Circulating tumor cells and circulating tumor DNA

Analysis of colorectal cancer-related mutations by liquid biopsy: Utility of circulating cell-free DNA and circulating tumor cells

We recruited 56 colorectal cancer patients and compared the mutational spectrum of tumor tissue DNA, circulating cell‐free DNA (ccfDNA) and circulating tumor cell (CTC) DNA (ctcDNA) to evaluate the potential of liquid biopsy to detect heterogeneity of cancer. Tumor tissue DNA, ccfDNA, and ctcDNA were extracted from each patient and analyzed using next‐generation sequencing (NGS) and digital PCR. To maximize yields of CTC, three antibodies were used in the capture process. From 34 untreated patients, 53 mutations were detected in tumor tissue DNA using NGS. Forty‐seven mutations were detected in ccfDNA, including 20 not detected in tissues. Sixteen mutations were detected in ctcDNA, including five not detected in tissues. In 12 patients (35.3%), mutations not found in tumor tissues were detected by liquid biopsy: nine (26.5%) in ccfDNA only and three (8.8%) in ctcDNA only. Combination analysis of the two liquid biopsy samples increased the sensitivity to detect heterogeneity. From 22 stage IV patients with RAS mutations in their primary tumors, RAS mutations were detected in 14 (63.6%) ccfDNA and in eight (36.4%) ctcDNA using digital PCR. Mutations not detected in primary tumors can be identified in ccfDNA and in ctcDNA, indicating the potential of liquid biopsy in complementing gene analysis. Combination analysis improves sensitivity. Sensitivity to detect cancer‐specific mutations is higher in ccfDNA compared with ctcDNA.

Alter circulating cell-free DNA variables in plasma of ovarian cancer patients

AIM

Liquid biopsy shows great potential in the fields of early diagnosis and prognosis in cancer. Ovarian cancer (OC) is the seventh most common cancer and the eighth most common cause of death from cancer in women. The early diagnosis of OC is vital for subsequent treatment and outcome. Here we investigated two markers: cell-free DNA concentration (cfDNA conc) and cell-free DNA integrity (cfDI) between OC patients and healthy controls.

METHODS

Age-matched OC patients and healthy controls were enrolled in this study. In total, there are 20 patients and 20 healthy controls. cfDNA conc and cfDI were calculated by arthrobacter luteus (ALU) gene using quantitative real-time polymerase chain reaction (PCR).

RESULTS

An increased cfDNA conc in OC patients compared to healthy controls was observed (mean cfDNA conc for OC patients: 1.98 ng/μL, for healthy control: 0.51 ng/μL, P = 0.02). For cfDI, the median value of OC patients is 0.49 while the median value of healthy control is 0.61 (P = 0.038). The diagnostic value of area under the curve was 0.86 for cfDNA conc and 0.72 for cfDI. When cfDNA conc and cfDI were combined, the diagnostic value was 0.90 which indicates a good diagnostic marker.

CONCLUSION

As few reports of cfDNA conc and cfDI differences between OC patients and healthy controls reported, our study shows increased cfDNA concentrations and decreased cfDI in OC patients compared to healthy controls. We also propose that cfDNA biomarkers can be potential diagnostic markers in ovarian cancer.

S100-EPISPOT: A New Tool to Detect Viable Circulating Melanoma Cells

Metastatic melanoma is one of the most aggressive and drug-resistant cancers with very poor overall survival. Circulating melanoma cells (CMCs) were first described in 1991. However, there is no general consensus on the clinical utility of CMC detection, largely due to conflicting results linked to the use of heterogeneous patient populations and different detection methods. Here, we developed a new EPithelial ImmunoSPOT (EPISPOT) assay to detect viable CMCs based on their secretion of the S100 protein (S100-EPISPOT). Then, we compared the results obtained with the S100-EPISPOT assay and the CellSearch^® CMC kit using blood samples from a homogeneous population of patients with metastatic melanoma. We found that S100-EPISPOT sensitivity was significantly higher than that of CellSearch^®. Specifically, the percentage of patients with ≥2 CMCs was significantly higher using S100-EPISPOT than CellSearch^® (48% and 21%, respectively; p = 0.0114). Concerning CMC prognostic value, only the CellSearch^® results showed a significant association with overall survival (p = 0.006). However, due to the higher sensitivity of the new S100-EPISPOT assay, it would be interesting to determine whether this functional test could be used in patients with non-metastatic melanoma for the early detection of tumor relapse and for monitoring the treatment response.

Design of a Targeted Sequencing Assay to Detect Rare Mutations in Circulating Tumor DNA

BACKGROUND

Qualitative and quantitative detection of circulating tumor DNA (ctDNA) is a liquid biopsy technology used for early cancer diagnosis. However, the plasma ctDNA content is extremely low, so it is difficult to detect somatic mutations of tumors using conventional sequencing methods. Target region sequencing (TRS) technology, through enrichment of the target genomic region followed by next generation sequencing, overcomes this challenge and has been widely used in ctDNA sequencing.

METHODS

We designed a ctDNA sequencing panel to capture 128 tumor genes, and tested the performance of the panel by running TRS for ctDNA of a clear cell renal cell carcinoma (ccRCC) patient and 12 breast cancer patients.

RESULTS

TRS using the new ctDNA panel at more than 500 × coverage depth achieved almost the same accuracy as traditional whole-exome sequencing (WES). PBRM1 p.L641V was detected in the plasma sample of the ccRCC patient with an allele frequency of 0.2%. The ctDNA of 12 breast cancer patients was sequenced at a depth of 500-fold, achieving 99.89% coverage; 34 genes were detected with mutations, including the drug target genes BRCA2, PTEN, TP53, APC, KDR, and NOTCH2.

CONCLUSIONS

This TRS new ctDNA panel can be used to detect mutations in cell-free DNA from multiple types of cancer.

Circulating Tumor Cells in Diagnosis and Treatment of Lung Cancer

Circulating tumor cells (CTCs), detached from the primary tumor or metastases and shed in the patient's bloodstream, represent a relatively easily obtainable sample of the cancer tissue that can indicate the actual state of cancer, and their evaluation can be repeated many times during the course of treatment. As part of liquid biopsy, evaluation of CTCs provides a lot of clinically relevant information, which reflects the actual, real-time conditions of the disease. CTCs can be used in cancer diagnosis or screening, real-time long-term disease monitoring and even therapy guidance. Their analysis can include their number, morphology, and biological features by using immunocytochemistry and all "-omic" technologies. This review describes methods of CTC isolation and potential clinical utilization in lung cancer.

Identification of mutations in circulating cell-free tumour DNA as a biomarker in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is increasing globally. Prognostic biomarkers are urgently needed to guide treatment and reduce mortality. Tumour-derived circulating cell-free DNA (ctDNA) is a novel, minimally invasive means of determining genetic alterations in cancer. We evaluate the accuracy of ctDNA as a biomarker in HCC.

