Fumarate hydratase: (FH) was recently identified as the predisposing gene for a tumor predisposition syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC) (MIM 605839). In HLRCC, individuals with a germline heterozygous mutation in the FH gene typically develop benign leiomyomas of the skin and the uterus (fibroids, myomas). In a subset of the families, predisposition to renal cell carcinoma and uterine leiomyosarcoma occurs. Other malignancies including breast cancer have also been detected in patients with a germline FH mutation. To examine whether FH could be involved in predisposition to breast cancer, we analyzed germline FH mutations from 85 Finnish breast cancer patients. Most of the cases were selected based on positive family or personal history for malignancies associated with HLRCC. No mutations were found. These results show that FH is not a major predisposing gene for familial breast cancer.