PROBLEM TO BE SOLVED: To provide means having improved effect of treating cancer through the activity of inhibiting the expression of a PSF1 gene.SOLUTION: A PSF1 gene expression inhibitor comprises extract of one or more plants selected from the group consisting of Trigonotis peduncularis, Elatostema involucratum, Tetramerista glabra, and Heliconia collinsiana.COPYRIGHT: (C)2015,JPO&INPIT【課題】PSF1遺伝子の発現抑制活性を通じた、より効果的ながんの治療手段を提供すること。【解決手段】キュウリグサ、ウワバミソウ、プナー、及びヘリコニア・コリンシアナから成る群より選択される1種以上の植物の抽出物を含む、PSF1遺伝子発現抑制剤。【選択図】図2