PIK3CA and cancer: Enrichment for these pathways in our cohort of PTs was largely due to the high prevalence of alterations affecting bona fide cancer genes (e.g., TP53, RB1, EGFR, ERBB2, ERBB3, PIK3CA) in the malignant and borderline tumors, given that similar results were obtained for those when we repeated the analysis stratifying PTs by grade.