Correction to: Nature https://doi.org/10.1038/nature14969 Published online 30 September 2015

In Extended Data Fig. 8 of this article, a micrograph shown in the left column (panel AZD) was inadvertently duplicated during figure preparation. The intended image was meant to show phospho-ERK (P-ERK) levels in a MAP2K1-mutant patient-derived xenograft (PDX) exposed to the MEK inhibitor AZD6244 (AZD). However, this image was accidentally overlaid with a micrograph from Extended Data Fig. 10 (left column, panel PAN), which displays P-ERK levels in an EGFR-mutant PDX exposed to panitumumab (PAN). A corrected version of Extended Data Fig. 8, now containing the appropriate image, is available as Supplementary Information alongside this amendment. The quantification, statistical analyses and overall conclusions of the study remain unchanged, as all analyses were performed using the correct underlying morphometric data. Due to the age of the article, the figure cannot be updated directly. This notice serves to correct the article.

Supplementary information is available in the online version of this amendment.