ESR1 and neoplasm: On the other hand, the stage (p = 0.0003), tumour size (p = 0.0029), histological grade SBR (p = 0.0011), lymph node status (p = 0.0288), oestrogen receptor status (p = 0.0054), metastasis (p < 0.0001) and death (p = 0.0105) were significantly associated with ESR1 gene methylation.