PIK3CA and breast adenocarcinoma: Indeed, PIK3ca mutations appear to be able to induce basal-luminal, and luminal-basal transitions, and de-differentiation into a multipotent stem-like state.76, 77 It is important to note, however, that only a small fraction of the tumors resulting from PIK3ca mutations are mammary adenocarcinomas, and most are subtypes rarely observed in humans.