Isolated EVs from the supernatant of the pleural effusion of an EGFR-TKI naïve patient (case 5) showed a mean size of 267.6 nm and concentration of 4.18 × 108 particles/mL, but isolated EVs from the supernatant of parapneumonic effusion of a patient with bacterial pneumonia displayed a mean size of 174.3 nm and concentration of 1.10 × 109 particles/mL. Here, EGFR is linked to bacterial pneumonia.