While BRCA1 promoter hypermethylation is frequent in TNBC [24] it is well established that somatic hypermethylation underlying, e.g., the RB1 gene hypermethylation in retinoblastoma [25] or the CIMP-phenotypes of colorectal cancer [1] or glioblastoma multiforme [2] only affects a subset of all tumors of a given cancer type. Here, RB1 is linked to cancer.