Sarcomas are rare and heterogeneous neoplasms with poor prognosis that are thought to spread to distant organs mainly by hematogenous dissemination. However, circulating tumor cells (CTCs) have never been visualized in sarcomas.

Objectives

To investigate the feasibility of using isolation by size of tumor cells (ISET) for isolation, identification, and characterization of CTCs derived from patients with high-grade and metastatic sarcomas.

Patients and methods

We studied eleven patients with metastatic/recurrent or locally advanced soft-tissue sarcomas (STSs), six of whom had synovial sarcomas. Blood samples (8 mL) were collected from patients with advanced STS and treated by ISET, a marker- independent approach that isolates intact CTCs from blood, based on their larger size compared with leukocytes. CTCs were identified by cytomorphology and characterized by dual-color immunocytochemistry using antivimentin or anti-Pan CK, and anti-CD45.

Results

All patients with STS included in this study showed CTCs, with numbers ranging from two to 48 per 8 mL of blood.

Conclusion

This study shows the feasibility of isolating, identifying, and characterizing CTCs from patients with different types of sarcomas and the presence of circulating sarcoma cells in all the tested patients. Our results set the basis for further studies aimed at exploring the presence, number, and immunomolecular characteristics of CTCs in different types of sarcoma, and bring more light to the mechanisms of tumor invasion for these tumors.

Circulating biomarkers in hepatocellular carcinoma

PURPOSE

Our aims are to determine levels of circulating cellular and protein biomarkers in hepatocellular carcinoma (HCC) patients and to analyse any relationships with clinical parameters.

METHODS

Fifty-four consenting patients were recruited. Circulating tumour cells (CTCs) were enumerated (by CellSearch) and characterised via filtration [by isolation by size of epithelial tumour cells (ISET)] with downstream immunohistochemistry (IHC). Glypican-3 (GPC3) expression in tumour biopsies and CTCs (by IHC) was compared, and levels of circulating caspase-cleaved and full-length cytokeratin 18 (CK18, measured using M30 and M65 ELISAs) were examined as a putative prognostic factor and marker of tumour burden.

RESULTS

CTCs were identified in 14 out of 50 (28%) patients by CellSearch and in 19 out of 19 (100%) patients by ISET. The presence of GPC3-positive CTCs by ISET was 100% concordant with the presence of GPC3-positive cells in the original tumour (n = 5). No statistically significant correlations were observed between CTC number and clinical characteristics, although trends were noted between CTC subtypes, Child-Pugh score and tumour node metastasis stage. Serum M30 and M65 levels (as continuous variables) significantly correlated with overall survival (OS) in a univariate analysis (p = 0.003 and p < 0.001, respectively); M65 levels remained statistically significant in a multivariate analysis (p = 0.029).

CONCLUSIONS

This is the first study to detect GPC3-positive CTCs in HCC, important for drug development with this target. The significant association of circulating CK18 with OS in HCC further exemplifies the utility of circulating biomarkers in cancer.

Patterns of circulating tumor cells identified by CEP8, CK and CD45 in pancreatic cancer

To improve the identification for CTCs with weak or negative CK and diploid CTCs in pancreatic cancer, we combined immune-staining of CK, CD45, DAPI and fluorescence in situ hybridization with the centromere of chromosome 8 (CEP8) probe method. CTCs in 3.75 mL of blood were depleted for CD45 positive cells with anti-CD45 antibodies and identified by combining CK, CD45, DAPI and CEP8 in 61 cases including 22 pancreatic cancers, 3 borderline pancreatic solid pseudopapillary tumors, 6 pancreatic benign tumors, and 30 healthy individuals. We found that enriched cells could be classified into 5 patterns: CK+CD45-DAPI+CEP8=2 (2 hybridization signals), CK+CD45-DAPI+CEP8>2 (>2 hybridization signals), CK-CD45-DAPI+CEP8>2, CK-CD45-DAPI+CEP8=2, and CK+/-CD45+DAPI+CEP8=2 or >2. Among 22 pancreatic cancers, CK+CD45-DAPI+CEP8=2 and CK+CD45-DAPI+CEP8>2 patterns were identified in two cases, and CK-CD45- DAPI+CEP8>2 pattern was identified in 16 cases. CK-CD45-DAPI+CEP8=2 and CK+/-CD45+DAPI+CEP8=2 or >2 patterns were detected in pancreatic cancers, other pancreatic diseases and healthy individuals. Among the five patterns, CK+CD45-DAPI+CEP8=2, CK+CD45-DAPI+CEP8>2 and CK-CD45-DAPI+CEP8>2 were considered as CTCs, while CK-CD45-DAPI+CEP8=2 and CK+/-CD45+DAPI+CEP8=2 or >2 were considered as indeterminate cells. When the cutoff value was set as 2 cells/3.75 mL based on ROC curve, the sensitivity and specificity in the diagnosis of pancreatic cancer was 68.18 and 94.87%, respectively. Dynamically monitoring CTCs changes prior to and after surgery in pancreatic patients revealed that CTCs count decreased in 3 days after surgery, but increased in 10 days after surgery in most patients. During our one and a half year follow-up, CTCs positive patients showed metastasis and worse survival rate.

