Enormous genetic variation may shield tumors from treatment

The most rigorous genetic sequencing ever carried out on a single tumor reveals far greater genetic diversity among cancer cells than anticipated, more than 100 million distinct mutations within the coding regions of its genes. The finding suggests that even microscopic tumors are likely to contain extremely high genetic diversity. With so much variation, even small tumors are likely to contain cells that may be able to resist standard post-surgical cancer treatment such as chemotherapy and radi...