Circulating tumor cells (CTCs) have been studied using multiple technical approaches for interrogating various cancers, as they allow for the real-time assessment of tumor progression, disease recurrence, treatment response, and tumor molecular profiling without the need for a tumor tissue biopsy. Here, we will review studies from the last 15 years on the assessment of CTCs in cutaneous melanoma patients in relation to different clinical outcomes. The focus will be on CTC detection in blood samples obtained from cutaneous melanoma patients of different clinical stages and treatments utilizing multiple platforms. Assessment of multiple molecular melanoma-associated antigen (MAA) markers by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was the most common assay allowing for the improvement of assay sensitivity, tumor heterogeneity, and to predict patient outcomes. Multicenter studies demonstrate the utility of CTC assays reducing the bias observed in single- center trials. The recent development of CTC enrichment platforms has provided reproducible methods. CTC assessment enables both multiple mRNAs and DNAs genomic aberration profiling. CTC provides specific important translational information on tumor progression, prediction of treatment response, and survival outcomes for cutaneous melanoma patients. The molecular studies on melanoma CTCs have provided and may set standards for other solid tumor CTC analyses.
Keywords: biomarkers; circulating tumor cells; liquid biopsy; melanoma; molecular diagnostic techniques.