REST and Familial prostate cancer: While LSD1 and EHMTs are known subunits of the REST repressor complex, involved in silencing gene transcription by demethylating and methylating their canonical histone targets (H3K4me1,2 and H3K9; ref. 20), studies from us and other groups have shown that LSD1 can also act as an activator in prostate cancer cells through multiple mechanisms, including the demethylation of non-histone proteins like FOXA1 (8, 31).