Forty-seven latent prostate cancers obtained from 46 Japanese men were
examined for microsatellite instability (MSI). This study with examin
ation at 23 microsatellite loci revealed replication error (RER) in 11
of the 47 cases (23%), 4 of them showing RER with 2 loci that was def
ined as MSI. Histological grade was significantly associated with RER;
9 of the 11 RER positive cases were of infiltrative type, and the 4 o
f them exhibiting MSI were all poorly differentiated. While the freque
ncy of MSI in latent prostate cancer was lower than in clinical cases,
it was found in the more aggressive lesions thought most likely to de
velop into clinical cancers. (C) 1996 Wiley-Liss, Inc.