Cells (Jul 2019)

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

  • Laure Cayrefourcq,
  • Aurélie De Roeck,
  • Caroline Garcia,
  • Pierre-Emmanuel Stoebner,
  • Fanny Fichel,
  • Françoise Garima,
  • Françoise Perriard,
  • Jean-Pierre Daures,
  • Laurent Meunier,
  • Catherine Alix-Panabières

DOI
https://doi.org/10.3390/cells8070755
Journal volume & issue
Vol. 8, no. 7
p. 755

Abstract

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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.

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