Microsatellite instability in sporadic human breast cancers

Human breast-cancer specimens from 100 patients were analyzed for microsatellite instability (referred to as replication error; RER) at 12 genomic loci on 7 chromosomes, and results were correlated with clinicopathologic characteristics. In 42 of 100 breast-cancer patients, we investigated whether RER was associated with the amplification of oncogenes and/or suppression of tumor-suppressor genes. Of the 100 patients, 8 (8%) were RER-positive at one or more chromosomal loci. The majority of RER-positive patients had early-stage disease with ER-positive tumors, suggesting that RER occurs early in breast tumorigenesis. However, no significant correlation was observed between RER and oncogenes or tumor-suppressor genes. Thus, the mechanism of RER in sporadic human breast cancer may be independent of the multi-step carcinogenesis caused by the alterations of oncogenes and tumor-suppressor genes. © 1996 Wiley-Liss, Inc.