PIK3CA and neoplasm: By comparing the genomic/molecular pattern in tumor and normal tissues, four distinct cancer subtypes were identified: (i) Epstein–Barr virus (EBV)-positive tumors, that show DNA hypermethylation, PIK3CA mutations, and PDL-1/2 amplification; (ii) tumors with microsatellite instability (MSI), showing high tumor mutational burden; (iii) genomically stable tumors (GS), characterized by an activated function of the Rho family of GTPases proteins; and (iv) tumors with chromosomal instability (CIN), which show aneuploidy and amplification of receptor tyrosine kinases [57].