PIK3CA and cancer: Mutual exclusivity analysis in data from cBioPortal Combined Studies (n = 179,290) and PanCancer Atlas Studies (n = 76,639) of TCGA19,20 showed that genomic alterations in NOS2 significantly co-occur with those of PIK3CA, PTEN, and AKT1 genes (all p < 0.001) in multiple cancer types (Fig. 2B, Supp.