TGFBR2 and hereditary nonpolyposis colon cancer: In another Mendelian bowel tumour syndrome, hereditary nonpolyposis colon cancer (HNPCC), the effects of DNA mismatch repair (MMR) deficiency can be detected somatically through the presence of microsatellite instability (MSI) and frameshift mutations in short repeats within genes such as BAX and TGFBR2 (Woodford-Richens et al, 2001).