CTLA4 and colorectal carcinoma: Knockdown PD-L1 and CTLA-4 gene expression. Decreased apoptosis of CD8+ T cells and increased their percentage in co-cultures, upregulated the expression of TNF-α, IFN-γ and IL-2. Inhibit CRC cell proliferation, repress immune escape of CRC cells, activate an anti-tumor response, and suppress tumor growth in vivo