Clear link between breast cancer in mothers and tumours in children, claims study

Brussels, 24 Sep 2003

Mothers of children suffering from certain types of cancer have an increased risk of developing breast cancer, according to the results of a study presented on 24 September at the European cancer conference in Copenhagen, Denmark.

Dong Pang, an epidemiologist with the UK paediatric and familial cancer research group, and his colleague Julian Birch, studied the mothers of over 2,500 children below the age of 15, who had developed skin, brain and other types of solid tumours between 1954 and 1996. A total 95 cases of breast cancer were found - a third more than predicted - and scientists noticed that the risk of breast cancer appeared to increase if the child with cancer was diagnosed at an early age or if the affected child was a boy.

Dr Pang told delegates at the conference that the increased risk of breast cancer might be due to some form of mother-foetal interaction during pregnancy, and that the hormone, oestrogen might also play a role in the development of the cancer.

'We know that germline mutations in certain genes, particularly the tumour suppressor gene, p53, greatly increase the risk of both breast cancer in young women and certain tumours in children,' explained Dr Pang.

'The foetus itself is actively involved in the production and regulation of oestrogen, a hormone that is an established risk factor for breast cancer. We think that a combination of disruption of the normal role of p53 in cell cycle control and hormonal disruption during pregnancy contributes to the development of breast cancer in the mother and cancer in the child,' he added.

This is the first study to use such a large and comprehensive data set to show a clear link between breast cancer in mothers and solid tumours in children. Dr Pang is hopeful that the results of his group's study will contribute to a better understanding of how and when the process of carcinogenesis is initiated.

'The present study suggests that a crucial period for the development of both breast cancer in mothers and certain cancers in children is during pregnancy. Further research incorporating molecular biological studies will help to clarify this issue,' he surmised.

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