SERPINI1 and central nervous system cancer: However, in another in vitro study on glioma cells, Cen and colleagues showed that compared to sevoflurane, propofol significantly downregulated the potential tumor suppressors SERPINI1 and CAMK2A and upregulated the important immune checkpoint molecule CD274 (PDL 1), potentially resulting in the suppression of immune cell function and immune escape of glioma cells [16].