Detection of melanoma cells in peripheral blood by means of reverse transcriptase and polymerase chain reaction

Laser-Induced Minimization of Circulating Tumor Cells to Suppress Tumor Metastasis

Circulating tumor cells (CTCs) are key indicators of tumor metastasis. Effective clearance of CTCs can reduce the probability of metastasis. We designed a system for the real-time dynamic monitoring and clearance of CTCs, capable of monitoring and clearing CTCs in the living circulatory system. Experimental results showed that pulsed laser treatment significantly affects the clearance of melanoma CTCs. Through in vivo imaging of small animals and survival analysis of mice, we observed that CTC clearance could reduce the size of distant metastatic lesions and prolong the lifespan of the mice. Additionally, we set up a hemolysis experiment to demonstrate that the laser energy used does not cause damage to red blood cells. This study is based on the physical and mechanical destruction of CTCs, meaning there is no issue of drug resistance. This provides a novel approach and technical means for suppressing tumor metastasis and extending the lifespan of patients in clinical settings.

A Miniaturized In Vivo Fluorescence Microscopy Method for Monitoring Circulating Tumor Cells in Freely Moving Animals

Metastasis is the leading cause of death in tumor patients, with circulating tumor cells (CTCs) serving as key biomarkers for tumor progression, metastasis, and recurrence. CTC quantity is closely linked to tumor dynamics, which are influenced by biological rhythms. Studying CTC distribution under various physiological conditions provides insights into metastasis mechanisms. However, due to the low abundance of CTCs, detection accuracy is limited, especially with small blood samples, making continuous data collection challenging. To address this, we developed a dual-channel miniaturized in vivo fluorescence microscopy system for real-time monitoring of CTCs in experimental animals. This system, which can be fixed to the head or back, enables dynamic, quantitative analysis of CTCs in the circulatory system. It offers a valuable tool for investigating tumor metastasis rhythms, drug evaluation, and prognostic assessment in freely moving animals, advancing research in metastasis mechanisms and cancer treatment.

The Phenotypical Characterization of Dual-Nature Hybrid Cells in Uveal Melanoma

BACKGROUND

Metastasis, occurring years after primary diagnosis, represents a poor prognosis in uveal melanoma (UM)-affected individuals. The nature of cells involved in this process is under debate. Circulating hybrid cells that have combined tumor and immune cell features found in blood were predictive of metastasis and may correspond to dual-nature cells (DNC) in the primary tumor. Herein, we sought to determine the presence of DNCs in primary UM tumors, the cell types involved in their genesis, and their ability to be formed in vitro.

METHODS

UM lesions (n = 38) were immunolabeled with HMB45 in combination with immune-cell-specific antibodies. In parallel, we co-cultured UM cells and peripheral blood mononuclear cells (PBMCs) to analyze DNC formation.

RESULTS

HMB45+/CD45+ DNCs were present in 90% (26/29) of the tumors, HMB45+/CD8+ DNCs were present in 93% (26/28), and HMB45+/CD68+ DNCs were present in 71% (17/24). DNCs formed with CD8+ and CD68+ cells were positively correlated to the infiltration of their respective immune cells. Notably, UM cells were prone to hybridize with PBMCs in vitro.

CONCLUSIONS

This phenotypical characterization of DNCs in UM demonstrates that CD8+ T-cells and macrophages are capable of DNC formation, and they are important for better understanding metastatic dissemination, thus paving the path towards novel therapeutic avenues.

TUMOR MARKERS EXPRESSION LEVELS IN GASTRIC CANCER PATIENT'S PERIPHERAL BLOOD BY RT-PCR ASSESSMENT

BACKGROUND

Hematological recurrence is the second most frequent cause of failure in the treatment of gastric cancer. The detection of circulating tumor markers in peripheral blood by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) method may be a useful tool to predict recurrence and determine the patient's prognosis. However, no consensus has been reached regarding the association between the tumor markers level in peripheral blood and its impact on patient survival.

AIMS

To evaluate the expression of the circulating tumor markers CK20 and MUC1 in peripheral blood samples from patients with gastric cancer by qRT-PCR, and to verify the association of their expression levels with clinicopathological characteristics and survival.

METHODS

A total of 31 patients with gastric adenocarcinoma were prospectively included in this study. CK20 and MUC1 expression levels were analyzed from peripheral blood by the qRT-PCR technique.

RESULTS

There was no statistically significant (p>0.05) association between CK20 expression levels and clinical, pathological, and surgical features. Higher MUC1 expression levels were associated with female patients (p=0.01). There was a correlation between both gene levels (R=0.81, p<0.001), and CK20 level and tumor size (R=0.39, p=0.034).

CONCLUSIONS

CK20 and MUC1 expression levels could be assessed by qRT-PCR from total peripheral blood samples of patients with gastric cancer. CK20 levels were correlated to MUC1 levels as well as to tumor size. There was no difference in disease-free survival and overall survival regarding both genetic markers expression in this series.

An electrochemical biosensor based on network-like DNA nanoprobes for detection of mesenchymal circulating tumor cells

The identification and detection of mesenchymal circulating tumor cells （mCTCs） is important for early warning of tumor metastasis. The majority of conventional detection methods for CTCs rely on the recognition of epithelial biomarkers, which is technically challenging for detecting CTCs with epithelial-mesenchymal transition (EMT)-induced phenotypic alteration. In this work, we have constructed a label-free biosensor for sensitive electrochemical assay of mCTCs. In our design, the capture probe can recognize the vimentin overexpressed on the surface of mCTCs with high specificity. Meantime, the network-like DNA nanoprobes with multiple G-quadruplex/hemin complexes and multiple cholesterol molecules can be grafted to the cell surface based on the high affinity between cholesterol molecules and cell membrane. Owing to the mimic horseradish peroxidase of G-quadruplex/hemin complexes, strong electrochemical responses will be obtained for sensitive quantification of mCTCs with a detection limit of 8 cell mL-1. Moreover, the biosensor can effectively overcome the interference of vimentin negative cells or secretory vimentin, and realize the recovery tests in whole blood with high accuracy, thereby may further promoting the diagnosis and personalized treatment of cancer in clinic.

