KRAS and colorectal cancer: K-Ras expression slightly increases in DLD-1(human colorectal cancer cell line grown in medium containing non-essential amino acids), while CTNNA1, β-catenin, and E-cadherin show a significant decrease compared with those in control Coca-2 (human colorectal cancer cell line grown in medium without non-essential amino acids) 20, suggesting that K-Ras may interact with the E-cadherin-catenin complex 20.