Li et al. [71] used 27 K arrays in a small sample of ER/PR+ and ER/PR BC samples, and identified and validated four genes: FAM124B and ST6GALNAC1 were significantly hypermethylated, and NAV1 and PER1 were significantly hypomethylated in ER+/PR+ BC. The gene discussed is ESR1; the disease is breast cancer.