In the genome-wide methylation analysis of the 46 unsolved familial and/or early-onset CRC patients, low-level methylation of the BRCA1 promoter (average β-value: 0.18; range β-value: 0.14–0.22) was detected in a male individual diagnosed with CRC at 37 years of age and with no reported family history of cancer (P-8) (Fig. 5A). Here, BRCA1 is linked to cancer.