METHODS

Plasma cell-free DNA, matched germline DNA and HCC tissue DNA were isolated from patients with HCC (n = 51) and liver cirrhosis (n = 10). Targeted, multiplex polymerase chain reaction ultra-deep sequencing was performed using a liver cancer-specific primer panel for genes ARID1A, ARID2, AXIN1, ATM, CTNNB1, HNF1A and TP53. Concordance of mutations in plasma ctDNA and HCC tissue DNA was determined, and associations with clinical outcomes were analysed.

RESULTS

Plasma cell-free DNA was detected in all samples. Lower plasma cell-free DNA levels were seen in Barcelona Clinic Liver Cancer (BCLC A compared with BCLC stage B/C/D (median concentration 122.89 ng/mL versus 168.21 ng/mL, p = 0.041). 29 mutations in the eight genes (21 unique mutations) were detected in 18/51 patients (35%), median 1.5 mutations per patient (interquartile range 1-2). Mutations were most frequently detected in ARID1A (11.7%), followed by CTNNB1 (7.8%) and TP53 (7.8%). In patients with matched tissue DNA, all mutations detected in plasma ctDNA detected were confirmed in HCC DNA; however, 71% of patients had mutations identified in HCC tissue DNA that were not detected in matched ctDNA.

CONCLUSION

ctDNA is quantifiable across all HCC stages and allows detection of mutations in key driver genes of hepatic carcinogenesis. This study demonstrates high specificity but low sensitivity of plasma ctDNA for detecting mutations in matched HCC tissue.

Dynamics of Minimal Residual Disease in Neuroblastoma Patients

Neuroblastoma is a common extracranial solid tumor of neural crest (NC) origin that accounts for up to 15% of all pediatric cancer deaths. The disease arises from a transient population of NC cells that undergo an epithelial-mesenchymal transition (EMT) and generate diverse cell-types and tissues. Patients with neuroblastoma are characterized by their extreme heterogeneity ranging from spontaneous regression to malignant progression. More than half of newly diagnosed patients present highly metastatic tumors and are stratified into a high-risk group with dismal outcome. As many as 20% of high-risk patients have residual disease that is refractory or progressive during induction chemotherapy. Although a majority of high-risk patients achieve remission, larger part of those patients has minimal residual disease (MRD) that causes relapse even after additional consolidation therapy. MRD is composed of drug-resistant tumor cells and dynamically presented as cancer stem cells (CSCs) in residual tumors, circulating tumor cells (CTCs) in peripheral blood (PB), and disseminated tumor cells (DTCs) in bone marrow (BM) and other metastatic sites. EMT appears to be a key mechanism for cancer cells to acquire MRD phenotypes and malignant aggressiveness. Due to the restricted availability of residual tumors, PB and BM have been used to isolate and analyze CTCs and DTCs to evaluate MRD in cancer patients. In addition, recent technical advances make it possible to use circulating tumor DNA (ctDNA) shed from tumor cells into PB for MRD evaluation. Because MRD can be detected by tumor-specific antigens, genetic or epigenetic changes, and mRNAs, numerous assays using different methods and samples have been reported to detect MRD in cancer patients. In contrast to the tumor-specific gene-rearrangement-positive acute lymphoblastic leukemia (ALL) and the oncogenic fusion-gene-positive chronic myelogenous leukemia (CML) and several solid tumors, the clinical significance of MRD remains to be established in neuroblastoma. Given the extreme heterogeneity of neuroblastoma, dynamics of MRD in neuroblastoma patients will hold a key to the clinical validation. In this review, we summarize the biology and detection methods of cancer MRD in general and evaluate the available assays and clinical significance of neuroblastoma MRD to clarify its dynamics in neuroblastoma patients.

Droplet digital PCR as a novel system for the detection of microRNA‑34b/c methylation in circulating DNA in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a rare malignancy arising from the pleura that is difficult to diagnose, contributing to its dismal prognosis. Previously, we reported that the degree of microRNA (miR)‑34b/c methylation in circulating DNA is associated with the development of MPM. Herein, we present a newly developed droplet digital PCR (ddPCR)‑based assay for the detection of miR‑34b/c methylation in circulating DNA in patients with MPM. We originally prepared two probes within a short amplicon of 60 bp, designing one from the positive strand and the other from the complementary strand. The two probes functioned cooperatively, and our established assay detected DNA methylation accurately in the preliminary validation. We subsequently verified this assay using clinical samples. Serum samples from 35 cases of MPM, 29 cases of pleural plaque and 10 healthy volunteers were collected from 3 different institutions and used in this study. We divided the samples into 2 groups (group A, n=33; group B, n=41). A receiver‑operating characteristic curve analysis using the samples in group A determined the optimal cut‑off value for the diagnosis of MPM, with a sensitivity of 76.9% and a specificity of 90%. On the other hand, the use of the same criterion yielded a sensitivity of 59.1% and a specificity of 100% in group B, and corresponding values of 65.7 and 94.9% for the entire cohort, indicating a moderate sensitivity and a high specificity. In addition, when the analysis was focused on stage II or more advanced MPM, the sensitivity improved to 81.8%, suggesting the possibility that the methylated allele frequency in MPM may be associated with the stage of disease progression. On the whole, the findings of this study indicate that miR‑34b/c methylation in circulating DNA is a promising biomarker for the prediction of disease progression in patients with MPM.

Application of Circulation Tumor Cells Detection in Diagnosis and Treatment of Breast Tumors

In recent years, the clinical application of circulating tumor cell (CTCs) detection has become one of the research hotspots in the field of precision medicine. CTCs detection is noninvasive, easy to obtain, can be repeatedly collected, and highly repeatable with other advantages. It not only can be a real-time comprehensive monitoring of cancer treatment but also can have a large number of applications, including early diagnosis of tumor, timely evaluation of efficacy, condition monitoring, resistance factor analysis, prognosis judgment, individualized treatment of tumors, drug guidance, and so on. At present, many large-scale clinical studies at home and abroad run through all stages of breast cancer diagnosis and treatment. For different treatment stages of breast cancer, the application value of CTCs detection is different. Compared with traditional detection methods, CTCs have advantages in dynamic monitoring of disease changes and efficacy evaluation in real-time. In the era of breast cancer classificational and individualized treatment, CTCs detection can provide patients with the most timely and optimized treatment plan.

