After RASSF1A was overexpressed by lentivirus infection or treatment with 5‐Aza‐CdR, YAP expression was found to be down‐regulated, along with up‐regulation of pS127‐YAP, p‐LATS1/2 and p‐MST1/2 protein expression, indicating that RASSF1A controls YAP expression through phosphorylation of the Hippo signalling pathway. The gene discussed is RASSF1; the disease is lentivirus infection.