SMAD4 and neoplasm: The matched primary tissue and blood samples had a shared mutated and unmutated consistency rate of 68.0% in TP53, 70.0% in APC, 88.0% in KRAS, 96.0% in SMAD4, 92.0% in PIK3CA, 84.0% in KMT2C, 94.0% in FBXW7, 90.0% in KMT2D, 94.0% in NF1, 96.0% in BRAF and 100% in NRAS, as shown in Figure 1B. Statistical analysis showed that all the 451 genes had no significant difference between the ctDNA and the tumor tissue by McNemar's test (P > 0.05).