MET and pericardial effusion: Next-generation sequencing on the pericardial effusion using a 520-genes panel (Burning Rock Biotech, Guangzhou, China) revealed EGFR L858R mutation (mutation allele frequency in pericardial effusion: 30.2%) accompanied by MET amplification (copy number in pericardial effusion: 4.8), CDK12 amplification (copy number in pericardial effusion: 11), ERBB2 amplification (copy number in pericardial effusion: 11).