PCDHA9 and breast cancer: As an example of TET2 CD–mediated gene activation, a subset of TSS-CGIs from the breast cancer-methylated PDCHA locus (6) selectively gained H3K4me3 in TET2 CD cells in correlation with the activation of the associated genes as shown for PCDHA4 (Fig 2K and L), PCDHA3, PCDHA9, and PCDHA10 (Figs 2K and S2G).