The present invention provides a method for predicting the therapeutic effect of chemotherapy using an anti-tumor agent that contains trifluridine and tipiracil hydrochloride at a molar ratio of 1:0.5 on a colorectal cancer patient, said method comprising the steps (1)-(3) that are indicated below. As a means of solving the problem addressed by the present invention, a method comprising the following steps is provided: a step (1) in which the expression of the TK1 protein in the cytoplasm of a tumor cell that is included in a biological sample taken from the patient is detected using immunohistochemistry a step (2) in which tumor cells are classified as positive cells and negative cells from the detection result obtained at step (1) and the share of positive cells among the tumor cells is calculated and a step (3) in which, when the share is 30% or higher, it is predicted from the calculation result obtained at step (2) that there is a high possibility that chemotherapy using an anti-tumor agent that contains trifluridine and tipiracil hydrochloride at a molar ratio of 1:0.5 will have a sufficient therapeutic effect on the patient.本發明提供一種針對結腸直腸癌患者預測使用抗腫瘤劑之化學療法治療效果的方法,該抗腫瘤劑係以莫耳比1:0.5之比例含有三氟胸苷(trifluridine)與帝吡拉瑟鹽酸鹽(Tipiracil Hydrochloride),且該方法包含以下步驟(1)~(3)。作為解決此一課題之手段而提供下述發明。一種方法,包含:步驟(1),利用免疫組織化學法,檢測取自該患者之活體試料所含腫瘤細胞中之TK1蛋白質表現;步驟(2),依據上述步驟(1)所得檢測結果,將腫瘤細胞分類為陽性細胞與陰性細胞,並算出腫瘤細胞中之陽性細胞占有率;及,步驟(3),依據上述步驟(2)所得算出結果,在該占有率為30%以上時,即預測對該患者使用抗腫瘤劑之化學療法顯示出充分治療效果之可能性高,且該抗腫瘤劑係以莫耳比1:0.5之比例含有三氟胸苷與帝吡拉瑟鹽酸鹽。
