PIK3CA and neoplasm: Subsequently, we used multinomial logistic regression to model high/low immunity based on combinations of Ras/ERK and PI3K/AKT signaling (Fig. 3A), and identified IGF1R, KRAS, MAPK1, PIK3CD, PIK3CG, and PIK3R5 combined expression as significant predictors of tumor immunity with an accuracy of 81% (Akaike information criterion [AIC] = 76.2; Supplementary Fig. S18).