In Vivo Liquid Biopsy of Melanoma (Cytophone)

The majority of melanoma deaths are associated with metastasis that are formed by cancer cells shedding from the primary tumor that enter the circulation and spread to distant organs via blood circulation. These cells in blood are referred to as circulating tumor cells (CTCs). Growing evidence suggests that metastasis is an early event in melanoma patients, often occurring before metastases are clinically detectable. Therefore, detection of CTCs using liquid biopsy assays should be considered as an effective tool to diagnose early the risk of metastasis progression. Taking into account the link of CTCs with metastasis, CTCs have an advantage over many other biomarkers in identifying patients for early therapeutic intervention at a stage when the disease is still manageable and possibly curable. Overall, CTCs are in the blood circulation in early stage disease, yet they are typically detected in later stage disease. Currently, the main issue restricting the use of CTCs for early melanoma detection relates to the low sensitivity of existing assays due to assessment of limited blood volume (i.e., blood samples in vitro). To maximize the blood volume available for analysis, in vivo CTC enumeration without labelling in a large blood volume using the Cytophone device was developed by our team. The Cytophone represents a photoacoustic (PA) flow cytometry (PAFC) diagnostic platform. Our feasibility clinical study has demonstrated the detection of CTCs in 49 of 50 melanoma patients (sensitivity 98%) and in 0 of 18 in healthy subjects (control group). The investigators received clinical evidence of the Cytophone's capability to diagnose 0.001 CTCs/mL which is significantly higher than sensitivity of existing testing methodologies. This threshold of the sensitivity is 130-times better than the sensitivity of the in vitro CellSearch (Menarini) assay which is only assay approved by FDA for clinical testing of CTCs (1 CTC in 7.5 mL; 0.13 CTCs/mL). The Goal of this clinical study is to determine whether the Cytophone can be used for in vivo detection and enumeration of circulating tumor cells (CTCs) in the melanoma patients at different disease stages with focus on early diagnosis, early assessment of disease recurrence and monitoring of therapy efficiency. It is expected that the detection limit of CTCs will be improved at least an order of magnitude compared to the detection limits of existing methods. The test results are intended to use in conjunction with other clinical diagnostic methods. The investigators hypothesize that our CTC assay, in vivo, provides earlier, rapid and more accurate diagnosis and prognosis of metastasis progression in melanoma patients. To achieve our goal, the investigators will accomplish the following primary and secondary objectives: The primary objectives: 1. Obtain evidence that a positive Cytophone CTC test indicates a risk of metastasis development. 2. Define thresholds of CTC counts that correlate with melanoma recurrence and progression of metastatic disease. The secondary objective: 1\. Determine if the Cytophone diagnoses the risk of melanoma metastasis progression and recurrence earlier than existing methods.