PIK3CA and breast neoplasm: Given, these significant differential effects of oncogenes and cell type on breast tumor pathogenesis, in the present study we investigated the effect of overexpression of mutant PIK3CA (H1047R) in combination with mRas (Q61L) and mp53(R249S) on oncogenesis of stem/progenitor K5+/K19- and K5+/K19+ cells.