For the remaining cancers, we find that the degree of COL17A1 promoter methylation is significantly reduced in the tumor samples (n = 516, n = 435, n = 361, respectively) compared to normal control samples (n = 50, n = 29, n = 41, respectively; p ≤ 0.0002, Mann-Whitney U test; Fig. 5a–c). Here, COL17A1 is linked to cancer.