Flow cytometric analysis of CK19 expression in the peripheral blood of breast carcinoma patients: relevance for circulating tumor cell detection

Quantitative CK19 biomarker detection in breast cancer cell lines

Cytokeratin19 (CK19) was detected as the most related marker for circulating tumor cells, which was assessed in specific cell lines. MCF7, SKBR3, T47D, and MDA-MB-231, and HeLa cell line as negative control were used. CK19 expression was confirmed by using mouse monoclonal anti-human CK19 antibody. CK19 detection in MDA-MB-231 was not observed. CK19 marker expression was compared in T47D, MCF7, and SKBR3 cell lines. T47D and MCF7 belonged to the luminal subtype of breast cancer (BC) that CK19 expression regulated with an ER marker. SKBR3 belonged to the HER2 positive subtype of BC. However, MDA-MB-231 belonged to the claudin-low subtype of BC that lack of CK19 expression strongly is related to negative ER, PR, and HER2. Therefore, there are not only quantitative differences in CK19 expression, but its expression could also link to the other markers of BC that should be considered in the molecular classification of breast carcinoma. Different expression levels related to cell classification could be useful in the prognosis and treatment of cancers with epithelial origins.

Assessment of circulating tumor cells in peripheral blood using flow cytometry in patients with surgery for colorectal cancer – review

Introduction: Colorectal cancer (CRC) is the third most common neoplasia in the world. Circulating tumor cells (CTC) have a prognostic value and can be useful in monitoring solid neoplasia. Only one method for CTC identification has received the approval and this is the CellSearch® system based on the immunomagnetic separation. Multiple markers are used in CTC identification, as epithelial markers and cytokeratines. CTC identification in peripheral blood is associated with a worse prognostic and reduced free survival in CRC.

Material and methods: We performed a systematic search in PubMed database for articles that reports the circulating tumor cells in CRC until July 2019. We selected studies in English and French and the main words used for search were ‘circulating tumor cells’, ‘colorectal cancer’, ‘colon cancer’, ‘rectal cancer’, ‘flow cytometry’, ‘peripheral blood’. We included studies with more than 10 patients, where samples were collected from the blood in relation with surgery and flow cytometry was used as analyzing technique.

Results: We included 7 studies in final analysis, that showed in flow cytometry analysis a cut-off value of CTC that can vary from 2-4 CTC/ 7.5 ml peripheral blood with a sensitivity of 50.8% and specificity of 95%. Patients with positive CTC were associated with higher T stage and positive lymph nodes, with a worse overall survival (OS) and disease free survival (DFS) comparing with negative patients.

Conclusion: CTC are considered to be a prognostic factor who needs more validation studies in order to be included in the clinical practice.

Enrichment and detection of circulating tumor cells by immunomagnetic beads and flow cytometry

OBJECTIVE

The purpose of the article is to establish a quick enrichment and detection method using immunomagnetic beads and flow cytometry to analyze circulating tumor cells (CTCs) in the peripheral blood.

RESULTS

After incubation with CD326-PE and CD45-APC antibodies, more than 60% MCF7 cells in M-Buffer could be detected while less than 10% of the same cells could be detected by flow cytometry (FCM) if spiked into blood. However, in combination with CD326 and CD45 immunomagnetic beads, detection rate of MCF7 cells in blood reached 57%. For circulating tumor cells, enrichment by CD326 and CD45 immunomagnetic beads improve the detection rate from nearly undetectable to more than 24.14%.

CONCLUSIONS

Live CTCs in peripheral blood can be effectively and sensitively detected by using a combination of immunomagnetic beads (CD45 and CD326) and flow cytometry.

Circulating Tumor Cells Detection in Patients with Early Breast Cancer Using MACS Immunomagnetic Flow Cytometry

BACKGROUND

Circulating Tumor Cells (CTCs) detection in peripheral blood of epithelial cancer patients is an indicator of the presence of primary tumors and metastasis. The CTC phenotype detection uses epithelial markers in defining, detecting, and isolating CTCs. Circulating cell-separation technologies, with the epithelial origin, can be identified by epithelial biomarkers, with different techniques such as flow cytometry. The purpose of this study was to evaluate the expression of molecular Cytokeratins (CKs), CK7, CK8, CK18, CK19 (Pan-CK) and Epithelial Cell Adhesion Molecule (EpCAM) markers for CTC detection.

