The study from Iceland shows that blood relatives, both women and men, have an increased risk of ovarian, endometrial, breast and prostate cancers, all cancers of the reproductive system.
It is established that female blood relatives of women with breast cancer are more at risk of the disease, known as familial breast cancer, but less is known about links with other cancers.
The most striking finding is the raised risk among male relations of the breast cancer women for cancer of the prostate. However, in women who developed breast cancer before the menopause, under the age of 45, the raised risk of both prostate and breast cancer in relatives was not seen.
Hrafn Tulinius, Professor of Preventive Medicine at the Icelandic Cancer Registry in Reykjavik, said: 'A case-control study based on data from an American hospital found the same. That is, eight cases of prostate cancer were found among relatives of women with breast cancer - six fathers, one uncle and one brother. The risk relation is probably based on genes which act by increasing the risk for cancers at these sites.'
In two families with an unusually high incidence of prostate and breast cancer researchers found the same genetic pattern on a chromosome. They say the study, published in tomorrow's British Medical Journal, adds weight to arguments for genetic inheritance as an important risk factor for cancers, but a common environment may also play some part.
The pedigrees of 947 women with breast cancer were studied. Of the 29,725 people that this covered, 1,539 had breast cancer, 467 had prostate cancer, 135 had ovarian cancer and 105 endometrial cancer, of the lining of the womb.Reuse content