Since seminal findings [6] and our own previous work [8] demonstrated that full-length ErbB-2 is present in the nuclear compartment of breast cancer cells, we also tested the mouse monoclonal 9G6 antibody directed against the ErbB-2 amino (N) terminus, which we previously found recognized NuclErbB-2 and MembErbB-2 by IF in breast cancer cells [8]. This evidence concerns the gene ERBB2 and breast cancer.