Immunohistochemical study of ras and myc oncoproteins in apocrine breast lesions with and without papillomatosis.

We have previously employed different immunohistochemical procedures for the study of breast disease in the human. The use of the monoclonal antibodies (M. Abs) against protein products of the ras and c-myc oncogenes has shown that the respective oncoproteins are expressed not only in the cancer cases but also in the majority of complex cystic diseases (C.C.D.). The term C.C.D. is used when cystic disease is associated with epithelial hyperplasia and cellular atypia but without malignant transformation. Additionally, the degree of staining intensity is increasing when the latter is associated with papillary apocrine metaplasia, which is included in the group of epithelial hyperplasias. In the present study we examined 50 cases of C.D. 20 of which were present in infiltrating duct carcinomas of non otherwise specified (NOS) type and the remaining 30 concerned benign biopsy material. We divided C.D. into simple (S.C.D.) and complex (C.C.D.) and we focused our interest on the presence or absence of papillary hyperplasia in apocrine metaplastic lesions. The whole material (50 cases) was examined immunohistochemically for the c-myc p62 protein using the M.Ab. Myc 1-9E10, and 21 cases were also examined for the ras p21 protein using the M.Ab. Y13 259. Our results imply that the great majority of C.D. show elevated expression of both c-myc p62 and ras p21 when associated with apocrine metaplastic papillary proliferations. Our results suggest that the levels of the expression of ras and myc oncoproteins may serve as premalignant markers for the prevention of the disease.