The present invention comprises: a double-stranded nucleic acid molecule for suppressing the expression of at least one of the TACC2 gene and the 14-3-3&zeta； gene, said double-stranded nucleic acid molecule including (a) a sense strand which has a nucleotide sequence corresponding to any of the target sequences of SEQ ID NO:1 to SEQ ID NO:18, and (b) an anti-sense strand which has a nucleotide sequence that is complementary to the sense strand of (a)； DNA and a vector which include the double-stranded nucleic acid molecule； a cancer cell proliferation inhibitor which includes at least one of the double-stranded nucleic acid molecule, the DNA, and the vector； and a pharmaceutical product which includes the cancer cell proliferation inhibitor.
