Novel Molecular Markers of Malignancy in Histologically Normal and Benign Breast
Figure 9
Immunohistochemical expression of TOP2A protein. (a) Histologically normal breast tissue from a reduction mammoplasty (RM) case featuring lack of nuclear expression of TOP2A in the epithelial cells lining a normal TDLU. (b) Histologically normal breast tissue from a patient with synchronous breast cancer showing positive nuclear staining in 4-5% of the mammary epithelial cells-higher TOP2A expression than the HNB tissues from a reduction mammoplasty case illustrated in (a). (c-d) A larger proportion of epithelial cells are immunoreactive for nuclear TOP2A protein in ductal carcinoma in situ (DCIS) and in the invasive ductal carcinoma (IDC) infiltrating the mammary fat. These cases illustrate an obvious increase in TOP2A protein expression from the lowest risk specimen from a reduction mammoplasty case (a), to the higher-risk specimens (c) and (d) (IMPOX staining for TOP2A; original magnifications 200x).