METHODS

The Magnetic Activated Cell Sorting (MACS) was used to identify CTCs in the blood of patients. Specific antibodies to EpCAM and Pan-CK were used and analyzed by flow cytometry. In this study, 35 blood samples of patients with breast cancer were assessed before any treatment and 35 healthy blood samples as the control were evaluated.

RESULTS

Expression of CK markers in the peripheral blood of breast cancer patients was statistically significant with p≤0.05, specifically at stages II-IV, but it was not significant in patients at stage I and healthy controls. Biomarkers expression in the blood of patients and healthy controls was assessed along with the pathologic characteristics of patients.

CONCLUSION

CTC assessment by flow cytometry in patients with breast cancer could not only be used for detection but also can be considered as a source of specific and subjective evaluation for monitoring the therapy. Besides, the sensitivity and specificity of CTC detection were shown that could be enhanced by specific CK markers.

Less micrometastatic risk related to circulating tumor cells after endoscopic breast cancer surgery compared to open surgery

BACKGROUND

Increase of circulating tumor cells (CTCs) has been found after surgery for various carcinomas but not confirmed for breast cancer, and whether endoscopic surgery confers identical effect to CTCs as open surgery did is not clear. The present study aimed to investigate whether CTCs increase after surgery and whether there is a difference between open surgery and endoscopic surgery.

METHODS

Pre- and postoperative peripheral blood (5 mL) obtained from 110 female patients with operable breast cancer (53 underwent endoscopic surgery, 57 underwent open radical mastectomy). Quantitative real-time reverse transcription-PCR was done to detect cytokeratin 19 mRNA-positive CTC. CTC detection rate, cell number and the increase after surgery (named micrometastasis) were compared between the two groups.

RESULTS

In the open group, CTC positive rate before and after surgery were 22.81 and 33.33%; median CTC number before and after surgery were 0.21 and 0.43 and 17 patients (29.82%) had increased micrometastatic risk. In the endoscopic group, CTC positive rate before and after surgery were 24.53 and 28.30%; median CTC number before and after surgery were 0.27 and 0.36, and 8 patients (15.09%) had increased micrometastatic risk. There was a suggestive higher postoperative CTC detection rate and CTC number and a significant increased postoperation micrometastatic risk was observed in the open group compared to the endoscopic group (OR = 3.19, 95%CI: 1.05-9.65) after adjustment for clinicopathologic characteristics.

DISCUSSION

CTC tends to increase in breast cancer patients after surgery, and the micrometastatic risk was higher for open surgery compared to endoscopic surgery.

TRIAL REGISTRATION

This study was prospectively registered at Chinese Clinical Trial Register (ChiCTR-OCH-10000859, 24 April 2010).

EpCAM-based Flow Cytometric Detection of Circulating Tumor Cells in Gallbladder Carcinoma Cases

Purpose:

Liquid biopsy has entered the arena of cancer diagnostics in the past decade and detection of circulating tumor cells (CTC) is one diagnostic component. CTCs in gallbladder cancer (GBC) have hitherto not been comprehensively analysed.

Methods and Results:

The current study focused on the diagnostic role of CTCs in 27 cases of treatment-naive GBC and 6 normal controls as well as 6 cases of cholecystitis. An EasySep kit featuring negative immunomagnetic bead separation and flow cytometric detection of EpCAM positive and CD45 negative cells revealed CTCs in 25 of the 27 cases. At a cut-off point of ≥1, the CTC count discriminated GBC from controls with a sensitivity, specificity and diagnostic accuracy of 92.6%, 91.7% and 92.3%, respectively. CTC levels in turn correlated significantly with clinico-pathological parameters of cases in terms of known prognostic indicators, with significant diagnostic potential at a cut-off point of >4, to discriminate disease stage I and II vs. III and IV GBC. With a cut-off of >3, the CTC count discriminated tumor stages I and II vs. III and IV and at >6 CTCs could discriminate metastatic vs. non metastatic GBCs with a sensitivity, specificity and diagnostic accuracy of 55. 6%, 100.0% and 85.2, respectively. A review of CTC in pancreatico-biliary malignancies is included.

Conclusion:

Detection and quantification of CTCs may serve as a non-invasive biomarker for GBC diagnosis in correlation with radiological studies.

