SMAD6 and colorectal carcinoma: The expression levels of SMAD5 (Figure 2(e)) and SMAD6 (Figure 2(f)) in CRC tissues were significantly higher than those in adjacent normal colorectal tissues (p < 0.001), and the statistical results were 4.364 ± 0.723 vs. 3.952 ± 0.446 and 2.916 ± 0.64 vs. 2.085 ± 0.394, respectively.