Immunophenotype of intraductal carcinoma.

Mammography and breast-conserving therapy have focused attention on the classification of intraductal carcinoma (IDC) and emphasized the prognostic importance of comedo versus noncomedo variants. We used histochemical markers to define the immunophenotype of 43 IDCs with respect to comedo versus noncomedo status and patterns of angiogenesis. Reactions in comedo carcinomas were significantly negative for estrogen receptor and progesterone receptor, and positive for p53 and HER-2/neu more often than the noncomedo variant. All seven IDCs associated with Paget's disease showed positive reactions for HER-2/neu. Basement membrane immunoreactivity for type IV collagen and laminin was discontinuous in most examples of IDC regardless of type, with a trend toward more intense staining in comedo than in noncomedo carcinomas. Periductal angiogenesis was not significantly related to the type of IDC but was more pronounced with comedo carcinomas. These observations indicate that there are immunophenotypic correlates to the current structural classification of IDC. The immunophenotype of IDC is helpful in subclassifying an IDC and could prove useful as a prognostic indicator for local control in patients treated by breast-conserving therapy.