New Perspectives on the Importance of Cell-Free DNA Biology

Body fluids are constantly replenished with a population of genetically diverse cell-free DNA (cfDNA) fragments, representing a vast reservoir of information reflecting real-time changes in the host and metagenome. As many body fluids can be collected non-invasively in a one-off and serial fashion, this reservoir can be tapped to develop assays for the diagnosis, prognosis, and monitoring of wide-ranging pathologies, such as solid tumors, fetal genetic abnormalities, rejected organ transplants, infections, and potentially many others. The translation of cfDNA research into useful clinical tests is gaining momentum, with recent progress being driven by rapidly evolving preanalytical and analytical procedures, integrated bioinformatics, and machine learning algorithms. Yet, despite these spectacular advances, cfDNA remains a very challenging analyte due to its immense heterogeneity and fluctuation in vivo. It is increasingly recognized that high-fidelity reconstruction of the information stored in cfDNA, and in turn the development of tests that are fit for clinical roll-out, requires a much deeper understanding of both the physico-chemical features of cfDNA and the biological, physiological, lifestyle, and environmental factors that modulate it. This is a daunting task, but with significant upsides. In this review we showed how expanded knowledge on cfDNA biology and faithful reverse-engineering of cfDNA samples promises to (i) augment the sensitivity and specificity of existing cfDNA assays; (ii) expand the repertoire of disease-specific cfDNA markers, thereby leading to the development of increasingly powerful assays; (iii) reshape personal molecular medicine; and (iv) have an unprecedented impact on genetics research.

Do Extracellular RNAs Provide Insight into Uveal Melanoma Biology?

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults, showing a high mortality due to metastasis. Although it is considered a rare disease, a growing number of papers have reported altered levels of RNAs (i.e., coding and non-coding RNAs) in cancerous tissues and biological fluids from UM patients. The presence of circulating RNAs, whose dysregulation is associated with UM, paved the way to the possibility of exploiting it for diagnostic and prognostic purposes. However, the biological meaning and the origin of such RNAs in blood and ocular fluids of UM patients remain unexplored. In this review, we report the state of the art of circulating RNAs in UM and debate whether the amount and types of RNAs measured in bodily fluids mirror the RNA alterations from source cancer cells. Based on literature data, extracellular RNAs in UM patients do not represent, with rare exceptions, a snapshot of RNA dysregulations occurring in cancerous tissues, but rather the complex and heterogeneous outcome of a systemic dysfunction, including immune system activity, that modifies the mechanisms of RNA delivery from several cell types.

Liquid Biopsy in Melanoma: Significance in Diagnostics, Prediction and Treatment Monitoring

Liquid biopsy is a common term referring to circulating tumor cells and other biomarkers, such as circulating tumor DNA (ctDNA) or extracellular vesicles. Liquid biopsy presents a range of clinical advantages, such as the low invasiveness of the blood sample collection and continuous control of the tumor progression. In addition, this approach enables the mechanisms of drug resistance to be determined in various methods of cancer treatment, including immunotherapy. However, in the case of melanoma, the application of liquid biopsy in patient stratification and therapy needs further investigation. This review attempts to collect all of the relevant and recent information about circulating melanoma cells (CMCs) related to the context of malignant melanoma and immunotherapy. Furthermore, the biology of liquid biopsy analytes, including CMCs, ctDNA, mRNA and exosomes, as well as techniques for their detection and isolation, are also described. The available data support the notion that thoughtful selection of biomarkers and technologies for their detection can contribute to the development of precision medicine by increasing the efficacy of cancer diagnostics and treatment.

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

Tyrosinase (TYR, E.C. 1.14.18.1), a critical enzyme participating in melanogenesis, catalyzes the first two steps in melanin biosynthesis including the ortho-hydroxylation of L-tyrosine and the oxidation of L-DOPA. Previous pharmacological investigations have revealed that an abnormal level of TYR is tightly associated with various dermatoses, including albinism, age spots, and malignant melanoma. TYR inhibitors can partially block the formation of pigment, which are always used for improving skin tone and treating dermatoses. The practical and reliable assays for monitoring TYR activity levels are very useful for both disease diagnosis and drug discovery. This review comprehensively summarizes structural and enzymatic characteristics, catalytic mechanism and substrate preference of TYR, as well as the recent advances in biochemical assays for sensing TYR activity and their biomedical applications. The design strategies of various TYR substrates, alongside with several lists of all reported biochemical assays for sensing TYR including analytical conditions and kinetic parameters, are presented for the first time. Additionally, the biomedical applications and future perspectives of these optical assays are also highlighted. The information and knowledge presented in this review offer a group of practical and reliable assays and imaging tools for sensing TYR activities in complex biological systems, which strongly facilitates high-throughput screening TYR inhibitors and further investigations on the relevance of TYR to human diseases.

Unraveling the Wide Spectrum of Melanoma Biomarkers

The use of biomarkers in medicine has become essential in clinical practice in order to help with diagnosis, prognostication and prediction of treatment response. Since Alexander Breslow’s original report on “melanoma and prognostic values of thickness”, providing the first biomarker for melanoma, many promising new biomarkers have followed. These include serum markers, such as lactate dehydrogenase and S100 calcium-binding protein B. However, as our understanding of the DNA mutational profile progresses, new gene targets and proteins have been identified. These include point mutations, such as mutations of the BRAF gene and tumour suppressor gene tP53. At present, only a small number of the available biomarkers are being utilised, but this may soon change as more studies are published. The aim of this article is to provide a comprehensive review of melanoma biomarkers and their utility for current and, potentially, future clinical practice.

Circulating Plasma Tumor DNA Is Superior to Plasma Tumor RNA Detection in Ewing Sarcoma Patients: ptDNA and ptRNA in Ewing Sarcoma

The detection of tumor-specific nucleic acids from blood increasingly is being used as a method of liquid biopsy and minimal residual disease detection. However, achieving high sensitivity and high specificity remains a challenge. Here, we perform a direct comparison of two droplet digital PCR (ddPCR)-based detection methods, circulating plasma tumor RNA and circulating plasma tumor DNA (ptDNA), in blood samples from newly diagnosed Ewing sarcoma patients. First, we developed three specific ddPCR-based assays to detect EWS-FLI1 or EWS-ERG fusion transcripts, which naturally showed superior sensitivity to DNA detection on in vitro control samples. Next, we identified the patient-specific EWS-FLI1 or EWS-ERG breakpoint from five patient tumor samples and designed ddPCR-based, patient-specific ptDNA assays for each patient. These patient-specific assays show that although plasma tumor RNA can be detected in select newly diagnosed patients, positive results are low and statistically unreliable compared with ptDNA assays, which reproducibly detect robust positive results across most patients. Furthermore, the unique disease biology of Ewing sarcoma enabled us to show that most cell-free RNA is not tumor-derived, although cell-free-DNA burden is affected strongly by tumor-derived DNA burden. Here, we conclude that, even with optimized highly sensitive and specific assays, tumor DNA detection is superior to RNA detection in Ewing sarcoma patients.