Circulating Tumor Cells and Implications of the Epithelial-to-Mesenchymal Transition

The majority of cancer-related deaths result from metastasis, the process by which cancer cells escape the primary tumor site and enter into the blood circulation in order to disseminate to secondary locations throughout the body. Tumor cells found within the circulation are referred to as circulating tumor cells (CTCs), and their detection and enumeration correlate with poor prognosis. The epithelial-to-mesenchymal transition (EMT) is a dynamic process that imparts epithelial cells with mesenchymal-like properties, thus facilitating tumor cell dissemination and contributing to metastasis. However, EMT also results in the downregulation of various epithelial proteins typically utilized by CTC technologies for enrichment and detection of these rare cells, resulting in reduced detection of some CTCs, potentially those with a more metastatic phenotype. In addition to the current clinical role of CTCs as a prognostic biomarker, they also have potential as a predictive biomarker via CTC characterization. However, CTC characterization is complicated by the unknown biological significance of CTCs possessing an EMT-like phenotype, and the ability to capture and understand this CTC subpopulation is an essential step in the utilization of CTCs for patient management. This chapter will review the process of EMT and its contribution to metastasis; discusses current and future clinical applications of CTCs; and describes both traditional and novel methods for CTC enrichment, detection, and characterization with a specific focus on CTCs with an EMT phenotype.

Expression and Clinical Significance of Cytokeratin-19 and Thymidine Kinase-1 in Advanced Gastrointestinal Cancer

Background:

As the clinical value of cytokeratin-19 (CK19) and thymidine kinase-1 (TK1) in advanced gastrointestinal cancer remains controversial, we investigated their expression and clinical significance in this disease.

Methods:

A total of 171 advanced gastrointestinal cancer patients were prospectively enrolled in this study. The mRNA level of CK19 was detected using quantitative real-time reverse transcription-polymerase chain reaction (PCR) in all patients, along with a control group of fifty healthy individuals. Furthermore, detection of TK1 protein was carried out in 96 patients using a chemiluminescence dot blot assay. The primary endpoint was overall survival (OS) time.

Results:

Positive CK19 mRNA expression was detected in 74 (43.3%) of the 171 patients and positive TK1 expression was detected in 66 (68.8%) of the 96 patients. Furthermore, of the 96 patients, 36 (37.5%) were positive for both TK1 protein and CK19 mRNA, 30 (31.3%) were negative for TK1 protein, and 15 (15.6%) were negative for TK1 protein and positive for CK19 mRNA. The results indicated that patients who were positive for CK19 mRNA expression had significantly shorter OS times than those who were negative for it (median OS 7.7 vs. 9.7 months, respectively; P = 0.02). Moreover, patients who were positive for CK19 mRNA and TK1 protein expression had shorter OS times (median OS 6.1 months) than those who were positive for CK19 mRNA and negative for TK1 protein expression (median OS 9.1 months; P = 0.028). Positive CK19 mRNA expression was significantly associated with shorter OS in the univariate analysis (P = 0.027). Based on a multivariate Cox regression analysis, CK19 mRNA together with TK1 protein expression (P = 0.024) was an independent predictor for OS in gastrointestinal cancer patients.

Conclusions:

Our results suggest that positive expression of CK19 mRNA and TK1 protein is closely correlated with poor prognosis in advanced gastrointestinal cancer. Furthermore, both CK19 and TK1 are possible gastrointestinal cancer biomarkers.

Current approaches for avoiding the limitations of circulating tumor cells detection methods-implications for diagnosis and treatment of patients with solid tumors

Eight million people die of cancer each year and 90% of deaths are caused by systemic disease. Circulating tumor cells (CTCs) contribute to the formation of metastases and thus are the subject of extensive research and an abiding interest to biotechnology and pharmaceutical companies. Recent technological advances have resulted in greatly improved CTC detection, enumeration, expansion, and culture methods. However, despite the fact that nearly 150 years have passed since the first detection and description of CTCs in human blood and enormous technological progress that has taken place in this field, especially within the last decade, few CTC detection methods have been approved for routine clinical use. This reflects the substantial methodological problems related to the nature of these cells, their heterogeneity, and diverse metastatic potential. Here, we provide an overview of CTC phenotypes, including the plasticity of CTCs and the relevance of inflammation and cell fusion phenomena for CTC biology. We also review the literature on CTC detection methodology-its recent improvements, clinical significance, and efforts of its clinical application in cancer patients management. At present, CTC detection remains a challenging diagnostic approach as a result of numerous current methodological limitations. This is especially problematic during the early stages of the disease due to the small numbers of CTCs released into the blood of cancer patients. Nonetheless, the rapid development of novel techniques of CTC detection and enumeration in peripheral blood is expected to expedite their implementation in the clinical setting. It is of utmost importance to understand the biology of CTCs and their distinct populations as a prerequisite for achieving this ultimate goal.