The current role of circulating biomarkers in non-muscle invasive bladder cancer

Non-muscle invasive bladder cancer (NMIBC) is characterized by its high rate of disease recurrence and relevant disease progression rates. Up to today clinical models are insufficiently predicting outcomes for reliable patient counseling and treatment decision-making. This particularly is a serious problem in patients with high-risk NMIBC who are at high risk for failure of local treatment and thus candidates for early radical cystectomy or even systemic (neoadjuvant) chemotherapy. Next to its clinical variability, bladder cancer is genetically a highly heterogeneous disease. There is an essential need of biomarkers for improving clinical staging, real-time monitoring of disease with or without active treatment, as well as improved outcome prognostication. Liquid biopsies of circulating biomarkers in the blood and urine are promising non-invasive diagnostics that hold the potential facilitating these needs. In this review we report the latest data and evidence on cell-free circulating tumor desoxyribonucleic acid (ctDNA) and circulating tumor cells (CTC) in NMIBC. We summarize their current status in clinical diagnostics, discuss limitations and address future needs.

A microfluidic platform integrated with field-effect transistors for enumeration of circulating tumor cells

Circulating tumor cells (CTCs) are one of the promising cancer biomarkers whose concentrations are measured not only in the initial diagnostic stages, but also as treatment progresses. However, the existing methods for CTC detection are relatively time-consuming and labor-intensive. In this study, a new microfluidic platform integrated with field-effect transistors (FETs) and chambers for the trapping of CTCs was developed. This novel design could not only trap CTCs from whole blood samples, but also enumerate them via FET sensing of CTC-specific aptamer-CTC complexes. The FET output signal was experimentally found to increase with the increasing number of captured CTCs. More importantly, the enumeration of spiked CTCs in blood samples could be achieved in accordance with the signals measured on the FET devices. We therefore believe that this automated system could be a useful tool for enumeration of CTCs.

Low-cost thermophoretic profiling of extracellular-vesicle surface proteins for the early detection and classification of cancers

Non-invasive assays for early cancer screening are hampered by challenges in the isolation and profiling of circulating biomarkers. Here, we show that surface proteins from serum extracellular vesicles labelled with a panel of seven fluorescent aptamers can be profiled, via thermophoretic enrichment and linear discriminant analysis, for cancer detection and classification. In a cohort of 102 patients, including 6 cancer types at stages I-IV, the assay detected stage I cancers with 95% sensitivity (95% confidence interval (CI): 74-100%) and 100% specificity (95% CI: 80-100%), and classified the cancer type with an overall accuracy of 68% (95% CI: 59-77%). For patients who underwent prostate biopsies, the assay was superior to the analysis of prostate-specific antigen levels (area under the curve: 0.94 versus 0.68; 33 patients) for the discrimination of prostate cancer and benign prostate enlargement, and also in the assessment of biochemical cancer recurrence after radical prostatectomy. The assay is inexpensive, fast, and requires small serum volumes (<1 µl), and if validated in larger cohorts may facilitate cancer screening, classification and monitoring.

Molecular characterisation and liquid biomarkers in Carcinoma of Unknown Primary (CUP): taking the 'U' out of 'CUP'

Cancers of Unknown Primary (CUP) comprise a heterogeneous clinical entity of confirmed metastatic cancer where the primary site of origin is undetectable. It has a poor prognosis with limited treatment options. CUP is historically under-researched; however, understanding its biology has the potential to not only improve treatment and survival by implementation of biomarkers for patient management, but also to greatly contribute to our understanding of carcinogenesis and metastasis across all cancer types. Here we review the current advances in CUP research and explore the debated hypotheses underlying its biology. The evolution of molecular profiling and tissue-of-origin classifiers have the potential to transform the diagnosis, classification and therapeutic management of patients with CUP but robust evidence to support widespread use is lacking. Precision medicine has transformed treatment strategy in known tumour types; in CUP, however, there remains a clinical need for a better understanding of molecular characteristics to establish the potential role of novel or existing therapeutics. The emergence of liquid biopsies as a source of predictive and prognostic biomarkers within known tumour types is gaining rapid ground and this review explores the potential utility of liquid biopsies in CUP.

Circulating Tumor Cells: Overview and Opportunities in Cytology

Circulating tumor cells (CTCs) have long been assumed to be the substrate of cancer metastasis. However, only in recent years have we begun to leverage the potential of CTCs found in minimally invasive peripheral blood specimens to improve care for cancer patients. Currently, CTC enumeration is an accepted prognostic indicator for breast, prostate, and colorectal cancer; however, CTC enumeration remains largely a research tool. More recently, the focus has shifted to CTC characterization and isolation which holds great promise for predictive testing. This review summarizes the relevant clinical, biological, and technical background necessary for pathologists and cytopathologists to appreciate the potential of CTC techniques. A summary of relevant systematic reviews of CTCs for specific cancers is then presented, as well as potential applications to precision medicine. Finally, we suggest future applications of CTC technologies that can be easily incorporated in the pathology laboratory, with the recommendation that pathologists and particularly cytopathologists apply these technologies to small specimens in the era of "doing more with less."

Next-generation sequencing of circulating tumor DNA for detection of gene mutations in lung cancer: implications for precision treatment

Background

Lung cancer remains a major global health problem, which causes millions of deaths annually. Because the prognosis is mainly determined by the stage of lung cancer, precise early diagnosis is of great significance to improve the survival and prognosis. Circulating tumor DNA (ctDNA) has been recognized as a sensitive and specific biomarker for the detection of early- and late-stage lung cancer, and next-generation sequencing (NGS) of ctDNA has been accepted as a noninvasive tool for early identification and monitoring of cancer mutations. This study aimed to assess the value of NGS-based ctDNA analysis in detecting gene mutations in lung cancer patients.

Methods

A total of 101 subjects with pathological diagnosis of lung cancer were enrolled, and blood samples were collected. ctDNA samples were prepared and subjected to NGS assays.

Results

There were 31 cases harboring 40 gene mutations, and EGFR was the most frequently mutated gene (27.72%). In addition, there were seven cases with double mutations and one case with triple mutations, with EGFR p.T790M mutation exhibiting the highest frequency.

Conclusion

Our findings demonstrate that NGS of ctDNA is effective in detecting gene mutations in lung cancer patients, and may be used as a liquid biopsy for lung cancer, which facilitates the development of precision treatment regimens for lung cancer.

Dysregulation of Nrf2 in Hepatocellular Carcinoma: Role in Cancer Progression and Chemoresistance

The liver executes versatile functions and is the chief organ for metabolism of toxicants/xenobiotics. Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and the third foremost cause of cancer death worldwide. Oxidative stress is a key factor related with the development and progression of HCC. Nuclear factor erythroid 2 [NF-E2]-related factor 2 (Nrf2) is a cytosolic transcription factor, which regulates redox homeostasis by activating the expression of an array of antioxidant response element-dependent genes. Nrf2 displays conflicting roles in normal, healthy liver and HCC; in the former, Nrf2 offers beneficial effects, whereas in the latter it causes detrimental effects favouring the proliferation and survival of HCC. Sustained Nrf2 activation has been observed in HCC and facilitates its progression and aggressiveness. This review summarizes the role and mechanism(s) of action of Nrf2 dysregulation in HCC and therapeutic options that can be employed to modulate this transcription factor.

