PROBLEM TO BE SOLVED: To provide a double-stranded nucleic acid molecule that can effectively suppress the growth of cancer cells and is used for cancer prevention and/or treatment, as well as a cancer cell growth inhibitor comprising at least one of the double-stranded nucleic acid molecule, DNA comprising a sequence encoding the double-stranded nucleic acid molecule, a vector containing the DNA； a medicine comprising the cancer cell growth inhibitor； a method for determining the proliferative ability of ovarian cancer cells； a method for determining the resistance of an ovarian cancer individual to an ovarian cancer therapeutic agent, and a method for determining the efficacy of the medicine in an ovarian cancer individual.SOLUTION: Provided is a double-stranded nucleic acid molecule for suppressing the expression of SPON1 gene, which comprises an antisense strand comprising (a) a sense strand comprising a specific nucleotide sequence, and (b) an antisense strand comprising a nucleotide sequence complementary to the sense strand forming a double strand with the sense strand of (a), and SPON1-TRIM29 fusion gene which is a fusion gene with the TRIM29 gene.SELECTED DRAWING: NoneCOPYRIGHT: (C)2020,JPO&INPIT【課題】がん細胞の増殖を効果的に抑制することができ、がんの予防及び／又は治療に用いる二本鎖核酸分子の提供。前記二本鎖核酸分子、前記二本鎖核酸分子をコードする配列を含むＤＮＡ、前記ＤＮＡを含むベクター、の少なくともいずれかを含むがん細胞増殖抑制剤、前記がん細胞増殖抑制剤を含む医薬、卵巣がん細胞の増殖能を判定する方法、卵巣がん個体の卵巣がん治療薬に対する抵抗性を判定する方法、及び、卵巣がん個体における前記医薬の有効性を判定する方法、の提供。【解決手段】（ａ）特定のヌクレオチド配列を含むセンス鎖、（ｂ）前記（ａ）のセンス鎖と二本鎖を形成する該センス鎖に相補的なヌクレオチド配列を含むアンチセンス鎖、とを含むＳＰＯＮ１遺伝子、及び、ＴＲＩＭ２９遺伝子との融合遺伝子であるＳＰＯＮ１－ＴＲＩＭ２９融合遺伝子の発現を抑制するための二本鎖核酸分子。【選択図】なし
