Doebele et. al. also found diverse mechanisms (even two different ones in one lung cancer patient's tumor) of acquired resistance to crizotinib: http://www.ncbi.nlm.nih.gov/pubmed/22235099 Also in the same issue of Science Translational Medicine where Katayama published (posted by ariadndndough in #msg-72153321), there is a good overview (I have the paper if you or anyone wants to read): http://www.ncbi.nlm.nih.gov/pubmed/22323827