Even though additional studies of dural- and non-dural-based solitary fibrous tumors have shown consistent association between mitotic rate and fusion variant, with tumors harboring NAB2 exon 4–STAT6 exon 2/3 fusions consistently exhibiting lower mitotic rates than those with NAB2 exon 6–STAT6 exon 16/17, no further relationship between fusion variant and disease-free survival has been reported [1, 3, 6, 12, 18, 21]. This evidence concerns the gene STAT6 and solitary fibrous tumor.