Pancreatic biomarkers: Could they be the answer?

Pancreatic ductal adenocarcinoma (PDA) is known for its poor prognosis. Most of the patients are diagnosed with advanced stages, when no curative treatment is available. Currently, despite extensive clinical research on PDA, the median overall survival remains short. Diagnosis delay and primary chemo-resistance due to its intrinsic biological nature may explain the challenges to improve our results. Our knowledge about the molecular biology of PDA has exponentially increased during the last decades and its use for the development of biomarkers could help to reach better results in the clinical setting. These biomarkers could be the clue for the improvement in PDA clinical research by earlier detection strategies with diagnostic biomarkers, and by an individualization of treatment approach with prognostic and predictive biomarkers. This review summarizes the current knowledge about the molecular biology of PDA and the status of the most important prognostic and predictive biomarkers.

Optimisation of an immunohistochemistry method for the determination of androgen receptor expression levels in circulating tumour cells

BACKGROUND

AZD3514 inhibits and down regulates the androgen receptor (AR) and has undergone clinical trials in prostate cancer. To provide proof-of-mechanism (POM) in patients, an immunohistochemistry (IHC) method for determination of AR in circulating tumour cells (CTC) was developed and validated.

METHODS

After an assessment of specificity validation focused on intra- and inter-operator reproducibility utilising a novel modification of incurred sample reanalysis (ISR). β-Content γ-confidence tolerance intervals (BCTI) and Cohen's Kappa (κ) were employed in statistical analysis of results.

RESULTS

In a first set of IHC reproducibility experiments, almost perfect agreement was recorded (κ=0.94) when two different operators scored CTC as overall positive or negative for AR. However, BCTI analysis identified a specific bias in scoring staining intensity, where one operator favoured moderate over strong assignments, whereas the reverse was the case with the second operator. After a period of additional training involving deployment of a panel of standardised images, a second set of validation experiments were conducted. These showed correction of the inter-operator bias by BCTI with κ for scoring intensity increasing from 0.59 to 0.81, indicative of almost perfect agreement.

CONCLUSIONS

By application of BCTI to the validation of IHC, operator bias and therefore poor reproducibility can be identified, characterised and corrected to achieve a level of error normally associated with a quantitative biomarker assay, such as an ELISA. The methodological approach described herein can be applied to any generic IHC technique.

Circulating tumour cells: the evolving concept and the inadequacy of their enrichment by EpCAM-based methodology for basic and clinical cancer research

Increasing evidence suggests that circulating tumour cells (CTCs) are responsible for metastatic relapse and this has fuelled interest in their detection and quantification. Although numerous methods have been developed for the enrichment and detection of CTCs, none has yet reached the 'gold' standard. Since epithelial cell adhesion molecule (EpCAM)-based enrichment of CTCs offers several advantages, it is one of the most commonly used and has been adapted for high-throughput technology. However, emerging evidence suggests that CTCs are highly heterogeneous: they consist of epithelial tumour cells, epithelial-to-mesenchymal transition (EMT) cells, hybrid (epithelial/EMT(+)) tumour cells, irreversible EMT(+) tumour cells, and circulating tumour stem cells (CTSCs). The EpCAM-based approach does not detect CTCs expressing low levels of EpCAM and non-epithelial phenotypes such as CTSCs and those that have undergone EMT and no longer express EpCAM. Thus, the approach may lead to underestimation of the significance of CTCs, in general, and CTSCs and EMT(+) tumour cells, in particular, in cancer dissemination. Here, we provide a critical review of research literature on the evolving concept of CTCs and the inadequacy of their enrichment by EpCAM-based technology for basic and clinical cancer research. The review also outlines future perspectives in the field.

Molecular biomarkers of cancer stem/progenitor cells associated with progression, metastases, and treatment resistance of aggressive cancers

