The official blog for Production baobab, a voice actor agency, announced that Tomoko Kawakami, legendary voice actress of Revolutionary Girl Utena, passed away on June 9th.
Since August 2008 the actress had been in the hospital due to ovarian cancer, which required surgery. After her surgery, most of her ongoing roles were replaced by other actresses, though Kawakami still did a little voice work during the time.
Debuting in 1994 as a boy in the television anime series Metal Fighter Miku, Kawakami's first regular appearance was as Chiriko in Fushigi Yuugi in 1995. She would later go on to voice the famous Utena Tenjou from Revolutionary Girl Utena, Rosette Christopher from Chrono Crusade, Hikaru Shindo from Hikaru no Go and Soifon from Bleach.
Kawakami was 40 years old when she passed away.
Sources: 1, 2