Stereotactic surgery boosts accuracy when treating "hidden" brain tumors.

Accuracy When Treating "Hidden" Brain Tumors said. Breast cancer is a category describing several different kinds of tumors, and cancer may have many etiologies so there may be more than one virus at work, or none at all. "If there is a human breast cancer virus," said Levine, "it's obviously not all over the place. That's why we're concentrating on certain populations." Although Levine believes such a virus could be transmitted through milk, Sarkar said several factors argue against this idea. One is that breast cancer rates have increased while breast-feeding has declined. Another is the poor correlation between MMTV-like particles in breast milk and family history of breast cancer.