目的 研究血清microRNA-497（miR-497）在结直肠癌（CRC）患者的表达特征，分析其与临床病理参数、诊断价值及患者预后的相关性。 方法 对医院2020年3月至2022年3月期间收治的122例CRC患者（CRC组）进行资料整理，筛选出100例健康体检人群作为对照组。所有受试者在术前采集血清样本，利用实时定量PCR技术检测血清中miR-497的表达水平，并同步测定CEA与CA199水平。进一步分析miR-497表达与临床病理变量之间的关系，通过受试者工作特征（ROC）曲线评估其诊断能力，并采用Kaplan-Meier生存分析与Cox回归模型探讨其对患者预后的影响。 结果 CRC组血清miR-497表达水平显著低于健康对照组（P < 0.001）。miR-497表达与TNM分期及淋巴结转移密切相关（P < 0.001），而与肿瘤位置、性别、年龄等无显著相关性。ROC曲线分析显示miR-497在CRC诊断中的AUC为0.845，优于CEA（0.748）和CA199（0.702），DeLong检验表明miR-497与CEA、CA199的AUC差异均有统计学意义（P < 0.05）。Kaplan-Meier生存分析显示，miR-497高表达组患者的3年DFS率显著优于低表达组（84.06% vs. 64.58%）。高表达组中位DFS未达到，而低表达组中位DFS为36个月，组间差异有统计学意义（P = 0.015）。Cox回归分析显示，miR-497低表达（HR = 1.923，95%CI：1.184 ~ 3.125）、TNM分期（HR = 2.511，95%CI：1.421 ~ 4.437）及淋巴结转移（HR = 1.753，95%CI：1.151 ~ 2.664）是影响CRC患者DFS的独立危险因素。 结论 血清miR-497在CRC患者中呈低表达状态，且与肿瘤进展及不良预后密切相关，具有较高的诊断价值和预后评估潜力，可望作为CRC的辅助诊断和预后判断的潜在生物标志物。

Objective To characterize the expression patterns of serum microRNA-497 （miR-497） in patients with colorectal cancer （CRC） and to investigate its associations with clinicopathological characteristics， diagnostic performance， and long-term prognostic outcomes. Methods This study retrospectively analyzed data from 122 patients with CRC admitted to the hospital between March 2020 and March 2022 （CRC group）， and enrolled 100 healthy individuals undergoing routine physical examinations （healthy control group） for comparison. Serum samples were collected from all participants prior to any surgical intervention， and the expression levels of miR-497 in serum were quantified using real-time quantitative polymerase chain reaction （qRT-PCR）. Simultaneously， the levels of carcinoembryonic antigen （CEA） and carbohydrate antigen 199 （CA199） were measured. To investigate the association between miR-497 expression and clinicopathological characteristics， we evaluated its diagnostic performance using receiver operating characteristic （ROC） curve analysis. Furthermore， Kaplan-Meier survival analysis and Cox proportional hazards regression models were employed to assess its impact on patient prognosis. Results Compared to healthy individuals， CRC patients exhibited significantly lower serum miR-497 expression levels （P < 0.001）. Notably， miR-497 expression was strongly correlated with TNM stage progression and lymph node metastasis （P < 0.001）， but showed no significant association with tumor location， patient sex， or age. Diagnostic evaluation using ROC curves demonstrated that miR-497 achieved an AUC of 0.845 for CRC detection， outperforming CEA （AUC = 0.748） and CA19-9 （AUC = 0.702）， with DeLong′s test confirming the statistically significant differences （P < 0.05）. Kaplan-Meier survival analysis revealed a significantly higher 3-year DFS rate among patients with high miR-497 expression （84.06%） compared to those with low expression （64.58%）， with median DFS not reached in the high-expression group versus 36 months in the low-expression group （P = 0.015）. Multivariate Cox regression analysis confirmed that reduced miR-497 expression （HR = 1.923， 95% CI： 1.184 ~ 3.125）， advanced TNM stage （HR = 2.511， 95% CI： 1.421 ~ 4.437）， and lymph node metastasis （HR = 1.753， 95% CI： 1.151 ~ 2.664） were independently associated with poorer disease-free survival outcomes. Conclusions Serum miR-497 is downregulated in patients with CRC and is significantly associated with tumor progression and poor prognosis. It demonstrates high diagnostic accuracy and strong potential for prognostic evaluation， highlighting its promise as a biomarker for auxiliary diagnosis and outcome prediction in CRC.