KEGG pathway analysis was carried out to indicate that PrPC is related to the pathway of prion disease (P<0.01), and DEPs are statistically enriched in focal adhesion, small cell lung cancer, toxoplasmosis, PI3K-Akt signaling pathway, ECM-receptor interaction, amoebiasis and human papillomavirus infection (P<0.0001) (Fig. 5C). Here, PRNP is linked to human papilloma virus infection.