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

Area of Science:

• Oncology
• Cancer Biology
• Diagnostic Assays

Background:

• Metastatic melanoma is an aggressive cancer with poor survival rates.
• Detecting circulating melanoma cells (CMCs) has potential clinical utility, but results are inconsistent.
• Existing CMC detection methods lack standardization and exhibit variable sensitivity.

Purpose of the Study:

• To develop and validate a novel EPithelial ImmunoSPOT (EPISPOT) assay for detecting viable CMCs.
• To compare the sensitivity and prognostic value of the S100-EPISPOT assay against the CellSearch® CMC kit.
• To assess the potential clinical utility of the S100-EPISPOT assay in melanoma management.

Main Methods:

• Development of the S100-EPISPOT assay detecting viable CMCs via S100 protein secretion.
• Comparative analysis of S100-EPISPOT and CellSearch® using blood samples from metastatic melanoma patients.
• Statistical evaluation of assay sensitivity and association with overall survival.

Main Results:

• The S100-EPISPOT assay demonstrated significantly higher sensitivity in detecting CMCs compared to CellSearch®.
• A higher percentage of patients had ≥2 CMCs detected by S100-EPISPOT (48%) versus CellSearch® (21%).
• Only CellSearch® results showed a significant association with overall survival (p = 0.006).

Conclusions:

• The S100-EPISPOT assay offers improved sensitivity for CMC detection in metastatic melanoma.
• The higher sensitivity suggests potential for S100-EPISPOT in early relapse detection and treatment monitoring.
• Further studies are warranted to validate the prognostic value and clinical application of the S100-EPISPOT assay.