Abstract: In recent years,many scholars have made considerable progress in molecular research on colorectal cancer,and also gained a deep understanding of how to choose the best treatment plan through different states of molecular expression.In previous studies,RAS/RAF mutations have been considered biomarkers of poor prognosis.However,recent studies have shown that patients with RAS/RAF mutations have the opportunity to undergo interventions with inhibitors,turning them into better indicators of prognosis.The expanded RAS test is the latest predictor of whether a patient can respond to cetuximab and panitumumab combined chemotherapy.Combination therapy with dual inhibitors of EGFR/BRAF or BRAF/MEK in the MAP kinase signaling pathway can also clearly increase the survival of patients with BRAF mutations.More and more evidence shows that Her-2 can not only be applied to the treatment of breast cancer,but also can provide targeted therapy for trastuzumab in Her-2 expanded colorectal cancer patients.Immunotherapy is a novel treatment strategy for colorectal cancer,and many scholars are devoting themselves to develop markers of immune checkpoint inhibitors.Recently,MSI has been identified as a molecular marker for PD-1 treatment in patients with colorectal cancer.However,there are still some deviations from MSI's predictions,and it is believed that the more perfect marker TMB will be used to guide clinical immunotherapy soon.Our continuous understanding of biomarkers is constantly innovating and improving our treatment strategies for colorectal cancer.Although most patients with colorectal cancer still use conventional non-selective cytotoxic chemotherapeutic agents for treatment,more and more small subsets of patients with a certain genetic alteration will choose targeted therapies.It is believed that selective targeted drug therapy and immunotherapy will eventually replace traditional non-selective cytotoxic chemotherapy.In short,the simultaneous development of molecular markers and their latest therapeutic strategies provide great prospects for improving the prognosis of patients with colorectal cancer.

Key words: Colorectal cancer, RAS, RAF, MSI, TMB, Predictive biomarker