In addition to the HIST2H3C and ACVR1 mutations, which were found in all parts of the specimen, we observed the acquisition of a KRASG12A mutation, not found in the diagnostic biopsy specimen, at high frequency in the main body of the tumor in the inferior left pons and, to a lesser extent, in the right pons and superior specimens (Fig. 5E). Here, ACVR1 is linked to neoplasm.