Accounting for the impact of trisomy 8 or loss of heterozygosity involving chromosome 8p, the relative mutant allele frequencies of FGFR1 versus PIK3CA or PIK3R1 were approximately equivalent in 7 of the 9 tumors, indicating that these two events were both likely to have occurred early during tumor evolution and were present clonally throughout all tumor cells. This evidence concerns the gene PIK3R1 and neoplasm.