The Van Nuys (VN) classification system for ductal carcinoma in situ (DCIS) of the breast is a simplified morphology-based system that uses the presence of nuclear pleomorphism and comedo-type necrosis to stratify DCIS lesions into 3 prognostic groups.
To determine if there is an underlying biological basis that correlates with the morphologic aspects of the VN classification system.
We evaluated the expression of markers implicated in the development of breast cancer (p53, ErbB2, and TAG-72) in DCIS classified with the VN system. Forty-five cases of pure DCIS were classified as 8 cases of VN1, 7 cases of VN2, and 30 cases of VN3. p53, ErbB2, and TAG-72 antigen expression was measured by immunohistologic means in each of the cases.
Nuclear accumulation of p53 was only observed in VN3 (30%). ErbB2 overexpression was found only in VN2 (14%) and VN3 (43%). TAG-72 expression was observed in all categories of lesions but was more frequent in VN2 (71%) and VN3 (70%) compared with VN1 (25%). It appears that overexpression of ErbB2 and p53 are features associated with the high-grade lesions.
The simplified VN classification system for DCIS has a clear underlying biological basis as evidenced by differential expression of tumor-associated antigens in each of the 3 morphologic categories. These differences may contribute to the differential clinical behavior of the separate groups.