Notes for developing a molecular test for the full characterization of circulating tumor cells

The proved association between the circulating tumor cell (CTC) levels and the patients' survival parameters has been growing interest to investigate the molecular profile of these neoplastic cells among which hide out precursors capable of initiating a new distant metastatic lesion. The full characterization of the tumor cells in peripheral blood of cancer patients is expected to be of help for understanding and (prospectively) for counteracting the metastatic process. The major hitch that is hampering the successful gaining of this result is the lack of a consensus onto standard operating procedures (SOPs) for performing what we generally define as the "liquid biopsy". Here we review the more recent acquisitions in the analysis of CTCs and tumor related nucleic acids, looking to the main open questions that are hampering their definitive employ in the routine clinical practice.

Methods for detecting circulating cancer stem cells (CCSCs) as a novel approach for diagnosis of colon cancer relapse/metastasis

Cancer stem cells (CSCs) are believed to be resistant to currently available therapies and may be responsible for relapse of cancer in patients. Measuring circulating tumor cells (CTCs) in the blood of patients has emerged as a non-invasive diagnostic procedure for screening patients who may be at high risk for developing metastatic cancers or relapse of the cancer disease. However, accurate detection of CTCs has remained a problem, as epithelial-cell markers used to date are not always reliable for detecting CTCs, especially during epithelial-mesenchymal transition. As CSCs are required to initiate metastatic tumors, our goal was to optimize and standardize a method for identifying circulating CSCs (CCSCs) in patients, using established CSC markers. Here, we report for the first time the detection of CCSCs in the blood of athymic nude mice, bearing metastatic tumors, and in the blood of patients positive for colonic adenocarcinomas. Using a simple and non-expensive method, we isolated a relatively pure population of CSCs (CD45-/CK19+), free of red blood cells and largely free of contaminating CD45+ white blood cells. Enriched CCSCs from patients with colon adenocarcinomas had a malignant phenotype and co-expressed CSC markers (DCLK1/LGR5) with CD44/Annexin A2. CSCs were not found in the blood of non-cancer patients, free of colonic growths. Enriched CCSCs from colon cancer patients grew primary spheroids, suggesting the presence of tumor-initiating cells in the blood of these patients. In conclusion, we have developed a novel diagnostic assay for detecting CSCs in circulation, which may more accurately predict the risk of relapse or metastatic disease in patients. As CSCs can potentially initiate metastatic growths, patients positive for CCSCs can be treated with inhibitory agents that selectively target CSCs, besides conventional treatments, to reduce the risk of relapse/metastatic disease for improving clinical outcomes.

Recent advances in the molecular characterization of circulating tumor cells

Although circulating tumor cells (CTCs) were first observed over a century ago, lack of sensitive methodology precluded detailed study of these cells until recently. However, technological advances have now facilitated the identification, enumeration, and characterization of CTCs using a variety of methods. The majority of evidence supporting the use of CTCs in clinical decision-making has been related to enumeration using the CellSearch® system and correlation with prognosis. Growing evidence also suggests that CTC monitoring can provide an early indication of patient treatment response based on comparison of CTC levels before and after therapy. However, perhaps the greatest potential that CTCs hold for oncology lies at the level of molecular characterization. Clinical treatment decisions may be more effective if they are based on molecular characteristics of metastatic cells rather than on those of the primary tumor alone. Molecular characterization of CTCs (which can be repeatedly isolated in a minimally invasive fashion) provides the opportunity for a "real-time liquid biopsy" that allows assessment of genetic drift, investigation of molecular disease evolution, and identification of actionable genomic characteristics. This review focuses on recent advances in this area, including approaches involving immunophenotyping, fluorescence in situ hybridization (FISH), multiplex RT-PCR, microarray, and genomic sequencing.

