Fig. 6

Methylated 5-gene marker panel accurately detects stage IV CRC in plasma. To identify a minimal marker subset of the 8-gene panel, cMethDNA results were re-analyzed using a subset of 5 of 8 plasma markers after selecting for individual plasma markers with the least background in normal and the highest methylation in CRC plasma (Additional file 1: Figs. S2, S3). A Histogram plot. For each sample (X-axis), the height of the histogram bar indicates the level of cumulative methylation (Y-axis), each colored segment represents an individual gene, and the size of the segment is proportional to the %M of that gene. B Box–whiskers plot. Comparing CRC versus normal control plasma, significantly higher cumulative methylation of the 5-gene panel was observed in stage IV CRC (X-axis; Mann–Whitney, P < 0.0001). C Receiver operating characteristic (ROC). The 5-gene panel, with negligible methylation in normal plasma identified samples from patients with stage IV CRC versus normal controls with a sensitivity of 100% and specificity of 100% (AUC 1.0, P < 0.0001) at a threshold of 3.5 CMI. Additional file 1: Fig. S5 shows the performance of the same panel in tissue using QM-MSP