Circulating RNA biomarkers in diffuse large B-cell lymphoma: a systematic review

Diffuse large B-cell lymphoma (DLBCL) is the most common histological subtype of non-Hodgkin's lymphomas (NHL). DLBCL is an aggressive malignancy that displays a great heterogeneity in terms of morphology, genetics and biological behavior. While a sustained complete remission is obtained in the majority of patients with standard immunochemotherapy, patients with refractory of relapsed disease after first-line treatment have a poor prognosis. This patient group represents an important unmet need in lymphoma treatment. In recent years, improved understanding of the underlying molecular pathogenesis had led to new classification and prognostication tools, including the development of cell-free biomarkers in liquid biopsies. Although the majority of studies have focused on the use of cell-free fragments of DNA (cfDNA), there has been an increased interest in circulating-free coding and non-coding RNA, including messenger RNA (mRNA), microRNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA), as well as RNA encapsulated in extracellular vesicles or tumor-educated platelets (TEPs). We performed a systematic search in PubMed to identify articles that evaluated circulating RNA as diagnostic, subtype, treatment response or prognostic biomarkers in a human DLBCL population. A total of 35 articles met the inclusion criteria. The aim of this systematic review is to present the current understanding of circulating RNA molecules as biomarker in DLBCL and to discuss their future potential.

Liquid biopsy in ovarian cancer: Catching the silent killer before it strikes

Epithelial ovarian cancer (EOC) is the most lethal gynaecological malignancy in the western world. The majority of women presenting with the disease are asymptomatic and it has been dubbed the "silent killer". To date there is no effective minimally invasive method of stratifying those with the disease or screening for the disease in the general population. Recent molecular and pathological discoveries, along with the advancement of scientific technology, means there is a real possibility of having disease-specific liquid biopsies available within the clinical environment in the near future. In this review we discuss these discoveries, particularly in relation to the most common and aggressive form of EOC, and their role in making this possibility a reality.

Past, present, and future perspectives of pulmonary metastasectomy for patients with advanced colorectal cancer

Over a half-century has passed since Thomford et al. proposed the selection criteria for pulmonary metastasectomy, and several prognostic factors have been identified. Although screening modalities and operations have changed dramatically, the important concepts of the selection criteria remain unchanged. Recent improvements in the survival outcomes of colorectal cancer patients undergoing pulmonary metastasectomy may be the result of strict adherence to the selection criteria for oligometastatic lung tumors, which can mimic local disease. Pulmonary metastasectomy has become an important option for selected patients with oligometastasis, based mainly on a large amount of retrospective data, but its effect on survival remains unclear. Curable pulmonary metastasis might be regarded as a "semi-local disease" under the spontaneous control of an acquired alteration in host immune status. The current practice of pulmonary metastasectomy for colorectal cancer focuses on selecting the most appropriate operation for selected patients. However, in the rapidly evolving era of immunotherapy, treatment-naïve patients for whom surgery is not suitable might be pre-conditioned by immunotherapy so that they may be considered for salvage surgery.

Nanomedical detection and downstream analysis of circulating tumor cells in head and neck patients

The establishment of novel biomarkers in liquid biopsies of cancer patients has come more into focus in prognostic and diagnostic research efforts. Due to their prognostic relevance disseminated tumor cells or circulating tumor cells are the subject of intensive research and are discussed as early diagnostic indicators for treatment failure and the formation of micrometastases. A potential association of this early-systemic tumor component with poor prognosis of cancer patients could be already demonstrated for various entities including breast, colon, lung, melanoma, ovarian and prostate cancers. Thus, the detection of circulating tumor cells seems to be also applicable for minimal-invasive monitoring of therapy progress in head and neck cancer patients. A major problem of the use in clinical routine is that circulating tumor cells could not be detected by modern imaging techniques. To overcome these limitations highly sensitive detection methods and techniques for their molecular characterization are urgently needed allowing mechanistic understanding and targeting of circulating tumor cells. Especially the medical application of nanotechnology (nanomedical methods) has made valuable contributions to the field. Here, we want to provide a comprehensive overview on (nanomedical) detection methods for circulating tumor cells and discuss their merits, pitfalls and future perspectives especially for head and neck solid squamous cell carcinoma (HNSCC) patients.

Blood Biomarkers of Uveal Melanoma: Current Perspectives

The detection of metastases in patients with a diagnosis of uveal melanoma (UM) is a controversial issue. While only 1% of the patients have detectable metastases at the time of diagnosis, up to 30% of them will develop liver metastases within 5 years of treatment. UM spreads hematogenously, therefore, blood biomarkers may be helpful for prognosis and monitoring the disease progression. Despite the great progress achieved thanks to the genetic analysis of UM biopsies, this is an invasive technique and is limited by the heterogeneity of the tumor. The present review considers the current understanding in the field regarding biomarkers for the diagnosis and prognosis of UM and its metastasis, primarily to the liver. General covered topics include non-conventional markers such as proteins previously identified in cutaneous melanoma and UM cell lines, circulating tumor cells, microRNAs (miRNA), and circulating DNA, and how each may be critical in the development of novel blood biomarkers for UM.

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.

An Update Regarding the Molecular Genetics of Melanocytic Neoplasms and the Current Applications of Molecular Genetic Technologies in Their Diagnosis and Treatment

Molecular genetic technologies are used to aid in diagnosis and treatment of borderline melanocytic tumors as an adjuvant to the gold standard histopathologic evaluation. A specific set of fluorescence in situ hybridization probes is widely used to aid in diagnosing challenging melanocytic lesions. New melanoma probe cocktails have revealed increased sensitivity and specificity in ambiguous melanocytic cases. Array comparative genomic hybridization is a more complex technology used for the work-up of diagnostically problematic Spitzoid melanocytic proliferations. Cutting-edge technologies, including next-generation sequencing and cell-free nucleic acid analysis, are promising biomarker applications for mutation detection towards personalized patient management.

