SERPINE1 and neoplasm: Despite showing only a partial overlap of the differentially secreted proteins (Fig 2D), both primitive tumor‐derived cell lines specifically secrete proteins belonging to ECM matrix degradation (MMP1), Wnt signaling pathway (WNT5a), TGFB signaling pathway (TPM4), proteoglycan degradation (SPOCK1), and platelet activation (VEGFC, SERPINE1, EDIL3).