The present invention relates to a novel pharmaceutical composition for the treatment and / or prevention of cancer comprising a polynucleotide derived from various miRNAs associated with cancer as an active ingredient, and a pharmaceutical composition combining this pharmaceutical composition with another antitumor agent. The present invention also provides a method for treating or preventing a subject having cancer using these pharmaceutical compositions or combination pharmaceuticals. The present invention relates to a pharmaceutical composition for treating and / or preventing cancer comprising a polynucleotide comprising the nucleotide sequence represented by SEQ ID NO: 1 or 2 as an active ingredient (provided that at least a part of the polynucleotide is DNA). Uracil in the region corresponding to DNA in the base sequence is read as thymine).本発明は、癌と関連する様々なｍｉＲＮＡを由来とするポリヌクレオチドを有効成分とする新たな癌の治療及び／又は予防用医薬組成物、この医薬組成物と別の抗腫瘍剤との組み合わせ医薬品、並びに、これらの医薬組成物又は組み合わせ医薬品を用いて癌をもつ被検体を治療又は予防する方法を提供する。本発明は、配列番号１又は２で表される塩基配列を含むポリヌクレオチドを有効成分として含む、癌の治療及び／又は予防用医薬組成物（但し前記ポリヌクレオチドの少なくとも一部がＤＮＡである場合、前記塩基配列中のＤＮＡに相当する領域のウラシルはチミンに読み替える）に関する。
