PIK3CA and neoplasm: The most common genetic marker associated with RGNT is the PIK3CA mutation.28,29,51,74,84,85  FGFR1 mutations have also been implicated in tumor pathogenesis51,84–86 as well as IDH1,40  KIAA1549/BRAF gene fusion,20  PPP1R1A,51 and RNF21. 51