Prognostic Relevance of CCDC88C (Daple) Transcripts in the Peripheral Blood of Patients with Cutaneous Melanoma

A loss of balance between G protein activation and deactivation has been implicated in the initiation of melanomas, and non-canonical Wnt signaling via the Wnt5A/Frizzled (FZD) pathway has been shown to be critical for the switch to an invasive phenotype. Daple [CCDC88C], a cytosolic guanine nucleotide exchange modulator (GEM) which enhances non-canonical Wnt5A/FZD signaling via activation of trimeric G protein, Gαi, has been shown to serve opposing roles-as an inducer of EMT and invasiveness and a potent tumor suppressor-via two isoforms, V1 (full-length) and V2 (short spliced isoform), respectively. Here we report that the relative abundance of these isoforms in the peripheral circulation, presumably largely from circulating tumor cells (CTCs), is a prognostic marker of cutaneous melanomas. Expression of V1 is increased in both the early and late clinical stages (p < 0.001, p = 0.002, respectively); V2 is decreased exclusively in the late clinical stage (p = 0.003). The two isoforms have opposing prognostic effects: high expression of V2 increases relapse-free survival (RFS; p = 0.014), whereas high expression of V1 tends to decrease RFS (p = 0.051). Furthermore, these effects are additive, in that melanoma patients with a low V2-high V1 signature carry the highest risk of metastatic disease. We conclude that detection of Daple transcripts in the peripheral blood (i.e., liquid biopsies) of patients with melanoma may serve as a prognostic marker and an effective strategy for non-invasive long-term follow-up of patients with melanoma.

Detection of Breast Cancer Cells in the Bone Marrow or Peripheral Blood: Methods and Prognostic Significance

Tumor cells can reach every anatomic district, organ and tissue through the peripheral blood circulation. Tumor cell shedding is considered an early event in the multi-phase process of metastasis, and the possibility of detecting tumor cells in the bloodstream and/or bone marrow before clinical evidence of distant metastases needs to be explored. The use of new sophisticated diagnostic and investigative techniques has boosted the study of tumor cell contamination of bone marrow and peripheral blood. Molecular techniques, such as reverse-transcriptase polymerase chain reaction, may be useful tools to reach this target, but, today, immunocytochemistry is still considered the gold standard to assess new techniques to detect isolated tumor cells in hematopoietic tissue. Little is known about the biology of isolated tumor cells in the peripheral blood or bone marrow. Two crucial points need to be evaluated: the identification of specific markers of breast cancer cells with clonogenic potential and their biologic properties, and the prognostic impact of the detection of isolated tumor cells in the bone marrow or peripheral blood stem cell collections.

Detection of Melanoma Cells in Peripheral Blood and Sentinel Lymph Nodes by RT-PCR Analysis: A Comparative Study with Immunohistochemistry

The presence of lymph node metastases is the best prognostic factor for predicting relapse or survival in melanoma patients. It has been demonstrated that melanoma metastases spread through the first lymph node(s) draining the tumor (sentinel lymph node, SN) to the lymphatic system and that detection of melanoma cells in peripheral blood directly correlates with prognosis in melanoma.

To identify lymph node metastases and circulating melanocytes, we developed a single-step reverse transcriptase-polymerase chain reaction assay (RT-PCR) for detection of two melanoma-specific markers: the tyrosinase gene, which encodes an enzyme associated with melanin synthesis, and melanoma antigen-related T-cells, which are present in tumor infiltrating T-lymphocytes. This method detects two tumor cells in a background of 107 lymphocytes.

Thirty patients with stage I–IV cutaneous melanoma entered the study. Blood samples were taken preoperatively, one month after excision of the primary melanoma lesion and the SN or total lymphadenectomy, and before the start of chemotherapy and every three months thereafter in metastatic patients. SNs were collected from 22 patients, bisected and analyzed by RT-PCR and routine pathological and immunohistochemical tests. The preliminary results indicate that RT-PCR for melanoma markers is a sensitive and valuable method for the detection of micrometastases and for early diagnosis and staging of melanoma.

Circulating tumor cells predict survival benefit from chemotherapy in patients with lung cancer

Background

This meta-analysis was to explore the clinical significance of circulating tumor cells (CTCs) in predicting the tumor response to chemotherapy and prognosis of patients with lung cancer.

Methods

We searched PubMed, Embase, Cochrane Database, Web of Science and reference lists of relevant articles. Our meta-analysis was performed by Stata software, version 12.0, with a random effects model. Risk ratio (RR), hazard ratio (HR) and 95% confidence intervals (CI) were used as effect measures.

Results

8 studies, including 453 patients, were eligible for analyses. We showed that the disease control rate (DCR) in CTCs-negative patients was significantly higher than CTCs-positive patients at baseline (RR = 2.56, 95%CI [1.36, 4.82], p < 0.05) and during chemotherapy (RR = 9.08, CI [3.44, 23.98], p < 0.001). Patients who converted form CTC-negative to positive or persistently positive during chemotherapy had a worse disease progression than those with CTC-positive to negative or persistently negative (RR = 8.52, CI [1.66, 43.83], p < 0.05). Detection of CTCs at baseline and during chemotherapy also indicated poor overall survival (OS) (baseline: HR = 3.43, CI [2.21, 5.33], p<0.001; during chemotherapy: HR = 3.16, CI [2.23, 4.48], p < 0.001) and progression-free survival (PFS) (baseline: HR = 3.16, 95%CI [2.23, 4.48], p < 0.001; during chemotherapy: HR = 3.78, CI [2.33, 6.13], p < 0.001).

Conclusions

Detection of CTCs in peripheral blood indicates poor tumor response to chemotherapy and poor prognosis in patients with lung cancer.

Tyrosinase mRNA RT-PCR Analysis as an Additional Diagnostic Tool for the Identification of Melanoma Cells in Biological Fluid Samples other than Blood: A Preliminary Report

Reverse transcription polymerase chain reaction (RT-PCR) of tyrosinase mRNA has been applied for the detection of melanoma cells in the peripheral blood, lymph nodes and bone marrow of melanoma patients. We evaluated the diagnostic accuracy of RT-PCR in comparison to standard cytology and immunocytochemistry (ICC) for the identification of melanoma cells in biological fluids other than blood. Tyrosinase expression was evaluated together with standard cytology and ICC (anti-S100, HMB-45 and Melan-A antibodies) in biological fluid samples collected from 17 melanoma patients according to the site of metastatic involvement or clinical suspicion (eight cerebrospinal fluid (CSF) samples; three pleural effusions; four ascites; one bile sample, one pericardial effusion); 17 samples collected from patients with non-melanoma metastatic cancer were used as controls. Tyrosinase expression in the biological fluid sample was compared with the expression determined at the same time in peripheral blood. Positive tyrosinase expression was found in 12/17 melanoma and 3/17 non-melanoma cancer patients. Cytology/ICC showed the presence of neoplastic cells in only 7/12 melanoma samples with positive tyrosinase expression: radiological evidence of disease involvement was found in all these patients (three meningeal, two pleural, two peritoneal). Clear-cut radiological evidence of disease involvement at the sampling site was found in the five patients with negative cytology/ICC and positive RT-PCR (one CSF; four serous membrane effusions); all patients died of disease progression within four months of sampling. The five patients who were negative for both cytology/ICC and RT-PCR did not show any clinical evidence of disease recurrence at the sampling site. Only five of the 12 metastatic patients with positive tyrosinase expression in biological fluid showed positivity for tyrosinase in the peripheral blood. These preliminary results suggest that the analysis of biological fluids other than blood could be considered as a new potential clinical field of application for the tyrosinase mRNA assay.

