Using a combination of immunohistochemical studies [cytokeratins 7 and 20, E-cadherin, beta-catenin, p53, MLH-1, MSH-2, MSH-6, and O6-methylguanine methyltransferase (MGMT)], DNA sequencing [beta-catenin, adenomatous polyposis coli (APC), p53, KRAS, and BRAF], and a polymerase chain reaction-based microsatellite instability assay; we assessed each case for abnormalities in the Wnt signaling and mitogen-activated protein kinase pathways and DNA repair mechanisms.
C0920269
Microsatellite Instability