Microsatellite instability analysis of sinonasal carcinomas

Intestinal-type sinonasal adenocarcinoma (ITAC) and squamous cell carcinoma of the nasal cavity (SCCNC) are histopathologically but not etiologically similar to colorectal adenocarcinoma or to laryngeal squamous cell carcinoma, respectively. Microsatellite instability (MSI) is involved in both tumors. The aim of this study was to investigate a possible role for MSI in the pathogenesis of two types of nasal carcinoma. DNA obtained from frozen tumor samples of 41 ITACs and 24 SCCNCs was analyzed for shifts in five mononucleotide microsatellite loci by multiplex PCR. The allelic patterns of one ITAC (2%) and five SCCNCs (21%) revealed an allelic shift for at least one of the five loci, indicating microsatellite instability. MSI may be involved in squamous cell carcinoma, but not in adenocarcinoma of the nasal cavities.