Microsatellite instability in thyroid papillary carcinoma and multinodularhyperplasia

Microsatellite instability (MSI) is a molecular landmark of mutations in DN A mismatch repair genes. The impaired efficiency of DNA repair mechanisms p romotes carcinogenesis as well as contributes to tumour progression. Until now, only few studies on MSI in thyroid tumours have been published. Theref ore, the aim of the present study was to investigate MSI as a possible char acteristic feature of thyroid tumours. The analysis of 12 thyroid papillary carcinomas and 17 multinodular hyperplasias at 13 microsatellite loci show ed MSI and loss of heterozygosity (LOH) in both types of lesion, with more alterations noted in the papillary thyroid carcinomas tin 65%) than in mult inodular hyperplasia (in 35%). In carcinomas, LOH occurred more frequently than MSI, while in multinodular hyperplasia the LOH/MSI ratio is almost equ al. Copyright(C) 2000S.KargerAG,Basel.