To determine whether tumor secreted Pvf1 non-autonomously activates Hnf4 level in oenocytes, we knocked down Pvf1 expression in the ISCs of Yki flies (Esg>yki3SA; Pvf1-i) and observed its effect on Hnf4-127D01 nuclear level. The gene discussed is HNF4A; the disease is neoplasm.