TY - JOUR T1 - Frequent loss of SMAD4/DPC4 protein in colorectal cancers JF - Gut JO - Gut SP - 56 LP - 59 DO - 10.1136/gut.51.1.56 VL - 51 IS - 1 AU - R Salovaara AU - S Roth AU - A Loukola AU - V Launonen AU - P Sistonen AU - E Avizienyte AU - P Kristo AU - H Järvinen AU - S Souchelnytskyi AU - M Sarlomo-Rikala AU - L A Aaltonen Y1 - 2002/07/01 UR - http://gut.bmj.com/content/51/1/56.abstract N2 - Background and aims: Loss of DNA sequences from chromosome 18q21 is a major genetic change in colorectal tumorigenesis. Multiple genes have been identified in this area. One of these, DPC4 (deleted in pancreatic cancer 4, also known as SMAD4), is mutated in a minor subset of colorectal carcinomas as well as in germlines of humans predisposed to colon tumours. Patients and methods: The involvement of SMAD4 in sporadic colorectal neoplasia was evaluated by immunohistochemistry in 53 unselected cases and 27 cases displaying microsatellite instability. Results: SMAD4 expression was absent in 20 of 53 (38%) unselected colorectal carcinomas, and reduced in another 15 (28%) cases. However, 26 of 27 cancers displaying microsatellite instability and TGF-βIIR mutations were positive for SMAD4 immunostaining. Conclusions: Loss of SMAD4 expression may play a more prominent role in colon cancer than anticipated based on genetic evidence, but not in mutator phenotype tumours. ER -