PDE5A and hepatitis B virus infection: For example, hepatitis B-related genes (GP1BA, HSPG2, CCL5, and SPP1), fatty liver diseases-related genes (COL3A1, CCL5, and SPP1), alcoholic liver diseases-related genes (CAV1, ELANE, CCL5, and SPP1), primary biliary cirrhosis-related genes (TGFB1, PDE5A, COL1A1, CCL5, and SPP1), and primary malignant liver neoplasm-related genes (SELP, PECAM1, HSPG2, and THY1), mainly expressed in endothelial and megakaryocyte, hardly expressed in any other cell types.