Cytokeratin 17 mRNA as a prognostic marker of oral squamous cell carcinoma

Despite diagnostic and therapeutic advances, the 5-year survival rate of oral squamous cell carcinoma (OSCC) remains between 70–80% due to recurrences and secondary metastases to cervical lymph nodes. It is difficult to find these recurrences and metastases postoperatively, thus, careful follow-up is recommended. Cytokeratins (CKs) are intermediate filaments of the cytoskeleton and candidate prognostic biomarkers for OSCC, as they are overexpressed in OSCC compared with normal mucosa. The aim of the present study was to determine the relative levels of occurrence of 3 CK mRNA (CK17, CK19, CK20) transcripts in peripheral blood mononuclear cells (PBMC) using reverse transcription-quantitative polymerase chain reaction. The study comprised pre- and post-operative PBMC samples from 19 OSCC patients. In the good-prognosis group, 10 of 13 patients demonstrated reduced CK17 mRNA expression post-operatively, compared with pre-operative samples, conversely, only 3 of 6 patients in the poor-prognosis group had reduced post-operative CK17 mRNA expression. This difference was statistically significant (P<0.01). The disease-free survival rate of the group with reduced post-operative CK17 mRNA expression was significantly increased compared with the elevated CK17 mRNA group (P<0.01); however, the overall survival rates of the two groups were not significantly different. Neither CK19 mRNA nor CK20 mRNA were significantly expressed in the PBMC of OSCC patients. Overall, CK17 mRNA expression may be a useful prognostic biomarker for OSCC.

Targeting cholesterol transport in circulating melanoma cells to inhibit metastasis

Despite recent breakthroughs in targeted- and immune-based therapies, rapid development of drug resistance remains a hurdle for the long-term treatment of patients with melanoma. Targeting metastatically spreading circulating tumor cells (CTCs) may provide an additional approach to manage melanoma. This study investigates whether targeting cholesterol transport in melanoma CTCs can retard metastasis development. Nanolipolee-007, the liposomal form of leelamine, reduced melanoma metastasis in both a novel in vitro flow system mimicking the circulating system and in experimental as well as spontaneous animal metastasis models, irrespective of the BRAF mutational status of the CTCs. Leelamine led to cholesterol trapping in lysosomes, which subsequently shut down receptor-mediated endocytosis, endosome trafficking, and inhibited the major oncogenic signaling cascades important for survival such as the AKT pathway. As pAKT is important in CTC survival, inhibition by targeting cholesterol metabolism led to apoptosis, suggesting this approach might be particularly effective for those CTCs having high levels of pAKT to aid survival in the circulation system.

Targeting Melanoma with Cancer-Killing Viruses

Melanoma is the deadliest skin cancer with ever-increasing incidence. Despite the development in diagnostics and therapies, metastatic melanoma is still associated with significant morbidity and mortality. Oncolytic viruses (OVs) represent a class of novel therapeutic agents for cancer by possessing two closely related properties for tumor reduction: virus-induced lysis of tumor cells and induction of host anti-tumor immune responses. A variety of viruses, either in "natural" or in genetically modified forms, have exhibited a remarkable therapeutic efficacy in regressing melanoma in experimental and/or clinical studies. This review provides a comprehensive summary of the molecular and cellular mechanisms of action of these viruses, which involve manipulating and targeting the abnormalities of melanoma, and can be categorized as enhancing viral tropism, targeting the tumor microenvironment and increasing the innate and adaptive antitumor responses. Additionally, this review describes the "biomarkers" and deregulated pathways of melanoma that are responsible for melanoma initiation, progression and metastasis. Advances in understanding these abnormalities of melanoma have resulted in effective targeted and immuno-therapies, and could potentially be applied for engineering OVs with enhanced oncolytic activity in future.

Minimal residual disease in melanoma: circulating melanoma cells and predictive role of MCAM/MUC18/MelCAM/CD146

Circulating tumour cells (CTCs), identified in numerous cancers including melanoma, are unquestionably considered valuable and useful as diagnostic and prognostic markers. They can be detected at all melanoma stages and may persist long after treatment. A crucial step in metastatic processes is the intravascular invasion of neoplastic cells as circulating melanoma cells (CMCs). Only a small percentage of these released cells are efficient and capable of colonizing with a strong metastatic potential. CMCs' ability to survive in circulation express a variety of genes with continuous changes of signal pathways and proteins to escape immune surveillance. This makes it difficult to detect them; therefore, specific isolation, enrichment and characterization of CMC population could be useful to monitor disease status and patient clinical outcome. Overall and disease-free survival have been correlated with the presence of CMCs. Specific melanoma antigens, in particular MCAM (MUC18/MelCAM/CD146), could be a potentially useful tool to isolate CMCs as well as be a prognostic, predictive biomarker. These are the areas reviewed in the article.

Future of circulating tumor cells in the melanoma clinical and research laboratory settings

Circulating tumor cells (CTC) have become a field of interest for oncologists based on the premise that they constitute the underpinning for metastatic dissemination. The lethal nature of cancer is no longer attributed to solid tumor formation, but rather to the process of metastasis; shifting the focus of current studies towards the isolation and identification of metastatic progenitors, such as CTCs. CTCs originate from primary tumor masses that undergo morphologic and genetic alterations, which involve the release of mesenchymal-like cancer cells into the bloodstream, capable of invading nearby tissues for secondary tumor development. Cancerous cells contained in the primary tumor mass acquire the motile mesenchymal phenotype as a result of the Epithelial-to-Mesenchymal Transition, where substantial variations in protein expression and signaling pathways take place. CTCs that migrate from the primary tumor, intravasate into the systemic vasculature, are transported through the bloodstream, and invade tissues and organs suitable for secondary tumor development. While only a limited number of CTCs are viable in the bloodstream, their ability to elude the immune system, evade apoptosis and successfully metastasize at secondary tumor sites, makes CTCs promising candidates for unraveling the triggers that initiates the metastatic process. In this article, these subjects are explored in greater depth to elucidate the potential use of CTCs in the detection, disease staging and management of metastatic melanoma.

