PIK3R1 and neoplasm: We screened 145 UCs for sequence mutations in a total of 16 genes, FGFR3, PIK3CA, PIK3R1, PTEN, AKT1, KRAS, HRAS, NRAS, BRAF, ARAF, RAF1, TSC1, TSC2, APC, CTNNB1, and TP53. In Figure 1 the results are summarized and the cases are grouped according to tumor grade.