AKT1 and cancer: Figure 1E illustrates the top 20 ranked significant pathways for DE piRNA targets in KEGG. The targets of upregulated piRNAs were primarily enriched in the PI3K–Akt signaling pathway, Rap1 signaling pathway, cAMP signaling pathway, axon guidance, regulation of the actin cytoskeleton, calcium signaling pathway, proteoglycans in cancer, and so on (Figure S2C). Downregulated piRNA targets were also enriched in many important pathways, such as the PI3K– Akt signaling pathway, MAPK signaling pathway, Th17 cell differentiation, cGMP–PKG signaling pathway, and ECM–receptor interaction (Figure S2D).