Archives

  • 2022-09
  • 2022-08
  • 2022-07
  • 2022-05
  • 2022-04
  • 2021-03
  • 2020-08
  • 2020-07
  • 2018-07
  • Suramin br relative quantitative method by Schmittgen and Livak F

    2022-09-13


    relative quantitative method by Schmittgen and Livak (2008): F = 2 4CT; 4CT = CTmiRNA-21-CTmiRNA-16, in which CT refers to the number of cycles corresponding to the setting threshold of the flu-orescent signal in each reaction tube.
    The Suramin of miRNA-31 and miRNA-let7 was detected by the same method as above.
    2.4. Statistical method
    SPSS19.0 was used to carry out statistical analysis of the above data. The normality test of measurement data was performed fol-lowed by independent-sample T-test for normally-distributed data and Mann-Whitney test for non-normally distributed. With a = 0.05 as the test level, the results are expressed as [median (Interquartile range)]. Receiver operating characteristic (ROC) curve was used to analyze the efficacy of plasma miRNA in the diagnosis of lung cancer, and Kaplan-Meier method was adopted to carry out the survival analysis of lung cancer patients.
    3. Results
    3.1. Comparison of expression of miRNA-21, miRNA-31 and miRNA-let7 in lung cancer group and healthy control group
    3.2. Relationship between clinical characteristics and plasma miRNA expression of lung cancer patients
    Fifty cases of lung cancer were classified according to the clini-copathological factors (age, gender, smoking history, mass size, lymph node metastasis) so as to analyze the relationship between the relative expression level of miRNA-21, miRNA-31, miRNA-let7 and the clinicopathological factors. Results indicated that lung can-cer patients with lymph node metastasis had higher expression level than those without lymph node metastasis (P < 0.05), but other clinicopathological factors were not correlated to the relative expression level of miRNA-21, miRNA-31, miRNA-let7 (P > 0.05). Details are shown in Table 2.
    3.3. Diagnostic efficacy of combined detection of miRNAs for lung cancer
    As indicated in ROC curve, the area under the curve (AUC) of plasma miRNA-21 was 0.653, and the sensitivity and specificity were 60% and 66.7%, respectively, with a statistical difference (P = 0.035). The AUC, sensitivity and specificity of miRNA-31 were
    Comparison of expression (2 4CT) of miRNA-21, miRNA-31 and miRNA-let7 in lung cancer group and healthy control group [median (quartile)].
    Note: * indicates a statistical difference; ** indicates a statistically significant different.
    Table 2
    Correlation between the expression (2 4CT) of plasma miRNA and clinical characteristics of lung cancer patients [median (quartile)] * 10 2.
    Patients N miRNA-21 miRNA-31 miRNA-Let7
    Age
    0.733, 60%, 75%, respectively, with a statistical difference (P = 0.001), and those of miRNA-let7 were 669, 54% and 58.3%, respectively, with a statistical difference (P = 0.019). The combined detection of miRNA-21 and miRNA-31 showed the AUC, sensitivity and specificity of 0.781, 70% and 70.8%, respectively. For the com-bined detection of miRNA-31 and miRNA-let7, the AUC, sensitivity and specificity were 0.732, 60% and 75%, respectively, but the com-bined detection of miRNA-21 and miRNA-let7 showed no statisti-cal difference. The combined detection of the three markers showed the AUC, sensitivity and specificity of 0.798, 72% and 75%, respectively, indicating the diagnostic efficiency of these three markers, and that their combination is more efficient for diagnosis. Details are sown in Fig. 1.
    3.4. Survival curve analysis
    According to the maximum Youden index of ROC curve, we obtained the optimal diagnostic critical values 2 4CT of miRNA-21, miRNA-31 and miRNA-let7, which were 0.065, 0.0025 and 0.0015. Based on that, patients were divided into high expression groups and low expression groups. Results showed that the median survival time in miRNA-21 high expression group was 24 months,
    and that in miRNA-21 low expression group was 35 months, and the difference was statistically significant (P < 0.05). The median survival time in miRNA-31 high expression group was 22 months, and that in miRNA-31 low expression group was 30 months, and the difference was statistically significant (P < 0.05). The median survival time in miRNA-let7 high expression group was 33 months, and that in miRNA-let7 low expression group was 24 months, and the difference was statistically significant (P < 0.05). Details are shown in Fig. 2.