ERBB2 and neoplasm: Tumor‐specific cell surface antigens, such as epithelial cell adhesion molecule (EpCAM), are targeted for the positive enrichment: CellSearch®, which is the only US Food and Drug Administration‐approved platform, MACS®, and MagSweeper are examples that may use EpCAM‐based or other markers, while AdnaTest uses a cocktail of antibodies against multiple antigens (e.g., EpCAM, EGFR, and HER2).