ZFHX3 methylation in peripheral blood monocytes as a potential biomarker for pancreatic cancer detection

Pancreatic ductal adenocarcinoma (PDAC) is the digestive malignancy with poor prognosis, and there is still a lack of effective diagnostic biomarkers. We aimed to explore the diagnostic efficiency of DNA methylation in peripheral blood monocytes (PBMCs) in PDAC. 850K BeadChips were used to detect genome-wide methylation of PBMCs. For the selected sites, MethylTarget assays was used for further verification. The support vector machine was used to establish the combined panel. A total of 167 PDAC patients and 113 healthy controls were included in this study and were divided into three sets. In the discovery set, we found 4625 differentially methylated positions (DMPs) between cancer group and healthy controls. ZFHX3 (0.16±0.04 vs. 0.18±0.04, P=0.001), cg01904886 (0.84±0.05 vs. 0.81±0.04, P=0.02) and NUMBL (0.96±0.005 vs. 0.957±0.005, P=0.04) were found to be significantly different in training set. The locus with more significant differences, namely ZFHX3, was used for further validation and to establish a combined diagnostic panel with CA19-9. In the validation set, the ROC curve indicated that the AUC value of ZFHX3 was 0.75. The AUC value of the combined model (AUC=0.92) was higher than that of CA19-9 alone (AUC=0.88). In patients with normal CA19-9 levels, the ZFHX3 methylation biomarker still maintained good diagnostic efficacy (AUC=0.71). Our study preliminarily suggests that ZFHX3 methylation combined with CA19-9 can improve the detection rate of PDAC. Especially in patients with normal CA19-9, ZFHX3 methylation can maintain stable diagnostic efficacy. The diagnostic value of ZFHX3 methylation still needs to be prospectively validated.