A limited correlation was observed between the HER2 status of CTCs detected by CellSearch® or AdnaTest® and the HER2 status of the primary tumor (e.g., with CellSearch®, 33% of patients with a HER2‐negative tumor had HER2‐positive CTCs and 42% of patients with a HER2‐positive tumor had exclusively HER2‐negative CTCs). This evidence concerns the gene ERBB2 and neoplasm.