PIK3CA and cancer: Of interest, besides identifying well-known cancer drivers, e.g., TP53, PIK3CA, PTEN, KRAS, and CDKN2A) as SGA-FIs, TCI also designated as SGA-FIs some very frequently altered genes, e.g., TTN, CSMD3, MUC16, LRP1B, and ZFHX4, whose roles in cancer development remain controversial.