text:  K8 PIK3CA H1047R basal GFP pos rep2 K8-creERT2/PIK3CA H1047R strain: mixed background FVB/CD-1; genotype/variation (animal): K8-creERT2/PIK3CA H1047R; treatment: activation of PIK3CA H1047R transgene expression by Tamoxifen injection; time: 4 wks post-Tamoxifen; cell type (mammary cell subpopulation): basal H1047R-expressing subset