In addition, though the prevalence of BRCA1 and BRCA2 mutations is high, there is a low frequency of breast and ovarian cancers among family members, said lead author Bruce Haffty, M.D., professor of therapeutic radiology at Yale School of Medicine.
"Typically you see a lot of breast and ovarian cancers among families with the BRCA1 and BRCA2 mutations," Haffty said. "The majority of breast cancer patients found to have BRCA1 or BRCA2 also reveal a family history of breast and/or ovarian cancer in at least one first degree relative."
Haffty analyzed a sample of 60 breast cancer patients 40 or younger treated at a hospital in Seoul, Korea. The average age at which breast cancer is diagnosed in women in the United States is 50-60: in Korea, the average age is 40-50.
Nine patients of the 60 patients had the genetic mutation in one of the two genes and two patients had mutations in both BRCA1 and BRCA2 genes. Only two of the patients had a family history of breast or ovarian cancer.
"These data suggest that there may be different genetic and etiologic factors affecting transmission and penetrance of the BRCA genes in Korean patients with breast cancer who are diagnosed at a young age," Haffty said. "One possible environmental effect might be attributed to the Asian diet or caloric intake."
He plans to follow up with a larger study funded by the Susan Komen Foundation that will include an additional 50 women. The study also will include a large number of African-American women because the onset of breast cancer is younger for these women, too.
Co-authors include Allen Bale and Darryl Carter from Yale, and Doo Ho Choi and Min Hyuk Lee from Korea.
Citation: Journal of Clinical Oncology, Vol. 22: 1638-1645, May 1, 2004.
Journal of Clinical Oncology