The validation of novel diagnostic, prognostic, and predictive biomarkers and therapeutic targets in tumor cells is of critical importance for optimizing the choice and efficacy of personalized therapies. Importantly, recent advances have led to the identification of gene-expression signatures in cancer cells, including cancer stem/progenitor cells, in the primary tumors, exosomes, circulating tumor cells (CTC), and disseminated cancer cells at distant metastatic sites. The gene-expression signatures may help to improve the accuracy of diagnosis and predict the therapeutic responses and overall survival of patients with cancer. Potential biomarkers in cancer cells include stem cell-like markers [CD133, aldehyde dehydrogenase (ALDH), CD44, and CD24], growth factors, and their cognate receptors [epidermal growth factor receptor (EGFR), EGFRvIII, and HER2], molecules associated with epithelial-mesenchymal transition (EMT; vimentin, N-cadherin, snail, twist, and Zeb1), regulators of altered metabolism (phosphatidylinositol-3' kinase/Akt/mTOR), and drug resistance (multidrug transporters and macrophage inhibitory cytokine-1). Moreover, different pluripotency-associated transcription factors (Oct3/4, Nanog, Sox2, and Myc) and microRNAs that are involved in the epigenetic reprogramming and acquisition of stem cell-like properties by cancer cells during cancer progression may also be exploited as molecular biomarkers to predict the risk of metastases, systemic treatment resistance, and disease relapse of patients with cancer.

Capture, release and culture of circulating tumor cells from pancreatic cancer patients using an enhanced mixing chip

Circulating tumor cells (CTCs) from peripheral blood hold important information for cancer diagnosis and disease monitoring. Analysis of this "liquid biopsy" holds the promise to usher in a new era of personalized therapeutic treatments and real-time monitoring for cancer patients. But the extreme rarity of CTCs in blood makes their isolation and characterization technologically challenging. This paper reports the development of a geometrically enhanced mixing (GEM) chip for high-efficiency and high-purity tumor cell capture. We also successfully demonstrated the release and culture of the captured tumor cells, as well as the isolation of CTCs from cancer patients. The high-performance microchip is based on geometrically optimized micromixer structures, which enhance the transverse flow and flow folding, maximizing the interaction between CTCs and antibody-coated surfaces. With the optimized channel geometry and flow rate, the capture efficiency reached >90% with a purity of >84% when capturing spiked tumor cells in buffer. The system was further validated by isolating a wide range of spiked tumor cells (50-50,000) in 1 mL of lysed blood and whole blood. With the combination of trypsinization and high flow rate washing, captured tumor cells were efficiently released. The released cells were viable and able to proliferate, and showed no difference compared with intact cells that were not subjected to the capture and release process. Furthermore, we applied the device for detecting CTCs from metastatic pancreatic cancer patients' blood; and CTCs were found from 17 out of 18 samples (>94%). We also tested the potential utility of the device in monitoring the response to anti-cancer drug treatment in pancreatic cancer patients, and the CTC numbers correlated with the clinical computed tomograms (CT scans) of tumors. The presented technology shows great promise for accurate CTC enumeration, biological studies of CTCs and cancer metastasis, as well as for cancer diagnosis and treatment monitoring.

Detection of circulating tumor cells

The increasing number of treatment options for patients with metastatic carcinomas has created an accompanying need for methods to determine if the tumor will be responsive to the intended therapy and to monitor its effectiveness. Ideally, these methods would be noninvasive and provide quantitative real-time analysis of tumor activity in a variety of carcinomas. Assessment of circulating tumor cells shed into the blood during metastasis may satisfy this need. Here we review the CellSearch technology used for the detection of circulating tumor cells and discuss potential future directions for improvements.

Binding and isolation of tumor cells in biological media with perfluorocarbon microbubbles

With the emerging interest in personalized medicine, there is strong demand for new technologies for clinical sample interrogation. Exfoliated tumor cells in variety of pathological samples (e.g., blood, bone marrow, urine) could provide invaluable information for diagnosis and prognosis of cancers. Here we describe a detailed method for capture and isolation of tumor cells in medium, blood, or large issue buffy coat using EpCAM-targeted buoyant microbubbles (MBs). Perflorohexane gas lipid shell MBs were prepared with emulsification method and conjugated with antibody as described by us before [25]. The binding of EpCAM-targeted MBs to A549 (human lung carcinoma) and 4T1 (mouse breast carcinoma) cells spiked into BSA/PBS or blood was more than 90%, which was comparable with commercial anti-EpCAM immunomagnetic beads (DynaBeads). Anti-EpCAM MBs efficiently (75-82%) isolated BxPC3 pancreatic tumor cells spiked into medium, blood or a buffy coat, within 15-30 min of incubation. We discuss MB parameters and experimental conditions critical to achieve efficient cells binding and isolation. In conclusion, MB-assisted cell isolation is a promising method for rapid enrichment of cells and biomarkers from biological samples.

Cytokeratin-based CTC counting unrelated to clinical follow up

BACKGROUND

Circulating tumor cells (CTCs) have been reported to be a relevant prognostic biomarker in metastatic patients. However, their clinical use and impact is still under debate. We have thus comparatively and kinetically assessed two CTC detection methods according to the patient's clinical follow up.

METHODS

CTC counting and characterization were repeatedly performed during follow up in a patient with metastatic undifferentiated non-small cell lung cancer by using cytokeratin (CK)-dependent immunomagnetic separation (Miltenyi) and CK-independent, size-based isolation [isolation by size of tumor cells (ISET)] (Rarecells).

