DNA screening for breast/ovarian cancer susceptibility based on linked markers. A family study

Linkage to chromosome 17q has been identified in hereditary breast cancer and hereditary breast/ovarian cancer syndrome. A hereditary breast/ovarian cancer syndrome kindred was identified that yielded a highly significant lod score (4.20) when 17q markers were studied, enabling us to identify those who probably carried the cancer-associated gene among the high-risk members of the family.

High-risk members of the hereditary breast/ovarian cancer syndrome kindred were offered counselling on the basis of 17q markers. Family members responding positively received one-to-one genetic counseling in a structured setting. Subjects were educated before disclosure, and the immediate impact of this information was assessed after disclosure.

We provided genetic counseling on the basis of linkage findings to 32 relatives (four men and 28 women). Women who were told they were linkage positive expressed an increased motivation for surveillance and prophylactic surgery. Most women who were told they were linkage negative indicated that they would not proceed with prophylactic surgery but would continue careful surveillance. To date, there has been no evidence of serious emotional disturbances resulting from this disclosure. We believe that this experience can be used by cancer geneticists and physicians in developing protocols for genetic counseling in cancer-associated hereditary disorders.

Physicians must understand current developments in cancer genetics and linkage so that they can be applied to genetic counseling and treatment of high-risk patients.