Editor,—The results presented in the article by Curran et al ((2000) Gut 46:200–204; OpenUrlAbstract/FREE Full Text) may have been different if the authors had classified DNA microsatellite instability status as stable (MSS), low (MSI-L) or high (MSI-H), as recommended by a National Cancer Institute sponsored workshop.1 Their “RER+” group included both MSI-H and MSI-L cancers. The finding of bandshifts in two of eight dinucleotide markers is not specific for MSI-H cancers and will pick up a proportion of MSI-L cases.2 ,3 Two of the three RER+ cancers with a K-ras mutation (study Nos 52 and 129) showed bandshifts at only two loci, …

Dr D T Croke. Email:dtcroke{at}rcsi.ie