As illustrated in Figure 2A, we identified 18 altered genes with the frequency of more than 10% in pericardial effusion-cfDNA and pericardial effusion-sDNA, which included EGFR (54%), TP53 (50%), MLH1 (35%), KRAS (23%), MTOR (15%), MSH6 (15%), MSH2 (15%), IDH1 (15%), DICER1 (15%), CTNNB1 (15%), ATM (15%), FLT3 (12%), ARID1A (12%), EP300 (12%), CDKN2A (12%), PIK3C2G (12%), PTEN (12%), and AMER1 (12%). The gene discussed is PIK3C2G; the disease is pericardial effusion.