Tragedy in stem cell research. Two studies (Nature 505; 641-647, 2014; Nature 505, 676-680, 2014) caused a great stir in the scientific world when it was reported that adult cells could be reprogrammed by simply incubating them in an acid medium. However, it was later shown that the method had defects, so both studies had to be retracted. As a result, their principal author, Yoshiki Sasai, became severely depressed, and committed suicide on 5 August 2014 (Nature Medicine 20; 975, 2014).