In multivariate Cox regression analysis, cytoplasmic HDAC3 was still an independent prognostic factor for the occurrence of brain metastasis in the breast cancer patients after correction for tumor size, ER, PR, and HER2 (Table 3); nuclear HDAC3 was not an independent prognostic factor in the multivariate analysis, which suggested that the influence of nuclear HDAC3 on brain metastasis in such patients was also possibly linked with other variables. Here, ERBB2 is linked to breast cancer.