PIK3R1 and neoplasm: Comparative gene expression analysis of both tumors revealed outlier expression of FGFR1, a promising target in rhabdoid tumors deficient in SMARCB1 (INI1).21 Gene expression analysis of DIPG tumor TH02_0087_S01 with a loss-of-function mutation of PIK3R1 (OMIM 171833) activating the PI3K/AKT/mTOR pathway revealed overexpression of the JAK/STAT pathway.