Clinical application of circulating tumor cells in breast cancer

Circulating tumor cells (CTCs) play a major role in the metastatic spread of breast cancer. CTC detection has proven to be an important parameter for predicting progression free and overall survival. Collection of CTCs is minimally invasive and can be performed more often than disseminated tumor cell (DTC) collection from bone marrow, thus providing a real-time "liquid biopsy". In this review, the most important techniques for enrichment and detection of CTCs are discussed for clinical application in low and higher staged breast cancer, as well as the genetic and molecular characterization of CTCs. For CTCs, the use of immunology-based enrichment techniques with multiple antibodies is recommended in a clinical setting, as well as the use of cytometric detection techniques, combined with RT-PCR for confirmation. Special attention is given to the value of cancer stem cell (CSC) activity, which may be the main cause of ineffectiveness of the control over metastatic lesions due to intratumor heterogeneity. Accumulating information on CSCs offers new paradigms to generate effective targets for the treatment of metastatic disease. Genetic and molecular characterization of CTCs has potential to stratify patients for optimal personalized treatment regimens. CTCs can be used for monitoring patients during treatment schedules.

Advances of lab-on-a-chip in isolation, detection and post-processing of circulating tumour cells

Circulating tumour cells (CTCs) are shed by primary tumours and are found in the peripheral blood of patients with metastatic cancers. Recent studies have shown that the number of CTCs corresponds with disease severity and prognosis. Therefore, detection and further functional analysis of CTCs are important for biomedical science, early diagnosis of cancer metastasis and tracking treatment efficacy in cancer patients, especially in point-of-care applications. Over the last few years, there has been an increasing shift towards not only capturing and detecting these rare cells, but also ensuring their viability for post-processing, such as cell culture and genetic analysis. High throughput lab-on-a-chip (LOC) has been fuelled up to process and analyse heterogeneous real patient samples while gaining profound insights for cancer biology. In this review, we highlight how miniaturisation strategies together with nanotechnologies have been used to advance LOC for capturing, separating, enriching and detecting different CTCs efficiently, while meeting the challenges of cell viability, high throughput multiplex or single-cell detection and post-processing. We begin this survey with an introduction to CTC biology, followed by description of the use of various materials, microstructures and nanostructures for design of LOC to achieve miniaturisation, as well as how various CTC capture or separation strategies can enhance cell capture and enrichment efficiencies, purity and viability. The significant progress of various nanotechnologies-based detection techniques to achieve high sensitivities and low detection limits for viable CTCs and/or to enable CTC post-processing are presented and the fundamental insights are also discussed. Finally, the challenges and perspectives of the technologies are enumerated.

Enrichment, detection and clinical significance of circulating tumor cells

Circulating Tumor Cells (CTCs) are shed from primary or secondary tumors into blood circulation. Accessing and analyzing these cells provides a non-invasive alternative to tissue biopsy. CTCs are estimated to be as few as 1 cell among a few million WBCs and few billion RBCs in 1 ml of patient blood and are rarely found in healthy individuals. CTCs are FDA approved for prognosis of the major cancers, namely, Breast, Colon and Prostate. Currently, more than 400 clinical trials are ongoing to establish their clinical significance beyond prognosis, such as, therapy selection and companion diagnostics. Understanding the clinical relevance of CTCs typically involves isolation, detection and molecular characterization of cells, ideally at single cell level. The need for highly reliable, standardized and robust methodologies for isolating and analyzing CTCs has been widely expressed by clinical thought leaders. In the last decade, numerous academic and commercial technology platforms for isolation and analysis of CTCs have been reported. A recent market report highlighted the presence of more than 100 companies offering products and services related to CTCs. This review aims to capture the state of the art and examines the technical merits and limitations of contemporary technologies for clinical use.

Markers of circulating breast cancer cells

The detection of circulating tumor cells (CTC) aids in diagnosis of disease, prognosis, disease recurrence, and therapeutic response. The molecular aspects of metastasis are reviewed including its relevance in the identification and characterization of putative markers that may be useful in the detection thereof. Also discussed are methods for CTC enrichment using molecular strategies. The clinical application of CTC in the metastatic disease process is also summarized.

