Circulating tumor cells-new challenges ahead

The presence of circulating tumor cells (CTCs)2 was first described by Thomas Ashworth in 1869 (1). In 1889, Stephen Paget proposed in the first issue of The Lancet the “seed and soil ” hypothesis, according to which “metastasis depends on cross talk between se-lected cancer cells and specific organ microenviron-ment, ” a hypothesis revisitedmany years later by Isaiah Fidler (2). It tookmore than a century to recognize the critical role that CTCs play in the metastatic spread of carcinomas, that the detection of CTCs is associated with prognosis for many cancers (such as those of the breast, colon, and prostate), and that their enumera-tion is useful in follow-up (3). On the basis of these developments, the evaluation of CTCs now represents a promising new diagnostic tool, especially fo

Liquid biopsy in ovarian cancer

Ovarian cancer has the worst survival rate because it is typically diagnosed at advanced stage. Despite treatment, the disease commonly recurs due to chemo-resistance. Liquid biopsy, based on minimally invasive blood tests, has the advantage of following tumor evolution in real time, offering novel insights on cancer prevention and treatment. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), circulating cell-free microRNAs (cfmiRNAs) and circulating exosomes represent the major components of liquid biopsy. In this chapter, we provide an overview of recent research on CTCs, ctDNA, cfmiRNAs and exosomes in ovarian cancer. We also focus on the clinical value of liquid biopsy in early diagnosis, prognosis, treatment response, as well as screening in the general population. © 2020 Elsevier Inc

Simple spectrofluorometric determination of p-aminobenzoic and p- aminosalicylic acids in biological fluids by use of terbium-sensitized luminescence

A novel, sensitive, and selective method has been developed for determination of p-aminobenzoic (PABA) and p-aminosalicylic (PAS) acids in the N-benzoyl-L-tyrosyl-PABA/PAS test, PAS is measured as a ternary complex with terbium and EDTA (λ(ex) = 324 nm, λ(cm) = 546 nm) in alkaline aqueous solution (pH~ 12.6), whereas both compounds (PABA and PAS) are measured as ternary complexes with terbium and tri-n-octylphosphine oxide (λ(cs) = 292 nm, λ(cm) = 546 nm) in weakly acidic aqueous solution (pH~ 5.5). We investigated and implemented optimum conditions for formation of these complexes, yielding respective detection limits for PABA and PAS of 0.07 and 0.02 μmol/L and ranges of application of 0-10 and 0-40 μmol/L (final concentration). The method has been successfully applied to determinations of PABA and PAS in urine and, after alkaline hydrolysis, to determinations of PABA in serum that has been deproteinized with acetonitrile. Within-run imprecision of the PABA determination ranges from 0.8% to 4.2% for urine samples and from 3.9% to 8.2% for serum samples; day-to-day imprecision varies from 3.2% to 10% for serum samples

Circulating tumor cells in breast cancer: Detection systems, molecular characterization, and future challenges

BACKGROUND: Circulating tumor cell (CTC) analysis is a promising new diagnostic field for estimating the risk for metastatic relapse and metastatic progression in patients with cancer. CONTENT: Different analytical systems for CTC isolation and detection have been developed as immunocytochemical and molecular assays, most including separation steps by size or biological characteristics, such as expression of epithelial- or cancer-specific markers. Recent technical advancements in CTC detection and characterization include methods based on multiplex reverse-transcription quantitative PCR and approaches based on imaging and microfilter and microchip devices. New areas of research are directed toward developing novel assays for CTC molecular characterization. QC is an important issue for CTC analysis, and standardization of micrometastatic cell detection and characterization methodologies is important for the incorporation of CTCs into prospective clinical trials to test their clinical utility. The molecular characterization of CTCs can provide important information on the molecular and biological nature of these cells, such as the status of hormone receptors and epidermal and other growth factor receptor family members, and indications of stem-cell characteristics. This information is important for the identification of therapeutic targets and resistance mechanisms in CTCs as well as for the stratification of patients and real-time monitoring of systemic therapies. SUMMARY: CTC analysis can be used as a liquid biopsy approach for prognostic and predictive purposes in breast and other cancers. In this review we focus on state-of-the-art technology platforms for CTC isolation, imaging, and detection; QC of CTC analysis; and ongoing challenges for the molecular characterization of CTCs. © 2011 American Association for Clinical Chemistry

Circulating tumor cells as emerging tumor biomarkers in breast cancer

Circulating tumor cells (CTCs) provide unique information for the management of breast cancer patients, since their detection and monitoring is useful for prognosis, prediction of response to therapy, or monitoring clinical course in patients with localized or metastatic disease. Currently, the most practical application of CTCs is monitoring of patients with metastatic disease. Elevated CTC levels prior to initiation of a new systemic therapy are associated with a worse prognosis while persistently elevated CTC levels strongly suggest that the therapeutic regimen with which the patient is being treated is not working. New areas of research are directed toward developing novel sensitive assays for CTC molecular characterization. Molecular characterization of CTCs is very important for the future use of CTCs as targets of novel therapies. This review has focused on the presentation of recent data showing that CTCs are emerging as novel tumor biomarkers for prognostic and predictive purposes in breast cancer. © 2011 by Walter de Gruyter Berlin Boston

