Scientists have found evidence that cancer cells can ‘sleep’, avoiding the effects of chemotherapy, and then ‘reawaken’ later. Researchers at the Institute of Cancer Research say this may explain why some cancers return, many years after they appear to have been cured. They analysed a patient whose leukaemia returned after 20 years in remission.
The findings may help scientists to root out these dormant cancer cells, wake them up and kill them. The study, published in the journal Leukemia, found that the cancer cells which ‘woke up’ in the patient after a period of two decades were similar to a group of cancer cells that pre-dated the original bout of the disease.
Blood and bone marrow samples were taken from the patient when he was diagnosed with a rare form of leukaemia at four years old and compared to samples taken when he relapsed aged 25.
Researchers identified a specific DNA mutation in cancer cells from both blood samples, in which two genes called BCR and ABL1 fuse together. They said this showed a common link between the original and the relapsing leukaemia.
But they also found many new genetic changes had occurred in the cancer cells when the patient relapsed. This implies that cancer cells had become dormant, resisted chemotherapy and then ‘woke up’ after many years of rest.