PIK3CA and neoplasm: In BCCuS-low group, the mutation frequency of PIK3CA, CDH1, MAP3K1 up-regulated, these genes have been reported as tumor suppressor in breast cancer (Figure 8A) (Jiang et al., 2014; Couch et al., 2017; Ge et al., 2017; Zacksenhaus et al., 2017; Xue et al., 2018; Wijshake et al., 2021).