探寻与结肠癌发生高关联的原癌基因，并研究其临床应用前景，能够为精准医疗提供更多选择。Fyn是Src家族的一种非受体酪氨酸激酶，参与多种人体生理功能和肿瘤进程，然而其在人结肠癌中的作用仍不清楚。我们的预实验显示Fyn在部分结肠癌细胞中高表达，在结肠正常细胞中低表达。基因沉默Fyn减弱5-Fu诱导的结肠癌细胞凋亡，提示Fyn在结肠癌中高表达促进结肠癌细胞凋亡。我们还发现Fyn能够直接磷酸化caspase-9并与之相结合。文献显示酪氨酸激酶对caspase-9的磷酸化使其活性增高，因此我们假设同样是酪氨酸激酶的Fyn可能通过磷酸化促进caspase-9的活性。本课题将围绕现有基础进一步开展工作，确定Fyn对结肠癌细胞凋亡的影响，深入探索Fyn磷酸化caspase-9调控结肠癌凋亡的机制，收集术前经5-Fu化疗的IV期结肠癌患者标本验证Fyn与凋亡的相关性，为提高结肠癌化疗效果提供切实的理论依据。

Exploring the proto oncogene that tightly related to colon cancer and evaluating the prospect of their clinical applications, can provide more options for precision medicine. Fyn is a non receptor tyrosine kinase of the Src family. It is involved in many kinds of human physiological functions and tumor progression. However, its role in human colon cancer is still not clear. Our preliminary data showed that Fyn was highly expressed in several colon cancer cells, while the expression was low in normal cells. Knockdown of Fyn attenuated 5-Fu induced apoptosis of colon cancer cells, which suggested that highly expressed Fyn may promote the apoptosis of colon cancer cells. We also found that Fyn directly phosphorylated caspase-9 and combined with caspase-9. The literature shows that tyrosine kinase phosphorylation of caspase-9 increased its activity. So we assume that Fyn may also promote the activity of caspase-9 by phosphorylation. This study will continue working based on existing data, determine the effect of Fyn on apoptosis in human colon cancer cells, and further explore the mechanism of regulating colon cancer apoptosis by Fyn phosphorylating caspase-9. Collect patient sample who suffered stage IV colon cancer and received preoperative 5-Fu chemotherapy, and then use the sample verify the relevance between Fyn and apoptosis, Our aim is to provide theoretical basis for improving the effect of colon cancer chemotherapy.