PDCD1 and cancer: Interestingly, the most important enriched KEGG pathways of BPIFB2 included cell cycle, Human T-cell leukemia virus 1 infection, Th17 cell differentiation, human immunodeficiency virus 1 infection, Th1 and Th2 cell differentiation, PD-L1 expression and PD-1 checkpoint pathway in cancer (Fig. 10) (p.adjust < 0.05).