RT Journal Article SR Electronic T1 Frequent loss of SMAD4/DPC4 protein in colorectal cancers JF Molecular Pathology JO Mol Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 385 OP 388 DO 10.1136/mp.55.6.385 VO 55 IS 6 A1 R Salovaara A1 S Roth A1 A Loukola A1 V Launonen A1 P Sistonen A1 E Avizienyte A1 P Kristo A1 H Järvinen A1 S Souchelnytskyi A1 M Sarlomo-Rikala A1 L A Aaltonen YR 2002 UL http://mp.bmj.com/content/55/6/385.abstract AB 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.