CASP9 and colorectal cancer: The combined effect group of RES and VE could significantly upregulate the expression of pro-apoptotic proteins BAX, Caspase-3, Caspase-8, and Caspase-9 and downregulate the expression of anti-apoptotic protein BCL-2 compared with the single component group, thus demonstrating that RES and VE synergistically promote apoptosis in colorectal cancer cells effectively.