ERβ signaling has been associated with a tumor-inhibitory effect in PC through both the classical (ERβ and estrogen-response element complex) and non-classical pathways (ERβ, Krüppel-like zinc finger transcription factor 5, and adenosine 3′,5′-monophosphate response element-binding protein-binding protein complex) [30]. Here, ESR2 is linked to pachyonychia congenita.