Assessment of microsatellite instability in head and neck cancer using consensus markers

Head and neck cancer is the sixth most common cancer in the world and one of the most lethal cancers. Microsatellite instability is an important characteristic of tumor cells and is observed both in presence and absence of mismatch repair gene mutations. The importance of microsatellite instability in head and neck cancer is not well established due to the lack of a consensus panel and selection of different markers, criteria and methodological variances. The main objective of this study was to investigate the performance of a consensus panel of microsatellite repeats by automated fragment analysis. Matched tumor and normal tissue samples from 99 patients were analyzed using five mononucleotide markers. Following PCR the amplified fragments were analyzed by capillary electrophoresis on an ABI 310 genetic analyzer. Microsatellite instability was observed in 26 patients. In 17 patients instability was detected at multiple loci. NR21 and BAT25 were the most frequently altered targets. These two mononucleotide markers could detect all samples displaying high-instability. In this study we describe a standardized fluorescent multiplex PCR combined with computerized analysis, which allows rapid and accurate analysis of a high number of samples and obviates the need to compare tumors with matching normal tissue.