Strategies for Isolation and Molecular Profiling of Circulating Tumor Cells

Cancer is the leading cause of death by disease worldwide, and metastasis is responsible for more than 90% of the mortality of cancer patients. Metastasis occurs when tumor cells leave the primary tumor, travel through the blood stream as circulating tumor cells (CTCs), and then colonize secondary tumors at sites distant from the primary tumor. The capture, identification, and analysis of CTCs offer both scientific and clinical benefits. On the scientific side, the analysis of CTCs could help elucidate possible genetic alterations and signaling pathway aberrations during cancer progression, which could then be used to find new methods to stop cancer progression. On the clinical side, non-invasive testing of a patient's blood for CTCs can be used for patient diagnosis and prognosis, as well as subsequent monitoring of treatment efficacy in routine clinical practice. Additionally, investigation of CTCs early in the progression of cancer may reveal targets for initial cancer detection and for anti-cancer treatment. This chapter will evaluate strategies and devices used for the isolation and identification of CTCs directly from clinical samples of blood. Recent progress in the understanding of the significance of both single CTCs and circulating tumor microemboli will be discussed. Also, advancements in the use of CTC-based liquid biopsy in clinical diagnosis and the potential of CTC-based molecular characterization for use in clinical applications will be summarized.

Is it feasible to detect epidermal growth factor receptor mutations in circulating tumor cells in nonsmall cell lung cancer?: A meta-analysis

BACKGROUND

The value of circulating tumor cells (CTCs) in detecting epidermal growth factor receptor (EGFR) mutations in patients with nonsmall cell lung cancer (NSCLC) is controversial. We performed a meta-analysis to investigate the diagnostic significance of CTCs with tumor tissues as the standard control.

METHODS

A systematic literature search, including papers published until November 26, 2015, was performed using PubMed, Medline, Embase, Web of Science, and the China National Knowledge Infrastructure, and the references of retrieved articles were screened. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated according to the data selection from the included studies. The evaluation indexes of the diagnostic performance were the summary receiver operating characteristic curve (SROC) and area under the SROC (AUSROC).

RESULTS

Eight eligible articles with a total of 170 participants were identified in our meta-analysis. The pooled sensitivity and specificity were 0.91 [95% CI: 0.55-0.99] and 0.99 [95% CI: 0.59-1.00]. The positive likelihood ratio and negative likelihood ratio were 68 [95% CI: 1.4-3364] and 0.09 [95% CI: 0.01-0.64], respectively. The DOR was 788 [95% CI: 9-71884]. The high diagnostic performance of CTCs in detecting EGFR mutations was indicated by the AUSROC of 0.99 [95% CI: 0.98-1.00].

CONCLUSIONS

CTCs are a feasible and highly specific biomarker for detecting the EGFR mutation status in NSCLC patients.

High intensity focused ultrasound enhances anti-tumor immunity by inhibiting the negative regulatory effect of miR-134 on CD86 in a murine melanoma model

HIFU has been demonstrated to enhance anti-tumor immunity, however, the mechanism of which has not been well elucidated. Emerging evidence indicates that miRNAs play important roles in immune response. In this study, we used the B16F10 melanoma allograft mouse model to investigate the role of miRNAs in HIFU-enhanced anti-tumor immunity. We found that HIFU treatment decreased circulating B16F10 cells and pulmonary metastasis nodules while increased IFN-γ and TNF-α in the peripheral blood and cumulative mouse survival, which was associated with inhibition of miR-134 expression and activation of CD86 expression in tumor tissues. Further, we determined that miR-134 directly binds to the 3′UTR of CD86 mRNA to suppress its expression in B16F10 cells. When B16F10 cells transfected with miR-134 were co-cultured with normal splenic lymphocytes, the secretion of IFN-γ and TNF-α from lymphocytes was reduced and B16F10 cell survival was increased. HIFU exposure efficiently decreased miR-134 while increased CD86 expression in B16F10 cells in vitro. CD86 knockdown with siRNA markedly rescued the viability of HIFU-treated B16F10 cells that co-cultured with lymphocytes. Altogether, our results suggest that HIFU down-regulates miR-134 to release the inhibition of miR-134 on CD86 in melanoma cells, thereby enhancing anti-tumor immune response.

Stem-like features of cancer cells on their way to metastasis

More than 90 % of cancer-related deaths are due to the development of a systemic metastatic disease. Clearly, much remains to be understood about the biological principles that govern human cancer metastasis, aiming at the ambitious objective to decrease metastasis-related mortality in patients. For many years, research on metastasis has been conducted in great part on experimental mouse models, mainly because of the difficulties in sampling, longitudinal studies, and molecular interrogation of a human metastatic disease. However, recently, extraordinary advances in microfluidic technologies are allowing the isolation and characterization of human circulating tumor cells (CTCs) that escaped a primary tumor mass and are in the process of seeding a distant metastasis. Analysis of human CTCs has now revealed important features of cancer metastasis, such as the high metastatic potential of CTC-clusters compared to single CTCs, the dynamic expression of epithelial and mesenchymal markers on CTCs during treatment, and the possibility to culture CTCs from patients for a real-time and individualized testing of drug susceptibility. Nevertheless, several aspects of CTC biology remain unsolved, such as the characterization of the stem-like cell population among human CTCs. Here, we focus on describing the latest findings in the CTC field, and discuss them in the context of cancer stem cell biology. Defining the molecular features of those few metastasis-initiating, stem-like CTCs holds the exceptional promise to develop metastasis-tailored therapies for patients with cancer.

REVIEWERS

This article was reviewed by Elisa Cimetta, Luca Pellegrini and Sirio Dupont (nominated by LP).

The potential for liquid biopsies in the precision medical treatment of breast cancer

Currently the clinical management of breast cancer relies on relatively few prognostic/predictive clinical markers (estrogen receptor, progesterone receptor, HER2), based on primary tumor biology. Circulating biomarkers, such as circulating tumor DNA (ctDNA) or circulating tumor cells (CTCs) may enhance our treatment options by focusing on the very cells that are the direct precursors of distant metastatic disease, and probably inherently different than the primary tumor's biology. To shift the current clinical paradigm, assessing tumor biology in real time by molecularly profiling CTCs or ctDNA may serve to discover therapeutic targets, detect minimal residual disease and predict response to treatment. This review serves to elucidate the detection, characterization, and clinical application of CTCs and ctDNA with the goal of precision treatment of breast cancer.

