PIK3CA and breast cancer: Well-known BC-related genes, such as BRCA1 (IBC11, IBC16, and IBC21), BRCA2 (IBC7 and IBC11), PIK3CA (IBC22 and IBC23), and TP53 (IBC11, IBC12, IBC16, and IBC22) were covered by cnLOH in our samples.