CXCR4 and Leigh syndrome: In contrast, CD8 effector cells exhibited downregulation of multiple key genes involved in tumor-suppressive transcriptional regulation (HIST1H1C, ZNF331, KLF6, and BTG1) and immune activation and trafficking (CXCR4, CD69, and TNFAIP3) in LS carriers, which was more severe in LS-CRC (Figure S6D; Table S6).