[Advances in research on circulating tumor cells in lung cancer]

转移和复发是肺癌患者死亡的主要原因。研究发现循环肿瘤细胞（circulating tumor cells, CTCs）在肺癌转移和复发中起着重要作用。而且随着靶向治疗的不断进步，对于晚期无法取得肺癌实体组织的患者，CTCs作为一种肺癌组织替代物可以决定治疗方案。所以CTCs在早期发现肺癌患者的微转移、检测肿瘤复发、评估预后和选择个体化治疗方案方面有着重要作用。本文针对CTCs的研究进展及肺癌领域的应用进行综述。

Single-domain antibodies: a versatile and rich source of binders for breast cancer diagnostic approaches

Noninvasive early detection of breast cancer through the use of biomarkers is urgently needed since the risk of recurrence, morbidity, and mortality is closely related to disease stage at the time of primary surgery. A crucial issue in this approach is the availability of relevant markers and corresponding monoclonal antibodies suitable for the development of effective immunodiagnostic modalities. The identification of such markers from human pathological lesions and the isolation of specific antibodies using conventional approaches remain major challenges. Camelids produce functional antibodies devoid of light chains in which the single N-terminal domain of the heavy chain is fully capable of antigen binding. When produced as an independent domain, these so-called single-domain antibody fragments (sdAbs) or nanobodies have several advantages for biotechnological applications owing to their unique properties of size (13 kDa), stability, solubility, and expression yield. In this work, we have generated phage display libraries from animals immunized with breast cancer biopsies. These libraries were used to isolate sdAbs against known and relevant antigens such as HER2, or several cancer-specific sdAbs against unknown targets. We describe the identification of one these targets, cytokeratin 19, using affinity purification in combination with mass spectrometry. Some of these sdAbs were used in several straightforward diagnostic applications such as immunohistochemical analysis of tumor samples, multiplexed cytometric bead array analysis of crude samples, or an immune enrichment procedure of rare cells. Here, we demonstrate that phage display-based selection of single-domain antibodies is an efficient and high-throughput compatible approach to generate binders with excellent characteristics for the fast development of diagnostic and prognostic modalities.

Clinical significance of stanniocalcin-1 detected in peripheral blood and bone marrow of esophageal squamous cell carcinoma patients

Background

Stanniocalcin-1 (STC-1) is a potential marker of disseminated tumor cells (DTCs). The aim of this study was to examine STC-1 expression in peripheral blood (PB) and bone marrow (BM) of esophageal squamous cell carcinoma (ESCC) patients, and to evaluate its clinical significance.

Methods

A total of 85 ESCC patients treated with radical resection were enrolled in this study. Immunohistochemistry was used to detect STC-1 protein expression in ESCC tissues. Nested RT-PCR was used to detect STC-1 mRNA expression in PB and BM.

Results

There were 71 cases (83.5%) showed a higher level of STC-1 protein expression in tumor tissues than in adjacent normal tissues (P < 0.001). Furthermore, the frequencies of STC-1 mRNA expression detected in PB and BM were 37.6% (32/85) and 21.2% (18/85), respectively, and together increased sensitivity to 48.2% (41/85), which was much higher than that in patients with benign esophageal disease (5.0%, 2/40, P < 0.001). In addition, STC-1 mRNA expression either in PB or BM was correlated with lymph metastasis, advanced stage and adverse 2-year progression free survival (PFS). In a multivariate analysis using the Cox proportional hazard model, STC-1 expression in PB and/or BM was an independent unfavorable prognostic factor for ESCC, apart from lymph metastasis and clinical stage.

Conclusions

STC-1 mRNA expression is a reliable marker for detection of DTCs in PB and BM of ESCC patients, and STC-1-positive DTCs may be a promising tool for diagnosis and prognosis assessment in ESCC.

Detection of circulating tumor cells and tumor stem cells in patients with breast cancer by using flow cytometry: a valuable tool for diagnosis and prognosis evaluation

Circulating tumor stem cells (CTSC), a subpopulation of circulating tumor cells (CTC), may lead to recurrent diseases. The aim of this study was to detect CTC (CD45(-)EpCAM(+)) and CTSC (CD45(-)EpCAM(+)CD44(+)CD24(-)) of breast cancer (BC) patients, as well as to explore their clinical relevance. CTC and CTSC in peripheral blood (PB) of 45 female BC patients were detected by using flow cytometry (FCM). SKBR-3 cells were mixed with MNC of four healthy volunteers at different ratios in order to evaluate the sensitivity of FCM. Real-time quantitative polymerase chain reaction (QRT-PCR) was conducted and compared with FCM. The expression of EPCAM between CTC < 50 and CTC ≥ 50 groups (19.98 ± 23.93 versus 29.46 ± 29.27 × 10(-5)), and the expression of CD44 between CTSC negative and positive groups (0.85 ± 0.91 versus 0.81 ± 0.75) were statistically the same. FCM had higher specificity than QRT-PCR. Statistical differences were obtained between CTC < 50 and CTC ≥ 50 groups among different TNM stages, histology stages, estrogen receptor (ER) status and progesterone receptor (PR) status (P < 0.05). Statistical differences between CTSC negative and positive groups within different TNM stages and regional lymph node metastasis (RLNM) status (P < 0.05) were also obtained. Moreover, the percentage of CTC on CD45 negative cells (CD45(-)C) among different clinical pathology was statistically different, P = 0.000. Additionally, the percentage of CTSC on CD45(-)C with TNM stage was rising (0: 0.00 ± 0.00‰, I: 0.03 ± 0.05‰, II: 0.06 ± 0.14‰, III: 0.10 ± 0.09‰, IV: 0.29 ± 0.35‰, P = 0.034). Statistical difference in the percentage of CTSC on CD45(-)C among different RLNM status (P = 0.001) was also obtained. FCM to detect CTC and CTSC may be used to diagnose disease at early stage, to guide clinical therapy or to predict prognosis.

