ERBB2 and Bloom syndrome: To help to standardize protocols, the US FDA recently approved the VENTANA PATHWAY anti-HER2/neu (4B5) rabbit monoclonal primary antibody for the IHC assessment of HER2 expression as the first companion diagnostic test; therefore, it was tested and used in the DESTINY 04 trial in metastatic BS patients to identify and select only HER2-low cases [71].