RESULTS

Comparison between the two methods showed a parallel increase of CTC detected by ISET and worsening of the clinical status, while CK-dependent CTC numbers were decreasing, misleadingly suggesting a response to treatment. ISET results were in agreement with the clinical follow up showing Circulating tumor microemboli (CTM) and CTC expressing a mesenchymal marker with absence of epithelial markers.

CONCLUSIONS

This case report study shows the interest of a comparative and kinetic analysis of different methods for CTCs detection combined with their evaluation according to the clinical follow up. Our results should open up an area for future research and validation in larger clinical cohorts.

Prognostic value of circulating tumor cells in patients with pancreatic cancer: a meta-analysis

Increasing scientific evidences suggest that circulating tumor cells (CTC) in peripheral blood may be a powerful predictor of survival in patients with pancreatic cancer. However, many existing studies have yielded inconclusive results. This meta-analysis aims to assess the prognostic value of CTC in patients with pancreatic cancer. An extensive literary search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, CNKI, and CBM databases from their inception through July 1, 2013. The meta-analysis was then performed using the Stata 12.0 software. Crude hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated under a fixed or random effect model. Nine cohort studies were included in this meta-analysis with a total of 623 pancreatic cancer patients. This number included 268 CTC-positive patients and 355 CTC-negative patients. Our meta-analysis revealed that patients in the CTC-positive group were significantly associated with poor progression-free survival (PFS) (HR = 1.89, 95% CI = 1.25-4.00, P < 0.001). Furthermore, pancreatic cancer patients in the CTC-positive group also showed worse overall survival (OS) than those in the CTC-negative group (HR = 1.23, 95% CI = 0.88-2.08, P < 0.001). Subgroup analysis by ethnicity indicated that CTC-positive patients had poor OS among both Asian and Caucasian populations (all P < 0.05). Further subgroup analyses by detection and treatment methods also suggested that CTC-positive patients showed worser OS than CTC-negative patients in the majority of subgroups (all P < 0.05). No publication bias was detected in this meta-analysis. In conclusion, our meta-analysis suggests that CTC-positive pancreatic cancer patients may have worser PFS and OS than CTC-negative patients. Detection of CTC in peripheral blood may be a promising biomarker for the detection and prognosis of pancreatic cancer.

Colorectal cancer diagnostics: biomarkers, cell-free DNA, circulating tumor cells and defining heterogeneous populations by single-cell analysis

Reliable biomarkers are needed to guide treatment of colorectal cancer, as well as for surveillance to detect recurrence and monitor therapeutic response. In this review, the authors discuss the use of various biomarkers in addition to serum carcinoembryonic antigen, the current surveillance method for metastatic recurrence after resection. The clinical relevance of mutations including microsatellite instability, KRAS, BRAF and SMAD4 is addressed. The role of circulating tumor cells and cell-free DNA with regards to their implementation into clinical use is discussed, as well as how single-cell analysis may fit into a monitoring program. The detection and characterization of circulating tumor cells and cell-free DNA in colorectal cancer patients will not only improve the understanding of the development of metastasis, but may also supplant the use of other biomarkers.

Are morphological criteria sufficient for the identification of circulating tumor cells in renal cancer?

Background

Single circulating tumor cells (CTCs) or circulating tumor microemboli (CTMs) are potential biomarkers of renal cell cancer (RCC), however studies of CTCs/CTMs in RCC are limited. In this pilot study we aimed to evaluate a novel blood filtration technique suited for cytomorphological classification, immunocytochemical and molecular characterization of filtered, so called circulating non-hematologic cells (CNHCs) - putative CTCs/CTMs - in patients with RCC.

Methods

Blood of 40 patients with renal tumors was subjected to ScreenCell® filtration. CNHCs were classified according to cytomorphological criteria. Immunocytochemical analysis was performed with antibodies against CD45, CD31 and carbonic anhydrase IX (CAIX, a RCC marker). DNA of selected CNHCs and respective primary tumors was analysed by array-CGH.

Results

CNHC-clusters with malignant or uncertain malignant cytomorphological features - putative CTMs - were negative for CD45, positive for CD31, while only 6% were CAIX positive. Array-CGH revealed that 83% of malignant and uncertain malignant cells did represent with a balanced genome whereas 17% presented genomic DNA imbalances which did not match the aberrations of the primary tumors. Putative single CTCs were negative for CD45, 33% were positive for CD31 and 56% were positive for CAIX.

Conclusions

The majority of CNHC-clusters, putative CTMs, retrieved by ScreenCell® filtration may be of endothelial origin. Morphological criteria seem to be insufficient to distinguish malignant from non-malignant cells in renal cancer.