FGFR4 and neoplasm: However, there was no difference in tumor volume for mice injected with the RMS772 FGFR4 WT or empty vector cell line when treated with or without ponatinib (Figure 5C and 5D), indicating that RMS tumors with activating FGFR4 mutations at their tyrosine kinase domain may be more sensitive to the inhibition of ponatinib in vivo.