MSH3 and neoplasm: In contrast, MSH3-deficient tumours are characterised by high microsatellite instability (MSI) of di- and tetranucleotide repeats (the latter phenomenon is termed Elevated Microsatellite Alterations at Selected Tetranucleotide repeats; EMAST), whereas the MMR deficiency observed in Lynch syndrome-associated tumours tends to comprise high MSI at loci containing mono- and dinucleotide repeats.