Autologous cell lines from circulating colon cancer cells captured from sequential liquid biopsies as model to study therapy-driven tumor changes

Circulating tumor cells (CTCs) are important clinical indicators for prognosis and treatment efficacy. However, CTC investigation is hampered by their low number, making the establishment of permanent CTC lines very challenging. We derived and characterized nine CTC lines using blood samples from a patient with metastatic colorectal cancer collected before and after chemotherapy and targeted therapy, and during cancer progression. These cell lines displayed an intermediate epithelial/mesenchymal phenotype, stem-cell like characteristics, angiogenesis potential, an osteomimetic signature and the capacity to escape from the immune system. Moreover, they showed changes in mRNA and protein expression (e.g., DEFA6, ABCB1 and GAL), whereas analysis of chromosomal copy number aberrations revealed no significant variation over time. These data indicate that although CTC lines derived from sequential blood samples during therapy have common traits, treatment-resistant CTC clones with distinct phenotypic characteristics are selected over time.

Microfluidic technologies in cell isolation and analysis for biomedical applications

Efficient platforms for cell isolation and analysis play an important role in applied and fundamental biomedical studies. As cells commonly have a size of around 10 microns, conventional handling approaches at a large scale are still challenged in precise control and efficient recognition of cells for further performance of isolation and analysis. Microfluidic technologies have become more prominent in highly efficient cell isolation for circulating tumor cells (CTCs) detection, single-cell analysis and stem cell separation, since microfabricated devices allow for the spatial and temporal control of complex biochemistries and geometries by matching cell morphology and hydrodynamic traps in a fluidic network, as well as enabling specific recognition with functional biomolecules in the microchannels. In addition, the fabrication of nano-interfaces in the microchannels has been increasingly emerging as a very powerful strategy for enhancing the capability of cell capture by improving cell-interface interactions. In this review, we focus on highlighting recent advances in microfluidic technologies for cell isolation and analysis. We also describe the general biomedical applications of microfluidic cell isolation and analysis, and finally make a prospective for future studies.

Techniques of using circulating tumor DNA as a liquid biopsy component in cancer management

Precision medicine in the clinical management of cancer may be achieved through the diagnostic platform called “liquid biopsy”. This method utilizes the detection of biomarkers in blood for prognostic and predictive purposes. One of the latest blood born markers under investigation in the field of liquid biopsy in cancer patients is circulating tumor DNA (ctDNA). ctDNA is released by tumor cells through different mechanisms and can therefore provide information about the genomic make-up of the tumor currently present in the patient. Through longitudinal ctDNA-based liquid biopsies, tumor dynamics may be monitored to predict and assess drug response and/or resistance. However, because ctDNA is highly fragmented and because its concentration can be extremely low in a high background of normal circulating DNA, screening for clinical relevant mutations is challenging. Although significant progress has been made in advancing the detection and analysis of ctDNA in the last few years, the current challenges include standardization and increasing current techniques to single molecule sensitivity in combination with perfect specificity. This review focuses on the potential role of ctDNA in the clinical management of cancer patients, the current technologies that are being employed, and the hurdles that still need to be taken to achieve ctDNA-based liquid biopsy towards precision medicine.

Associations between the cyclooxygenase-2 expression in circulating tumor cells and the clinicopathological features of patients with colorectal cancer

While previous studies have shown that the number of circulating tumor cells (CTCs) alone is not sufficient to reflect tumor progression and that cyclooxygenase-2 (COX-2) expression is correlated with colorectal cancer (CRC) metastasis, COX-2 expression status and its potential functions in CTCs of CRC patients are unknown. Here, epithelial-mesenchymal transition (EMT) phenotype-based subsets of CTCs and the COX-2 expression status in CTCs were identified and their potential clinical values were assessed in 91 CRC patients. CTCs were enumerated in peripheral blood and subsets of CTCs (epithelial [eCTCs], mesenchymal [mCTCs], and biophenotypic [bCTCs]) and the COX-2 expression status were determined using the RNA in situ hybridization method. CTCs were detected in 80.2% (73 of 91) patients. Neither the total CTC nor eCTC numbers were found to significantly associate with any of the clinicopathological features. However, the number of mCTCs was significantly associated with distance metastasis (P = 0.035) and had a trend of being associated with lymph node metastasis ( P = 0.055). Among the 73 patients enrolled for evaluating COX-2 expression, 52.5% (38 of 73) were found to express COX-2 in CTCs, and COX-2 expression in CTCs was not found to associate with the clinicopathological factors. However, COX-2 expression in mCTCs tended to have a higher rate in patients with metastasis compared with those without metastasis (72.0% vs 42.8%; P = 0.072). Furthermore, COX-2 expression and mCTC marker expression correlated positively ( R = 0.287; P = 0.017). Further studies are required to investigate the clinical value of the expression of COX-2 in mCTCs, especially in CRC patients with the advanced tumor stage and distant metastasis.

Application of liquid biopsy in bone and soft tissue sarcomas: Present and future

Bone and soft tissue sarcomas account for approximately 1% of adult solid malignancies and 20% of pediatric solid malignancies. Sarcomas are divided into more than 50 subtypes. Each subtype is highly heterogeneous and characterized by significant morphological and phenotypic variability. Currently, sarcoma characterization is based on tissue biopsies. However, primary and invasive tissue biopsies may not accurately reflect the current disease condition following treatment as is may cause marked changes to the tumor cells. Liquid biopsy offers an alternative minimally invasive approach to provide dynamic tumor information, allowing for the application of precision medicine in the treatment of sarcomas. Recently, there have been numerous blood-based tumor components identified by liquid biopsy in sarcomas, including circulating tumor cells, circulating cell-free nucleic acids, tumor-derived exosomes and metabolites in circulation. Here, we summarize the current evolving technologies and then elaborate on emerging novel concepts that may further propel the field of liquid biopsy in sarcomas. We address the applications in the context of our current knowledge about liquid biopsy in sarcomas and highlight the potential of translating these recent advances into the clinic for more effective management strategies for sarcoma patients.

Genetics and biology of prostate cancer

Despite the high long-term survival in localized prostate cancer, metastatic prostate cancer remains largely incurable even after intensive multimodal therapy. The lethality of advanced disease is driven by the lack of therapeutic regimens capable of generating durable responses in the setting of extreme tumor heterogeneity on the genetic and cell biological levels. Here, we review available prostate cancer model systems, the prostate cancer genome atlas, cellular and functional heterogeneity in the tumor microenvironment, tumor-intrinsic and tumor-extrinsic mechanisms underlying therapeutic resistance, and technological advances focused on disease detection and management. These advances, along with an improved understanding of the adaptive responses to conventional cancer therapies, anti-androgen therapy, and immunotherapy, are catalyzing development of more effective therapeutic strategies for advanced disease. In particular, knowledge of the heterotypic interactions between and coevolution of cancer and host cells in the tumor microenvironment has illuminated novel therapeutic combinations with a strong potential for more durable therapeutic responses and eventual cures for advanced disease. Improved disease management will also benefit from artificial intelligence-based expert decision support systems for proper standard of care, prognostic determinant biomarkers to minimize overtreatment of localized disease, and new standards of care accelerated by next-generation adaptive clinical trials.

