Many child tumours indicate increased maternal breast cancer risk

23 Jan 2008
Scientists at the University of Manchester have found links between many types of childhood cancer and increased breast cancer risk in the mother.

Although a previous study found high risk of breast cancer in mothers of children with soft tissue sarcomas, breast cancer risks in mothers of other childhood cancers remain largely unknown and the reasons for the links are not fully understood.

The study, published in ecancermedicalscience, explored the subject by varying the type of childhood solid cancer, found that for other cancers such as skin and cancer of the central nervous system, the established relationship stood.

The research reviewed the long term incidence of breast cancer in mothers of 2668 children with solid tumours included in the Manchester Children’s Tumour Registry, 1954-1996. The subjects were traced and followed up to the 31st of December 2000 using the UK National Health Service Central Register.

The number of observed cases was compared to the number of expected (normal) cases for women of the age range covered in the UK.

The results showed that the excess risk of breast cancer among mothers of children with solid tumours is not uniform across all groups, but is associated with a small number of tumour types and patient characteristics.

Excesses of breast cancer were found most frequently in mothers of children with rhabdomyosarcoma (RMS) - a cancer of the connective tissues, in which the cancer cells are thought to arise from skeletal muscle progenitors. Solid tumours of the skin and central nervous system in the index child were also found to be stronger indicators of maternal breast cancer.

The study confirms and extends the previous findings of a temporal relationship between embryonal RMS in children and breast cancer in their mothers and points to pregnancy as the critical period, when mothers and children are physiologically linked.

The research team, led by Dr Dong Pang, suggest that the increased cancer risk relationships may be due to germline mutations to cancer associated genes, either inherited or new in the offspring. They hypothesise that these germline mutations might commonly target the p53 pathway affecting tissue remodelling in the foetal adrenal cortex, not just one single gene within that pathway. They infer that the pathway may be disrupted by a germline mutation within the TP53 gene itself, as well as other genes p14ARF, BRCA1 and BRCA2, etc.

It is thought that this mechanism may also be operating in mothers of children with other types of cancers.

Read the full article here.