Fluorescent metal nanoshell and CK19 detection on single cell image

In this article, we report the synthesis strategy and optical properties of a novel type of fluorescence metal nanoshell when it was used as imaging agent for fluorescence cell imaging. The metal nanoshells were made with 40 nm silica cores and 10nm silver shells. Unlike typical fluorescence metal nanoshells which contain the organic dyes in the cores, novel metal nanoshells were composed of Cy5-labelled monoclonal anti-CK19 antibodies (mAbs) on the external surfaces of shells. Optical measurements to the single nanoparticles showed that in comparison with the metal free labelled mAbs, the mAb-Ag complexes displayed significantly enhanced emission intensity and dramatically shortened lifetime due to near-field interactions of fluorophores with metal. These metal nanoshells were found to be able to immunoreact with target cytokeratin 19 (CK19) molecules on the surfaces of LNCAP and HeLa cells. Fluorescence cell images were recorded on a time-resolved confocal microscope. The emissions from the metal nanoprobes could be clearly isolated from the cellular autofluorescence backgrounds on the cell images as either individuals or small clusters due to their stronger emission intensities and shorter lifetimes. These emission signals could also be precisely counted on single cell images. The count number may provide an approach for quantifying the target molecules in the cells.

Circulating tumor cells: advances in detection methods, biological issues, and clinical relevance

BACKGROUND

Circulating tumor cells (CTCs) have long been considered a reflection of tumor aggressiveness. Hematogenous spreading of CTCs from a primary tumor is a crucial step in the metastasis cascade, which leads ultimately to the formation of overt metastases. However, owing to the rarity of CTCs in peripheral blood, detecting these cells requires methods combined with high sensitivity and specificity, which sets tremendous challenges for the implementation of these assays into clinical routine.

METHODS

Generally, CTCs detection methods are composed of the following two steps: enrichment (isolation) process (morphological and immunological techniques) and detection (identification) process (cytometric and nucleic acid techniques), which may or may not be separate from enrichment. Genetic and molecular characterization of CTCs carried out by fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH), PCR-based techniques, and biomarker immunofluorescent staining extract more information about malignant profile, metastatic potential of CTCs, and the extent to which CTCs are genetically identical to the primary tumor.

RESULTS

Recent technical advances made it possible to detect CTCs. The efficacy of circulating tumor cell (CTC) detection among patients with solid malignancy has been investigated, which shows great potential to become a tool for real-time parameter of prognosis and serve as an early marker to assess the therapeutic response in overt cancers. Improvements in detection and characterization of CTCs will hopefully lead to refinement of clinical management of cancer patients.

CONCLUSION

This review addresses the majority of assays that have been published thus far, including the enrichment and detection steps and the markers used in these assays, accompanied by some biological issues of CTC and the results of clinical application harvested.

Enumeration, characterization, and collection of intact circulating tumor cells by cross contamination-free flow cytometry

