结直肠癌是全球第三高发的肿瘤，转移性结直肠癌则是临床治疗中的难题，全身性化疗以及靶向治疗是这些患者首选的治疗方法，但肿瘤的异质性决定了不同患者对化疗的敏感性存在差异，目前仍缺乏有效的方法来预测药物的疗效，现有用生物学标记来筛选患者的方法存在缺陷。利用患者手术标本建立的移植瘤模型（Patient-Derived Xenograft，PDX）可以保留患者肿瘤组织学及生物学特征，对药物敏感性和耐药性预测的准确率高达90%及97%，该模型在转移性结直肠癌的个体化治疗中的研究尚未见报道。在本项目中我们将建立转移性结直肠癌患者PDX模型，比较患者肿瘤与PDX的组织学及生物学特征，观察患者及PDX模型对化疗药物的敏感性，筛选敏感的药物并指导患者的治疗。为转移性结直肠癌的治疗提供新的个体化治疗策略。

Colorectal cancer is the third most common malignant tumor worldwide. Metastasis colorectal cancer patients have very poor prognosis, systemic chemotherapy and targeted therapy is the preferred method of treatment of these patients. However, the heterogeneity of the tumor determines different sensitivity to chemotherapy. Notwithstanding the importance of biomarker-driven approaches for cancer treatment, it has several challenges. It has been demonstrated that xenografts created via the direct engraftment of patient biopsies (PDX) into animals maintain the histological and biological characteristic of the original patient tumors. The drug response of PDX was highly correlated with the clinical outcome of the patients, and correctly predicted the response in 90% of patients and resistance in 97% of patients. In this program we will establish PDX with colorectal cancer. We next treat these PDX with different chemotherapeutics and evaluate the response. After collecting the clinical data of patient we will evaluate the predictability of these xenografts on the response of chemotherapeutics. Result will be used to guide the individual cancer therapy. This work will provide new therapeutic strategies for the treatment of metastatic colorectal cancer.