MKI67 and neoplasm: As described in an earlier TRACERx cohort, histological evidence of necrosis (q = 2.2 × 10-13), tumour size (q = 2.8 × 10-5), Ki-67 fraction (q = 9.9 × 10-7), mitotic index (q = 1.1 × 10-4), degree of nuclear pleomorphism (nuclear grade, q = 2.3 × 10-4), and the presence of pleural invasion (q = 0.0014) were associated with pre-operative ctDNA detection9, but not with STAS positivity (Extended Data Fig. 7d).