Isolated CDCA1-derived epitope peptides having Th1 cell inducibility are disclosed herein. Such peptides can be recognized by MHC class II molecules and induce Th1 cells. In preferred embodiments, such a peptide of the present invention can promiscuously bind to MHC class II molecules and induce CDCA1-specific cytotoxic T lymphocytes (CTLs) in addition to Th1 cells. Such peptides are thus suitable for use in enhancing immune response in a subject, and accordingly find use in cancer immunotherapy, in particular, as cancer vaccines. Also disclosed herein are polynucleotides that encode any of the aforementioned peptides, APCs and Th1 cells induced by such peptides and methods of induction associated therewith. Pharmaceutical compositions that comprise any of the aforementioned components as active ingredients find use in the treatment and/or prevention of cancers or tumors including, for example, breast cancer, bladder cancer, esophageal cancer, small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC) and head-and-neck cancer (HNC).於此揭示具有Th1細胞誘導能力之單離的的自CDCA1衍生的抗原決定位胜肽。此種胜肽可藉由MHC第II類分子辨識並誘導Th1細胞。於較佳具體例中，此種本發明之胜肽可混雜地(promiscuously)結合於MHC第II類分子並且除了誘導Th1細胞更誘導CDCA1專一性細胞毒性T淋巴球(CTL)。因此此種胜肽適用於增強一對象中之免疫反應，因而於癌免疫療法中，特別是作為癌疫苗提供效用。於此也揭示編碼為任意上述胜肽的聚核苷酸、由此種胜肽所誘導的APC與Th1細胞，及與其相關的誘導方法。包含任意上述成分作為有效成分的醫藥組合物，提供效用於癌症或腫瘤之治療及/或預防，此癌症或腫瘤包括例如乳癌、膀胱癌、食道癌、小細胞肺癌(small cell lung cancer,SCLC)、非小細胞肺癌(non-small cell lung cancer,NSCLC)及頭頸癌(HNC)。
