Molecular and morphological evidence for type B retrovirus (oncornavirus) expression in human mammary carcinoma. An overview using scanning electron microscopy, immunoperoxidase staining, and transmission electron microscopy.

Approximately 45% of human mammary carcinoma cases express an antigen which cross reacts in formalin fixed tissues with antiserum prepared against the purified 52,000 molecular weight structural glycoprotein (gp52) of mouse mammary tumor virus (MMTV). Breast carcinoma immunoperoxidase marking is abolished by antiserum adsorption with MMTV. Adsorption with murine leukemia virus failed to block immunoperoxidase marking. No correlation was seen in the cases analyzed between gp52-like antigen expression and family history of mammary carcinoma, age, or pathological classification. The evidence linking an oncornaviral agent in human mammary carcinoma is reviewed with respect to the structure and biology of a known etiological agent, MMTV, in murine mammary cancer. The potential role of SEM in amplifying the surface area available for analysis in malignant and premalignant human breast epithelia is considered.