Fetus can 'catch' mum's cancer

In rare circumstances, it is possible for cancer to be passed in the womb from mother to fetus, according to international researchers. A team of British and Japanese researchers, writing in the journal Proceedings of the National Academy of Sciences, report the case of a Japanese woman who developed acute lymphoblastic leukaemia (ALL) shortly after giving birth, and at 11 months, her daughter developed tumours in her cheek and fluid on her lungs.

The researchers examined the DNA of the child's tumours and found that the cells carried the same mutation as the mother's cancer cells, however the child's own DNA did not contain the mutation. Additionally, the child's cancer cells lacked genes related to immune system function which normally block any cancer cells which passes through the placental barrier during pregnancy. 'It appears that in this, and other cases of mother-to-offspring cancer, the maternal cancer cells did cross the placenta into the developing fetus and succeed in implanting because they were invisible to the immune system', said lead researcher Professor Mel Greaves, from the Institute of Cancer Research in the UK.

Genetic analysis showed that there was no DNA from the child's father in her cancer cells, ruling out the possibility that she inherited the disease at conception. Professor Peter Johnson, the chief clinician at charity Cancer Research UK, emphasised that this kind of case is very rare. There are records of only 17 similar cases worldwide, where cancer breaches the placental barrier and is able to grow in the fetus without being attacked by the immune system. 'This is really important research as it adds to the evidence that cancers need to evade the immune system before they can grow, giving hope that by alerting a patient's immune system to a cancer, we can develop new types of treatment', said Professor Johnson.