CD8A and colorectal carcinoma: Notably, chondroitin sulfate synthase 1 (CHSY1) was upregulated in both primary CRC and hepatic metastases, where it reprogramed succinate metabolism and activated the PI3K/AKT/HIF1A axis, driving CD8+ T-cell exhaustion and elevating PD-L1 expression to facilitate liver colonization (Sun et al., 2023).