Study of SMA expression among high and low grade ductal carcinoma in situ, revealed that there are no SMA positive myofibroblasts around DCIS-L (B) while around high grade DCIS, SMA positive myofibroblasts are identified (A). The opposite phenomenon is observed regarding CD34 expression upon stroma fibroblasts. It is shown that in high grade DCIS there is a dramatic decrease of CD34 positive fibroblasts (C) as opposed to the CD34 positive stroma fibroblasts of DCIS-L (D). CD 31 staining showing a high microvessel density of the stroma adjacent to a DCIS-H (E). Arrowheads showing CD 31 positively stained vessels. Magnification × 100.