Furthermore, the HDAC1 immunohistochemical staining showed nuclear expression of HDAC1 in all of the stages of squamous carcinogenesis, including PHP, squamous dysplasia and SCC, and adenocarcinogenesis, including BM and ADC, however, this was not observed in the normal squamous epithelium (Fig. 2). The gene discussed is HDAC1; the disease is AIDS dementia complex.