For the cytotoxicity test, PBMCs from CRC patients and normal individuals in the PBMC, PBMC+IL2, PBMC+PC, and PBMC+G2 groups were co-cultured with K562 cells in effector-to-target cells ratios of 5:1 and 10:1 (Figure 3). Here, IL2 is linked to colorectal carcinoma.