Resistance of BaF3-FPTase β mutants to lonafarnib. (A) Soft agar colony formation in the presence of varying lonafarnib concentrations. Colony formation is shown as a ratio of colonies formed in the presence of lonafarnib to colonies formed in diluent alone. t test: *P < .05; ♦P < .01. Error bars are standard errors. (B) Immunoblot of the HDJ2 biomarker. Prenylated (processed) versus unprenylated (unprocessed) HDJ2 can be discerned at varying lonafarnib concentrations. Mutations with P < .05 in the soft agar colony assay are highlighted. (C) Immunoblot of the I107V mutation identified in a patient sample, and not in the random mutagenesis.