The qPCR and the western blot analysis results revealed that NUPR1 positively regulates the expression of the epigenetic regulator HDAC5, the anti-apoptotic molecule BIRC5, and the mitogenic receptor ERBB2 in MCF7-TamC3 and the ERBB2-enriched subtype like SK-BR-3 breast cancer cells. Here, HDAC5 is linked to breast cancer.