title: Low Frequency Loss of Heterozygosity in the BRCA1 Region in Japanese Sporadic Breast Cancer.
abstract: To investigate the possible involvement of the BRCA1 gene in Japanese sporadic breast cancer we have analyzed loss of heterozygosity (LOH) at the BRCA1 region (17q12-q22) in 101 sporadic breast cancers using 5 microsatellite markers, such as D17S250, D17S846, D17S855, D17S579, and NME1. The frequency of LOH in each markers was 14.9%(11/74), 11.9 %(8/67),14.3%(12/84),5.3%(4/75), and13.3%(9/68),respectively. The incidence of LOH in at least one of 5 markers was 23.8%(24/101). The LOH at the BRCA1 region did not significantly correlate with clinicopathologic factors. Despite using a microdissection method, the LOH frequency in our series was relatively lower than other reports, especially in Western countries. We suggest that the BRCA1 gene might play only a limited role as a tumor suppressor gene in the majority of Japanese sporadic breast cancers.
authors.affiliation: Second Department of Surgery, Nagoya City University Medical School, 1 Kawasumi, Mizuho-ku, Nagoya 467, Japan.
authors.initials: T
authors.lastname: Yamashita
authors.initials: H
authors.lastname: Iwase
authors.initials: i
authors.lastname: Yamashita
authors.initials: H
authors.lastname: Iwata
authors.initials: K
authors.lastname: Ito
authors.initials: T
authors.lastname: Toyama
authors.initials: Y
authors.lastname: Hara
authors.initials: S
authors.lastname: Kobayashi