PITX1 and neoplasm: Our data revealed that ccf-mtDNA fragments with tumor-specific mutations were significantly shorter than wild-type ccf-mtDNA fragments (P < 0.001; Fig. 5F), and had a lower 5′ C-end base preference, higher 5′ A-end base preference, and larger MDS (P < 0.001; Appendix Fig. S13a,b).