Large genome‐wide association studies (GWAS) have reported associations between high‐frequency genomic variants localizing to the TET2 gene and the risk of several human cancers, including melanoma [14], breast cancer [15, 16], colorectal cancer [17, 18, 19], endometrial cancer [18] and prostate cancer (PCa) [20, 21, 22, 23, 24]. Here, TET2 is linked to breast cancer.