Microsatellite instability in breast cancers with special reference to patients' age and bilaterality.

We examined breast cancers from 67 female patients to ascertain the possible correlation between RER or LOH status, age and bilaterality using eight microsatellite markers on chromosomes 2p, 3p, 16q, 17p and 17q. The frequencies of RER in young patients (25-35 years old), patients with double primary disease (43-77 years old) and patients with contralateral metastases (46-72 years old) were 35%, 63%, and 80%, respectively, while that in elderly patients (60-81 years old) was 0%. In contrast, there were no statistically significant differences in the frequency of LOH between these groups. Our results suggest that RER might play an important role in the occurrence of breast cancer at a younger age and in bilateral breast cancer.