                    Qiaoli Zhao 1 , Nadine Kretschmer 2 , Rudolf Bauer 2 , and Thomas Efferth 1              ! "       #     $   Thomas Efferth, Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudingerweg 5, 55128, Mainz, Germany. Tel.: +492613123925751; Fax: +4926131223752; E2mail: efferth@uni2mainz.de  Shikonin; Naphthoquinone; Epidermal growth factor receptor; Drug resistance; Synergism, Tyrosine kinase inhibitor This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as an ‘Accepted Article’, doi: 10.1002/ijc.29483 This article is protected by copyright. All rights reserved.