A Small Virus-Like Particle Observed in Human Breast Cancer by Means of Electron Microscopy<xref ref-type="fn" rid="FN2">2</xref>

Abstract

A small virus-like particle was observed by means of thinsection electron microscopy in 9 of 24 (37%) human breast cancer biopsies, in density-gradient purified mille specimens from 4 of 7 (57%) breast cancer patients, and in 7 of 43 (16%) normal women examined to date. The ultrastructural morphology, which reveals a particle of approximately 30 mμ in diameter with an inner electron-dense nucleoid and a double outer membrane, appeared identical in all three materials.