Liquid biopsy utility for the surveillance of cutaneous malignant melanoma patients

Cutaneous melanoma is one of the highest incident-rate cancers with increasing prevalence in Western societies. Despite the advent of new approved therapeutics, the 5-year overall survival rate of stage IV melanoma patients remains below 15%. Current treatments for late stage disease have shown higher efficacy when treated at a lower disease burden. Thus, blood-based biomarkers capable of detecting melanoma prior to clinically evident distant metastasis, will improve the treatment and outcomes for melanoma patients. To that end, effective treatment of melanoma necessitates identification of patients at risk for developing distant metastases. Furthermore, employing blood biomarkers that monitor cancer progression over the course of treatment is a promising solution to post-treatment drug resistance often developed in melanoma patients. Non-invasive blood biomarker assays allow for regular dynamic monitoring of disease. "Liquid Biopsy" of blood, which exploits circulating tumor cells (CTCs), cell-free circulating tumor DNA (ctDNA) and cell-free circulating microRNA (cmiRNA), has been shown to detect prognostic factors for relapse in AJCC stage III and stage IV melanoma patients. Moreover, molecular characterization of CTC and analysis of various forms of ctDNA present promising potential in development of individualized therapy for melanoma patients. New approaches such as massive parallel sequencing (MPS) provide a comprehensive view of the disease progression, allowing for the selection of therapeutic options for individual patients. With advancements of improving molecular assays, liquid biopsy analysis as a powerful, routine clinical assay for melanoma patients, is highly promising prospective.

Circulating Tumor Cells, DNA, and mRNA: Potential for Clinical Utility in Patients With Melanoma

: Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and messenger RNA (mRNA), collectively termed circulating tumor products (CTPs), represent areas of immense interest from scientists' and clinicians' perspectives. In melanoma, CTP analysis may have clinical utility in many areas, from screening and diagnosis to clinical decision-making aids, as surveillance biomarkers or sources of real-time genetic or molecular characterization. In addition, CTP analysis can be useful in the discovery of new biomarkers, patterns of treatment resistance, and mechanisms of metastasis development. Here, we compare and contrast CTCs, ctDNA, and mRNA, review the extent of translational evidence to date, and discuss how future studies involving both scientists and clinicians can help to further develop this tool for the benefit of melanoma patients.

IMPLICATIONS FOR PRACTICE

Scientific advancement has enabled the rapid development of tools to analyze circulating tumor cells, tumor DNA, and messenger RNA, collectively termed circulating tumor products (CTPs). A variety of techniques have emerged to detect and characterize melanoma CTPs; however, only a fraction has been applied to human subjects. This review summarizes the available human data that investigate clinical utility of CTP in cancer screening, melanoma diagnosis, prognosis, prediction, and genetic or molecular characterization. It provides a rationale for how CTPs may be useful for future research and discusses how clinicians can be involved in developing this exciting new technology.

Detection of tumour cells in the bloodstream of patients with uveal melanoma: influence of surgical manipulation on the dissemination of tumour cells in the bloodstream

AIM

The detection of circulating tumour cells in the bloodstream before and after surgical manipulation, and the qualitative detection of potential shedding of tumour cells during surgical manipulation of patients with uveal melanoma.

METHODS

202 patients treated for a newly diagnosed uveal melanoma were included in the study. Blood samples were acquired 24 h before and 30 min after the basic surgical steps. Detection of potential circulating melanoma cells was extrapolated from the presence of tyrosinase and MelanA/Mart1 transcripts by reverse transcription PCR.

RESULTS

Based on the measurement of tyrosinase transcripts, as a result of the first and second surgical manipulation there were three and zero transitions from negative to positive respectively, while there were two and one transitions from positive to negative, respectively. According to MelanA/Mart1 transcripts, there were 19 and 5 transitions from negative to positive respectively, and 15 and 2 transitions from positive to negative, respectively. No statistically significant differences were documented, concerning the presence of circulating tumour cells in the blood samples acquired before and after the first surgical manipulation or the second one.

CONCLUSION

The change in the percentage of patients with detected tumour cells in their bloodstream was not statistically significant. The frequent shifts from negative to positive samples as well as from positive to negative samples comparing preoperative to postoperative samples indicates discontinuous shedding or variation due to measurements close to the threshold of detection. As a conclusion, the surgical manipulation does not seem to have a measurable contribution to the spread of melanoma cells in the bloodstream.

Circulating biomarkers in malignant melanoma

Melanoma is an aggressive tumor with increasing incidence worldwide. Biomarkers are valuable tools to minimize the cost and improve efficacy of treatment of this deadly disease. Serological markers have not widely been introduced in routine clinical practice due to their insufficient diagnostic sensitivity and specificity. It is likely that the lack of objective responses with traditional treatment hinder biomarker research and development in melanoma. Recently, new drugs and therapies have, however, emerged in advanced melanoma with noticeable objective response ratio and survival. In this new scenario, serological tumor markers should be revisited. In addition, other potential circulating biomarkers such as cell-free DNA, exosomes, microRNA, and circulating tumor cells have also been identified. In this review, we summarize classical and emerging tumor markers and discuss their possible roles in emerging therapeutics.

An electrochemical immunosensing method for detecting melanoma cells

An electrochemical immunosensing method was developed to detect melanoma cells based on the affinity between cell surface melanocortin 1 receptor (MC1R) antigen and anti-MC1R antibody (MC1R-Ab). The MC1R-Abs were immobilized in amino-functionalized silica nanoparticles (n-SiNPs)-polypyrrole (PPy) nanocomposite modified on working electrode surface of screen-printed electrode (SPE). Cyclic voltammetry was employed, with the help of redox mediator ([Fe(CN)6](3-)), to measure the change in anodic oxidation peak current arising due to the specific interaction between MC1R antigens and MC1R-Abs when the target melanoma cells are present in the sample. Various factors affecting the sensor performance, such as the amount of MC1R-Abs loaded, incubation time with the target melanoma cells, the presence of interfering non-melanoma cells, were tested and optimized over different expected melanoma cell loads in the range of 50-7500 cells/2.5 mL. The immunosensor is highly sensitive (20 cells/mL), specific, and reproducible, and the antibody-loaded electrode in ready-to-use stage is stable over two weeks. Thus, in conjunction with a microfluidic lab-on-a-chip device our electrochemical immunosensing approach may be suitable for highly sensitive, selective, and rapid detection of circulating tumor cells (CTCs) in blood samples.

