A Phase 1 Cellular Immunotherapy Study of Intraventricularly Administered Autologous HER2‐Targeted Chimeric Antigen Receptor (HER2‐CAR) T Cells in Patients With Brain and/or Leptomeningeal Metastases From HER2 Positive Cancers. This evidence concerns the gene ERBB2 and leptomeningeal metastasis.