CD63 and pericardial effusion: The expression of α3 and β1 integrin subunits was found in exosomes isolated from the supernatant of 4 lung adenocarcinoma cell lines A549, H1975, H3255, and H1650 and a patient pericardial effusion by Western blots using exosomal (CD63) and cellular-specific (β-actin) markers (Fig. 1f).