Erratum: Synergistic drug combinations tend to improve therapeutically relevant selectivity

Nat. Biotechnol. 7, 659–666 (2009); published online 5 July 2009; corrected after print 8 July 2009 In the version of this article initially published, in the legend of Figure 5b, line 2, “stress” is followed by a period. The period should be a comma, so that the sentence reads, “In response to stress, lymphoctyes.