Tian et al. (2017) recently discovered that VPA and hydroxyurea (a ribonucleotide reductase inhibitor) can limit the proliferation of MCF-7 BC cells synergistically by inhibiting RPA2 and increasing the Rad51-mediated homologous recombination DNA repair pathway. By suppressing the activity of HDAC1 and modifying the methylation state of H19 by induction of the enzyme DNA methyltransferase 1 (DNMT1) expression, Hao et al. (2017) found that VPA may induce death in A549 BC cells and reduce the production of the H19 oncogene. Here, DNMT1 is linked to breast cancer.