SMAD4 and colorectal carcinoma: In a subset of 7 cases with prominent CSC-like transition zones, DNA sequencing revealed the mutation of frequencies of 14.3% for TP53 (1/7), 28.6% for SMAD4 (2/7), and 57.1% for APC (4/7), indicating a possible higher SMAD4 and lower TP53 mutation rate than unselected CRC cases [17].