SKE48 Team E member Takatera Sana announces her graduation and leave SKE48 at the end of January 2018, she make the announcement on her official blog at 12 December 2017.
Takatera Sana is 1st generation of AKB48 group DRAFT member, she joined the group as AKB48 Group Draft Kaigi 2 finalist, and drafted into Team E in 2013
Original sources: Takatera Sana's blog