by Greta Friar, Whitehead Institute for Biomedical Research Epithelial cancer cells (in white) and quasi-mesenchymal cancer cells (in green). Credit: Anushka Dongre/Whitehead Institute Cancer is at its most deadly when two things occur: the cancer cells metastasize, spreading to new sites in the body, and the cells become resistant to treatment. The epithelial-mesenchymal transition (EMT) is a...