Figure 1 Assessment of microsatellite instability in a mononucleotide repeat. (A) Microsatellite stable colorectal carcinoma. (B) Tumour no 674‐61: biphasic shape of the polymerase chain reaction product. Both peaks lie in the window (vertically plotted lines) defining microsatellite stability according to Suraweera et al.6 (C) Microsatellite instable colorectal carcinoma (repeat NR‐24; medium length of NR‐24 in our study was 131 bp).