PIK3CA and breast cancer: Approaches that have yielded promising data in preclinical models include the use of alkylating agents to eliminate non-cycling residual primary BRCA−/p53− breast cancer cells in vivo [351], inhibition of Src family kinases (SFK), Src and MEK1/2 signaling [223,352], treatment with BMP7 [211] and VCAM-1 and integrin α4 antibodies [219] to suppress metastatic breast cancer outgrowth, inhibition of ERK and p38 [119] and PI3K/Akt [98,119] to diminish dormant ER+ BC cell survival in vitro.