Herbal management of hepatocellular carcinoma through cutting the pathways of the common risk factors

Hepatocellular carcinoma (HCC) is considered the most frequent tumor that associated with high mortality rate. Several risk factors contribute to the pathogenesis of HCC, such as chronic persistent infection with hepatitis C virus or hepatitis B virus, chronic untreated inflammation of liver with different etiology, oxidative stress and fatty liver disease. Several treatment protocols are used in the treatment of HCC but they also associated with diverse side effects. Many natural products are helpful in the co-treatment and prevention of HCC. Several mechanisms are involved in the action of these herbal products and their bioactive compounds in the prevention and co-treatment of HCC. They can inhibit the liver cancer development and progression in several ways as protecting against liver carcinogens, enhancing effects of chemotherapeutic drugs, inhibiting tumor cell growth and metastasis, and suppression of oxidative stress and chronic inflammation. In this review, we will discuss the utility of diverse natural products in the prevention and co-treatment of HCC, through its capturing of the common risk factors known to lead to HCC and shed the light on their possible mechanisms of action. Our theory assumes that shutting down the risk factor to cancer development pathways is a critical strategy in cancer prevention and management. We recommend the use of these plants side by side to recent chemical medications and after stopping these chemicals, as a maintenance therapy to avoid HCC progression and decrease its global incidence.

Epigenetics in ovarian cancer

Ovarian cancer is a disease with a poor prognosis and little progress has been made to improve treatment. It is now recognized that there are several histotypes of ovarian cancer, each with distinct epidemiologic and genomic characteristics. Cancer therapy is moving beyond classical chemotherapy to include epigenetic approaches. Epigenetics is the dynamic regulation of gene expression by DNA methylation and histone post translational modification in response to environmental cues. Improvement in technology to study DNA methylation has enabled a more agnostic approach and, with larger samples sets, has begun to unravel how epigenetics contributes to the etiology, response to chemotherapy and prognosis in of ovarian cancer. Investigations into histone modifications in ovarian cancer are more nascent. Much more is needed to be done to fully realize the potential that epigenetics holds for ovarian cancer clinical care.

The Clinical Landscape of Circulating Tumor DNA in Gastrointestinal Malignancies

Technologies for genomic analyses have revealed more details in cancer biology and have changed standard treatments for cancer, including the introduction of targeted gene-specific therapy. Currently, liquid biopsies are increasingly being utilized in clinical trials and research settings to analyze circulating tumor DNA (ctDNA) from peripheral blood. Several studies have shown the potential of ctDNA in the screening, prognostication, molecular profiling, and monitoring of gastrointestinal malignancies. Although limitations continue to exist in the use of ctDNA, such as method standardization, the sensitivity, concordance with tumor tissue, and regulatory issues, this field offers promising benefits for cancer treatment. A deeper understanding of tumor biology via ctDNA analyses and ctDNA-guided clinical trials will lead to the increasing use of ctDNA in clinical practice in the near future; this development will result in the improvement of outcomes among patients with gastrointestinal malignancies.

Circulating tumor DNA in blood: Future genomic biomarkers for cancer detection

Cancer is characterized by Darwinian evolution and is a primary cause of mortality and morbidity around the globe. Over the preceding decade, the treatment of cancer has been markedly improved by many targeted therapies, but these treatments have given birth to new challenges and issues. Clonal evolution and tumor heterogeneity present a significant challenge in designing cancer therapies. Fortunately, these restrictions have been overcome by technological advancements allowing us to track both genetic and epigenetic aberrations. Cell-free circulating tumor DNA (ctDNA) analysis, or "liquid biopsy" from a blood sample, provides the opportunity to track the genetic landscape of cancerous lesions. This review focuses on ctDNA analysis as a noninvasive method and versatile biomarker for cancer treatment and technological advancements for ctDNA analysis. This method may able to cope with all the challenges associated with previous cancer therapies and has the potential to monitor minimal residual disease, tumor burden, and therapy response and provide rapid detection of relapse. However, there are many challenges that still need to be addressed. Future prognosis, diagnosis, and analysis of ctDNA require reproducibility and accuracy of results, which are not possible without the validation and optimization of procedures. Integrated digital error suppression has thus far shown promise in the detection of ctDNA in cancer.

LncRNAs and EGFRvIII sequestered in TEPs enable blood-based NSCLC diagnosis

Background

Tissue biopsy-based cancer diagnosis has limitations because of the fact that tumor tissues are in constant evolution and extremely heterogeneous. The current study was aimed to examine whether tumor-educated blood platelets (TEPs) might be a potential all-in-one source for blood-based cancer diagnostics to overcome the limitations of conventional cancer biopsy.

Methods

In the present study, we evaluated the expression pattern of MAGI2 antisense RNA 3 (MAGI2-AS3) and ZNFX1 antisense RNA 1 (ZFAS1) in both plasma and platelets of 101 non-small-cell lung cancer (NSCLC) patients. Receiver operating characteristic (ROC) curve was generated to evaluate their diagnostic potential. In addition, epidermal growth factor receptor (EGFR) mutations were detected in DNA and RNA samples of platelets for companion diagnostics.

Results

Our results showed that the levels of MAGI2-AS3 and ZFAS1 in both plasma and platelets of NSCLC patients were significantly downregulated than those in healthy controls. A positive correlation of long noncoding RNA expression was observed between platelets and plasma (r=0.738 for MAGI2-AS3, r=0.751 for ZFAS1, respectively). By ROC analysis, we found that molecular interrogation of MAGI2-AS3 and ZFAS1 in TEPs and plasma can offer valuable diagnostic performance for NSCLC patients (area under the ROC curve [AUC]_MAGI2-AS3= 0.853/0.892, and AUC_ZFAS1=0.780/0.744 for diagnosing adenocarcinoma and squamous cell carcinoma cases from controls, respectively). Clinicopathologic characteristic analysis further revealed that MAGI2-AS3 level significantly correlated with tumor–node–metastasis (TNM) stage (p=0.001 in TEPs, p=0.003 in plasma), lymph-node metastasis (p=0.016 in TEPs, p=0.023 in plasma), and distant metastasis (p=0.045 in TEPs, p=0.045 in plasma), while ZFAS1 level was only correlated with TNM stage (p=0.005 in TEPs, p=0.044 in plasma). Furthermore, EGFRvIII RNA existed in both TEPs and plasma, but EGFR intracellular mutations cannot be detected in DNA of TEPs isolated from NSCLC.

