PECAM1 and neoplasm: A study found that CD31 was increased at 7 days after IRE (1000 V; 100 ms; 1 Hz; 80 pulses) in the tumor area (46), but some studies found that CD31 was increased on day 4 after IRE (200 V/960 V, 100 us, 1 Hz, 20 pulses) but fell back at day 7 (36).