Screening Value And Clinical Significance Of Plasma Exosome MiR-221-3p For Colorectal Cancer

Colorectal cancer is one of the common clinical malignant tumors,and its incidence and mortality rate increase year by year.Most patients have atypical early symptoms and lack of highly sensitive serological markers to screen for colorectal cancer,and most patients are diagnosed at an advanced stage,with single treatment and poor prognosis.Exosomes are tiny vesicles with a diameter of about 40-160 nm,which are rich in a variety of proteins,miRNAs(micro RNAs),DNA and other substances,participate in tumor development and widely exist in the body fluid circulation,and its membrane structure can be used as a "protective film" to keep the bioactive factors in it relatively stable.Based on this feature,it is possible to apply exosome miRNAs as tumor markers in the clinic.Through the early gene sequencing results of the research group,it was found that the expression of miR-221-3p in colorectal cancer cells was increased,but no large-sample verification was carried out,and at the same time,it was found that plasma miR-221-3p expression was elevated in pancreatic cancer and gastric cancer by reviewing the literature,which conjectured that miR-221-3p became a potential diagnostic marker through exosome secretion into the blood circulation,and there are few reports on the screening and clinical significance of plasma exosome miR-221-3p in colorectal cancer.Objective:The expression of miR-221-3p and plasma exosome miR-221-3p in colorectal cancer tissues was clarified,and the screening value of plasma exosome miR-221-3p for colorectal cancer and its relationship with clinicopathological features were analyzed.Methods:From February 2022 to November 2022,50 cases of colorectal cancer and adjacent paired tissues were collected in the Department of Gastroenterology and Gastrointestinal Surgery of the Affiliated Hospital of Chengde Medical College from February 2022 to November 2022,and 23 cases of colorectal cancer and adjacent paired tissues were collected by surgical resection,and all of them were first diagnosed as colorectal cancer by colonoscopy and pathological results,and 47 healthy patients in the physical examination department were collected as healthy groups during the same period,fasting venous blood was collected.Circulating plasma exosomes were extracted by kit method,and exosomes were identified by transmission electron microscopy,particle size analysis and Western Blot method.The expression of miR-221-3p and plasma exosome miR-221-3p in colorectal cancer and adjacent tissues was detected by RT-q PCR,and the expression of plasma CEA was detected by chemiluminescence immunoassay.At the same time,the basic clinical information and pathological results of the enrolled population were collected,and statistical analysis was carried out based on the experimental results.Results:1.Expression of miR-221-3p in colorectal cancer and adjacent tissuesThe expression of miR-221-3p in colorectal cancer tissues was much higher than that in adjacent tissues(P<0.05),and the results were statistically different.2.Identification of plasma exosomesThe extracted plasma exosomes were identified by transmission electron microscopy scanning,particle size analysis and Western Blot detection,and the results of electron microscopy showed that the exosomes had a typical vesicle structure,and the particle size analysis showed that the average particle size was 124.6nm,the main peak of particle size was 107 nm,and the specific proteins CD9 and CD63 were expressed in Western Blot detection.3.Expression of plasma exosome miR-221-3p in colorectal cancer group and healthy groupThe expression level of plasma exosome miR-221-3p in the colorectal cancer group was higher than that in the healthy group(P<0.05),and the difference was statistically significant.4.Diagnostic value of plasma exosome miR-221-3p,plasma CEA and their combination for colorectal cancerThe area under the ROC curve of plasma exosome miR-221-3p for the diagnosis of colorectal cancer was 0.740,with a sensitivity of 0.760 and specificity of 0.640;the area under the ROC curve for the diagnosis of colorectal cancer was 0.787,the sensitivity was 0.680 and the specificity was0.830;The area under the ROC curve for the diagnosis of colorectal cancer was 0.818,the sensitivity was 0.890,and the specificity was 0.680.5.Differential expression of plasma exosome miR-221-3p among groups with different clinicopathological featuresThe results showed that the expression of plasma exosome miR-221-3p in TNM stages III.-IV.was higher than that in stages I.-II.(P<0.05).TNM stage depends on three factors: depth of invasion,lymph node metastasis,and distant metastasis.Further analysis showed that the expression of exosome miR-221-3p in stage III.-IV.patients with lymph node metastasis was higher than that in stage I.-II.patients without lymph node metastasis(P<0.05),similarly,it was expressed in stage IV.patients with distant metastases than in the first 3 stage patients without distant metastasis(P<0.05),but there was no expression difference between different groups classified by invasion depth,tumor site and tumor size(P>0.05).6.Correlation analysis of plasma exosome miR-221-3p expression with clinicopathological featuresSpearman correlation analysis showed that plasma exosome miR-221-3p was positively correlated with lymph node metastasis and distant metastasis(P<0.05)in colorectal cancer group,but not with tumor site,tumor size and depth of invasion(P>0.05).Conclusions:1.The combined detection of plasma exosome miR-221-3p and CEA improves the sensitivity and has certain value for colorectal cancer screening;2.High expression of plasma exosome miR-221-3p may indicate metastasis and has certain value for evaluating tumor stage.