PIK3CA and cancer: Interestingly, copy number loss was seen in 30 samples (97%) for FGFR2 and in 24 samples (77%) for HIF1AN. Overall, CNVs were observed for BCa-related genes (e.g., PIK3CA, ERBB2, TP53, FOXA1), other cancer-related genes (e.g., ROBO2, ELN, CELF4) and other notable genes (e.g., DPP7, CYP26A1).