ERBB2 and neoplasm: In summary, in the presented immuno-PCR method, different tumor-membrane receptors can be quantified on sEVs from liquid biopsies, e.g., MPE-fluid samples, which may offer a way to analyze possible bypassing signaling via detection of changes in the expression level of membrane receptors EGFR, HER2, and IGF-1R under TKI treatment.