Immunohistochemical analysis on biological markers in ductal carcinoma in situ of the breast

The increasing use of mammographic screening has led to an increased detection of ductal carcinoma in situ (DCIS) of the breast. The detailed biological characteristics of DCIS and a new classification of DCIS based on these characteristics are needed. Immunohistochemical studies were performed to assess the expression of c-erbB-2 (ErbB-2), estrogen receptor (ER), p53 and proliferative activity (Ki-67) in 65 patients with pure DCIS and 60 with invasive ductal carcinoma (IDC). We classified pure DCIS tumors using three classifications, the architectural, Nottingham, and Van Nuys classifications. ErbB-2, ER and p53 staining was positive in 34%, 66% and 21% of patients with DCIS, respectively, and 58%, 42% and 33% in patients with IDC, respectively. Ki-67 stained positively in 1.5% of patients with DCIS and 11.2% of patients with IDC. The comedo type showed a high rate of positive ErbB-2 and p53 staining. The cribriform and papillary types showed a high rate of positive ER staining. Under the Van Nuys classification, ErbB-2, p53 and Ki-67 expression were highest in the group with high nuclear grade and lowest in the group with non-high nuclear grade without necrosis. Although the biological markers of IDC tended to suggest aggressive behavior more so than those of DCIS, these differences were based on the histological sub-type, comedo or non-comedo. The Van Nuys classification best defined the subgroups of DCIS with a distinct expression pattern of biological markers, and the best candidates for breast-conserving surgery.