Microsatellite instability (MSI) increases with age in normal somatic cells

Small pool PCR (SP-PCR) is a sensitive method for the detection and quantification of microsatellite instability (MSI) in somatic cells. Here we propose that mutant microsatellite fragments accumulate with age in normal somatic cells and tha: this increase in MSI can be quantified by SP-PCR. MSI at 6 microsatellite loci was determined by SP-PCR in PBL DNA from 17 "normal" blood bank donors. These individuals varied in age from 20 to 67 y/o. MSI phenotypes were plotted against age in a regression analysed. A positive slope indicated a correlation between age and MSI phenotype (p = 0.0006). The mean weighted average mutant frequencies across all loci for all individuals in the age groups (0.009 for 20-30 y/o; 0.019 for 35-50 y/o; 0.034 for 60-70 y/o) were also significantly different rom each other (p < 0.01). A baseline for increases of MSI with age in human somatic cells was therefore begun and the effectiveness of SP-PCR to evaluate low, but significant, levels of MSI, established. (c) 2005 Elsevier Ireland Ltd. All rights reserved.