Circulating tumor cells (CTC) are an important biomarker for several solid cancers. Most of the commercially available systems for enumeration of CTC are based on immunomagnetic enrichment of epithelial cell adhesion molecule (EpCAM/CD326)-expressing CTC before microscopic cell imaging or reverse-transcription PCR (RT-PCR). The aim of this study was to establish a practical method for enumeration of CTC using a novel flow cytometer that has a disposable microfluidic chip, which is designed to realize absolute cross contamination-free measurements and to collect the analyzed cell sample. Although the process of enumeration and labeling of CTC was optimized for this device, the simplified protocol described here could be applied to other flow cytometers. Cultured cancer cells spiked into normal blood were enriched using MACS® EpCAM-MicroBeads following cell labeling with an allophycocyanin (APC)-conjugated EpCAM mAb, instead of by intracellular staining of cytokeratins (CK). The EpCAM double-positive selection/labeling method allows enumeration of intact CTC, maintenance of cellular integrity, and the concomitant performance of a CTC viability test. The combination of the fine-tuned CTC enrichment process and the cytometric multicolor analysis resulted in a linear relationship between the output cell count and the input cell number from zero to hundreds of cells. In particular, a satisfactory signal/noise ratio was obtained by gate-exclusion of leukocyte signals using an anti-CD45 mAb. The entire process had little influence on the viability of the spiked lung cancer cell PC-9. Measured PC-9 and breast cancer MCF-7 cells bearing EpCAM-MicroBeads, APC-conjugated EpCAM mAb, and the DNA staining dye SYTO9 grew normally, demonstrating the potential usefulness of the collected samples for further studies. This intact CTC enumeration and analysis procedure (iCeap) would be of great benefit to clinicians by providing them with rapid stratification of antitumor therapy, and to basic researchers by permitting further molecular and cellular characterization of CTC.

Circulating tumor cells in breast cancer patients: an evolving role in patient prognosis and disease progression

In this paper, we examine the role of circulating tumor cells (CTCs) in breast cancer. CTCs are tumor cells present in the peripheral blood. They are found in many different carcinomas but are not present in patients with benign disease. Recent advances in theories regarding metastasis support the role of early release of tumor cells in the neoplastic process. Furthermore, it has been found that phenotypic variation exists between the primary tumor and CTCs. Of particular interest is the incongruency found between primary tumor and CTC HER2 status in both metastatic and early breast cancer. Overall, CTCs have been shown to be a poor prognostic marker in metastatic breast cancer. CTCs in early breast cancer are not as well studied, however, several studies suggest that the presence of CTCs in early breast cancer may also suggest a poorer prognosis. Studies are currently underway looking at the use of CTC level monitoring in order to guide changes in therapy.

Cytopathologic detection of circulating tumor cells using the isolation by size of epithelial tumor cell method: promises and pitfalls

Detection of circulating tumor cells (CTCs) morphologically may be a promising new approach in clinical oncology. We tested the reliability of a cytomorphologic approach to identify CTCs: 808 blood samples from patients with benign and malignant diseases and healthy volunteers were examined using the isolation by size of epithelial tumor cell (ISET) method. Cells having nonhematologic features (so-called circulating nonhematologic cells [CNHCs]) were classified into 3 categories: CNHCs with malignant features, CNHCs with uncertain malignant features, and CNHCs with benign features. CNHCs were found in 11.1% and 48.9% of patients with nonmalignant and malignant pathologies, respectively (P < .001). CNHCs with malignant features were observed in 5.3% and in 43.1% of patients with nonmalignant and malignant pathologies, respectively. Cytopathologic identification of CTCs using the ISET method represents a promising field for cytopathologists. The possibility of false-positive diagnosis stresses the need for using ancillary methods to improve this approach.

Gene expression of circulating tumour cells and its correlation with tumour stage in breast cancer patients

BACKGROUND

Breast cancer (BC) represents one of the leading causes of cancer related deaths worldwide. New tools for diagnostic staging and therapeutic monitoring are needed to improve individualized therapies and improve clinical outcome. The analyses of circulating tumour cells may provide important prognostic information in the clinical setting.

MATERIALS AND METHODS

Circulating tumour cells (CTC) of 63 BC patients were isolated from peripheral blood (PB) through immunomagnetic separation. Subsequently, RT-PCR or mPCR for the genes ga733.2, muc-1, c-erbB2, mgb-1, spdef and c-erbB2 were performed. Subsequently, expression data were correlated with the tumour stages. Fourteen healthy individuals served as controls.

RESULTS

Significant correlations with tumour stages were found in single gene analyses of ga733.2, muc-1 and in multi-gene analyses of ga733.2/muc-1/mgb1/ spdef. Furthermore, a significant correlation of Ca 15-3 and all studied genes was also observed.

CONCLUSION

Herein, we demonstrated a positive correlation of a gene signature consisting of ga733.2, muc-1, mgb1 and spdef and advanced stages of BC. Moreover, all studied genes and gene patterns revealed a significant correlation with Ca 15-3 positive cases.