目的:探析局部进展期低位直肠癌采用XELOX新辅助化疗后癌组织恶性生物学标志基因表达水平，为临床治疗提供指导。方法:基于既定纳入及排除标准选取2017年1月至2018年1月青岛大学附属医院接治的104例局部进展期低位直肠癌患者纳入观察研究中，基于乱数表法分成观察组和对照组，各52例；两组均行肿瘤根治术，对照组直接实施根治术，观察组行XELOX新辅助化疗＋根治术，对比分析两组癌灶切除效果，并测定术后血清肿瘤标志物和癌灶内恶性生物学标志基因表达水平，随访掌握两组术后3年生存率。结果:观察组癌灶R0切除率为96.15%，对照组为80.77%，相比差异有统计学意义(n P0.05)；术后1周时，观察组血清CA19-9、CEA、CA50水平均显著低于对照组(n P<0.05)。术后观察组癌灶组织内PPTG、Smad4的mRNA表达量低于对照组，而Runx3、APC的mRNA表达量高于对照组，差异均有统计学意义(n P<0.05)。观察组随访3年生存率为90.38%，显著高于对照组的78.85%(n P<0.05)。n 结论:在局部进展期低位直肠癌根治术中应用XELOX新辅助化疗，可降低肿瘤恶性程度，提高癌灶切除效果，改善生存期，有着重要临床价值。“,”Objective:To analyze the expression level of malignant biological marker gene in locally advanced low rectal cancer tissues after neoadjuvant chemotherapy with XELOX, so as to provide guidance for clinical treatment.Methods:Based on the established inclusion and exclusion criteria, 104 patients with locally advanced low rectal cancer treated in the Surgery Department of the Affiliate Hospital of Qingdao University from January 2017 to January 2018 were included in the study. Based on the random number table method, they were divided into observation group and control group, with 52 patients in each group. Radical resection was performed in both groups, while radical resection was performed directly in the control group, and neoadjuvant chemotherapy with XELOX plus radical resection was performed in the observation group. The effect of tumor resection in the two groups was compared and analyzed, and the expression levels of tumor markers and malignant biological marker genes in the tumor tissues after surgery were determined. The 3-year postoperative survival rate of the two groups was followed up.Results:The R0 resection rate was 96.15% in the observation group and 80.77% in the control group, with statistically significant difference (n P0.05). One week after the operation, the serum levels of CA19-9, CEA and CA50 in the observation group were significantly lower than those in the control group (n P<0.05). Through detection, the relative mRNA expression levels of PPTG and Smad4 in the postoperative observation group were higher than those in the control group, while the relative mRNA expression levels of Runx3 and APC were lower than those in the control group, with statistically significant difference (n P<0.05). The 3-year follow-up survival rate in the observation group was 90.38%, significantly higher than 78.85% in the control group (n P<0.05).n Conclusions:The application of XELOX neoadjuvant chemotherapy in radical resection of locally advanced low rectal cancer has important clinical value in reducing tumor malignancy, improving tumor resection effect and improving survival.