ERBB2 and metastatic neoplasm: In particular, we explored genomic differences between sites of metastatic disease and made the following observations: (a) All intrinsic molecular subtypes are identified within IHC groups; (b) HER2‐low disease is identified in all metastatic sites; (c) intrinsic molecular subtypes determined in the metastatic site are associated with OS regardless of where biopsy was performed; (d) lung and pleural metastases have the highest expression of immune genes, while brain and liver have the lowest; and (e) the expression of individual genes is organ‐specific and is associated with OS.