PRMT9 and hepatocellular carcinoma: In hepatocellular carcinoma, PRMT9 promotes invasion and metastasis through activation of the PI3K/Akt/GSK-3β/Snail signaling pathway, and patients with high PRMT9 expression were found to have a short survival time and a high recurrence rate [153], indicating that PRMT9 is associated with poor tumor prognosis.