Two hundred forty-three serum samples from 89 patients with IDC, 30 patients with DCIS, and 125 age-matched healthy controls were examined. After DNA extraction and sodium bisulfite treatment, QM-MSP was performed for HIN-1, RASSF1A, RAR-β, and Twist.
Overall significant differences in methylation levels were observed for HIN-1 (p = 0.006), RAR-β (p < 0.001), RASSF1A (p = 0.004), and Twist (p < 0.001). All four genes showed significantly higher methylation frequencies in DCIS or IDC than in control subjects (p < 0.001 for all comparisons). However, methylation frequencies were not significantly different between DCIS and IDC. In receiver-operating characteristic analysis, the two-gene combination (RAR-β/RASSF1A) showed the best performance in distinguishing DCIS/IDC from control samples. The estimated specificity of this two-gene panel for detecting DCIS/IDC was 88.8 % , and its sensitivity was 94.1 % .
The quantitative detection of aberrant DNA methylation in serum samples may be a promising high throughput approach for the diagnosis of breast cancer including DCIS.