PROS1 and neoplasm: In the renin-angiotensin system, angiotensin-converting enzyme 2 (ACE2), a receptor that can be bound by the SARS-CoV-2 surface spike (S) protein and mediate viral entry [8], is known to be widely expressed in tumor cells [9–12], suggesting that ACE2 is likely to be present on the membrane surface of tumor cell MPs.