TP53 and breast cancer: Because we have observed up-regulation of p53 at the transcriptional level with the combination of hydralazine and valproate in tumors of patients with breast cancer [25], and in addition, histone deacetylase inhibitors acetylate non-histone transcription regulatory proteins [26], we wanted to analyze whether these epigenetic drugs would induce changes at p53, which is a key player in HPV carcinogenesis.