Examples are expression of hormone receptors in cancers of prostate, ovary and breast [10, 11]; mutations affecting metabolism (isocitrate dehydrogenase mutations [p.IDH1-R132H] in glioma and acute myeloid leukemia [12]); and mutations affecting the PI3K and MAPK pathway (PIK3CA, p.KRAS-G12/G13 mutations in adenocarcinomas [13], p.BRAF-V600E in melanoma [14]). The gene discussed is PIK3CA; the disease is glioma.