CD9 is broadly expressed in non-small cell lungcancer (NSCLC) lines but is absent or highly reduced in most smallcell lung cancer (SCLC) lines, while CD63 and CD81 are broadly expressedin both SCLC and NSCLC lines.28 Antibodymolecules, specific to selected tetraspanins, were introduced to thereceptor layer in an orientation consistent with vertical orientationthrough protein A (SPR detection) or a cysteamine layer (QCM-D detection).The simultaneous determination of these three tetraspanins presentin the membrane of EVs can be applied to lung cancer diagnosis. Here, CD9 is linked to small cell lung carcinoma.