Minimizing false negatives in electron microscope searches for virus or other specific features of cancer cells

Electron microscopic searches for virus particles and other specific features of cancer cells involve exceptionally poor sampling statistics. It is probable that most searches conducted in the past were of limited value in establishing whether such viruses or special features are associated with one or more tumor types. On the other hand, in a few cases, the electron microscope has provided the first, or even the only, evidence of virus particles. A radical change in the way the electron microscope is applied to this problem is suggested whereby a high-voltage microscope is used to examine thicker sections and an image-processing arrangement is used to focus and select images and to search the images for virus particles. It is suggested that it is important to distinguish virus producers amongst oncogenic viral genome carriers since these may be in a more advanced state of tumor induction and may be capable of transmitting the virus to others.