The Impact of Pre-analytical Factors on the Reliability of miRNA Measurements

Purpose of Review: In this review, we highlight the importance of using standardized procedures and protocols for circulating miRNA isolation, detection, and quantification, in order to establish their role as non-invasive biomarkers in the clinical setting. Recent Findings: Specific miRNAs have already been investigated as promising prognostic and diagnostic markers in various types of cancer. Circulating microRNAs detected in plasma are continuously and intensively explored as non-invasive prognostic and diagnostic markers in a variety of human diseases and mainly in cancer. These miRNAs are remarkably stable in biological fluids and their expression profiles have been shown to represent a compelling non-invasive biomarker for cancer diagnosis. Summary: Circulating miRNAs are remarkably stable, even in the extracellular environment with high RNAse activity. However, circulating miRNA quantitative measurements could be significantly influenced by several external and intra-individual factors. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Determination of kinetic parameters for 3α-Hydroxysteroid dehydrogenase using the five major bile acids and their conjugates as substrates and correlation with their structure and solubility

Kinetic parameters for 3α-hydroxysteroid dehydrogenase (3α-HSD) using the five major free bile acids and their glycine and taurine conjugates as substrates and β-nicotinamide adenine dinucleotide (β-NAD +) as coenzyme were determined from initial rate measurements. Four different mathematical methods were used for the evaluation of the results: (a) the double reciprocal plot, (b) the direct linear plot, (c) the Woolf plot and (d) the Scatchard plot methods. The determined kinetic parameters were correlated with the structure of the substrates (number of free hydroxy groups) and their absolute aqueous solubilities

Molecular assays for the detection and characterization of CTCS

Molecular characterization for circulating tumor cells (CTCs) can be used to better understand the biology of metastasis, to improve patient management and help to identify novel targets for biological therapies aimed to prevent metastatic relapse. New areas of research are directed towards developing novel sensitive assays for CTC molecular characterization. Towards this direction, molecular detection technologies that take advantage of the extreme sensitivity and specificity of PCR, offer many advantages, such as high sensitivity, specificity, and significant flexibility in the clinical lab setting, in terms of high-throughput analysis, multiplexing, and quality control issues. Using molecular assays, a variety of molecular markers such as multiple gene expression, DNA methylation markers, DNA mutations, and miRNAs have been detected and quantified in CTCs in various cancer types, enabling their molecular characterization. Here, we present the main molecular detection technologies currently used for CTC analysis and molecular characterization. © 2012 Springer-Verlag Berlin Heidelberg

Lung cancer epigenetics: Emerging biomarkers

Lung cancer is the leading cause of cancer-related deaths worldwide, and the 5-year survival rate is still very poor due to the scarcity of effective tools for early detection. The discovery of highly sensitive and specific biomarkers highlighting pathological changes early enough to allow clinical intervention is therefore of great importance. In the last decade, epigenetics and particularly research on DNA methylation have provided important information towards a better understanding of lung cancer pathogenesis. Novel and promising molecular biomarkers for diagnosis and prognosis of lung cancer are continuously emerging in this area, requiring further evaluation. This process includes extensive validation in prospective clinical trials before they can be routinely used in a clinical setting. This review summarizes the evidence on epigenetic biomarkers for lung cancer, focusing on DNA methylation. © 2013 Future Medicine Ltd

Circulating tumor cells as promising novel biomarkers in solid cancers

The presence of circulating tumor cells (CTCs) in peripheral blood can serve as a "liquid biopsy" approach and has thus emerged lately as one of the hottest fields in cancer research. CTCs can be isolated from blood in a non-invasive approach, and can be used to follow patients over time since these cells can provide significant information for a better understanding of tumor biology and tumor cell dissemination. CTC molecular characterization offers the unique potential to better understand the biology of metastasis and resistance to established therapies, and analysis of these cells presents a promising field for both advanced and early-stage patients. CTC detection, enumeration, and molecular characterization are very challenging since CTCs are rare, and the amount of available sample is very limited. Since detection of CTCs has been shown to be of considerable utility in the clinical management of patients with solid cancers, various analytical systems for their isolation and detection have been developed. New areas of research are directed towards developing novel assays for single-CTC isolation and molecular characterization. The clinical significance of CTCs has been evaluated in many types of solid cancers, and the CTC enumeration test in metastatic breast, colorectal, and prostate cancer was cleared by the FDA almost a decade ago. This review is mainly focused on the clinical potential of CTCs as novel biomarkers in 10 different types of solid cancers: breast, ovarian, prostate, lung, colorectal, hepatocellular carcinoma, pancreatic, head and neck, bladder cancer and melanoma. © 2014 Informa Healthcare USA Inc