ACTA1 and invasive lobular breast carcinoma: Indeed, the presence of resident CD34+SFCs/TCs (there are no αSMA+ stromal cells) in the normal breast and of stromal cells that only express CD34, coexpress CD34 and αSMA, and only αSMA in the tumours strongly supports the origin in CD34+SCs/TCs resident in the normal breast of αSMA+ stromal cells in invasive lobular carcinoma.