Conclusion

Our data suggested that TEP is a promising source for NSCLC diagnosis and companion diagnostics.

Characterization and diagnostic application of genomic NPM-ALK fusion sequences in anaplastic large-cell lymphoma

Nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion genes resulting from the translocation t(2;5)(p23;q35) are present in almost 90% of childhood ALK-positive anaplastic large-cell lymphomas (ALCL). Detection and quantification of minimal disseminated disease (MDD) by measuring NPM-ALK fusion transcript levels in the blood provide independent prognostic parameters. Characterization of the genomic breakpoints provides insights into the pathogenesis of the translocation and allows for DNA-based minimal disease monitoring.

We designed a nested multiplex PCR assay for identification and characterization of genomic NPM-ALK fusion sequences in 45 pediatric ALCL-patients, and used the sequences for quantitative MDD monitoring. Breakpoint analysis indicates the involvement of inaccurate non-homologous end joining repair mechanisms in the formation of NPM-ALK fusions. Parallel quantification of RNA and DNA levels in the cellular fraction of 45 blood samples from eight patients with NPM-ALK-positive ALCL correlated, as did cell-free circulating NPM-ALK DNA copies in the plasma fraction of 37 blood samples. With genomic NPM-ALK fusion sequence quantification, plasma samples of ALCL patients become an additional source for MRD-assessment. Parallel quantification of NPM-ALK transcripts and fusion genes in ALCL cell lines treated with the ALK kinase inhibitor crizotinib illustrates the potential value of supplementary DNA-based quantification in particular clinical settings.

Chemical modification of halloysite nanotubes for controlled loading and release

Clay minerals have been used for medical purposes from ancient times. Among them, the halloysite nanotube, an aluminosilicate of the kaolin group, is an emerging nanomaterial which possesses peculiar chemical characteristics. By means of suitable modifications, such as supramolecular functionalization or covalent modifications, it is possible to obtain novel nanomaterials with tunable properties for several applications. In this context the covalent grafting of suitable organic moieties on the external surface or in the halloysite lumen has been exploited to improve the loading and release of several biologically active molecules. The resulting hybrid nanomaterials have been applied as drug carrier and delivery systems, as fillers for hydrogels, in tissue regeneration and in the gene delivery field. Furthermore the loading and release of specific molecules have been also investigated for environmental purposes. This review summarizes the main developments in the halloysite modifications in the last 20 years with a particular attention to the development in the past two years.

Circulating tumor DNA and liquid biopsy: opportunities, challenges, and recent advances in detection technologies

Cell-free DNA (cfDNA) refers to short fragments of acellular nucleic acids detectable in almost all body fluids, including blood, and is involved in various physiological and pathological phenomena such as immunity, coagulation, aging, and cancer. In cancer patients, a fraction of hematogenous cfDNA originates from tumors, termed circulating tumor DNA (ctDNA), and may carry the same mutations and genetic alterations as those of a primary tumor. Thus, ctDNA potentially provides an opportunity for noninvasive assessment of cancer. Recent advances in ctDNA analysis methods will potentially lead to the development of a liquid biopsy tool for the diagnosis, prognosis, therapy response monitoring, and tracking the rise of new mutant sub-clones in cancer patients. Over the past few decades, cancer-specific mutations in ctDNA have been detected using a variety of untargeted methods such as digital karyotyping, personalized analysis of rearranged ends (PARE), whole-genome sequencing of ctDNA, and targeted approaches such as conventional and digital PCR-based methods and deep sequencing-based technologies. More recently, several chip-based electrochemical sensors have been developed for the analysis of ctDNA in patient samples. This paper aims to comprehensively review the diagnostic, prognostic, and predictive potential of ctDNA as a minimally invasive liquid biopsy for cancer patients. We also present an overview of current advances in the analytical sensitivity and accuracy of ctDNA analysis methods as well as biological and technical challenges, which need to be resolved for the integration of ctDNA analysis into routine clinical practice.

Circulating tumor cell isolation, culture, and downstream molecular analysis

Circulating tumor cells (CTCs) are a major contributor of cancer metastases and hold a promising prognostic significance in cancer detection. Performing functional and molecular characterization of CTCs provides an in-depth knowledge about this lethal disease. Researchers are making efforts to design devices and develop assays for enumeration of CTCs with a high capture and detection efficiency from whole blood of cancer patients. The existing and on-going research on CTC isolation methods has revealed cell characteristics which are helpful in cancer monitoring and designing of targeted cancer treatments. In this review paper, a brief summary of existing CTC isolation methods is presented. We also discuss methods of detaching CTC from functionalized surfaces (functional assays/devices) and their further use for ex-vivo culturing that aid in studies regarding molecular properties that encourage metastatic seeding. In the clinical applications section, we discuss a number of cases that CTCs can play a key role for monitoring metastases, drug treatment response, and heterogeneity profiling regarding biomarkers and gene expression studies that bring treatment design further towards personalized medicine.

High-sensitivity assay for monitoring ESR1 mutations in circulating cell-free DNA of breast cancer patients receiving endocrine therapy

Approximately 70% of breast cancers (BCs) express estrogen receptor alpha (ERα) and are treated with endocrine therapy. However, the effectiveness of this therapy is limited by innate or acquired resistance in approximately one-third of patients. Activating mutations in the ESR1 gene that encodes ERα promote critical resistance mechanisms. Here, we developed a high sensitivity approach based on enhanced-ice-COLD-PCR for detecting ESR1 mutations. The method produced an enrichment up to 100-fold and allowed the unambiguous detection of ESR1 mutations even when they consisted of only 0.01% of the total ESR1 allelic fraction. After COLD-PCR enrichment, methods based on next-generation sequencing or droplet-digital PCR were employed to detect and quantify ESR1 mutations. We applied the method to detect ESR1 mutations in circulating free DNA from the plasma of 56 patients with metastatic ER-positive BC. Fifteen of these patients were found to have ESR1 mutations at codons 536-538. This study demonstrates the utility of the enhanced-ice-COLD-PCR approach for simplifying and improving the detection of ESR1 tumor mutations in liquid biopsies. Because of its high sensitivity, the approach may potentially be applicable to patients with non-metastatic disease.

