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Melanin exists in the most of melanoma lesions. Melanin plays an important role in melanoma progression, metastasis, therapy response, and the overall survival of patients. Therefore, melanin is a critical target for melanoma diagnosis and therapy. Many melanin targeting probes, such as radioisotope-labeled benzamide analogs, have been developed for melanoma diagnosis using positron emission tomography (PET). The N-(2-(diethylamino)-ethyl)-18F-5-fluoropicolinamide (18F-P3BZA) probe is one of the benzamide analogs and has been preliminarily tested for clinical diagnosis of melanoma in our recent studies. It has shown high specificity and favorable in vivo performance for PET of melanoma. Herein, we describe the detailed synthesis protocol of 18F-P3BZA and PET/CT imaging procedure for animal models and patients.Metastatic melanoma is one of the most aggressive types of cancers, diffused worldwide and with a significant percentage of lethality. The employment of animal models to test therapeutic strategies against melanoma growth and metastatic spread is of key relevance for cancer biologists. In this regard, the count of metastatic foci in murine lung tissue is one of the recognized methods to monitor macrometastases of melanoma. Here, we illustrate a clonogenic assay method to detect with high sensitivity the presence of single melanoma cells (micrometastases) at the pulmonary level when metastatic foci are still not detectable in the tissue. This method allows for high precision detection and quantification of melanoma metastatic spread to the lung at early stages.We present the assay based on multimarker analysis of mRNA transcripts associated with melanocytic cells detected in lymphatic fluid collected after lymph node dissection. Positive results of reverse transcriptase polymerase chain reaction (RT-PCR) test have a strong relationship with melanoma recurrence and disease-specific survival time in stage III melanoma.The lymph node microenvironment is extremely dynamic and responds to immune stimuli in the host by reprogramming immune, stromal, and endothelial cells. In normal physiological conditions, the lymph node will initiate an appropriate immune response to clear external threats that the host may experience. However, in metastatic disease, cancer cells often colonize local lymph nodes, disrupt immune function, and even leave the lymph node to create additional metastases. Understanding how cancer cells enter, colonize, survive, proliferate, and interact with other cell types in the lymph node is challenging. [https://www.selleckchem.com/products/Nanchangmycin.html Nanchangmycin] Here, we describe the use of photoconvertible fluorescent proteins to label and trace the fate of cancer cells once they enter the lymph node.Circulating extracellular vesicles in biofluids have become an interesting approach to analyse disease biomarkers. There are multiple methods for isolation of extracellular vesicles, though differential ultracentrifugation is still considered as the gold-standard isolation technique for exosomes. Furthermore, exosomes purified by this method have been demonstrated to display functional activity in vitro and in vivo and exhibit great versatility for subsequent analysis including proteomics, electron microscopy, mass spectrometry, or nucleic acid analysis. Here, we describe the method for isolation of exosomes from lymphatic exudate (seroma) obtained postlymphadenectomy for liquid biopsy approaches.Most human cells release extracellular vesicles (EVs) of different sizes and composition, containing biomolecules characteristic from the originating tissue. In consequence, when EVs derive from a cancer cell, they also contain tumor antigens. Therefore, isolating and characterizing tumor-derived EVs has attracted great interest as an invaluable source of biomarkers, both for diagnosis and stratification of cancer. In this chapter, we describe a method for flow cytometry assessment of melanoma-derived EVs which are firstly captured onto antibody-coated beads recognizing either a common EV marker, namely, a tetraspanin, or a tumor antigen like the stress-related molecules MICA or PDL1. Then, after staining with a fluorophore-conjugated antibody directed against a different protein present on the EV surface, the EV-bead complex can be visualized in a conventional flow cytometer. The technique allows detection of proteins present on EVs isolated from tissue culture supernatants of melanoma cell lines and, more importantly, directly from plasma.Tumor-derived exosomes (TEX), a subset of small extracellular vesicles (EVs) which originate from the endocytic compartment of tumor cells, are emerging as key players in cancer progression. TEX circulate freely in patients' body fluids and transfer bioactive cargos from tumor to various recipient cells. The molecular cargo of melanoma cell-derived exosomes (MTEX) mimics that of the tumor, and MTEX serve as a liquid biopsy that provides potentially useful information for cancer diagnosis, prognosis, or responses to therapy. Plasma of melanoma patients contains a mix of MTEX and exosomes produced by nonmalignant cells (NMTEX). Isolation of these exosome subtypes from the bulk of plasma exosomes is necessary to evaluate contributions of each as potential biomarkers of melanoma progression and outcome. Here, methods for separation of MTEX from T cell-derived exosomes from a single small volume of plasma and their subsequent molecular and functional characterization are described. Following size exclusion chromatography (SEC) to isolate total plasma exosomes, immune affinity-based capture of MTEX with anti-CSPG4 antibody and then of exosomes produced by T cells with anti-CD3 antibody is used to sequentially isolate the two subsets. This immune capture method enables the recovery of MTEX and CD3+ exosomes in quantities sufficient both for molecular profiling by flow cytometry or western blotting and for functional analyses.Cells release extracellular vesicles (EVs) that can be detected both in vivo and in cell culture medium. Among EVs, exosomes are 50-150 nm vesicles that are systematically packaged into multivesicular bodies for release into the external environment. In cancer, these intentionally packaged exosomes carry a payload of proteins such as RNAs and surface receptors that facilitate the reprogramming of proximal cells to assemble a protumor microenvironment. Exosomes have been implicated as an important intermediary extracellular communication pathway between cells, including in melanoma. Human melanoma-derived exosomes (HMEX) have been demonstrated to modulate the extracellular environment and inhibit immune cell activation. There are many methods to isolate and enrich for exosomes and the method applied can impact yield and purity of the isolates. In this chapter we describe the REIUS (rapid exosome isolation using ultrafiltration and size exclusion chromatography) method to isolate HMEX from melanoma cell cultures and then demonstrate their enrichment using molecular and microscopic approaches.