For the following genes, a correlation was found between the methylation levels in tumors and those in tumor-adjacent tissues: CDKN2A (promoter) (r = 0.927, p < 0.001); BRCA1 (r = 0.878, p < 0.001); APC (r = 0.706, p = 0.001), ESR1 (r = 0.545, p = 0.019) and ESR2 (r = 0.543, p = 0.024). The gene discussed is ESR1; the disease is neoplasm.