Dynamic change of PD-L1 expression on circulating tumor cells in advanced solid tumor patients undergoing PD-1 blockade therapy

Background: Tumor PD-L1 levels have predictive value in PD-1/PD-L1 checkpoint blockade therapies, yet biopsies can only provide baseline information. Whether PD-L1 expression on circulating tumor cells (CTCs) could serve as an alternative biomarker is of great interest. Design: We established an immunofluorescence assay for semi-quantitative assessment of the PD-L1 expression levels on CTCs with four categories (PD-L1negative, PD-L1low, PD-L1medium and PD-L1high). 35 patients with different advanced gastrointestinal tumors were enrolled in a phase 1 trial of a PD-1 inhibitor, IBI308. The CTC numeration and the PD-L1 expression levels were analyzed. Results: Prior the treatment of IBI308, 97% (34/35) patients had CTCs, ranging from1 to 70 (median 7). 74% (26/35) had PD-L1positive CTCs, and 60% (21/35) had at least one PD-L1high CTCs. The disease control (DC) rate in PD-L1high patients (48%) is much higher than the others (14%). The group with at least 20% abundance of PD-L1high CTCs had even higher DC rate of 64% (9/14), with only 14% DC rate for the rest (3/21). We also observed that the count changes of total CTC, PD-L1postive CTC and PD-L1high CTC correlate quite well with disease outcome (P<0.001, P = 0.002 and 0.007, respectively). In addition, the abundance of PD-L1high CTCs at baseline had predicative significance for progression free survival (PFS). Conclusions: We revealed that the abundance of PD-L1high CTCs at baseline might serve as a predictor to screen patients for PD-1/PD-L1 blockade therapies and measuring the dynamic changes of CTC could indicate the therapeutic response at early time.

Dynamic network biomarker indicates pulmonary metastasis at the tipping point of hepatocellular carcinoma

Developing predictive biomarkers that can detect the tipping point before metastasis of hepatocellular carcinoma (HCC), is critical to prevent further irreversible deterioration. To discover such early-warning signals or biomarkers of pulmonary metastasis in HCC, we analyse time-series gene expression data in spontaneous pulmonary metastasis mice HCCLM3-RFP model with our dynamic network biomarker (DNB) method, and identify CALML3 as a core DNB member. All experimental results of gain-of-function and loss-of-function studies show that CALML3 could indicate metastasis initiation and act as a suppressor of metastasis. We also reveal the biological role of CALML3 in metastasis initiation at a network level, including proximal regulation and cascading influences in dysfunctional pathways. Our further experiments and clinical samples show that DNB with CALML3 reduced pulmonary metastasis in liver cancer. Actually, loss of CALML3 predicts shorter overall and relapse-free survival in postoperative HCC patients, thus providing a prognostic biomarker and therapy target in HCC.

A dual biomarker detection platform for quantitating circulating tumor DNA (ctDNA)

Circulating tumor DNA (ctDNA), which includes DNA mutations, epigenetic alterations and other forms of tumor-specific abnormalities, is a promising “real-time” biomarker for noninvasive cancer assessment. Tumor DNA is of great value in the process of cancer treatment, including diagnostic and prognostic information before, during treatment and at progression. Here we introduce a peptide nucleic acids probe-gold nanoparticles (PNA-AuNPs) and lead phosphate apoferritin (LPA)-based dual biomarker detection platform, which could be used in a DNA biosensor to quantify ctDNA by detection of tumor-specific mutations and methylation of PIK3CA gene. On the one hand, PNA probe and anti-5-Methylcytosine monoclonal antibody (anti-5-mC) were used to recognize the different parts of ctDNA, forming a sandwich-structure on a screen-printed electrode (SPE) surface. On the other hand, AuNPs and LPA were introduced to construct the biosensor for double signal amplification. Square-wave voltammetry (SWV) was used to monitor the electrochemical signal of lead ions released from apoferritin. The proposed DNA biosensor yielded a linear current response to ctDNA concentrations over a broad range of 50-10000 fM with a detection limit of 10 fM. It also successfully detected ctDNA collected from cancer patient serum. Therefore, we anticipate this new platform opens up an approach to detect and monitor diverse malignancies, facilitating personalized cancer therapy.

Nanotechnology-Based Strategies for Early Cancer Diagnosis Using Circulating Tumor Cells as a Liquid Biopsy

Circulating tumor cells (CTCs) are cancer cells that shed from a primary tumor and circulate in the bloodstream. As a form of “tumor liquid biopsy”, CTCs provide important information for the mechanistic investigation of cancer metastasis and the measurement of tumor genotype evolution during treatment and disease progression. However, the extremely low abundance of CTCs in the peripheral blood and the heterogeneity of CTCs make their isolation and characterization major technological challenges. Recently, nanotechnologies have been developed for sensitive CTC detection; such technologies will enable better cell and molecular characterization and open up a wide range of clinical applications, including early disease detection and evaluation of treatment response and disease progression. In this review, we summarize the nanotechnology-based strategies for CTC isolation, including representative nanomaterials (such as magnetic nanoparticles, gold nanoparticles, silicon nanopillars, nanowires, nanopillars, carbon nanotubes, dendrimers, quantum dots, and graphene oxide) and microfluidic chip technologies that incorporate nanoroughened surfaces and discuss their key challenges and perspectives in CTC downstream analyses, such as protein expression and genetic mutations that may reflect tumor aggressiveness and patient outcome.

Diagnostic value of circulating cell-free DNA levels for hepatocellular carcinoma

OBJECTIVES

Circulating cell-free DNA (cfDNA) is a potential biomarker for tumor diagnosis. Hepatocyte damage is a characteristic component of the pathobiology of hepatocellular carcinoma (HCC), which would be expected to result in substantial leakage of cfDNA into the circulation. However, the diagnostic value of cfDNA levels for HCC remains unclear.

METHODS

Plasma samples were collected from 24 HCC patients and 62 hepatitis B virus-related liver fibrosis patients. Plasma cfDNA levels were quantified by Qubit method.

RESULTS

Plasma cfDNA levels were associated with the degree of liver inflammation, body mass index, and alpha-fetoprotein (AFP) level, but were not associated with fibrosis stages. Plasma cfDNA levels were significantly higher in HCC patients than in non-HCC patients. Multivariate analysis revealed that age and cfDNA, rather than AFP, were independent predictors of HCC. The HCC index, a combination model including age, cfDNA, and AFP, had an area of 0.98 (95% confidence interval 0.92-1.00) under the receiver operating characteristics curve for the diagnosis of HCC at the cut-off value of 0.61, with 87.0% sensitivity and 100% specificity. The diagnostic power of the HCC index was superior to that of cfDNA alone and AFP alone.

CONCLUSIONS

These results suggest that the combination of cfDNA with age and AFP could improve the diagnostic performance for HCC.

