The present invention provides a novel method for determining cancer malignancy, a novel cancer diagnostic method, a novel method for determining prognosis, a novel vaccine for cancer treatment, and a novel vaccine for suppressing cancer metastasis. Specifically, the invention provides a cancer malignancy evaluation method that comprises the step of measuring a DDX3X expression level in a cancer tissue, and the step of evaluating malignancy of the cancer tissue by using the DDX3X expression level.本發明提出一新穎癌症惡性度之決定方法、一新穎癌症診斷方法、一新穎預後決定方法、一新穎用於癌症治療之疫苗、及一新穎用於遏止癌症轉移之疫苗。更明確言之，本發明提出一種癌症惡性度之評估方法，該方法係包含量測於癌症組織中的DDX3X表現程度之步驟，及藉使用該DDX3X表現程度評估該癌症組織的惡性度之步驟。
