Letter | Published:

The molecular evolution of acquired resistance to targeted EGFR blockade in colorectal cancers

Nature volume 486, pages 537540 (28 June 2012) | Download Citation


Colorectal tumours that are wild type for KRAS are often sensitive to EGFR blockade, but almost always develop resistance within several months of initiating therapy1,2. The mechanisms underlying this acquired resistance to anti-EGFR antibodies are largely unknown. This situation is in marked contrast to that of small-molecule targeted agents, such as inhibitors of ABL, EGFR, BRAF and MEK, in which mutations in the genes encoding the protein targets render the tumours resistant to the effects of the drugs3,4,5,6. The simplest hypothesis to account for the development of resistance to EGFR blockade is that rare cells with KRAS mutations pre-exist at low levels in tumours with ostensibly wild-type KRAS genes. Although this hypothesis would seem readily testable, there is no evidence in pre-clinical models to support it, nor is there data from patients. To test this hypothesis, we determined whether mutant KRAS DNA could be detected in the circulation of 28 patients receiving monotherapy with panitumumab, a therapeutic anti-EGFR antibody. We found that 9 out of 24 (38%) patients whose tumours were initially KRAS wild type developed detectable mutations in KRAS in their sera, three of which developed multiple different KRAS mutations. The appearance of these mutations was very consistent, generally occurring between 5 and 6 months following treatment. Mathematical modelling indicated that the mutations were present in expanded subclones before the initiation of panitumumab treatment. These results suggest that the emergence of KRAS mutations is a mediator of acquired resistance to EGFR blockade and that these mutations can be detected in a non-invasive manner. They explain why solid tumours develop resistance to targeted therapies in a highly reproducible fashion.

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The authors thank J. Schaeffer, J. Ptak, N. Silliman and L. Dobbyn for technical assistance and M. Ekdahl for operational assistance. This work was supported by The Virginia and D. K. Ludwig Fund for Cancer Research, the National Colorectal Cancer Research Alliance, NIH grants CA129825, CA43460, CA57345, CA62924, CA095103, and R01GM078986, NCI contract N01-CN-43309, ERC Start grant (279307: Graph Games), FWF NFN Grant No S11407-N23 (Rise), and the John Templeton Foundation. Simulations were performed on the Orchestra cluster supported by the Harvard Medical School Research Information Technology Group.

Author information


  1. Ludwig Center for Cancer Genetics and Therapeutics and Howard Hughes Medical Institute at Johns Hopkins Kimmel Cancer Center, Baltimore, Maryland 21287, USA

    • Luis A. Diaz Jr
    • , Jian Wu
    • , Isaac Kinde
    • , Kenneth W. Kinzler
    •  & Bert Vogelstein
  2. Swim Across America Laboratory at Johns Hopkins, Baltimore, Maryland 21287, USA

    • Luis A. Diaz Jr
  3. Amgen Inc., Thousand Oaks, California 91320, USA

    • Richard T. Williams
    •  & Kelly S. Oliner
  4. State Key Laboratory of Cancer Biology, Cell Engineering Research Center & Department of Cell Biology, The Fourth Military Medical University, Xi’an 710032, China

    • Jian Wu
  5. Division of Hematology/Oncology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA

    • J. Randolph Hecht
  6. Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA

    • Jordan Berlin
  7. Program for Evolutionary Dynamics, Harvard University, Cambridge, Massachusetts 02138, USA

    • Benjamin Allen
    • , Ivana Bozic
    • , Johannes G. Reiter
    •  & Martin A. Nowak
  8. IST Austria (Institute of Science and Technology Austria), Klosterneuburg 3400, Austria

    • Johannes G. Reiter


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L.A.D., K.S.O. and B.V. designed experiments, analysed data and wrote the paper. B.V., I.K. and J.W. performed experiments, analysed data and provided input to the manuscript. R.T.W., J.B. and J.R.H. provided critical materials, reagents, analysed data and provided input to the manuscript. B.A., I.B., J.G.R. and M.A.N. analysed data, performed the mathematical modelling and provided input to the manuscript.

Competing interests

L.A.D., K.W.K. and B.V. are Founding Scientific Advisors of Personal Genome Diagnostics, Inc., a company focused on the identification of genetic alterations in human cancer for diagnostic and therapeutic purposes. L.A.D., K.W.K. and B.V. are members of the Scientific Advisory Board of Inostics, a company that is developing technologies for the molecular diagnosis of cancer. L.A.D., B.V. and K.W.K. also own stock in Inostics. K.W.K. and B.V. are entitled to a share of the royalties received by the University on sales of products related to BEAMing. Spouse of L.A.D. is an employee of Amgen. The terms of these arrangements are being managed by Johns Hopkins University in accordance with their conflict of interest policies.

Corresponding authors

Correspondence to Luis A. Diaz Jr or Kelly S. Oliner.

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    Supplementary Information

    This file contains Supplementary Table 1-6, Supplementary Figures 1-3 and a Supplementary Appendix, which contains Supplementary Text and Data 1-4, Supplementary Figure 1 and additional references.

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