Genetic instability in microsatellite sequences in prostate-cancer.

Mutations in microsatellite sequences, especially expansion in the number of di- and trinucleotide repeats, have been implicated as the cause of several heritable disorders, including fragile X syndrome and myotonic dystrophy. We examined the possibility that a similar mutation mechanism might be involved in human prostate cancer. Our findings indicate that mutations in microsatellite sequences are frequent in prostate cancer. Six of thirty patients (20%) had an allele gain in at least one microsatellite sequence; three patients (10%) had allele gains in multiple loci. The new alleles were present in the tumor DNA, but not in the normal DNA. Although we did not detect mutations in the androgen receptor microsatellite sequences, it is likely that this type of mutation affects other genes important in prostate cancer, thereby promoting tumor development and progression.