A SCREENING FOR BRCA1 MUTATIONS IN BREAST AND BREAST-OVARIAN CANCER FAMILIES FROM THE STOCKHOLM REGION

To identify BRCA1 germ-line mutations in the breast and breast-ovarian cancer families in the Stockholm region, a total of 127 families were screened. DNA from 174 patients from these families were studied usin g various mutation screening techniques, followed by direct DNA sequen cing. Mutations were identified in 7 of 20 families with breast and ov arian cancer and in one family with ovarian cancer only, whereas only 1 family of 106 with breast cancer shelved a mutation. Thus, germ-line mutations in BRCA1 were found in one-third of the families with both breast and ovarian cancer, but in only 1% of the breast cancer familie s. The low frequency of germ-line mutations in the site-specific breas t cancer families means that other genes are likely to segregate in th ese families.