Limited genomic heterogeneity of circulating melanoma cells in advanced stage patients

Purpose. Circulating melanoma cells (CMCs) constitute a potentially important representation of time-resolved tumor biology in patients. To date, genomic characterization of CMCs has been limited due to the lack of a robust methodology capable of identifying them in a format suitable for downstream characterization. Here, we have developed a methodology to detect intact CMCs that enables phenotypic, morphometric and genomic analysis at the single cell level. Experimental design. Blood samples from 40 metastatic melanoma patients and 10 normal blood donors were prospectively collected. A panel of 7 chondroitin sulfate proteoglycan 4 (CSPG4)-specific monoclonal antibodies (mAbs) was used to immunocytochemically label CMCs. Detection was performed by automated digital fluorescence microscopy and multi-parametric computational analysis. Individual CMCs were captured by micromanipulation for whole genome amplification and copy number variation (CNV) analysis. Results. Based on CSPG4 expression and nuclear size, 1-250 CMCs were detected in 22 (55%) of 40 metastatic melanoma patients (0.5-371.5 CMCs ml(-1)). Morphometric analysis revealed that CMCs have a broad spectrum of morphologies and sizes but exhibit a relatively homogeneous nuclear size that was on average 1.5-fold larger than that of surrounding PBMCs. CNV analysis of single CMCs identified deletions of CDKN2A and PTEN, and amplification(s) of TERT, BRAF, KRAS and MDM2. Furthermore, novel chromosomal amplifications in chr12, 17 and 19 were also found. Conclusions. Our findings show that CSPG4 expressing CMCs can be found in the majority of advanced melanoma patients. High content analysis of this cell population may contribute to the design of effective personalized therapies in patients with melanoma.

Circulating tumour cells as tumour biomarkers in melanoma: detection methods and clinical relevance

Circulating tumour cells (CTCs) are cells of solid tumour origin detectable in the peripheral blood. Their occurrence is considered a prerequisite step for establishing distant metastases. Metastatic melanoma was the first malignancy in which CTCs were detected and numerous studies have been published on CTC detection in melanoma at various stages of disease. In spite of this, there is no general consensus as to the clinical utility of CTCs in melanoma, largely due to conflicting results from heterogeneous studies and discrepancies in methods of detection between studies. In this review, we examine the possible clinical significance of CTCs in cutaneous, mucosal and ocular melanoma, focusing on detection methods and prognostic value of CTC detection.

CTC enumeration and characterization: moving toward personalized medicine

The primary cause of tumor-related death in breast cancer (BC) is still represented by distant metastasization. The dissemination of tumor cells from the primary tumor to distant sites through bloodstream cannot be early detected by standard imaging methods. The enumeration of circulating tumor cells (CTCs) represents an effective prognostic and predictive biomarker, which is able to monitor efficacy of adjuvant therapies, detect early development of (micro)metastases and at last, assess therapeutic responses of advanced disease earlier than traditional imaging methods. Moreover, since repeated tissue biopsies are invasive, costly and not always feasible, the assessment of tumor characteristics on CTCs, by a peripheral blood sample as a 'liquid biopsy', represents an attractive opportunity. The implementation of molecular and genomic characterization of CTCs could contribute to improve the treatment selection and thus, to move toward more personalized treatments. This review describes the current state of the art on CTC detection strategies, the evidence to demonstrate their clinical validity, and their potential impact for both future clinical trial design and, decision-making process in our daily practice.

Circulating melanoma cells in the diagnosis and monitoring of melanoma: an appraisal of clinical potential

Circulating melanoma cells (CMCs) are thought to be the foundation for metastatic disease, which makes this cancer especially lethal. Cancer cells contained in the primary tumor undergo genotypic and phenotypic changes leading to an epithelial-to-mesenchymal transition, during which numerous changes occur in signaling pathways and proteins in the cells. CMCs are then shed off or migrate from the primary tumor and intravasate the vasculature system. A few CMCs are able to survive in the circulation through expression of a variety of genes and also by evading immune system recognition to establish metastases at distant sites after extravasating from the vessels. The presence of CMCs in the blood of a melanoma patient can be used for disease staging, predicting metastasis development, and evaluating the efficacy of therapeutic agents. Overall survival and disease-free duration can also be correlated with the presence of CMCs. Finally, analysis of CMCs for druggable therapeutic gene targets could lead to the development of personalized treatment regimens to prevent metastasis. Thus, the study of CMCs shows promise for the detection, staging, and monitoring of disease treatment, as well as for determination of prognosis and predicting overall disease-free survival. These are the areas reviewed in this article.

Sequential molecular analysis of circulating MCAM/MUC18 expression: a promising disease biomarker related to clinical outcome in melanoma

MCAM/MUC18 is a cell adhesion molecule associated with higher incidence of relapse in melanoma. The purpose of our study was to evaluate its role as a promising disease biomarker of progression through sequential molecular MCAM/MUC18 RT-PCR assay on serial blood samples collected during the clinical follow-up of 175 melanoma patients in different American Joint Committee on Cancer (AJCC) stages. MCAM/MUC18 molecular detection, found at least once in 22 out of the 175 patients, was significantly associated with poor prognosis and death (p < 0.001), regardless of the AJCC stages. Positive expression, either if primarily present or later acquired, was associated with melanoma progression, whereas patients primarily negative or with subsequent loss gained clinical remission or stable disease, even if in advanced stages (p < 0.005). Six AJCC advanced stages always MCAM/MUC18 negative are in complete remission or with a stable disease (p < 0.007). Semiquantitative immunohistochemical MCAM/MUC18 staining on corresponding primary melanomas was related to peripheral molecular expression. Correlations between circulating molecular and tissutal immunohistochemical detection, primary tumour thickness, AJCC stages and clinical outcome were statistically evaluated using Student's t test, ANOVA, Spearman's rank correlation test, Pearson χ (2)-test and McNemar's test. In our investigation, MCAM/MUC18 expression behaves as a "molecular warning of progression" even in early AJCC patients otherwise in disease-free conditions. Achievement of this molecule predicted the emergence of a clinically apparent status, whereas absence or persistent loss was related to a stable disease or to a disease-free status. If confirmed in larger case series, MCAM/MUC18 molecular expression could predict good or poor clinical outcome, possibly becoming a promising prognostic factor.

Pathways and therapeutic targets in melanoma

This review aims to summarize the current knowledge of molecular pathways and their clinical relevance in melanoma. Metastatic melanoma was a grim diagnosis, but in recent years tremendous advances have been made in treatments. Chemotherapy provided little benefit in these patients, but development of targeted and new immune approaches made radical changes in prognosis. This would not have happened without remarkable advances in understanding the biology of disease and tremendous progress in the genomic (and other "omics") scale analyses of tumors. The big problems facing the field are no longer focused exclusively on the development of new treatment modalities, though this is a very busy area of clinical research. The focus shifted now to understanding and overcoming resistance to targeted therapies, and understanding the underlying causes of the heterogeneous responses to immune therapy.