GAPDH and neoplasm: The housekeeping gene (GAPDH) was used to determine the degree of non-specific background RNA message present in the samples (inlet, outlet, and EVHB-Chip), with a similar comparison demonstrating markedly higher GAPDH RNA positive events in the ultracentrifuged samples (input: 1857; output: 1696; microfluidic chip: 236, n = 2), supporting that EVs isolated from the EVHB-Chip yield much higher levels of tumor-specific RNA (EGFRvIII), while having significantly less background RNA from not-tumor EVs (GAPDH).