Abstract:
Objective To investigate the diagnostic value of plasma short stature homeobox 2 (SHOX2), Ras association domain family 1A (RASSF1A) and prostaglandin E receptor 4 (PTGER4) gene methylation detection combined with low-dose CT (LDCT) for malignant pulmonary nodules.
Methods A total of 153 hospitalized patients with pulmonary nodules scheduled for surgical treatment were selected as study subjects. The Ct values of the target genes SHOX2, RASSF1A, PTGER4 and the internal reference gene ACTB in the patients' plasma were detected, and the ΔCt values (ΔCttarget gene -Ctinternal reference gene) and the three-gene fitting positive index (PI) of each gene were further calculated. The sensitivity and specificity of ΔCt values and the three-gene fitting PI as methylation-positive diagnostic criteria for malignant pulmonary nodules were analyzed. Receiver operating characteristic (ROC) curves were plotted to evaluate the diagnostic value of LDCT combined with gene methylation detection for malignant pulmonary nodules.
Results According to the pathological results, the patients were divided into benign pulmonary nodule group (47 cases) and malignant nodule group (106 cases). The sensitivity and specificity of the three-gene fitting PI for diagnosing malignant pulmonary nodules were 58.49% and 70.21%, respectively. The sensitivities of ΔCtSHOX2, ΔCtRASSF1A and ΔCtPTGER4 values for diagnosing malignant pulmonary nodules alone and their combination were 33.96%, 43.40%, 49.06% and 75.47%, respectively, and the specificities were 87.23%, 72.34%, 80.85% and 100.00%, respectively. Compared with the three-gene fitting PI, ΔCt values were more suitable for the differential diagnosis of benign and malignant pulmonary nodules. Based on the pathological diagnosis results, there was a statistically significant difference in the positive rates of malignant pulmonary nodules between LDCT diagnosis and gene methylation combined with LDCT diagnosis (P < 0.001). ROC curve analysis showed that the areas under the curves (AUCs) for diagnosing malignant pulmonary nodules using plasma SHOX2, RASSF1A, PTGER4 gene methylation ΔCt values, LDCT alone, and their combination were 0.604, 0.582, 0.629, 0.668 and 0.981, respectively. The diagnostic value of the combined indicators was higher than that of single indicators.
Conclusion LDCT combined with plasma SHOX2, RASSF1A, PTGER4 gene methylation detection has high diagnostic efficacy for malignant pulmonary nodules and can significantly reduce the false-positive rate of LDCT in early screening of lung cancer.