He said it might be the case that the virus was found in these particular cancer cells simply because they provided favourable conditions for it.

BBC: vaccine

In these people, the proportion of cancer stem cells decreased from 10% before therapy to 7.5% after they were treated.

ECONOMIST: Cancer therapy

These mutant stem cells already have been found in breast cancer, two types of leukemia and multiple myeloma.

FORBES: Cancer Killer