Metastatic Nodules of Human Breast Cancer Following Prolonged Estrogen Therapy: A Model for Ultrastructural Study

Abstract

Most of the models in the studies of breast cancer use murine tissues. Data from these studies, based on the “milk factor” theory, promoted the discovery of the mammary tumor virus (MTV). Electron microscopy of murine tissues, both in vivo and in vitro, and fractions of milk from tumor bearing mice confirmed and described the MTV entity at the ultrastructural level. Application of information obtained from studies of the murine model to the human problem has been difficult in the past for technological reasons, or more importantly, a lack of consistent or controlled sources of human materials. With technological improvements, studies of human material of a more controlled nature, based on population statistics, have been accomplished. The source of tissues studied in this presentation are recurring metastatic nodules from patients who had been treated for breast cancer. Easily accessible nodules from both estrogen treated and untreated patients were compared in this study. No differences were found. Recent reports of virus particles or virus-like particles, particularly of the B type variety, have promoted the search for them in human tissues.