High-throughput full-length single-cell mRNA-seq of rare cells

Single-cell characterization techniques, such as mRNA-seq, have been applied to a diverse range of applications in cancer biology, yielding great insight into mechanisms leading to therapy resistance and tumor clonality. While single-cell techniques can yield a wealth of information, a common bottleneck is the lack of throughput, with many current processing methods being limited to the analysis of small volumes of single cell suspensions with cell densities on the order of 10⁷ per mL. In this work, we present a high-throughput full-length mRNA-seq protocol incorporating a magnetic sifter and magnetic nanoparticle-antibody conjugates for rare cell enrichment, and Smart-seq2 chemistry for sequencing. We evaluate the efficiency and quality of this protocol with a simulated circulating tumor cell system, whereby non-small-cell lung cancer cell lines (NCI-H1650 and NCI-H1975) are spiked into whole blood, before being enriched for single-cell mRNA-seq by EpCAM-functionalized magnetic nanoparticles and the magnetic sifter. We obtain high efficiency (> 90%) capture and release of these simulated rare cells via the magnetic sifter, with reproducible transcriptome data. In addition, while mRNA-seq data is typically only used for gene expression analysis of transcriptomic data, we demonstrate the use of full-length mRNA-seq chemistries like Smart-seq2 to facilitate variant analysis of expressed genes. This enables the use of mRNA-seq data for differentiating cells in a heterogeneous population by both their phenotypic and variant profile. In a simulated heterogeneous mixture of circulating tumor cells in whole blood, we utilize this high-throughput protocol to differentiate these heterogeneous cells by both their phenotype (lung cancer versus white blood cells), and mutational profile (H1650 versus H1975 cells), in a single sequencing run. This high-throughput method can help facilitate single-cell analysis of rare cell populations, such as circulating tumor or endothelial cells, with demonstrably high-quality transcriptomic data.

Liquid Biopsy: From Basic Research to Clinical Practice

Liquid biopsy refers to the molecular analysis in biological fluids of nucleic acids, subcellular structures, especially exosomes, and, in the context of cancer, circulating tumor cells. In the last 10 years, there has been an intensive research in liquid biopsy to achieve a less invasive and more precise personalized medicine. Molecular assessment of these circulating biomarkers can complement or even surrogate tissue biopsy. Because of this research, liquid biopsy has been introduced in clinical practice, especially in oncology, prenatal screening, and transplantation. Here we review the biology, methodological approaches, and clinical applications of the main biomarkers involved in liquid biopsy.

Circulating biomarkers in osteosarcoma: new translational tools for diagnosis and treatment

Osteosarcoma (OS) is a rare primary malignant bone tumour arising from primitive bone-forming mesenchymal cells, with high incidence in children and young adults, accounting for approximately 60% of all malignant bone tumours. Currently, long-term disease-free survival can be achieved by surgical treatment plus chemotherapy in approximately 60% of patients with localized extremity disease, and in 20-30% of patients with metastatic lung or bone disease. Diagnosis of primary lesions and recurrences is achieved by using radiological investigations and standard tissue biopsy, the latter being costly, painful and hardly repeatable for patients. Therefore, despite some recent advances, novel biomarkers for OS diagnosis, prediction of response to therapy, disease progression and chemoresistance, are urgently needed. Biological fluids such as blood represent a rich source of non-invasive cancer biomarkers, which allow to understand what is really happening inside the tumour, either at diagnosis or during disease progression. In this regard, liquid biopsy potentially represents an alternative and non-invasive method to detect tumour onset, progression and response to therapy. In this review, we will summarize the state of the art in this novel area, illustrating recent studies on OS. Although the data reported in literature seem preliminary, liquid biopsy represents a promising tool with the potential to be rapidly translated in the clinical practice.

Circulating Cell-free DNA for Metastatic Cervical Cancer Detection, Genotyping, and Monitoring

Purpose: Circulating cell-free (ccf) human papillomavirus (HPV) DNA may serve as a unique tumor marker for HPV-associated malignancies, including cervical cancer. We developed a method to genotype and quantify circulating HPV DNA in patients with HPV16- or HPV18-positive metastatic cervical cancer for potential disease monitoring and treatment-related decision making.Experimental Design: In this retrospective study, HPV ccfDNA was measured in serum samples from 19 metastatic cervical cancer patients by duplex digital droplet PCR (ddPCR). Nine patients had received tumor-infiltrating lymphocyte (TIL) immunotherapy. ccfDNA data were aligned with the tumor HPV genotype, drug treatment, and clinical outcome.Results: In blinded tests, HPV ccfDNA was detected in 19 of 19 (100%) patients with HPV-positive metastatic cervical cancer but not in any of the 45 healthy blood donors. The HPV genotype harbored in the patients' tumors was correctly identified in 87 of 87 (100%) sequential patient serum samples from 9 patients who received TIL immunotherapy. In three patients who experienced objective cancer regression after TIL treatment, a transient HPV ccfDNA peak was detected 2-3 days after TIL infusion. Furthermore, persistent clearance of HPV ccfDNA was only observed in two patients who experienced complete response (CR) after TIL immunotherapy.Conclusions: HPV ccfDNA represents a promising tumor marker for noninvasive HPV genotyping and may be used in selecting patients for HPV type-specific T-cell-based immunotherapies. It may also have value in detecting antitumor activity of therapeutic agents and in the long-term follow-up of cervical cancer patients in remission. Clin Cancer Res; 23(22); 6856-62. ©2017 AACR.

Identification of Mutations in Cell-Free Circulating Tumor DNA in Adrenocortical Carcinoma: A Case Series

CONTEXT

The disease course of adrenocortical carcinoma (ACC) patients is heterogeneous. A marker for prognosis and treatment response would facilitate choices for diagnosis and therapy. In other cancer types, circulating cell-free tumor DNA predicted tumor dynamics.

CASE DESCRIPTIONS

The present pilot study included six patients. Next-generation sequencing (NGS) showed mutations in three ACC cases. From these patients, blood was drawn before (1 to 2 weeks) and after surgery and cell-free circulating DNA (cfDNA) was isolated. Tumor-specific mutations were found in the cfDNA of one of the three patients, with metastasized ACC at diagnosis. NGS of the tumor showed an NRAS mutation (c.182A>G:p.Q61R) in 78%, a TP53 mutation (c.856G>A:p.E286K) in 60%, and a TERT gene mutation (1295250C>T) in 28% of the reads. The preoperative cfDNA showed the same mutations at a frequency of 64%, 32%, and 2%, respectively. The postoperative cfDNA showed the same mutations but at lower frequencies (52%, 16%, and 3%, respectively). The patient was postoperatively treated with mitotane and chemotherapy. No mutations were detected in the corresponding leukocyte DNA or in the cfDNA from the two other patients.

CONCLUSIONS

To the best of our knowledge, we report for the first time mutations occurring at high levels in cfDNA collected before and after surgery from one of three patients, after previous identification in the tumor. However, in the cfDNA from two patients with known mutations, we were unable to reliably detect mutations in the cfDNA. Our results indicate that mutation detection in cfDNA can vary among ACC patients, and other approaches might be required to detect the tumor response and monitor progressive disease.